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 interferon (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 with analyzed. Immunoreactivity and cytokine activities were undetectable in sera from ocular hydatidosis patients. However, we observed the presence of IFN (a mixture of IFN-alpha, IFN-beta, and IFN-gamma, range 32-500 U/ml), TNF-alpha (range 32-100 U/ml), and IL-6 (range 32-500 U/ml) in all patients who had liver or lung cysts or both and displayed immunoreactivity against parasitic antigen (antigen 5). After surgical removal of the cysts, serum cytokine levels declined rapidly and were undetectable at 30 days. IFN and IL-6 activity was undetectable in sera from two liver hydatidosis patients who relapsed and did not display any immune response against parasitic antigen. These results suggest that in liver and lung hydatidosis, cytokine production contributes to the host defense mechanism against the extracellular parasite.