A study by the University of Copenhagen and the Technical University of Denmark, published in the scientific journal Nature has confirmed that narcolepsy has an autoimmune origin, as already discovered last September by an important Swiss study, conducted, among others, by the Institute for Research in Biomedicine (Bellinzona), the Neurocenter of Southern Switzerland (Lugano), ETH Zurich and the Inselspital of Bern. This study also appeared in Nature.
What did the Danish researchers discover and confirm? Narcolepsy – as we know – is a chronic neurological disorder that, among its other symptoms, causes excessive day-time sleepiness with sufferers feeling suddenly drowsy and not being able to fight the urge to sleep. For a long time scientists had discussed the origins of this disorder, focusing particular attention on a possible neurological origin (hence believing it derived from defects in a certain area of the brain).
Recently, however, the researchers managed to identify several kinds of T lymphocytes (fundamental cells of the immune system) that mistakenly destroy the cells of the hypothalamus (a region of the brain) that produces hypocretin, i.e. the protein that regulates the sleep-wake cycle and also several kinds of emotional behavior. It is the absence of hypocretin that then causes narcolepsy. Therefore, the “blame” for this disease is to be attributed to defects in the immune system, and not to those in the nervous system.
With regard, in particular, to the study conducted by the University of Copenhagen and the Technical University of Denmark, the researchers analyzed the blood of 20 patients and 52 healthy volunteers, and discovered that only the former had high levels of a sub-group of T lymphocytes, called CD8, considered jointly responsible, together with other lymphocytes (CD4 already identified by the Swiss researchers) for the outbreak of autoimmune reactions.
This discovery is important because, at this point, it will finally be possible to study therapies “targeted” at this disorder, and to search for a series of signals in the blood of patients that will allow us to understand at the earliest opportunity if the illness is about to strike.