Linkage disequilibrium between HLA-DPB1 alleles and retinoid X receptor beta haplotypes

The human retinoid X receptor beta (RXRB) gene maps to the major histocompatibility complex (MHC) region, between KE4 and COL11A2, approximately 130-kb centromeric to HLA-DPB1. We have recently reported a new polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) method to detect the G to T single nucleotide polymorphism (SNP) located seven nucleotides after the tenth exon of the RXRB gene, or 3'end+7 position according to existing nomenclature. We also reported strong linkage disequilibrium between the HLA-DPB1*0401 and RXRB+7*T alleles. In the present study, we describe two PCR-RFLP methods to detect additional SNPs in the RXRB gene, T to A, at exon10+378 and A to T at 3'end+140. This new methodology permitted the unambiguous assignment of three distinct SNPs at RXRB exon10+378, 3'end+7 and 3'end+140 to form an "RXRB haplotype." The data generated from this study were used to determine linkage disequilibrium between several MHC markers and the RXRB alleles and haplotypes. Family studies revealed significant linkage disequilibrium between the RXRB alleles and a number of HLA-DPB1 alleles.     

Mutation analysis of the retinoid X receptor beta, nuclear-related receptor 1, and peroxisome proliferator-activated receptor alpha genes in schizophrenia and alcohol dependence: possible haplotype association of nuclear-related receptor 1 gene to alcohol dependence

Because retinoid cascades are involved in the regulation and development of the central nervous system, including dopaminergic neurons, retinoic acid signaling defects may contribute to schizophrenia and substances dependence. Retinoid X receptors (RXRs) form heterodimer complexes with nuclear-related receptor 1 (NURR1) or with peroxisome proliferator-activated receptors (PPARs). We examined 48 Japanese patients with schizophrenia and 32 patients with alcohol dependence to detect mutations in the retinoid X receptor beta gene (RXRB) on chromosome 6p21.3, the NURR1 gene (NR4A2) on chromosome 2q22-q23, and the PPAR alpha gene (PPARA) on chromosome 22q12.2-13.1. A Val95Ala polymorphism of the RXRB gene, a Val227Ala polymorphism in the PPARA gene, and two synonymous single-nucleotide and CA repeat polymorphisms in the 5' region and 3' untranslated region of the NR4A2 gene were identified. Extended case control samples did not suggest an association between the diseases and the RXRB or PPARA polymorphisms. However, they revealed a significant association between the NR4A2 gene haplotype and alcohol dependence, indicating that 2q22-q23 including the NR4A2 gene locus is a possible genomic region contributing to genetic susceptibility to alcohol dependence.     

Mutation analysis of the retinoid X receptor beta,nuclear‐related receptor 1, and peroxisome proliferator‐activated receptor alpha genes in schizophrenia and alcohol dependence: Possible haplotype association of nuclear‐related receptor 1 gene to alcohol dependence

Because retinoid cascades are involved in the regulation and development of the central nervous system, including dopaminergic neurons, retinoic acid signaling defects may contribute to schizophrenia and substances dependence. Retinoid X receptors (RXRs) form heterodimer complexes with nuclear‐related receptor 1 (NURR1) or with peroxisome proliferator‐activated receptors (PPARs). We examined 48 Japanese patients with schizophrenia and 32 patients with alcohol dependence to detect mutations in the retinoid X receptor beta gene (RXRB) on chromosome 6p21.3, the NURR1 gene (NR4A2) on chromosome 2q22–q23, and the PPAR alpha gene (PPARA) on chromosome 22q12.2–13.1. A Val95Ala polymorphism of the RXRB gene, a Val227Ala polymorphism in the PPARA gene, and two synonymous single‐nucleotide and CA repeat polymorphisms in the 5′ region and 3′ untranslated region of the NR4A2 gene were identified. Extended case control samples did not suggest an association between the diseases and the RXRB or PPARA polymorphisms. However, they revealed a significant association between the NR4A2 gene haplotype and alcohol dependence, indicating that 2q22–q23 including the NR4A2 gene locus is a possible genomic region contributing to genetic susceptibility to alcohol dependence. © 2001 Wiley‐Liss, Inc.     

上海汉族人群MICA基因第5外显子微卫星多态性研究

目的 了解上海地区汉族人群ＭＩＣＡ基因第５外显子微卫生多态性分布,以及ＭＩＣＡ基因与其紧密连锁的ＨＬＡ－Ｂ基因位点的关系。方法 用ＰＣＲ－异源双链分析法,对１７５名正常无关个体的ＭＩＣＡ基因第５外显子微卫星多态性的分布进行研究。结果 （１）上海地区汉族人群ＭＩＣＡ基因第５外显子存在５种等位基因,其中ＭＩＣＡ＊Ａ５最为常见（３９．１４％）,其次为＊Ａ５．１（２２．２９％）;（２）ＭＩＣＡ等位基因与Ｈ     

The existence of gender difference in IL-1Ra gene polymorphism.

Interleukin-1beta (IL-1beta) and its endogenous antagonist IL-1 receptor antagonist (IL-1ra) play an important role in various inflammatory responses. The production of IL-1 and IL-1ra is regulated by genotypic and nongenotypic factors and is different between men and women. The aim of this study was to examine the existence of gender difference in the genetic polymorphism of these two cytokines. The genotypes of IL-1beta-511 biallelic polymorphism and that of IL-1Ra (IL-1RN) penta-allelic polymorphism were determined in 319 healthy Jewish subjects, 156 female and 163 male, using PCR amplification. The results showed that there was a gender difference in IL-1Ra gene polymorphism expressed by a higher incidence of IL1RN*1/IL1RN*1 homozygotes and a lower occurrence of IL1RN*1/IL1RN*2 heterozygotes in men compared with women. Furthermore, allele IL1RN*1 was more frequent in men, whereas allele IL1RN*2 was more prevalent in women. There was no difference in IL-1beta gene polymorphism between the two genders. It is conceivable that the gender difference in IL-1Ra gene polymorphism found in the current study may affect IL-1 and IL-1ra levels. This diversity might be one of the causes for the sex differences in immune response observed in various conditions, such as autoimmune diseases, pain perception, and premature delivery.     

Human RAGE GLY82SER dimorphism and HLA class II DRB1-DQA1-DQB1 haplotypes in type 1 diabetes.

Advanced glycation end products (AGEs) are believed to play an important role in the development of diabetic complications. AGEs increase in diabetes and modulate cellular functions through binding to a specific cell surface receptor (RAGE). The RAGE gene maps to chromosome 6p in the HLA class III area and is telomeric to the class II region at 250 kb from DRA. A recent report described the characterization of a major RAGE gene variant as a biallelic single base polymorphism (G/A 557) in the exon 3 sequence leading to a change of a glycine to a serine at position 82. Using DGGE and PCR-RFLP, we have investigated the distribution of this dimorphism in conjunction with HLA class II genes in large populations of type 1 diabetic patients and healthy subjects. Although no association of this RAGE gene polymorphism with disease susceptibility was found, we report a strong linkage disequilibrium between the variant carrying the serine amino acid at position 82 and two HLA-DR2 and HLA-DR4 specificities. In particular, we describe two major extensive HLA class II haplotypes associated with this serine variant and identified as DRB1*0401-DQA1*0301-DQB1*0301 in the diabetic group and DRB1*1501-DQA1*0102-DQB1*0602 in control individuals. These data were partially confirmed by family transmission analysis.     

Alzheimer病中载脂蛋白E基因与α1—抗糜蛋白酶基因的相互 …

目的 探讨中国汉族Ａｌｚｈｅｉｍｅｒ病患者中载脂蛋白Ｅ基因多态性与α１抗糜蛋白酶基因多态性之间的关系。方法 应用聚合酶链式反应（ＰＣＲ）－限制性片段长度多态性（ＲＦＬＰ）方法,在１２５例ＡＤ患者和１４０便正常人中观察发ＡＡＣＴ信号肽基因和ＡｐｏＥ基因多态性的分布,并对ＡＡＣＰ信号肽基因多态性与ＡｐｏＥ基因ε４等位基因进行关联分析。结果 （１）ＡＡＣＴ信号肽基因多态性与ＡＤ之间不存在任何关联;（２）     

Characterization of mannose-binding lectin gene polymorphism among human T-cell lymphotropic virus 1 and 2-infected asymptomatic subjects

The present study investigated the association between mannose-binding lectin (MBL) gene polymorphism and the susceptibility to human T-cell lymphotropic virus (HTLV) infection in a group of 83 HTLV-infected asymptomatic subjects (62 HTLV-1 and 21 HTLV-2) and 99 healthy controls. Detection of MBL*A, MBL*B, and MBL*C was performed by amplifying a fragment of 349 bp (exon 1) and submitting the product to restriction fragment length polymorphism analysis with BanI and MboII endonucleases. Allele MBL*D was investigated by sequence-specific primer-polymerase chain reaction. The frequency of MBL*A, MBL*B, and MBL*D was 63%, 22%, and 15% among seropositive subjects and 70%, 14%, and 16% among healthy controls, respectively. Genotype differences were statistically significant (chi2 = 11.57; p = 0.04); the presence of genotype BB was 9.6% among HTLV-infected patients compared with 1% among controls (chi2 = 7.151; p = 0.019). A significant difference of the genotype frequencies between HTLV-1 and HTLV-2 infections was observed, but this result could be attributed to the number of investigated HTLV-1-infected subjects. The odds ratio to the presence of BB genotype was 10.453 (1.279 < or = IC95% < or = 85.40; p = 0.019). Results reveal a strong association between MBL polymorphism and HTLV infection. Presence of genotype BB may be associated with the susceptibility to HTLV, but further studies, with a larger number of individuals, will be necessary. MBL polymorphism could possibly have an impact on diseases associated with HTLV infection.     

Human RAGE GLY82SER dimorphism and HLA class II DRB1-DQA1-DQB1 haplotypes in type 1 diabetes

Advanced glycation end products (AGEs) are believed to play an important role in the development of diabetic complications. AGEs increase in diabetes and modulate cellular functions through binding to a specific cell surface receptor (RAGE). The RAGE gene maps to chromosome 6p in the HLA class III area and is telomeric to the class II region at 250 kb from DRA. A recent report described the characterization of a major RAGE gene variant as a biallelic single base polymorphism (G/A 557) in the exon 3 sequence leading to a change of a glycine to a serine at position 82. Using DGGE and PCR-RFLP, we have investigated the distribution of this dimorphism in conjunction with HLA class II genes in large populations of type 1 diabetic patients and healthy subjects. Although no association of this RAGE gene polymorphism with disease susceptibility was found, we report a strong linkage disequilibrium between the variant carrying the serine amino acid at position 82 and two HLA-DR2 and HLA-DR4 specificities. In particular, we describe two major extensive HLA class II haplotypes associated with this serine variant and identified as DRB1*0401-DQA1*0301-DQB1*0301 in the diabetic group and DRB1*1501-DQA1*0102-DQB1*0602 in control individuals. These data were partially confirmed by family transmission analysis.     

成都地区妊娠期肝内胆汁淤积症与人类白细胞抗原-DQA1的相关性研究

目的探讨妊娠期肝内胆汁淤积症（intrahepatic cholestasis of pregnancy, ICP）与人类白细胞抗原-DQA1（human leukocyte antigen-DQA1, HLA-DQA1）位点等位基因多态性的关系。方法采用聚合酶链反应-序列特异性引物法（polymerase chain reaction with sequence-specific primer, PCR-SSP）对成都地区45例ICP孕妇、18个ICP家庭、45名正常妊娠孕妇及18个正常对照家庭进行HLA-DQA1等位基因分型分析。结果ICP组孕妇HLA-DQA1＊0301等位基因频率明显低于正常对照组孕妇，除此之外，HLA-DQA1其余各等位基因的基因频率在正常对照组和ICP组之间差异无统计学意义。两组夫妇及母胎HLA-DQA1等位基因共享比较亦无统计学意义。结论成都地区人群中HLA-DQA1各等位基因与ICP的发生无明显相关性；HLA-DQA1＊0301等位基因可能是ICP的遗传保护基因，对疾病的发生可能有拮抗作用。     

Interleukin-1 receptor antagonist gene polymorphism and mortality in patients with severe sepsis

This study aims to determine the influence of the polymorphism within the intron 2 of the interleukin-1 receptor antagonist gene (IL-1RN*) on the outcome of severe sepsis, and to assess its functional significance by correlating this polymorphism with the total production of interleukin-1 receptor antagonist (IL-1Ra) protein determined in stimulated peripheral blood mononuclear cells (PBMC). A group of 78 patients with severe sepsis (51 survivors and 27 nonsurvivors) was compared with a healthy control group of 130 blood donors, and 56 patients with uncomplicated pneumonia. We found a significant association between IL-1RN* polymorphism and survival. Thus, after adjusting for age and APACHE II score, multiple logistic regression analysis showed that patients homozygotes for the allele *2 had a 6.47-fold increased risk of death (95% CI 1.01--41.47, P = 0.04). Besides, compared with patients homozygous or heterozygous for the allele *1, IL-1RN*2 homozygotes produced significantly lower levels of IL-1Ra from their PBMC. Our results suggest that insufficient production of this cytokine might contribute, among other factors, to the higher mortality rate found in severe sepsis patients with the IL-1RN*2 homozygous genotype.     

Polymorphism in gene for islet autoantigen, IA-2, and type 1 diabetes in Japanese subjects

Autoantibodies against IA-2 have been detected in up to 86% of newly diagnosed patients with type 1 diabetes and appear to identify a subgroup of prediabetic subjects who rapidly progress to type 1 diabetes. We examined the association of IA-2 gene polymorphism with type 1 diabetes in Japanese subjects. A total of 276 Japanese subjects were studied for disease association and, in addition, another 53 patients were studied for association with the autoantibody status to IA-2. A microsatellite marker D2S1753E, located in the intron of the IA-2 gene, was used as a genetic marker in this study. In Japanese, two alleles (161mu and 165mu) were more frequent, and the 163mu allele was less frequent than in Caucasians (p = 0.0001). There was no significant difference in frequencies of alleles between diabetic patients and control subjects. The frequency of IA-2 gene polymorphism was not significantly different between patients stratified by age-at-onset, or between patients with and without susceptible HLA, DRB1*0405, DRB1*0802 and DRB1*0901. There was no significant difference in allele frequency of the IA-2 gene polymorphism between patients with and without autoantibody to IA-2. In conclusion, IA-2 gene polymorphism is not associated with either susceptibility to, or heterogeneity in type 1 diabetes in Japanese subjects.     

Analysis on allelic variation of the HLA-DMB gene in Japanese by PCR-RFLP as well as direct DNA sequencing and identification of a new DMB allele, DMB*0105

In the HLA-D region, one of the class II genes, DMA and DMB have been identified between the DQ and DP genes, and four allelic polymorphisms in each of the DMA (DMA*0101–0104) and DMB (DMB*0101–0104) genes have been so far recognized. Several recent studies suggested that the DM molecule is required for class II antigen presentation pathway especially by promoting the binding of antigenic peptides to the classical HLA class II molecule. In this study, we have analyzed genetic polymorphism and allelic variation of the DMB gene in a Japanese population by the direct DNA sequencing technique and also by the polymerase chain reaction — restriction fragment length polymorphism (PCR-RFLP) method, and could recognize DMB*0101 (49.3%), DMB*0102 (23.2%), DMB*0103 (23.2%), and DMB*0104 (0.4%). Further, a new DMB allele, DMB*0105 characterized by the presence of Val and Iie at two polymorphic sites, codons 144 and 179, respectively was identified. Strong linkage disequilibria were found between DMB*0101 and DRB1*0101, DPB1*0402 and DRB1*1502, and also between DMB*0103 and DRB1*1501 and DQB1*0602. HLA-DMB genotyping using the PCR-RFLP method established here will provide accurate evaluation of the effects of sequence allelism in the DMB gene on the HLA class II disease associations.     

Genetic polymorphism in the persyn (gamma-synuclein) gene and the risk of Alzheimer's disease

Alzheimer's disease (AD) is a complex disease with the possible involvement of several genes. Genetic studies on sporadic late-onset AD have determined APOE*4 to be the major risk factor. Members of the synuclein gene family are potential candidates for the risk of AD. The persyn gene (gamma-synuclein) has recently been characterized and a common polymorphism (Glu110Val) has been identified. In this study we investigated the association of this polymorphism with sporadic late-onset AD patients. We screened DNA samples of 313 late-onset cases and 352 controls. No significant association was observed between the missense mutation and AD. When the data were stratified by APOE*4 carriers and non-APOE*4 carriers, no difference was seen for the Glu110Val polymorphism. There was also no difference in genotype or allele frequency when stratified by the ACT*A allele. Although our data show no effect of this persyn polymorphism in AD, characterization of additional polymorphisms in this gene may provide more conclusive answers.     

Polymorphism in MICA rather than HLA-B/C genes is associated with psoriatic arthritis in the Jewish population

The aim of this study was to examine whether the association of psoriatic arthritis (PsA) with human leukocyte antigen (HLA) class I genes is secondary to linkage disequilibrium with a nearby gene. We examined a sample of the Jewish population to investigate whether HLA-B/C and DR polymorphism is associated with susceptibility, or whether other closely related class I loci, such as the major histocompatibility complex class I chain-related gene A (MICA) and tumor necrosis factor (TNF), might play a role in disease development. Comparisons of different populations with different HLA profiles would be of value in identifying the candidate genes involved in PSA. Fifty-two patients with PsA and 73 random matched controls from a Jewish population were selected and DNA typed by polymerase chain reaction-single-strand oligonucleotide probe (PCR-SSOP) (HLA-C), PCR sequence-specific primers (PCR-SSP) (HLA-B, -DR), radioactive PCR (MICA-TM polymorphism in the transmembrane region), and PCR-RFLP (TNF). Some findings can be concluded from the study: (1) the frequency of HLA-B*5701, B*3801, B*39, B*27, Cw*0602, Cw*07, DRB1*0402, and DRB1*0701 were not found to be significantly increased in PsA; (2) no significant differences of TNFalpha promoter alleles at positions -308 and -238 were found between PsA and healthy controls; (3) the trinucleotide repeat polymorphism MICA-A9 was present at a higher frequency in PsA patients, (p(c) < 0.009, RR = 3.34, EF = 0.39); and (4) MICA-A9 polymorphism was found in linkage disequilibrium with HLA-B alleles (B*5701, B*3801) described to be associated with PsA in Caucasians. These results suggest that the MICA gene or other nearby gene(s) may be involved in the development of PsA, and it would thus appear that psoriasis vulgaris (PsV) and PsA are associated with different MHC susceptibility genes.     

Retinoid X receptor beta polymorphisms do not explain functional differences in vitamins D and A response in Antineutrophil cytoplasmic antibody associated vasculitis patients

It has been suggested that the retinoid X receptor beta (RXRB) gene is a risk factor for Wegener's granulomatosis. We addressed if there is a functional difference in the response to retinoic acid (RA) and vitamin D in Antineutrophil cytoplasmic antibody (ANCA) associated systemic vasculitis (AASV) patients and if this was associated with RXRB genotypes. TNFα and IL-10 production were measured in whole blood assay from AASV patients (n = 51) and healthy controls (HC, n = 67). One micromolar of 1,25-(OH)₂ D3, 9-cis RA (9c-RA) or all-trans RA (ATRA) was added to the assay. Genotyping was performed for exons 7 and 2 of the RXRB gene and for a microsatellite in vicinity of the RXRB gene. Lipopolysaccharide (LPS) mediated TNFα production and IL-10 were significantly lower in patients. Addition of 1,25-(OH)₂ D3, ATRA or 9c-RA, blunted TNFα production, more pronounced in patients. Although all three compounds inhibited IL-10 production significantly in HC, only 1,25-(OH)₂ D3 was found to be effective in patients. Allele distribution of the RXRB microsatellite differed significantly between patients and HC. This was not found for the SNP in exons 2 and 7. Genotype of the latter correlated with the ability of 1,25-(OH)₂ D3 and ATRA to inhibit IL-10 production. We provide immunological evidence for a functional difference in vitamins D and A responsiveness in AASV patients. Since the inhibition of TNFα was more effective in patients, vitamin D supplementation might be an additional therapeutical approach.     

昆明彝族人群HLA-DRB1、DQB1基因多态性

目的　调查昆明彝族 HL A- DRB1、DQB1基因的多态性。方法　应用聚合酶链反应 -序列特异性引物基因分型技术 ,对昆明地区 70名彝族健康儿童进行了 HL A- DRB1、DQB1位点的基因分型。结果在 HL A- DRB1位点共检出了 12种等位基因 ,其中等位基因频率大于 10 %的依次为 HL A- DRB1* 12 (33.5 7% )、DRB1* 0 90 1(11.4 3% )、DRB1* 0 4 (11.4 3% ) ,等位基因频率大于 5 %而小于 10 %的依次为 DRB1* 0 1(8.5 7% )、DRB1* 11(7.86 % )、DRB1* 14 (7.14 % )、DRB1* 15 (7.14 % )、DRB1* 0 8(5 % ) ,等位基因频率小于 5 %依次为 HL A- DRB1* 0 3(2 .86 % )、DRB1* 13(2 .14 % )、DRB1* 0 7(1.4 3% )、DRB1* 16 (1.4 3% )。在 HL A- DQB1位点共检出了 7种等位基因 ,其中等位基因频率大于 10 %的依次为 HL A- DQB1*0 30 1(45 % )、DQB1* 0 5 (2 2 .14 % )、DQB1* 0 30 3(12 .14 % ) ,等位基因频率大于 5 %而小于 10 %的依次为DQB1* 0 4 (6 .4 3% )、DQB1* 0 6 (6 .4 3% ) ,等位基因频率小于 5 %的依次为 DQB1* 0 2 0 1(4.2 9% )、DQB1* 0 30 2 (3.5 7% )。结论　昆明彝族 HL A基因多态性分布不同于北方汉族人群 ,也不同于南方汉族人群 ,有其独特性。     

HLA-DMA alleles are possible new markers of rheumatoid arthritis: study of a Corsican group

The HLA-DMA gene, along with the HLA-DMB gene, encodes the not classical class II molecule. This molecule catalyzes the class-II-associated invariant-chain peptide (CLIP)-antigen peptide exchange in classical class II molecule peptide-binding groove. As such, the DM heterodimer is an antigen presentation regulator and may be linked to immune system deficiencies such as those observed in autoimmune diseases. The study of DMA gene polymorphism seems be a reasonable approach to provide an answer to this question. Thanks to PCR-derived methods, the relationship between DMA gene polymorphism and rheumatoid arthritis (RA) was demonstrated in the present study. The DMA*0101 allele was observed to confer a significant predisposition to RA while the DMA*0102 allele significantly protected from this disease. Polymorphism experiments with the HLA-DRB1 gene revealed that this relationship between DMA polymorphism and RA is not a consequence of a linkage disequilibrium with the HLA-DRB1 alleles implicated in this pathology. The study of the DMA gene could therefore prove to be very useful in the early diagnosis of RA. Copyright Copyright 1999 S. Karger AG, Basel     

多发性骨髓瘤与MHC-DRB1~*基因的相关研究

目的探讨北方地区汉族人多发性骨髓瘤(MM)与人类主要组织相容性复合体MHC-DRB1*基因多态性的关系。方法应用顺序特异性引物和聚合酶链反应(PCR-SSP)技术,对21例多发性骨髓瘤患者及32例无血缘关系的健康人的MHC-DRB1*各等位基因及亚基因进行了检测分析,并将该方法与其它检测MHC等位基因的方法进行对比。结果结果表明,MHC-DRB1*11(RR=2.36,P<0.05;MHC-DRB1*11基因与MM呈正相关,显著高于对照组,两组之间比较差异有显著性意义,而其它MHC-DRB1*各等位基因未见异常,均无统计学差异。结论本项研究结果提示,MHC-DRB1*11基因可能是我国北方汉族人MM致病的易感基因,为揭示MM的发病机制中免疫遗传学作用提供了重要信息和依据。     

Celiac disease and TNF promoter polymorphisms

The possibility that genetic susceptibility to celiac disease (CD) might be influenced by tumor necrosis factor (TNF) genes polymorphism has repeatedly been put forward. To date, this has only been investigated in case-control studies and results have been contradictory. In order to avoid any possible ethnic mismatching between patients and controls, we have approached this problem studying 71 celiac families, establishing the parental haplotypes and comparing CD versus control haplotypes (the so-called AFBAC or affected family-based controls). We used DNA-based methods to screen for HLA-DRB1, -DQA1, and -DQB1 alleles, TNFalpha promoter polymorphims and TNFa and b microsatellites. The guanine-to-adenine polymorphism at position -308 of the TNFalpha gene promoter region was found associated with CD as the TNF-308A allele appeared significantly increased in frequency in CD haplotypes, and this was shown to be independent of the association between CD and the DRB1*0301,DQA1*0501,DQB1*0201 alleles. Our results indicate that at least another gene, in addition to the known association of CD with HLA class II, has a susceptibility role in this disease. This should be either TNFalpha or another polymorphic gene in the telomeric end of the HLA class III region.