Interferon system in patients with rheumatoid arthritis and sclerodermia systematica.

In the blood of patients with rheumatoid arthritis and/or sclerodermia systematica usually acid-labile interferon-alpha (IFN-alpha) was found. Blood leukocytes cannot be considered the source of its production as they spontaneously produce IFN-gamma identified with specific antiserum. Blood leukocytes of tested patients generated in vitro a reduced amount of staphylococcus enterotoxin A-induced IFN-gamma and virus-induced acid-labile IFN-alpha. This findings support the assumption of impaired functioning of T- and B-blood cells in autoimmune diseases. The production of Newcastle diseases virus-induced IFN-alpha and influenza virus-induced acid-stable IFN-alpha by patients' leukocytes has not been altered. Acid-labile IFN-alpha obtained from the blood of tested patients, IFN-gamma spontaneously generated by leukocytes in vitro and acid-labile IFN-alpha produced by leukocytes in vitro following induction with influenza virus show similar sensitivity to pH 2.0 and time patterns of the antiviral state development in human diploid fibroblast culture.