Detection of early apoptosis and cell death in T CD4+ and CD8+ cells from lesions of patients with localized cutaneous leishmaniasis.
Human localized cutaneous leishmaniasis (LCL), induced by Leishmania braziliensis, ranges from a clinically mild, self-healing disease with localized cutaneous lesions to severe forms which can present secondary metastatic lesions. The T cell-mediated immune response is extremely important to define the outcome of the disease; however, the underlying mechanisms involved are not fully understood. A flow cytometric analysis of incorporation of 7-amino actinomycin D and CD4+ or CD8+ T cell surface phenotyping was used to determine whether different frequencies of early apoptosis or accidental cell death occur at different stages of LCL lesions. When all cells obtained from a biopsy sample were analyzed, larger numbers of early apoptotic and dead cells were observed in lesions from patients with active disease (mean = 39.5 +/- 2.7%) as compared with lesions undergoing spontaneous healing (mean = 17.8 +/- 2.2%). Cells displaying normal viability patterns obtained from active LCL lesions showed higher numbers of early apoptotic events among CD8+ than among CD4+ T cells (mean = 28.5 +/- 3.8 and 15.3 +/- 3.0%, respectively). The higher frequency of cell death events in CD8+ T cells from patients with LCL may be associated with an active form of the disease. In addition, low frequencies of early apoptotic events among the CD8+ T cells were observed in two patients with self-healing lesions. Although the number of patients in the latter group was small, it is possible to speculate that, during the immune response, differences in apoptotic events in CD4+ and CD8+ T cell subsets could be responsible for controlling the CD4/CD8 ratio, thus leading to healing or maintenance of disease.
Bertho
A L
AL
Laboratório de Imunidade Celular e Humoral em Protozooses, Departamento de Protozoologia, Instituto Oswaldo Cruz, Fundação do Instituto Oswaldo Cruz, Rio de Janeiro, RJ, Brasil.
Santiago
M A
MA
Da-Cruz
A M
AM
Coutinho
S G
SG
D000328:Adult; D017209:Apoptosis; D015496:CD4-Positive T-Lymphocytes / Q000502:physiology*; D018414:CD8-Positive T-Lymphocytes / Q000502:physiology*; D016923:Cell Death; D004396:Coloring Agents / Q000008:administration & dosage; D005260:Female; D005434:Flow Cytometry; D006801:Humans; D016773:Leishmaniasis, Cutaneous / Q000276:immunology / Q000503:physiopathology*; D008297:Male
D004396:Coloring Agents