As the H1N1 swine flu pandemic swept the world in 2009, China saw a spike in cases of narcolepsy — a mysterious disorder that involves sudden, uncontrollable sleepiness. Meanwhile, in Europe, around 1 in 15,000 children who were given Pandemrix — a now-defunct flu vaccine that contained fragments of the pandemic virus — also developed narcolepsy, a chronic disease.
Immunologist Elizabeth Mellins and narcolepsy researcher Emmanuel Mignot at Stanford University School of Medicine in California and their collaborators have now partly solved the mystery behind these events, while also confirming a longstanding hypothesis that narcolepsy is an autoimmune disease, in which the immune system attacks healthy cells..
It has been an interesting set of observations that have led up to this: I have chronicled some of them here in Virology News, as I picked up on how both the H1N1 2009pdm vaccine and the native virus seemed to be associated with narcolepsy.
And now the mystery is partly solved: some genetically-predisposed individuals produce CD4+ T-cells that recognise enogenous hypocretin, that are triggered by swine flu – and perhaps also by other flu virus.
That is, of course, not the whole story – but at least we are part fo the way to understanding how this puzzling and rather disturbing correlation of particular influenza viruses and narcolepsy occurs.
See on www.nature.com