Cutaneous Leishmaniasis: Relative Role of T Cell Subsets

Abstract

Leishmanias are protozoan parasites which are transmitted to their mammalian host by the bite of a sandfly vector (1). Upon entering the host, the flagellated promastigote form of the parasite which is injected by the sandfly is phagocytized by mononuclear phagocytic cells in which it transforms into the aflagellate amastigote form. Following infection of man by Leishmania several different forms of disease can ensue which depend upon the species of Leishmania carried by the sandfly. For example, a cutaneous form of leishmaniasis can be caused by L. major, L. mexicana or L. braziliensis a mucocutaneous form by L. braziliensis and a visceral form by L. donovani In addition, a spectrum of clinical manifestations can be observed in patients suffering from each of these forms of the disease which suggests that the pathologic changes observed in leishmaniasis are due to both the species of the infecting parasite and to the host response to the parasite.