Abstract
Background: Chagas disease (CD) is characterized by parasite persistence and immunological unbalance favoring systemic inflammatory profile. Chronic chagasic cardiomyopathy, the main manifestation of CD, occurs in a TNF-enriched milieu and frequently progresses to heart failure. Aim of the study: To challenge the hypothesis that TNF plays a key role in Trypanosoma cruzi-induced immune deregulation and cardiac abnormalities, we tested the effect of the anti-TNF antibody Infliximab in chronically T. cruzi-infected C57BL/6 mice, a model with immunological, electrical, and histopathological abnormalities resembling Chagas' heart disease. Results: Infliximab therapy did not reactivate parasite but reshaped the immune response as reduced TNF mRNA expression in the cardiac tissue and plasma TNF and IFNγ levels; diminished the frequency of IL-17A(+) but increased IL-10(+) CD4(+) T-cells; reduced TNF(+) but augmented IL-10(+) Ly6C(+) and F4/80(+) cells. Further, anti-TNF therapy decreased cytotoxic activity but preserved IFNγ-producing VNHRFTLV-specific CD8(+) T-cells in spleen and reduced the number of perforin(+) cells infiltrating the myocardium. Importantly, Infliximab reduced the frequency of mice afflicted by arrhythmias and second degree atrioventricular blocks and decreased fibronectin deposition in the cardiac tissue. Conclusions: Our data support that TNF is a crucial player in the pathogenesis of Chagas' heart disease fueling immunological unbalance which contributes to cardiac abnormalities.