Background: Psoriasis is a chronic, autoinflammatory disease characterized by activation and differentiation of naive T lymphocytes towards T helper CD4+ (including Th1 and Th17) and T cytotoxic CD8+. Osteopontin (OPN), which plays an important role in both physiological processes and inflammatory, neoplastic and autoimmune diseases, is also considered in the context of psoriasis pathogenesis. Current data indicates that OPN is a multifunctional protein involved in the modulation of Th1 and Th17 cellular responses, in stimulating keratinocyte proliferation, and in the regulation of cellular apoptosis.
Objectives: The assessment of OPN and interleukin 17 (IL-17) concentrations in the peripheral blood of psoriatic patients in comparison to healthy volunteers as well as the correlations of OPN and IL-17 with the severity of psoriasis.
Material and methods: The study included 107 male psoriatic patients and 41 age-matched healthy men. The serum concentrations of IL-17 and OPN were examined using the enzyme-linked immunosorbent assay (ELISA) method. The skin change severity of psoriasis was assessed using the Psoriasis Area and Severity Index (PASI), Body Surface Area (BSA), Physician Global Assessment (PGA), and Dermatology Life Quality Index (DLQI).
Results: Psoriatic patients had significantly higher concentrations of OPN (31.65 ng/mL on average) than the healthy volunteers (11.42 ng/mL on average) (p < 0.001). Interleukin 17 was also higher in psoriatic patients (0.53 pg/mL on average) compared to healthy volunteers (0.09 pg/mL on average) (p < 0.001). There was no significant correlation between OPN and IL-17 concentrations in psoriatic patients and in healthy volunteers. Psoriasis severity correlated positively to IL-17 serum concentration, but not to OPN.
Conclusions: Although the study did not show a relationship between OPN and IL-17 concentrations in psoriatic patients, it should be emphasized that serum concentrations were significantly higher in the patients with psoriasis compared to healthy volunteers.
Keywords: interleukin 17; osteopontin; psoriasis.