Neutralization antibody to herpes simplex virus type 1 in Bell's palsy

In 45 patients with Bell's palsy of recent onset, the neutralization antibody titers to herpes simplex virus type 1 (HSV-1) were assayed by a microtiter technique. As a control, the neutralization antibody titers of 50 normal subject were assayed. Complement fixation tests also were performed. The geometric means of the neutralization antibody titers of the patients appeared higher at all times than those of the normal subjects. Significant change in the neutralization antibody titer suggesting a recent infection of HSV-1 was seen in seven patients (15.6%), while the complement fixation test demonstrated significant change in only one patient (2.2%). The higher geometric means of the neutralization antibody titers in the patients was thought to indicate that reactivation of the HSV-1 infection was responsible for the onset of Bell's palsy.