Although the intrathymic checkpoints necessary to avoid the maturation of T cells expressing potentially autoreactive “forbidden” T-cell receptors are present in the acute phase of murine Chagas disease, circulating CD4+CD8+ T cells have been reported in humans as well as in animals such as mice, chicken, swine, and monkeys [9, 62, 85]. The gene discussed is CD8A; the disease is Chagas disease.