EFFECT OF CHEMOTHERAPY WITH PRAZIQUANTEL ON ENDOGENOUS INTERLEUKIN 12 (IL-12) IN SCHISTOSOMA MANSONI INFECTION IN MICE IN RELATION TO IMMUNOPATHOLOGICAL RESPONSE
Mayssa M. Zaki1; Ihsan H. Hassan2; Eman Y. Shoeib1; Amany A. Abd El-Aal1; Soheir Ismail3
1Parasitology Department, Faculty of Medicine, Cairo University, Departments of 2Pathology and 2Internal Medicine, National Hepatology and Tropical Medicine Research Institute, Cairo
The development of hepatic fibrosis and portal hypertension is the principal cause of morbidity and mortality in schistosomiasis mansoni infection. Nevertheless, relatively little is known about the mechanisms that lead to excessive collagen deposition during infection with Schistosoma mansoni. In the murine model, infection leads to significant egg-induced granuloma formation, tissue eosinophilia, and hepatic fibrosis. Pathology has been linked to type 2 immunological responses. To evaluate the effect of praziquantel on endogenous IL-12 and its subsequent immunomodulatory effect on granuloma formation, the immune response to S. mansoni infected mice was studied both with and without treatment. Serum levels of IL-12 was estimated at weeks 4, 8, 12, 16 and 20 post infection in both treated and untreated mice groups. Egg count/gm tissue (liver and intestine) was calculated and oogram of the intestine was used to determine the number of immature and mature eggs in the same groups. Finally, histopathologic examination of liver was done at the same time intervals to correlate the serum levels of IL-12 with the granuloma formation. Together, these data revealed the important effect of praziquantel in inducing IL-12 production which has a key role in immunomodulation of granuloma induced by eggs. Also this work showed that cases with low serum IL-12 level in the acute phase of the disease are suspected to be more liable to develop the debilitating fibrogranulomatous form of the disease with subsequent fatal complications, suggesting that IL-12 level could be used as an indicator for the prognosis of the disease and might help in immunotherapeutic trials especially in cases resistant to treatment.