Immunopathologic investigations have shown the presence of cytotoxic cells, including CD8 + cytotoxic T lymphocytes (CTLs), natural killer T cells (NKT), and macrophages in early skin lesions of SJS/TEN, suggesting that cell-mediated cytotoxic reactions contribute to extensive keratinocyte apoptosis32,33. This evidence concerns the gene CD8A and toxic epidermal necrolysis.