American cutaneous leishmaniasis is characterized by a spectrum of clinical manifestations. These include localized, often self-healing single lesions, intermediate forms which frequently produce mucosal lesions and often show exaggerated delayed-type hypersensitivity (DTH), and the rare diffuse cutaneous leishmaniasis in which no reaction of protective cell-mediated immunity or DTH can be demonstrated. Clinical, pathological and immunological studies have begun to unravel some of the mechanisms associated with different disease manifestations, dependent on complex interactions between the host immune response, measured in terms of indices including lymphocyte subsets and lymphokines in vitro and within active lesions, and different species of Leishmania.

The clinical efficacy of immunotherapy for localized American cutaneous leishmaniasis with a combination of heat-killed Leishmania mexicana amazonensis promastigotes and viable BCG (bacille Calmette Guérin) has been compared with meglumine antimoniate chemotherapy and with BCG alone in a controlled clinical study in 217 patients. The results in the first two groups were comparable, with greater than 90% clinical cures with an average time of 16-18 w required for healing. The cure rate was considerably lower (42%) and more prolonged in the group receiving BCG alone. Secondary effects were observed in less than 5% of the patients receiving combined immunotherapy or BCG alone. In contrast, 49% of the patients receiving chemotherapy showed side effects. High therapeutic efficacy was also observed using combined immunotherapy in patients with intermediate and diffuse cutaneous leishmaniasis who were previously unresponsive to chemotherapy. Cure or clinical improvement was seen in all 11 patients with intermediate forms of the disease, and marked clinical improvement was observed in 9 of 10 patients with diffuse disease. The results on the efficacy of the combined vaccine in immunotherapy for American cutaneous leishmaniasis provide a strong rationale for studying its effectiveness in prophylactic trials.

No abstract

Severe mucocutaneous (MCL) and diffuse (DCL) forms of American cutaneous leishmaniasis (ACL

Miltefosine produced a dramatic clinical and parasitological response in patients with DCL and improvement continued during drug administration, but with a single exception all patients presented new lesions after suspension of treatment. There was no histological or skin test evidence to suggest the development of CMI during treatment, which may be an indispensable criterion for the evaluation of potentially effective drugs against DCL.