Serum Concentrations of Interferon Gamma (IFN-γ) in Patients with Psoriasis: Correlation with Clinical Type and Severity of the Disease

INTRODUCTION: The etiopathogenesis of psoriasis is still unclear but there is evidence that many of cytokines released by keratinocytes and inflammatory leukocytes may contribute to the induction or persistence of the inflammatory process in psoriasis. AIM: The aim of the study was to evaluate serum concentrations of Interferon gamma (IFN-γ) in patients with psoriasis and the healthy subjects and also to assess a possible association between IFN-γ, clinical type and severity of disease. MATERIAL AND METHODS: The study included a total of 60 patients with psoriasis and 20 healthy subjects in the control group. According to the clinical type of disease, patients with psoriasis were divided into four groups: psoriasis vulgaris (PV), psoriasis erythrodermica (PE), psoriasis pustulosa (PP) and psoriasis arthropatica (PA). Blood samples were collected from all psoriasis patients and from healthy control subjects. Serum IFN-γ levels were measured by an enzyme-linked immunosorbent assay (ELISA) technique. The severity of PV was assessed by Psoriasis Area and Severity Index (PASI) score. RESULTS: The serum concentration of IFN-γ in patients with psoriasis was significantly higher than that in the control group (1.91±1.79 pg/mL vs 0.91±0.38 pg/mL, respectively). Significantly elevated serum IFN-γ concentrations were noticed in patients with PV (2.15±0.30 pg/mL). There was no statistically significant difference between the mean values of IFN- γ compared to the clinical type of psoriasis (p>0.05). In the group of patients with PV 36 (85.71%) patients had mild form of disease with PASI <50, and 6 (14.29%) patients had severe disease with PASI >50. It was not found statistically significant correlation between serum IFN-γ level and PASI score in the group of PV. CONCLUSIONS: The results of our study indicate that psoriasis is associated with significant changes in the serum concentration of IFN-γ. There was no significant correlation between serum IFN-γ concentrations, clinical type of psoriasis and severity of PV evaluated with the use of PASI score.