High frequency of the IL-2 −330 T/HLA-DRB1*1501 haplotype in patients with multiple sclerosis

We have evaluated the role of the HLA-DRB1*1501 allele and the IL-2 −330 T/G polymorphism and their interaction in susceptibility to multiple sclerosis on 360 patients and 426 matched healthy individuals. We used the SSP-PCR method to determine the alleles. Fisher's exact test was used to analyses. We observed a significant increase in the T allele at IL-2 −330 position in patients (OR = 1.34, P < 0.05), and the T/T and T/G genotypes were more frequent among patients than controls. The HLA-DRB1*1501 allele was overrepresented in patients as compared to the control group (OR = 1.7, P = 0.0006). The two-locus analysis of the interaction between the IL-2 promoter polymorphism and the HLA-DRB1 allele showed that the HLA-DRB1*1501/T haplotype was more frequent in patients than controls (OR = 16, P < 0.0001). Our findings support previous findings about the role of the HLA-DRB1*1501 allele in susceptibility to MS. This work also provides new findings about the importance of gene–gene interactions in the development of MS.     

The influence of the HLA-DRB1 and HLA-DQB1 allele heterogeneity on disease risk and severity in Iranian patients with multiple sclerosis

Multiple sclerosis (MS) is a common autoimmune disorder of the central nervous system. Recent studies have shown that the HLA‐DRB1 and DQB1 alleles are associated with MS susceptibility and severity. However, this is controversial in different population studies. In the present study, the roles of HLA‐DRB1 and DQB1 alleles and the amino acids were investigated on disease risk and severity in 120 Iranian patients with MS and 120 controls. Our findings indicate that the DRB1*1501 allele (OR = 3.203 P = 0.001), the DRB1*1501‐DQB1*0602 haplotype (OR = 7.792 P = 0.003) and the DRB1*1501/0701‐ genotype (OR = 3.320 P = 0.006) and amino acid Leu26 (OR = 1.645 P = 0.005) and Phe9 (OR = 1.893 P = 0.009) on the DQβ1 chain are significantly associated with MS susceptibility. DRB1*1001 was the only allele that had a protective effect against MS (P = 0.0004). We also found that the DQB1*0303 allele was significantly associated with disease severity (mean Multiple Sclerosis Severity Score difference = 1.979, P = 0.002). However, protective effect of the DRB1*1001 against MS and also association of DQB1*0303 allele with MS severity need to be confirmed by larger sample size.     

The association of −330 interleukin‐2 gene polymorphism and HLA‐DR15 allele in Iranian patients with multiple sclerosis

The purpose of this case–control study was to evaluate the frequencies and potential genetic susceptibility of the ?330 IL2 T and G alleles and HLA‐DRB1*1501 allele in Iranian patients with multiple sclerosis (MS) compared to healthy controls. Two hundred and sixty Iranian patients with MS from medical genetics department of Sarem Women hospital were selected. Besides, 450 ethnically age‐ and sex‐matched healthy individuals without personal or family backgrounds of autoimmune disorders were enrolled as a control group. All polymorphisms were analysed using RFLP‐PCR technique. HLA‐DRB1 genotyping was carried out by HISTO TYPE SSP high‐resolution Kits according to the manufacturer's suggestions. The frequency of the T allele at the ?330 IL2 polymorphism was significantly higher in patients with MS than controls (OR: 2.45, 95 CI: 1.9–3, P = 4 × 10^?14). Moreover, the T/T genotype was more frequent in patients than in controls (51% vs. 30%). This study indicated that the ?330 T IL2 allele and the T/T genotype were related to increased plasma concentration of IL2 and a higher risk of developing MS among Iranian patients. Carrying both the ?330 T IL2 and the HLA, DRB1* 1501 alleles showed the most susceptibly effect to MS. Our data demonstrated ?330 T IL2 allele provided major susceptibility to MS and HLA‐DRB1* 1501 allele had an additive effect. In addition, it seems that studies with larger sample size are required to bring about more authentic results. Our findings suggest that IL2 gene polymorphisms influence the susceptibility to MS in Iranian patients.     

A NOTCH4 association with multiple sclerosis is secondary to HLA-DR*1501

Multiple sclerosis (MS) is a chronic inflammatory disease of the central nervous system (CNS) with supposedly autoimmune features known to be associated with a specific HLA DR-DQ haplotype (DR15, DQ6, or HLDRB1*1501,DRB5*0101,DQA1*0102,DQB1*0602). We have previously reported that the associated haplotype extends to HLA-B and described an independent association with HLA-A alleles in MS. Owing to a complex situation with extensive linkage disequilibria, it is still unclear whether classical HLA genes are responsible or whether associations may be due to other genes in this region. Here, we analyzed an association in MS with the NOTCH4 and TNFalpha (tumor necrosis factor-alpha) genes, located between the HLA-DRB1 gene and the HLA-A gene. For NOTCH4, located 0.4 Mb telomeric to HLA-DRB1, an SNP at position -25 and a trinucleotide repeat were investigated in 181 MS patients, and 180 controls also typed P = 0.027 for HLA-DRB and HLA-A. A modest association was observed (OR = 3.44) with the C-25 allele. However, two-locus analysis revealed that this association was secondary to the classical association with HLA-DRB1. For TNF, located 0.7 Mb telomeric of NOTCH4, SNPs at positions -308 and -238 were studied in the same dataset. We found no association between these TNFalpha gene polymorphisms and MS in this dataset, although there was linkage disequilibrium (LD) between DRB1 and TNF and between HLA-A and TNF. We conclude that alleles of the NOTCH4 and TNFalpha genes are unlikely to be of importance for the susceptibility to MS, although specific alleles of these genes are often carried on the same haplotype as DR15, DQ6.     

Significant association of HLA-B and HLA-DRB1 alleles with cleft lip with or without cleft palate

Nucleotide sequence level typing of HLA-B, -DRB1, and -DPB1 alleles was performed on Japanese patients with cleft lip with or without cleft palate (CL/P). Two HLA-B alleles, B*1501 and B*5101, showed a significant positive association with CL/P. The increase of B*1501 was evident in female patients (OR=3.6, Pc=0.003), whereas the increase of B*5101 was evident in male patients (OR=3.7, Pc < 0.001). One HLA-DRB1 allele, HLA-DRB1*0802 also showed an increase in CL/P patients. Conversely, HLA-B*4403 and DRB1*1302 were not observed in the patient group (Pc=0.01 and Pc=0.02, respectively). No HLA-DPB1 alleles showed significant association with CL/P. Thus, the present study indicates that HLA alleles, or closely linked loci, may be involved in the pathogenesis of CL/P.     

Association of tumour necrosis factor-alpha, lymphotoxin-alpha and HLA-DRB1 gene polymorphisms with Löfgren's syndrome in Czech patients with sarcoidosis

Sarcoidosis is a granulomatous disorder showing a clear association with MHC (HLA) class I and class II genes. In order to investigate whether polymorphisms of nearby pro-inflammatory genes located within the MHC class III region may also contribute to susceptibility to sarcoidosis or to its clinical manifestation, tumour necrosis factor-alpha (TNF-alpha) and lymphotoxin-alpha (LT-alpha) genes were chosen for analysis in a case-control association study. In order to evaluate the findings on the TNF-alpha and LT-alpha genes in connection with the closely linked MHC class II region, 'classical' HLA-DRB1 locus was also investigated. Polymerase chain reaction-based methodologies were used in order to characterize two single-nucleotide polymorphisms (TNF-308*G/A and LTAlpha+252*A/G) and HLA-DRB1 allele groups in 114 Czech patients with pulmonary sarcoidosis and 425 healthy controls. LTA+252*G and HLA-DRB1*13 allele carriers were more frequent in patients, compared to those in controls. By contrast, HLA-DRB1*07 carriers were less frequent among sarcoidosis patients. The overrepresentation of TNF-308*A, LTAlpha+252*G and HLA-DRB1*03 allele carriers was found in a subgroup of sarcoidosis patients presenting with Lofgren's syndrome (LS) by comparison with the subgroup of patients without LS (NLS; phenotype frequency LS vs NLS: 68.8 vs 37.1% for TNF-308*A, 93.8 vs 66.3% for LTA+252*G and 68.8 vs 21.3% for DRB1*03). The data suggest that the LTAlpha and HLA-DRB1 genes themselves or a gene located nearby contributes to the susceptibility to sarcoidosis and that TNF-308*A, LTA+252*G and HLA-DRB1*03 alleles are associated (directly or via linkage with unknown causative locus) with LS as a specific manifestation of the disease.     

A Taqman assay for high-throughput genotyping of the multiple sclerosis-associated HLA-DRB1*1501 allele

The human leukocyte antigen (HLA)-DRB1*1501 allele has long been established as the main genetic risk factor for multiple sclerosis (MS), and it therefore follows that stratification of study populations for this allele could aid in the identification of novel susceptibility genes and/or in establishing interactions. To this end, we have developed a simple Taqman-based assay allowing cost-efficient medium-throughput HLA-DRB1*1501 genotyping. We have validated this assay in 444 trio families with MS and 1066 individuals from the UK 1958 birth cohort (3908 independent chromosomes). In this validation cohort, the correlation coefficient (r(2)) between rs3135388*A and HLA-DRB1*1501 was >0.94. Subsequently, applying the assay to a group of MS patients and controls from Belgium confirmed the association of HLA-DRB1*1501 and MS in this population (P = 5 x 10(-21)).     

Molecular analysis of HLA class I (HLA-A and -B) and HLA class II (HLA-DRB1) genes in Japanese patients with multiple sclerosis (Western type and Asian type)

Abstract: The types of HLA-A, -B and -DRB1 genes were studied in 146 Japanese patients with multiple sclerosis (MS) using polymerase chain reaction-sequence-specific oligonucleotide probe analysis. Fifty-seven patients who displayed selective clinical involvement of the optic nerve and spinal cord were classified as having Asian type MS. The other 89 patients had disseminated central nervous system involvement and were classified as having Western type MS. The frequency of HLA-B*5101 was increased in both types of MS patients compared with controls. The frequency of HLA-DRB1*1501 was increased in Western type MS and the frequency of HLA-DRBl*0802 was increased in Asian type MS compared to controls. After correction of P values, the association of Western type MS patients with HLA-DRB1*1501 was statistically significant ( Pc =0.0003) whereas other HLA alleles showed no significant association. These results suggest that HLA class I (HLA-A and -B) alleles may not contribute to a strong susceptibility to MS in Japanese compared to HLA class II (HLA-DRB1) alleles.     

HLA (A-B-C and -DRB1) alleles and brain MRI changes in multiple sclerosis: a longitudinal study

Several major histocompatibility complex (MHC) alleles have been postulated to influence the susceptibility to multiple sclerosis (MS), as well as its clinical/radiological course. In this longitudinal observation, we further explored the impact of human leukocyte antigen (HLA) class I/II alleles on MS outcomes, and we tested the hypothesis that HLA DRB1*1501 might uncover different strata of MS subjects harboring distinct MHC allele associations with magnetic resonance imaging (MRI) measures. Five hundred eighteen MS patients with two-digit HLA typing and at least one brain MRI were recruited for the study. T2-weighted hyperintense lesion volume (T2LV) and brain parenchymal fraction (BPF) were acquired at each time point. The association between allele count and MRI values was determined using linear regression modeling controlling for age, disease duration and gender. Analyses were also stratified by the presence/absence of HLA DRB1*1501. HLA DRB1*04 was associated with higher T2LV (P=0.006); after stratification, its significance remained only in the presence of HLA DRB1*1501 (P=0.012). The negative effect of HLA DRB1*14 on T2LV was exerted in DRB1*1501-negative group (P=0.012). Longitudinal analysis showed that HLA DRB1*10 was significantly protective on T2LV accrual in the presence of HLA DRB1*1501 (P=0.002). Although the majority of our results did not withstand multiple comparison correction, the differential impact of several HLA alleles in the presence/absence of HLA DRB1*1501 suggests that they may interact in determining the different phenotypic expressions of MS.     

The DRB1 Val86/Val86 genotype associates with multiple sclerosis in Australian patients.

Genetic susceptibility to multiple sclerosis (MS) has so far been strongly localized to the MHC class II region encoding the alleles of the haplotype HLA-DRB1*1501, -DQA1*0102, -DQB1*0602. However, this haplotype is not carried by approximately 40% of MS patients; a potential explanation could be that they carry other MHC class II alleles with similar function due to the sharing of nucleotide sequences encoding critical amino acid residues. The DRB1 gene is polymorphic at residue 86, encoding valine or glycine. In view of the increasing evidence for a functional role for DRB1 aa86 in the binding and presentation of autoantigenic peptides such as myelin basic protein, this study investigated associations with the residue 86 polymorphism in an Australian MS population. A significant increase in the Val86/Val86 genotype was observed in the MS patients, which was still present in the absence of the DRB1*1501 allele (p = 0.032). This suggest that DRB1 aa86 may have an independent role in contributing to MS susceptibility. The Val86/Val86 genotype was correlated with genotyping for other putative MS susceptibility genes, including T cell receptor beta chain germline polymorphisms, HLA-DMB alleles, and -DQA1 and -DQB1 alleles encoding critical amino acid residues, with a significant interaction only observed with DQB1 Leu26 (p = 0.014). Additional studies of the HLA-DRB1 aa86 polymorphism in MS, and its function, are needed to more fully understand this association.     

Analysis of BTNL2 genetic polymorphisms in British and Dutch patients with sarcoidosis

Sarcoidosis is a heterogeneous disorder, both phenotypically and genetically. Two independent studies have recently shown that a functional polymorphism within butyrophilin-like 2 (BTNL2) gene predisposes to sarcoidosis independently of the human leukocyte antigen (HLA)-DRB1 alleles. However, in both studies, data analysis was not stratified by L?fgren's syndrome, a clinically and genetically distinct sarcoidosis subset. BTNL2, potentially encoding an immune coreceptor, is adjacent and in linkage disequilibrium (LD) with HLA-DRB1. We investigated six BTNL2 variants, including the functional rs2076530 (G > A), as well as HLA-DRB1 alleles, by sequence-specific primers-polymerase chain reaction, in 288 patients and 446 controls from two European countries. In the patient group as a whole, the HLA-DRB1*14 [odds ratio (OR) = 3.1, P(c) = 0.0003], DRB1*12 (OR = 2.5, P(c) = 0.003), and BTNL2 rs2076530 A allele (OR = 1.49, P(c) = 0.002) were all associated with disease susceptibility. However, after exclusion of patients presenting with L?fgren's syndrome and after adjusting for HLA-DRB1 alleles, the association between BTNL2 rs2076530 A and disease disappeared (P = 0.23). By contrast, both HLA-DRB1*14 and DRB1*12 remained strongly significant (OR = 3.60, P < 0.0001 and OR = 3.03, P = 0.003, respectively). BTNL2 haplotype 4, tagged by the rs2076530 G allele, also remained associated with non-L?fgren sarcoidosis after adjusting for HLA-DRB1 alleles (OR 0.37, P = 0.016). In summary, HLA-DRB1*14, DRB1*12, and BTNL2 haplotype 4--but not rs2076530 A--are associated with non-L?fgren sarcoidosis. However, the tight LD across the HLA complex makes it difficult to identify the precise location of the susceptibility locus/i. Larger sample sets from different ethnic groups, finer mapping, and more robust LD analyses across the HLA region are needed.     

Both the HLA-CPB1 and -DRB1 alleles correlate with risk for multiple sclerosis in Japanese: clinical phenotypes and gender as important factors

The purpose of this study was to clarify the association of HLA-DRB1 and -DPB1 alleles with multiple sclerosis (MS) in Japanese, to determine whether optico-spinal MS (OS-MS) and conventional MS are immunogenetically distinct, and to verify the role of gender difference in HLA associations of MS. We studied HLA-DRB1 and -DPB1 polymorphisms in 166 Japanese patients with MS. Forty-seven patients were classified as having the optico-spinal MS (OS-MS) and 119 as having conventional MS. A lack of DPB1*0301 and a higher frequency of DPB1*0501 compared with controls (corrected P<0.0074; odds ratio=9.48) were found in OS-MS. By contrast, we found for the first time an association of DPB1*0301 with conventional MS in Japanese (corrected P=0.0444; odds ratio=3.28). Logistic analysis, adjusted for sex and age, revealed independent associations of DPB1*0301 (P=0.0004, adjusted odds ratio (aOR)=4.70), DPB1*0501 (P=0.0081, aOR= 2.50) and DRB1*1501 (P=0.0252, aOR=2.21) with conventional MS. However, the frequencies of DRB1*1501 and DPB1*0501 in male patients with conventional MS were equal to those in male controls while the DPB1*0301 frequency was increased in both male and female patients. We did not find any association of these HLA alleles with disease course and severity. In conclusion, OS-MS is a DPB1*0501-associated distinct subtype of MS, and DPB1*0301 is the most strongly associated allele with conventional MS in Japanese. In addition, gender plays an important role in HLA association with MS.     

Evidence for novel DRB1*15 allele association among clinically definite multiple sclerosis patients from Mumbai,India

Multiple sclerosis (MS) is a clinically heterogeneous demylinating disease and an important cause of acquired neurologic disability. MS has been reported from different regions of India and its infrequency has been attributed to have genetic implications. Further, a high incidence of MS and its human leukocyte antigen B12 (HLA-B12) associations have been reported among highly inbred Parsi population from Mumbai. However, consistent HLA associations have not been reported from India. We analyzed the HLA-B, -Cw, and -DRB1 allele associations among 23 clinically definite Western Indian non-Parsi MS patients and compared them with 146 ethnically matched clinically normal individuals. HLA serologic (A, B, and Cw) as well as molecular (DRB1) typing methodology was followed. The study revealed a significant increase of HLA-A11 (24% vs. 13%; OR = 2.6; EF = 0.14; 95%CI = 1.1-3.05), B16 (4.3% vs 0.3%; OR = 13.8; EF = 0.03; 95% CI = 1.19-134.44), Cw7 (15.2% vs 3.7%; OR = 5.46; EF = 0.12; 95% CI = 0.944-17.86), and DRB1*15 (21.7% vs 2.2%; OR = 16.15; EF = 0.19; 95% CI = 1.33-68.64). Further molecular subtyping of HLA-DRB1*15 among the patients revealed two novel alleles, DRB1*1506 (20%) and DRB1*1508 (30%), along with the commonly reported DRB1*1501 (50%) for the first time in MS patients that were hitherto unidentified from other parts of India and world as well. This study reveals that there is a complexity of the genetic susceptibility to MS in different populations studied and reported.     

HLA and tumour necrosis factor (TNF) polymorphisms in ocular Behçet's disease

The role of HLA-B*51 and other major histocompatibility complex (MHC) genes in Beh?et's disease (BD) remains unknown. We have performed HLA and tumour necrosis factor (TNF) polymorphism analysis in BD and evaluated their contribution to ocular disease. In this study, 102 patients and 115 controls of Middle Eastern descent were investigated by HLA and B*51 subtyping using novel primers, and by LT alpha NCo 1 and TNF 308 promoter polymorphism analysis. The frequency of the HLA-B*51 family of alleles was raised in patients compared to controls (66% vs. 15%, Pc=2.5x10(-12), OR=10.9). The odds ratio (OR) of this group of alleles for subgroups of patients was as follows: non-ocular patients 7.8, all ocular patients 12.6, blind patients >22. HLA-B*51 subtyping detected B*5101, 07, 08 and 09 alleles, with a similar frequency among patients and controls. HLA-Cw*1602 was associated with B*5108, but was not an independent risk factor for disease. The LT alpha (TNFB*2) allele was associated with HLA-B*51 among patients and the frequency of this allele was significantly higher among completely blind patients compared to both non-ocular patients (P=0.048, OR >3.6) and to healthy controls (P=0.022, OR >4.3). The rare TNF-2 polymorphism at the TNF -308 promoter position was associated with HLA-B*50 (not B*51), and was not associated with BD. Thus, in this population the HLA*B51 family of alleles is a strong risk factor for BD, and in particular the development of ocular disease. HLA-B*51 subtyping did not define new markers for BD. A primary role for TNF gne polymorphisms in BD was not identified, but co-expression of the TNFB*2 allele with HLA-B*51 may contribute to severity of ocular disease.     

Association of human leukocyte antigen ancestral haplotype 8.1 with adverse outcome of non-Hodgkin's lymphoma

Previous reports have implicated the tumor necrosis factor (TNF-308) locus to non-Hodgkin's lymphoma (NHL) outcome. The purpose of the study was to examine other chromosome components of the HLA 8.1 ancestral haplotype (AH) and their relation to the clinical course of NHL. HLA class I, II, TNF-308, and lymphotoxin alpha (LTA+252) alleles were analyzed in 154 newly diagnosed NHL patients. Three locus haplotypes were inferred from the unphased genotypes by a Bayesian implementation of the expectation maximization (EM) algorithm using the PHASE 2.1 program. TNF-308A was the only allele associated with fever, poor performance status, elevated beta2-microglobulin, TNF and its p75 receptor plasma levels. Although TNF-308A was in strong linkage disequilibrium with the remaining alleles of 8.1 AH, only HLA-A*01 and HLA-B*08 showed association with prognostic variables. A part of 8.1 AH (A*01-B*08-TNF-308A) was predictive for shorter freedom from progression and overall survival (RR=2.47, P=0.041; RR=3.15; P=0.0049), an association that was stronger than TNF-308A alone and independent from International Prognostic Index (RR=1.55, P<0.001; RR=2.36; P<0.0001). A*01-B*08-TNF-308A fragment of 8.1 AH remained an independent predictive factor in a multivariate model. We conclude that 8.1 AH is an important contributor to NHL outcome. In contrast to A*01-B*08-TNF(-308A, the remaining alleles (Cw*07, DRB1*03, LTA+252G) associated with the 8.1 AH seem to be its passive components.     

Association and interaction of the TNF-alpha gene with other pro- and anti-inflammatory cytokine genes and HLA genes in patients with type 1 diabetes from North India

Type 1 diabetes (T1D) is a multifactorial autoimmune disorder where major histocompatibility complex (MHC) genes and the insulin-linked polymorphic region have been shown to play major roles. We report here an integrated effect of tumor necrosis factor (TNF) alpha with other cytokine genes. The TNF-alpha-308 GA and AA (high secretor) polymorphisms were significantly increased in the patients with T1D (n = 235) [P < 7 x 10(-6), odds ratio (OR) = 3.04, 95% confidence interval (CI) = 1.8-5.3] compared with the controls (n= 128). The variants of interferon-gamma (IFN-gamma) (A(+874)T), interleukin (IL)-6 (G(-174)C), IL-10 (A(-1082)G, T(-819)C, C(-592)A) and transforming growth factor (TGF) beta1 (T(cdn10)C, G(cdn25)C) did not show a significant difference between patients and controls. However, simultaneous presence of TNF-alpha-308 GA+AA along with both high and low secretor genotypes of IFN-gamma (P < 0.003) was significantly increased in patients. Simultaneous presence of TNF-alpha-308 GA + AA along with high secretor genotypes of IL-6 (P < 0.0001, OR = 2.61, 95% CI = 1.5-4.56), IL-10 (P < 0.0001, OR = 4.26, 95% CI = 1.9-10.1) and TGF-beta1 (P < 0.00004, OR = 2.8, 95% CI = 1.6-4.86) was also significantly increased in patients with T1D. Low secretor genotype of TNF-alpha-308 GG along with low secretor genotypes of IFN-gamma (P < 0.001, OR = 0.465, 95% CI = 0.28-0.77), high secretor genotypes of IL-6 (P < 0.000004, OR = 0.76, 95% CI = 0.227-0.621) and TGF-beta1 (P < 0.000006, OR = 0.336, 95% CI = 0.198-0.568) was protective. The TNF-alpha-308 G allele was in linkage disequilibrium (LD) with the human leukocyte antigen (HLA)-B*0801-DRB1*0301 haplotype, while TNF-alpha-308 A allele was in LD with the HLA-B*5001-DRB1*0301 and B*5801-DRB1*0301 haplotypes, suggesting that the effect of TNF-alpha -308 A allele is not because of its being in LD with any HLA alleles, but because of its functional role and its integrated effect with other cytokines.     

Association of tumour necrosis factor-alpha -308 G/A promoter polymorphism with susceptibility and disease profile of rheumatoid arthritis

The objective was to analyze the possible involvement of tumour necrosis factor-alpha (TNF-α) -308 G/A promoter polymorphism in the susceptibility and/or the disease profile of rheumatoid arthritis (RA) in Egyptian patients. TNF-α-308 G/promoter polymorphism detection by amplification refractory mutation system (ARMS) technique was carried out for 122 RA patients and 120 healthy controls. TNF-α-308 G allele/GG homozygous genotype were higher in patients with rheumatoid arthritis than those in control group (P < 0.001, respectively). A statistically significant association was found between the frequency of the A allele and presence of erosion (OR = 3.42, P = 0.015). No associations were found between the distribution of TNF-α-308 G/A alleles/genotypes and age of patients, disease duration, absence of remission, presence of deformity, clinical manifestations of the disease and presence or absence of rheumatoid factor. The positivity of rheumatoid factor was associated with occurrence of erosion (OR = 25.0, P < 0.001). The results of this study demonstrate the association of the TNF-α-308 G allele and GG homozygous genotype with susceptibility to RA and the A allele with the presence of erosion in the Egyptian patients.     

Susceptibility to multiple sclerosis mediated by HLA-DRB1 is influenced by a second gene telomeric of the TNF cluster

Susceptibility to multiple sclerosis (MS) is clearly associated with human leukocyte antigen (HLA)-DRB1*1501, but some studies show associations with HLA-B7 and -B18. These are often co-expressed with DRB1*1501 in the ancestral haplotypes (AH) denoted 7.1 (HLA-A3, B7, tumor necrosis factor [TNF]a11b4, DRB1*1501) and 18.1 (HLA-A25, B18, TNFa10b4, DRB1*1501). Here we present a systematic study of 218 patients and 274 controls typed at all standard class II and TNF microsatellite loci, and a novel non-synonymous polymorphism in the central major histocompatibility complex gene, inhibitor of κ B-like protein (IKBL). The C allele at IKBL+738 is only found on the 7.1 haplotype. HLA-DRB1*1501 was associated with disease, as expected. When subjects expressing DRB1*1501 were analyzed separately, TNFa11b4 and IKBL+738C were less common in the patients and, hence, mark an allele that mediates resistance which lies telomeric of IKBL.

TNFa10b4 and TNFa1b5 were more common in DRB1*1501 patients than in controls. These alleles have been associated with the 18.1 and 18.2 AH, respectively. Since no component of these haplotypes was an independent risk factor in this study, it appears likely that a gene linked to TNFa10b4 and TNFa1b5 modifies the effect of the susceptibility locus marked by HLA-DRB1*1501. Potential candidate genes telomeric of the TNF cluster are discussed.     

HLA class II antigens associated with lupus nephritis in Italian SLE patients

Human leukocyte antigen DR2 (HLA-DR2), namely the allelic variant HLA-DR15, have been associated with lupus nephritis (LN) in Caucasians. The study investigated the relationships between HLA class II alleles and lupus nephritis in Italian patients. Two hundred forty-four patients fulfilling the American Rheumatism Association criteria for systemic lupus erythematosus (SLE) were typed for HLA-DRB1*, -DQA1*, -DQB1*, and -DPB1* alleles by polymerase chain reaction-sequence-specific oligonucleotide and polymears chain reaction-single-strand polymorphism; 71 patients had renal damage assessed by renal biopsy. Glomerulonephritis was classified using WHO criteria. Significance was tested by X(2) on 2x2 tables. HLA-DQA1*0101 was strongly associated with LN (OR = 2.72 [1.43-5.19]; p = 0.002), whereas HLA-DRB1*1501 was only marginally associated (OR = 1.94 [0.88-4.26]; p = not significant). HLA-DQA1*0102 demonstrated a significant protective effect (OR = 0.31 [0.14-0.86]; p = 0.002). On analyzing the distribution of HLA-DRB1*1501 bearing haplotypes in our SLE patients we found that the HLA-DRB1*1501 greatly enhanced the risk of developing LN conferred by the DQA1*0101 allele (OR = 65.96 [9.35-1326.25]), whereas DQA1*0102 suppressed the nephritogenic effect of DRB1*1501. At renal biopsy, 80% of DRB1*15 positive patients were classified as having class IV LN with the remaining 20% having class III LN. The figures were 19% and 21%, respectively, among the HLA-DR15 negative patients. In the Italian population HLA-DQA and HLA-DR alleles interact in conferring susceptibility to or protection against lupus nephritis, the diffuse proliferative glomerulonephritis (i.e., the most severe form of nephritis) is associated with the HLA-DR15 bearing haplotypes.     

HLA-DMB gene and HLA-DRA promoter region polymorphisms in Australian multiple sclerosis patients.

The MHC region has been shown to contain a susceptibility locus for multiple sclerosis (MS). While the strongest association to date has been between HLA-DRB1*1501 and MS, the exact nature of the MHC association in MS remains unclear. Two candidate polymorphic loci within the MHC class II region, the HLA-DMB gene and the HLA-DRA promoter, which lie close to HLA-DRB1, were therefore examined in an Australian MS population. The HLA-DMB*0103 phenotype was increased in the MS patients (46% vs. 30%) and the frequency of the HLA-DRA promoter A allele was also increased (81% vs. 68%). When the subjects were stratified into HLA-DRB*1501 positive and negative individuals these associations were not significantly different. This is a result of the strong linkage disequilibrium between HLA-DRB*1501 and both HLA-DMB*0103 and the HLA-DRA promoter A allele. The complete linkage between DRB1*1501 and the HLA-DRA promoter A allele indicates that the MS susceptibility haplotype (DRB1*1501-HLA-DQB1*0602-HLA-DQA1* 0102) can be extended out to promoter of the HLA-DRA locus. Interactions between both HLA-DMB and the HLA-DRA promoter and other reported MS susceptibility loci were examined (TCRBV polymorphisms, HLA-DQA1 and HLA-DQB1). Some interactions between specific TCRBV polymorphisms and the HLA-DRA promoter were observed, which is consistent with other published reports suggesting an epistatic interaction between TCRBV and HLA-DRB1.