Comparison of HLA-B*27 subtypes between Chinese patients with ankylosing spondylitis and non-ankylosing spondylitis carriers

OBJECTIVE: To investigate the distribution of subtypes between HLA-B*27 (+) patients with ankylosing spondylitis (AS) and carriers. METHODS: This case–control study recruited Chinese Han patients with HLA-B*27 (+) AS from six hospitals in Zhejiang Province, China between 2013 and 2018. Patients who were examined for HLA-B*27 because of back pain or arthralgia but who did not have AS or arthritis were recruited as controls. HLA-B*27 target DNA was amplified by amplification refractory mutation systems and HLA-B*27 subtypes were determined by sequencing. RESULTS: The positive rate of HLA-B*27 was significantly higher in the AS group than in the control group. In AS patients, HLA-B*2704 was predominant at 86.4%, followed by HLA-B*2705 at 12.6%; HLA-B*2704 and HLA-B*2705 were found in 70.0% and 10.0% of controls, respectively. HLA-B*2702 and HLA-B*2706 were detected at low frequencies in the control group, while the rare subtype HLA-B*2715 was only observed in two (1.0%) patients with AS. HLA-B*2707 was not detected in AS or control groups. CONCLUSION: HLA-B*2704 is the predominant subtype among patients with AS and carriers in southeast China.