IMPAIRED INTERFERON-PRODUCTION BY LEUKOCYTES FROM PATIENTS WITH BELL PALSY AND LACK OF FINDINGS SUGGESTIVE FOR A SYSTEMIC VIRAL INVOLVEMENT

Hypothesis: This study aimed to test the hypothesis that viral and oth er microbial infections cause Bell palsy and to use the interferon (IF N) alpha/beta-induced MxA protein as an indicator of systemic viral in fection. Background: Bell palsy has been previously associated with se veral viral infections. Recently, after this study was completed, herp es simplex virus DNA was detected in the endoneurial fluid of some pat ients with Bell palsy. Methods: Serum and blood mononuclear cells were obtained from 30 patients with Bell palsy and 12 control subjects. Th e sera were tested for antibodies to 21 microbes. Mononuclear cells we re assayed for (a) MxA protein using immunoblotting and (b) capacity t o produce IFN in short-term culture after stimulation with influenza A virus. Results: No significant differences were seen in serum antibod ies or MxA protein between the patients and controls. The geometric me an of leukocyte IFN production in the convalescent phase of Bell palsy patients was higher than in the acute phase but remained still at sig nificantly lower levels as compared with the control group (p < 0.05). In three patients there was no detectable IFN production. Conclusions : These results provide no evidence for a systemic viral involvement i n Bell palsy, but the observed decreased IFN-producing capacity at the onset of Bell palsy could be a sign of transient immunosuppression or of an abnormal frequency of leukocyte subpopulations in the disease.