Cutaneous leishmaniasis in Ethiopia: I. Lymphocyte transformation and antibody titre

The Ethiopian cutaneous leishmaniasis (ECL) caused by Leishmania aethiopica manifests itself in two different forms: The self-healing localized form (LCL) and the non-self-healing diffuse cutaneous leishmaniasis (DCL). In patients suffering from these two forms of ECL, the Leishmania antigen induced in-vitro lymphocyte response and the Leishmania specific antibody titres were investigated. Whole promastigotes and a soluble fraction thereof were used as antigens and antibody titres were determined by a newly developed enzyme-immunosorbent assay (ELISA). Mononuclear cells from the majority of patients but not from healthy donors proliferated in response to soluble Leishmania antigen. In contrast, whole promastigotes induced a proliferation in both patients and controls. Only DCL-cases failed to proliferate in response to both leishmanial antigens. On the average, sera from DCL-patients contained higher titres of Leishmania specific antibodies than those from LCL-patients. One practical implication of these results is that lymphocyte proliferation in combination with specific antibody titre can be used as a reliable diagnostic tool in ECL.