Mannose-binding lectin gene: polymorphisms in Japanese patients with systemic lupus erythematosus, rheumatoid arthritis and Sjögren's syndrome

Mannose-Binding Lectin Gene Variants as Disease Susceptibility Biomarkers in Rheumatoid Arthritis

Background: Rheumatoid arthritis (RA) is a chronic, inflammatory autoimmune disease characterized by progressive destruction of peripheral joints. About 1% of the human population worldwide is suffering from this disease. The pathophysiology of RA is largely being influenced by immune dysregulation. Mannose-binding lectin (MBL), an acute-phase protein, has been reported to play an important role in pathogenesis of RA by the activation of complement pathway. Various studies documented the established the role of MBL in pathogenesis of various autoimmune diseases, including RA. MBL protein is encoded by gene MBL2, mapped on chromosome 10q11.2-q21. Objective: Both MBL serum levels and activity are mainly determined genetically by its variants. So considering the putative clinical role of MBL2, this case-control association study was designed to assess its six functional variants in a northwestern Indian cohort. Methods: Genetic typing of six MBL2 variants was done by amplification refractory mutation system-polymerase chain reaction. Data were analyzed using suitable statistical tools. Results: Significant difference has been observed in genotypic and allelic distribution between cases and controls for rs11003125. Comparison of allelic distribution for rs1800450 showed significantly high prevalence of A allele in cases than controls. Conclusion: These results indicate that MBL2 variants may act as plausible marker for susceptibility toward RA. Keeping this in view, it is pertinent to screen these variants in other population groups of India.

The complement system and human autoimmune diseases

Genetic deficiencies of early components of the classical complement activation pathway (especially C1q, r, s, and C4) are the strongest monogenic causal factors for the prototypic autoimmune disease systemic lupus erythematosus (SLE), but their prevalence is extremely rare. In contrast, isotype genetic deficiency of C4A and acquired deficiency of C1q by autoantibodies are frequent among patients with SLE. Here we review the genetic basis of complement deficiencies in autoimmune disease, discuss the complex genetic diversity seen in complement C4 and its association with autoimmune disease, provide guidance as to when clinicians should suspect and test for complement deficiencies, and outline the current understanding of the mechanisms relating complement deficiencies to autoimmunity. We focus primarily on SLE, as the role of complement in SLE is well-established, but will also discuss other informative diseases such as inflammatory arthritis and myositis.

Effect of mannose-binding lectin gene polymorphisms on the risk of rheumatoid arthritis: Evidence from a meta-analysis

BACKGROUND

The effect of mannose-binding lectin (MBL) gene polymorphisms on susceptibility of rheumatoid arthritis (RA) were evaluated in ethnically different populations, whereas the results were always inconsistent.

MATERIALS AND METHODS

Fourteen articles involving 36 datasets were recruited to evaluate the association between MBL gene polymorphisms and rheumatoid arthritis in a meta-analysis. The random or fixed effect models were used to evaluate the pooled odds ratios (ORs) and their corresponding 95% confidence intervals (CIs).

RESULTS

Stratified analysis by ethnicities was conducted and the result revealed that rs1800450 (T vs C, OR = 1.32, 95% CI: 1.04-1.67, P < .05) and MBL-A/O (T vs C, OR = 1.20, 95% CI: 1.08-1.34, P < .001) were strongly associated with RA in Brazilian populations. In addition, the significant relationship between rs11003125 (T vs C, OR = 1.16, 95% CI: 1.06-1.26, P < .05) with RA were also observed in East Asian populations. Meanwhile, the inverse associations between rs5030737 with RA in East Asians and rs1800450 with RA in Indians were acquired. However, no association between any MBL polymorphism with RA susceptibility was confirmed in Caucasians.

CONCLUSIONS

The structural polymorphisms in exon 1 of MBL gene may significantly contribute to susceptibility and development of RA in Brazilian and Indian populations, whereas the functional polymorphisms in the promoter region were more likely to associate with RA in East Asians.

Association of MBL2 gene polymorphisms and systemic lupus erythematosus susceptibility: A meta-analysis

OBJECTIVES

Mannose binding lectin (MBL) gene single nucleotide polymorphisms have been associated with systemic lupus erythematosus (SLE) risk with inconsistent results. This study aimed to explore whether MBL2 A\B, A\C, A\D, A\O, L\H and Y\X polymorphisms affected SLE susceptibility.

METHODS

A meta-analysis was performed on 20 studies, containing allelic contrast, additive, dominant and recessive models. Odds ratio (OR) was calculated to reflect the effect of association.

RESULTS

A total of 64 pooled comparisons were conducted, including 7194 SLE patients and 7401 healthy controls. The meta-analysis inducted a significant association between allele B and SLE (OR = 0.766, 95% CI = 0.681-0.862, P < .001). The genotype BB in the additive model and AB + BB in the recessive model both reduced the risk of SLE (OR = 0.611, 95% CI = 0.422-0.882, P = .009; OR = 0.806, 95% CI = 0.688-0.944, P = .008). Regarding A\O polymorphisms, results revealed statistical differences in allelic contrast, additive model and recessive models (OR = 0.826, 95% CI = 0.732-0.931, P = .002; OR = 0.737, 95% CI = 0.557-0.977, P = .034 and OR = 0.793, 95% CI = 0.683-0.921, P = .002, respectively). As for L\H, meta-analysis revealed that allele H and genotype HH both decreased SLE susceptibility in allelic contrast and dominant models (OR = 1.463, 95% CI = 1.097-2.007, P = .018; OR = 1.383, 95% CI = 1.124-1.701, P = .002). Stratification by ethnicity indicated that allele H related to SLE in European populations (OR = 0.736, 95% CI = 0.617-0.879, P = .001), and the recessive model correlated with SLE in Asians (OR = 0.808, 95% CI = 0.667-0.979, P = .03).

CONCLUSION

The present study suggests that A\B and A\O polymorphisms were associated with SLE susceptibility, and the allele H may be a protective factor in SLE.

The association of mannose binding lectin genotype and immune response to Chlamydia pneumoniae: The Strong Heart Study

Cardiovascular disease (CVD) is an important contributor to morbidity and mortality in American Indian communities. The Strong Heart Study (SHS) was initiated in response to the need for population based estimates of cardiovascular disease in American Indians. Previous studies within SHS have identified correlations between heart disease and deficiencies in mannose binding lectin (MBL), a motif recognition molecule of the innate immune system. MBL mediates the immune response to invading pathogens including Chlamydia pneumoniae (Cp), which has also been associated with the development and progression of CVD. However, a link between MBL2 genotype and Cp in contributing to heart disease has not been established. To address this, SHS collected baseline Cp antibody titers (IgA and IgG) and MBL2 genotypes for common functional variants from 553 individuals among twelve participating tribes. A single nucleotide polymorphism (SNP) in the promoter, designated X/Y, correlated significantly with increased Cp IgG titer levels, whereas another promoter SNP (H/L) did not significantly influence antibody levels to Cp. Two variants within exon 1 of MBL2, the A and B alleles, also displayed significant association with Cp antibody titers. Some MBL2 genotypes were absent from the population, suggesting linkage disequilibrium may be operating within the SHS cohort. Additional factors, such as increasing age and socioeconomic status, were also associated with increased Cp IgG antibody titers. This study demonstrates that MBL2 genotype associates with immune reactivity to C. pneumoniae in the SHS cohort. Thus, MBL2 may contribute to the progression of cardiovascular disease (CVD) among American Indians indirectly through pathogen interactions in addition to its previously defined roles.

CTLA-4 gene polymorphisms are associated with obesity in Turner Syndrome

Turner syndrome (TS) is characterized by a set of clinical conditions, including autoimmune/inflammatory diseases and infectious conditions, that can compromise a patient’s quality of life. Here we assessed polymorphisms in CTLA-4 +49A/G (rs231775), PTPN22 +1858G/A (rs2476601), and MBL2 -550 (H/L) (rs11003125), -221(X/Y) (rs7096206) and exon 1 (A/O) in women from northeastern Brazil to determine whether polymorphisms within these key immune response genes confer differential susceptibility to clinical conditions in TS. A case-control genetic association study was performed, including 86 female TS patients and 179 healthy women. An association was observed for the A/G genotype of CTLA-4 +49A/G in TS patients (p=0.043, odds ratio [OR]=0.54). In addition, an association between the CTLA-4 G/G genotype and obesity was detected in TS patients (p=0.02, OR=6.04). Regarding, the -550(H/L) polymorphism in the MBL2 promoter, the frequency of the H/L genotype was significantly higher in the TS group than healthy controls (p=0.01, OR=1.96). The H/H genotype indicated a protective effect in TS patients (p=0.01, OR=0.23). No differences were observed in the distribution of -221(X/Y), MBL2 exon 1 variants, and PTPN22 +1858G/A in any assessed groups. CTLA-4 variants are potentially involved in obesity in this cohort of TS patients from northeastern Brazil.

Association of Single-Nucleotide Polymorphisms of the MBL2 with Atopic Dermatitis in Korean Patients

BACKGROUND

Human mannose-binding lectin (MBL) is a serum lectin taking part in the innate immunity by opsonizing various microorganisms for phagocytosis. The MBL serum concentration is affected by several single-nucleotide polymorphisms (SNPs) in the promoter region of the MBL2 gene.

OBJECTIVE

The purpose of this study was to examine the relationship between MBL2 polymorphisms and atopic dermatitis (AD) susceptibility.

METHODS

To examine whether the MBL2 SNPs are related to AD susceptibility, we examined 237 patients with AD and 94 controls by polymerase chain reaction (PCR)-restriction fragment length polymorphism and PCR-sequence specific primer analyses of four polymorphic loci: two (H/L and X/Y) within the promoter region and the other two (P/Q and A/B) within exon 1. MBL concentrations in the blood were estimated by ELISA.

RESULTS

The prevalence of haplotype HYPB, leading to MBL deficiency, was significantly decreased in the AD patients compared to the controls (p=0.002), while the prevalence of haplotype HYPA was increased with a clear trend toward significance (p=0.056). The frequency of MBL2 LYPB/LXPA (odds ratio, 0.08; 95% confidence interval, 0.009~0.655; p=0.021) were significantly decreased in the AD patients. The blood log [total immunoglobulin E, IgE] levels of MBL2 HYPA/HYPA, HYPA/LYPA, HYPA/LYPB, HYPA/LYQA, and LYQA/LXPA haplotype pairs were significantly increased in the AD patients.

CONCLUSION

The frequency of MBL2 HYPB haplotype was significantly decreased in the AD patients compared to the controls. The frequency of LYPB/LXPA had a possibly protective effect on AD. Moreover, the MBL2 HYPA haplotype pairs, which were related to higher blood total IgE levels, were possibly associated with extrinsic AD.

Immunodeficiency in the lupus clinic

Systemic lupus erythematous (SLE) and immunodeficiency are linked in various ways. For example, rare genetic complement deficiencies can pre-dispose to developing SLE, whilst some treatments for SLE can cause secondary immunodeficiencies. Various case reports describe SLE patients who have concomitant or later develop antibody deficiency, possibly related to immunosuppressive treatment, or possibly related to the lupus itself. Other components of the immune system, innate and adaptive may also be affected. Immunosuppressive treatment may also cause infections in the absence of defects on routine immunological testing. It is important for the clinician to be aware of the associations between SLE and immunodeficiency to ensure optimal investigation and management. This review focuses on aspects of humoral and cellular immunity, and their association with SLE.

Mannose-binding lectin polymorphisms and rheumatoid arthritis: A short review and meta-analysis

Mannose-binding lectin (MBL) is a pattern recognition receptor of the lectin pathway of complement system. MBL binds to carbohydrates on microorganism's surfaces leading to complement activation, opsonization and phagocytosis. Polymorphisms in the MBL gene (MBL2) are associated with variations on MBL serum levels and with the susceptibility to various infectious and autoimmune diseases. The involvement of the lectin pathway in rheumatoid arthritis (RA) has been demonstrated by several studies and although MBL has been considered to have a dual role in the pathogenesis of the disease, the association between MBL and RA remains inconclusive. In an attempt to clarify this relationship, we developed this short review summarizing accumulated evidences in regard to MBL and RA and a meta-analysis to evaluate the influence of MBL2 polymorphisms on the susceptibility to RA. Among a total of 217 articles that were identified following a predefined search strategy on PubMed, Scopus, Scielo, EMBASE and Cochrane databases, only 13 met all inclusion criteria and were included in the meta-analysis. Data assessment was conducted by three independent investigators and presented in odds ratio (OR) and 95% confidence intervals (CIs) using forest plot charts. Both heterogeneity and publication bias were analyzed. The results of the meta-analysis evidenced that MBL2 low producing OO and XX genotypes do not confer higher risk to RA, even when data were analyzed according to cohort's ethnicity. Further studies are needed in order to clarify the importance of other genes of the lectin pathway in the pathogenesis of RA.

MBL-2 polymorphisms (codon 54 and Y-221X) and low MBL levels are associated with susceptibility to multi organ dysfunction in P. falciparum malaria in Odisha, India

Background: Mannose binding lectin, a plasma protein protects host from virus, bacteria, and parasites. Deficiency in MBL levels has been associated with susceptibility to various infectious diseases including P. falciparum malaria. Common MBL polymorphisms in promoter and coding regions are associated with decrease in plasma MBL levels or production of deformed MBL, respectively. In the present study, we hypothesized that MBL2 variants and plasma MBL levels could be associated with different clinical phenotypes of severe P. falciparum malaria.

Methods: A hospital based study was conducted in eastern Odisha, India which is endemic to P. falciparum malaria. Common MBL-2 polymorphisms (codon 54, H-550L, and Y-221X) were typed in 336 cases of severe malaria (SM) [94 cerebral malaria (CM), 120 multi-organ dysfunction (MOD), 122 non-cerebral severe malaria (NCSM)] and 131 un-complicated malaria patients (UM). Plasma MBL levels were quantified by ELISA.

Results: Severe malaria patients displayed lower plasma levels of MBL compared to uncomplicated falciparum malaria. Furthermore, on categorization of severe malaria patients into various subtypes, plasma MBL levels were very low in MOD patients compared to other categories. Higher frequency of AB genotype and allele B was observed in MOD compared to UM (AB genotype: P = 0.006; B allele: P = 0.008). In addition, prevalence of YX genotype of MBL Y-221X polymorphism was also statistically more frequent in MOD case than UM (P = 0.009).

Conclusions: The observations of the present study reveal that MBL-2 polymorphisms (codon 54 and Y-221X) and lower plasma MBL levels are associated with increased susceptibility to multi organ dysfunctions in P. falciparum malaria.

Meta-analysis of functional MBL polymorphisms. Associations with rheumatoid arthritis and primary Sjögren's syndrome

OBJECTIVE

The aim of this study was to determine whether functional mannose-binding lectin gene (MBL) polymorphisms are associated with the susceptibility to rheumatoid arthritis (RA) or primary Sjögren's syndrome (pSS).

METHODS

A meta-analysis was conducted to investigate the potential association of RA or pSS with MBL polymorphisms, including the codon 54 (allele B), codon 57 (allele C), and codon 52 (allele D) variants of exon 1, and the - 550 (allele L) and - 221 (allele X) promoter variants.

RESULTS

A total of 12 comparative studies, including eight RA (1623 patients and 1671 controls) and four pSS (280 patients and 516 controls) studies, were included in the meta-analysis. The meta-analysis revealed no association between the MBL B allele and RA in the overall study population (odds ratio [OR] 0.991, 95 % confidence interval [CI] 0.726-1.355, p = 0.957). However, the meta-analysis showed significant associations between the MBL D, H, and X alleles and RA in the overall population (OR 1.708, 95 % CI 1.077-2.707, p = 0.023; OR 1.936, 95 % CI 1.218-3.078, p = 0.005; OR 1.582, 95 % CI 1.216-2.057, p = 0.001, respectively). An association was found between the MBL B allele and pSS in the overall study population (OR 0.691, 95 % CI 0.541-0.917, p = 0.010). Stratification by ethnicity indicated a trend toward an association between the B allele and pSS in European populations, but no association in Asian populations (OR 0.689, 95 % CI 0.465-1.021, p = 0.063; OR 0.896, 95 % CI 0.311-2.562, p = 0.838, respectively).

CONCLUSION

This meta-analysis demonstrated an association between the MBL D, L, and X alleles and the risk of RA. It also demonstrated an association between the MBL B allele and the susceptibility to pSS, suggesting a protective role of the MBL B allele against the development of pSS.

Mannose binding lectin: a biomarker of systemic lupus erythematosus disease activity

Introduction

A role for mannose binding lectin (MBL) in autoimmune diseases has been demonstrated earlier and elevated level of MBL has been shown in systemic lupus erythematosus (SLE) patients. In the current study, we investigated MBL as a potential biomarker for disease activity in SLE.

Methods

In a case control study SLE patients (93 females) and 67 age, sex, ethnicity matched healthy controls were enrolled. Plasma MBL levels were quantified by enzyme linked immunosorbent assay (ELISA). Clinical, serological and other markers of disease activity (C3, C4 and anti-dsDNA) were measured by standard laboratory procedures.

Results

Plasma MBL levels were significantly high in SLE patients compared to healthy controls (P < 0.0001). MBL levels were variable in different clinical categories of SLE. Lower levels were associated with musculoskeletal and cutaneous manifestations (P = 0.002), while higher and intermediate MBL levels were significantly associated with nephritis in combination with other systemic manifestations (P = 0.01 and P = 0.04 respectively). Plasma MBL correlated with systemic lupus erythematosus disease activity index (SLEDAI) (P = 0.0003, r = 0.36), anti-dsDNA (P < 0.0001, r = 0.54), proteinuria (P < 0.0001, r = 0.42) and negatively correlated with C3 (P = 0.007, r = -0.27) and C4 (P = 0.01, r = -0.29).

Conclusions

Plasma MBL is a promising marker in the assessment of SLE disease activity.

Low producer MBL genotypes are associated with susceptibility to systemic lupus erythematosus in Odisha, India

Variants of MBL gene have been associated with autoimmune disorders. The aim of this study was to explore whether common polymorphisms in MBL gene are associated with susceptibility to systemic lupus erythematosus (SLE) and its clinical manifestations in a cohort from eastern India. A total of 108 female SLE patients and 105 age, sex, and ethnically matched healthy controls were enrolled in the study. MBL2 codon and promoter polymorphisms were genotyped by AS-PCR and dARMS PCR, respectively. Plasma level of MBL was quantified by ELISA. Higher frequency of BB genotype and minor allele (B) was observed in patients of SLE compared to healthy controls (BB genotype: P = 0.0002; OR = 5.75, 95% CI = 2.09-15.76, B allele: P < 0.0001; OR = 2.78, 95% CI = 1.66-4.64). MBL codon 54, H-550L, Y-221X polymorphisms and combined MBL genotypes contributed to plasma MBL levels. Prevalence of MBL low producer genotype (LXA/LYB, LYB/LYB and LXB/LXB) was significantly higher in SLE patients compared to healthy control. (P = 0.005; OR = 3.09, 95% CI = 1.38-6.91). On analysis of clinical manifestations, MBL low producer genotype was significantly associated with autoimmune haemolytic anaemia (P = 0.006; OR = 13.06). Results of the present study indicate MBL2 variants as possible risk factors for development of SLE and clinical manifestation in eastern India.

Association of MIF-173G/C and MBL2 codon 54 gene polymorphisms with rheumatoid arthritis: a meta-analysis

The aim of this study was to evaluate the association between macrophage migration inhibitory factor (MIF) -173G/C (rs755622), mannose-binding lectin (MBL2) exon 1 codon 54 (rs1800450) gene polymorphisms and rheumatoid arthritis (RA) susceptibility in ethnically different populations. A meta-analysis was conducted (allelic contrast, the additive model, the dominant model and the recessive model) on the MIF-173G/C polymorphism across five studies (four European and one Asian studies), and the MBL2 codon 54 polymorphism with five studies (four Asian and one European studies), respectively. Meta-analysis indicated an association between the MIF-173G/C in all study subjects in allelic contrast (OR=1.19, 95%CI: 1.05-1.35, P=0.001), the additive model (OR=1.68, 95CI: 1.13-2.49, P=0.001), the dominant model (OR=1.17, 95CI: 1.01-1.35, P=0.003), the recessive model (OR=1.63, 95CI: 1.10-2.42, P=0.001). While stratified by ethnicity with European populations, an association was found in allelic contrast (OR=1.20, 95CI: 1.04-1.38, P=0.002), the additive model (OR=1.85, 95CI: 1.19-2.88, P=0.001), the dominant model (OR=1.20, 95CI: 1.02-1.41, P=0.003). With respect to MBL2 codon 54 polymorphism and RA, no association was found in all study subjects in all comparisons, but there was an association while stratified by ethnicity with Asian populations in the dominant model (OR=1.50, 95CI: 1.01-2.23, P=0.007). In conclusion, the present study suggests that the MIF-173G/C polymorphism is associated with RA susceptibility, but the MBL2 codon 54 polymorphism is not associated with RA.

Relevance of the lectin pathway of complement in rheumatic diseases

Due to its importance both in the clearance of pathogens that contribute as rheumatic etiological agents and in the disposal of apoptotic bodies and potential autoimmune initiators, deficiencies of the components of the lectin pathway of complement have been found to increase susceptibility and modulate the severity of most rheumatic disorders. This chapter introduces the general aspects of the structure, function, and genetics of lectin pathway components and summarizes current knowledge of the field regarding rheumatic diseases predisposition and modulation.

Functional mannose-binding lectin levels in patients with end-stage renal disease on maintenance hemodialysis

BACKGROUND

Innate immunity is generally impaired in chronic renal failure (CRF). Mannose-binding lectin (MBL) has an important role in first-line host defense against pathogens via the lectin pathway. We recently reported that functional MBL was significantly lower in CRF patients than in healthy subjects. In this study, we aimed to determine whether functional MBL would be improved following hemodialysis (HD) therapy.

METHODS

This study included 22 patients with end-stage renal disease (ESRD) on maintenance HD. Functional MBL was measured every 6 months for 1 year after HD using an enzyme-linked immunosorbent assay.

RESULTS

Median serum functional MBL levels of ESRD patients were significantly higher after 6 and 12 months than at the start of HD therapy (p < 0.05 and p < 0.01, respectively). Furthermore, median functional MBL levels at 12 months were significantly higher than those at 6 months (p < 0.05).

CONCLUSIONS

We found significant increases in serum functional MBL levels in patients on HD. Our results indicated that HD tailored to remove uremic toxins could improve functional MBL levels in these patients.

The first report described as an important study: The association of mannose-binding lectin gene 2 polymorphisms in children with Down syndrome

BACKGROUND:

Mannose-binding lectin gene 2 (MBL2) plays a very important role in the first line of host immune response in Down syndrome (DS). The importance of MBL2 gene polymorphisms in children with DS is unclear, and no research has addressed MBL2 gene polymorphisms in patients with DS. This is the first report describing an important association between MBL2 gene polymorphisms and infections in children with DS.

MATERIALS AND METHODS:

We compared the frequency of single-nucleotide polymorphisms (SNPs) at two codons of the MBL2 gene in a cross sectional cohort of 166 children with DS and 229 controls. Polymorphisms at codons 54 (GGC→GAC) and 57 (GGA→GAA) in exon 1 of the MBL2 gene were typed by polymerase chain reaction (PCR)-restriction fragment length polymorphism (RFLP) technique using the restriction enzymes BshN1 (derivated from Bacillus sphaericus) and MboII (derivated from Moraxella bovis), respectively.

RESULTS:

MBL2 codon 54 GA genotype frequency was found to be lower in patients with DS (22.9%) than those of healthy controls (35.8%), differences were statistically significant (OR = 0.532, 95% CI = 0.339-0.836, P = 0.008). On the other hand, codon 57 polymorphism in the MBL2 gene was detected in none of the DS patients, but only one person in the control group showed codon 57 GA genotype (OR = 1.004, 95% CI = 0.996-1.013, P = 1.000).

CONCLUSION:

Our data provides an evidence for the first time that a homozygote or heterozygote for the variant, MBL2 alleles, is not associated with infections in patients with DS, and do not influence the incidence of infections.

Mannose-binding lectin gene polymorphisms in Brazilian patients with rheumatoid arthritis

OBJECTIVE

Rheumatoid arthritis (RA) is a disease with unknown etiology but it is probably multifactorial. RA susceptibility is related to genetic, hormonal, immunologic, and environmental factors. Mannose-binding lectin (MBL) is an important protein of the human innate immune system, encoded by the MBL2 gene. Polymorphisms in MBL2 were associated with several diseases, and may be an important factor in RA susceptibility. We analyzed 3 MBL2 gene polymorphisms in 322 Brazilian patients with RA and 345 ethnically matched healthy controls.

METHODS

MBL2 gene variants were analyzed through polymerase chain reaction sequencing.

RESULTS

Considering MBL2 B, C, and D alleles separately, a significant difference in both genotypic and allelic frequencies, particularly concerning frequency of the C allele, was observed comparing European-derived and African-derived individuals (European-derived patients 0.022 vs African-derived patients 0.205; European-derived controls 0.029 vs African-derived controls 0.144; both p < 0.001). We also analyzed MBL2 genotype in relation to extraarticular manifestations. Considering MBL2 variants together, we found an increased frequency of the OO genotype among patients with rheumatoid nodules (p = 0.031), although this association lost significance after Bonferroni correction.

CONCLUSION

Our findings suggest an association of MBL2 genotypes with some clinical manifestations of RA, but more studies are needed to clarify the actual role of MBL in RA.

Mannose binding lectin gene (MBL2) functional polymorphisms are associated with systemic lupus erythematosus in southern Brazilians

Susceptibility to systemic lupus erythematosus (SLE) has been associated with immunologic, environmental, and genetic factors. To uncover a possible association between MBL2 gene polymorphisms and SLE, we analyzed functional polymorphisms in the promoter and first exon of the MBL2 gene in 134 Brazilian SLE patients and 101 healthy controls. Genotype and allele frequencies of MBL2 A/O polymorphism were significantly different between patients and controls, and the O allele was associated with an increased risk of SLE. An association between low mannose binding lectin (MBL) producer combined genotypes and increased risk for SLE was also reported. Furthermore, when stratifying SLE patients according to clinical and laboratory data, an association between the A/O genotype and nephritic disorders and between the X/Y genotype and antiphospholipid syndrome was evident. Combined genotypes responsible for low MBL production were more frequently observed in SLE patients with nephritis. Our results indicate MBL2 polymorphisms as possible risk factors for SLE development and disease-related clinical manifestations.

Relationship between oligomer and functional serum mannose-binding lectin in chronic renal failure

INTRODUCTION

Mannose-binding lectin (MBL) plays an important role in first-line host defence against pathogens via the lectin pathway. The binding affinity for ligands is greatly increased by oligomerization, although the basic triplet does not bind solid phase mannan and cannot activate complement. Besides, MBL is a positive acute-phase protein. In this study, we examined the relationship between oligomer and functional serum MBL in chronic renal failure patients who were either uraemic [Pre-haemodialysis (pre-HD) patients], or who were receiving maintenance haemodialysis treatment (HD patients).

MATERIALS AND METHODS

This study included a total of 20 Pre-HD patients, 130 HD patients and 28 healthy subjects. The oligomer and functional serum MBL levels were measured using enzyme-linked immunosorbent assays established previously.

RESULTS

The median serum functional MBL levels were significantly reduced in both Pre-HD and HD patients compared with healthy subjects (P<0·05 for both). Furthermore, the median functional MBL level in Pre-HD patients was significantly lower than that in HD patients (P<0·05). The median serum oligomer MBL levels in both Pre-HD and HD patients were significantly higher compared with healthy subjects (P<0·05 for both). Furthermore, the median oligomer MBL level in HD patients was significantly (P<0·05) higher than that in Pre-HD patients. The ratios of median serum functional MBL levels to oligomer MBL levels were significantly reduced in both Pre-HD and HD patients compared with healthy subjects (P<0·05 for both).

CONCLUSIONS

We found significant reductions in the ratios of serum functional MBL levels to oligomer MBL levels in HD and Pre-HD patients compared with healthy subjects.

Systemic lupus erythematosus and ethnicity: nature versus nurture or nature and nurture?

Ethnic variation in the frequency and outcome of systemic lupus erythematosus (SLE) has been recognized for decades. The reasons underlying these discrepancies are not completely understood but it is most likely that both genetic and nongenetic factors are responsible for them. Sorting out the extent to which these factors, particularly those of a nongenetic nature, exert their influence in SLE is not easy given inherent methodological difficulties in studying them. To establish this review properly, we would like to make it clear from the outset that ethnicity is a broad construct that implies not only biological but also nonbiological features including cultural and sociodemographic, among others. We will then describe the epidemiological differences of SLE among Caucasian and non-Caucasian populations followed by a succinct review of the genetic predisposition to SLE with special emphasis in ethnic heterogeneity. Differences in disease activity, lupus nephritis, damage and mortality as a function of ethnic group will then be described. Finally, we will present a comprehensive model of the influence of ethnicity on SLE.

Mannose-binding lectin gene (MBL-2) polymorphism in oral lichen planus

TNF-α may be associated with the etiopathogenesis of oral lichen planus (OLP), and it has been suggested that polymorphism of mannose-binding lectin (MBL) increases the in vitro production of TNF- α. The aim of the present study was to assess the relevance of genetic diversity of MBL in OLP. The study sample comprised 90 individuals, 45 OLP patients and 45 healthy volunteers. MBL-2 gene was amplified using real-time PCR. Frequency of A/A genotype was 55.6% in OLP and 53.3% in healthy volunteers. Likewise, A/0 heterozygote genotype was found in 42.2% and 35.6%; 2.2% and 11.1%, had the recessive 0/0 genotype respectively. Frequencies of the "A" and "0" alleles were 77% and 23% in the OLP group and 71.2% in control group. There were no statistically significant differences regarding genotype frequency (p = 0.546) or allele frequency (p = 0.497). In conclusion, no significant association was found between polymorphism of MBL-2 gene and OLP.

Lack of association of mannose-binding lectin gene polymorphisms with development and clinical manifestations of systemic lupus erythematosus in Chinese children

Mannose-binding lectin (MBL) gene polymorphisms may be associated with adult-onset systemic lupus erythematosus (SLE), but studies in children with SLE are rare. This study tested the genetic association between MBL polymorphisms and paediatric-onset SLE in a cohort of Chinese children in Taiwan. In all 150 children with SLE and 100 healthy controls of comparable age were genotyped for codon 52, 54 and 57 mutations of the MBL gene using a polymerase chain reaction–based assay. Clinical manifestations, organ involvement, disease activity, laboratory characteristics and outcome were recorded and compared between patients with different MBL genotypes. Codon 54 mutation was fairly common in both SLE patients and controls, whereas codon 52 and codon 57 mutations were not detected in our study subjects. No statistically significant differences were found in allele frequencies of the codon 54 mutation between SLE and control groups. Moreover, no association was found between this MBL polymorphism and clinical manifestations, organ involvement, disease activity, laboratory characteristics or outcome of SLE. These results suggest that MBL polymorphisms do not influence susceptibility to paediatric-onset SLE and do not influence clinical manifestations of SLE in Chinese children.

Lessons learned from murine models of mannose-binding lectin deficiency

MBL (mannose-binding lectin) is a pattern recognition molecule and a component of innate immunity, the first line of the host defence system against foreign bodies and pathogens. MBL deficiency is common in humans and has been associated with immunodeficiency. We have generated mouse models of MBL deficiency in order to explore the molecular mechanisms of MBL function in disease and health. In addition to confirming findings from human clinical research, these model studies have uncovered unexpected roles of MBL and evidence of its interaction with other molecules of the innate immune system.

Genes and Sjögren's syndrome

The evidence for a strong genetic component conferring susceptibility to primary Sjögren's syndrome (SS) is mounting. Several associations with SS have been reported and provide evidence that the HLA region harbors important susceptibility loci and that multiple genes outside the HLA region play a role. Genetic discovery lags behind success observed in related autoimmune diseases. Identifying genetic factors that cause SS will allow more precise definition of pathogenic mechanisms leading to the overall SS phenotype and clinically heterogeneous subsets of patients. Critical opportunities are certain to follow for translation into improved diagnosis and therapies for SS and its spectrum diseases.

Humoral pattern recognition molecules: mannan-binding lectin and ficolins

Innate immunity comprises a sophisticated network of molecules, which recognize pathogens, and effector molecules, working together to establish a quick and efficient immune response to infectious agents. Complement activation triggered by mannan binding lectin (MBL) or ficolins represents a beautiful example of this network Both MBL and ficolins recognize specific chemical structures on the surface of antigens and pathogens, thus bind to a broad variety of pathogens. Once bound further complement deposition is achieved through a cascade of proteolytic reactions. MBL and ficolin induced complement activation is critical for adequate anti-bacterial, anti-fungal and anti-viral responses. This is well illustrated by numerous and convincing studies that demonstrate associations between MBL deficiency and infections. Recent work has also highlighted that MBL and ficolins recognize self-structures, thus extending the role of these molecules beyond the traditional view of first line defense molecules. It appears that MBL deficiency may modulate the prognosis of inflammatory and autoimmune diseases. What is known about the mechanisms behind this broad scope of activities of MBL and ficolins is discussed in this chapter.

Mannan-binding lectin (MBL) polymorphism and gastric cancer risk in Japanese population

BACKGROUND

Mannan-binding lectin (MBL) is believed to be an important constituent of the innate immune system. It has been reported that the codon 54 G/A polymorphism of exon-1 affects the MBL2 gene and alters its activity.

AIMS

We investigated the association between polymorphism of the MBL2 gene and gastric cancer risk as well as Helicobacter pylori infection in a Japanese population.

METHODS

The study cohort comprised 388 gastric cancer patients and 144 healthy volunteers. Polymorphism at codon 54 of exon 1 of the MBL2 gene was investigated by PCR-based restriction fragment length polymorphism analysis.

RESULTS

There was no significant difference in the distribution of the MBL2 genotype among the gastric cancer patients and healthy controls. However, the carrier of the A allele was more prevalent among patients with a more advanced stage gastric cancer [odds ratio (OR) 1.68, 95% confidence interval (CI) 1.05-2.67; P = 0.03] and also had an increased risk of gastric cancer among patients 65 years of age or younger (OR = 1.6, 95%CI = 1.01-2.52, <0.05).

CONCLUSION

The codon 54 polymorphism of the MBL2 gene is associated with more advanced phenotypes of gastric cancer and the risk of gastric cancer in Japanese patients 65 years of age or younger.

Mannose-binding lectin gene polymorphisms and the development of coal workers' pneumoconiosis in Japan

BACKGROUND

Infection, immunity and genetic factors play roles in the development of coal worker's pneumoconiosis (CWP) and progressive massive fibrosis (PMF). We investigate whether the genetic polymorphisms of mannose-binding lectin (MBL), one of the key molecules of innate immunity, is associated with the susceptibility to CWP.

METHOD

MBL2 polymorphisms (codon54, promoter -221, and -550) were assessed for 197 patients with CWP (119 with nodular CWP and 78 with PMF) and 153 unexposed regional controls. Serum MBL concentrations were measured in 119 CWP patients.

RESULTS

Three polymorphisms were in linkage disequilibrium for all study populations. The MBL2 genotype and haplotypes were associated with lower serum MBL levels. The frequency of such MBL2 genotype and haplotypes were significantly higher in patients with CWP compared to controls, whereas these distributions were not different between patients with nodular CWP and those with PMF.

CONCLUSION

MBL2 polymorphisms and haplotypes may be one of the genetic determinants for the susceptibility of CWP.

Horizons in Sjögren's syndrome genetics

Sjögren's syndrome (SS) is a complex polygenic autoimmune disorder. A few major genetic effects have been identified. Historically, HLA and non-HLA genetic associations have been reported. Recently, the HLA region continued to reveal association findings. A new susceptibility region has been suggested by a study of a D6S349 microsatellite marker. Among non-HLA studies, recent association of immunoglobulin kappa chain allotype KM1 with anti-La autoantibodies in primary Sjögren's syndrome confirms findings in a study from two decades ago. Meanwhile, mouse models have been employed to study the genetic contribution to salivary lymphadenitis or dry eyes and mouth. Gene transfer exploration in mouse models shows promise. The authors review the HLA and non-HLA association studies and the mouse model work that has been reported. Newly developed genomic capacity will provide, in the future, a much closer approximation of the true picture of the genetic architecture of Sjögren's syndrome.

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.

Mannose binding lectin gene polymorphisms and asthma

BACKGROUND

Bronchial asthma is a chronic inflammatory disorder of the airways. Recently, it has been suggested that complement plays significant roles in asthma. Mannose-binding lectin (MBL) is one of the key molecules in complement activation pathways that are associated with several infectious and immune disorders.

SUBJECTS AND METHOD

To investigate whether MBL plays roles in asthma, we analysed MBL2 polymorphisms (allele B, H/L and Y/X) and plasma MBL levels in a Japanese adult population including 232 healthy controls and 579 asthmatics.

RESULTS

Although there was linkage disequilibrium among the three polymorphisms, each polymorphism significantly affects serum MBL levels independently. However, there were no significant differences between asthmatics and controls in MBL2 genotype distribution and in MBL concentrations [1.47+/-0.07(SE) mg/L for asthmatics and 1.66+/-0.14 mg/L for controls, P=0.2]. MBL levels and genotype have no significant relationship with serum IgE, pulmonary functions, and the severity of asthma.

CONCLUSION

Although plasma MBL levels depend on the MBL2 polymorphisms, these polymorphisms and plasma MBL levels are not associated with the asthma phenotype.

Serum mannan-binding lectin levels in patients with celiac disease: an analysis of clinical and autoimmune features

Mannan-binding lectin (MBL) is the central protein in the activation of complement through the lectin pathway. MBL plasma concentration is genetically determined and varies significantly among individuals. Recent findings suggest that MBL is associated with the pathogenesis of celiac disease (CD). In this study, MBL and C-reactive protein (CRP) levels were determined in 101 celiac patients and 120 controls, with the aim to associate with the presence of gluten in the diet, disease severity, and the presence of concomitant autoimmune diseases. MBL concentration was determined by ELISA and CRP by nephelometry, using a high-sensitivity method. EmA-IgA and other autoantibodies were tested by indirect immunofluorescence. Although a significant increase in MBL levels was observed in male patients compared to female (P = 0.024), the absence of any other association suggests that circulating MBL and CRP concentrations are not associated with clinical and autoimmune CD features in Brazilian patients.

The role of the mannose-binding lectin in innate immunity

The innate immune system, which includes mannose-binding lectin (MBL), recognizes a broad range of molecular patterns on a broad range of infectious agents and is able to distinguish them from self. MBL is a liver-derived serum protein and is secreted into the serum, where it can activate an immune response before the induction of antigen-specific immunity. Circumstantial evidence in human populations suggests that low serum levels of MBL predispose to infection. To analyze the role of MBL in vivo, we created MBL-null mice and challenged these mice with infection under various conditions. Our results suggest that MBL plays an important role as a first-line host defense against certain infectious agents. In addition, it is likely that MBL is a key regulator of inflammation beyond expected roles in the infection.

Carbohydrate recognition systems in autoimmunity

The immune system is a complex functional network of diverse cells and soluble molecules orchestrating innate and adaptive immunity. Biological information, to run these intricate interactions, is not only stored in protein sequences but also in the structure of the glycan part of the glycoconjugates. The spatially accessible carbohydrate structures that contribute to the cell's glycome are decoded by versatile recognition systems in order to maintain the immune homeostasis of an organism. Microbial carbohydrate structures are recognized by pathogen associated molecular pattern (PAMP) receptors of innate immunity including C-type lectins such as MBL, the tandem-repeat-type macrophage mannose receptor, DC-SIGN or dectin-1 of dendritic cells, certain TLRS or the TCR of NKT cells. Natural autoantibodies, a long known effector branch of this network-based operation, are effective to home in on non-self and self-glycosylation also. The recirculating pool of mammalian immune cells is recruited to inflammatory sites by a reaction pathway involving the self-carbohydrate-binding selectins as initial recognition step. Galectins, further key sensors reading the high-density sugar code, exert regulatory functions on activated T cells, among other activities. Autoimmune diseases are being associated with defined changes of glycosylation. This correlation deserves to be thoroughly studied on the levels of structural mimicry and dysregulation as well as effector molecules to devise innovative anti-inflammatory strategies. This review briefly summarizes data on sensor systems for carbohydrate epitopes and implications for autoimmunity.

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.

Genetic association study between mbl2 and asthma phenotypes in Chinese children

Mannose-binding lectin (MBL), a member of the innate immune system, initiates complement deposition on microbial surfaces. MBL deficiency is associated with severe respiratory infections. Polymorphisms in the MBL gene (mbl2) were associated with the susceptibility and severity of autoimmune diseases. This study investigated whether mbl2 polymorphisms at positions -550 and -221 and at codon-54 are associated with asthma phenotypes in Chinese children. Asthmatics aged 5-18 yr and non-allergic controls were eligible, and their plasma total and allergen-specific immunoglobulin E (IgE) concentrations were measured by micro-particle immunoassay and fluorescent enzyme immunoassay. mbl2 polymorphisms were genotyped by restriction fragment length polymorphism. Three hundred and seventeen asthmatic children and 140 controls were recruited, with their mean (s.d.) log-transformed plasma total IgE being 2.61 (0.61) and 1.77 (0.77), respectively (p < 0.0001). Polymorphisms at -550 and codon-54 (p < 0.0001 for both) but not at -221 (p = 0.534) of mbl2 were significantly associated with plasma MBL concentrations. mbl2 genotypes were not associated with asthma, atopy, sensitization to individual aeroallergens or spirometric variable. Subjects with LYB haplotype had the lowest plasma MBL concentrations (p < 0.0001), but two- and three-loci mbl2 haplotypes were also not associated with asthma diagnosis. However, patients with LY and LYB haplotypes were less likely to be atopic (p = 0.006 and 0.031). Subjects with LY and LYA were also less likely to be sensitized to cockroach (p = 0.035 and 0.047). The latter three associations became insignificant when adjusted for multiple comparisons. Despite the importance of MBL in innate immunity, our mbl2 polymorphisms only show weak association with asthma and atopy in children.

Unraveling the genetics of systemic lupus erythematosus

The capacity to locate polymorphisms on a virtually complete map of the human genome coupled with the ability to accurately evaluate large numbers (by historical standards) of genetic markers has led to gene identification in complex diseases, such as systemic lupus erythematosus (SLE or lupus). While this is a phenotype with enormous clinical variation, the twin studies and the observed familial aggregation, along with the genetic effects now known, suggest a strong genetic component. Unlike type 1 diabetes, lupus genetics is not dominated by the powerful effect of a single locus. Instead, there are at least six known genetic association effects in lupus of smaller magnitude (odds ratio <2), and at least 17 robust linkages (established and arguably confirmed independently) defining potentially responsible genes that largely remain to be discovered. The more convincing genetic associations include the human leukocyte antigen region (with multiple genes), C1q, PTPN22, PDCD1, Fc receptor-like 3, FcgammaRIIA, FcgammaRIIIA, interferon regulatory factor 5, and others. How they contribute to disease risk remains yet to be clarified, beyond the obvious speculation derived from what has previously been learned about these genes. Certainly, they are expected to contribute to lupus risk independently and in combination with each other, with genes not yet identified, and with the environment. A substantial number of genes (>10) are expected to be identified to contribute to lupus or in its many subsets defined by clinical and laboratory features.

Anti-MBL autoantibodies in patients with rheumatoid arthritis: prevalence and clinical significance

Occurrence of autoantibodies in patients' sera is the characteristic feature of autoimmune disorders. We assessed the presence of anti-mannose binding lectin (MBL) autoantibodies in the sera of 107 rheumatoid arthritis (RA) patients and 121 control subjects by enzyme immunoassay. Elevated levels of anti-MBL autoantibodies in the sera of RA patients (P<0.0001) was detected for the first time. The ratios of anti-MBL positive in RA patients and controls were respectively 60.7% and 1.65%. Experiments were then designed to understand the functional relevance of these autoantibodies. An inverse correlation of anti-MBL autoantibodies with serum MBL levels (P=0.001) and MBL complex activity (P=0.02) was observed without genetic association between MBL polymorphisms and anti-MBL autoantibody secretion. A significant increase (P=0.038) in the level of anti-MBL autoantibodies was observed in 23 synovial fluid samples in comparison to the serum samples. Moreover, the anti-MBL autoantibodies were found to be more often present in the sera of RA patients (60.75% sensitivity, 98.35% specificity and 0.913 area under the ROC curve) in comparison to the IgM and IgG isotypes of rheumatoid factors (RF). Anti-MBL autoantibodies were still positive in 25.23% RA patients when both the RF isotypes were negative. Also, in RA patients, at all stages of disease activity and joint deformity, anti-MBL autoantibodies were more often present than both the RF isotypes. Therefore, the significant presence of anti-MBL autoantibodies enunciates that anti-MBL autoantibodies might have a diagnostic value; however, more studies are needed to confirm the role of anti-MBL autoantibodies in the diagnosis of rheumatoid arthritis.

Innate immunity and the lung: defense at the interface between host and environment

The lung serves as a major interface between the host and the external environment. As such, numerous lines of defense protect the host from inhaled potential pathogens. A breach in pulmonary innate immunity can lead to deleterious outcomes, such as pneumonia and disseminated infection. Pulmonary innate immunity, the first line of defense, is mediated by airway and alveolar epithelial cells as well as resident and recruited leukocytes. This article will discuss the key cellular and secreted components of the pulmonary innate immune system.

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.