Elevated serum interferon levels in patients with Bell's palsy.

Serum interferon (IFN) levels were analyzed in patients with Bell's palsy to study the immune response in the disease. Serum samples from 91 patients were assayed for antiviral activity using a bioassay. The IFN levels in the serum were elevated in the acute and convalescent phases as compared with control subjects. The serum IFN-gamma levels were analyzed by radioimmunoassay in 32 of the patients: the IFN-gamma levels were alike in the acute and convalescent phases and the control subjects. Neutralization with specific antisera against IFN-alpha, -beta, and -gamma on 15 serum samples of 11 patients with elevated IFN activity showed a complex pattern that indicates that the antiviral activity was due to a mixture of IFNs and possibly also due to other factors. The elevated IFN levels indicate a low-grade antiviral response that may reflect the reactivation of a viral infection.