Which genetic marker is associated with allopurinol-induced DRESS in Chinese patients?

• A. HLA-B*27:05
• B. HLA-B*58:01
• C. HLA-DRB1*04:01
• D. HLA-A*02:01

Answer: (B)

Genetic predisposition to severe drug hypersensitivity is driven by specific HLA alleles that shape how the immune system presents drug-related peptides to T cells. For allopurinol-induced DRESS in Chinese patients, the key marker is HLA-B58:01. People carrying this allele have a markedly higher risk of developing DRESS when exposed to allopurinol compared with those without it. The other HLA alleles listed do not show the same strong association with allopurinol-triggered DRESS in this population. This connection helps explain why genetic testing for HLA-B58:01 can be useful in assessing risk before starting allopurinol in East Asian individuals. The concept hinges on the drug or its metabolites being presented by this specific HLA molecule to T cells, leading to an immune hyperreactivity that manifests as DRESS.