Decreased total numbers of peripheral blood lymphocytes with elevated percentages of CD4+CD45RO+ and CD4+CD25+ of T-helper cells in non-segmental vitiligo.

Vitiligo is a disorder involving progressive skin depigmentation caused by host mediated destruction of melanocytes. Its pathogenesis is known to correlate with elevated levels of activated skin-infiltrating T lymphocytes and is presumed to be autoimmune in nature. In the present study, we characterize the immunophenotype of peripheral blood T cells from vitiligo patients, with the objective of developing an investigative and diagnostic tool for the disease, using analysis of peripheral blood. Subjects for this investigation included 32 patients diagnosed with non-segmental vitiligo and 28 age-and gender-matched, normal, healthy control participants. Whole venous blood taken from each subject was analyzed using 2-color flow cytometry for immunologically-relevant lymphocyte subsets. When compared with healthy control subjects, peripheral blood from individuals with vitiligo was found to have lower total numbers of lymphocytes (p<0.039). Vitiligo patients also had elevated percentages of memory (CD4+CD45RO+) T cells; (p<0.05), but NK-T cells (CD3+CD16+CD56+) and naive T cells (CD4+CD45RA+) were present at lower total numbers and percentages than in healthy controls (p<0.01 and 0.05 respectively). Blood from severely afflicted subjects exhibited elevated CD3+HLADR+ and CD4+CD45RO+ as well as lower percentages of NK-T cells (p<0.05) when compared with mild cases. In conclusion, disease-associated, peripheral blood lymphocyte immunophenotypic profiles of vitiligo patients are consistent with the hypothesis of T cell activation as a major feature of the disorder. These include elevated memory and reduced naive T cell percentages and increased expression of the activation-associated surface antigen CD25. These changes presumably reflect increased antigen-mediated activation. Moreover, because a corollary effect is increased activation-induced cell death (AICD), lower overall lymphocyte counts observed in vitiligo-afflicted subjects is also expected.