If we combine the information that mice healed from a primary infection with L. major present the highest proportion of multifunctional CD4+ T cells and protection after a homologous challenge (38), together with the results obtained in healed CL patients after stimulation with L. braziliensis and L. amazonensis promastigotes extracts (39), we can consider the possibility that patients healed from L. braziliensis infection should display better protection to reinfection than L. amazonensis healed patients. The gene discussed is CD4; the disease is infection.