The role of the Epstein-Barr virus receptor CD21 in multiple sclerosis.

Multiple Sclerosis (MS) is characterised by a chronic inflammation and demyelination of brain and spinal cord with a yet unknown aetiology. Based on multiple epidemiological and immunological studies, which suggest a role of Epstein–Barr virus (EBV) infection in the pathogenesis of MS, we investigated CD21 (CR2, complement receptor type 2), which serves as the EBV receptor. Serum concentrations of soluble CD21 receptor (sCD21) were determined in MS patients and controls. In accordance with findings in other autoimmune disorders decreased sCD21 levels were found in MS patients. On ß-IFN treatment serum sCD21 concentrations further decreased. To explore the role of the CD21 gene for MS susceptibility and the altered CD21 levels in MS patients we performed exon sequencing of the CD21 gene. While we identified new single nucleotide polymorphism (SNP) and confirmed previously reported SNPs, none of the SNPs was associated with MS. Our findings demonstrate that sCD21 expression is altered in MS patients similar to other autoimmune diseases although no evidence was found for a specific role of the CD21 gene in MS.