对中国人群正常人及类风湿关节炎病人ＤＲ＿４亚型基因决定型别特异性的第二个外显子进行体外扩增、克隆及序列分析显示，６例正常人及３例类风湿关节炎病人存在三种ＤＲ＿４亚型（ＤＲＢｌ０４０２，ＤＲＢｌ０４０５，ＤＲＢｌ．０４０６），中国人这三种亚型第二个外显子核苷酸序列与白种人一致。序列分析结果为进一步应用常规ＰＣＲ－ＳＳＯ法及ＰＣＲ－ＲＦＬＰ法进行中国人ＤＲ＿４基因定型提供了依据。此外，还将序列分析结果与ＰＣＲ－ＳＳＯ杂交分析结果进行了比较，具备较全面的覆盖各亚型多态性区域的探针可以减少等位基因同源性干扰，减少分型误差 The second exon of type-specific DR_4 subtype genotypes was amplified in vitro from normal and rheumatoid arthritis patients in China. Clone and sequence analysis showed that 6 normal subjects and 3 rheumatoid arthritis patients There are three DR_4 subtypes (DRB10402, DRB10405, DRB10.0406). The second exon nucleotide sequence of these three isoforms in Chinese is consistent with that of Caucasians. Sequence analysis provided the basis for further application of conventional PCR-SSO and PCR-RFLP methods for Chinese DR_4 gene typing. In addition, the sequence analysis results were also compared with the results of PCR-SSO hybridization analysis. A comprehensive probe covering the polymorphic regions of each subtype could reduce allele homology interference and reduce the typing error