Predominant frequency of HLA-B*27 in patients with ankylosing spondylitis in southeastern China.

Objectives: This study was to investigate the polymorphism and distribution of alleles of HLA-B*27 in patients with ankylosing spondylitis (AS) in Han population of southeastern China.

Methods: A total of 89 peripheral blood samples from southeastern Chinese Han patients with AS that diagnosed according to Modified New York criteria were subtyped using the high-resolution PCR-SSP.Exon 2-3 of HLA-B*27 gene was amplified and sequenced to further confirm the HLA-B*27 subtype.

Results: The frequency of HLA-B*27 was 99.87% in AS patients. Three subtypes, HLA-B*2704, HLA-B*2705, and HLA-B*2706 were identified. The frequencies for these three alleles were HLA-B*2704 in 84/88 (95.46%), HLA-B*2705 in 3/88(3.41%), and HLA-B*2706 in 1/88 (1.13%) of the HLA-B*27 positive patients, respectively.

Conclusions: Our study shows that HLA-B*2704 has an overwhelming frequency in southeastern Chinese Han AS patients. A combined analysis including previous studies of HLA-B*27-subtype distributions in Chinese Han populations showed that HLA-B*2704 may originate from the southern Han and then migrate and spread to the northern areas, and HLA-B*2705 show the opposite result.