Assessment of CD8(+) T cell differentiation in Trypanosoma cruzi-infected children.

We previously reported that the T cell compartment in chronically Trypanosoma cruzi-infected adult subjects display functional and phenotypic signs of immune senescence. This study aimed to investigate the differentiation and the senescent profile of the overall CD8(+) T cell compartment in T. cruzi-infected children at the early stage of the disease. We found a lower percentage of naive (CD27(+)CD28(+)CD45RA(+)) and early antigen-experienced (CD45RA(-)CD27(+)CD28(+)), and higher percentages of late differentiated antigen-experienced (CD45RA(-)CD27(-)CD28(-)) CD8(+) T cells in T. cruzi-infected children as compared with age-matched uninfected controls. The expression of the interleukin (IL)-7R is also decreased on naive and on antigen-experienced total CD8(+) T cells with various degrees of differentiation. Conversely, the expression of HLA-DR, caspase-3, and CD57 did not vary on the total CD8(+) T cell compartment. These findings suggest that the duration of the infection is relevant in the process of immune senescent that this parasite can induce.