Varicella-Zoster Virus in Cerebrospinal Fluid at Relapses of Multiple Sclerosis is Infective in Vitro.

ABSTRACT

BACKGROUND: We have reported the presence of varicella-zoster virus (VZV) DNA and viral particles in the cerebrospinal fluid (CSF) of multiple sclerosis (MS) patients during exacerbation. It is not known whether these viruses are infective. AIM: To determine whether the VZV found in CSF of MS patients in exacerbation phase are infective. METHODS: VZV found in CSF of MS patients was quantified by qPCR. Vero E6 cell cultures were incubated with CSF of five MS cases positive for VZV DNA, containing herpes-like viral particles. Propagated virus harvested from these cultures were used to infect new VeroE6 cells. Localization of an immediate-early and a late structural VZV proteins was monitored by confocal microscopy after 72 h. CSF from five non-inflammatory neurological (NIN) patients were used as controls. RESULTS: A cytopathic effect was found in cultured cells inoculated with CSF from MS patients. Both, structural VZV glycoprotein (gB) and immediate-early VZV protein (IE62) were detected in Vero E6 cultures inoculated with samples from all five MS cases. CSF from control patients produced no effect on Vero E6 cells. CONCLUSION: When present in the CSF at relapses of MS, VZV is infective under in vitro conditions.