Antiplatelet glycoprotein autoantibodies in patients with autoimmune diseases with and without thrombocytopenia (original) (raw)
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Annals of Hematology, 1996
Autoimmune thrombocytopenic purpura (AITP) is most frequently induced by platelet-specific autoantibodies against epitopes on platelet GP Ib/IX or GP IIb/IIIa. These antibodies are reliably detected on the patients' autologous platelets. So far, studies on the characterization of platelet autoantibodies have been restricted to IgG antibodies. We used the monoclonal antibody immobilization of platelet antigens assay (MAIPA) in a modified version to detect GP-specific IgG, IgM, and IgA antibodies. Platelets of 46.2% of patients carried elevated amounts of IgG antibodies. IgM and IgA antibodies were observed less frequently and showed only weak OD signals in the MAIPA assay. Circulating IgG antibodies in serum were found in 11.5% of patients. Circulating IgM autoantibodies were observed in 8.9% and IgA antibodies in no patient with AITP. Results of direct MAIPA assay were compared with the reactivity of eluates in the platelet adhesion immunofluorescence assay and were found to be highly concordant. Patients with AITP in remission carried high percentages of anti-GP IIb/IIIa. Findings made in this study suggest that autoantibodies of the IgM and IgA classes play only a minor role in the pathogenesis of AITP.
American Journal of Hematology, 2003
Platelet antibodies are detectable in only about 50% of patients with chronic autoimmune thrombocytopenia (AITP). We determined platelet antibodies against GPIa/IIa, GPIb/IX, GPIIb/IIIa, and GPV and reticulated platelets in three female patients with AITP, before and after immunoadsorption treatment. None of the three patients' sera contained platelet antibodies prior to treatment. Thereafter, anti-GPIIb/IIIa, anti-GPIb/IX (n = 3), and anti-GPV (n = 1) were detectable in the patients' sera. These antibody specificities were also found in the eluates from the immunoadsorption columns. Only one patient had elevated levels of reticulated platelets. Immunoadsorption treatment did not induce a sustained increase of platelet counts in any patient. Immunoadsorption treatment in AITP can induce redistribution of antibodies into the circulation. Am.
British Journal of Haematology, 1997
Platelet‐associated and plasma autoantibodies against platelet glycoproteins (GP) have been demonstrated in patients with autoimmune thrombocytopenia (AITP) using various methods. Eight laboratories in seven countries participated in this international study to evaluate the interlaboratory agreement using glycoprotein‐specific immunoassays for these autoantibodies. The participating laboratories received blind samples of frozen washed platelets and plasma from 22 normal donors and 22 AITP patients. Platelet‐associated and plasma autoantibodies against GPIIb–IIIa and GPIb–IX were measured by MAIPA, immunobead assay or modified antigen capture assay. Of the control samples, 96.0% and 97.2% of all results for platelet‐associated and plasma autoantibodies to GPIIb–IIIa/GPIb–IX, respectively, were negative. The mean variation coefficient of the control samples of platelet‐associated and plasma autoantibodies was 89.5% (range 11.1–272.9%) and 46.5% (range 21.0–78.0%), respectively. In 20/...
Autoimmune Thrombocytopenic Purpura
Diagnostic Criteria in Autoimmune Diseases, 2008
Immune response against platelet surface antigens results in antiplatelet antibodies production, which is the basis for idiopathic (ITP), drug-induced, post transfusion, and neonatal alloimmune thrombocytopenia (NAIT), where ITP is the most common disease .
Iranian Journal of Public Health
The autoimmune disease known as Idiopathic (immune thrombocytopenic purpura thrombocytopenic purpura (ITP) is clinically defined by a low numbers of platelets in the circulation blood. This study aimed to isolate autoantibodies made against the platelet glycoproteins using platelets from healthy volunteers, to determine their specificity and further elucidate their effects on platelet function. Methods: This study used a phage display system to recognize Fab anti-platelet antibodies. Anti-platelet After isolation, the anti-platelet Fab-expressing phage was characterized by ELISA and Western blotting. The Fab-bearing phage pool obtained from five rounds of panning was analysed in order to determine its anti-platelet reactivity. Of the phage colonies obtained, 100 colonies of different sizes were randomly selected for reaction with whole platelets, using M13 phage as a negative control. Results: Twelve colonies of them had strong reactions against the whole platelet preparation, but only four colonies showed substantial reactivity against the lysed platelet preparation (lysate). Three of the four colonies showed three bands representing proteins with different molecular weights. The fourth colony showed only a single band. The final experiment to characterise the protein isolated from the phage library was a DNA gel agarose test. Conclusion: Each colony showed a DNA band that corresponded with the molecular size marker for 5.4 kbase pairs, and this suggested the presence of heavy and light antibody chains in the phage.
Clinical and Applied Thrombosis/Hemostasis, 2010
We investigated the prevalence of antinuclear antibody (ANA), thyroid antimicrosomal (AMA) and antithyroglobulin (ATA), antigliadin (AGA) immunoglobulin G (IgG)-A, anti-endomisium (EMA) IgG-A, and tissue transglutaminase (tTG) IgG-A in 87 patients with chronic idiopathic thrombocytopenic purpura (cITP) and in 95 healthy controls. Antinuclear antibody positivity was found in 13 of 87 patients and 3 of 95 controls ( P = .007). Antithyroglobulin positivity was found in 27 of patients and in 7 of the controls (P < .001). AMA positivity was found in 20 of patients and 8 of the controls (P = 0.008). Antigliadin IgG was positive in 17 patients and 1 controls (P < .001) whereas Antigliadin IgA was positive in 9 of patients and in 1 of the controls (P = .007). Anti-endomisium (IgG and IgA were not different between both groups. Tissue transglutaminase IgG was detected in 7 of patients and in 1 of the controls (P = .029). Tissue transglutaminase IgA was detected in 5 of patients and in ...
Involvement of Autoimmune Diseases in the Pathogenesis of Chronic Immune Thrombocytopenic Purpura
Journal of Biomedical Science and Engineering, 2015
Chronic immune thrombocytopenic purpura (ITP) is a condition based on an immune-mediated mechanism that determines the premature hyperdestruction of the thrombocytes in peripheral blood, as well as their deficient synthesis at the level of the bone marrow. The chronic immune purpura could be of primary, idiopathic cause, as well as of secondary cause, occurring in the context of other pathologies. The characteristic of the primary form of the disease is the presence of isolated thrombocytopenia, defined by a platelet count under 100,000/mm 3 in peripheral blood, in the absence of supporting causes for thrombocytopenia. In the secondary form of the disease, the decreased platelet count is due to associated pathologies involving an immune mechanism, responsible for the occurrence of thrombocytopenia. This study aims to emphasize the involvement of autoimmune diseases, such as systemic lupus erythematosus (SLE), dermatomyositis, rheumatoid polyarthritis or antiphospholipid syndrome in the pathogenesis of secondary thrombocytopenia. Furthermore, the study was conducted on a sample of 40 patients, divided into two groups: The first group comprising asymptomatic patients diagnosed with thrombocytopenia following routine tests, and the second group comprising patients with hemorrhagiparous symptomatology (petechiae, ecchymoses, epistaxis, gingivorrhagia), who went to the doctor in order to determine the etiology of the hemorrhagiparous syndrome. The average value of the thrombocytopenia of the patients included in the study was of 60.20 ± 19.75 × 10³/μL. Laboratory investigations performed in order to establish the etiology of thrombocytopenia showed that 80% of patients presented positive antiplatelet antibodies. Moreover, 20% of the patients in the study showed positive anti-double-stranded DNA, 20% were identified with IgG anticardiolipin antibodies, while antinuclear antibodies were present in 10% of the patients.
Annals of Hematology, 1996
In chronic idiopathic thrombocytopenic purpura (ITP) platelet destruction is caused by antibodies directed against plate][et membrane glycoproteins (GP), and the predominant autoantigens are known to be GPIb/IX and GPIIb/IIIa. In a recent study we reported that these antibodies frequently had a restricted light chain phenotype, thereby supporting a clonal origin. Similar findings and the presence of clonal B-cell populations in immune thrombocytopenias have been reported by others. In the present study we further explored the hypothesis of clonal B-cell expansions in chronic ITP. Twenty patients with chronic ITP were investigated. Antibodies were detected with an ELISA (MAIPA) specific for GPIb/IX and GPIIb/IIIa; circulating clonal B lymphocytes were assessed by flow-cytometric (FACS) clonal-excess analysis and by analyzing Ig-gene rearrangements (CDR3) with the PCR technique. Nine patients displayed a GP-specific antibody restricted to either kappa or lambda phenotype. However, FACS analysis and Ig-gene rearrangement studies did not disclose any circulating clonal B-cell population. Considering the sensitivity of the FACS analysis and Ig-gene rearrangement for detection of clonal B-cell populations, the hypothesis of clonally derived autoantibodies in ITP is still valid. Most probably, the clonal B-cell expansion responsible for the production of autoantibodies in ITP, if present, is below the detection limit for the techniques employed.