HLA-DRB1 and toxic epidermal necrolysis: Furthermore, other HLA alleles which are associated with allopurinol-induced SJS/TEN such as HLA-A*33:03 (IMGT/HLA ID: HLA00106), HLA-C*03:02 (IMGT/HLA ID: HLA00410), and HLA-DRB1*15:02 (IMGT/HLA ID: HLA00867) alleles were found to have higher frequency in Thai population than others.