Prospective Observational Study on the Association Between Serum Mannose-Binding Lectin Levels and Severe Outcome in Critically Ill Patients with Pandemic Influenza Type A (H1N1) Infection (original) (raw)
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Frontiers in Immunology
Background: Mannose-binding lectin (MBL) is an innate immune protein with strong biologic plausibility for protecting against influenza virus-related sepsis and bacterial co-infection. In an autopsy cohort of 105 influenza-infected young people, carriage of the deleterious MBL gene MBL2_Gly54Asp("B") mutation was identified in 5 of 8 individuals that died from influenza-methicillin-resistant Staphylococcus aureus (MRSA) co-infection. We evaluated MBL2 variants known to influence MBL levels with pediatric influenza-related critical illness susceptibility and/or severity including with bacterial co-infections. Methods: We enrolled children and adolescents with laboratory-confirmed influenza infection across 38 pediatric intensive care units from November 2008 to June 2016. We sequenced MBL2 "low-producer" variants rs11003125("H/L"), rs7096206("Y/X"), rs1800450 Gly54Asp ("B"), rs1800451 Gly57Glu ("C"), rs5030737 Arg52Cys ("D") in patients and biologic parents. We measured serum levels and compared complement activity in low-producing homozygotes ("B/B," "C/C") to HYA/HYA controls. We used a population control of 1,142 healthy children and also analyzed family trios (PBAT/HBAT) to evaluate disease susceptibility, and nested case-control analyses to evaluate severity. Results: We genotyped 420 patients with confirmed influenza-related sepsis: 159 (38%) had acute lung injury (ALI), 165 (39%) septic shock, and 30 (7%) died. Although bacterial co-infection was diagnosed in 133 patients (32%), only MRSA co-infection (n = 33, 8% overall) was associated with death (p < 0.0001), present in 11 of 30 children that died (37%). MBL2 variants predicted serum levels and complement activation as expected. We found no association between influenza-related critical illness susceptibility and MBL2 variants using family trios (633 biologic parents) or compared to population controls. MBL2 variants were not associated with admission illness severity, septic shock, ALI, or bacterial co-infection diagnosis. Carriage of low-MBL producing MBL2 variants was not a risk factor for mortality, but children that died did have higher carriage of one or more B alleles (OR 2.3; p = 0.007), including 7 of 11 with influenza MRSA-related death (vs. 2 of 22 survivors: OR 14.5, p = 0.0002). Conclusions: MBL2 variants that decrease MBL levels were not associated with susceptibility to pediatric influenza-related critical illness or with multiple measures of critical illness severity. We confirmed a prior report of higher B allele carriage in a relatively small number of young individuals with influenza-MRSA associated death.
Low mannose-binding lectin function is associated with sepsis in adult patients
FEMS Immunology and Medical Microbiology, 2006
Mannose-binding lectin (MBL) is an innate immune system pattern recognition molecule that kills a wide range of pathogens via the lectin complement pathway. MBL deficiency is associated with severe infection but the best measure of this deficiency is undecided. We investigated the influence of MBL functional deficiency on the development of sepsis in 195 adult patients, 166 of whom had bloodstream infection and 35 had pneumonia. Results were compared with 236 blood donor controls. MBL function (C4b deposition) and levels were measured by enzyme-linked immunosorbent assay. Using receiver-operator characteristics of MBL function in healthy controls, we identified a level of o 0.2 U mL À1 as a highly discriminative marker of low MBL2 genotypes. Median MBL function was lower in sepsis patients (0.18 U mL À1 ) than in controls (0.48 U mL À1 , P o 0.001). MBL functional deficiency was more common in sepsis patients than controls (P o 0.001). MBL functional deficient patients had significantly higher sequential organ failure assessment (SOFA) scores and higher MBL function and levels were found in patients with SOFA scores predictive of good outcome. Deficiency of MBL function appears to be associated with bloodstream infection and the development of septic shock. High MBL levels may be protective against severe sepsis.
Mannose-binding lectin in severe acute respiratory syndrome coronavirus infection
Journal of Infectious …, 2005
Little is known about the innate immune response to severe acute respiratory syndrome (SARS) coronavirus (CoV) infection. Mannose-binding lectin (MBL), a key molecule in innate immunity, functions as an anteantibody before the specific antibody response. Here, we describe a case-control study that included 569 patients with SARS and 1188 control subjects and used in vitro assays to investigate the role that MBL plays in SARS-CoV infection. The distribution of MBL gene polymorphisms was significantly different between patients with SARS and control subjects, with a higher frequency of haplotypes associated with low or deficient serum levels of MBL in patients with SARS than in control subjects. Serum levels of MBL were also significantly lower in patients with SARS than in control subjects. There was, however, no association between MBL genotypes, which are associated with low or deficient serum levels of MBL, and mortality related to SARS. MBL could bind SARS-CoV in a dose-and calcium-dependent and mannan-inhibitable fashion in vitro, suggesting that binding is through the carbohydrate recognition domains of MBL. Furthermore, deposition of complement C4 on SARS-CoV was enhanced by MBL. Inhibition of the infectivity of SARS-CoV by MBL in fetal rhesus kidney cells (FRhK-4) was also observed. These results suggest that MBL contributes to the first-line host defense against SARS-CoV and that MBL deficiency is a susceptibility factor for acquisition of SARS.
BMC Immunology, 2010
Background: Mannose-binding lectin (MBL), a pattern recognition innate immune molecule, inhibits influenza A virus infection in vitro. MBL deficiency due to gene polymorphism in humans has been associated with infection susceptibility. These clinical observations were confirmed by animal model studies, in which mice genetically lacking MBL were susceptible to certain pathogens, including herpes simplex virus 2. Results: We demonstrate that MBL is present in the lung of naïve healthy wild type (WT) mice and that MBL null mice are more susceptible to IAV infection. Administration of recombinant human MBL (rhMBL) reverses the infection phenotype, confirming that the infection susceptibility is MBL-mediated. The anti-viral mechanisms of MBL include activation of the lectin complement pathway and coagulation, requiring serum factors. White blood cells (WBCs) in the lung increase in WT mice compared with MBL null mice on day 1 post-infection. In contrast, apoptotic macrophages (MΦs) are two-fold higher in the lung of MBL null mice compared with WT mice. Furthermore, MBL deficient macrophages appear to be susceptible to apoptosis in vitro. Lastly, soluble factors, which are associated with lung injury, are increased in the lungs of MBL null mice during IAV infection. These results suggest that MBL plays a key role against IAV infection.
Low mannose-binding lectin (MBL) levels in neonates with pneumonia and sepsis
Clinical & Experimental Immunology, 2007
Summary We investigated whether deficiency of mannose-binding lectin (MBL), a component of innate immunity, is associated with neonatal pneumonia and sepsis during the first 72 h, i.e. early onset, and during the first month after birth. In 88 neonatal intensive care patients (71 premature), MBL2 genotype and MBL plasma levels at birth were determined prospectively by Taqman analysis and enzyme-linked immunosorbent assay, respectively. Thirty-five neonates (40%) had low, i.e. ≤ 0·7 µg/ml, MBL plasma levels at birth. Median (interquartile range) MBL plasma levels in 32 no early-onset sepsis (EOS) cases, 44 possible EOS cases and 11 EOS cases were 1·57 (0·57–2·67) µg/ml, 1·05 (0·41–1·70) µg/ml and 0·20 (0·10–0·77) µg/ml, respectively (P < 0·01). During the first month, 28 neonates (32%) had no infection, 49 (55%) had suspected infection, five (6%) had pneumonia and six (7%) had culture-proven sepsis. Low MBL levels at birth were associated both with an increased risk of developing ...
Role of mannose-binding lectin in nosocomial sepsis in critically ill neonates
Human Immunology, 2010
We investigated the association of mannose-binding lectin (MBL) serum levels with nosocomial sepsis (NS), their changes overtime during infection, their relation with pathogens, with the MBL2 genotype and their relationship with mortality. In a prospective observational study, we included 365 critically ill neonates: 261 had no infection and 104 had at least 1 septic event. The median MBL serum concentration was significantly lower in infected than in noninfected neonates (p Ͻ 0.001). Low MBL levels on admission increased the risk of infection, independently from gestational age and invasive procedures. The median peak MBL level during infection was higher than the median level on admission (p Ͻ 0.001) and was correlated with it (r 2 ϭ 0.83, p Ͻ 0.001). Moreover, MBL levels on admission were not associated with death (OR ϭ 0.80, 95% CI ϭ 0.56 -1.14, p ϭ 0.21). Similarly, no association was found between MBL peak levels during infection and death among infected neonates (OR ϭ 1.10, 95% CI ϭ 0.78 -1.57, p ϭ 0.57). In 127 neonates (42 infected) genotyped for exon-1 and -221 promoter MBL2 variants, we did not find significant difference in the frequencies of MBL2 genotypes between infected and noninfected neonates. Moreover, no association was found between MBL2 genotypes and death. ᭧
Shock, 2006
Mannose-binding lectin (MBL) genetic polymorphisms result in deficiency of the encoded protein and increased susceptibility to infection, especially in children and the immunocompromised. The objective of this study was to investigate the relationship between MBL-2 exon 1 and promoter 2221 polymorphisms, plasma levels of the encoded protein, and the incidence and outcome of severe sepsis and septic shock. One hundred seventy-four white adult patients with severe sepsis or septic shock were recruited in a prospective multicenter study across eight intensive care units in the South of England, UK. Genotype and haplotype frequencies were compared between normal population controls and patients, and between survivors and nonsurvivors. Plasma levels of encoded protein were related to genotype and outcome. The exon 1 polymorphisms (A/O or O/O) were significantly more common in the patients with severe sepsis and septic shock than in normal healthy adults (54.6% vs. 39.7%, P = 0.001), and there was a significant difference in haplotype frequency between controls and septic patients (P < 0.0001). There was no significant difference in MBL-2 genotype or haplotype frequency between survivors and nonsurvivors. There was a strong relationship between MBL-2 haplotype and plasma MBL concentration (P < 0.001). Individual plasma levels were variable and increased between days 1 and 7. The mortality rate was higher in those with MBL levels <1000 mg/L than in those patients with levels >1000 mg/L (47.2 vs. 22.2%, P = 0.05). We conclude that genetic polymorphisms resulting in mannose-binding lectin deficiency are associated with increased susceptibility to sepsis. The close relationship between polymorphic variants and plasma MBL concentration persists during sepsis but individual levels vary widely. Lower circulating MBL levels are associated with a poor outcome.