Caracterização fenotípica e funcional de monócitos e sua associação com diferentes subpopulações de células T CD4-CD8- nas formas clínicas indeterminada e cardíaca da doença de Chagas

Abstract

Immune cells play important role in the inflammation observed in Chagas diseases (CD), and among them, we have identified double negative T cells (CD4-CD8-) as an important source of cytokines. DN T cells are preferentially activated by molecules of the CD1 family, which are expressed by antigen-presenting cells, including monocytes. Trypanosoma cruzi’s membrane is rich in lipid and glyconjugate antigens, which are immunogenic and potentially activate DN T-cells. This work aims to characterize phenotypically and functionally monocytes from patients with the different clinical forms of CD, determining the expression of molecules from the CD1 family, cytokines and their receptors, correlating these characteristics with the activation of DN T-cells. To do so, we obtained peripheral blood mononuclear cells from 13 CARD and 8 IND patients, cultured in vitro in the presence of trypomastigote antigens (TRP) or media, and we analyze by flow cytometry. We observed that CARD monocytes have an inflammatory profile with high TNF expression compared to the IND group. TRP increases the frequency of regulatory molecules such as Fas-L and PDL-1 in CARD monocytes. CARD monocytes with TRP had an increase in classical and intermediate monocytes, related to a worse cardiac function. Furthermore, the distribution of CD1 isoforms in monocyte subpopulations is different between the clinical forms IND and CARD: there is a higher expression of CD1a, b and d in CARD monocytes, and a higher frequency of CD1c+ and CD1d+ in IND monocytes. CD1d+ monocytes from CARD patients, with or without stimulation, exhibited an inflammatory profile with high TNF-α expression, compared to the IND group; and were strongly correlated with DN TNF-α+ T cells, only in the CARD group. Overall, our data have shown that monocytes from patients of the clinical form IND and CARD have large phenotypic and functional differences, and CARD monocytes seem more reactive to stimulation with T. cruzi antigen than IND monocytes, which may have important implications in the clinical outcome of these patients.