<scp>TNF</scp>‐α inhibitors reduce the pathological Th₁–Th₁₇/Th₂ imbalance in cutaneous mesenchymal stem cells of psoriasis patients

Abstract

Abstract Psoriasis is a disease characterized by an imbalance between Th 1 and Th 17 and Th 2 inflammatory axes, in which cutaneous mesenchymal stem cells ( MSC s) are early involved, as they show a greater relative expression of several genes encoding for Th 1 and Th 17 cytokines. Therapeutic implications of TNF ‐α inhibitors on differentiated skin cells have been largely described in psoriasis; however, their effects on MSC s 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 MSC s isolated from the skin of patients with psoriasis. Resident MSC s 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 Th 1 , Th 2 and Th 17 pathways, both before and after 12 weeks therapy with TNF ‐α inhibitors. The administration of TNF ‐α inhibitors for 12‐weeks acts on MSC s as follows: it reduces the expression of several Th 1 ‐Th 17 cytokines whose levels are elevated at baseline ( IL ‐6, IL ‐8, IL ‐12, IL ‐23A, IFN ‐γ, TNF ‐α, CCL 2, CCL 20, CXCL 2, CXCL 5, IL ‐17A, IL ‐17C, IL ‐17F, IL ‐21, G‐ CSF ). Similarly, it enhances the expression of several Th 2 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 Th 1 –Th 17 vs Th 2 axis in MSC s of patients with psoriasis.