A low co-expression between CTLA-4 and LIR-1 was observed on CD4+ IFN-γ+ T cells in response either to the parasite lysate (median percentage ± SD = 10±11, range = 2.1–37, Figure 1A, middle panel right graph) or to diphtheria toxoids (median percentage ± SD = 2.9±5.4, range = 0.7–12, Figure 1A, bottom panel right graph). The gene discussed is IFNG; the disease is diphtheria.