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,x2=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％,x2=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AIH患者中显著增高（46.9％与 18.8％,x2=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DR71位精氨酸残基相关。     

华南地区汉族胰岛素依赖型糖尿病易感性与HLA-DR_9相关性的初步探讨

应用套式PCR检测华南地区汉族64例Ⅰ型糖尿病病人（IDDM）（包括15岁前起病组17例，15～30岁起病组30例和30岁后起病组17例）和72例健康对照者的HLA－DR9等位基因。结果：IDDM组和对照组HLA－DR9等位基因频率分别为46.9％和33．3％，无显著性差异（P＞0．05）。15岁前起病组、15～30岁起病组和30岁后起病组中HLA－DR9频率分别为58．8％、46．7％和35．3％，各组间比较P均＞0．05，15岁前起病组与对照组比较，P=0．0517。结论：本组结果未发现HLA－DR9与华南地区汉族IDDM明显相关，有待增加样本数作进一步研究。     

乙型肝炎病毒感染者人类白细胞抗原的检测

目的：探讨宿主人类白细胞抗原（HLA）Ⅱ类分子与HBV感染相关性。方法：利用PCR技术检测30例慢性乙型肝炎患者和56例HBV感染自动恢复者的HLA Ⅱ类分子及其等位基因。结果：与慢性乙型肝炎患者相比，HLA Ⅱ类分子DR12在恢复者中的分布频率显著增高（10％比38％，rr,0.19;P矫正＜0．025）；HLA－DR12的等位基因DRB1＊1201的分布频率也显著增高（3％比32％；rr,0.07;P矫正＜0．005）。而R9（43％比18％；rr,3.52;P矫正＜0．025）和DQ9（43％比20％；rr,3.13;P矫正＜0．05）在慢性乙型肝炎患者中的分布频率显著高于恢复者。结论：HLA－DR12和DRB1＊1201可能对机体免受HBV长期感染有保护性意义。而HLA－DR9或DQ9可能使宿主易发生HBV持续感染。     

HLA—DRB和ACE基因与肺结核的相关性分析

目的探讨人类白细胞抗原（HL气）-DRB基因和血管紧张素转换酶（ACE）基因多态性与肺结核的相关性。方法采用聚合酶链反应-序列特异性引物法（PCR—SSP）对肺结核组和健康对照组进行HLA-DRB和ACE基因分型。结果肺结核组HLA—DRB1＊15等位基因的频率显著高于对照组（P〈0．05）；复治和耐药肺结核组ACE基因的I／D基因型频率显著高于初治和无耐药组（P〈0．05）。结论HLA—DRB1＊15等位基因及ACE基因的I／D基因型与肺结核密切相关。     

中国北方汉族人群HLA-A、HLA-B、HLA-DR等位基因频率检测及其临床意义

目的从基因水平了解中国北方地区汉族人群人类白细胞抗原HLA—A、HLA—B、HLA—DR位点的等位基因(以下分别简称为A等位基因、B等位基因及DR等位基因)频率,获得更完整、准确的HLA群体遗传学数据。方法应用聚合酶链反应一序列特异性引物(PCR—SSP)方法对2000名北方汉族健康志愿者进行A、B、DR等位基因分型。结果鉴定了17个A等位基因,32个B等位基因,13个DRB1等位基因。最常见的基因型分别为A^ 02、B^ 13、DRB1^ 15,其相应基因频率范围分别为0．2400～0．2767、0．1330～0．1432和0．1557～0．1707。结论本结果可作为我国HLA多态性研究的群体资料和正常参考值,对群体遗传、疾病关联研究以及寻找HLA相合的异基因造血干细胞供者具有重要意义。     

HLA—DRB和ACE基因与肺结核的相关性分析

目的 探讨人类白细胞抗原（HLA）-DRB基因和血管紧张素转换酶（ACE）基因多态性与肺结核的相关性。方法采用聚合酶链反应-序列特异性引物法（PCR—SSP）对肺结核组和健康对照组进行HLA—DRB和ACE基因分型。结果肺结核组HLA—DRB1＊15等位基因的频率显著高于对照组（P〈O．05）；复治和耐药肺结核组ACE基因的I／D基因型频率显著高于初治和无耐药组（P〈O．05）。结论HLA—DRB1＊15等位基因及ACE基因的I／D基因型与肺结核密切相关。     

血管紧张素转换酶基因I/D多态性及醛固酮合成酶基因T-344C多态性与蒙古族人群原发性高血压的相关性研究

目的研究血管紧张素转换酶（ACE）基因及醛固酮合成酶（CYP11B2）基因多态性与蒙古族原发性高血压（EH）的关系。方法应用PCR-RFLP技术检测98例EH患者与正常对照组108名健康受试者ACE基因第16内含子I/D多态性及CYP11B2基因T-344C多态性。结果①蒙古族人ACE基因I/D位点II、ID、DD基因型频率在EH组和正常对照组分别为0.44、0.38、0.18和0.42、0.32、0.26，差异无显著性（χ^2=1.693，P=0.192）；②I、D等位基因的频率分别为0.63、0.37和0.58、0.42，差异无显著性（χ^2=0.808，P=0.363）；③CYP11B2T-344C位点TT、TC、CC基因型的频率在EH组和正常对照组分别为0.46、0.44、0.09和0.37、0.54、0.09，两组之间差异无显著性（χ^2=0.005，P=0.945）。④T、C等位基因频率分别为0.69、0.31和0.64、0.36，差异无显著性（χ^2=0.928，P=0.335）；⑤同时分析CYP11B2基因T-344C基因型与ACE基因I/D基因型在蒙古族人群患EH方面无协同作用。结论ACE基因I/D位点及CYP11B2基因T-344C位点与蒙古族人群患EH无相关性。     

GD药物引起粒细胞减少与等位基因的关系

采用多聚酶链式反应-序列特异引物（per—ssp）方法检测65例GD病人抗甲状腺药物引起粒细胞减少（1）组，65例GD病人并发粒细胞减少（2）组，65例非GD病人粒细胞减少（3）组，65例正常参照人群（4）组的HLA—DRB1＊08032 DRB1＊1501的等位基因频率。结果1：（1）组HLA—DRB1＊08032 DRB1＊1501的基因频率高于（2）组（P〈0．05）。2：（1）组HLA—DRB1＊08032 DRB1＊1501的基因频率明显高于（3）组（4）组，（P〈0．01）。3：（2）组HLA—DRB1＊08032 DRB1＊1501的基因频率高于（4）组（P〈0．05）。结论：GD病人应用抗甲状腺药物引起粒细胞减少与HLA—DRB1＊08032 DRB1＊1501等位基因频率增加有关。     

原发性胆汁性肝硬化患者人类白细胞抗原等位基因多态性分析

目的探讨原发性胆汁性肝硬化(PBC)患者人群与人类白细胞抗原(HLA)Ⅰ类(A、B)、Ⅱ类(DRB1)等位基因的相关性,同时评估易感基因是否与一些临床及实验室特征存在联系。方法利用序列特异性聚合酶链反应(SSP-PCR)对65例确诊的PBC患者和431名健康人进行HLA—A、B和DRB1 等位基因以及有关基因亚型分析。结果PBC患者DRB1*07的频率增高到29.2%,与正常人13.9%的频率相比,差异具有统计学意义(Pc<0.05,OR=2.55,95%CI:1.4～4.6);所有DRB1*07阳性患者经亚型分析均为DRB1*0701。未发现DRB1*08与PBC有关联性。Ⅰ类抗原中以A*2在PBC患者组的频率最高(53.8%),稍高于对照组,但无统计学意义。其余HLA-A、B和DRB1的等位基因频率与正常人相比较,差异无统计学意义。DRB1*0701阳性患者与阴性患者在一些临床、实验室指标上差异并不明显。结论PBC与HLA-DRB1*0701基因相关,与南美、北美、北欧、日本等其他国家PBC患者的易感基因明显不同;HLA-DRβ1第78位上的缬氨酸残基可能与PBC发病相关。     

HLA-DR基因与中国南方汉族部分人群肺结核易感基因的研究

目的　探讨人类白细胞抗原 (HLA) DR基因与中国南方汉族部分人群肺结核发病的关联性 ,并寻找与肺结核发病可能相关的HLA易感基因。方法　采用病例 对照的研究方法 ,应用聚合酶链反应 序列特异性引物 (PCR SSP)技术对 110例中国南方汉族肺结核患者 (肺结核病例组 )和 10 1例中国南方汉族健康对照者 (健康对照组 )的 2 3个HLA DR等位基因进行分型 ,比较其等位基因频率(GF)并计算其比值比 (OR)。结果　HLA DR基因PCR SSP分型显示 :(1)肺结核病例组中的DR16等位基因的基因频率显著高于健康对照组 ,两组的GF值分别为 12 6 2 %、5 6 0 % ,两者之间差异具有显著性 (χ2 =5 915 ,PC<0 0 5 ,OR值为 2 5 3)。 (2 )肺结核病例组中的DR1、DR13 3等位基因的基因频率分别为 8 0 8%、2 3 5 7% ,显著低于健康对照组的 2 9 2 9%、5 0 2 4 % ,两组比较 ,差异具有显著性 (χ2值分别为 17 84 7和 14 2 5 8,PC 值均 <0 0 1;OR值分别为 0 2 6、0 33)。结论　 (1)DR16等位基因与南方汉族部分人群的肺结核发病可能密切相关 ,或与真正起作用的易感基因连锁。 (2 )中国南方汉族部分人群DR1、DR13 3等位基因的表达对结核分枝杆菌感染者的发病可能具有拮抗作用。     

Relationship between human leukocyte antigen-DRB1 and autoimmune hepatitis type I in Chinese patients

AIM: To analyze the association of human leukocyte antigen (HLA)-DRB1 with autoimmune hepatitis type I (AIH) among Chinese patients in the Shanghai area. METHODS: In 32 patients and 48 healthy controls, polymerase chain reaction amplified with sequence-specific primers (PCR-SSP) was performed to elucidate the relevance of certain alleles or polymorphic sequences of HLA-DRB1 with autoimmune hepatitis. RESULTS: The HLA-DRB1 typing by PCR-SSP showed that DR4 had a significantly increased frequency among patients with AIH versus that of healthy controls (46.9 vs 20.8%; relative risk = 3.35, P = 0.014). In the subtypes of DR4, there was a trend of an increase in the gene frequency of DRB1*0405 in patients with AIH versus that of healthy controls (21.9 vs 6.3%, P = 0.04, but corrected P (Pc) = 0.08). In addition, our analysis indicated a significant increase in the alleles frequency encoding Leu-Leu-Glu-Gln-Lys-Arg (LLEQRR) from the third hyperpolymorphic region (HVR3) of DR4 in the patients with AIH (86.7% of DR4 positive patients vs 40.0% in DR4 positive controls, P = 0.016, Pc = 0.028, relative risk (RR) = 9.75). CONCLUSION: Type I AIH among Chinese patients is associated with HLA-DR4. There is a relevance of type I AIH and LLEQRR sequence within the third hyperpolymorphic region of the DRB1 allele.     

Relationship between autoimmune hepatitis and HLA-DR4 and DRbeta allelic sequences in the third hypervariable region in Chinese

AIM: To analyze the association of HLA-DRB1 with autoimmune hepatitis (AIH) in patients from China. METHODS: In 32 patients and 48 healthy controls, polymerase chain reaction amplification with sequence-specific primers (PCR-SSP) was performed to examine the association of certain alleles or polymorphic sequences of HLA-DRB1 with AIH. RESULTS: HLA-DRB1 typing by PCR-SSP showed that DR4 had a significantly increased frequency among patients with AIH versus healthy control (46.9% versus 20.8%; relative risk = 3.35, P=0.014). In subtypes of DR4, there was a trend of increase in the gene frequency of DRB1 0405 in patients with AIH versus healthy controls (21.9% vs 6.3%, P=0.04, but P(c) =0.08). In addition, a significant increase was found in the alleles frequency encoding QRRAA from the third hyperpolymorphic region of DR4 in the patients with AIH (86.7% of DR4 positive patients vs 40.0% in DR4 positive controls, P=0.016, P(c)=0.028, RR=9.75). CONCLUSION: AIH in Chinese is associated with HLA-DR4.There is a relationship between QRRAA sequence within the third hyperpolymorphic region of the DRB allele and AIH in Chinese.     

Relationship between autoimmune hepatitis and HLA-DR4 and DRβ allelic sequences in the third hypervariable region in Chinese

AIM To analyze the association of HLA-DRB1 withautoimmune hepatitis(AIH)in patients from China.METHODS In 32 patients and 48 healthy controls,polymerase chain reaction amplification with sequence-specific primers(PCR-SSP)was performed to examine theassociation of certain alleles or polymorphic sequences ofHLA-DRB1 with AIH.RESULTS HLA-DRB1 typing by PCR-SSP showed that DR4had a significantly increased frequency among patientswith AIH versus healthy control(46.9% versus 20.8%;relative risk=3.35,P=0.014).In subtypes of DR4,therewas a trend of increase in the gene frequency of DRB1~*0405 in patients with AIH versus healthy controls(21.9%vs 6.3%,P=0.04,but P_c=0.08).In addition,asignificant increase was found in the alleles frequencyencoding QRRAA from the third hyperpolymorphic regionof DR4 in the patients with AIH(86.7% of DR4 positivepatients vs 40.0% in DR4 positive controls,P=0.016,P_c=0.028,RR=9.75).CONCLUSION AIH in Chinese is associated with HLA-DR4.There is a relationship between QRRAA sequencewithin the third hyperpolymorphic region of the DRB alleleand AIH in Chinese.     

Molecular subtypes of the HLA-DR antigens in pulmonary tuberculosis.

OBJECTIVE: The aim of this study was to analyze association between HLA-DRB1 alleles and pulmonary tuberculosis (PTB) in the Polish population. METHODS: The HLA-DRB1 typing was performed using sequence-specific amplification (polymerase chain reaction with sequence specific primer [PCR-SSP] in 31 patients and 58 healthy volunteers. The DRB1 primers were supplied by DYNAL in the standard kit DYNAL DR "low-resolution"-SSP. RESULTS: The study showed that the DRB1*16 alleles frequency was higher in patients with PTB than in the tested group of healthy controls (P < 0.01). When HLA-DR2 alleles were combined (i.e., the DRB1*15 with DRB1*16 alleles), their frequency was comparable with that in the healthy individuals. The highest relative risk (RR) of tuberculosis was associated with DRB1*16 alleles (RR = 9.7). When HLA-DR6 alleles were combined (i.e., the DRB1*13 with DRB1*14 alleles), only a trend for higher frequency in patients with PTB was found. Frequency of DRB1*13 alleles of HLA-DR6 was significantly lower in PTB than in the healthy individuals (P < 0.001; RR = 0.04). CONCLUSIONS: Results suggest that the presence of HLA-DRB1*16 alleles may increase the risk of development of PTB, whereas HLA-DRB1*13 alleles may be resistant to tuberculosis.     

Genetic heterogeneity in susceptibility to autoimmune hepatitis types 1 and 2

OBJECTIVE: Susceptibility to autoimmune hepatitis (AIH) type 1 has been associated with DRB1*03, DRB1*04, and DRB3 alleles in European and North-American whites, with DRB1*04 in Japan, and with DRB1*04 and DRB1*13 in Latin America. Very few studies have been performed on AIH type 2. The aim of the present study was to evaluate the association of AIH types 1 and 2 with HLA-DR and DQ loci. METHODS: We performed HLA-DRB and -DQB1 typing by polymerase chain reaction amplification with sequence-specific primers (PCR-SSP) in 139 AIH patients. Most had AIH type 1 associated with circulating anti-smooth muscle antibody with F-actin specificity or antinuclear antibody. Twenty-eight patients presented AIH type 2 with anti-liver/kidney microsome type 1 or anti-liver cytosol type 1 antibodies. RESULTS: We observed a significant increase of DRB1*13 (70% vs 26% of controls, p < 0.00001) and DRB3 (93% vs 69% of controls, p < 0.00001) in AIH type 1 patients. Analysis of patients without DRB1*13 disclosed a secondary association with DRB1*03 (70% vs 30% of controls, p = 0.0001) and either the DRB1*13 or the DRB1*03 alleles were present in the majority of these patients (91% vs 48% of controls, p = 0.001). Comparison of DRB1*13- and DRB1*03-positive subjects revealed that the former alleles conferred susceptibility to younger patients with AIH type 1. DQB1 typing showed a significant increase in DQB1*06 (68% vs 41% of controls, p = 0.00007) in strong linkage disequilibrium with DRB1*13, and a decrease in DQB1*0301 (8% vs 47% of controls, p(c) = 0.0003). On the other hand, HLA typing of patients with AIH type 2 disclosed a significant increase in the DRB1*07 (68% vs 20% of controls, p(c) < 0.00014), DRB4 (79% vs 43% of controls, p(c) = 0.004), and DQB1*02 (86% vs 42%, p = 0.00002) alleles. After exclusion of DRB1*07, a secondary association with HLA-DRB1*03 was further observed in these patients (78% vs 30%, p = 0.007) and most of them had either DRB1*07 or DRB1*03 (93% vs 44% of controls, p(c) < 0.0001). CONCLUSIONS: Our data indicate that predisposition to AIH types 1 and 2 is associated, respectively, with the DRB1*13 or DRB1*03 and DRB1*07 or DRB1*03 alleles, and suggest that protection against type 1 disease may be conferred by DQB1*0301. In addition, the cluster of DRB1*13 in children with AIH type 1 also supports the concept that different HLA alleles might influence the onset of the disease.     

Aplastic anemia is associated with HLA-DRB1*1501 in northern Han Chinese

It has been reported that aplastic anemia (AA) is more common in HLA-DR2-positive individuals than in the general population. We investigated the frequency of some HLA loci of 102 Northern Han Chinese patients with AA and 105 healthy control subjects. Polymerase chain reaction and sequence specific oligonucleotide probe hybridization were used to determine HLA-DR- and HLA-DR2-related DRB1 alleles. The frequency of DR2 is increased in AA patients; the relative risk (RR) was 2.86, and the difference was significant (chi 2 = 11.1, P = .004). The RR of HLA-DRB1*1501 was 3.07, and the difference was significant (chi 2 = 9.42, P = .008). The above results suggest that HLA-DR2 is significantly associated with AA in Northern Han Chinese. HLA-DRB1*1501 is the main subtype of HLA-DR2, and may be the susceptibility gene of AA.     

Association of the HLA-DRB1 gene with susceptibility to aortoarteritis in a Chinese Han population.

Aortoarteritis is a chronic inflammatory disease mainly affecting the aorta and its major branches. Recent immunogenetic studies indicate that certain human leucocyte antigen (HLA) alleles are significantly associated with aortoarteritis in several populations. The purpose of the present study was to investigate the relationship between the HLA-DRB1 alleles and aortoarteritis in a Chinese Han population. HLA-DRB1 genotypes were identified by PCR-SSP and PCR-RFLP in 84 Chinese patients with aortoarteritis and 102 healthy Chinese controls. It was found that the HLA-DRB1*04 allele (38.1% in patients vs. 15.7% in controls, p<0.001, relative risk (RR)=2.43) and the HLA-DRB1*07 allele (47.6% vs. 10.8%, p<0.001, RR = 4.42) were significantly associated with aortoarteritis. Furthermore, there was no significant difference in the frequency of the DRB1*0405 subtype between the patient and control groups. Thus the susceptibility to aortoarteritis in this Chinese Han population was closely related with the HLA-DRB1*04 and DRB1*07 alleles. Thus individuals with the HLA-DRB1*04 and DRB1*07 alleles may be at higher risk for developing aortoarteritis.     

Susceptibility to type 1 autoimmune hepatitis is associated with shared amino acid sequences at positions 70-74 of the HLA-DRB1 molecule

BACKGROUND/AIMS: The risk of developing autoimmune hepatitis (AIH) has been suggested to be associated with the presence of HLA-DRB1 alleles encoding the 'shared epitope' at amino acid positions 67-72 in the third hypervariable region (HVR3) of DRbeta. We aimed to identify the specific HLA alleles that are susceptible to type 1 AIH in Koreans, and to validate the shared epitope hypothesis in this single ethnic group. METHODS: Sixty-two adult patients with definite type 1 AIH and 154 healthy controls were enrolled. Alleles of HLA class I and II genes were genotyped using sequence-based typing. RESULTS: By high-resolution analysis, the frequencies of DRB1 *0405 and DQB1 *0401 were significantly increased in patients with AIH (P = 0.0001, OR = 3.74; P = 0.00006, OR = 3.95, respectively). The six amino acid motif represented by the single letter code LLEQRR or LLEQKR at positions 67-72 of the DRbeta polypeptide was not sufficient to show an increased risk for the disease. Interestingly, the QRRAA motif at positions 70-74 was significantly increased in Korean patients (P=0.04, OR=1.84). CONCLUSIONS: The shared epitope hypothesis may be extended to the amino acid motif at positions 70-74 of HLA-DRbeta in order to better predict the susceptibility to type 1 AIH.     

HLA class II distribution in Congolese with hyperthyroidism: preliminary results

OBJECTIVE: Incidence of the hyperthyroidism is continuously increasing, whereas our knowledge concerning the facilitating or etiologic factors of this increase are still partial. To evaluate some of these unknown factors, we started this preliminary study, in order to identify HLA genes in hyperthyroid Congolese, and to determine their susceptibilty in the appearance and development of hyperthyroidism at the Hospital Clinic of Kinshasa. MATERIALS AND METHODS: Nine Congolese women with hyperthyroidism, and thirteen healthy controls (3 women and 10 men) were examined and compared for HLA-DR and HLA-DQ genes analyses, from August 2000 to August 2002. DRB1 and DQB1 alleles were identified, using the Polymerase Chain Reaction (PCR) and immobilized sequence-specific oligonucleotide (SSO HLA-DRB1 and DQB1 test) probes assays. RESULTS: In the group with hyperthyroidism, three alleles (HLA-DR1, HLA-DR2, HLA-DR3) and an allele group (HLA-DR11,13,14) were found for DRB1 locus, while only one allele (HLA-DQB1*0602) was identified for DQB1 locus; allele group HLA-DR11,13,14 was the most frequent (allele frequency=0.50), followed by HLA-DR3 allele (allele frequency=0.222); 6 haplotypes were observed, with predominance of haplotype DR3/DR11,13,14 (genotype frequency=0.333), followed by haplotype DR11,13,14/DR11,13,14-DQB1*0602 (genotype frequency=0.222). In the group of healthy controls, three alleles (HLA-DR2, HLA-DR3, HLA-DR4) and an allele group (HLA-DR11,13,14) were identified for DRB1; HLA-DR2 allele was predominant (allele frequency=0.615), followed by allele group HLA-DR11,13,14 (allele frequency=0.231); a statistic significant difference was observed between the frequencies of DR2 allele and allele group DR11,13,14 in the healthy controls compared to those of hyperthyroid patients (p=0.02); 6 haplotypes were also detected in this group, the most frequent haplotype being HLA-DR2/DR2-DQB1*0602 (genotype frequency=0.540 versus 0.333 in the hyperthyroid group) (p=0.048). HLA-DQB1*0602 was dominant in the healthy controls group (allele frequency=0.890), versus HLA-DQB1*0302 (allele frequency=0.110). CONCLUSIONS: HLA-DR2, HLA-DQB1*0602 and DR2/DR2-DQB1*0.602 would play a protective role against the hyperthyroidism, while DR3 allele, allele group DR11,13,14 and haplotype HLA-DR3/DR11,13,14 would predispose to this disease or to Graves' exophtalmopathy. A large and profound study is needed to confirm our preliminary results.     

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.