Increased IL-31 expression in serum and tissue protein in prurigo nodularis

Prurigo nodularis (PN) is a chronic pruritic skin disease which can greatly impact patients' quality of life. Moreover, the pathogenesis remains unclear, making it a difficult-to-treat condition.

To investigate the expression of interleukin-31 (IL-31) in serum and skin biopsy specimens of PN patients and healthy subjects and identify its possible correlation to disease severity and itch intensity.

Patients with PN and healthy volunteers were recruited for the study. Expression levels of IL-31 were measured by enzyme-linked immunosorbent assay and immunohistochemistry. Baseline characteristics, disease activity, itch intensity, and related laboratory results were collected.

Forty-three PN patients and 31 healthy subjects participated in our study. The PN patients had significantly higher mean serum IL-31 levels than the healthy subjects (52.9 ± 18.2 versus 36.3 ± 10.7 pg/ml, p < 0.001). Epidermal and dermal PN lesions also exhibited significantly higher IL-31 expression compared with the healthy skin (p < 0.001 and p = 0.01, respectively). However, there was no significant difference in serum or lesional expression of IL-31 by disease severity or itch intensity.

Increased IL-31 expression in serum and PN lesions suggests that IL-31 has a potential role in the pathogenesis of PN.