Serum LL-37 and inflammatory cytokines levels in psoriasis

Psoriasis (PsO) is a T-cell-associated inflammatory autoimmune dermatitis. Leucine leucine-37 (LL-37) is upregulated in PsO patients and correlated with the area and severity of PsO. However, the exact relation between LL-37 and T cell-associated inflammation is not well understood. It is very important to clarify the relationship between LL-37 and inflammatory response for clinical diagnosis and treatment of PsO. This study investigated the serum levels of LL-37 and inflammatory cytokines, as well as correlations between them in PsO patients, which aimed to provide new ideas for the diagnosis and treatment of PsO.

PsO patients (n = 50) and healthy volunteers (n = 33) were recruited in this study. Skin specimens were stained with hematoxylin and eosin (H&E). The serum levels of LL-37, T-helper type 1 (Th1, IFN-γ), T-helper type 17 (Th17, IL-17), T-helper type 22 (Th22, IL-22), and T-helper type 2 cytokines (Th2, IL-4) were assessed by enzyme-linked immunosorbent assay. Some of the patients were re-recruited after treatment to evaluate LL-37 and cytokines levels.

Pathological changes were observed in PsO skin lesions. LL-37, IFN-γ, IL-17, and IL-22 serum levels were much higher in PsO patients than those in healthy volunteers (p < .001), and posttreatment reduction was observed in five patients. However, no remarkable difference in IL-4 level (p > .05) was found. LL-37 level was positively correlated with IFN-γ, IL-17, and IL-22 levels (p < .001) in PsO patients.

LL-37 expression was significantly associated with inflammatory response, which may provide us new ideas for diagnosing and monitoring disease activity of PsO.