CD4 and narcolepsy: Remarkably, even after the discovery of hypocretin-producing neurons as the putative autoimmune target, attempts to demonstrate narcolepsy-associated autoimmune responses have largely been unsuccessful (reviewed in ref. 15), until recently where autoreactive CD4+ T cells targeting hypocretin were detected in blood samples from narcolepsy patients16 and CD4+ T cells recognizing hypocretin were demonstrated to cross-react to the hemagglutinin protein from the 2009/2010 H1N1 influenza A virus17.