PBMC from leprosy patient groups (PB and MB), leprosy household contacts of PB (HCPB) and MB (HCMB) patients, healthy endemic controls from Meireles (EClow) and from Bom Jardim (EChigh), healthy controls from Porto Alegre (NECBrazil), Dutch tuberculosis patients (TB) and Dutch healthy, non-endemic controls (NECNetherlands) were stimulated with peptides and control antigens, and IFN-γ was measured in culture supernatants on day 5 of incubation. This evidence concerns the gene IFNG and leprosy.