中国内地人群类风湿关节炎与HLA-DRB1共同表位基因关联性的Meta分析

目的探讨中国内地人群类风湿关节炎(RA)与人类白细胞抗原(HLA)-DRB1共同表位(SE)基因的关联情况。方法检索已发表的有关中国内地人群RA和HLA-DRB1的文献,进行汇总分析分析。结果14项研究共纳入1118例RA患者和1301名正常对照,中国内地人群RA的关联基因有HLA-DR4[比值比(OR)=4.05,P<0.0001)]、DRB1*0401(OR=2.66,P=0.004)、DRB1*0404(OR=2.10,P=0.02)、DRB1*0405(OR=3.98,P<0.0001)、DRB1*0410(OR=3.36,P=0.008)、SE(OR=2.75,P<0.00001)。其中DRB1*0405是主要基因亚型。结论汇总分析分析不仅证实了DRB1*0405与中国内地人群RA的关联,而且发现了相对少见基因亚型DRB1*0401、DRB1*0404、DRB1*0410与RA的关联,样本大小对基因关联分析的结论有重要影响。     

中国汉族人群类风湿性关节炎与HLA-DQ基因多态性和HLA-DR-DQ连锁性的关系

目的 评价中国汉族人群类风湿性关节炎(RA)与HLA-DQ基因多态性和HLA-DR-DQ连锁性的关联情况.方法 以RA组和对照组(正常人)各HLA-DQ、HLA-DR-DQ等位基因频数分布的OR值为统计量.全面检索已发表的有关中国汉族人群RA和HLA-DQ的文献,应用Me-ta分析对基因分型研究结果进行汇总分析.结果 四项研究共入选348例RA患者和162名正常者进行对照,经Meta分析中国汉族人群RA的易感基因有HLA-DQA1*0301(OR=1.820,P=0.01)、DQB1*0401(OR=4.807,P＜0.01).DR4.DQA1*0301(OR=8.437,P=0.024)、DR4-DQB1*0401(OR=3.215,P＜0.01)在中国汉族人群RA中有连锁性并且是RA的危险基因型.HLA.DOA1*0102(OR=0.352,P=0.040)、DQB1*0602(OR=0.404,P=0.01)、DQB1*0604(OR=0,P＜0.05)是中国汉族人群RA的保护基因.结论 DQA1*0301、DQB1*0401是中国汉族人群RA的易感基因,其中DR4-DQA1*0301和DQB1*0401与DR4相连锁是RA的危险基因型,DQA1*0102、DQB1*0602和DQB1*0604是中国汉族人群RA的保护基因.     

中国内地汉族系统性红斑狼疮与HLA-DQA1基因关联研究Meta分析

目的探讨中国内地汉族人群系统性红斑狼疮(SLE)与HLA-DQA1基因的关联情况。方法检索已发表的有关中国内地汉族人群SLE和HLA-DQAl关联研究的文献,剔除不符合要求的文献,应用REVMAN4.1软件进行一致性检验和数据合并。结果研究文献质量可靠,7项研究共纳入447例SLE患者和503例正常对照,中国内地人群SLE的保护基因有HLA-DQA1*0301、P=0.00007,OR=0.64(0.52,0.80)。结论Meta分析明确了中国内地人群SLE的易感基因和保护基因,能够有效解决国人基因关联研究样本偏小所致的研究结论不一致。     

类风湿关节炎HLA-DQβ1易感基因研究

目的 探讨HLA-DQβl基因多态性在中国汉族类风湿关节炎(RA)发病中的作用及与患者临床指标的关系。方法 选取类风湿关节炎患者及健康对照各42例，以序列特异性引物PCR(PCR—SP)技术对HLA-DQβl的42种亚型进行检测，并分析患者病情、免疫学指标及关节破坏程度与各亚型之间的关系。结果 在RA患者组中HLA-DQβl*0401和*0501等位基因的频率(分别为11．9％、7．1％)显著高于对照组(分别为3．6％、1．2％)(X^2＝4．085，RR＝4．06；X^2＝4．725，RR＝6．83;P＜0．05)，而HAL-DQβ1*0602的频率则明显低于对照组(7．1％vs19．0％)(x^2＝5．23 ;P＜0．05)。HLA-DQβ*l0401／0301或*0401/0303及HLA-DQβl*0501/0301基因型在RA患者中的阳性率(分别为19．05％、9．52％)显著高于对照组(分别为2．38％、0％＞(X^2＝6．098，P＝0．014；X^2＝4．200，P＝0．040)，差异具有显著性。HLA-DQβl*03阳性的RA患者与阴性患者相比发病年龄早，关节破坏严重，关节外表现明显增多，并与部分实验室指标异常呈正相关，其中HLA-DQβ1*03纯合子(HLA-DQβl*03/03)患者的上述异常更为显著。结论 HLA-DQβl*0401及*0501亚型、HLA-DQβl*0401／03及HLA-DQβ1l*0501用301基因型可能与中国汉族RA的易感性有关，而HLA-DQβl*0602可能为抗RA基因;HLA-DQβl*03则与RA的严重程度相关。     

肺结核病患者与HLA-DRB1等位基因的关联

目的:通过对湖北省汉族肺结核病(PTB)患者进行HLA-DRB1基因分型,探讨此人群与HLADRB1的相关性。方法:用序列特异性寡核苷酸探针聚合酶链反应(PCR-SSOP)技术对174例PTB患者及1 358例健康人群进行HLA-DRB1基因分型。基因频率与Hardy-Weinberg平衡卡方检测使用arlequin软件进行,组间比较用Fisher精确概率法计算P值,检测水准为a=0.05,相对危险系数用RR表示,RR=A(A+B)/C(C+D)。结果:174例PTB患者HLA-DRB1基因分型结果与希望值进行H-W平衡检测(P0.05)。此人群检出HLA-DRB1等位基因共13种与对照组一致。其中RB1*08与DRB1*09基因频率显著高于对照组,差异有统计学意义(P0.01),且RR1,说明DRB1*08与DRB1*09或与其连锁的单倍型可能是的PTB易感基因;RB1*10与DRB1*13基因频率显著低于对照组,差异有统计学意义(P0.05),且RR1,说明RB1*10与DRB1*13可能是PTB的保护基因。其余等位基因频率组间比较均无统计学意义。结论:湖北省汉族PTB患者这个疾病群体遗传平衡被杂化,其与HLA-DRB1有一定的关联,但有其自身的特点。     

Graves病白细胞减少易感性与HLA-DRB1基因多态性的关联

目的探讨天津地区汉族Graves病(GD)白细胞减少易感性与HLA-DRB1基因多态性的关联.方法采用聚合酶链反应-序列特异性引物(PCR-SSP)方法检测45例GD白细胞减少患者、50例GD白细胞正常患者和90名正常对照的HLA-DRB1等位基因频率.结果(1)在不考虑白细胞变化的情况下,GD患者DRB1*08基因频率明显高于对照组(P＜0.01,RR=2.62),DRB1*07基因频率明显低于对照组(P＜0.01,RR=0.24).(2)GD白细胞减少组DRB1*08(P＜0.01,RR=4.17)和DRB1*15(P＜0.05,RR=1.69)基因频率较对照组显著增高,DRB1*07基因频率明显低于对照组(P＜0.01,RR=0.13).(3)GD白细胞减少组DRB1*08基因频率(P＜0.01)和DRB1*15基因频率(P＜0.05)均明显高于白细胞正常组,DRB1*09(P＜0.05)基因频率明显低于白细胞正常组.结论天津地区汉族GD白细胞减少易感性与HLA-DRB1*08,HLA-DRB1*15基因频率增加有关;GD的保护性与HLA-DRB1*07基因频率减少有关.     

山东地区汉族骨髓捐献者HLA-DRB1基因分型及多态性分析

目的观察山东地区汉族人群人白细胞抗原(HLA)-DRB1基因多态性及其分布特点。方法采用聚合酶链反应—测序为基础的分型方法(PCR-SBT)对随机抽取的909例中华骨髓库山东分库内山东汉族骨髓供者血样进行HLA-DRB1基因分型和多态性分析。结果共检测出42种HLA-DRB1等位基因,其中HLA-DRB1*0901等位基因频率最高(16.28%),其次为HLA-DRB1*1501(15.13%)和HLA-DRB1*0701(14.04%),基因频率最低的是DRB1*0408、DRB1*0809、DRB1*1103、DRB1*1303、DRB1*1412、DRB1*1425、DRB1*1601,各占0.06%。山东汉族骨髓供者HLA-DRB1等位基因的分布与江苏、湖北、新疆、广东、韩国、日本和德国人群存在明显差异(P均<0.05)。结论掌握了山东地区汉族人群HLA-DRB1基因多态性及其分布特征。     

类风湿关节炎与TLR4单核苷酸多态性关联研究的Meta分析

目的探讨类风湿关节炎(RA)与TLR4基因Asp299Gly多态性的关联情况。方法检索已发表的有关RA和TLR4基因Asp299Gly多态性的文献．进行Meta分析。结果3项研究共纳入718例RA患者和1392名正常对照，综合分析显示TLR4基因Asp299Gly多态性不是RA的关联基因，OR=1．23(0．67，2．25)，P=0．5；TLR4基因Asp299Gly多态性分布在男女性RA患者分布差异无统计学意义，OR=0．48(0．22．1．03)，P=0．06：在共同表位基因阳性和阴性患者组差异无统计学意义，OR=0．67(0．40，1．13)，P=0．13；在类风湿因子(RF)阳性和阴性患者组差异无统计学意义，OR=I．02(0．51，2．02)，P=-I；RA患者中，Asp299Asp基因型患者发病早于Asp299Gly基因型者，OR=-4．35(-7．45，-1．25)，P=0．006。结论Meta分析显示，TLR4基因Asp299Gly多态性与RA易感性无关联．但Asp299Asp基因型者起病早于Asp299Gly基因型者。应在东方人群进一步开展随机对照和前瞻的队列研究揭示其在RA发病中的作用。     

内蒙古地区汉族类风湿关节炎与HLA-DRB1基因共同表位的相关性研究

目的探讨内蒙古地区汉族人群类风湿关节炎(RA)与HLA-DRB1基因共同表位(SE)的关联性。方法采用特异性引物聚合酶链反应(PCR-SSP)方法对内蒙古地区汉族人群80例RA患者及110名正常健康者的HLA-DRB1*01、*04、*10的17个等位基因进行检测。结果内蒙古地区RA患者中携带有SE的基因频率显著高于正常对照组(48．8％：20％,P＜0．01),HLA-DR4亚型*0405是主要的易感基因(28．8％：12％,P＜0．01),其他亚型包括DRB1*0101(2．5％：0．9％),*0102(2．5％：0),*0103(1．25％：0．9％),*0104(2．5％：0％),*0401(6．25％：1．8％),*0402(3．75％：0．9％),*0403(1．25％：1．8％),*0404(2．5％：1．8％),*0406(2．5％：2．7％),*0407(1．25％：0．9％),*0408(3．75％：0．9％),*0409(1．25％：0),*0410(2．5％：0．9％),*0411(0：0)和*001(8．75％：4．5％)的差异均无统计学意义。Logistic回归分析表明：SE纯合子对RA的危害性要比杂合子大(P＜0．01)。在RA患者中。SE纯合子和SE杂合子的病程、关节肿痛数、关节压痛数、血沉(ESR),C反应蛋白(CRP)、类风湿因子(RF)、X线(Ⅲ期 Ⅳ期)与SE阴性组比较,差异有统计学意义。SE纯合子与SE杂合子相比较,各观察指标差异均无统计学意义。结论SE与内蒙古地区汉族RA易感性及疾病严重性有关。     

支气管哮喘发病与HLA-DRB1等位基因关系的研究

目的　探讨山东汉族支气管哮喘 (简称哮喘 )人群中人类白细胞抗原 (HL A) - DRB1基因型的分布 ,明确与哮喘有关的 HL A- DRB1易感基因。方法　选取急性发作期哮喘患者 (哮喘组 ) 5 0例 ,健康献血员 (对照组 )6 0例。应用序列特异性引物聚合酶链反应 (PCR- SSP)方法检测其 HL A- DRB1等位基因。结果　哮喘组 HL A-DRB1* 130 1- 130 2基因频率显著高于对照组 (P<0 .0 1) ,相对危险度 (RR)为 4 .13;其他等位基因频率两组无显著性差异 (P>0 .0 5 )。结论　 HL A- DRB1* 130 1- 130 2基因与哮喘发病相关 ,是山东汉族哮喘人群的易感基因。     

Dissection of class III major histocompatibility complex haplotypes associated with rheumatoid arthritis

OBJECTIVE: We have previously identified a single-nucleotide polymorphism (SNP) haplotype involving the lymphotoxin alpha (LTA) and tumor necrosis factor (TNF) loci (termed haplotype LTA-TNF2) on chromosome 6 that shows differential association with rheumatoid arthritis (RA) on HLA-DRB1*0404 and *0401 haplotypes, suggesting the presence of additional non-HLA-DRB1 RA susceptibility genes on these haplotypes. To refine this association, we performed a case-control association study using both SNPs and microsatellite markers in haplotypes matched either for HLA-DRB1*0404 or for HLA-DRB1*0401. METHODS: Fourteen SNPs lying between HLA-DRB1 and LTA were genotyped in 87 DRB1*04-positive families. High-density microsatellite typing was performed using 24 markers spanning 2,500 kb centered around the TNF gene in 305 DRB1*0401 or *0404 cases and 400 DRB1*0401 or *0404 controls. Single-marker, 2-marker, and 3-marker minihaplotypes were constructed and their frequencies compared between the DRB1*0401 and DRB1*0404 matched case and control haplotypes. RESULTS: Marked preservation of major histocompatibility complex haplotypes was seen, with chromosomes carrying LTA-TNF2 and either DRB1*0401 or DRB1*0404 both carrying an identical SNP haplotype across the 1-Mb region between TNF and HLA-DRB1. Using microsatellite markers, we observed two 3-marker minihaplotypes that were significantly overrepresented in the DRB1*0404 case haplotypes (P = 0.00024 and P = 0.00097). CONCLUSION: The presence of a single extended SNP haplotype between LTA-TNF2 and both DRB1*0401 and DRB1*0404 is evidence against this region harboring the genetic effects in linkage disequilibrium with LTA-TNF2. Two RA-associated haplotypes on the background of DRB1*0404 were identified in a 126-kb region surrounding and centromeric to the TNF locus.     

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.     

Analysis of single-nucleotide polymorphisms in Japanese rheumatoid arthritis patients shows additional susceptibility markers besides the classic shared epitope susceptibility sequences

OBJECTIVE: To examine the entire HLA region for loci (other than the DRB1 locus) associated with rheumatoid arthritis (RA) susceptibility, by typing HLA-DRB1 alleles and multiple single-nucleotide polymorphisms (SNPs) in the Japanese population. METHODS: The HLA-DRB1 alleles and 88 SNPs distributed over the HLA gene complex were genotyped, for 828 patients with RA and 1,032 control subjects. The data were evaluated for linkage disequilibrium, and case-control associations were analyzed in 2 ways, in the presence or absence of the disease-susceptibility DRB1 allele, to detect loci independent of the DRB1 allele. RESULTS: HLA-DRB1 alleles *0405, *0401, *0901, *0101, *1401, *1602, *0403, and *1405 were significantly associated with RA in the Japanese population. The smallest P value (P = 1.4 x 10(-27)) was observed in association with an intronic SNP of the NOTCH4 gene, which was due to strong linkage disequilibrium with the HLA-DRB1 allele. A strong association that was independent of HLA-DRB1 shared epitope alleles was observed in 2 SNPs: one in the intron of the MICA gene, the other in the intron of the HLA-DQB2 gene. Their association with RA, independent of HLA-DRB1 shared epitope alleles, was suggestive (P = 0.0024 [corrected P (P(corr)) = 0.068, and P = 0.00037 [P(corr) = 0.012], respectively). CONCLUSION: These findings suggest that 1 or more other loci besides the HLA-DRB1 or other DRB1 (non-shared epitope, non-*0901) alleles are involved in RA susceptibility/protection.     

Seronegative rheumatoid arthritis in elderly and polymyalgia rheumatica have similar patterns of HLA association

OBJECTIVE: To examine whether polymyalgia rheumatica (PMR) and late onset rheumatoid arthritis have identical or similar HLA-DRB1 genetic associations. METHODS: Seventy five PMR cases without evidence of giant cell arteritis were available for study. One hundred seven RA cases were investigated, of which 62 had disease onset after age 60 years. All cases were compared with 145 ethnically matched controls. All cases and controls originated from Lugo, NW Spain. HLA-DRB1 typing was performed on DNA samples using PCR based molecular methods. RESULTS: Early onset RA (< or =40 yrs) was strongly associated with DRB1*04 (DRB1*0401 and *0404). In contrast late onset RA (> or = 60 yrs) was not associated with DRB1*04 but was associated with DRB1*01. Stratification of late onset RA cases by rheumatoid factor status revealed that DRB1*01 was only increased in seropositive RA cases. Late onset seronegative RA cases exhibited increased frequency of DRB1*13/*14; this was also observed in PMR cases where coexistence of GCA had been excluded. CONCLUSION: These data indicate that (1) HLA associations with RA differ with respect to age at disease onset; and (2) seronegative late onset RA and "isolated" PMR have a similar HLA-DRB1 association and may have an identical etiological basis.     

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.     

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.     

Nodular disease in rheumatoid arthritis: association with cigarette smoking and HLA-DRB1/TNF gene interaction

OBJECTIVE: To investigate the association of nodular disease in rheumatoid arthritis (RA) with smoking, seropositivity, and polymorphisms at HLA-DRB1 and TNF loci. METHODS: Consecutive patients with RA (n = 420) attending a hospital clinic were examined for the presence of subcutaneous nodules. Rheumatoid factor (RF) status and HLA-DRB1 genotype were determined on every patient, and their smoking history was recorded. TNFa microsatellite polymorphisms were examined in a subgroup of 144 patients. The relationships between smoking, RF status, HLA-DRB1 genotype, TNFa microsatellite polymorphism, and the presence of nodules were examined using chi-square tests and logistic regression analyses. RESULTS: Current smokers were more likely to have nodular disease than those who had never smoked (OR 1.8, 95% CI 1.0-2.9). An association was also found between RF positivity and nodular disease (OR 2.2, 95% CI 1.2-3.8) that remained significant after correction for current smoking. A combination of current smoking and seropositivity increased the risk of nodular disease (OR 3.9, 95% CI 1.7-9.1). Analysis of HLA-DRB1 genotypes in this RA population revealed that only DRB1*0401 homozygotes were associated with nodular disease, and that this was independent of the influence of smoking and seropositivity. Individual TNFa microsatellite alleles were not associated with the presence of nodules, but an interactive effect was found between the TNF a6 allele and homozygosity for DRB1*0401. CONCLUSION: Our data indicate that nodular disease in RA is independently associated with current cigarette smoking, seropositivity, and homozygosity for HLA-DRB1*0401. The latter association involves a possible interaction with the TNF a6 microsatellite allele.     

Allelic markers close to prolactin are associated with HLA-DRB1 susceptibility alleles among women with rheumatoid arthritis and systemic lupus erythematosus

Objective. To investigate linkage disequilibrium between HLA-DRB1 disease susceptibility alleles and microsatellite markers close to the prolactin gene, among women with rheumatoid arthritis (RA) and systemic lupus erythematosus (SLE) and normal controls. Methods. DNA from 89 women with RA, 76 women with SLE, and 94 controls was typed for HLA-DRB1 status and D6S422 and D6S285, 2 highly polymorphic microsatellite markers close to the prolactin gene. RA patients were stratified by DRB1*0401 status, and SLE patients were stratified by *0301 status. Results. There was an excess frequency of D6S422*1 among SLE patients with DRB1*0301 (odds ratio [OR] 3.1). The frequency of this allele was also slightly in excess among RA patients with DRB1*0401 (OR 1.9). D6S285*5 was also in excess among female RA patients with DRB1*0401 (OR 3.5), and was slightly increased among female SLE patients with DRB1*0301. None of these alleles were found to be increased among *0401-positive or *0301-positive controls. Conclusion. These data indicate that there may be linkage disequilibrium between HLA-DRB1 alleles and microsatellite marker alleles close to the prolactin gene among women with RA and SLE. This suggests the possibility of extended haplotypes encoding for HLA-DRB1 susceptibility and high prolactin production, which contribute to susceptibility to both RA and SLE.     

MHC class I chain-related gene B (MICB) is associated with rheumatoid arthritis susceptibility

OBJECTIVES: Several recent studies have shown that the MHC class III region, located telomeric to HLA-DRB1, contains an additional genetic factor that predisposes to rheumatoid arthritis (RA). In this study, we investigate whether inhibitor of kappaB-like (IkappaBL), MICB or MICA located in the MHC class III region are the second susceptibility gene associated with RA. METHODS: A total of 154 healthy controls and 140 RA patients were genotyped for HLA-DRB1, MICA, MICB and the polymorphism -62 of the IkappaBL gene. RESULTS: A significant increase of HLA-DRB1 shared epitope (SE) alleles was detected in RA patients (61.4 vs 43.5%, P(c) = 0.01, OR = 2.1, 95% CI = 1.3-3.3). Among SE alleles, the HLA-DRB1*0401 (13.5 vs 5.1%, P(c) = 0.04, OR = 3.2, 95% CI = 1.3-8.1) and HLA-DRB1*0404 (6.4 vs 1.2%, P = 0.02, P(c) = NS) showed the most significantly association with RA. No increase of risk was associated with HLA-DRB1*01. Remarkably, the allele MICB*004 was also significantly associated with RA susceptibility (40.7 vs 23.3%, P(c) = 0.01, OR = 2.2, 95% CI = 1.3-3.7). MICB*004 was in linkage disequilibrium with HLA-DRB1*0404 (lambda(s) = 0.33) and HLA-DRB1*0405 (lambda(s) = 0.34). However, MICB*004 was also increased in HLA-DRB1 SE negative patients (37 vs 21.5%, P = 0.04). No significant association between IkappaBL and MICA with RA was found. CONCLUSIONS: MICB*004 allele was associated with RA susceptibility. This allele was in linkage disequilibrium with HLA-DRB1*0404 and DRB1*0405. The association of MICB with RA susceptibility and the functional role of MIC genes in the pathogenesis of RA converts MICB into a candidate to be an additional MHC gene associated with RA susceptibility.