Evaluation of the expression of the stromal cell‐derived factor‐1 alpha (CXCL 12) in psoriatic patients after treatment with Methotrexate

Background CXCL12 has an important role in skin homeostasis and inflammation. Objective In this work, the expression of CXCL12 was evaluated in psoriasis vulgaris, psoriatic arthritis (PsA) patients in relation to disease activity and methotrexate (MTX) therapy. Methods Skin biopsies were obtained from 10 psoriasis vulgaris patients, 10 PsA patients, and 20 controls. The biopsies were repeated 6 weeks after MTX therapy. The biopsies were stained immunohistochemically by stromal dermal factor 1 alpha (CXCL 12) antibody. Results Psoriatic arthritis showed significantly more expression of CXCL 12 than psoriasis vulgaris patients before treatment but not after treatment. There was significant decrease in CXCL 12 expression in the keratinocytes of psoriasis vulgaris patients after MTX therapy than before treatment, P‐value was 0.009. There was no significant difference between pre‐ and post‐treatment in the CXCL 12 expression of keratinocytes of PsA patients, P‐value was 0.093. The percentage decrease of PASI score after treatment showed a moderate correlation with the percentage decrease of CXCL12 expression of the keratinocytes of the total psoriasis patients, r = 0.484, P‐value was 0.015. Conclusion CXCL12 might be involved in the progression of psoriasis vulgaris to PsA. MTX therapy downregulated the expression of CXCL12 of the keratinocytes of psoriasis patients. This downregulation was paralleled by decrease in the PASI score. CXCL12 can be used as a biological marker of disease severity of psoriasis patients.