Increased tissue expression of IL-31 in patients with psoriasis

Psoriasis is a chronic inflammatory skin disease, and its pathogenesis remains unclear. Although many studies have demonstrated the role of serum interleukin-31 (IL-31) in psoriasis, only one study has examined histopathological expression in lesional skin. This study aimed to investigate the expression of IL-31 in skin biopsy specimens of psoriasis patients compared to healthy subjects and identify its possible correlation to disease severity and itch intensity. Psoriasis patients and healthy volunteers were recruited. Four-millimeter punch biopsy was performed at the lesional skin of psoriasis patients and normal skin of healthy subjects. Expression of IL-31 was measured by immunohistochemistry. Baseline characteristics, disease activity, itch intensity, and related laboratory results were collected. Twenty-six biopsy specimens of psoriasis patients and 10 tissue samples of healthy subjects were evaluated. Epidermal and dermal psoriasis lesions had significantly higher IL-31 expression compared to the healthy skin (P < 0.001). However, there was no significant difference in lesional expression of IL-31 by disease severity or itch intensity. Increased IL-31 expression in the lesions of psoriasis patients suggests the involvement of IL-31 in the pathogenesis of psoriasis.