Role of T-lymphocyte subsets in facial nerve paralysis owing to the reactivation of herpes simplex virus type 1

Conclusion. Although both T-cell subsets are essential for inhibiting HSV-1 reactivation in the GG, CD4+ T cells play a more important role in host defense against virus replication. Objective. To elucidate the host immunological factors that participate in herpes simplex virus type 1 (HSV-1) reactivation in the geniculate ganglia ( GG) and lead to facial paralysis, we developed a mouse model of facial paralysis that involved the reactivation of HSV-1 following general immune suppression. Material and methods. Eight weeks after recovery from primary facial paralysis caused by inoculating the auricle with HSV-1 the auricle was scratched and mice (n = 69) were given an i.p. injection of either anti-CD4 (n = 46) or anti-CD8 (n = 23) monoclonal antibody to deplete specific T-lymphocyte subsets. Following this reactivation procedure, the rate of recurrent facial paralysis was compared between the two models. The GG were examined histopathologically and using polymerase chain reaction to detect HSV-1 DNA. Results. Facial paralysis developed in 42% of mice in the anti-CD4 model and in 13% in the anti-CD8 model. HSV-1 DNA was detected in 50% of the mice in both models. Histopathologically, neurons were destroyed in parts of the GG and numerous virus particles were seen in the surviving neurons.