Notably, deep sequencing of the TCR CDR3 repertoire revealed that there was a massive expansion of unique CD8+ T cell clones in patients with TEN (both in skin and blood), which express an effector memory phenotype and an elevated level of cytotoxic or inflammatory/activation markers such as granulysin, granzymes A and B, or CD38. This evidence concerns the gene CD8A and toxic epidermal necrolysis.