Both HLA-DQB1*03:01 and HLA-DQA1*05:05 were significantly associated with elevated anti-drug antibody levels (p = 3.23E-03 and 3.54E-03, respectively).<h4>Conclusions</h4>HLA-DQB1*03:01 encompasses the information of HLA-DQA1*05:05 and serves as a strong genetic predictor of IFX treatment persistence and immunogenicity in Japanese patients with IBD, offering a potential biomarker for personalized therapy. The gene discussed is HLA-DQA1; the disease is inflammatory bowel disease.