The autoimmune nature of narcolepsy confirmed
Swiss researchers have identified the mechanism for the autoimmune basis of narcolepsy, thus demonstrating the relevance of a treatment against autoimmune diseases for this disorder. Their work is published in the Journal of Clinical Investigation.
Narcolepsy is characterized by including daytime sleepiness and attacks of cataplexy (muscle paralysis) due to emotions.
It has been known since the 1980s that narcolepsy is an autoimmune disease associated with an immune system gene, which is also involved in multiple sclerosis, 20% of the general population carries this gene without necessarily being sick.
For 10 years, we know that people with this disease lose neurons (nerve cells) that produce a neurotransmitter of arousal, hypocretin (also known under the name of orexin). The cause of death remained unknown, no reaction of the immune system have been identified.
“Since 2003, Professor Tafti recommended a treatment with immunoglobulins, parade of choice against other autoimmune diseases of the nervous system. With” extraordinary results “because the people treated soon after symptoms have sometimes found a normal levels of hypocretin or at least have seen most of them disappear seizures. He had to find evidence of autoimmune attack against the brain, a reaction more difficult to detect it occurs only once during the first attack, destroying at once the hypocretin neurons, instead of showing a recurring basis as in other autoimmune diseases like progressive. ”
Mehdi Tafti Researchers from the University of Lausanne and Michel Muhlethaler of the University of Geneva (Switzerland), in collaboration with European colleagues, have focused their research on hypocretin neurons, assuming that they probably produce a perceived element incorrectly by the immune system as foreign.
“A transgenic mouse has allowed the team to identify all the genes expressed by these neurons, and highlight the fact that some are more specifically expressed in these neurons compared to the rest of the brain. In particular, a gene for production of a protein, Trib2, which was recently implicated in another autoimmune disease, has been found. An analysis of the serum of 120 patients with narcolepsy in Europe – compared to other tests conducted with healthy people, who multiple sclerosis, another disease of sleep and other inflammatory neurological diseases – then revealed antibodies in people with narcolepsy Trib2 with a very high rate when the diagnosis of narcolepsy was early (in the months following the first symptoms). ”
“The evidence is such that a treatment against autoimmune diseases is appropriate when one can detect these antibodies in a person. It is then possible to avoid the destruction of hypocretin neurons carry the antigen Trib2. “