Immunocytochemical characterization of immune cells in lesions of American cutaneous leishmaniasis using novel T cell markers

Abstract

Some recently defined lymphocyte immunophenotypes were determined in lesions of patients with American cutaneous leishmaniasis (ACL). New monoclonal antibodies have allowed the demonstration of cell surface antigens of T lymphocytes, such as CD45RA and CD45RO, which recognize different maturational stages of the same T CD4+ cell subgroup: ‘virgin’ (CD4+CD45RA+) and ‘memory’ (CD4+CD45RO+) T cells respectively. The CD4/CD8 cell ratios were higher in mucocutaneous leishmaniasis (MCL) than in localized cutaneous leishmaniasis (LCL) lesions. Diffuse cutaneous leishmaniasis (DCL) has the highest values of ‘virgin’ T cells; LCL and MCL patients have lower values, similar to each other. ‘Memory’ T cells were higher in MCL than in LCL or DCL. The ratio of ‘memory’/‘virgin’ T cells was 7.9 for LCL, 9.6 for MCL and 2.5 for DCL. The highest value for IL-2 receptor positive cells (CD25) was observed in LCL, whereas single CD45RO-immunoreactive cells showed a peak value in DCL patients. HLA-DR+ cells were present in all three clinical forms of ACL. MCL patients showed a lack of epithelial Langerhans cell (CDla+) in the nasal mucosa.