Objectives: A study was performed to determine whether persistent or latent viruses are reactivated during the acute attack in relapsing remitting multiple sclerosis (MS).
Material and methods: DNA of herpes simplex virus type 1 and 2 (HSV-1 and -2), human cytomegalovirus (HCMV), Epstein-Barr virus (EBV), JC virus (JCV) and HTLV-I was searched, using nested polymerase chain reaction (PCR), in peripheral blood mononuclear cells (PBMCs) collected from 14 MS patients on the first day and, twice a week, during an acute attack of the disease.
Results: Viral DNA was detected, in at least one PBMC sample, in all the patients. Interestingly, EBV DNA was found in 42.8% of the patients on the first day, while a sharp increase of the HTLV tax-rex DNA frequency (35.7%) was observed on the tenth day.
Conclusions: In MS relapse EBV DNA detection is an early, frequent event, while the finding of tax-rex, but not of other HTLV-I genomic regions, is a secondary phenomenon, suggesting that these two factors could interact in the pathogenesis of MS relapses.