Study of T cell subsets in patients with cutaneous leishmaniasis.

The proportion of T lymphocyte populations was assessed using monoclonal antibodies (OKT3, OKT4, OKT8) and spontaneous E-rosette tests with SRBC (for total and active TE cells) in 36 patients with cutaneous leishmaniasis subdivided according to the clinical variety. The T cell profile was normal in patients with simple cutaneous leishmaniasis of early ulcerative type whereas active TE cells and OKT4 positive cells were reduced in some cases of late ulcerative type. A significant reduction of active TE cells and of OKT4 positive cells (helper/inducer phenotype) and increase of OKT8 positive cells (suppressor/cytotoxic phenotype) was observed in peripheral blood of all patients with persistent active lesions and leishmaniasis recidivans. In patients with highly ulcerated persistent lesions a low proportion of active TE cells was also demonstrated in cellular extracts from dermal tissue. The results support the data obtained in experimental leishmaniasis that lack of helper/inducer cells and generation of suppressor T cells may be responsible for the development of chronic leishmaniasis.