Lymphocyte phenotypes and HLA-DR expression in the lesions of cutaneous leishmaniasis and their draining lymph nodes

ABSTRACT

T-lymphocyte phenotypes and human leukocyte antigen-DR expression [HLA-DR] expression in skin lesions and draining lymph nodes of zoonotic leishmaniasis caused by Leishmania major were studied. T lymphocytes were the dominant cells in the lymphocytic preponderance type of lesion. They were lowest when the parasitized macrophage was the dominant cell or when the reaction consisted of an equal admixture of lymphocytes, macrophages and plasma cells. Both inducer/helper and suppressor/ cytotoxic T cells were present in varying proportions. The latter were thought to be suppressor rather than cytotoxic cells. Their late appearance in the host reaction was believed to play a major role in halting the inflammatory response. Low levels of cells expressing the suppressor/cytotoxic phenotype and the continued presence of antigen in macrophages was associated with persistence of the lesions even when parasites were largely eliminated after specific antileishmanial therapy. Such lesions healed after local or systemic steroid therapy. The majority of cells in the dermal infiltrate were HLA-DR positive. Keratinocytes also expressed HLA-DR