HLA-B60 and B61 are strongly associated with ankylosing spondylitis in HLA-B27-negative Taiwan Chinese patients

Objectives. Carriage of HLA-B60 has been shown to increase the risk of ankylosing spondylitis (AS) in B27-positive Caucasian patients, but the association in B27-negative cases is less certain. This study assessed HLA class I gene associations in Chinese HLA-B27-negative AS patients. Methods. Forty-one Chinese HLA-B27-negative AS patients fulfilling the modified New York diagnostic criteria for AS were recruited, and 11383 HLA-B27-negative blood donors were used for comparison. HLA-A and -B typing was done with the microlymphocytotoxicity assay. Results. Among the B27-negative AS patients, 21 were male and 20 were female. Of HLA-B alleles, only B60 and B61 significantly increased susceptibility to AS in HLA-B27-negative patients (P<0.001). Conclusions. In Taiwan Chinese, carriage of B60 is increased in HLA-B27-negative AS patients. The association between B61 and HLA-B27-negative AS patients has not been reported previously. Whether the gene involved is HLA-B60 or B61 or another gene in linkage disequilibrium with these genes is unknown.