Studies on spontaneous production of gamma-interferon in Behçet's disease.

Gamma-interferon (IFN-gamma) is detected at a higher level in the sera of patients with Behçet's disease than in control subjects. To investigate the cellular source of IFN-gamma, peripheral blood lymphocytes (PBL) from patients were cultured and found to produce IFN-gamma spontaneously in their fresh culture fluids. The average IFN titers in cultures of the patients' PBL were significantly higher than those of the control cultures (p less than 0.0001). The IFN activity was significantly higher in cultures of the patients in the ocular convalescent stage than in the exacerbation stage (p less than 0.0001), as was the case with serum interferon activity. Fractionation of PBL showed that only T gamma lymphocytes of the patients produced IFN-gamma spontaneously in the cultures. No IFN was produced in the culture fluids of T non-gamma cells, non-T cells or macrophages. T gamma cells and IFN-gamma may therefore play a significant role in the immunopathophysiology of Behçet's disease.