Lymphocyte imbalance in vitiligo patients indicated by elevated CD4+/CD8+ T-cell ratio

Vitiligo is a disorder of pigmentation associated with an autoimmune-mediated loss of melanocytes from the epidermis. Humoral immunity and the involvement of cellular immunity have been investigated in the pathogenesis of vitiligo. We evaluated the role of pro-inflammatory cytokines and lymphocyte fractions in peripheral blood in a cohort of Austrian patients with vitiligo. Morning blood samples from 40 patients with vitiligo were collected. Twenty-one patients had active and 19 had stable vitiligo disease. All patients were suffering from non-segmental vitiligo at different stages of the disease. Sixteen persons presented with an additional autoimmune thyroid disease. To evaluate a possible involvement of proinflammatory cytokines in vitiligo we measured sTNF-RI (soluble tumour necrosis factor receptor I), IL-6 and additionally CIC (circulating immune complexes). We compared these findings to the data from matched normal persons. To investigate the mechanisms of cellular immunity, peripheral blood cell count and lymphocyte subtype analysis by flow cytometry were done. sTNF-RI, IL-6 and CIC serum levels were in the normal range. In the patient group median sTNF-RI level was 1.5 ng/ml and median CIC level was 35.2 microg/ml, and no statistically significant differences to the control group were observed. Median IL-6 level in vitiligo patients was 2.7 pg/ml and in the normal range-but higher than the median level of 0.5 pg/ml observed in normal persons (p < 0.001). Absolute and relative counts of lymphocyte subtypes were normal. The ratio of CD4+/CD8+ T-cells had an elevated median value of 2.6 [quartiles 2.0; 3.1]. 61% of the vitiligo patients had a ratio higher than 2.4, which was the normal cut-off point. In most vitiligo patients the balance of cytotoxic/suppressor and helper/inducer T-cells in peripheral blood is disturbed which might lead to a predominance of T-cell subtypes in the intracutaneous site of autoimmune melanocyte loss.