Longitudinal Change of Varicella‐Zoster Virus‐Specific Cell‐Mediated Immunity in Hunt Syndrome and Bell's Palsy

Abstract

Objectives: (1) Compare longitudinal changes of Varicella-zoster virus (VZV)-specific cell-mediated immunity (CMI) in Hunt syndrome with Bell’s palsy using IFN-γ enzyme-linked immunospot (ELISPOT). (2) Examine the role of VZV-specific CMI for VZV reactivation in the facial nerve in Hunt syndrome. Methods: This prospective study was conducted in our tertiary referral hospital between 2010 and 2013. Nineteen Hunt syndrome and 59 Bell’s palsy patients were enrolled. Mononuclear cells isolated from whole blood were incubated with VZV antigen in culture plates for 40 hours. Anti IFN-γ antibody was added and the ELISPOT system counted immunostained spots indicating VZV-specific CMI. The relationship between the spots and days from the onset of palsy were compared between Hunt syndrome and Bell’s palsy patients. Results: Immediately after the onset, the number of spots in the Hunt syndrome group was much lower than in the Bell’s palsy group, indicating low VZV-specific CMI. However, it increased rapidly and showed a strong positive relationship between the number of spots and days from the onset of palsy ( r = 0.64) in Hunt syndrome. Several months after the onset, the number of spots in Hunt syndrome decreased gradually. In contrast, the Bell’s palsy group showed no such relationship ( r = –0.22). Conclusions: These results suggest that low CMI to VZV may play an important role in VZV reactivation in the facial nerve, thus leading to facial palsy in Hunt syndrome. VZV vaccination is considered to be a candidate to promote VZV-specific CMI for the prevention of Hunt syndrome.