The importance of our findings is enhanced considering three rare achievements (76): (1) we found CD4 Th1-cell epitopes of a CD4 T cell mediated immunosupressive disease; (2) they are highly promiscuous and bind to many HL-DR allotypes; and (3) they are extremely conserved and present in Leishmania of two subgenera that cause visceral, cutaneous, diffuse, and mucocutanoeus leishmaniasis. The gene discussed is CD4; the disease is leishmaniasis.