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.

Vitiligo patients present lower plasma levels of alpha-melanotropin immunoreactivities.

Vitiligo is a depigmenting disorder characterized by the development of white patches with evidence in favour of an autoimmune mechanism. We investigated the role of melanotropins and the plasma levels of alpha-melanotropin and ACTH-like immunoreactivities in 40 vitiligo patients with the aim of detecting a possible influence of neuropeptide regulation of immunity. Twenty-one patients had active and 19 had stable vitiligo disease, 16 persons presented with an additional autoimmune thyroid disease. Median alpha-MSH levels in vitiligo patients were 6.4p mol/l [5.2;11.3] and significantly lower than in control persons with 11.4 pmol/l [8.6;13.4]. Median ACTH levels of the affected patient group were 17 pg/ml [10.5;28] and appeared statistically higher than 12 pg/ml [7;17] measured in the control group. Measured morning cortisol levels in both groups were not significantly different. Reduced cutaneous alpha-MSH immunoreactivities have been related to the development of autoimmune-induced depigmenting disorders. Our data present lower alpha-MSH plasma levels in vitiligo patients which may be associated with the development of vitiligo depigmentation and may indicate a condition of impaired peripheral tolerance in this autoimmune disorder.

Plasma levels of alpha-melanotropin and ACTH-like immunoreactivities do not vary by season or skin type in women from southern and central Europe.

Melanotropins (MSH) are involved in tanning by stimulating melanocytes via the activation of the melanocortin-1 receptor to melanin production. Its main site of production is the pituitary gland, but alpha-MSH and related ACTH peptides are produced at other sites, including the skin. It has been hypothesized that systemic levels of alpha-MSH are controlled by a varying UV radiation (UVR) exposure. A seasonal rhythm of plasma levels has been proposed by some authors. We investigated healthy females in southern Spain and central Austria in summer and winter. The alpha-MSH and ACTH-like immunoreactivity plasma levels did not present marked differences between the groups of Malaga and Linz, dark and light skin and between seasons. An association of alpha-MSH to ACTH or cortisol levels could not be observed. Individual values of alpha-MSH were shown to be relatively constant at both times of measurement (p<0.05 by rank correlation) indicating an independent personal disposition for individual systemic alpha-MSH immunoreactivity levels. Our data do not support the concept of a marked involvement of melanotropins of pituitary origin in tanning, and no seasonal rhythm was observed.