Pathogenesis of multiple sclerosis: expression of HERV-Fc1: a human endogenous retrovirus

healthy controls and from MS patients. We found higher HERV-H/F Gag expression in peripheral blood CD19+ cells and significantly higher expression in monocytes in patients with non-active MS than in healthy controls. For patients with active MS, much higher differences in the HERV-H/F Gag expression relative to healthy controls were detected for CD4+ and CD8+ T cells indicating that this HERV family may play a role in the extensive activation of the innate and adaptive immune responses in MS. Also for patients with active MS, the expression of HERV-H/F Gag by CD4+ T cells was significantly higher than that by CD8a+ T cells. Extracellular HERV-Fc1 RNAs were detected in plasma samples from both healthy controls and from MS patients. In plasma samples from patients with nonactive MS, higher levels of extracellular HERV-Fc1 RNAs were found as compared with healthy controls. Moreover, a 5-fold increase of the amount of extracellular HERV-Fc1 RNA was found in plasma samples from patients with active MS as compared with healthy controls.