Browsing by Author "Dürnsteiner, Pia Karoliina"

Multiple sclerosis (MS) is one of the most common reasons for neurological disability in young adults, yet the aetiology of the disease remains to be discovered. MS involves an autoimmune reaction in the central nervous system, which results in demyelination, axonal degradation, and inflammation. These result in various symptoms, such as motor and sensory disturbances, cognitive symptoms, fatigue, and problems with balance. MS is chronic and progressive, and medications are used to slow the neuronal damage and reduce relapses. The most evident risk factor for MS is Epstein-Barr virus (EBV) infection, as nearly 100% of MS patients are seropositive for the virus. However, the mechanism how EBV contributes to the disease is not known. A highly sensitive quantitative multiplex PCR method was used to examine reactivation of EBV and eight other human herpesviruses in the saliva of MS patients (n=9) and healthy controls (n=7). Single-cell RNA sequencing methods were used to study the cell composition and expression patterns of cerebrospinal fluid (CSF) in treatment-naïve MS patients at the diagnostic phase (n=4) and in controls (n=4). EBV was found to be shedding in eight out of nine MS patients and in only one control, and the viral load was significantly higher in MS patients. Single-cell sequencing of the CSF revealed that MS induces expansion of antibody producing and cytotoxic cell types. Differential expression analysis found that MS CSF B cells significantly express EBNA1BP2, which plays a crucial role in the replication and partitioning of EBV episomes in infected cells. These results support the involvement of EBV in MS. Better knowledge of the viral role in the onset of MS will be useful in the development potential antiviral drugs and EBV vaccination that could even prevent the disease.