IL-12 ENHANCES PROLIFERATION OF PERIPHERAL-BLOOD MONONUCLEAR-CELLS FROM CHAGAS-DISEASE PATIENTS TO TRYPANOSOMA-CRUZI ANTIGEN

Chagas' disease is caused by infection with Trypanosoma cruzi. Patient s in the chronic phase of infection were grouped as belonging to the a symptomatic (or indeterminate), cardiac and cardiac plus digestive for ms, Previous studies have described abnormal immune responsiveness by peripheral blood mon,nuclear cells (PBMC) from chronic chagasic patien ts, We report significant parasite antigen (T-Ag)-stimulated PBMC prol iferative responses to be present in all three groups of patients, Tre atment of T-Ag-stimulated cultures with rIL-12 significantly amplifies proliferative responses in all patients' groups, with similar rates o f increment, IL-12 enhances T-Ag-specific lymphoproliferation without increasing proliferation of unstimulated PBMC from normal individuals or from patients. Comparatively, treatment with rIL-2 enhances both T- Ag-specific and unstimulated proliferation by PBMC from patients and n ormals. Thus, IL-12 acts on pre-activated cells while IL-2 also stimul ates resting cells. No synergism was obtained by the combined use of I L-12 and IL-2. Therefore IL-12 can act as a more selective amplifier o f T. cruzi reactive cells than IL-2. IL-12, by enhancing parasite-anti gen specific immunity, could be of potential therapeutic use to contro l reactivated T. cruzi infections concomitant to AIDS or other situati ons of immunosuppression. (C) 1997 Elsevier Science B.V.