CD8A and Stevens-Johnson syndrome: As the CD8+ T cell cytolytic program can have both positive and negative consequences for the host (14–33), understanding the mechanisms that drive cytotoxic CD8+ T cell programs remains an important goal for unraveling the pathogenesis of numerous diseases such as alopecia, vitiligo, bullous pemphigoid, Stevens-Johnson syndrome, and toxic epidermal necrolysis, in which cytolytic CD8+ T cells contribute to pathogenesis (15, 32, 34–37).