The onset of narcolepsy is believed to arise from the interplay of genetic and environmental factors, leading to an immune-mediated selective loss or dysfunction of orexinergic neurons.[25] Consequently, individuals with narcolepsy exhibit elevated levels of tumor necrosis factor alpha and interferon-gamma in their serum, alongside activation of CD4+ and CD8+ T cells. The gene discussed is CD8A; the disease is narcolepsy.