Varicella-zoster virus-specific cell-mediated immunity in Ramsay Hunt syndrome.

OBJECTIVES/HYPOTHESIS The etiology of Ramsay Hunt syndrome (Hunt syndrome) is reactivation of latent varicella-zoster virus (VZV) in the geniculate ganglion of the facial nerve, leading to neuritis. Although the mechanism of the VZV reactivation is unclear, one possibility is that the reactivation involves a low level of VZV-specific cell-mediated immunity (CMI). The aim of this study was to clarify the characteristics of the VZV-specific CMI in Hunt syndrome compared to that in Bell's palsy, and to obtain clues to its role in the development of Hunt syndrome. STUDY DESIGN Prospective study. METHODS We determined the median spot numbers and examined VZV-specific CMI in patients with Hunt syndrome and with Bell's palsy using interferon-γ enzyme-linked immunospot (ELISPOT) assays. We analyzed the relationship between the value of VZV-specific CMI and days from disease onset. RESULTS The median spot number in Hunt syndrome (87.3 spot-forming cells [SFCs]/4 × 10(5) peripheral blood mononuclear cells [PBMCs]) was higher than that in Bell's palsy (62.3 SFCs/4 × 10(5) PBMCs). Hunt syndrome showed a strong relationship between the ELISPOT count and days from onset (r = 0.65). Within the first 5 days from onset, no ELISPOT counts higher than 80 SFCs/4 × 10(5) PBMCs were observed. On the other hand, no correlation was observed between the ELISPOT count and days from onset in patients with Bell's palsy (r = -0.19). CONCLUSIONS These results suggest that VZV-specific CMI in Hunt syndrome is low at disease onset and increases rapidly thereafter. Consequently, reduced VZV-specific CMI may play an important role in the reactivation of VZV in the facial nerve, leading to Hunt syndrome.