RELATIONSHIP AMONG CIRCULATING INTERFERON, TUMOR-NECROSIS-FACTOR-ALPHA, AND INTERLEUKIN-6 AND SEROLOGIC REACTION AGAINST PARASITIC ANTIGEN IN HUMAN HYDATIDOSIS

Human hydatidosis is a parasitic disease vectored by the larval stage cestode Echinoccocus granulosus. It constitutes a major health problem in North Africa. We investigated the production of circulating interf eron (IFN), tumor necrosis factor-alpha (TNF-alpha), and interleukin-6 (IL-6) in Algerian patients with liver, lung, or ocular hydatidosis. In all, 101 serum samples from these patients were analyzed, Immunorea ctivity and cytokine activities were undetectable in sera from ocular hydatidosis patients. However, we observed the presence of IFN (a mixt ure of IFN-alpha, IFN-beta, and IFN-gamma, range 32-500 U/ml), TNF-alp ha (range 32-100 U/ml), and IL-6 (range 32-500 U/ml) in all patients w ho had liver or lung cysts or both and displayed inmunoreactivity agai nst parasitic antigen (antigen 5). After surgical removal of the cysts , serum cytokine levels declined rapidly and were undetectable at 30 d ays. IFN and IL-6 activity was undetectable in sera from two liver hyd atidosis patients who relapsed and did not display any immune response against parasitic antigen. These results suggest that in liver and lu ng hydatidosis, cytokine production contributes to the host defense me chanism against the extracellular parasite.