S. Pahwa - Academia.edu (original) (raw)

Papers by S. Pahwa

Research paper thumbnail of IL-7 administration drives T cell–cycle entry and expansion in HIV-1 infection

Blood, 2009

Interleukin 7 (IL-7) is a common gamma chain receptor cytokine implicated in thymopoiesis and in ... more Interleukin 7 (IL-7) is a common gamma chain receptor cytokine implicated in thymopoiesis and in peripheral expansion and survival of T lymphocytes. The safety and activity of recombinant human IL-7 (rhIL-7) administration were therefore examined in HIV-infected persons. In this prospective randomized placebo-controlled study, a single subcutaneous dose of rhIL-7 was well tolerated with biologic activity demonstrable at 3 μg/kg and a maximum tolerated dose of 30 μg/kg. Injection site reactions and transient elevations of liver function tests were the most notable side effects. Transient increases in plasma HIV-RNA levels were observed in 6 of 11 IL-7–treated patients. Recombinant hIL-7 induced CD4 and CD8 T cells to enter cell cycle; cell-cycle entry was also confirmed in antigen-specific CD8 T cells. Administration of rhIL-7 led to transient down-regulation of the IL-7 receptor alpha chain (CD127) in both CD4+ and CD8+ T cells. Single-dose rhIL-7 increased the numbers of circulatin...

Research paper thumbnail of Interleukin-2 Therapy in HIV Infection

AIDS Patient Care and STDs, 1998

Methods for promoting immunologic control of human immunodeficiency virus (HIV) in an HIV-infecte... more Methods for promoting immunologic control of human immunodeficiency virus (HIV) in an HIV-infected subject are provided. The methods comprise administering to the subject highly active antiretroviral therapy (HAART) for at least one cycle of an intermittent dosing regimen in combi nation with administration of a pharmaceutical composition comprising a therapeutically effective amount of interleu kin-2 (IL-2) or variant thereof. The combination of daily or intermittent administration of IL-2 (or variant thereof) and intermittent HAART promotes immunologic control of viral replication in the absence of HAART, thereby prolonging the length of time a patient may discontinue HAART before viral rebound necessitates further administration of HAART. Administration of IL-2 therapy in combination with an intermittent HAART dosing regimen provides an effective method for treating a subject infected with HIV.

Research paper thumbnail of Upregulation of human immunodeficiency virus-1 in chronically infected monocytic cell line by both contact with endothelial cells and cytokines

Blood, 1994

Cells of monocytic lineage (Mo) persistently infected with human immunodeficiency virus (HIV) hav... more Cells of monocytic lineage (Mo) persistently infected with human immunodeficiency virus (HIV) have been suspected to be a major reservoir for in vivo transmission of virus to susceptible target cells. Cellular events and mechanisms that upregulate viral gene expression in such cells are important issues. Because the traffic of such cells is central to biodistribution of HIV, we have explored the impact of interaction of endothelium with HIV-1-infected U1 promonocytic cells. Coculturing of U1 with human umbilical endothelial cells (HUVEC) for 24 to 72 hours in the absence of stimulation induced HIV-1 p24 biosynthesis significantly. Antibody-blocking experiments indicated that CD11/CD18 integrins play a role in upregulation of HIV expression elicited by interaction with HUVEC. Engagement of CD11b/CD18 by adherence of U1 to surfaces coated with either the cognate ligand fibrinogen or monoclonal antibody specific for CD11b/CD18 also enhanced p24 biosynthesis. Furthermore, endothelial ce...

Research paper thumbnail of Envelope glycoproteins of Human Immunodeficiency Virus type 1 variants issued from mother–infant pairs display a wide spectrum of biological properties

Virology, 2012

Mother-to-child transmission Env-pseudotyped viruses Biological properties Neutralization CFR01_A... more Mother-to-child transmission Env-pseudotyped viruses Biological properties Neutralization CFR01_AE clade Several studies have shown that the early virus population present in HIV-1 infected infants usually is homogeneous when compared to the highly diversified viral population present at delivery in their mothers. We explored the antigenic and functional properties of pseudotyped viruses expressing gp120 encoded by env clones issued from four mother-infant pairs infected by CRF01_AE viruses. We compared their sensitivity to neutralization and to entry inhibitors, their infectivity levels and the Env processing and incorporation levels. We found that both transmitted viruses present in infants and the variants present in their chronically infected mothers display a wide spectrum of biological properties that could not distinguish between them. In contrast, we found that all the transmitted viruses in the infants were more sensitive to neutralization by PG9 and PG16 than the maternal variants, an observation that may have implications for the development of prophylactic strategies to prevent mother-to-child transmission.

Research paper thumbnail of Immune Activation in HIV-Infected Aging Women on Antiretrovirals—Implications for Age-Associated Comorbidities: A Cross-Sectional Pilot Study

PLoS ONE, 2013

Background: Persistent immune activation and microbial translocation associated with HIV infectio... more Background: Persistent immune activation and microbial translocation associated with HIV infection likely place HIVinfected aging women at high risk of developing chronic age-related diseases. We investigated immune activation and microbial translocation in HIV-infected aging women in the post-menopausal ages. Methods: Twenty-seven post-menopausal women with HIV infection receiving antiretroviral treatment with documented viral suppression and 15 HIV-negative age-matched controls were enrolled. Levels of immune activation markers (T cell immune phenotype, sCD25, sCD14, sCD163), microbial translocation (LPS) and biomarkers of cardiovascular disease and impaired cognitive function (sVCAM-1, sICAM-1 and CXCL10) were evaluated. Results: T cell activation and exhaustion, monocyte/macrophage activation, and microbial translocation were significantly higher in HIV-infected women when compared to uninfected controls. Microbial translocation correlated with T cell and monocyte/macrophage activation. Biomarkers of cardiovascular disease and impaired cognition were elevated in women with HIV infection and correlated with immune activation. Conclusions: HIV-infected antiretroviral-treated aging women who achieved viral suppression are in a generalized status of immune activation and therefore are at an increased risk of age-associated end-organ diseases compared to uninfected agematched controls.

Research paper thumbnail of Rationale for combined use of fetal liver and thymus for immunological reconstitution in patients with variants of severe combined immunodeficiency

Proceedings of the National Academy of Sciences, 1977

Bone marrow cells from a patient with severe combined immunodeficiency were studied in vitro for ... more Bone marrow cells from a patient with severe combined immunodeficiency were studied in vitro for thymus-dependent lymphocyte (T cell) differentiation by using, at varying times, thymic epithelial monolayers and culture supernatants, thymopoietin, ubiquitin, and thymic extract as inducing agents. On initial evaluation, with thymopoietin or human thymic extract, only a partial differentiation of marrow cells was achieved into cells bearing the human T cell antigenicity without the capacity to form rosettes with sheep erythrocytes, suggesting that the stem cells were defective. Two fetal liver transplantations aimed at reconstitution were unsuccessful, despite evidence of chimerism. Induction studies at that time demonstrated rosetting capacity (with sheep erythrocytes) of the patient's bone marrow cells after coculture with thymic epithelial monolayers but not with their supernatants. An 18-week fetal thymus (irradiated) was then transplanted, but the transplantation was unsuccess...

Research paper thumbnail of Thymic activity in severe combined immunodeficiency diseases

Proceedings of the National Academy of Sciences, 1977

Thymic function was evaluated by quantitation of circulating thymic factor in patients with sever... more Thymic function was evaluated by quantitation of circulating thymic factor in patients with several forms of severe infantile immunodeficiency diseases. Direct quantitation of thymic factor in serum of patients with severe combined immunodeficiency revealed heterogeneity of this syndrome by this parameter, as was also shown by study of susceptibility of the marrow cells to differentiation in vitro. Thymic factor was not detectable in one patient with severe combined immunodeficiency, but was present in normal or near-normal concentrations in three others. Circulating levels of this hormonal activity were also not detectable in a patient with DiGeorge athymic syndrome. Following marrow or fetal liver transplantation, which corrected the severe combined immunodeficiency thymic factor levels either increased slightly or did not change appreciably. Fetal thymic transplantation, which together with fetal liver transplantation corrected the immunodeficiency in one patient with severe comb...

Research paper thumbnail of Prematurity, hypogammaglobulinemia, and neuropathology with human immunodeficiency virus (HIV) infection

Proceedings of the National Academy of Sciences, 1987

Infection with the human immunodeficiency virus (HIV) is characteristically associated with hyper... more Infection with the human immunodeficiency virus (HIV) is characteristically associated with hypergammaglobulinemia in both adult and pediatric cases. We report herein four infants who had an HIV infection in association with severe hypogammaglobulinemia and did not exhibit antibodies against HIV. HIV was isolated antemortem or postmortem in all four infants from either peripheral blood, cerebrospinal fluid, or body tissues. HIV infection could be presumed to be acquired transplacentally in two infants and by way of infected blood transfusions during the neonatal period in the other two. Each infant became symptomatic within the first year of life and developed rapidly progressive manifestations of the disease. Features that were common to all four infants include premature birth, failure to thrive, hepatomegaly, and progressive neurological abnormalities that were associated with intracranial calcifications. We concluded that, when infection occurs early in development either by tra...

Research paper thumbnail of Long-Term Engraftment of Human Natural T Regulatory Cells in NOD/SCID IL2rγcnull Mice by Expression of Human IL-2

PLoS ONE, 2012

Regulatory T cells are essential to maintain immune homeostasis and prevent autoimmunity. Therapy... more Regulatory T cells are essential to maintain immune homeostasis and prevent autoimmunity. Therapy with in vitro expanded human nT Regs is being tested to prevent graft versus host disease, which is a major cause for morbidity and mortality associated with hematopoietic stem cell transplantation. Their usefulness in therapy will depend on their capacity to survive, migrate appropriately and retain suppressive activity when introduced into a transplant recipient. The lack of a suitable animal model for studying the in vivo reconstitutive capability of human nT Regs is a major impediment for investigating the behavior of adoptively transferred nT Regs in vivo. We show that injection of a plasmid encoding human IL-2 is necessary and sufficient for long term engraftment of in vitro expanded nT Regs in NOD-SCID IL2rcc null mice. We also demonstrate that these in vivo reconstituted T Regs traffic to different organs of the body and retain suppressive function. Finally, in an IL-2 accelerated GVHD model, we show that these in vivo reconstituted T Regs are capable of preventing severe xenogenic response of human PBMCs. Thus, this novel 'hu-T Reg mouse' model offers a pre-clinical platform to study the in vivo function and stability of human nT Regs and their ability to modulate autoimmune diseases and GVHD.

Research paper thumbnail of CD4+/CD8+ T Cell Ratio for Diagnosis of HIV-1 Infection in Infants: Women and Infants Transmission Study

Pediatrics, 2008

OBJECTIVE. In this study, we tested the hypothesis that the CD4+/CD8+ T cell ratio could predict ... more OBJECTIVE. In this study, we tested the hypothesis that the CD4+/CD8+ T cell ratio could predict HIV infection status in HIV-exposed infants. METHODS. CD4+/CD8+ T cell ratios were determined from data for live-born singleton infants who had been prospectively enrolled in the Women and Infants Transmission Study. Data for 2208 infants with known HIV infection status (179 HIV-infected and 2029 uninfected infants) were analyzed. RESULTS. Receiver operating characteristic curves indicated that the CD4+/CD8+ T cell ratio performed better than the proportion of CD4+ T cells for diagnosis of HIV infection as early as 2 months of age, and this relationship was unaffected by adjustment for maternal race/ethnicity, infant birth weight, gestational age, and gender. At 4 months of age, 90% specificity for HIV diagnosis was associated with 60% sensitivity. For ease of use, graphical estimates based on cubic splines for the time-dependent parameters in a Box-Cox transformation (L), the median (M)...

Research paper thumbnail of Immunologic Functions in Chronic Active Hepatitis (Cah) of Childhood

Research paper thumbnail of Low CD4+ T-Cell Levels and B-Cell Apoptosis in Vertically HIV-exposed Noninfected Children and Adolescents

Journal of Tropical Pediatrics, 2010

Lymphocyte subsets, activation markers and apoptosis were assessed in 20 HIV-exposed noninfected ... more Lymphocyte subsets, activation markers and apoptosis were assessed in 20 HIV-exposed noninfected (ENI) children born to HIV-infected women who were or not exposed to antiretroviral (ARV) drugs during pregnancy and early infancy. ENI children and adolescents were aged 6-18 years and they were compared to 25 age-matched healthy non-HIV-exposed children and adolescents (Control). ENI individuals presented lower CD4 þ T cells/mm 3 than Control group (control: 1120.3 vs. ENI: 876.3; t-test, p ¼ 0.030). ENI individuals had higher B-cell apoptosis than Control group (Control: 36.6%, ARV exposed: 82.3%, ARV nonexposed: 68.5%; Kruskal-Wallis, p < 0.05), but no statistical difference was noticed between those exposed and not exposed to ARV. Immune activation in CD4 þ T, CD8 þ T and in B cells was comparable in ENI and in Control children and adolescents. Subtle long-term immune alterations might persist among ENI individuals, but the clinical consequences if any are unknown, and these children require continued monitoring.

Research paper thumbnail of Membrane and Soluble Forms of Fas (CD95) and Fas Ligand in Peripheral Blood Mononuclear Cells and in Plasma from Human Immunodeficiency Virus‐Infected Persons

The Journal of Infectious Diseases, 1998

The expression of membrane-bound Fas ligand (FasL) and Fas in lymphocytes and monocytes and level... more The expression of membrane-bound Fas ligand (FasL) and Fas in lymphocytes and monocytes and levels of soluble forms of FasL (sFasL) and Fas (sFas) in plasma from human immunodeficiency virus (HIV)-positive and-negative subjects was evaluated. Surface FasL was detectable on monocytes, but poorly so on lymphocytes, even in the presence of KB8301, a metalloproteinase inhibitor. Unexpectedly, monocytes of HIV-positive subjects expressed less FasL than those of HIV-negative volunteers. sFasL levels in plasma of HIV-positive persons were elevated and correlated with levels in plasma and with HIV RNA burden. sFas levels in plasma of HIV-positive subjects were also elevated and correlated with Fas expression in apoptotic lymphocytes. Finally, culture-induced lymphocyte apoptosis of HIV-positive subjects was enhanced by anti-Fas agonistic antibody but was not inhibited by anti-FasL blocking antibodies. These results suggest that significant dysregulation of both Fas and FasL occurs in HIV infection and contributes to increased sensitivity of lymphocytes to apoptosis.

Research paper thumbnail of Alterations in Apoptosis of Cord and Adult Peripheral Blood Mononuclear Cells Induced by In Vitro Infection with Respiratory Syncytial Virus

The Journal of Infectious Diseases, 2000

Research paper thumbnail of Laboratory Diagnosis of Infection Status in Infants Perinatally Exposed to Human Immunodeficiency Virus Type 1

Journal of Infectious Diseases, 1996

Accurate and timely diagnosisof infection status in infants born to women infected with human imm... more Accurate and timely diagnosisof infection status in infants born to women infected with human immunodeficiency virus (HIV) is of paramount importance. The comparative accuracy of five diagnostic decision rules was evaluated in 208 HIV-exposed infants (32 infected, 176 uninfected) based on laboratory testing during the first 6 months of life. Diagnostic rules A and B, which required single blood samples analyzed by culture and polymerase chain reaction (PCR) (rule A) or culture, PCR, and p24 antigen detection (rule B) were more prone to incorrect diagnoses than were rules requiring 2 blood samples analyzed by a singleassay (rule C) or combinations of culture and PCR (rules D and E). Rule D, which used PCR as the initial test, established the most useful algorithm: a positive PCR result followed by a positive culture in the second sample confirmed infected status, while two consecutive negativePCR results reconfirmed as negative at 6 months of age established uninfected status. The major cause of human immunodeficiency virus (HIV) infection in children is maternal-infant transmission, which, in the absence of antiretroviral treatment, occurs at a rate of 20%-25% in infants born to HIV-infected women in the United States. Therapies aimed at preventing maternal-infant HIV transmission are expected to decrease infection rates considerably in HIV-exposed infants [1]. Early determination of HIV infection status among infants perinatally exposed to HIV is of crucial importance for identifying infected as well as uninfected infants. Conventional clinical and serologic parameters result in diagnosis of AIDS or HIV infection within the first year of life in only 14% of vertically infected children [2]. By contrast, studies using virologic laboratory methods-culture, HIV p24 antigen detection, and polymerase chain reaction (PCR)-indicate that a laboratory diagnosis of an HIV-infected child can be made with 50% sensitivity and up to 100% specificity in infants examined at birth [3] and with >90% sensitivity and specificity for HIV-exposed infants by age 6 months [4-8].

Research paper thumbnail of X-linked severe combined immunodeficiency. Diagnosis in males with sporadic severe combined immunodeficiency and clarification of clinical findings

Journal of Clinical Investigation, 1990

Over 80% of infants with severe combined immunodeficiency (SCID) of unknown genetic etiology are ... more Over 80% of infants with severe combined immunodeficiency (SCID) of unknown genetic etiology are males, yet less than a third of these affected males have a family history of X-linked disease. To help identify new mutations of the X-linked SCID gene and to provide genetic counseling, X chromosome inactivation patterns in T cells from 16 women who had sons with sporadic SCID were examined. Between 9 and 35 human/ hamster hybrids that selectively retained the active human X chromosome were produced from the T cells of each woman and analyzed with an X-linked restriction fragment length polymorphism for which the woman in question was heterozygous. Exclusive use of a single X as the active X was seen in the T cell hybrids from 7 of the 16 women, identifying these women as carriers of X-linked SCID. Studies on additional family members confirmed the mutant nature of the inactive X and revealed the source of the new mutation in three families. To determine whether there were any laboratory characteristics that might differentiate the boys whose mothers were identified as carriers of X-linked SCID from those whose mothers were not, the clinical records of both groups were compared to each other and to a group of 14 boys with a family history of X-linked SCID. The most consistent finding in the 21 patients with X-linked SCID was an elevated proportion of B cells. These data demonstrate the high incidence of spontaneous mutation for the X-linked SCID gene and help clarify the characteristic presenting features of this disorder.

Research paper thumbnail of Predictive Value of Quantitative Plasma HIV RNA and CD4+ Lymphocyte Count in HIV-Infected Infants and Children

JAMA, 1998

Context.-Pediatric human immunodeficiency virus (HIV) infection has unique viral pathogenetic fea... more Context.-Pediatric human immunodeficiency virus (HIV) infection has unique viral pathogenetic features that preclude routine extrapolation from adult studies and require specific analysis. Objectives.-To evaluate the prognostic value of 2 key laboratory markersplasma RNA and CD4 + lymphocyte count-for HIV disease progression in infants and children and to establish targeted values for optimal outcome. Design.-Data from a cohort of 566 infants and children who participated in a randomized, placebo-controlled trial of nucleoside reverse transcriptase inhibitors (ACTG 152) were analyzed. The trial was conducted between 1991 and 1995 and enrolled a heterogenous cohort of antiretroviral therapy-naive children (age, 3 months to 18 years); patients had a median follow-up of 32 months. Main Outcome Measures.-The trial clinical end points consisted of time to first HIV disease progression (growth failure, decline in neurologic or neurodevelopmental function, opportunistic infections) or death. Results.-Baseline plasma RNA levels were high (age group medians, 5ϫ10 4 to Ͼ10 6 copies/mL), and both baseline RNA and CD4 + lymphocyte count were independently predictive of subsequent clinical course. Risk reduction for disease progression between 49% and 64% was observed for each log 10 reduction in baseline RNA and was linear without suggestion of a threshold or age effect. Disease progression predictive power was enhanced by the combined use of plasma RNA and CD4 + cell count. Marker values of less than 10 000 copies/mL for plasma RNA and greater than 500ϫ10 6 /L (Ͻ6.5 years of age) or greater than 200ϫ10 6 /L (Ͼ6.5 years) for CD4 + cell count were associated with a 2-year disease progression rate of less than 5%. Conclusions.-Two key laboratory markers-plasma RNA and CD4 + lymphocyte count-are independent predictors of clinical course among HIV-infected infants and children. The linear, age-independent relationship between log 10 plasma RNA and relative risk of disease progression strongly supports therapeutic efforts to achieve plasma virus levels as low as possible.

Research paper thumbnail of Antimicrobial-Specific Cell-Mediated Immune Reconstitution in Children with Advanced Human Immunodeficiency Virus Infection Receiving Highly Active Antiretroviral Therapy

Clinical Infectious Diseases, 2004

To identify virological and immunological correlates of microbial-specific immune reconstitution ... more To identify virological and immunological correlates of microbial-specific immune reconstitution in children with advanced human immunodeficiency virus (HIV) infection, Candida-and tetanus-specific lymphocyte proliferation was measured in 165 children initiating a new highly active antiretroviral therapy (HAART) regimen. During the study, the proportions of children with immunity to Candida and tetanus increased from 53% to 66% and 19% to 22%, respectively. Tetanus immunity was associated with an HIV load р400 RNA copies/mL and with Candida immunity. At the end of the study, 23% of the patients with baseline negative lymphocyte proliferation had tetanus immunity, and 65% had Candida immunity. Reconstitution of tetanus immunity correlated with lower end-of-study HIV loads and activated CD8 + cell percentages and higher baseline and in-study CD4 + cell percentages, but not with a gain of CD4 + cells. Reconstitution of Candida immunity showed similar trends. In conclusion, children with advanced HIV infection receiving HAART reconstituted Candida immunity more readily than they did tetanus immunity, suggesting a role for antigen reexposure. Additional factors for immune reconstitution were low HIV load, high CD4 + cell percentages, and low levels of activated CD8 + cells. HIV preferentially destroys CD4 + T lymphocytes and interferes with other components of the immune system, thereby weakening defenses against infections [1-4]. However, it is unclear to what extent functional deficits account for the immunodeficient state of pa

Research paper thumbnail of Diagnosis of Human Immunodeficiency Virus Type 1 Infection with Different Subtypes Using Rapid Tests

Clinical Diagnostic Laboratory Immunology, 2000

We evaluated six rapid tests for their sensitivity and specificity in diagnosing human immunodefi... more We evaluated six rapid tests for their sensitivity and specificity in diagnosing human immunodeficiency virus type 1 (HIV-1) infection using 241 specimens (172 HIV-1 positive, 69 HIV-1 negative) representing different HIV-1 subtypes (A [ n = 40], B [ n = 47], C [ n = 28], E [ n = 42], and F [ n = 7]). HIVCHEK, Multispot, RTD and SeroStrip were 100% sensitive and specific. Capillus failed to identify two of eight subtype C specimens (overall sensitivity of 98.85%), while the SUDS test (the only test approved by the Food and Drug Administration) gave false-positive results for 5 of 69 seronegative specimens (specificity of 93.24%). Our results suggest that although rapid tests perform well in general, it may be prudent to evaluate a rapid test for sensitivity and specificity in a local population prior to its widespread use.

Research paper thumbnail of Comparison of Immunologic Assays for Detecting Immune Responses in HIV Immunotherapeutic Studies: AIDS Clinical Trials Group Trial A5181

Clinical and Vaccine Immunology, 2010

This study was designed to evaluate which of several T-cell-specific, immune response assays are ... more This study was designed to evaluate which of several T-cell-specific, immune response assays are the most relevant in measuring the key characteristics of an effective immune response to HIV-1. Using 5 HIV-1 antigens as stimulants, we assessed lymphocyte proliferation, supernatant gamma interferon (IFN-γ) cytokine production (CP), single-cell IFN-γ production by enzyme-linked immunospot (ELISPOT) assay, with and without Epstein-Barr virus-transformed B-lymphoblastoid cell lines (B-LCLs), and intracellular cytokine production (ICC) for IFN-γ and interleukin 2 (IL-2) by flow cytometry. We used these to compare specimens from HIV-1-infected subjects who were virally suppressed with a stable antiretroviral therapy (ART) regimen (group A) with specimens from subjects not on ART but with HIV-1 viremia of <3,000 copies/ml (group B). The lymphocyte proliferation assay (LPA) did not significantly differentiate between the two groups. Using fresh peripheral blood mononuclear cells (PBMCs),...

Research paper thumbnail of IL-7 administration drives T cell–cycle entry and expansion in HIV-1 infection

Blood, 2009

Interleukin 7 (IL-7) is a common gamma chain receptor cytokine implicated in thymopoiesis and in ... more Interleukin 7 (IL-7) is a common gamma chain receptor cytokine implicated in thymopoiesis and in peripheral expansion and survival of T lymphocytes. The safety and activity of recombinant human IL-7 (rhIL-7) administration were therefore examined in HIV-infected persons. In this prospective randomized placebo-controlled study, a single subcutaneous dose of rhIL-7 was well tolerated with biologic activity demonstrable at 3 μg/kg and a maximum tolerated dose of 30 μg/kg. Injection site reactions and transient elevations of liver function tests were the most notable side effects. Transient increases in plasma HIV-RNA levels were observed in 6 of 11 IL-7–treated patients. Recombinant hIL-7 induced CD4 and CD8 T cells to enter cell cycle; cell-cycle entry was also confirmed in antigen-specific CD8 T cells. Administration of rhIL-7 led to transient down-regulation of the IL-7 receptor alpha chain (CD127) in both CD4+ and CD8+ T cells. Single-dose rhIL-7 increased the numbers of circulatin...

Research paper thumbnail of Interleukin-2 Therapy in HIV Infection

AIDS Patient Care and STDs, 1998

Methods for promoting immunologic control of human immunodeficiency virus (HIV) in an HIV-infecte... more Methods for promoting immunologic control of human immunodeficiency virus (HIV) in an HIV-infected subject are provided. The methods comprise administering to the subject highly active antiretroviral therapy (HAART) for at least one cycle of an intermittent dosing regimen in combi nation with administration of a pharmaceutical composition comprising a therapeutically effective amount of interleu kin-2 (IL-2) or variant thereof. The combination of daily or intermittent administration of IL-2 (or variant thereof) and intermittent HAART promotes immunologic control of viral replication in the absence of HAART, thereby prolonging the length of time a patient may discontinue HAART before viral rebound necessitates further administration of HAART. Administration of IL-2 therapy in combination with an intermittent HAART dosing regimen provides an effective method for treating a subject infected with HIV.

Research paper thumbnail of Upregulation of human immunodeficiency virus-1 in chronically infected monocytic cell line by both contact with endothelial cells and cytokines

Blood, 1994

Cells of monocytic lineage (Mo) persistently infected with human immunodeficiency virus (HIV) hav... more Cells of monocytic lineage (Mo) persistently infected with human immunodeficiency virus (HIV) have been suspected to be a major reservoir for in vivo transmission of virus to susceptible target cells. Cellular events and mechanisms that upregulate viral gene expression in such cells are important issues. Because the traffic of such cells is central to biodistribution of HIV, we have explored the impact of interaction of endothelium with HIV-1-infected U1 promonocytic cells. Coculturing of U1 with human umbilical endothelial cells (HUVEC) for 24 to 72 hours in the absence of stimulation induced HIV-1 p24 biosynthesis significantly. Antibody-blocking experiments indicated that CD11/CD18 integrins play a role in upregulation of HIV expression elicited by interaction with HUVEC. Engagement of CD11b/CD18 by adherence of U1 to surfaces coated with either the cognate ligand fibrinogen or monoclonal antibody specific for CD11b/CD18 also enhanced p24 biosynthesis. Furthermore, endothelial ce...

Research paper thumbnail of Envelope glycoproteins of Human Immunodeficiency Virus type 1 variants issued from mother–infant pairs display a wide spectrum of biological properties

Virology, 2012

Mother-to-child transmission Env-pseudotyped viruses Biological properties Neutralization CFR01_A... more Mother-to-child transmission Env-pseudotyped viruses Biological properties Neutralization CFR01_AE clade Several studies have shown that the early virus population present in HIV-1 infected infants usually is homogeneous when compared to the highly diversified viral population present at delivery in their mothers. We explored the antigenic and functional properties of pseudotyped viruses expressing gp120 encoded by env clones issued from four mother-infant pairs infected by CRF01_AE viruses. We compared their sensitivity to neutralization and to entry inhibitors, their infectivity levels and the Env processing and incorporation levels. We found that both transmitted viruses present in infants and the variants present in their chronically infected mothers display a wide spectrum of biological properties that could not distinguish between them. In contrast, we found that all the transmitted viruses in the infants were more sensitive to neutralization by PG9 and PG16 than the maternal variants, an observation that may have implications for the development of prophylactic strategies to prevent mother-to-child transmission.

Research paper thumbnail of Immune Activation in HIV-Infected Aging Women on Antiretrovirals—Implications for Age-Associated Comorbidities: A Cross-Sectional Pilot Study

PLoS ONE, 2013

Background: Persistent immune activation and microbial translocation associated with HIV infectio... more Background: Persistent immune activation and microbial translocation associated with HIV infection likely place HIVinfected aging women at high risk of developing chronic age-related diseases. We investigated immune activation and microbial translocation in HIV-infected aging women in the post-menopausal ages. Methods: Twenty-seven post-menopausal women with HIV infection receiving antiretroviral treatment with documented viral suppression and 15 HIV-negative age-matched controls were enrolled. Levels of immune activation markers (T cell immune phenotype, sCD25, sCD14, sCD163), microbial translocation (LPS) and biomarkers of cardiovascular disease and impaired cognitive function (sVCAM-1, sICAM-1 and CXCL10) were evaluated. Results: T cell activation and exhaustion, monocyte/macrophage activation, and microbial translocation were significantly higher in HIV-infected women when compared to uninfected controls. Microbial translocation correlated with T cell and monocyte/macrophage activation. Biomarkers of cardiovascular disease and impaired cognition were elevated in women with HIV infection and correlated with immune activation. Conclusions: HIV-infected antiretroviral-treated aging women who achieved viral suppression are in a generalized status of immune activation and therefore are at an increased risk of age-associated end-organ diseases compared to uninfected agematched controls.

Research paper thumbnail of Rationale for combined use of fetal liver and thymus for immunological reconstitution in patients with variants of severe combined immunodeficiency

Proceedings of the National Academy of Sciences, 1977

Bone marrow cells from a patient with severe combined immunodeficiency were studied in vitro for ... more Bone marrow cells from a patient with severe combined immunodeficiency were studied in vitro for thymus-dependent lymphocyte (T cell) differentiation by using, at varying times, thymic epithelial monolayers and culture supernatants, thymopoietin, ubiquitin, and thymic extract as inducing agents. On initial evaluation, with thymopoietin or human thymic extract, only a partial differentiation of marrow cells was achieved into cells bearing the human T cell antigenicity without the capacity to form rosettes with sheep erythrocytes, suggesting that the stem cells were defective. Two fetal liver transplantations aimed at reconstitution were unsuccessful, despite evidence of chimerism. Induction studies at that time demonstrated rosetting capacity (with sheep erythrocytes) of the patient's bone marrow cells after coculture with thymic epithelial monolayers but not with their supernatants. An 18-week fetal thymus (irradiated) was then transplanted, but the transplantation was unsuccess...

Research paper thumbnail of Thymic activity in severe combined immunodeficiency diseases

Proceedings of the National Academy of Sciences, 1977

Thymic function was evaluated by quantitation of circulating thymic factor in patients with sever... more Thymic function was evaluated by quantitation of circulating thymic factor in patients with several forms of severe infantile immunodeficiency diseases. Direct quantitation of thymic factor in serum of patients with severe combined immunodeficiency revealed heterogeneity of this syndrome by this parameter, as was also shown by study of susceptibility of the marrow cells to differentiation in vitro. Thymic factor was not detectable in one patient with severe combined immunodeficiency, but was present in normal or near-normal concentrations in three others. Circulating levels of this hormonal activity were also not detectable in a patient with DiGeorge athymic syndrome. Following marrow or fetal liver transplantation, which corrected the severe combined immunodeficiency thymic factor levels either increased slightly or did not change appreciably. Fetal thymic transplantation, which together with fetal liver transplantation corrected the immunodeficiency in one patient with severe comb...

Research paper thumbnail of Prematurity, hypogammaglobulinemia, and neuropathology with human immunodeficiency virus (HIV) infection

Proceedings of the National Academy of Sciences, 1987

Infection with the human immunodeficiency virus (HIV) is characteristically associated with hyper... more Infection with the human immunodeficiency virus (HIV) is characteristically associated with hypergammaglobulinemia in both adult and pediatric cases. We report herein four infants who had an HIV infection in association with severe hypogammaglobulinemia and did not exhibit antibodies against HIV. HIV was isolated antemortem or postmortem in all four infants from either peripheral blood, cerebrospinal fluid, or body tissues. HIV infection could be presumed to be acquired transplacentally in two infants and by way of infected blood transfusions during the neonatal period in the other two. Each infant became symptomatic within the first year of life and developed rapidly progressive manifestations of the disease. Features that were common to all four infants include premature birth, failure to thrive, hepatomegaly, and progressive neurological abnormalities that were associated with intracranial calcifications. We concluded that, when infection occurs early in development either by tra...

Research paper thumbnail of Long-Term Engraftment of Human Natural T Regulatory Cells in NOD/SCID IL2rγcnull Mice by Expression of Human IL-2

PLoS ONE, 2012

Regulatory T cells are essential to maintain immune homeostasis and prevent autoimmunity. Therapy... more Regulatory T cells are essential to maintain immune homeostasis and prevent autoimmunity. Therapy with in vitro expanded human nT Regs is being tested to prevent graft versus host disease, which is a major cause for morbidity and mortality associated with hematopoietic stem cell transplantation. Their usefulness in therapy will depend on their capacity to survive, migrate appropriately and retain suppressive activity when introduced into a transplant recipient. The lack of a suitable animal model for studying the in vivo reconstitutive capability of human nT Regs is a major impediment for investigating the behavior of adoptively transferred nT Regs in vivo. We show that injection of a plasmid encoding human IL-2 is necessary and sufficient for long term engraftment of in vitro expanded nT Regs in NOD-SCID IL2rcc null mice. We also demonstrate that these in vivo reconstituted T Regs traffic to different organs of the body and retain suppressive function. Finally, in an IL-2 accelerated GVHD model, we show that these in vivo reconstituted T Regs are capable of preventing severe xenogenic response of human PBMCs. Thus, this novel 'hu-T Reg mouse' model offers a pre-clinical platform to study the in vivo function and stability of human nT Regs and their ability to modulate autoimmune diseases and GVHD.

Research paper thumbnail of CD4+/CD8+ T Cell Ratio for Diagnosis of HIV-1 Infection in Infants: Women and Infants Transmission Study

Pediatrics, 2008

OBJECTIVE. In this study, we tested the hypothesis that the CD4+/CD8+ T cell ratio could predict ... more OBJECTIVE. In this study, we tested the hypothesis that the CD4+/CD8+ T cell ratio could predict HIV infection status in HIV-exposed infants. METHODS. CD4+/CD8+ T cell ratios were determined from data for live-born singleton infants who had been prospectively enrolled in the Women and Infants Transmission Study. Data for 2208 infants with known HIV infection status (179 HIV-infected and 2029 uninfected infants) were analyzed. RESULTS. Receiver operating characteristic curves indicated that the CD4+/CD8+ T cell ratio performed better than the proportion of CD4+ T cells for diagnosis of HIV infection as early as 2 months of age, and this relationship was unaffected by adjustment for maternal race/ethnicity, infant birth weight, gestational age, and gender. At 4 months of age, 90% specificity for HIV diagnosis was associated with 60% sensitivity. For ease of use, graphical estimates based on cubic splines for the time-dependent parameters in a Box-Cox transformation (L), the median (M)...

Research paper thumbnail of Immunologic Functions in Chronic Active Hepatitis (Cah) of Childhood

Research paper thumbnail of Low CD4+ T-Cell Levels and B-Cell Apoptosis in Vertically HIV-exposed Noninfected Children and Adolescents

Journal of Tropical Pediatrics, 2010

Lymphocyte subsets, activation markers and apoptosis were assessed in 20 HIV-exposed noninfected ... more Lymphocyte subsets, activation markers and apoptosis were assessed in 20 HIV-exposed noninfected (ENI) children born to HIV-infected women who were or not exposed to antiretroviral (ARV) drugs during pregnancy and early infancy. ENI children and adolescents were aged 6-18 years and they were compared to 25 age-matched healthy non-HIV-exposed children and adolescents (Control). ENI individuals presented lower CD4 þ T cells/mm 3 than Control group (control: 1120.3 vs. ENI: 876.3; t-test, p ¼ 0.030). ENI individuals had higher B-cell apoptosis than Control group (Control: 36.6%, ARV exposed: 82.3%, ARV nonexposed: 68.5%; Kruskal-Wallis, p < 0.05), but no statistical difference was noticed between those exposed and not exposed to ARV. Immune activation in CD4 þ T, CD8 þ T and in B cells was comparable in ENI and in Control children and adolescents. Subtle long-term immune alterations might persist among ENI individuals, but the clinical consequences if any are unknown, and these children require continued monitoring.

Research paper thumbnail of Membrane and Soluble Forms of Fas (CD95) and Fas Ligand in Peripheral Blood Mononuclear Cells and in Plasma from Human Immunodeficiency Virus‐Infected Persons

The Journal of Infectious Diseases, 1998

The expression of membrane-bound Fas ligand (FasL) and Fas in lymphocytes and monocytes and level... more The expression of membrane-bound Fas ligand (FasL) and Fas in lymphocytes and monocytes and levels of soluble forms of FasL (sFasL) and Fas (sFas) in plasma from human immunodeficiency virus (HIV)-positive and-negative subjects was evaluated. Surface FasL was detectable on monocytes, but poorly so on lymphocytes, even in the presence of KB8301, a metalloproteinase inhibitor. Unexpectedly, monocytes of HIV-positive subjects expressed less FasL than those of HIV-negative volunteers. sFasL levels in plasma of HIV-positive persons were elevated and correlated with levels in plasma and with HIV RNA burden. sFas levels in plasma of HIV-positive subjects were also elevated and correlated with Fas expression in apoptotic lymphocytes. Finally, culture-induced lymphocyte apoptosis of HIV-positive subjects was enhanced by anti-Fas agonistic antibody but was not inhibited by anti-FasL blocking antibodies. These results suggest that significant dysregulation of both Fas and FasL occurs in HIV infection and contributes to increased sensitivity of lymphocytes to apoptosis.

Research paper thumbnail of Alterations in Apoptosis of Cord and Adult Peripheral Blood Mononuclear Cells Induced by In Vitro Infection with Respiratory Syncytial Virus

The Journal of Infectious Diseases, 2000

Research paper thumbnail of Laboratory Diagnosis of Infection Status in Infants Perinatally Exposed to Human Immunodeficiency Virus Type 1

Journal of Infectious Diseases, 1996

Accurate and timely diagnosisof infection status in infants born to women infected with human imm... more Accurate and timely diagnosisof infection status in infants born to women infected with human immunodeficiency virus (HIV) is of paramount importance. The comparative accuracy of five diagnostic decision rules was evaluated in 208 HIV-exposed infants (32 infected, 176 uninfected) based on laboratory testing during the first 6 months of life. Diagnostic rules A and B, which required single blood samples analyzed by culture and polymerase chain reaction (PCR) (rule A) or culture, PCR, and p24 antigen detection (rule B) were more prone to incorrect diagnoses than were rules requiring 2 blood samples analyzed by a singleassay (rule C) or combinations of culture and PCR (rules D and E). Rule D, which used PCR as the initial test, established the most useful algorithm: a positive PCR result followed by a positive culture in the second sample confirmed infected status, while two consecutive negativePCR results reconfirmed as negative at 6 months of age established uninfected status. The major cause of human immunodeficiency virus (HIV) infection in children is maternal-infant transmission, which, in the absence of antiretroviral treatment, occurs at a rate of 20%-25% in infants born to HIV-infected women in the United States. Therapies aimed at preventing maternal-infant HIV transmission are expected to decrease infection rates considerably in HIV-exposed infants [1]. Early determination of HIV infection status among infants perinatally exposed to HIV is of crucial importance for identifying infected as well as uninfected infants. Conventional clinical and serologic parameters result in diagnosis of AIDS or HIV infection within the first year of life in only 14% of vertically infected children [2]. By contrast, studies using virologic laboratory methods-culture, HIV p24 antigen detection, and polymerase chain reaction (PCR)-indicate that a laboratory diagnosis of an HIV-infected child can be made with 50% sensitivity and up to 100% specificity in infants examined at birth [3] and with >90% sensitivity and specificity for HIV-exposed infants by age 6 months [4-8].

Research paper thumbnail of X-linked severe combined immunodeficiency. Diagnosis in males with sporadic severe combined immunodeficiency and clarification of clinical findings

Journal of Clinical Investigation, 1990

Over 80% of infants with severe combined immunodeficiency (SCID) of unknown genetic etiology are ... more Over 80% of infants with severe combined immunodeficiency (SCID) of unknown genetic etiology are males, yet less than a third of these affected males have a family history of X-linked disease. To help identify new mutations of the X-linked SCID gene and to provide genetic counseling, X chromosome inactivation patterns in T cells from 16 women who had sons with sporadic SCID were examined. Between 9 and 35 human/ hamster hybrids that selectively retained the active human X chromosome were produced from the T cells of each woman and analyzed with an X-linked restriction fragment length polymorphism for which the woman in question was heterozygous. Exclusive use of a single X as the active X was seen in the T cell hybrids from 7 of the 16 women, identifying these women as carriers of X-linked SCID. Studies on additional family members confirmed the mutant nature of the inactive X and revealed the source of the new mutation in three families. To determine whether there were any laboratory characteristics that might differentiate the boys whose mothers were identified as carriers of X-linked SCID from those whose mothers were not, the clinical records of both groups were compared to each other and to a group of 14 boys with a family history of X-linked SCID. The most consistent finding in the 21 patients with X-linked SCID was an elevated proportion of B cells. These data demonstrate the high incidence of spontaneous mutation for the X-linked SCID gene and help clarify the characteristic presenting features of this disorder.

Research paper thumbnail of Predictive Value of Quantitative Plasma HIV RNA and CD4+ Lymphocyte Count in HIV-Infected Infants and Children

JAMA, 1998

Context.-Pediatric human immunodeficiency virus (HIV) infection has unique viral pathogenetic fea... more Context.-Pediatric human immunodeficiency virus (HIV) infection has unique viral pathogenetic features that preclude routine extrapolation from adult studies and require specific analysis. Objectives.-To evaluate the prognostic value of 2 key laboratory markersplasma RNA and CD4 + lymphocyte count-for HIV disease progression in infants and children and to establish targeted values for optimal outcome. Design.-Data from a cohort of 566 infants and children who participated in a randomized, placebo-controlled trial of nucleoside reverse transcriptase inhibitors (ACTG 152) were analyzed. The trial was conducted between 1991 and 1995 and enrolled a heterogenous cohort of antiretroviral therapy-naive children (age, 3 months to 18 years); patients had a median follow-up of 32 months. Main Outcome Measures.-The trial clinical end points consisted of time to first HIV disease progression (growth failure, decline in neurologic or neurodevelopmental function, opportunistic infections) or death. Results.-Baseline plasma RNA levels were high (age group medians, 5ϫ10 4 to Ͼ10 6 copies/mL), and both baseline RNA and CD4 + lymphocyte count were independently predictive of subsequent clinical course. Risk reduction for disease progression between 49% and 64% was observed for each log 10 reduction in baseline RNA and was linear without suggestion of a threshold or age effect. Disease progression predictive power was enhanced by the combined use of plasma RNA and CD4 + cell count. Marker values of less than 10 000 copies/mL for plasma RNA and greater than 500ϫ10 6 /L (Ͻ6.5 years of age) or greater than 200ϫ10 6 /L (Ͼ6.5 years) for CD4 + cell count were associated with a 2-year disease progression rate of less than 5%. Conclusions.-Two key laboratory markers-plasma RNA and CD4 + lymphocyte count-are independent predictors of clinical course among HIV-infected infants and children. The linear, age-independent relationship between log 10 plasma RNA and relative risk of disease progression strongly supports therapeutic efforts to achieve plasma virus levels as low as possible.

Research paper thumbnail of Antimicrobial-Specific Cell-Mediated Immune Reconstitution in Children with Advanced Human Immunodeficiency Virus Infection Receiving Highly Active Antiretroviral Therapy

Clinical Infectious Diseases, 2004

To identify virological and immunological correlates of microbial-specific immune reconstitution ... more To identify virological and immunological correlates of microbial-specific immune reconstitution in children with advanced human immunodeficiency virus (HIV) infection, Candida-and tetanus-specific lymphocyte proliferation was measured in 165 children initiating a new highly active antiretroviral therapy (HAART) regimen. During the study, the proportions of children with immunity to Candida and tetanus increased from 53% to 66% and 19% to 22%, respectively. Tetanus immunity was associated with an HIV load р400 RNA copies/mL and with Candida immunity. At the end of the study, 23% of the patients with baseline negative lymphocyte proliferation had tetanus immunity, and 65% had Candida immunity. Reconstitution of tetanus immunity correlated with lower end-of-study HIV loads and activated CD8 + cell percentages and higher baseline and in-study CD4 + cell percentages, but not with a gain of CD4 + cells. Reconstitution of Candida immunity showed similar trends. In conclusion, children with advanced HIV infection receiving HAART reconstituted Candida immunity more readily than they did tetanus immunity, suggesting a role for antigen reexposure. Additional factors for immune reconstitution were low HIV load, high CD4 + cell percentages, and low levels of activated CD8 + cells. HIV preferentially destroys CD4 + T lymphocytes and interferes with other components of the immune system, thereby weakening defenses against infections [1-4]. However, it is unclear to what extent functional deficits account for the immunodeficient state of pa

Research paper thumbnail of Diagnosis of Human Immunodeficiency Virus Type 1 Infection with Different Subtypes Using Rapid Tests

Clinical Diagnostic Laboratory Immunology, 2000

We evaluated six rapid tests for their sensitivity and specificity in diagnosing human immunodefi... more We evaluated six rapid tests for their sensitivity and specificity in diagnosing human immunodeficiency virus type 1 (HIV-1) infection using 241 specimens (172 HIV-1 positive, 69 HIV-1 negative) representing different HIV-1 subtypes (A [ n = 40], B [ n = 47], C [ n = 28], E [ n = 42], and F [ n = 7]). HIVCHEK, Multispot, RTD and SeroStrip were 100% sensitive and specific. Capillus failed to identify two of eight subtype C specimens (overall sensitivity of 98.85%), while the SUDS test (the only test approved by the Food and Drug Administration) gave false-positive results for 5 of 69 seronegative specimens (specificity of 93.24%). Our results suggest that although rapid tests perform well in general, it may be prudent to evaluate a rapid test for sensitivity and specificity in a local population prior to its widespread use.

Research paper thumbnail of Comparison of Immunologic Assays for Detecting Immune Responses in HIV Immunotherapeutic Studies: AIDS Clinical Trials Group Trial A5181

Clinical and Vaccine Immunology, 2010

This study was designed to evaluate which of several T-cell-specific, immune response assays are ... more This study was designed to evaluate which of several T-cell-specific, immune response assays are the most relevant in measuring the key characteristics of an effective immune response to HIV-1. Using 5 HIV-1 antigens as stimulants, we assessed lymphocyte proliferation, supernatant gamma interferon (IFN-γ) cytokine production (CP), single-cell IFN-γ production by enzyme-linked immunospot (ELISPOT) assay, with and without Epstein-Barr virus-transformed B-lymphoblastoid cell lines (B-LCLs), and intracellular cytokine production (ICC) for IFN-γ and interleukin 2 (IL-2) by flow cytometry. We used these to compare specimens from HIV-1-infected subjects who were virally suppressed with a stable antiretroviral therapy (ART) regimen (group A) with specimens from subjects not on ART but with HIV-1 viremia of <3,000 copies/ml (group B). The lymphocyte proliferation assay (LPA) did not significantly differentiate between the two groups. Using fresh peripheral blood mononuclear cells (PBMCs),...