Sporadic pemphigus foliaceus and class II human leucocyte antigen allele associations in the white British and Indo-Asian populations in the UK.

BACKGROUND: Pemphigus foliaceus (PF) has both genetic and environmental susceptibility factors. Current data on human leucocyte antigen (HLA) in patients with sporadic PF are limited. AIM: To better define the distribution of HLA alleles in patients with PF in the UK. METHODS: We recruited 36 patients [26 of white British (WB) descent, 10 of Indo-Asian (IA) descent] with PF who were living in the UK and 159 ethnically matched normal controls, and analysed their class II HLA DRB1 and DQB1 allele distribution. RESULTS: There was an increased frequency of DRB1*1404 in association with DQB1*0503 in IA patients with PF. The DRB1*04 allele group as a whole had an increased frequency (P < 0.001) in the WB patient group compared with controls. The alleles contributing to this significance were DRB1*0401 (P = 0.03) and DRB1*0404 (P < 0.01). CONCLUSION: This is the largest HLA association study in sporadic PF from the UK to date. There appears to be a difference in PF susceptibility alleles between WB and IA patients, highlighting the importance of racial variation in genetic susceptibility to disease development.

CTLA-4 polymorphisms are not associated with ocular inflammatory disease.

Cytotoxic T-lymphocyte-associated antigen-4 (CTLA-4) is regarded with other molecules such as HLA, PTPN22 and CARD15 as genetic master switches of autoimmunity. Single nucleotide polymorphisms (SNPs) in the genes encoding these molecules have been associated with autoimmune conditions. We analysed the SNPs -318C/T and 49A/G in CTLA-4 in patients with Behcet's disease (BD), patients with intermediate uveitis and appropriate controls. Blood was collected from 236 patients with BD from the UK and the Middle East (ME), all fulfilling the International Study Group criteria for the diagnosis of BD, and 143 patients with idiopathic intermediate uveitis were recruited from the Medical Eye Unit at St Thomas' Hospital. Samples from healthy individuals from each geographical centre were used as controls. DNA was prepared by standard methods, and SNPs -318 and 49 in CTLA-4 were detected by a polymerase chain reaction-sequence specific primers (PCR-SSP) assay using primer mixes. The results showed that there was no association with either polymorphism in patients with BD from the UK or the ME. Similarly, there was no association in patients with intermediate uveitis. Moreover, there was no association with SNP in CTLA-4 and disease manifestations in BD or outcome in patients with intermediate uveitis. Both BD and intermediate uveitis have HLA associations, but there is no difference in distribution of CTLA-4 polymorphisms that are associated with other autoimmune diseases. The lack of association with polymorphisms in CTLA-4 and other master controlling genes of autoimmunity suggests that mechanisms that mediate such a description for BD and intermediate uveitis have still to be elucidated.

Associations of major histocompatibility complex class I chain-related molecule polymorphisms with Behcet's disease in Caucasian patients.

HLA-B*51 is known to be associated with Behcet's disease (BD) in many ethnic groups. The pathogenic gene, however, may lie close to the HLA-B locus and therefore be in linkage disequilibrium with HLA-B*51. On the basis of the proximity of MIC genes to HLA-B, their expression pattern and their affinity for the activating NKG2D receptor on natural killer (NK) cells and gammadelta T cells, these molecules have been postulated as susceptibility factors in BD. DNA from 56 western European Caucasians with BD and 90 Caucasian controls were analysed by polymerase chain reaction using allele-specific primers for MICA and MICB alleles. An increased allele frequency of MICA*009 was found in the BD patient group (25.0%) when compared with the controls (7.2%). This was associated with a corresponding decrease in MICA*008 in the BD patients (36.6%) compared with the controls (46.7%), which was not significant. MICA*009 was strongly associated with the presence of HLA-B*51 in patients and controls. No significant difference in frequency of MICB alleles was found between patients and controls. Both HLA-B*51 and MICA*009 are strongly associated with BD in a pure Caucasian BD patient group, and the two alleles are in linkage disequilibrium. No MICB allele was found to associate significantly with the disease, an unexpected finding considering the close proximity of the MICA and MICB loci. Our results suggest that while MICB does not influence the development of BD, polymorphisms in MICA may be pathogenic, perhaps through the interaction with NK and gammadelta T cells.

Are cytokine gene polymorphisms associated with outcome in patients with idiopathic intermediate uveitis in the United Kingdom?

BACKGROUND/AIM: Competing levels of cytokines, either locally within the eye or systemically, may influence the eventual outcome of ocular inflammation. Polymorphism in the promoter part of the genes controlling cytokine production may result in either higher or lower production of the relevant cytokine to a given stimulus. The authors hypothesised that such polymorphisms may relate to visual outcome in patients with idiopathic intermediate uveitis. METHODS: DNA was obtained from 125 patients with idiopathic intermediate uveitis and analysed for the interleukin 10 IL-10-1082G/Alpha and IL-10-819C/T, and interferon gamma IFNgamma 874T/A gene polymorphisms. Associations with disease were calculated by both allelic frequency and haplotype analysis, and associations between ocular disease outcomes and the presence of polymorphisms were identified. A bad outcome was defined as loss of vision <6/12 Snellen in both eyes at 5 years from presentation when the eyes were quiet. RESULTS: An initial screen showed that the 874T allele of the IFNgamma gene was more prevalent in patients than controls (chi2= 7.9; p = 0.004 OR 1.7; 95% CI 1.2 to 2.6 (Pc = 0.02), whereas the IL-10-1082/-819 AT haplotype of the interleukin 10 (IL-10) gene was not. Analysis of disease outcome showed an association between IL-10-1082 AA homozygosity and bad outcome (chi2= 13; p = 0.0003). Moreover, the two cytokine polymorphisms taken together showed that up to 75% of patients with a poor visual outcome had the combined IFNgamma 874TA or TT genotype together with the IL-10-1082AA genotype (chi2= 13.2 p = 0.0008 OR 6.4; 95% CI 1.85 to 23.6 Pc = 0.1). CONCLUSION: These results show that disease outcome in intermediate uveitis may be partly determined by a complex interplay between cytokine genes and these results may have implications for future treatment with biological agents that target these cytokines.

Corneodesmosin (CDSN) gene association with psoriasis vulgaris in Caucasian but not in Japanese populations.

PSORS1 on chromosome 6p21.3, which contains the MHC, is a major susceptibility locus for psoriasis vulgaris. This region is characterized by strong linkage disequilibrium and contains the corneodesmosin (CSDN) gene, an attractive candidate for psoriasis susceptibility based on its putative biological function in keratinocyte adhesion, and HLA-Cw6, an established marker for psoriasis susceptibility. We compared two genetically independent populations in order to define the major psoriasis susceptibility gene, a British Caucasian population comprising parent-offspring trios analysed by the transmission disequilibrium test (TDT) and a Japanese case-control population. All individuals were investigated for CDSN polymorphism (+619, +1236, +1240 and +1243) and HLA-C association. Our data confirms strong association with HLA-Cw6 and CDSN allele 5 (+619T, +1240G, +1243C) in the Caucasian cohort (TDT, P = 5.4 x 10(-6)) and in addition defines this region further by identifying a high-risk CDSN haplotype (allele 5 and +1236T, P = 8.5 x 10(-8)). In contrast no association was observed in the Japanese cohort for any HLA-C or CDSN alleles. This data supports a role for the CDSN gene in Caucasian populations with psoriasis. However the lack of association with HLA-Cw6 and CDSN alleles in Japanese psoriasis patients may be because Japanese patients exhibit a form of psoriasis similar to late onset or Type II psoriasis vulgaris in contrast to early onset or Type I disease characterizing our Caucasian population.

Association of HLA-DM polymorphism with the production of antiphospholipid antibodies.

OBJECTIVE: To investigate whether variation in the HLA-DM gene is important in producing a group of pathogenic autoantibodies-antiphospholipid antibodies (aPL)-on the basis that HLA class II restricted antigen presentation is involved in the production of aPL. METHODS: HLA-DMA and DMB polymorphisms were genotyped by polymerase chain reaction combined with restriction enzyme digestion in 51 white patients with primary antiphospholipid syndrome (APS), 82 with systemic lupus erythematosus (SLE) (42 with APS and 40 without APS), and 109 healthy white controls. The association with the aPL profile was examined. RESULTS: The distribution of DMA alleles in APS patients and in patients with APS associated with SLE was significantly different from that in controls by 4x2 chi(2) test with 3 degrees of freedom (p = 0.035 and 0.011, respectively), but it was not different between SLE patients without APS and controls. The allelic distribution of DMA was also different between patients with IgG class anticardiolipin antibody or those with lupus anticoagulant (LA) and controls (p = 0.012 and 0.007, respectively) and between patients with and without LA among SLE patients (p = 0.035). All these differences included the increase in DMA*0102 in the former groups. CONCLUSIONS: The results suggest that HLA-DMA*0102 or its linked gene(s) form one of the genetic risks for the production of aPL.

Chemokine gene polymorphisms associate with gender in patients with uveitis.

Uveitis is an inflammatory condition of ocular tissue characterized by leukocyte infiltration, tissue damage, and decreased visual acuity. Chemokines have been implicated in the pathogenesis of uveitis. Polymorphisms in the genes encoding chemokines have been described as affecting chemokine production or function. We analyzed the frequency of single-nucleotide polymorphisms (SNPs) in genes encoding CCL2 (-2518 and -2076) and CCL5 (-403 and -28) in patients with Behçet's disease (BD), a systemic form of uveitis, and patients with retinal vasculitis (RV), an organ-specific form of disease. We report that there was no association between any SNP and disease. However, when segregated on the basis of gender the CCR5 -403 AA genotype was only found in male patients with BD. Similarly, CCL2 genotypes 1/2 were predominant in males, while genotype 4 was significantly associated with disease in female patients with BD. Differences in disease symptoms and severity between males and females have been described in BD and gender-specific genetic differences in chemokine gene function may be involved.

Analysis of Fc gamma receptor II (CD32) polymorphism in populations of African and South Asian ancestry reveals east-west geographic gradients of allele frequencies.

Analysis of FcgammaRIIA alleles in Pakistanis and in Trinidadians of South Asian, African and mixed ancestry revealed no significant differences between Trinidadian South Asians and Pakistanis. H131 homozygotes were more common among Trinidadian South Asians than among Africans and those of mixed ancestry. Comparison with other populations revealed east-west geographic gradients of allele frequencies.

Human Ro60 (SSA2) genomic organization and sequence alterations, examined in cutaneous lupus erythematosus.

BACKGROUND: The Ro 60 kDa protein (Ro60 or SSA2) is the major component of the Ro ribonucleoprotein (Ro RNP) complex, to which an immune response is a specific feature of several autoimmune diseases. The genomic organization and any sequence variation within the DNA encoding Ro60 are unknown. OBJECTIVES: To characterize the Ro60 gene structure and to assess whether any sequence alterations might be associated with serum anti-Ro antibody in subacute cutaneous lupus erythematosus (SCLE), thus potentially providing new insight into disease pathogenesis. METHODS: The cDNA sequence for Ro60 was obtained from the NCBI database and used for a BLAST search for a clone containing the entire genomic sequence. The intron-exon borders were confirmed by designing intronic primer pairs to flank each exon, which were then used to amplify genomic DNA for automated sequencing from 36 caucasian patients with SCLE (anti-Ro positive) and 49 with discoid LE (DLE, anti-Ro negative), in addition to 36 healthy caucasian controls. RESULTS: Heteroduplex analysis of polymerase chain reaction (PCR) products from patients and controls spanning all Ro60 exons (1-8) revealed a common bandshift in the PCR products spanning exon 7. Sequencing of the corresponding PCR products demonstrated an A > G substitution at nucleotide position 1318-7, within the consensus acceptor splice site of exon 7 (GenBank XM001901). The allele frequencies were major allele A (0.71) and minor allele G (0.29) in 72 control chromosomes, with no significant differences found between SCLE patients, DLE patients and controls. CONCLUSIONS: The genomic organization of the DNA encoding the Ro60 protein is described, including a common polymorphism within the consensus acceptor splice site of exon 7. Our delineation of a strategy for the genomic amplification of Ro60 forms a basis for further examination of the pathological functions of the Ro RNP in autoimmune disease.

The clinical importance of variation within the HLA-Bw4 complex.

BACKGROUND: Antibody screening of a patient with a failed renal transplant showed positive reactions with most, but not all HLA-Bw4-associated B-locus antigens. However, the patient's serological HLA class I type suggested the presence of HLA-Bw4. METHODS: Standard molecular techniques were used to re-type the patient and donor. ELISA antibody screening helped determine the patient's antibody specificity. RESULTS: The patient's type was HLA-B*1402,4703;Bw6 and the donor HLA-B*4703,51011;Bw4,6. Analysis of ELISA results identified three amino acids (positions 77,80,81) as the most likely epitope recognised by the patient's serum. These corresponded to HLA-B*51011 amino acid mismatches, explaining the lymphocytotoxic reactivity pattern. This epitope is located on a subgroup of the HLA-Bw4 antigen suggesting anti-Bw4 was not a sufficient description of this antibody. CONCLUSIONS: This report identifies an antibody to a sub-group of the Bw4 public specificity and also confirms the need for sequence-level analysis in the tissue-typing laboratory to determine future unacceptable mismatches.

A candidate gene analysis of three related photosensitivity disorders: cutaneous lupus erythematosus, polymorphic light eruption and actinic prurigo.

BACKGROUND: Polymorphic light eruption (PLE) is a common inherited photosensitivity disorder, which may predispose to several related but distinct conditions, including subacute cutaneous lupus erythematosus (SCLE), discoid lupus erythematosus (DLE) and actinic prurigo (AP). OBJECTIVES: To examine specific candidate genes for shared susceptibility alleles between these related phenotypes. METHODS: Eighty-five caucasian patients with annular SCLE or DLE were recruited, in addition to 102 first-degree relatives. The prevalence of PLE in both the patient and relative groups was determined by detailed interview and clinical examination. Eighty-five patients with pure PLE and 59 patients with AP were also recruited. Candidate genes were analysed by typing of single nucleotide polymorphisms of IL10 (-1082 G/A and -819 C/T), FCGR2A (131 R/H), SELE (128 S/R), ICAM1 (241 G/R and 469 E/K), IL1A (+ 4845 G/T), IL1B (-511 C/T and + 3954 C/T), IL1RN (+ 2018 T/C) and TNF (-308 G/A) using polymerase chain reaction (PCR) with sequence-specific primers and 5'-nuclease PCR. RESULTS: A significant association was found between SCLE and the rare TNF -308 A allele when compared with patients with DLE (P = 0.043), PLE (P = 0.001), AP (P < 0.001) and healthy controls (P < 0.001). However, there was strong linkage disequilibrium between TNF -308 A and the HLA A*01, B*08, DRB1*0301 haplotype. A negative association was also found between SCLE and the IL1B + 3954 T allele (P = 0.039), but the significance was lost on correction for multiple testing. CONCLUSIONS: We have demonstrated the association of SCLE with the rare TNF -308 A allele, which may be pathogenic or, alternatively, a marker allele for the extended HLA A*01, B*08, DRB1*0301 haplotype that is associated with a number of autoimmune conditions. Although many of the other loci that we chose failed to demonstrate an association, a candidate gene approach remains the most logical one, and the most likely to yield positive results in the future.

Polymorphic light eruption and the HLA DRB1*0301 extended haplotype are independent risk factors for cutaneous lupus erythematosus.

Recent evidence suggests that polymorphic light eruption (PLE) is an inherited photosensitivity disorder which may predispose to cutaneous lupus erythematosus (LE). In this study we examine the relative risk (RR) attributable to the presence of PLE, together with the effect of the major histocompatibility complex (MHC) in the development of cutaneous LE. Eighty-five Caucasian patients with annular subacute cutaneous LE (SCLE) and discoid LE (DLE) were recruited, together with 102 first degree relatives and 200 healthy local Caucasian controls. Symptoms suggestive of PLE were elicited in patients and relatives, and human leukocyte antigen (HLA) typing determined by PCR-SSP. Standard association analysis and family transmission disequilibrium testing (TDT) were then used to compare the HLA frequencies between groups. We found a significant (P < 0.05) association of the HL4 A*01, B*08, DRB1*0301 extended haplotype with both SCLE and DLE and also significant association of DLE with the HLA A*03, B*07, DRB1*15 haplotype, with a possible protective effect in SCLE for HLA B*44 and DRB1*04 (P=0.002 and 0.001 respectively). Association was observed between PLE and cutaneous LE (P < 0.001), but not between PLE and any HLA allele. From these figures we estimate, for the general population, that the RR of developing SCLE given the presence of (a) PLE, (b) DRB1*0301 and (c) both PLE and DRB1*0301 is 3.37, 5.45 and 12.03, respectively. For DLE, equivalent RRs are 3.11, 2.15 and 6.94. In conclusion, these data imply the involvement of both PLE and HLA DRB1*0301 in the development of SCLE and DLE. They form a basis for examining the genetic architecture of photosensitivity, some aspects of which may be common to both cutaneous LE and PLE.

Mapping MHC-encoded susceptibility and resistance in primary sclerosing cholangitis: the role of MICA polymorphism.

BACKGROUND & AIMS: Recent studies suggest that major histocompatibility complex-encoded susceptibility to primary sclerosing cholangitis (PSC) maps to the HLA B-TNFA region on chromosome 6p21.3. METHODS: The present study uses a standard polymerase chain reaction protocol to investigate the 16 common alleles of the MICA locus as candidates in 2 patient populations (King's College Hospital, London, and John Radcliffe Hospital, Oxford). RESULTS: The MICA*002 allele was found in 4 of 62 (6.4%) patients and none of 50 patients vs. 41 of 118 (35%) controls (pc = 0.00018, odds ratio [OR] = 0.12, and P = 0.0000016, OR = 0.0, respectively). Overall, the MICA*008 allele was more common in PSC (gene frequency 66% vs. 48% of controls, P = 0.0023, OR = 2.11). However, unlike MICA*002 in which the difference was a result of the absence of MICA*002 heterozygotes, the MICA*008 association may be caused by an increased frequency of MICA*008 homozygosity in patients (58% vs. 22%, pc = 0.000015, OR = 5.01 and 58% vs. 22%, P = 0.0000056, OR = 4.51, respectively). Though MICA*008 is found on the ancestral 8.1 haplotype, stratification analysis indicates that this association is independent of B8 and other HLA haplotypes associated with PSC. CONCLUSIONS: The MICA*002 allele has a strong dominant effect in reducing the risk of PSC, whereas the increased risk of disease associated with MICA*008 may be a recessive effect requiring 2 copies of the MICA*008 allele.

Plasma tumor necrosis factor alpha levels and the -238*A promoter polymorphism in patients with antiphospholipid syndrome.

OBJECTIVES: To explore the possible involvement of the proinflammatory and prothrombotic cytokine TNFalpha in APS by determining the plasma levels in patients and to test for association of TNFA promoter polymorphisms and HLA class II genotypes with both plasma TNFalpha and disease. PATIENTS AND METHOD: We studied 83 Caucasoid patients with APS and two groups of healthy controls. TNFalpha levels were determined in plasma from 35 patients' and 21 controls using a highly sensitive sandwich ELISA. The full patient group was genotyped together with 95 ethnically matched healthy controls. -308 and -238 TNFA promoter polymorphisms were assessed by ARMS-PCR. HLA-DQB1, DQA1 and DRB1 genotypes were determined by PCR using sequence specific primers. RESULTS: TNFalpha levels were significantly higher in patients with APS than healthy controls (median 2.95 pg/ml [range 0.51-10.75] vs. 0.95 pg/ml [0.51-1.6], respectively; p = 0.0001). Frequencies of TNFA-308*2 genotype did not differ between patients and controls. In contrast, TNFA-238*A positive genotype was more frequent in APS patients with arterial thrombosis and pregnancy loss than in controls (OR 3.7 [95% CI 1.37-10.1], p = 0.007 and OR 3.95 [95% CI 1.3-11.7], p = 0.01; respectively). DQB1*0303-DRB1*0701 haplotype was associated with TNFA-238*A in the control group (OR 96.0 [95% CI 9.6-959], p <0.0001) as well as in APS patient's group (OR 54.2 [95% CI 9.6-306.5], p <0.0001). CONCLUSIONS: Raised plasma TNFalpha levels were found in patients with APS. As a prothrombotic and proinflammatory cytokine, TNFalpha may be involved in the development of clinical features of APS. The lack of correlation between the TNFA-238 polymorphism and plasma levels associated with disease suggests that the TNF genetic marker may only indirectly relate to protein levels by virtue of allelic association with a functional marker which may reside in the HLA class II region.

HLA class II gene polymorphisms in antiphospholipid syndrome: haplotype analysis in 83 Caucasoid patients.

OBJECTIVES: We investigated the association between HLA class II haplotypes and antiphospholipid syndrome (APS). METHODS: HLA DRB1, DQB1 and DQA1 genotypes were determined by the polymerase chain reaction using sequence-specific primers in 83 Caucasoid British patients with APS. The genotype frequencies were compared between subgroups of patients and 177 healthy controls. RESULTS: DQB1*0604/5/6/7/9-DQA1*0102-DRB1*1302 and DQB1*0303-DQA1*0201-DRB1*0701 haplotypes showed significantly positive correlations with APS [P=0.0087 and P=0.0012, respectively]. The association of the former was enhanced in primary APS patients with anti-beta 2-glycoprotein I antibodies (anti-beta 2GPI) [odds ratio 6.2, 95% confidence interval (2.2-17.6), P=0.0014, corrected P=0.042]. CONCLUSIONS: These alleles and haplotypes might affect anti-ss2GPI production and APS development in different and heterogeneous fashion.

Intercellular adhesion molecule-1 gene polymorphisms in Behçet's disease.

Intercellular adhesion molecule-1 (ICAM-1) gene polymorphisms have been implicated in the susceptibility to inflammatory diseases, including multiple sclerosis and inflammatory bowel disease. The expression of both soluble and tissue ICAM-1 is increased in Behçet's disease (BD) but the contribution of ICAM-1 gene polymorphisms to this disease remains unknown. Associations with BD have been reported for genes within the MHC, including HLA-B51, TNF and MICA, but the role of non-MHC genes in BD remains largely unexplored. We have investigated the frequency of the R/G 241 and K/E 469 ICAM-1 gene polymorphisms in 83 patients with BD disease and 103 healthy controls, all of Palestinian and Jordanian descent, and demonstrated an association between BD and the ICAM-1 E469 allele (Pc = 0.046, OR = 2.1). Among patients, no association was found between the presence of ocular disease and ICAM-1 polymorphisms. While the functional correlate of this polymorphism remains unclear, this finding indicates that a genetic polymorphism in the ICAM-1 gene domain, which is independent of the MHC, may contribute to disease.

Major histocompatility complex haplotypic associations in Felty's syndrome and large granular lymphocyte syndrome are secondary to allelic association with HLA-DRB1 *0401.

OBJECTIVE: To investigate the role of HLA class I in susceptibility to Felty's syndrome (FS) and large granular lymphocyte (LGL) syndrome. METHODS: Fifty caucasoid FS patients, and 55 patients with LGL syndrome, of whom 26 had arthritis and 29 did not, were studied. Complete HLA class I and HLA-DR typing including, where relevant, DRB1*04 subtyping was carried out by molecular methods. Comparison was made with 78 unselected healthy caucasoid controls and a further 29 DRB1*0401+ individuals. RESULTS: A significant association was found between HLA-A*02 and FS [odds ratio (OR) 3.9, 95% confidence interval (95% CI) 1.8-8.4, P = 0.0004]. At the B locus, there was an association between B*44 and LGL with arthritis [OR 3.5 (1.3-9.2), P = 0.01]. For HLA-Cw*0501, there was an association with FS [OR 4 (1. 7-9.2) P = 0.0008]. For both FS and LGL with arthritis, the extended haplotype HLA-A*02;B*44;Cw*0501;DRB1*0401 was significantly associated [OR 9.5 (2.6-35), P = 0.0001; OR 4.6 (1-22.4), P = 0.05, respectively]. There was no association between HLA class I or II and LGL without arthritis. All the allelic and haplotypic associations were lost on comparison with HLA-DRB1*0401+ controls. The strongest HLA association was with HLA-DRB1*0401 for FS [OR 27.9 (10.3-75.5), P = 10(-13)], and LGL with arthritis [OR 35.4 (9.6-131. 3), P = 10(-10)]. CONCLUSIONS: The major histocompatibility locus (MHC) associations with FS reported here are due to linkage disequilibrium with HLA-DRB1*0401. LGL syndrome with arthritis shows identical class II associations with FS, although there may be subtle immunogenetic differences between the two in the class I region. One of the extended haplotypes reported in a number of studies for FS and rheumatoid arthritis (summarized as HLA-A*02;Cw*0501; B*44;TNFb5;TNFa6;TNFd4;C4A*3;C4BQ*0;DRB1*0 401;DQB1*0301) is likely to be attributable to strong primary association with HLA-DRB1*0401, rather than to epistatic interaction between these loci.

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 Behçet'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.

Factor V Leiden mutation is associated with ocular involvement in Behçet disease.

PURPOSE: Behçet disease is a systemic disease of young adults characterized by venous occlusion in both the deep venous and retinal circulations. In severe ocular disease, blindness may occur despite immunosuppressive treatment. The most common inherited risk factor for the development of idiopathic venous thrombosis is the presence of the Factor V (FV Leiden) mutation, which confers resistance to activated protein C. The association of FV Leiden with Behçet disease has been reported, but its influence on ocular disease is not known. We therefore investigated the prevalence of this mutation in patients with Behçet disease to determine its contribution to the presence and severity of ocular disease. METHODS: One hundred and six Middle Eastern patients satisfying international criteria, and 120 healthy control subjects without a history of venous thrombosis were included in the study, and patients underwent standard examination by two ophthalmologists with an interest in Behçet disease. Genomic DNA was extracted from peripheral blood leukocytes and screened for the FV Leiden mutation with the polymerase chain reaction method with sequence-specific primers (PCR-SSP). RESULTS: FV Leiden was detected in 19% (23/120) of the control population compared with 27% (29/106) of all patients with Behçet disease (P = .13). However, among patients with Behçet disease who had ocular disease (75/106), the prevalence of FV Leiden was significantly higher (32%) than it was in control subjects (P = .04). Furthermore, ocular patients with Behçet disease in whom retinal occlusive disease was observed (25/75) had the highest expression of FV Leiden (44%). CONCLUSIONS: These data suggest that FV Leiden may be an additional risk factor for the development of ocular disease and, in particular, retinal vaso-occlusion, and it may contribute to the poor visual outcome in these patients.