For example, the abacavir-induced severe hypersensitivity reaction affecting multiple organs is strongly associated with the HLAB*5701 allele in whites,[45] the Stevens-Johnson syndrome after carbamazepine treatment in Han Chinese occurs in patients with the HLA-B*1502 allele,[33] and HLA-B*5801 is an important genetic risk factor for severe allopurinol-induced cutaneous adverse reactions such as Stevens-Johnson syndrome and toxic epidermal necrolysis [46]. This evidence concerns the gene HLA-B and Stevens-Johnson syndrome.