Polymorphisms of human leukocyte antigen B*27 on clinical phenotype of spondyloarthritis in Chinese.

BACKGROUND

In recent years, an ever-increasing number of alleles of human leukocyte antigen B27 (HLA-B27) have been identified. This study aimed to establish an updated method for HLA-B27 subtyping, and to investigate the impact of HLA-B27 polymorphisms on the clinical phenotype of spondyloarthritis (SpA).

METHODS

Overall, 184 SpA patients were recruited for analyzing diversity of HLA-B*27 via an updated high-resolution polymerase chain reaction amplification with sequence specific primers (PCR-SSP).

RESULTS

The prevalence of HLA-B27 was 94.0%, and four subtypes were identified including HLA-B2704 (77.5%), B2705 (20.2%), B2707 (1.7%), and B2724 (0.6%). There was an obvious male predominance (P=.05) and markedly elevated C-reaction protein (CRP) in B27 positive SpA (P<.01). In multivariate linear regression analysis, the elevated CRP was positively associated with HLA-B27 positivity (regression coefficient B=46.1, P=.0003), grade of sacroiliitis (B=47.5, P=.0032), and male gender (B=20.4, P=.0041). Notably, a male predilection was also found in B2705 positive SpA while B*2707 was associated with older age, higher positive family history, and higher prevalence of extra-articular features (all P<.05).

CONCLUSIONS

In this study, an updated PCR-SSP technique to identify increasing alleles of HLA-B27 was developed and their different effects on clinical manifestations of SpA were demonstrated. Genotyping of HLA-B27 would shed light on our understanding of the pathogenesis of SpA.