[Interferon alpha (IFNalpha) treatment for Sjögren's syndrome].

IFNalpha is important for the defense against viral infection. By using a sensitive radioimmunoassay, we previously established the existence of endogenous IFNalpha in human. Serum IFNalpha, i.e., endogenous IFNalpha gradually increases with age, reaching the highest peak at young adults and then gradually declining with aging. We also found that serum IFNalpha levels were significantly low in the patients with Sjögren's syndrome. Subsequent treatment with a small dose 450 IU/day of orally administered IFNalpha significantly improved saliva secretion and the pathology of salivary glands of the patients as well. Since natural killer (NK) cell activity has been reported to be significantly decreased in the patients likely because of the decrease of IFNalpha, we may assume that correction of endogenous levels of IFNalpha by administering small amounts of IFNalpha will improve the vicious cycle in the pathology of the patients with Sjögren's syndrome.