It has now been suspected for a long time, and researchers have just proven that narcolepsy is an autoimmune disease.
Narcolepsy is a chronic sleep disorder, which appears mainly in young people between 10 and 30 years old. It affects one person in 3,000 to 5,000 in France, so it is a rare disease. It causes symptoms of uncontrollable drowsiness and difficulty staying awake, it can even cause hallucinations, even if medication exists.
70% of patients also suffer from cataplexy, characterized by a sudden drop in muscle tone. It is narcolepsy type 1, the most common. It is characterized by a deficit of hypocretin, a molecule that controls wakefulness. This means that, in affected people, the neurons that produce hypocretin function less well. This new research, published in the journal NatureCommunicationsproves what many researchers have suspected for several years: the autoimmune nature of narcolepsy.
There would be a predisposition to narcolepsy
To conduct this study, Danish researchers analyzed the blood of 20 narcolepsy patients and 52 healthy people. They noticed that almost everyone with the disease had auto-reactive CD8 T cells. The role of these T lymphocyte cells is to recognize the antigens of the neurons which produce hypocretin, and to destroy the infected cells.
Birgitte Rahbek Kornum, who led this work, explains what this means: “We found self-reactive cytotoxic CD8 T cells in the blood of patients with narcolepsy. That is, the cells recognize neurons which produce the hypocretin which regulates the subject’s wakefulness. This does not prove that they are the ones which killed the neurons, but it is an important step forward.”
Two new avenues to analyze
However, self-reactive cells were also present in healthy people : “here, the cells were probably not activated”, explains the researcher. “That’s something we’re seeing more and more often with autoimmunity – that it’s dormant in all of usbut is not activated in everyone.” The next step will therefore be to discover what mechanism activates these self-reactive cells. Two tracks will be analyzed: a genetic predisposition or an infection (or both). Others Research will be needed to elucidate the question, but this discovery could make it possible to develop drugs that target the immune problem, and thus better treat narcolepsy.
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