Association between HLA‐B*58:01 allele and severe cutaneous adverse reactions with allopurinol in Han Chinese in Hong Kong

Summary Background  Allopurinol has been reported as a common cause of severe cutaneous adverse reactions (SCARs). Recent studies in various populations suggest that HLA‐B*58:01 is a strong genetic marker for allopurinol‐induced SCAR, especially in populations with a high frequency of HLA‐B*58:01 . Objectives  To confirm the association link between HLA‐B*58:01 and hypersensitivity reactions attributed to allopurinol use in Han Chinese patients in Hong Kong. Methods  We performed a case–control study to investigate whether the HLA‐B*58:01 allele predisposes to allopurinol‐induced SCAR in Han Chinese patients in Hong Kong. The HLA‐B*58:01 genotyping was performed in 20 patients with allopurinol‐induced SCAR or erythema multiforme major (EMM; n  =   1) and in 30 patients tolerant to allopurinol. Results  All of the 19 patients with allopurinol‐induced SCAR examined but not the patient with EMM carried HLA‐B*58:01 whereas only four (13%) of the control patients had this allele. The positive rate of the HLA‐B*58:01 was significantly higher in the cases than in the allopurinol‐tolerant control group [odds ratio (OR) 123·5, 95% confidence interval (CI) 12·8–1195·1; P  < 1 × 10 −4 ] and was even higher after removal of the patient with EMM (OR 229·7, 95% CI 11·7–4520·4). The sensitivity and specificity of the HLA‐B*58:01 allele for prediction of allopurinol‐induced SCAR were 100% and 86·7%, respectively. Conclusions  This study confirmed the strong association between the HLA‐B*58:01 and allopurinol‐induced SCAR in Hong Kong Han Chinese patients. A screening test for the HLA‐B*58:01 allele should effectively reduce the risk for allopurinol‐induced SCAR in Chinese populations.