Reduction of skin-homing cytotoxic T cells (CD8+ -CLA+) in patients with vitiligo.

BACKGROUND: Vitiligo is a frequently acquired, hereditary disease, characterized by achromic macules due to the absence of melanocytes. In contrast with earlier studies, in which the main pathogenic role was attributed to anti-melanocyte antibodies, recent papers have emphasized a role for CD8(+) cytotoxic T lymphocytes in melanocyte destruction. Fifteen percent of peripheral T cell express cutaneous lymphocyte-associated antigen (CLA), responsible for skin-homing T cell. Phototherapy is used to treat patients with generalized vitiligo and it has been shown to interfere with CLA(+) T cells in other skin diseases. OBJECTIVE: To describe peripheral blood T cell subpopulations' frequency and ability to express the skin-homing molecule (CLA) in patients with non-segmental vitiligo, before and after photochemotherapy (PUVA). PATIENTS AND METHODS: Twenty-two patients with generalized and active spreading vitiligo were submitted to 30 PUVA-8MOP sessions. Lymphocyte immunophenotyping was performed by flow cytometry using anti-CD3, anti-CD8 and anti-CLA monoclonal antibodies. Fifteen healthy volunteers, sex- and age-matched, were included as a control group. RESULTS: CD8(+) -CLA(+) T cells were significantly reduced in number in untreated vitiligo patients (P=0.008) when compared with control individuals, albeit with a more intense CLA expression (P=0.028). These findings were not altered after PUVA. No significant difference was noticed in CD4/CD8 ratios nor in CD4-CLA(+) T cell numbers between vitiligo patients and controls, both before and after PUVA. CONCLUSIONS: CD8-CLA(+) T cells are reduced in peripheral blood of patients with non-segmental vitiligo. This finding may be related to the previously reported increase of CD8(+) cells in both lesions and perilesional skin of these patients.

Redução dos linfócitos T-CD8+ citotóxicos observada com a terapia Puva em paciente com vitiligo / Reduction of cytotoxic T-CD8+ lymphocytes observed during PUVA therapy in a patient with vitiligo

Na patogênese do vitiligo tem-se enfatizado o papel das células T citotóxicas. Identificadas pelo antígeno linfocitário cutâneo (CLA), essas células já foram descritas no sangue de pacientes com outras dermatoses e podem ser depletadas pela fototerapia concomitantemente à melhora clínica. Descreve-se caso de vitiligo generalizado com melhora clínica expressiva após Puva, no qual houve redução de 25% dos linfócitos T CD8+-CLA+ circulantes.

The role of cytotoxic T cells (CD8+) has been emphasized in the pathogenesis of vitiligo. This cell population, identified by a skin homing molecule (cutaneous lymphocyte associated antigen Â- CLA), has been described in patients with other dermatoses and can be reduced with phototherapy. The authors present the case of a patient with generalized vitiligo and clinical recovery after PUVA parallel to a 25% reduction in CD8+-CLA+ T cells in the peripheral blood.