A patient with both narcolepsy and multiple sclerosis in association with Pandemrix vaccination.

Narcolepsy with cataplexy is caused by a selective loss of hypocretin-producing neurons, but symptomatic narcolepsy can also result from hypothalamic and brainstem lesions caused by multiple sclerosis (MS). We report a previously healthy man who developed clinical and laboratory verified narcolepsy without having any indication of hypothalamic lesions and MS after vaccination against the influenza H1N1 with Pandemrix. HLA typing showed both DRB1*15:01, associated with MS and DQB1*06:02, associated with narcolepsy. The genetic susceptibility in this patient makes it tempting to speculate upon an immune-mediated mechanism and a common etiology for both diseases in this patient.