Multiple sclerosis (MS) is a chronic and often disabling neurodegenerative disease of the central nervous system. It is still a pathology with many uncertainties, for example, it is difficult to predict at the time of diagnosis how and how quickly it will affect the patient. This makes it difficult to prescribe specific treatments. Among the factors that can influence the evolution of the disease are other viruses. A Vall d'Hebron study published in the Journal of Neurology, Neurosurgery and Psychiatry has found that having a strong immune response to cytomegalovirus at the time of the first outbreak translates into a better prognosis of the disease at almost all levels. The research has been led by Dr. Manuel Comabella, from the Clinical Neuroimmunology Service of Vall d'Hebron University Hospital, principal investigator of the Clinical Neuroimmunology group of Vall d'Hebron Research Institute (VHIR) and head of laboratory of the Multiple Sclerosis Center of Catalonia (Cemcat).

One of the new aspects of the study is that it carried out a 20-year monitoring, one of the longest follow-ups ever carried out for this type of pathology. This has made it possible to discover trends that remain hidden in shorter periods. The most significant data that has come to light is that patients who, at the time of diagnosis, had a high level of antibodies against the cytomegalovirus virus had, on average, a better evolution of the pathology. This better progress could be measured by the delay in reaching milestones in the progression of the disease. In general, the time that patients spent before needing medication, moving up the dependency scale and, if they had the relapsing-remitting variant of the disease, they had permanent sequels, was prolonged.

Scientists do not know the mechanism which links antibodies against cytomelagovirus with a better prognosis in MS, but it is clear that there is a correlation. This virus of the herpes family has a prevalence in Europe of 60% of the population, rising to almost 100% in developing countries. Once acquired, it is very difficult to eliminate, instead it is usually kept in hibernation, reactivating during periods when the patient is immunosuppressed. Its prevalence means that it is very likely that patients newly diagnosed with Multiple Sclerosis have had some contact with it and therefore physicians can test their immune response. Using these antibodies as a biomarker may help to clear some of the great doubts that have to patients when they are diagnosed with MS. This may open the door to more personalized treatments.

The researchers also analyzed the role played by another virus of the herpes family, the so-called Epstein-Barr virus, in MS. Several studies have identified this virus as a necessary condition for developing the pathology. Although the study confirmed that all the analyzed persons diagnosed with MS have or have had this virus, the level of immune response to Epstein-Barr or its prevalence had little relevance in the evolution of the disease.