Immune response to a flu protein yields new insights into narcolepsy

An international team of researchers has found some of the first solid
evidence that narcolepsy may be a so-called "hit-and-run" autoimmune
disease.

The authors propose a hit-and-run autoimmune mechanism for how both
swine flu and the vaccine Pandemrix might cause narcolepsy. They suggest that in
genetically predisposed people, high levels of the H1N1 protein
stimulate the production of large amounts of antibodies to both the
virus (or vaccine) and the hypocretin receptor. These antibodies may persist in the
blood for months. Either the large numbers of antibodies or inflammation
from an unrelated infection could alter the blood-brain barrier,
allowing the antibodies to enter the brain. There, the antibodies may
latch onto hypocretin receptors, possibly directing the immune system to
destroy or suppress brain cells critical to regulating sleep-wake
cycles.

H1N1-Flu triggered narcolepsy may stem from 'molecular mimicry'

In genetically susceptible people, narcolepsy can sometimes be triggered by a similarity between a region of a protein called hypocretin and a portion of a protein from the pandemic H1N1 virus, according to a new study by researchers at the Stanford University School of Medicine.