Increased Natural Killer (NK)-cell cytotoxicity and Trypanosoma cruzi-specific memory B cells in subjects with discordant serology for Chagas disease

Abstract

The presence of memory T cell specific for Trypanosoma cruzi in subjects with discordant serology for Chagasdisease supports a cleared infection in these subjects. Using high-dimensional flow cytometry, ELISPOT assaysand quantitative PCR, antibody-secreting cells and memory B cells specific for T. cruzi, total B-cell phenotypes,innate immune responses and parasite DNA were evaluated in serodiscordant, seropositive and seronegativesubjects for T. cruzi infection. T. cruzi-specific memory B cells but no antibody-secreting cells specific for T. cruzi,increased proportion of nonclassical monocytes and increased levels of polyfunctional NK cells were found inserodiscordant compared with seropositive subjects. None of the serodiscordant subjects evaluated showeddetectable parasite DNA, most of them did not show cardiac abnormalities and a group of them had hadconfirmed positive serology for Chagas disease. The unique immune profiles in serodiscordant subjects supportthat T. cruzi infection was cleared or profoundly controlled in these subjects.