Narcolepsy is a chronic neurological disorder characterized by excessive day time sleepiness, cataplexy and hypnagogic and hypnopompic hallucination. Narcolepsy is caused by loss of hypocretine neuron. Hypocretine is an excitatory neuropeptide projecting in the central nervous system and maintains wakefulness. The mechanism of hypocretin loss in narcolepsy is elusive. However, an autoimmune mediated destruction of hypocretin neuron is suspected because of its firm association with HLA-DQB1*0602 genotype and polymorphism in the TCR-α chain. Furthermore, infection with streptococcus pyogenes, influenza A H1N1 strain and the Pandemrix vaccine itself has strong association with narcolepsy. We