T cells responding to Trypanosoma cruzi detected by membrane TNF-α and CD154 in chagasic patients:

Introduction: Chagas disease is a parasitic infection whose pathogenesis is related to parasite persistence and a dysfunctional cellular immune response. Variability in cytokine secretion among chronic Trypanosoma cruzi-infected patients might preclude the identification of the pool of antigen specific T cells. The goal of this study was to determine the fraction of T cells responding to T. cruzi antigen measured by the expression of membrane TNF-α and CD154. Methods: A total of 21 chagasic patients, 11 healthy and 5 non-chagasic cardiomyopathy controls were analyzed. PBMCs were short-term cultured in the presence of anti-CD28, anti-CD49d, anti-TNF-α, and TACE (TNF-α converting enzyme) inhibitor either under T. cruzi-lysate or polyclonal stimuli. Cells were stained with anti-CD3, anti-CD4, anti-CD8, and anti-CD154, and analyzed with flow cytometry. Results: CD4+ and CD8+ T cells in chagasic patients displayed higher percentages of membrane-bound TNF-α+ and CD154+ compared with controls after T. cruzi-antigen stimulation. Both markers displayed a positive correlation in the T cell subpopulations analyzed. Symptomatic chagasic patients were differentiated from asymptomatic patients based on the expression of CD154 and membrane TNF-α in TCD4+ and TCD8+ compartments, respectively. Conclusions: These results show that both markers could be useful for assessing the pool of antigen-specific T cells in chronic chagasic patients. The goal of this study was to determine the fraction of T cells responding to T. cruzi antigen measured by the expression of membrane TNF-α and CD154. The main findings of our study are (1) CD4+ and CD8+ T cells in chagasic patients displayed higher percentages of membrane-bound TNF-α+ and CD154+ compared with controls after T. cruzi-antigen stimulation; (2) both markers displayed a positive correlation in the T cell subpopulations analyzed; (3) symptomatic chagasic patients were differentiated from asymptomatic patients based on the expression of CD154 and membrane TNF-α in TCD4+ and TCD8+ compartments, respectively. These results show that both markers could be useful for assessing the pool of antigen-specific T cells in chronic chagasic patients.