Increased frequency of the mannose-binding lectin LX haplotype in Chinese systemic lupus erythematosus patients.

Mannose-binding lectin (MBL) is an important complement-activating protein of the human immune system. As a result of one of three structural gene mutations in exon 1 (variants B, C and D) and/or the presence of a low-efficiency promoter polymorphism, MBL deficiency may be associated with increased susceptibility to infectious diseases and to autoimmune disorders, including systemic lupus erythematosus (SLE). Using a combined approach of heteroduplex generator and polymerase chain reaction, a systematic search for mutations in exon 1 and the promoter region of the MBL gene was performed in a Chinese study population comprising 41 SLE patients and 111 healthy controls. Two alleles, a wild-type allele A and a variant allele B (a previously reported mutation of GGC to GAC at codon 54), were identified in MBL exon 1. The frequency of the B allele (0.15) was higher in the SLE patients than in the healthy controls (0.09), but the difference did not attain statistical significance (P > 0.05). However, for two polymorphisms at positions -550 and -221 in the promoter region, the frequency of the low-MBL-producing haplotype (LX) in the patients (0.2073) was significantly higher than that in the controls (0.0855) (P = 0.003, relative risk = 2.79). Our results suggest that the LX haplotype represents a strong risk factor among Chinese SLE patients. Although of lesser importance, the MBL B allele also may be a risk component in the developing process of SLE in Chinese patients.     

Detection of structural gene mutations and promoter polymorphisms in the mannan-binding lectin (MBL) gene by polymerase chain reaction with sequence-specific primers

This study describes a new approach to the determination of all known mannan-binding lectin (MBL) mutations. The distribution of known variants of the MBL gene in a population of healthy unrelated Danes was determined and the genotype was correlated with the plasma MBL concentrations. The following genetic polymorphisms were studied: three point mutations in the promoter region at position -550 (H/L variants), -221 (X/Y variants), -70 (nt C or T), one point mutation in the 5' untranslated (UT) region at position +4 (P/Q variants) and three point mutations located at codons 52, 54 and 57 in exon 1 of the MBL gene, at nucleotide positions 223, 230 and 239, respectively. To perform genotyping, we designed sequence specific primers for a polymerase chain reaction (PCR-SSP). PCR-SSP is a powerful technique for the discrimination of alleles resulting from single base substitutions and is a widely used technique. Another major advantage of the PCR-SSP method is its ability to determine whether sequence motifs are in cis or trans. The frequencies of variants in exon 1 obtained by PCR-SSP were completely comparable to results obtained by previously described PCR methods, restriction fragment length polymorphism (RFLP) and site-directed mutagenesis (SDM). This PCR-SSP method is performed with standard laboratory equipment and has the capacity to detect all genetic variants in 100 samples in 2 days at an estimated total cost of GBP 11 per sample. Analysing the correlation between MBL haplotype and plasma MBL levels, we confirmed that three different structural variants, B, C and D and the promoter haplotypes HY, LY and LX have a dominant effect on the concentration of MBL. The HY haplotype is associated with the highest plasma concentration, the LY haplotype with intermediate levels and the LX haplotype with the lowest levels. The LX haplotype was found to be associated with very low levels of MBL similar to those found in association with the structural B genotype. The gene frequencies of variants in the MBL gene in the Danish population studied correspond to previous reports on Caucasian populations.     

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.     

Association Between TNF‐α Promoter −308 A/G Polymorphism and Systemic Lupus Erythematosus Susceptibility: A Case–Control Study and Meta‐Analysis

The tumour necrosis factor‐α (TNF‐α) promoter −308 A/G polymorphism plays an important role in the aetiology of systemic lupus erythematosus (SLE). Several studies have estimated the association between TNF‐α −308 A/G and SLE risk. However, results were inconsistent. A case–control study was carried out to explore the association between TNF‐α −308 A/G and the SLE risk in a Chinese Han population. Meta‐analysis combining present with previous studies was conducted to further explore the association. Our case–control study included 556 patients with SLE along with 570 matched healthy controls. TNF‐α −308 A allele was significantly increased in patients with SLE compared with controls (OR = 2.184, 95% CI: 1.718–2.778, P < 0.001). Genotypes AA and AG were associated with the susceptibility to SLE as compared with the GG genotype, as well as the dominant model (AA+AG versus GG), respectively. The meta‐analysis included 41 comparative studies involving 4799 patients and 6635 controls. An association between SLE and allele A was found in the overall populations (OR = 1.70, 95% CI: 1.46–1.98, P < 0.001). In addition, we discussed the correlation between this polymorphism and lupus nephritis (LN) risk, showing that allele A was significantly related to LN in the overall populations (OR = 1.80, 95% CI: 1.21–2.68, P = 0.004). The results from our case–control study and the meta‐analysis indicate that the TNF‐α −308 A allele is significantly associated with an increased risk of SLE/LN.     

The interleukin 6 receptor alpha gene polymorphisms are associated with clinical manifestations of systemic lupus erythematosus in Koreans

The human interleukin 6 receptor consists of two membrane‐bound glycoproteins (IL‐6Rα, IL‐6RA and gp130/IL‐6Rβ, IL‐6RB) interacting with IL‐6, which is a multifunctional cytokine essential to the regulation of the immune response and acute‐phase reactions. We have genotyped a single‐nucleotide polymorphism (SNP) of the IL‐6RA in Korean patients with systemic lupus erythematosus (SLE) (n = 300) and normal controls (NC, n = 299). Three SNPs were identified in the IL‐6RA gene; ‐208 G≥A (NM_000565.3:c.‐208G≥A, rs4845617) in the promoter region, 48841 T≥A (NM_000565.3:c.1067‐17T≥A, rs4845374) in the intron 8 region and 48864 A≥C (NM_000565.3:c.1073A≥C, rs2228145) in the exon 9 region. There were no differences between the SLE and the NC in the genotype and haplotype frequencies. The 48864 A>C polymorphism was significantly associated with rash (P = 0.008). Also, the frequency of rash (P = 0.037), leucopenia (P = 0.033) and lymphopenia (P = 0.027) was significantly higher in patients with SLE having the haplotype HT2 [ATC]. These data suggest that genetic polymorphisms of IL‐6RA gene may be associated with disease phenotypes of SLE in Korean.     

Interleukin 10 gene promoter polymorphisms (rs1800896, rs1800871 and rs1800872) and haplotypes are associated with the activity of systemic lupus erythematosus and IL10 levels in an Iranian population

Systemic lupus erythematosus (SLE) is a chronic autoimmune disease with unknown aetiology. According to the role of interleukin 10 (IL10) in SLE pathogenesis, the genetic alterations in its promoter region could be associated with elevated IL10 levels and exacerbated disease. Here, we investigated the association of genotype and haplotype frequencies of three IL10 gene promoter polymorphisms with susceptibility to SLE, IL10 plasma levels and disease activity of patients in an Iranian population. A total of 116 SLE patients and 131 healthy subjects were enrolled. The PCR‐RFLP technique was used to detect IL10 promoter genotypes at the positions of ?1082 (G/A), ?819 (C/T) and ?592 (C/A) in association with IL10 plasma levels and SLEDAI scores. The GG genotype of ?1082 polymorphism was associated with the increased risk of SLE [OR = 2.65, 95% CI (1.21–5.82), p‐value = 0.046]. The CC genotype in ?819 region was associated with SLE susceptibility [OR = 3.38, 95% CI (1.26–9.07), p‐value = 0.034] and C allele was introduced as risk allele [OR = 1.86, 95% CI (1.15–3.01), p‐value = 0.009] in this region. IL10 plasma levels were overexpressed in CC genotype carriers of ?592 SNP and decreased in AA genotype carriers of ?1082. IL10 was also increased in SLE patients with CGT (?592/?1082/?819) haplotype. The SLEDAI score was higher among CC genotype carriers at the position of ?592 and TT genotype carriers at the region of ?819. SLEDAI was also elevated among patients with CGC (?592/?1082/?819) and CAC (p = 0.011) haplotypes. The present study suggests that the IL10 –819(C/T), ?1082(G/A) and ?592(C/A) polymorphisms and the haplotypes are associated with SLE susceptibility, increased disease activity and elevated IL10 levels. While this is the first time to report such an association in an Iranian population, further studies are needed to confirm these findings.     

Restricted polymorphism of the mannose-binding lectin gene of indigenous Australians

Mannose-binding lectin (MBL) is an important complement-activating protein of the human innate immune system. Deficiency of MBL is associated with an increased risk of various infections and arises from three structural gene mutations in exon 1 (variants B, C and D) and/or the presence of a low efficiency promoter. The C allele is found in sub-Saharan Africa whereas the B allele is found elsewhere, suggesting that these mutations occurred after the suggested hominid migration out of Africa [100-150 000 years before present (BP)]. Paradoxically, these alleles may have a selective advantage in protection against intracellular pathogens and occur at particularly high frequencies in sub-Saharan Africa (C variant) and South America (B variant). Since hominids reached Australia at least 50 000 years ago, a study of MBL polymorphisms in the indigenous population was of interest. Using heteroduplex technology we found a paucity of MBL structural gene mutations in two population groups from geographically distinct regions. Of 293 individuals tested, 289 were wild-type and four were heterozygous for either the B or D allele. In each individual with an MBL mutation the HLA haplotype profile suggested some Caucasian admixture. We also found a restricted range of MBL promoter haplotypes and the serum MBL levels were higher than those of any other ethnic group studied to date (median 3.07 microg/ml). Our data suggest that the B mutation probably arose between 50 000 and 20 000 BP. Its absence from the founder gene pool of indigenous Australians may also partly explain their vulnerability to intracellular infections such as tuberculosis.     

MBL2 Genetic Variants in HCV Infection Susceptibility,Spontaneous Viral Clearance and Pegylated Interferon Plus Ribavirin Treatment Response

Hepatitis C is disease that damages the liver, and it is caused by the hepatitis C virus (HCV). The pathology became chronic in about 80% of the cases due to virus persistence in the host organism. The standard of care consists of pegylated interferon plus ribavirin; however, the treatment response is very variable and different host/viral factors may concur in the disease outcome. The mannose‐binding protein C (MBL) is a component of the innate immune system, able to recognize HCV and consecutively activating the immune response. MBL is encoded by MBL2 gene, and polymorphisms, two in the promoter region (H/L and X/Y) and three in exon 1 (at codon 52, 54 and 57), have been described as functionally influencing protein expression. In this work, 203 Italian HCV patients and 61 healthy controls were enrolled and genotyped for the five MBL2 polymorphisms mentioned above to investigate their role in HCV infection susceptibility, spontaneous viral clearance and treatment response. MBL2 polymorphisms were not associated with HCV infection susceptibility and with spontaneous viral clearance, while MBL2 O allele, O/O genotype, HYO haplotype and DP combined genotype (all correlated with low or deficient MBL expression) were associated with sustained virological response. Moreover, a meta‐analysis to assess the role of MBL2 polymorphisms in HCV infection susceptibility was also performed: YA haplotype could be associated with protection towards HCV infection.     

Mannose-binding lectin polymorphisms in common variable immunodeficiency

Common variable immunodeficiency (CVID) is a heterogeneous group of disorders, characterized by hypogammaglobulinemia and increased susceptibility to infections, autoimmunity and malignancies. This study was performed to analyze the Mannose-binding lectin (MBL) polymorphisms in Iranian patients with CVID. Thirty-five CVID patients who were treated at Children’s Medical Center and 100 matched controls were enrolled in this study. Sixth single-nucleotide polymorphisms of the MBL gene were analyzed using PCR–SSP method. Comparison of MBL exon 1 coding alleles between patients and controls revealed that A allele (wild-type) was significantly decreased in CVID group, whereas B allele was overrepresented in the patient group. High frequency of heterozygous (A/O) in the patient group and high frequency of homozygous for wild-type coding regions in the control group were detected. Comparison of MBL haplotype promoters between CVID patients and controls showed that LYPB haplotype was significantly overrepresented in the CVID group. Mutant and low-producing MBL alleles and haplotypes might reflect as an associated genetic factor in CVID patients, which could play as a susceptibility factor in CVID.     

CTLA‐4 gene polymorphism of exon 1(+49 A/G) in Turkish systemic lupus erythematosus patients

Cytotoxic T lymphocyte‐associated antigen‐4 is a cell‐surface molecule providing a negative signal for T cell activation. CTLA‐4 gene polymorphisms are known to be related with genetic susceptibility to various autoimmune diseases, including systemic lupus erythematosus (SLE). However, the effects of this polymorphism on clinical features of SLE have not been defined. We analysed the CTLA‐4 gene +49 A/G polymorphisms in patients with SLE by using polymerase chain reaction–restriction fragment length polymorphism (PCR–RFLP) and investigated the effect of polymorphisms on clinical outcomes. Blood was collected from 47 unrelated Turkish SLE patients, all fulfilling the American College of Rheumatology criteria for SLE, and 100 ethnically matched healthy volunteers. The AA genotype was a predominant genotype in the Turkish population and genotype frequencies of CTLA‐4 AA were significantly higher in SLE patients (70%) than healthy controls (47%) (P = 0.015). There was a statistically significant difference in the AA genotype [odds ratio (OR): 2.66, confidence interval (CI) 95%: 1.27–5.56, P = 0.014] distribution among patients and controls. There was also an increase in A allele frequency in SLE and controls, but the difference was not statistically significant (81% vs. 70%, P = 0.068, OR = 1.8, CI 95%: 0.99–3.28). Interestingly, mean age and mean age of onset disease was higher in AA homozygote SLE patients compared to non‐AA (39.2 ± 11.5 vs. 31.6 ± 10.6, P = 0.044; 32.38 vs. 24.31, P = 0.046, respectively). There was no association between genotype and the other clinical features of SLE. Our results suggested that CTLA‐4 +49 AA genotype might be a risk factor for the development of SLE in Turkish population and G allele might be involved in early development of SLE. No association with clinical features was found for polymorphism of the promoter region in CTLA‐4 +49.     

A promoter polymorphism (rs3806798) of interleukin‐15 gene is associated with chronic hepatitis B virus infection in the Chinese Han population

This study aimed to investigate the association between the polymorphisms of IL‐15 gene and susceptibility to chronic hepatitis B virus (HBV) infection in the Chinese Han population. A total of 234 patients with chronic HBV infection and 150 age‐ and sex‐matched healthy controls in the Chinese population were enrolled in this case–control study. Genotyping of ten single nucleotide polymorphisms (SNPs) in the IL‐15 gene was carried out via Sequenom MassARRAY system. The association analysis demonstrated that SNP rs3806798 (A/T) had a significant difference in the distribution between patients and healthy controls (P = 0.033). Moreover, a significantly increased risk of HBV infection was found to be associated with IL‐15 rs3806798 A allele among male patients and HBeAg‐negative patients, compared with IL‐15 rs3806798 T allele (P = 0.003; P = 0.046, respectively). Furthermore, haplotype analysis revealed that haplotype ATAGG (rs3806798, rs12508866, rs1519551, rs6819823 and rs2857261, respectively) in block 1 was significantly associated with HBV infection (P = 0.022). In conclusion, we found an association between IL‐15 rs3806798 and the risk of chronic HBV infection in a sample of Chinese Han population.     

幼年特发性关节炎患儿甘露糖结合凝集素基因启动子区SNP研究

目的探讨甘露糖结合凝集素(MBL)基因启动子区单核苷酸多态性(SNP)与幼年特发性关节炎(JIA)易感性的关系。方法对50例JIA患儿和48名正常健康儿童MBL基因启动子区SNP位点-550(G/C,称H/L等位基因)和-221(G/C,称X/Y等位基因)采用等位基因特异性PCR法(PCR-SSP)检测,并分析其单元型及基因型频率。结果共检出HY、LY和LX三种单元型,在JIA患儿中的频率依次为0.540、0.270和0.190,而在正常儿童中频率分别为0.594、0.292和0.114;两组间各单元型比较均无显著性差异。结论MBL基因启动子区单核苷酸多态性与JIA无相关性。     

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.     

The genetic contribution of HLA‐DRB5*01:01 to systemic lupus erythematosus in Thailand

Human leucocyte antigen (HLA) study in patients with systemic lupus erythematosus (SLE) has been investigated in various countries, but the results are still inconclusive. This study was performed to investigate the association between HLA‐DR and SLE in patients in northern Thailand. HLA‐DR subtyping was performed in 70 patients with SLE and 99 normal healthy controls living in northern Thailand using the INNO‐LiPA HLA‐DR Decoder kit (Innogenetics) and MICRO SSP HLA DNA Typing kit (One Lambda) for reconfirmation. The allele frequency (AF) of DRB5*01:01 in SLE was significantly higher than in the controls [25.7% vs. 14.6%, P = 0.012, Pc = 0.048, OR = 2.02 (95%CI = 1.17–3.48)]. The AF of DRB1*15:01 and DRB1*16:02 showed a nonsignificant tendency to be higher in SLE (10.7% vs. 8.1%, and 17.9% vs. 11.1%). Interestingly, the DRB5*01:01 allele linked to DRB1*16:02 in 47.2% of SLE and 37.9% of controls, and the prevalence of the DRB1*16:02‐DRB5*01:01 haplotype was higher in the patients with SLE [12.1% vs. 5.6%, P = 0.044, OR = 2.35 (95%CI = 1.06–5.19)]. The DRB1*16:02 linked to DRB5*02:02 and *02:03 in 18.2% and 31.8% of controls, respectively, and linked to DRB5*02:03 in 32.0% of SLE patients. The frequency of DRB1*03:01 and *15:02 alleles was not increased in Thai SLE. There was no significant association between DRB5*01:01 and any auto‐antibodies or clinical manifestations of SLE. DRB5*01:01 is associated with Thai SLE, and the association is stronger than that of DRB1*15:01. The genetic contribution of DRB5*01:01 is due partially to the linkage disequilibrium between DRB1*16:02 and DRB5*01:01 in the northern Thai population.     

MBL2 polymorphisms – manifestations in Bulgarian patients with adult dermatomyositis and systemic lupus erythematosus

Deficiency in some complement factors is known to cause both systemic lupus erythematosus (SLE) and dermatomyositis (DM). Mannose‐binding lectin (MBL) is a recognition molecule of the lectin pathway, and its low levels are reported to influence some autoimmune diseases. Furthermore, MBL2 polymorphisms have been described associated with low MBL serum levels due to impaired MBL structure and function. This is a pilot study to investigate the role of MBL2‐550G/C (H/L), ‐221G/C (Y/X), Arg52Cys (D), Gly54Asp (B), Gly57Glu (C) polymorphisms and MBL serum levels as a risk factor for a development of adult DM and SLE in Bulgarian patients. None of the studied MBL2 polymorphisms appeared associated with the diseases investigated. However, we have found an increased OR of MBL2‐221XY genotype in the patients with SLE (OR 1.64, 95%CI 0.77–3.52). MBL2 polymorphisms seemed to affect MBL serum levels and to be associated with the clinical features although none of the associations remained statistically significant after Bonferroni correction. The‐550L allele showed an association with electromyography findings in patients with DM. The‐221XY genotype was associated with photosensitivity in patients with SLE. The 54AB genotype showed an association with malar rash in patients with SLE, but it appeared decreased among SLE patients with ANA. In conclusion, our results suggest that the MBL2 polymorphisms have rather a disease modifying role and they are not associated with the disease susceptibility in adult DM and SLE among Bulgarian patients.     

TNFSF4 polymorphisms are associated with systemic lupus erythematosus in the Malaysian population

Tumour necrosis factor superfamily 4 (TNFSF4) gene has been reported to be associated with systemic lupus erythematosus (SLE) susceptibility due to its encoding for OX40L protein that can increase autoantibody production and cause imbalance of T‐cell proliferation. The purpose of this study was to investigate the association of TNFSF4 rs2205960, rs1234315, rs8446748 and rs704840 with SLE in the Malaysian population. A total of 476 patients with SLE and 509 healthy controls were recruited. Real‐time polymerase chain reaction (PCR) was applied to genotype the selected single nucleotide polymorphisms (SNPs). Allelic and genotypic frequencies of each SNP were calculated for each ethnic group, and association test was performed using logistic regression. The overall association of each SNP in Malaysian patients with SLE was determined with meta‐analysis. The frequency of minor T allele of TNFSF4 rs2205960 was significant in Chinese and Indian patients with SLE, with P values of 0.05 (OR = 1.27, 95% CI: 1.00–1.61) and 0.004 (OR = 3.16, 95% CI: 1.41–7.05), respectively. Significant association of minor G allele of rs704840 with SLE was also observed in Chinese (P = 0.03, OR = 1.26, 95% CI: 1.02–1.56). However, after Bonferroni correction, only T allele of rs2205960 remained significantly associated with Indian cohort. Overall, minor G allele of rs704840 showed significant association with SLE in the Malaysian population with P values of 0.05 (OR = 1.20, 95% CI: 1.00–1.43). We suggested TNFSF4 rs704840 could be the potential SLE risk factors in the Malaysian population.     

Gene-environment interaction between MBL2 genotype and smoking, and the risk of gram-positive bacteraemia

Mannose-binding lectin (MBL) insufficiency caused by point mutations in the MBL2 gene has been associated with increased susceptibility to bacteraemic infections. We here investigated the effect of MBL2 polymorphisms on the susceptibility and clinical course of bacteraemia. The study cohort comprised 145 patients with bacteraemia and 400 controls. In the case of patients with bacteraemia, laboratory findings and clinical data were registered on admission and during six consecutive days. MBL2 structural polymorphisms at codons 52 (CGT→TGT; designated D or O), 54 (GGC→GAC; B or O) and 57 (GGA→GAA; C or O) in exon 1 of the MBL2 gene and promoter region polymorphisms at position −221 (G→C, designated Y or X alleles) were determined. No difference in MBL2 genotype frequencies between the bacteraemic patients and controls was detected, and MBL2 genotype had no independent effect on mortality, nor disease severity. However, smoking proved a significant risk factor for Gram-positive ( Staphylococcus aureus , Streptococcus pneumoniae or β-haemolytic streptococci) bacteraemia in patients carrying the variant O allele (53% current smokers in Gram-positive bacteraemia patients compared with only 21% in controls, odds ratios 4.2, 95% confidence intervals 2.0–9.0; P  < 0.001), while it did not have an effect in those homozygous for the A allele. The same effect was not detected in Escherichia coli bacteraemia. In conclusion, MBL2 genotypes representing MBL insufficiency were not associated with the overall risk of bacteraemia or disease severity, but smoking in carriers of the structural variant O allele may have a deleterious effect increasing the risk of Gram-positive bacteraemia.     

Association of mannose-binding lectin gene (MBL2) polymorphisms with rheumatoid arthritis in an Indian cohort of case-control samples

Single nucleotide polymorphisms in the mannose-binding lectin (MBL2) gene, as well as the serum MBL2 level, have been associated with various autoimmune diseases. We investigated whether such polymorphisms and/or the serum MBL2 level were associated with rheumatoid arthritis (RA) in an Indian population. The frequency of the B variant (codon 54) of the MBL2 gene was quite frequent in the healthy Indian population and was significantly (P=6.35×10^–6) lower in RA patients. We replicated this association (P=1.78×10^–5) in an independent cohort of control individuals. Promoter polymorphism at –550 nt showed a significant overrepresentation (P=0.003) of the minor allele G in severe RA patients compared with the less severe group. Haplotype LYA frequency was significantly (P=0.03) high in the less severe group, while the frequency of the HYA haplotype was significantly (P=0.04) increased in the severe RA patients. No statistically significant difference in serum MBL2 was observed as a whole, but the individuals homozygous for the LYA haplotype had significantly lower (P=0.017) serum MBL2 levels compared with individuals homozygous for the HYA haplotype. Therefore, the B variant of the MBL2 gene may be associated with protection from RA in our study population, and the promoter polymorphism (–550 nt) seems to have some role in disease progression.     

Association of HYPA haplotype in the mannose-binding lectin gene-2 with Behçet's disease

Behcet's disease (BD) is a multisystemic, recurrent inflammatory disease caused by the combinations of multiple genetic and environmental factors. Moreover, the MBL2 gene single-nucleotide polymorphisms and haplotypes are known to increase the susceptibility to inflammatory disease and to alter the serum levels of mannose-binding lectin (MBL. We postulated that the haplotypes of the MBL2 gene influence therapeutic response in BD, thus affecting the clinical symptoms in 282 BD patients. The promoter region, MBL2-550*C/*C (L/L) homozygote was found to have a lower frequency in BD patients than that in controls. No difference was observed in the allele frequencies of G-221C (Y/X), C+4T (P/Q) or Gly54Asp (A/B) of the MBL2 gene in BD patients and in controls. The HYPA haplotype contributed to BD occurrence, whereas the LYPA haplotype was negatively associated with BD. BD patients with several symptoms and with an earlier disease-onset age had a higher HYPA haplotype frequency. BD patients showing poor response (S) to therapy had a higher HYPA frequency than those showing good response (M). It seems that possessing HYPA increases the risk of BD and that the MBL2 HYPA haplotype plays a role in MBL levels and increases the susceptibility to BD.     

Single‐nucleotide polymorphisms of IRF8 gene are associated with systemic lupus erythematosus in Chinese Han population

Interferon regulatory factor 8 (IRF8) has been shown to have diverse roles in the regulation of the immune system. Two recent studies had revealed the association between the single‐nucleotide polymorphisms (SNPs; rs11644034 and rs2280381) of IRF8 and systemic lupus erythematosus (SLE) in a multiethnic population. The purpose of this study was to evaluate whether the association could be replicated in a Chinese Han population. Genotypes were determined by a multiplex polymerase chain reaction–ligase detection reaction (PCR–LDR) in 358 patients and 357 geographically matched healthy controls. Significant differences in genotype frequency were found between SLE and control individuals (rs11644034: AA vs. GG, P = 0.014, odds ratio (OR) = 0.980, 95% confidence internal (CI): 0.964–0.996; rs2280381: CC vs. TT, P = 0.005, OR = 0.150, 95% CI: 0.033–0.676). Conditional logistic regression analysis showed that the association of rs2280381 remained significant (P adjusted = 0.028) after adjustment for rs11644034, but not vice versa (P adjusted = 0.361).When stratifying patients with SLE according to clinical subtypes, SNP rs2280381 was found to be associated with low complement in patients with SLE. However, SNP rs11644034 was not found to be associated with SLE clinical subgroups. Analysis of the haplotypes revealed that haplotype G‐T and G‐C were also significantly associated with SLE (P = 0.002 and P = 0.012, respectively). Our study indicated that the IRF8 gene polymorphisms might be associated with susceptibility to SLE and with disease‐related clinical manifestations in Chinese Han population.