Bimodal distributions of anti-Trypanosoma cruzi antibody levels in blood donors are associated with parasite detection and antibody waning in peripheral blood.

This study confirms the bimodal distribution in the signal of different antibody serological assays for detecting T. cruzi infection, including highly sensitive assays. In this work, threshold values were established to distinguish between two populations (or groups) of subjects with this infection: one with high antibody levels, where parasitemia persists for many years, and another with low antibody levels, corresponding with the absence or low levels of parasitemia. These individuals showed they could control the infection, as low antibody levels result from low antigenic stimulation. Additionally, we observed that the decline in antibody levels is significantly more significant among donors with low antibody levels during follow-up