In vitro Effect of EBV Infection on HERV-K18 env Expression in the Presence and Absence of Vitamin D in Multiple Sclerosis Patients

HERV-K env is associated with several neurological disorders, including MS. Clinical studies have demonstrated a plausible interaction between HERV-K env and other MS risk factors. The present study aimed to investigate the possible association between HERV-K18 env and TGF-β. We further assessed the in vitro effect of EBV infection on HERV-K18 env expression in the presence and absence of vitamin D in MS patients.

PBMCs from 20 MS patients and 20 healthy controls were infected with the B95.8 EBV, seeded into 24-well plates and incubated in the presence or absence of 100 nM of 1,25(OH)D3. The expression levels of HERV-K18 env and TGF-β were measured using real-time PCR.

While the expression level of HERV-K18 env was significantly higher in MS patients than the healthy controls, this trend for TGF-β was significantly reverse. Interestingly, an inverse correlation was found between HERV-K18 env and TGF-β expression in MS patients, although the in vitro stimulation of PBMCs with EBV and vitamin D showed no significant differences in terms of HERV-K18 expression.

Our findings highlight the potential role of HERV-K18 env in MS patients.