[Interferon and diseases].

Interferon (IFN) is part of the body's natural defense system. IFN production is a cellular response to the foreign constituents of microbes, tumors and antigens. The three types (alpha, beta and gamma) of IFN proteins differ both structurally and antigenically and have molecular weights ranging from 16,000-25,000 daltons. The IFN proteins induce antiviral, antimicrobial, antitumor, and immunomodulatory actions. We reviewed the recent studies on the relation between IFN and diseases concerning; 1) the IFN-alpha and -gamma producing capacity in patients with cancers, liver cirrhosis, diabetes mellitus and rheumatoid arthritis, 2) endogenous IFN in sera and exudates or extracts of local lesions obtained from patients with immunological diseases such as SLE, sarcoidosis, rheumatoid arthritis, Behçet's disease, and psoriasis, 3) deletion of IFN-alpha and -beta genes in human lymphoblastoid cells lines and leukemia, and 4) the expression of IFN and other cytokine (interleukins and TNF) mRNA in normal organs under physiological conditions. Although IFNs may play an important role in cancers and immunological diseases, it is necessary to consider the interactions between IFNs and other cytokines as IFN is one of the factors involved in the cytokine network in vivo.