Chagasic patients are able to respond against a viral antigen from influenza virus

Background: Trypanosoma cruzi, the etiological agent of Chagas' disease, is an obligate intracellular parasite which induces a CD8⁺ T cell immune response with secretion of cytokines and release of cytotoxic granules. Although an immune-suppressive effect of T. cruzi on the acute phase of the disease has been described, little is known about the capacity of CD8⁺ T cell from chronic chagasic patients to respond to a non-T. cruzi microbial antigen.Methods: In the present paper, the frequency, phenotype and the functional activity of the CD8⁺ T cells specific from Flu-MP*, an influenza virus epitope, were determined in 13 chagasic patients and 5 healthy donors.Results: The results show that Flu-MP* peptide specific CD8⁺ T cells were found with similar frequencies in both groups. In addition, Flu-MP* specific CD8⁺ T cells were distributed in the early or intermediate/late differentiation stages without showing enrichment of a specific sub-population. The mentioned Flu-MP* specific CD8⁺ T cells from chagasic patients were predominately T_EM (CCR7- CD62L-), producing IL-2, IFNγ, CD107a/b and perforin, and did not present significant differences when compared with those from healthy donors.Conclusions: Our results support the hypothesis that there is no CD8⁺ T cell nonspecific immune-suppression during chronic Chagas disease infection. Nonetheless, other viral antigens must be studied in order to confirm our findings.