In general, activated CD8+ (cytotoxic) T lymphocytes and CD4+ (helper) T lymphocytes stimulate the recruitment of cytokines and other immune mediators including interferon-γ (IFN-γ) and tumor necrosis factor-α (TNF-α) which induce basal keratinocyte apoptosis.1, , –4 This autoimmune response is thought to be triggered by various environmental factors, including vaccines, infections, medications, dental materials, tobacco use, and stress.1, , , , , –7. The gene discussed is TNF; the disease is infection.