Recrudescence Induced by Cyclophosphamide of Chronic Trypanosoma cruzi Infection in Mice is Influenced by the Parasite Strain

Reactivation of chronic chagasic patients may occur upon use of immunosuppressive drugs related to kidney or heart transplantation or when they are affected by concomitant HIV infection. This recru-descence, however, does not occur in all chagasic patients exposed to immunosuppressive agents. We therefore investigated the influence of Trypanosoma cruzi strains in the recrudescence of the parasit-ism in mice at the chronic phase treated with cyclophosphamide, an immunosuppressor that blocks lymphocytes DNA synthesis and therefore controls B cells response. A large variation was detected in the percentages of newly established acute phases in the groups of mice inoculated with the different strains. We suggest that reactivation of chronic T. cruzi infections is influenced by the parasite intrin-sic characteristics, a phenomenon that might occur in the human disease. Key words: Trypanosoma cruzi- strains- immunosuppression- cyclophosphamide Trypanosoma cruzi infection in humans is characterized by an acute phase with patent parasitemia which lasts one to two months fol-lowed by a lifelong chronic phase with subpatent parasitemia and scarce tissue parasites. Recrudes