Effects of α-melanocyte-stimulating hormone on the production of TNF-α and IL-10 by peripheral blood mononuclear cells from patients with psoriasis

Objective To investigate the effects of alpha-melanocyte-stimulating hormone (alpha-MSH) on the production of tumor necrosis factor-alpha (TNF-alpha) and intedeukin-10 (IL-10) by peri-pheral blood monohuclear cells (PBMCs) from patients with psoriasis vulgaris. Methods Heparinized peri-pheral blood was obtained from 20 patients with psoriasis vulgaris and 10 healthy human controls. PBMCs were isolated, cultured in complete medium, and stimulated with phytohemagglutinin (PHA) alone, the com-bination of PHA and various concentrations of alpha-MSH, or nothing. After another 48-hour culture, ELISA and real-time PCR were performed to measure the secretion levels of TNF-alpha and IL-10 in the super-natants of cultured PBMCs as well as the mRNA expression levels of TNF-alpha and IL-10 in PBMCs. Results The secretion level of TNF-alpha in the supematants of patient-derived PBMCs stimulated by nothing or PHA alone was significantly higher than that from normal control-derived PBMCs (329.87 ± 99.33 ng/L vs 116.95 ± 37.15 ng/L, 1756.01 ± 183.60 ng/L vs 1287.30 ± 152.36 ng/L, both P<0.01). alpha-MSH of all tested concentrations (10-13, 10-11, 10-7,mol/L) could inhibit the secretion of TNF-alpha by PBMCs com-pared with PHA alone (all P < 0.01), and the maximum effective concentration was 10-13 mol/L. On the con-Wary, a significant decrease was observed in the secretion level of IL-10 in the supematants of patient-derived PBMCs stimulated by nothing or PHA alone compared with normal control-derived PBMCs (P <0.05 or 0.01). Moreover, the secretion of IL-10 by PBMCs was promoted by alpha-MSH of all tested con-centrations (P < 0.01 or 0.05), with the maximum effective concentration being 10-13 mol/L (P < 0.01). The alpha-MSH of 10-13 mol/L down-regulated the mRNA expression of TNF-alpha (P < 0.001), but up-regnlated that of IL-10 (P < 0.001) in PHA-stimulated PBMCs from patients. Conclusion alpha-MSH can regulate the production of TNF-alpha and IL-10 by PHA-stimulated PBMCs from patients with psoriasis vulgaris.