TCR sequencing analysis have identified specific TCR clonotypes preferentially expressed in blister fluid and blood of carbamazepine-induced SJS/TEN patients.8 Functionally, T cells carrying these TCR clonotypes triggered a carbamazepine specific immune response both in vitro and in HLA-B*15:02 transgenic mice.8,9 A study using HLA-B*57:01 transgenic mice indicated that deficiency of CD4+ T cells in vivo induced an abacavir hypersensitivity syndrome like phenotype. This evidence concerns the gene HLA-B and toxic epidermal necrolysis.