Revisiting HLA-DQA1 *05 in Asian inflammatory bowel disease cohorts: Ethnic variations in genetic susceptibility to immunogenicity

We read with great interest the article by Weng et al , wherein the authors investigated human leukocyte antigen (HLA) alleles linked to anti-drug antibody (ADA) formation in Taiwanese patients with inflammatory bowel disease. They reported that HLA-DQA1 *05, a major risk allele in European cohorts, demonstrated no association with ADA development in Taiwanese patients. Instead, novel alleles emerge: HLA-C *03:04:01 correlating strongly with anti-infliximab ADAs and HLA-B *15:18:01 with anti-adalimumab ADAs. However, this finding contrasts with evidence from large cohort studies, wherein HLA-DQA1 *05 consistently predicted ADA formation, particularly for infliximab. This letter aimed to contextualize these findings within the broader literature and to lay the ground for further analysis of ethnic variations and the implications for personalized medicine in inflammatory bowel disease. This divergence may suggest how genetic architecture shapes immunogenicity risk across ethnicities.