TNF-α inhibitors reduce the pathological Th1 -Th17 /Th2 imbalance in cutaneous mesenchymal stem cells of psoriasis patients.

Psoriasis is a disease characterized by an imbalance between Th1 and Th17 and Th2 inflammatory axes, in which cutaneous mesenchymal stem cells (MSCs) are early involved, as they show a greater relative expression of several genes encoding for Th1 and Th17 cytokines. Therapeutic implications of TNF-α inhibitors on differentiated skin cells have been largely described in psoriasis; however, their effects on MSCs derived from patients with psoriasis have been only partially described. The aim of this work was to evaluate the effect of TNF-α inhibitors on cytokine milieu expressed by MSCs isolated from the skin of patients with psoriasis. Resident MSCs from skin of patients with psoriasis and healthy subjects have been isolated, characterized and profiled by PCR and ELISA for the expression of 22 cytokines involved in Th1 , Th2 and Th17 pathways, both before and after 12 weeks therapy with TNF-α inhibitors. The administration of TNF-α inhibitors for 12-weeks acts on MSCs as follows: it reduces the expression of several Th1 -Th17 cytokines whose levels are elevated at baseline (IL-6, IL-8, IL-12, IL-23A, IFN-γ, TNF-α, CCL2, CCL20, CXCL2, CXCL5, IL-17A, IL-17C, IL-17F, IL-21, G-CSF). Similarly, it enhances the expression of several Th2 cytokines which are underexpressed at baseline (IL-2, IL-4, IL-5), reducing the expression of those overexpressed at baseline (TGF-β and IL-13). TNF-α inhibitors could contribute to reduce the pathological imbalance between the Th1 -Th17 vs Th2 axis in MSCs of patients with psoriasis.