Association of HLA-B27 with ankylosing spondylitis and clinical features of the HLA-B27-associated ankylosing spondylitis: a meta-analysis

Many studies have estimated the correlation between HLA-B27 polymorphisms and ankylosing spondylitis (AS). However, the results were controversial. Therefore, we performed this meta-analysis to determine the association of HLA-B*27 polymorphisms with AS and investigate the impacts of HLA-B27 on the clinical symptoms of AS patients. A comprehensive search was performed in PubMed, Web of Science and Embase databases to retrieve the eligible studies, which addressed the association between HLA-B27 polymorphisms and AS susceptibility. The correlation in fixed-effect model was estimated using the relative risk (RR) and 95% confidence intervals (CI). Finally, 41 studies were included in this meta-analysis, among which 35 studies were used to analyze the correlation between HLA-B27 and AS. And 11 studies were applied to estimate the effects of HLA-B27 on the clinical characteristics of AS patients. Besides, our meta-analysis was composed of 8993 AS patients and 19,254 healthy controls. The results suggested that HLA-B27, HLA-B27*02 and HLA-B27*04 were positively in relation to AS (RRHLA-B27 (95% CI) 16.02 (13.85, 18.54), P < 0.001; RRHLA-B*2702 (95% CI) 1.28 (1.08, 1.53), P = 0.005; RRHLA-B27*04 (95% CI) 1.14 (1.01, 1.29), P = 0.041). Moreover, positive association was observed between HLA-B27 and sex (male) [RR (95% CI) 1.10 (1.05, 1.15), P < 0.001], family history [RR (95% CI) 1.10 (1.06, 1.140), P < 0.001], uveitis [RR (95% CI) 1.07 (1.03, 1.11), P < 0001], peripheral joint involvement [RR (95% CI) 1.04 (1.01,1.07), P = 0.013] and hip joints involvement [RR (95% CI) 1.06 (1.02, 1.10), P = 0.003]. In addition, we also found that HLA-B27*04 showed association with peripheral joint involvement [RR (95% CI) 1.13 (1.05–1.23), P = 0.002]. In conclusion, the current meta-analysis indicates that HLA-B27, especially, its subtypes (HLA-B27*02 and HLA-B27*04) may be potential risk factors for AS.