Mannose binding lectin and FcgammaRIIa (CD32) polymorphism in Spanish systemic lupus erythematosus patients

OBJECTIVE: Mannose binding lectin (MBL) and FcgammaRII (CD32) polymorphisms have both been implicated as candidate susceptibility genes in systemic lupus erythematosus (SLE). The aim of this study was to evaluate the relationship of these polymorphisms with SLE. METHODS: We studied a cohort of 125 SLE patients from Barcelona, Spain and 138 geographically matched controls. Sequence-specific primer-polymerase chain reaction (SSP-PCR) amplification was used to determine CD32 and MBL structural polymorphisms. MBL haplotypes were established using sequence-specific oligonucleotide probing techniques. RESULTS: Patients carried the MBL codon 54 mutant allele more frequently than controls [odds ratio (OR) 2.2; 95% confidence interval (CI) 1.2-4.0; P=0.007] and the haplotype HY W52 W54 W57 was found to be significantly lower in cases compared with controls (OR 0.6; 95% CI 0.4-0.9; P=0.016). CONCLUSION: The MBL gene codon 54 mutant allele appears to be a risk factor for SLE, whilst haplotypes encoding for high levels of MBL are protective against the disease. Differences between controls and patients were not significant when considering the FcgammaRIIa polymorphisms; similar results were observed for renal affectation.     

Mannose-binding lectin 2 gene haplotype analysis in Korean patients with ankylosing spondylitis

Mannose-binding lectin (MBL) serum levels or genetic polymorphisms are known to be associated with autoimmune diseases. We investigated MBL2 genetic polymorphisms in 95 patients with ankylosing spondylitis (AS) and in 252 healthy controls. MBL2 promoter polymorphisms at ?550 (H/L), ?221 (Y/X), +4 (P/Q), and exon polymorphisms at codon 52 (Arg/Cys), 54 (Gly/Asp, or A/B), and 57 (Gly/Glu) were investigated using polymerase chain reaction and restriction fragment length polymorphism. Genetic polymorphisms were analyzed using SPSS (ver 12.0) and Haploview (ver 4.2). MBL2 single-nucleotide polymorphisms (SNPs) were not significantly different between patients with AS and controls. By haplotype analysis, LYPB frequency was significantly lower in AS (10.7% vs. 21.3%, OR 0.441, 95% CI: 0.266–0.733, P value?=?0.001, Pc value?=?0.008). The frequency of LYPA (15.4% vs. 9.2%, OR 1.802, 95% CI: 1.097–2.961, P value?=?0.019, Pc value?=?0.101) and HYPB (3.5% vs. 0.8%, OR 4.457, 95% CI: 1.289–15.409, P value?=?0.011, Pc value?=?0.060) tended to be higher in AS. Clinical characteristics of AS were not associated with any MBL2 SNP or haplotype. In summary, haplotypes of MBL2 genetic polymorphisms were found to be associated with AS, which suggests that MBL2 genetic polymorphisms may play a role during the development of AS.     

The mannose-binding lectin gene polymorphisms and systemic lupus erythematosus: two case-control studies and a meta-analysis

OBJECTIVE: Mannose-binding lectin (MBL) enhances opsonization and activates complement. Dysfunctional alleles of MBL have been associated with low plasma concentrations of MBL and increased risk of systemic lupus erythematosus (SLE), but genotyping studies have shown inconsistent results. We performed case-control studies of the MBL polymorphisms in 2 Caucasian cohorts and a meta-analysis incorporating all published results of MBL genotyping in SLE to explore whether the MBL functional variants are associated with SLE. METHODS: MBL genotypes at 7 single-nucleotide polymorphisms were sequenced in 96 European American patients with SLE and 96 age-, race-, and sex-matched controls. MBL codons 52, 54, and 57 were genotyped in 285 German patients with SLE and 200 race-matched controls. Allele frequencies of all known variants were tallied for meta-analysis. RESULTS: Although there was a trend toward association with MBL polymorphisms in both patient cohorts evaluated, none of them was significantly associated with SLE on its own. Seventeen comparisons from 15 studies were included in the meta-analysis. Publication bias was excluded by Egger's regression test (P = 0.14). The overall odds ratio for MBL codon 54 variant B was 1.406 (95% confidence interval 1.221-1.608; P < 0.001). Stratification by ethnicity showed significantly increased odds ratios for association of the MBL codon 54 B variant with SLE in African, Asian, and Caucasian cohorts. CONCLUSION: Meta-analysis of all available studies on MBL polymorphisms and SLE shows that MBL variant alleles such as MBL exon 1 codon 54 B, promoter -550 L, and promoter -221 X are SLE risk factors. This association is robust and persists after incorporation of data from our 2 cohorts in which the association failed to reach significance.     

Mannan-binding lectin and complement C4A in Icelandic multicase families with systemic lupus erythematosus

OBJECTIVE: To determine whether low mannan-binding lectin (MBL) and C4A null alleles (C4AQ0) are associated with systemic lupus erythematosus (SLE) in multicase families with SLE. METHODS: Low MBL level was determined by measuring serum levels and by genotyping for mutant structural (B/C/D, designated as 0) and promoter (LX) alleles (by real-time polymerase chain reaction). C4AQ0 was detected by protein electrophoresis and corroborated with haplotype and genotype analysis. In nine Icelandic families, 24 patients with SLE were compared with 83 first-degree and 23 second-degree relatives without SLE. Twenty four unrelated family members and a population group of 330 Icelanders served as controls. RESULTS: Overall, the frequency of low MBL genotypes (0/0, LX/0 and wild-type/0) tended to be higher in patients with SLE than in their first-degree and second-degree relatives (p = 0.06), but the frequency was similar in the families and in the controls (p = 0.6). The frequency of C4AQ0 was, however, increased in patients and their relatives compared with that in the controls (p = 0.04). The combination of low MBL genotypes and C4AQ0 was found more often in the patients than in their relatives (p = 0.03) and controls (p = 0.02). However, low MBL level was observed only in patients and first-degree relatives in five of the nine multicase families. In these five families, patients with SLE had low MBL genotypes more often (64%) than their first-degree (38%) and second-degree (0%) relatives (p = 0.001), and the patients with SLE also had, accordingly, lower MBL levels than their relatives (p = 0.001). CONCLUSIONS: These findings indicate that low MBL levels can predispose people to SLE and highlight the genetic heterogeneity of this disease.     

Mannose-binding lectin and rheumatoid arthritis in southern Chinese

OBJECTIVE: Insufficiency of mannose-binding lectin (MBL) is associated with recurrent infections. Rheumatoid arthritis (RA) may represent an aberrant immune response to infections. This study examined the phenotypic expression and variant alleles of the MBL gene and its etiologic role in Chinese with RA. METHODS: We studied 211 RA patients and 196 healthy subjects. Serum MBL concentrations and codon-54 mutation of the MBL gene and its promoter polymorphisms were analyzed. Clinical characteristics and disease activity were also examined. RESULTS: Patients with RA had significantly lower serum MBL levels and higher frequency of codon-54 mutation of the MBL gene compared with controls. Additionally, there was a significant difference in the distribution of promoter polymorphisms, H/L, between RA patients and controls, although the frequencies of Y/X and those of nonstructural polymorphisms, P/Q, did not differ between the 2 groups. Furthermore, patients with RA had a lower incidence of the highest-producing haplotype HY and a higher incidence of the lowest-producing haplotype LX compared with controls. Serum MBL levels did not correlate with drug treatment or with disease activity. However, patients with erosive and serious extraarticular disease had significantly lower serum MBL levels than those without these disease manifestations at the time of study. Also, significantly more patients with erosive disease had a codon-54 mutation of the MBL gene compared with those with nonerosive disease. CONCLUSION: The codon-54 mutation and low-producing promoter polymorphisms of the MBL gene are associated with RA. A low serum level of MBL predisposes to the development of RA and is a risk factor for severe disease in southern Chinese.     

Mannose-binding lectin is a disease-modifying factor in North American patients with systemic lupus erythematosus

OBJECTIVE: To investigate whether development of systemic lupus erythematosus (SLE), its clinical manifestations, and autoantibody production are associated with polymorphisms of the mannose-binding lectin (MBL) gene in North American patients with SLE. METHODS: MBL gene polymorphisms in codons 52 (designated variant D, with the wild-type designated A), 54 (variant B), and 57 (variant C) were determined by polymerase chain reaction-sequence specific priming in 130 patients with SLE and 142 healthy controls. Autoantibodies against double-stranded DNA (dsDNA), Smith antigen, phospholipids, Ro/SSA, La/SSB, and RNP were tested at certified clinical pathology laboratories. RESULTS: A statistically significant increased likelihood of anti-Smith antibody production was observed in SLE patients with the heterozygous A/B genotype [odds ratio (OR) 5.1; 95% confidence interval (CI) 1.6-16.6; the A/A genotype as the reference group] or A/C genotype (OR 8.2; 95% CI 2.0-33.9). SLE patients with the homozygous or compound heterozygous variant genotype (O/O; O, a common designation for variant alleles) had an increased likelihood of mounting autoantibody responses against dsDNA, Ro/SSA, and La/SSB, and were more likely to have a history of renal disease (OR 4.8; 95% CI 0.9-25.2). However, differences in the frequencies of MBL variant alleles and genotypes observed between patients with SLE and controls did not reach statistical significance. CONCLUSION: A significantly increased prevalence of anti-Smith antibody was associated with the heterozygous genotypes A/B and A/C. Although MBL structural gene polymorphism was not a risk factor for SLE development in this study population, homozygosity of MBL variant alleles may be a weak disease-modifying factor, particularly for renal involvement, in North American patients with SLE.     

Antibodies to mannose binding lectin in patients with systemic lupus erythematosus

Deficiency of mannose binding lectin (MBL), a C-type lectin with structural similarities to C1q, has been shown to predispose to the development of systemic lupus erythematosus (SLE). Some patients have low serum MBL levels which cannot be explained by either structural gene mutations or promoter polymorphisms. The objective of this study was to detect the presence of autoantibodies against MBL and to evaluate their relationship to serum MBL levels. Anti-MBL antibodies of IgM and IgG classes from consecutive SLE patients (n = 135) and healthy subjects (n = 50) were measured by an in-house ELISA. Using the 90th percentile of controls as a cutoff, more SLE patients [23.7% (32/135)] were found to have IgG anti-MBL antibodies than normal controls [10.0% (5/50)] (P = 0.04). The same trend was observed when ethnicity was taken into account by analysing Caucasians alone (n = 90). IgM anti-MBL antibodies were only found in two SLE patients (2/22, 9.1%) who had no concomitant IgG anti-MBL antibodies. Serum levels of IgG anti-MBL antibodies were found to correlate with serum MBL levels (r = 0.55, P = 0.049). However, the levels of anti-MBL antibodies did not correlate with overall disease activity. Thus the production of anti-MBL antibodies is likely to be a specific antigen-driven process. Its role in lupus pathogenesis remains to be elucidated.     

The mannose‐binding lectin gene polymorphisms and systemic lupus erythematosus: Two case–control studies and a meta‐analysis

Objective

Mannose‐binding lectin (MBL) enhances opsonization and activates complement. Dysfunctional alleles of MBL have been associated with low plasma concentrations of MBL and increased risk of systemic lupus erythematosus (SLE), but genotyping studies have shown inconsistent results. We performed case–control studies of the MBL polymorphisms in 2 Caucasian cohorts and a meta‐analysis incorporating all published results of MBL genotyping in SLE to explore whether the MBL functional variants are associated with SLE.

Methods

MBL genotypes at 7 single‐nucleotide polymorphisms were sequenced in 96 European American patients with SLE and 96 age‐, race‐, and sex‐matched controls. MBL codons 52, 54, and 57 were genotyped in 285 German patients with SLE and 200 race‐matched controls. Allele frequencies of all known variants were tallied for meta‐analysis.

Results

Although there was a trend toward association with MBL polymorphisms in both patient cohorts evaluated, none of them was significantly associated with SLE on its own. Seventeen comparisons from 15 studies were included in the meta‐analysis. Publication bias was excluded by Egger's regression test (P = 0.14). The overall odds ratio for MBL codon 54 variant B was 1.406 (95% confidence interval 1.221–1.608; P < 0.001). Stratification by ethnicity showed significantly increased odds ratios for association of the MBL codon 54B variant with SLE in African, Asian, and Caucasian cohorts.

Conclusion

Meta‐analysis of all available studies on MBL polymorphisms and SLE shows that MBL variant alleles such as MBL exon 1 codon 54 B, promoter –550 L, and promoter –221 X are SLE risk factors. This association is robust and persists after incorporation of data from our 2 cohorts in which the association failed to reach significance.

     

The role of mannose-binding lectin in systemic lupus erythematosus

Susceptibility to systemic lupus erythematosus (SLE) is associated with genetic, hormonal, immunological, and environmental factors. Many genes have been related with the appearance of SLE, including several loci that code different complement components and their receptors. Some genetic deficiencies of complement molecules are strongly associated with SLE, probably because these deficiencies could cause decreased clearance of apoptotic cell material. As a consequence of the apoptotic material accumulation, high levels of autoantigens can be presented inappropriately to the immune system in an inflammatory context, resulting in an imbalance on the mechanisms of immunological tolerance, immune system activation, and autoantibody production. Recent studies proposed a role to the mannose-binding lectin (MBL) in the SLE physiopathogenesis. This protein activates the complement system, and the presence of several polymorphisms at the promoter and coding regions of the MBL-2 gene determines alterations at the plasma levels of MBL. Some of these polymorphisms have been associated with SLE susceptibility, as well as with clinical and laboratory typical features of this disease, cardiovascular events, and infections. Besides, it has been described that the presence of anti-MBL autoantibodies in sera of SLE patients can influence MBL plasma levels and its functional activity.     

Clinical and genetic risk factors for pneumonia in systemic lupus erythematosus

OBJECTIVE: To define the contribution of polymorphisms in genes encoding tumor necrosis factor (TNF), mannose-binding lectin (MBL), and Fcgamma receptor IIa (FCGR2A) as well as clinical factors, to the development of pneumonia in patients with systemic lupus erythematosus (SLE). METHODS: We studied 282 SLE patients from a multiethnic cohort. Pneumonia events and clinical risk factors for pneumonia were identified through medical record review. Genotyping was performed for MBL (+223, +230, and +239), TNF (-308, -238, and +488), and FCGR2A (-131H/R) polymorphisms. Univariate analyses were performed to identify clinical and genetic risk factors for pneumonia. Covariates for multivariate analysis included sex, ethnicity, treatment with immunomodulators, and leukopenia. RESULTS: Forty-two patients (15%) had at least 1 episode of pneumonia. Polymorphism of the TNF gene, particularly the -238A allele and a related haplotype, revealed the most striking and consistent association with pneumonia in univariate analyses. Results of multivariate analyses indicated an odds ratio (OR) for the TNF -238A allele of 3.5 (P = 0.007) and an OR for the related haplotype of 5.4 (P = 0.001). Male sex, treatment with immunomodulators, and leukopenia also influenced the risk of pneumonia. CONCLUSION: These findings suggest that specific TNF variants may identify SLE patients who are at particularly high risk of developing pneumonia. Given the prevalence and excessive morbidity associated with pneumonia in SLE, these findings have clinical relevance and provide insight into the pathogenesis.     

Mannose-binding lectin and susceptibility to infection in Chinese patients with systemic lupus erythematosus

OBJECTIVE: To test the hypothesis that low serum mannose-binding lectin (MBL) levels, as a result of the single-nucleotide polymorphisms in the promoter region (-221 X/Y) and exon 1 (codon 54 A/B) of the MBL2 gene, predispose to infection in Chinese patients with systemic lupus erythematosus (SLE). METHODS: Two hundred forty-five patients with SLE were prospectively followed for the development of major infective episodes that required hospitalization and antibiotic treatment during 1992-2005. MBL genotypes were determined by polymerase chain reaction and serum MBL levels were measured by ELISA. RESULTS: In total, 254 major infections developed in 130 patients. Serum MBL levels were shown to correlate inversely with the number of bacterial infections (r = -0.13, p = 0.03). The distribution of MBL genotypes was similar in patients with and without major infection (p = 0.84). Patients with major infection also had more major lupus exacerbations that required daily prednisolone dose > or = 15 mg. Logistic regression showed that log MBL level (odds ratio 0.516, 95% confidence interval 0.305-0.873; p = 0.01) and major lupus exacerbation (OR 1.382, 95% CI 1.154-1.654; p < 0.001) were independent risk factors to major bacterial infection after adjustment for age and disease duration. Multiple regression analysis showed an increase in risk of bacterial infection by 34.2% for every decrease in serum MBL level by one log, and by 22.8% for each increase in number of major lupus exacerbations. CONCLUSION: Low serum MBL level predisposes Chinese patients with SLE to more major infections, in particular bacterial ones.     

A study on anti-mannose binding lectin (anti-MBL) antibodies and serum MBL levels in Indian systemic lupus erythematosus patients

Systemic lupus erythematosus (SLE) is a prototype autoimmune disease characterized by systemic inflammation and autoantibody production. Anti-MBL autoantibodies have been studied in SLE for their possible effect on MBL levels and functional activity. This study aimed at detection of anti-MBL autoantibodies in Indian SLE patients and evaluates their relationship with related immunological parameters. Two hundred diagnosed SLE patients from Western India were included in the study where 87 patients were lupus nephritis (LN) (43.5 %) and remaining (56.5 %) were non-LN. Disease activity was assessed using the Systemic Lupus Erythematosus Disease Activity Index (SLEDAI). Anti-MBL autoantibodies to IgG and IgM isotypes, anti-C1q autoantibodies, MBL levels and circulating immune complex levels were detected by ELISA. C3, C4 and CRP levels were detected by nephelometer. Anti-MBL autoantibodies were detected in 52 % SLE patients, where 55 % had IgG-anti-MBL, 33.8 % had IgM-anti-MBL and 11.3 % had both subclasses. Low MBL levels were present in 64.4 % anti-MBL positives as compared with 61.5 % in anti-MBL negatives. Among anti-MBL positives, 74 % had anti-C1q antibodies, whereas 41.7 % of anti-MBL negatives had anti-C1q autoantibodies (p = 3.45E06). An inverse correlation was observed between serum MBL and CIC levels. A statistically significant difference was noted between anti-MBL positives and anti-MBL negative patients with hsCRP levels (p = 0.002). Occurrence of infections was higher among anti-MBL positives (65 %) as compared with anti-MBL negatives (35 %). The difference between SLEDAI scores among anti-MBL positive and negative groups was statistically insignificant. Anti-MBL autoantibodies in SLE patients can influence functional activity of MBL and have a significant role in SLE disease pathogenesis.     

A study on anti-mannose binding lectin (anti-MBL) antibodies and serum MBL levels in Indian systemic lupus erythematosus patients

Systemic lupus erythematosus (SLE) is a prototype autoimmune disease characterized by systemic inflammation and autoantibody production. Anti-mannose binding lectin (anti-MBL) autoantibodies have been studied in SLE for their possible effect on mannose binding lectin (MBL) levels and functional activity. This study aimed at the detection of anti-MBL autoantibodies in Indian SLE patients and evaluates their relationship with related immunological parameters. Two hundred diagnosed SLE patients from Western India were included in the study where 87 patients were lupus nephritis (LN) (43.5 %) and remaining (56.5 %) were non-LN. Disease activity was assessed using the Systemic Lupus Erythematosus Disease Activity Index (SLEDAI). Anti-MBL autoantibodies to IgG and IgM isotypes, anti-C1q autoantibodies, MBL levels and circulating immune complex levels were detected by ELISA. C3, C4 and CRP levels were detected by nephelometer. Anti-MBL autoantibodies were detected in 52 % SLE patients, where 55 % had IgG-anti-MBL, 33.8 % had IgM-anti-MBL and 11.3 % had both subclasses. Low MBL levels were present in 64.4 % anti-MBL positives as compared to 61.5 % in anti-MBL negatives. Among anti-MBL positives, 74 % had anti-C1q antibodies, whereas 41.7 % of anti-MBL negatives had anti-C1q autoantibodies (p = 3.45E06). An inverse correlation was observed between serum MBL and CIC levels. A statistically significant difference was noted between anti-MBL positives and anti-MBL negative patients with hsCRP levels (p = 0.002). Occurrence of infections was higher among anti-MBL positives (65 %) as compared to anti-MBL negatives (35 %). The difference between SLEDAI scores among anti-MBL-positive and anti-MBL-negative groups was statistically insignificant. Anti-MBL autoantibodies in SLE patients can influence functional activity of MBL and have a significant role in SLE disease pathogenesis.     

Association of mannose-binding lectin gene polymorphisms with antiphospholipid syndrome, cardiovascular disease and chronic damage in patients with systemic lupus erythematosus

OBJECTIVE: To investigate the association of mannose-binding lectin (MBL)-deficient genotypes with cardiovascular disease in a large series of patients with systemic lupus erythematosus (SLE). METHODS: A total of 114 patients diagnosed with SLE were included in the study. MBL polymorphisms were investigated by sequencing-based DNA typing of the promoter and exon 1 of the MBL2 gene. The genotypes 0/0, 0/XA and XA/XA were considered as MBL-low genotypes. RESULTS: A higher prevalence of cardiovascular disease was observed in patients carrying MBL-low genotypes compared with those carrying MBL-high genotypes [30 vs 9%, P = 0.012, odds ratio (OR) 4.54, 95% confidence interval (CI) 1.20-16.46]. Patients with MBL-low genotypes also presented higher mean values for total cholesterol (228.6 vs 202.3 mg/dl, P = 0.017) and low-density lipoprotein (LDL) cholesterol (139.9 vs 121.9 mg/dl, P = 0.045), a higher frequency of chronic renal failure (30 vs 4%, P = 0.001), vasculitis (30 vs 11%, P = 0.043), heart valve lesions (71 vs 32%, P = 0.026), cardiac valve dysfunction (57 vs 7%, P = 0.0004) and associated APS (39 vs 12%, P = 0.005), a higher mean Systemic Lupus International Collaborating Clinics score (2.09 vs 1.26, P = 0.029) and a lower prevalence of low C4 levels (43 vs 71%, P = 0.015). Multivariate analysis of genetic, clinical and immunological variables showed that only antiphospholipid syndrome (APS) was independently associated with cardiovascular events (P = 0.001). CONCLUSION: Although the prevalence of cardiovascular disease in our SLE patients carrying MBL-deficient genotypes was 3.3 times higher than in patients with non-deficient genotypes, only APS was independently associated with cardiovascular events. This suggests that the higher frequency of thrombotic events in SLE patients carrying MBL-deficient genotypes might be related to coexisting APS.     

Variant mannose-binding lectin 2 genotype is a risk factor for reactive systemic amyloidosis in rheumatoid arthritis

OBJECTIVE: The aim of this study was to investigate whether polymorphism of the mannose-binding lectin 2 (MBL2) gene is related to the occurrence of systemic AA amyloidosis in patients with rheumatoid arthritis (RA). METHODS: MBL2 structural gene polymorphisms at codon 52 (CGT-->TGT, Arg-->Cys; D), codon 54 (GGC-->GAC, Gly-->Asp; B) and codon 57 (GGA-->GAA, Gly--> Glu; C), and MBL2 promoter region polymorphism at position -221 (G-->C) were examined in 57 patients with RA complicated by biopsy-proven reactive amyloidosis and 51 control RA patients without amyloid. RESULTS: A strong association was found between the presence of a structural MBL2 gene variant O (B, D or C) and the occurrence of amyloidosis in RA patients: 29 of 57 (50.9%) of the RA patients with amyloid had a variant allele compared with 12 of 51 (23.5%) of the RA patients without amyloid (OR 3.37, 95% CI 1.47-7.72; P = 0.004). CONCLUSION: We conclude that variant MBL2 structural genotype constitutes a significant risk factor for reactive amyloidosis in RA and that the increased risk is probably related to MBL-mediated impairment of mononuclear phagocyte function.     

Mannose-binding lectin polymorphisms in patients with hepatitis C virus infection

BACKGROUND: Persistent infection with hepatitis C virus (HCV) leads to liver cirrhosis (LC) and often to liver cancer. Little is known about host factors that determine the variable natural history. Mannose-binding lectin (MBL) is an important constituent of the innate immune system. In white patients there is an association between codon 52 mutation of the MBL gene and persistent hepatitis B virus (HBV) infection. To determine whether MBL gene polymorphisms affect the course of HCV infection, we investigated the association between MBL gene polymorphisms and HCV infection in Japanese subjects. METHODS: Fifty-two HCV-infected Japanese patients (8 with chronic inactive hepatitis (CIH), 31 with chronic active hepatitis (CAH), 13 with LC) and 50 normal controls were studied. MBL gene mutations were determined by means of polymerase chain reaction and restriction fragment length polymorphism analyses. RESULTS: Codon 52 and codon 57 mutations were absent in all subjects. Homozygous mutation in codon 54 was present in one (0.9%) patient. Heterozygous codon 54 mutation was present in 17 (32%) of the 52 patients and in 21 (41%) of the controls. No significant difference in the frequency of codon 54 mutation was observed between patient and control groups. However, although no significant relationship was observed between MBL polymorphisms and the levels of HCV RNA, all patients with heterozygous or homozygous codon 54 mutations had CAH or LC. In contrast, 8 of the 34 patients without codon 54 mutation remained at CIH. (P = 0.0405). CONCLUSION: MBL may be one of the factors that influence the course of HCV infection.     

Mannose-Binding Lectin Polymorphisms in Patients with Hepatitis C Virus Infection

Background: Persistent infection with hepatitis C virus (HCV) leads to liver cirrhosis (LC) and often to liver cancer. Little is known about host factors that determine the variable natural history. Mannose-binding lectin (MBL) is an important constituent of the innate immune system. In white patients there is an association between codon 52 mutation of the MBL gene and persistent hepatitis B virus (HBV) infection. To determine whether MBL gene polymorphisms affect the course of HCV infection, we investigated the association between MBL gene polymorphisms and HCV infection in Japanese subjects. Methods: Fifty-two HCV-infected Japanese patients (8 with chronic inactive hepatitis (CIH), 31 with chronic active hepatitis (CAH), 13 with LC) and 50 normal controls were studied. MBL gene mutations were determined by means of polymerase chain reaction and restriction fragment length polymorphism analyses. Results: Codon 52 and codon 57 mutations were absent in all subjects. Homozygous mutation in codon 54 was present in one (0.9%) patient. Heterozygous codon 54 mutation was present in 17 (32%) of the 52 patients and in 21 (41%) of the controls. No significant difference in the frequency of codon 54 mutation was observed between patient and control groups. However, although no significant relationship was observed between MBL polymorphisms and the levels of HCV RNA, all patients with heterozygous or homozygous codon 54 mutations had CAH or LC. In contrast, 8 of the 34 patients without codon 54 mutation remained at CIH. (P = 0.0405). Conclusion: MBL may be one of the factors that influence the course of HCV infection.     

Mannose-binding lectin (MBL) codon 54 (rs1800450) polymorphism predisposes towards medium vessel vasculitis in patients with systemic lupus erythematosus

Systemic lupus erythematosus (SLE) is a systemic autoimmune disease with multiple etiological factors. Mannose-binding lectin (MBL) plays a key role in innate immunity by activating antibody-independent lectin complement pathway, opsonisation, phagocytosis, and immune complex (IC) clearance. Genetic polymorphisms in the promoter and coding regions of MBL gene affect the circulatory levels and biological activity of MBL. Defects in MBL can lead to defective opsonisation and, hence, hamper clearance of apoptotic debris, the persistence of which can drive autoantibody formation in lupus. The exon1 variants at codon 52, 54, and 57 have been reported to augment the risk of SLE in different ethnic populations. Three hundred South Indian Tamil patients with SLE and 460 age-, sex-, and ethnicity-matched controls were genotyped for three polymorphisms at codon 52, 54, and 57 in exon1 of MBL gene by Taqman real-time PCR. The three polymorphisms in exon1 of MBL were observed not to confer risk of developing SLE. However, MBL codon 54 rs1800450 polymorphism was associated with the development of medium vessel vasculitis and gangrene (OR-2.29, CI 95% 1.08–4.83, p = 0.02), whereas, the ancestral allele G conferred protection (OR-0.44, CI 95% 0.21–0.93, p = 0.02). Genetic variants in the exon1 of MBL gene per se are not risk factors for SLE in South Indian Tamils. However, the association of codon 54 (rs1800450) with medium vessel vasculitis suggests that it may be a genetic modifier of clinical phenotype in SLE.     

Presence of Idiopathic Thrombocytopenic Purpura and autoimmune hemolytic anemia in the patients with common variable immunodeficiency

Common Variable Immunodeficiency (CVID) is a heterogeneous group of disorders characterized by hypogammaglobulinemia and an increased susceptibility to recurrent infections as well as autoimmunity and malignancies. Idiopathic Thrombocytopenic Purpura (ITP) and Autoimmune Hemolytic Anemia (AIHA) are two autoimmune disorders which may be seen in association with CVID. Among 85 CVID patients, seven cases had ITP and/or AIHA (8%). Four of these patients had one or more episodes of ITP, one patient had AIHA, and two patients had both ITP and AIHA (Evans syndrome). Almost, all patients experienced chronic and recurrent infections mostly in respiratory and gastrointestinal systems during the course of the disease. Among the seven patients, five presented their underlying disease with recurrent respiratory and/or gastrointestinal tract infections, while in two remaining patients, CVID was presented with ITP. Three patients died until now; two because of hepatic failure and one due to pulmonary hemorrhage. As CVID is prone to autoimmune disorders, it should be considered as a differential diagnosis of adult-onset ITP and possibly in children. Chronic and recurrent ITP, especially in the presence of propensity to respiratory and gastrointestinal infections mandate the evaluation for an underlying immune dysregulation such as CVID.