Abstract: Disclosed is a method of determining the presence and activity of interferon inhibitors in a test sample, preferably human blood serum. The method includes the steps of culturing cells which express an interferon-inducible antigen in the presence of an interferon and then adding an aliquot of the cultured cells to a test sample and to a control sample. The expression of the interferon-inducible antigen is then measured in both the test sample and in the control sample and these two values compared to determine the presence and activity of interferon inhibitors in the test sample.

Abstract: A method for diagnosing autoimmune disease in mammals, including humans, is described. A blood sample is collected from a subject, and mononuclear white blood cells separated therefrom. The mononuclear cells then are cultured in vitro. Patients with autoimmune disease develop characteristic white cell aggregates with autophagocytosis in the culture. Mononuclear cells from normal patients do not exhibit this cell aggregation with autophagocytosis.