Peripheral Whole Blood FOXP3 TSDR Methylation and Plasma IL-10, IL-17, IL-35, and IL-36 Levels in Psoriasis

Recent studies have shown that methylation levels in regulator T-cells, which are characterized by high FOXP3 expression, pro-inflammatory, and anti-inflammatory cytokines are involved in the pathogenesis of psoriasis. Our aim was to determine the levels of FOXP3 TSDR methylation, FOXP3 mRNA expression, and levels of IL-10, IL-17, IL-35, and IL-36 in patients with psoriasis. In addition, we intended to investigate the relationship of these parameters with disease severity and treatment status. We performed a hospital-based case-control study on 38 patients with psoriasis and 20 controls. We performed HRM-PCR, real-time PCR, and ELISA to determine FOXP3 TSDR methylation status, FOXP3 mRNA expression, and interleukin levels, respectively. FOXP3 TSDR was found to be methylated both in the patient and control groups. There was no significant difference between the melting temperatures and FOXP3 mRNA levels between the groups. Among the cytokines, only IL-10 was found to be significantly lower in patients. Positive correlation was found between IL-35 levels and psoriasis area and severity index (PASI) scores in all patients; IL-17A levels and PASI scores in patients with mild psoriasis, and IL-36γ levels and PASI scores in patients with moderate-to-severe psoriasis. The production of IL-10 seems to be impaired in patients with psoriasis. Positive correlation between the levels of IL -35, IL-17A, and IL-36γ and disease severity supports the clinical implication of these cytokines in psoriasis.