Linkage between rheumatoid arthritis susceptibility and the presence of HLA-DR4 and DR beta allelic third hypervariable region sequences in southern Chinese persons.

OBJECTIVE. To analyze HLA-DR and DQ associations with rheumatoid arthritis (RA) in patients from southern China. METHODS. In 66 patients and 45 controls, restriction fragment length polymorphism studies were performed using DRB, DQA, and DQB probes, and DRB allele-specific typing of polymerase chain reaction-amplified DRB DNA. RESULTS. The frequency of HLA-DR4 was significantly increased among RA patients (42.4% versus 17.8%). Increased frequencies of the DQA3 allele (77.8% versus 48.9%) and the DQB1*0302 allele (71.0% versus 46.3%), which are in linkage disequilibrium with DR4, were also found. Oligonucleotide typing showed that the amino acid sequence LLEQRRAA, spanning amino acid positions 67-74 of the DR beta molecule, was found in 19 of 49 patients and 5 of 32 controls. The main DR4 allelic subtypes found in the population were DRB1*0404 and DRB1*0405, both of which carried the sequence. There was no difference in subtype distribution between patients and controls. CONCLUSION. Chinese RA patients have an increased frequency of HLA-DR4 alleles which possess the same DRB third allelic hypervariable sequence shown to be associated with susceptibility in Caucasian RA patients.     

Association of hla–dr4-dw15 (drb1*0405) and dr10 with rheumatoid arthritis in a spanish population

Objective. To analyze the associations of HLA class II antigens with rheumatoid arthritis (RA) in a Spanish population. Methods. We used DNA oligotyping to determine DR types, DQA1 and DQB1 alleles, and DR4 variants in 70 unrelated seropositive RA patients and 189 healthy controls living in Spain. Results. A significantly higher frequency of DR4 was seen in RA patients compared with controls (relative risk [RR] = 2.40). The DR10 specificity correlated most strongly with disease susceptibility (RR = 3.84). A significant decrease in the frequency of DR7 was observed in the RA patients (RR = 0.48). DR4-Dw15 (DRB1*0405) was found to be the unique DR4 allele associated with RA (RR = 4.27, P < 0.05), whereas Dw4 (DRB1*0401) and Dw14 (DRB1*0404/0408) showed no association, and both D10 (DRB1*0402) and Dw13 (DRB1*0403/0407) were negative risk factors for the disease. Approximately one-third of the cases of RA could not be explained by the “shared epitope” hypothesis. Investigation of the DQ alleles associated with DR4 showed that the haplotype Dw15-DQ8 (DRB1*0405-DQB1*0302) was a susceptibility factor for RA (RR = 6.36, P < 0.05). Conclusion. Our results suggest that HLA class II alleles involved in RA susceptibility can vary among different Caucasian populations.     

Rheumatoid arthritis in Israeli Jews: shared sequences in the third hypervariable region of DRB1 alleles are associated with susceptibility

Rheumatoid arthritis (RA) is known to be associated with class II HLA antigens in most populations, but recent studies in Israeli Jewish patients showed no significant differences in either DR4 or DR1 between patients and controls. In a previous DR4 subset study we found DR4-Dw15 to be associated with susceptibility (RR = 9.2) but this allele occurred in only 12% of the patients. We analyzed all DRB1 genes, using the polymerase chain reaction (PCR) and hybridization with allele specific oligonucleotides, in 49 Jewish patients with RA and 40 normal Jewish controls. Six DRB1 alleles that are similar to the prototype DR4-Dw4 (DRB1*0401) appeared to contribute to the risk for developing RA. In addition to DR4-Dw15 (DRB1*0405) 2 other alleles having substitutions in codons 71 only (DR1-Dw1/DRB1*0101, DR4-Dw14.2/DRB1*0408) or in codons 70 and 71 (DRw10/DRB1*1001) gave highly significant relative risks. Together, this group, with valine in position 85, and glycine in codon 86, gave a relative risk of 11.0 (p = 0.0002). Two other alleles with the same sequence in the third hypervariable region (amino acids 67-74) but with valine in codon 86 (DR4-Dw14.1/DRB1*0404) or alanine in 85 and valine in 86 (DR1-Dw20, DRB1*0102) gave a combined risk of 3.6 (p = 0.049). Altogether these 7 alleles with similar sequences in the third hypervariable region accounted for 55.6% of the patients, with an overall relative risk of 8.6 (p = 0.00002). Our results in this population indicate that shared epitopes in the third hypervariable region of DRB1 alleles also play a role in susceptibility to RA.(ABSTRACT TRUNCATED AT 250 WORDS)     

Influence of HLA-DR genes on the production of rheumatoid arthritis-specific autoantibodies to citrullinated fibrinogen

OBJECTIVE: Antibodies directed against citrullinated fibrinogen are highly specific for rheumatoid arthritis (RA). This study was undertaken to test whether RA-associated HLA-DR alleles are associated with anti-citrullinated fibrinogen in RA patient sera and whether replacement of arginyl by citrullyl residues on fibrinogen peptides modifies their binding to HLA-DR molecules and their recognition by T cells. METHODS: Antikeratin, antifilaggrin, and anti-citrullinated fibrinogen antibodies were assayed in RA patients who had undergone HLA-DR typing. Direct assays were performed to investigate binding of citrullinated or native fibrinogen peptides (encompassing the entire alpha- and beta-chains of fibrinogen) to purified HLA-DR molecules. T cell proliferative responses to citrullinated or native fibrinogen peptides were measured in RA patients and controls. RESULTS: HLA-DRB1*0404 was associated with anti-citrullinated fibrinogen in RA sera (P = 0.002). For the RA-associated alleles HLA-DRB1*0401 and HLA-DR1, there was a nonsignificant trend toward association (P = 0.07). Multiple peptides from the alpha- and beta-chains of fibrinogen bound many HLA-DR alleles; DRB1*0404 was the best fibrinogen peptide binder. Citrullination did not influence fibrinogen peptide binding to HLA-DR or fibrinogen peptide recognition by T cells. Peripheral blood T cells that recognized native or citrullinated fibrinogen peptides were common in RA patients but not in healthy controls. CONCLUSION: The RA-associated HLA-DRB1*0404 allele is also associated with production of antibodies to citrullinated fibrinogen. DRB1*0401 and DRB1*01 tend to be associated with anti-citrullinated fibrinogen, but this is not statistically significant. Citrullination of fibrinogen peptide does not influence peptide-DR-T cell interaction. Finally, T cell proliferation in response to citrullinated or uncitrullinated fibrinogen peptides is frequent in RA patients and very infrequent in controls.     

HLA-DRB1*0404 is strongly associated with high titers of anti-cyclic citrullinated peptide antibodies in rheumatoid arthritis

OBJECTIVE:To test whether the presence of RA associated HLA-DRB1*0101, HLA-DRB1*0401 and HLA-DRB1*0404 alleles individually influences anti-cyclic citrullinated peptide antibodies (anti-CCP) production. METHODS:The frequency of anti-CCP antibodies was calculated in the sera of 260 RA patients expressing either two (double dose genotypes SE+/SE+), one (single dose genotypes SE+/SE-) or no RA associated HLA-DR alleles (SE-/SE-). Anti-CCP antibodies titers were also determined.RESULTS:RA associated HLA-DR alleles are not mandatory for production of anti-CCP. We found that 68% of SE-/SE- patients were anti-CCP positive. There was no significant difference in anti-CCP between SE negative patient (SE-/SE-) and patients expressing at least one SE (SE+/SE+ and SE+/SE-) (p=0.140). We observed no statistical difference in anti-CCP between RA patients expressing one or two SE (82% vs. 77%, p=0.577). Among SE+/SE-patients, HLA-DRB1*0404 was associated with anti-CCP with a statistically significant difference compared with SE negative patients (90% anti-CCP positive, p=0.02). HLA-DRB1*0404 was also associated with high titers of anti CCP with a statistically significant difference compared with HLA-DRB1*0401 and HLA-DRB1*0101 patients (p=0.025).CONCLUSIONS:The RA-associated HLA-DRB1*0404 allele was the most strongly associated with the presence of anti-CCP in RA sera. Moreover, HLA-DRB1*0404 patients had higher titers of anti CCP than patients with other RA associated HLA-DR alleles.     

The genotypic distribution of shared-epitope DRB1 alleles suggests a recessive mode of inheritance of the rheumatoid arthritis disease-susceptibility gene

Objective. To test whether the genotypic distribution of rheumatoid arthritis (RA)–associated DRB1 alleles suggests that the DRB1-a ssociated disease-susceptibility gene has a recessive or additive (dominant) mode of inheritance. Methods. Caucasian patients with RA and control subjects were recruited from a faculty outpatient practice. DRB1 typing was done by several DNA-based techniques: polymerase chain reaction (PCR), followed by dot-blot hybridization with sequence-specific oligonucleotides, conventional and PCR-based restriction fragment length polymorphisms (RFLPs), and a multiplex amplification–refractory mutation RFLP system. The genotypic distribution of shared-epitope DRB1 alleles was analyzed by antigen genotype frequency among patients. The analytical method postulates a linkage-disequilibrium model with a disease locus close to a marker locus and a marker allele in linkage disequilibrium with the disease-susceptibility allele. In this instance, the marker allele was defined alternatively by any DR4-g roup allele, by any DR4-g roup or DR1-g roup allele, by any DR4-g roup shared-epitope allele, by any DRC-group shared-epitope allele plus DRB1*0101, or by any shared-epitope DRB1 allele. Observed numbers were compared with those predicted for recessive mode or additive (dominant) mode of inheritance of the DRB1-a ssociated RA disease-susceptibility gene. Results. The genotypic distribution of shared-epitope DRB1 alleles (DRB1*0401, *0404, *0405, *0408, *0101, *0102, or *1001) fit that predicted for a recessive mode of inheritance and was significantly different from that predicted for an additive (dominant) mode. When the analysis was restricted to shared-epitope DR4 alleles alone (DRB1*0401, *0404, *0405, or *0408), the observed genotype numbers fit the recessive mode best. When DR1-g roup alleles were added to DR4-g roup alleles, or alternatively, when the major shared-epitope DR1 allele (*0101) was added to DR4-g roup shared-epitope alleles, there was a less significant deviation from the additive mode of inheritance. The reason for this was derived by comparison of observed genotype frequencies to those expected under Hardy-Weinberg equilibrium; there was a deficit of persons with DRB1*0401,*0101 and an excess of *0101,X. Conclusion. The genotypic distribution of shared-epitope DRB1 marker alleles suggests that the mode of inheritance of the DRB1-a ssociated disease susceptibility gene must be recessive and not additive (dominant).     

Noninherited maternal antigens do not play a role in rheumatoid arthritis susceptibility in Europe. European Consortium on Rheumatoid Arthritis Families

OBJECTIVE: It has been proposed that noninherited maternal antigens (NIMA) (HLA-DR antigens) might play a role in susceptibility to rheumatoid arthritis (RA), especially in patients who are not genetically predisposed, such as those who are HLA-DR4 and/or shared epitope (SE) negative. The present study was undertaken to test the NIMA hypothesis in a large cohort of European RA patients assembled by the European Consortium on RA Families (ECRAF). METHODS: HLA-DRB1 oligotyping was performed in families of European RA patients for whom both parents were alive. These families were consecutively recruited by the ECRAF between 1996 and 1998, for association studies. The frequencies of HLA-DR NIMA were compared with those of the noninherited paternal antigens (NIPA) after stratification for HLA-DR*04, *0401 and/or *0404, and SE status. NIMA or NIPA that coincided with inherited HLA-DR antigens were considered redundant and excluded from analysis. Calculations concerning the whole group and restricted to patients lacking parental RA were performed. RESULTS: One hundred seventy families from France (n = 81), Belgium (n = 23), Spain (n = 24), Italy (n = 19), Portugal (n = 14), and The Netherlands (n = 9) were oligotyped. The group of probands was predominantly female (88%), positive for rheumatoid factor, DR*04, and SE (71%, 58%, and 75%, respectively), and had erosive disease (75%). Parental RA was reported in 21 families. Using the NIPA as control, the frequency of HLA-DRB1*04, *0401 and/or *0404-, or SE-positive NIMA was not found to be increased in patients lacking these susceptibility alleles. The same was true when the 21 probands with parental RA were excluded from analysis. In DRB1*04-positive patients, we found no evidence of a relevant effect of HLA-DR3 or DR6 in the NIMA. CONCLUSION: Our results do not support the notion that noninherited maternal antigens have a role in susceptibility to RA in the offspring.     

Influence of the HLA-DRβ shared epitope on susceptibility to and clinical expression of rheumatoid arthritis in Chilean patients

OBJECTIVE—To analyse the influence of shared epitope positive HLA-DRB1 alleles (QKRAA or QRRAA) ) on rheumatoid arthritis (RA) susceptibility and severity in Chileans, a population that exhibits a weak association with HLA-DR4.
METHODS—Prevalence of alleles DRB1*01 and DRB1*04 alleles was determined by polymerase chain reaction amplification and sequence specific oligonucleotide hybridisation in 129 RA patients with defined clinical features and in 97 healthy controls.
RESULTS—The shared epitope was found in 70 (54%) of the RA patients and in 29 (30%) of controls (odds ratio (OR) =3; 95% confidence intervals (CI) = 1.5, 5.1; p = 0.0004), and was present in a double dose in 20% of patients versus 4% of controls (OR = 6; 95% CI = 2, 21; p = 0.0009). HLA-DRB1*0403 was the most prevalent DR4 subtype in controls (19%). HLA-DRB1*0404 or *0408 were the alleles most prominently associated with RA, 19% versus 6 % in controls (OR=3; 95% CI = 1.3, 10; p = 0.01). The risk of RA in those carrying a double dose of the shared epitope was 7.5 times that seen in patients lacking the epitope. Disease severity was moderate: 33% had extra-articular manifestations. The double dose was associated with an increased risk of vasculitis or extra-articular manifestations. However, 59 patients (46%) did not carry the shared epitope and 18 of them (31%) had extra-articular manifestations.
CONCLUSIONS—The weak association of RA with DR4 in Chileans seems to relate to a relatively high frequency of the DRB1*0403 allele among DR4 subtypes. As in other populations, the shared epitope in double dose is associated with RA development, especially in its more severe forms. However, both development and expression of severe forms of the disease were independent of the shared epitope in a high proportion of patients, thus emphasising the genetic heterogeneity of the disease and the possible involvement of other genetic elements.

     

Predominance of HLA-DRB1*0405 in Korean patients with rheumatoid arthritis.

OBJECTIVE--To identify the association of HLA-DR4 subtypes with rheumatoid arthritis (RA) in Koreans. METHODS--Ninety five patients with RA and 118 normal control subjects were examined for HLA-DR antigens by serology. Subtypes of HLA-DR4 were determined by allele specific oligonucleotide typing. RESULTS--The phenotype frequency of HLA-DR4 in RA patients was significantly greater than that in controls (60.0% versus 31.4%, odds ratio (OR) 3.28, 95% confidence interval (CI) 1.79 to 6.02 (p < 0.001)), but HLA-DR6 was decreased in RA patients (15.8% versus 32.2%, OR 0.39, 95% CI 0.19 to 0.81 (p < 0.001)). When DR4 was excluded from analysis of patients and controls, the allele frequency of DR1 was significantly increased in the patients compared with controls (11.3% versus 4.5%, OR 2.73, 95% CI 0.87 to 5.95 (p < 0.001)). Forty two of 57 DR4 positive patients (73.7%) possessed DRB1*0405, which was strongly associated with RA (44.2% of patients, versus 11.9% of controls: OR 5.88, 95% CI 2.81 to 12.47 (p < 0.001)). DRB1*0403 was not found in the patients, but was present in 8.5% of controls. Examining the third hyper-variable region at position 70-74 in the DRB1*04 chain by oligotyping, we found that 52 of 57 DR4 positive patients (91.2%) carried one of the conserved amino acid sequences QRRAA or QKRAA, known to be the epitope conferring predisposition to RA. CONCLUSION--This study confirms that RA is strongly associated with DR4, especially with DRB1*0405, and that the presence of the inferred QRRAA sequence may be important in susceptibility to RA in Koreans.     

Influence of HLA–DR genes on the production of rheumatoid arthritis–specific autoantibodies to citrullinated fibrinogen

Objective

Antibodies directed against citrullinated fibrinogen are highly specific for rheumatoid arthritis (RA). This study was undertaken to test whether RA‐associated HLA–DR alleles are associated with anti–citrullinated fibrinogen in RA patient sera and whether replacement of arginyl by citrullyl residues on fibrinogen peptides modifies their binding to HLA–DR molecules and their recognition by T cells.

Methods

Antikeratin, antifilaggrin, and anti–citrullinated fibrinogen antibodies were assayed in RA patients who had undergone HLA–DR typing. Direct assays were performed to investigate binding of citrullinated or native fibrinogen peptides (encompassing the entire α‐ and β‐chains of fibrinogen) to purified HLA–DR molecules. T cell proliferative responses to citrullinated or native fibrinogen peptides were measured in RA patients and controls.

Results

HLA–DRB1*0404 was associated with anti–citrullinated fibrinogen in RA sera (P = 0.002). For the RA‐associated alleles HLA–DRB1*0401 and HLA–DR1, there was a nonsignificant trend toward association (P = 0.07). Multiple peptides from the α‐ and β‐chains of fibrinogen bound many HLA–DR alleles; DRB1*0404 was the best fibrinogen peptide binder. Citrullination did not influence fibrinogen peptide binding to HLA–DR or fibrinogen peptide recognition by T cells. Peripheral blood T cells that recognized native or citrullinated fibrinogen peptides were common in RA patients but not in healthy controls.

Conclusion

The RA‐associated HLA–DRB1*0404 allele is also associated with production of antibodies to citrullinated fibrinogen. DRB1*0401 and DRB1*01 tend to be associated with anti–citrullinated fibrinogen, but this is not statistically significant. Citrullination of fibrinogen peptide does not influence peptide–DR–T cell interaction. Finally, T cell proliferation in response to citrullinated or uncitrullinated fibrinogen peptides is frequent in RA patients and very infrequent in controls.

     

类风湿关节炎患者抗环瓜氨酸肽抗体与人类白细胞抗原-DR4等位基因相关性研究

目的 研究类风湿关节炎(RA)及未分类关节炎(痛)(UA)患者抗环瓜氨酸肽(CCP)抗体与人类白细胞抗原(HLA)-DR4等位基因相关性.方法 对91例RA患者,46例UA患者,35名健康志愿者,均为浙江汉族人,应用酶联免疫吸附试验(ELISA)法检测血清抗CCP抗体,序列特异性引物聚合酶链反应(PCR-SSP)检测HLA-DR4等位基因.结果 RA组、UA组HLA-DR4阳性率分别为47.2%、45.6%,均以DRB1*0405为主,分别为25.3%、23.9%.RA组、UA组患者的抗CCP抗体与HLA-DR4具有相关性(r=613,0.703,P＜0.01).与HLA-DRB1*0405具有弱相关性(r=0.304,P＜0.01;r=0.333,P＜0.05). 2组HLA-DR4阳性患者抗CCP抗体水平明显高于HLA-DR4阴性患者,差异有统计学意义(P＜0.01).抗CCP抗体、HLA-DR4均阳性患者红细胞沉降率(ESR)、C反应蛋白(CRP)、血小板水平明显升高,晨僵时间延长,关节肿胀度积分升高,与二者阴性患者比较,差异有统计学意义(P＜0.05或P＜0.01).对UA组患者3个月后随访,抗CCP抗体、HLA-DR4在早期RA的阳性率为94.7%(18/19).结论 抗CCP抗体与HLADR4、DRB1*0405相关;抗CCP抗体、HLA-DR4均阳性反映了RA病情活动性;联合检测抗CCP抗体、HLA-DR4或DRB1*0405有助于RA早期诊断;抗CCP抗体可能在HLA-DR4等遗传因素参与下介导了RA发病.     

Noninherited maternal antigens do not increase the susceptibility for familial rheumatoid arthritis. European Consortium on Rheumatoid Arthritis Families (ECRAF)

OBJECTIVE: It has been proposed that noninherited maternal HLA-DR antigens (NIMA) might play a role in the susceptibility for rheumatoid arthritis (RA). This hypothesis has not been thoroughly tested in patients with familial RA, in whom genetic factors, either inherited or not, might have stronger influence than in patients with sporadic RA. We investigated the NIMA hypothesis in a large cohort of European patients with familial RA. METHODS: The distribution of NIMA, noninherited paternal antigens (NIPA), and inherited HLA-DR antigens was assessed in patients with familial RA from all family sets collected from 1996 onwards by the ECRAF. HLA-DRB1 oligotyping from patients and all available nonaffected siblings and parents was carried out. Familial RA was defined by the presence of at least 2 affected first-degree relatives in the same family. The frequencies of HLA-DR NIMA and NIPA were compared using odds ratios after stratification for HLA-DR*04, *0401, and/or *0404 and shared epitope (SE) status. NIMA/NIPA that coincided with inherited parental HLA-DR antigens were considered redundant and were excluded from analysis. RESULTS: NIMA and NIPA could be analyzed in 165 RA patients with familial RA and 84 nonaffected siblings. Patients were predominantly female, rheumatoid factor positive, and had erosive disease (81, 75, and 84%, respectively). Possession of HLA-DR*04 and *0401/*0404 alleles tended be more frequent in patients than in nonaffected siblings but this did not reach statistical significance. SE possession was similar in patients and healthy siblings, although the former had a double dose SE more often (37.6 vs 17.8%; p = 0.002). Transmission of SE encoding alleles from parents to offspring was skewed only in patients [OR (95% CI) 3.56 (2.55-4.95) vs 1.16 (0.75-1.79) in nonaffected siblings]. Using the NIPA as control, the frequencies of HLA-DRB1*04, *0401/*0404, and SE positive NIMA were not increased in patients lacking these susceptibility alleles. The frequencies of NIMA encoding susceptibility alleles in DR*04 and *0401/*0404 negative patients were lower than in nonaffected siblings. CONCLUSION: Our results corroborate the association between RA and inherited SE alleles and do not support a role for noninherited HLA-DR maternal antigens in the susceptibility for familial RA.     

HLA-DRB1 genes and disease severity in rheumatoid arthritis in Turkey

OBJECTIVE: Association with human leukocyte antigen (HLA)-DRB alleles, implicated in the aetiopathogenesis of rheumatoid arthritis (RA), is found to be different in various ethnic groups. This study aimed to investigate DRB1 alleles in RA patients in Turkey, and to examine the effect of these alleles on disease severity. METHODS: We performed PCR-based DRBI genotyping of 104 RA patients recruited from clinical settings and 110 healthy controls. HLA DRB1 alleles frequencies in RA patients and healthy controls were determined. Phenotype frequencies of patients and controls were compared. Disease severity was assessed by radiological erosion, presence of extra-articular involvement, and functional index. RESULTS: Significant differences were in the frequencies of DRB1*04 (46.2% versus 20.9%, p < 0.001), DRB1*0401 (10.6% versus 0%, p < 0.001), DRB1*0405 (8.7% versus 0%, p = 0.001), DRB1* 0404 (15.4% versus 3.6%, p < 0.01), DRB1*01 (21.2% versus 10.9%, p < 0.05) and DRB1*0101 (16.3% versus 5.5%, p = 0.01) between RA patients and controls. HLA-DRB1 alleles did not show any association with seropositivity, extra-articular involvement, radiological erosion, or functional index. CONCLUSION: Our results suggest that the HLA-DRB1 alleles, particularly HLA-DRB1*04 and subtypes, were associated with RA.     

汉族类风湿关节炎患者HLA—DR和—DQ基因分型研究

为探讨ＨＬＡ－ＤＲ和－ＤＱ等位基因与我国汉族类风湿关节炎（ＲＡ）的相关性，采用聚合酶链反应－限制性内切酶片段长度多态性分析（ＰＣＲ－ＲＦＬＰ）方法对汉族人群中３５例ＲＡ患者和１００名健康人的ＤＲ和ＤＱ位点进行ＤＮＡ定型分析。结果发现，ＤＲ４频率在正常人为２４．０％，在ＲＡ患者为５１．４％（Ｐ＜０．０１，ＲＲ＝３．３０）；ＤＲ４亚型位点分析发现２组均以ＤＲＢ１＊０４０５占多数，但ＤＲＢ１＊０４０５频率在ＲＡ组为３１．４％，高于正常人的１０．０％（Ｐ＜０．０１）。ＤＱ４频率在全部ＲＡ患者为３７．１％，在ＤＲ＋４ＲＡ患者为７２．２％，均高于全部正常人的１０．０％（Ｐ＜０．０１）和ＤＲ＋４正常人的４１．６％（Ｐ＝０．０３７６）；ＤＲ＋４－ＤＱ＋４ＲＡ患者的病情重于ＤＲ－４患者。结果提示，ＤＲ４、主要是ＤＲＢ１＊０４０５与ＲＡ相关，ＤＱ４可增加ＤＲ４对ＲＡ的易感性，ＤＲ＋４－ＤＱ＋４单倍型是ＲＡ病情严重程度的标志。     

HLA-DRB1*0404 is strongly associated with anticalpastatin antibodies in rheumatoid arthritis

Objective

To test whether HLA‐DR alleles influence the production of particular autoantibodies in rheumatoid arthritis (RA) patients, we screened synovial proteins with sera of RA patients homozygous for different HLA‐DR alleles by using 2D blots. We found that sera of RA patients homozygous for HLA‐DRB1*0404 recognised a 100‐kDa synovial protein identified as calpastatin. We studied B and T cell epitopes on calpastatin and their association with HLA‐DRB1*0404.

Methods

The frequency of positive sera in patients expressing different RA‐associated HLA‐DR allele combinations was calculated by inhouse ELISA using purified synovial calpastatin or calpastatin peptides encompassing the entire calpastatin protein as immunosorbent. Interaction between calpastatin peptides and HLA‐DR alleles was tested by a direct binding assay. T cell responses to calpastatin were measured in RA patients and controls.

Results

We found that RA‐associated HLA‐DR alleles are associated with presence of autoantibodies to synovial calpastatin in RA patients'' sera. HLA‐DRB1*0404 is strongly associated with antisynovial calpastatin in RA sera. One linear B cell epitope is preferentially associated with HLA‐DRB1*0404. Multiple peptides from calpastatin bind every tested HLA‐DR allele associated or not with RA. Peptides from domain 1 and 4 of calpastatin are the best HLA‐DR allele binders. The T cell response to calpastatin is frequent in RA patients and independent of the HLA‐DR background.

Conclusions

HLA‐DRB1*0404 is strongly associated with anticalpastatin antibodies in rheumatoid arthritis.Rheumatoid arthritis (RA) is a chronic inflammatory joint disease with a prevalence of 0.5% worldwide.¹ The aetiology of RA is unknown, but a genetic predisposition to RA is well established.² Most patients with rheumatoid arthritis express particular HLA‐DR alleles, like HLA‐DRB1*0401, *0404, *0405, *0408, *0101, *0102, *1001 and *1402. RA‐associated HLA‐DR alleles share a highly conserved amino acid motif expressed in the third hypervariable region of their DRB1 chain. This motif is called the shared epitope (SE). A dose effect has been observed in SE positive HLA‐DRB1 genotypes. Indeed, HLA‐DR genotypes containing two RA susceptibility alleles (“double dose” genotypes) confer a higher risk than genotypes containing only one susceptibility allele (“single dose genotypes”) which confer a higher risk than DR genotypes containing no susceptibility allele. The maximal risk to develop RA is observed in individuals expressing both HLA‐DRB1*0401 and HLA‐DRB1*0404. How these HLA‐DRB1 alleles influence the development of RA is unknown.To test whether HLA‐DR alleles influence the production of specific autoantibodies in RA patients, we screened synovial proteins with sera of RA patients homozygous for HLA‐DR alleles. We observed that sera from RA patients homozygous for HLA‐DRB1*0404 recognised a 100‐kDa synovial protein identified as calpastatin. Calpastatin is an endogenous calpain (calcium‐dependent cysteine protease) inhibitor, distributed in most mammalian tissues. It includes an N‐terminal L domain and four repetitive calpain inhibition domains.³ Autoantibodies against calpastatin have been previously described in rheumatoid arthritis, but their specificity remains controversial.^4,5,6,7To test the influence of different RA‐associated alleles on anticalpastatin production, we calculated the frequency of positive sera in patients expressing two, one or no RA‐associated HLA‐DR allele by inhouse ELISA using purified synovial calpastatin as immunosorbent. To identify B cell epitopes, we tested RA sera against peptides encompassing the entire calpastatin. Calpastatin comprises five domains of about 140 amino acids each. They are called domains L, 1, 2, 3 and 4. We used 94 overlapping 15 mer peptides encompassing the five domains of calpastatin to analyse RA sera reactivity. We then analysed the interaction between calpastatin peptides and HLA‐DR alleles by a direct binding assay. The 94 overlapping 15 mer peptides encompassing the five domains of calpastatin were tested for binding to purified HLA‐DRB1*0401, *0404, *0101 (RA‐associated alleles) and HLA‐DRB1*0402, *0701 (RA non‐associated alleles). Finally, we measured T cell proliferative responses to calpastatin in RA patients and controls.     

HLA-DRB1 genotype associations in 793 white patients from a rheumatoid arthritis inception cohort: frequency,severity, and treatment bias

OBJECTIVE: The HLA-DRB1 "shared epitope" (SE) genotypes are associated with rheumatoid arthritis (RA), but it remains controversial whether the association is with incidence, severity, or both, whether there are associations in seronegative patients, and whether different DRB1 alleles that contain the SE have similar effects on RA susceptibility and/or severity. The present study was undertaken to study these issues in a large cohort of patients with RA. METHODS: White patients with RA of <6 months' duration (n = 793) were enrolled in an inception cohort. HLA-DRB1 typing was performed, and patients were categorized into 21 DRB1 genotype groups. The disability index of the Health Assessment Questionnaire was the primary outcome measure. RESULTS: DRB1 associations in seronegative RA patients closely resembled those in controls. Of seropositive patients, 21% had 2 copies of the epitope, 52% had 1 copy, and 27% had none. However, not all genotypes with 1 copy were associated with increased susceptibility; for example, frequencies of DRB1*0404/X and *01/X did not differ from those in controls. Absolute differences between seropositive RA patients and controls were greatest for DRB1*0401 homozygosity (3.8% versus 0.8%, respectively) and *0401/0404 heterozygosity (4.7% versus 1.0%). DRB1*0404 was increased in frequency in seropositive RA but, unlike *0401, an increased frequency was seen only with 2 epitope copies. The relatively rare DRB1*10 had an unexpected association with seropositive RA, being present in 1.7% of seropositive RA patients and 0.7% of controls, and also showed a trend toward association with greater disease severity. The presence of 2 epitope copies was associated with increased frequency of seropositivity and younger age at disease onset, not with disease severity. Treatment indication bias was substantial and may have accounted for some of these effects. HLA-DRB1*0401/0404 was found much more frequently in men and in patients with a lower age at disease onset, and there was a trend toward a higher frequency of *0404/0401 in women. CONCLUSION: This large inception cohort study confirms previously identified major associations and provides additional insights. Only one dominant association was found: *0401, which differs from other SE alleles in a single Lys-for-Arg substitution. The association of the rare DRB1*10 allele has not previously been postulated. Sex associations were confirmed. Associations with seronegative RA were not seen. Not all genotypes containing an SE copy showed increased susceptibility to RA. The association of SE genotypes found in this study related to disease susceptibility rather than severity.     

Influence of HLA-DR alleles on rheumatoid arthritis: susceptibility and severity in Argentine patients

OBJECTIVE: To determine the frequency of shared epitopes in our population of patients with rheumatoid arthritis (RA) and to investigate whether the presence of these alleles is associated with a more aggressive form of disease. METHODS: Demographic and clinical data were obtained from 140 patients with RA, 123 female, mean age 49.9+/-11.7 years and mean disease duration 9.4+/-6.3 years. Radiographs of both hands were taken and scored by Larsen's method. HLA-DR alleles were determined by PCR-SSP. The control group comprised 202 healthy ethnic-matched subjects. RESULTS: DR4 was significantly more frequent in patients with RA than controls, and was observed in 70/140 patients (50%) versus 47/202 controls (23.27%) (odds ratio 3.25, CI 1.99-5.35, Pcorr 5 x 10(-5)). Within DR4 subtypes *0404 and *0401 were the most commonly found (37.7 and 29%, respectively). DR3 and DR11 exerted a protective effect with significantly higher frequency in controls than in patients with RA. When patients were divided into 2 groups according to disease severity (radiographic score) the frequency of alleles with QKRAA and QRRAA sequences was similar in both groups. Although with lower frequency, subtype *1001 alone was significantly more frequent in the severe-condition group [7 (13.5%) vs 3 (3.4%), p = 0.03]. CONCLUSION: These results are in accordance with findings observed in Caucasians and differ from other Latin American populations. However shared epitope alleles failed to correlate with more severe disease with the exception of subtype *1001 which, although infrequent, was significantly more frequent in patients with relevant radiological damage.     

上海地区Ⅰ型自身免疫性肝炎与HLA-DRB1等位基因的相关性研究

目的 分析HLA－DRB1等位基因与上海地区I型自身免疫性肝炎（AIH）的相关性，探讨AIH的遗传易感背景。方法 采用序列特异性多聚酶链反应（PCR－SSP），对32例I型AIH患者和48例健康对照者进行HLA－DRB1等位基因及有关基因亚型的分析。结果 HLA－DR4基因频率在I型AIH患者中较健康对照组显著增高[46.9%与20.8%；相对危险度（RR）＝3．35，χ^2=5.99,P=0.014]。其他等位基因在两组间差异无显著性。进一步对HLA－DR4等位基因亚型的分析表明，I型AIH患者组DRB1^*0405的基因频率较健康对照组有增加趋势（21．9％与6．3％，χ^2=4.23,P=0.04，但Pc=0.08)。HLA－DRβ分子的第3等位基因高变区第71位精氨酸残基的频率在I型AHI患者中显著增高（46.9%与18.8%,χ^2=7.14,P=0.008)。结论 上海地区I型AIH的发病与HLA－DR4以及HLA－DRB1第3高变区DR7位精氨酸残基相关。     

HLA haplotype analysis in Finnish patients with rheumatoid arthritis

OBJECTIVE: To further characterize the HLA gene products that play an important role in the pathogenesis of rheumatoid arthritis (RA). METHODS: One hundred thirty-four haplotypes from 67 Finnish RA patients and 77 control haplotypes were analyzed for HLA-DRB1 loci, associated alleles of the HLA-DQB1 locus, alleles of the type 2 transporter-associated antigen processing (TAP2) genes, and HLA-B27. In addition, a panel of microsatellite markers within the HLA class I and class III regions was studied. RESULTS: The frequency of HLA-DRB1*04 in the haplotypes of RA patients was found to be 34% (45 of 134) compared with 14% (10 of 72) in control haplotypes (P = 0.004). The frequency of HLA-DRB1*13 was decreased in RA haplotypes (4%, or 5 of 134) in contrast to control haplotypes (24%, or 17 of 72) (P = 0.000031). The decrease in DRB1*13 was not secondary to the increase in DRB1*04, since it was also found among DRB1*04-negative haplotypes (P < 0.001). The DRB1*13-associated DQB1*0604 allele was similarly decreased in RA haplotypes (P = 0.025). The TAP2I allele of I/J dimorphism was increased in RA patients (85%, or 114 of 134) as compared with controls (69%, or 49 of 71) (P = 0.011). Of the tumor necrosis factor (TNF) microsatellite alleles, TNFa6 and TNFb5 were found to be increased in RA haplotypes (for a6 27% versus 5% in controls [P = 0.00043], and for b5 43% versus 26% in controls [P = 0.037]). CONCLUSION: Both protection-associated and susceptibility-associated alleles can be found among HLA class II genes, and the results suggest that loci outside DR/DQ may contribute to the pathogenesis of RA.     

HLA–DRB1 genotype associations in 793 white patients from a rheumatoid arthritis inception cohort: Frequency,severity, and treatment bias

Objective

The HLA–DRB1 “shared epitope” (SE) genotypes are associated with rheumatoid arthritis (RA), but it remains controversial whether the association is with incidence, severity, or both, whether there are associations in seronegative patients, and whether different DRB1 alleles that contain the SE have similar effects on RA susceptibility and/or severity. The present study was undertaken to study these issues in a large cohort of patients with RA.

Methods

White patients with RA of <6 months' duration (n = 793) were enrolled in an inception cohort. HLA–DRB1 typing was performed, and patients were categorized into 21 DRB1 genotype groups. The disability index of the Health Assessment Questionnaire was the primary outcome measure.

Results

DRB1 associations in seronegative RA patients closely resembled those in controls. Of seropositive patients, 21% had 2 copies of the epitope, 52% had 1 copy, and 27% had none. However, not all genotypes with 1 copy were associated with increased susceptibility; for example, frequencies of DRB1*0404/X and *01/X did not differ from those in controls. Absolute differences between seropositive RA patients and controls were greatest for DRB1*0401 homozygosity (3.8% versus 0.8%, respectively) and *0401/0404 heterozygosity (4.7% versus 1.0%). DRB1*0404 was increased in frequency in seropositive RA but, unlike *0401, an increased frequency was seen only with 2 epitope copies. The relatively rare DRB1*10 had an unexpected association with seropositive RA, being present in 1.7% of seropositive RA patients and 0.7% of controls, and also showed a trend toward association with greater disease severity. The presence of 2 epitope copies was associated with increased frequency of seropositivity and younger age at disease onset, not with disease severity. Treatment indication bias was substantial and may have accounted for some of these effects. HLA–DRB1*0401/0404 was found much more frequently in men and in patients with a lower age at disease onset, and there was a trend toward a higher frequency of *0404/0401 in women.

Conclusion

This large inception cohort study confirms previously identified major associations and provides additional insights. Only one dominant association was found: *0401, which differs from other SE alleles in a single Lys‐for‐Arg substitution. The association of the rare DRB1*10 allele has not previously been postulated. Sex associations were confirmed. Associations with seronegative RA were not seen. Not all genotypes containing an SE copy showed increased susceptibility to RA. The association of SE genotypes found in this study related to disease susceptibility rather than severity.