Serum immunoglobulin E and Interleukin‐17 levels in patients with chronic plaque psoriasis: A <scp>case–control</scp> study

Background Psoriasis is a skin disorder mainly mediated by T helper (Th)-1 and Th-17 cells. Recently, high serum immunoglobulin (Ig)-E levels were detected in psoriatic patients. The etiopathogenesis of IgE overproduction in psoriatic patients is still unknown, but IL-17 has been suggested to be responsible for this abnormality. Objective To compare levels of IgE and IL-17 in the sera of patients with chronic plaque psoriasis (CPP) to healthy subjects. Methods This study included 40 patients with CPP and 40 age- and sex-matched healthy individuals. Serum IgE and IL-17 concentrations were measured using the enzyme-linked immunosorbent assay (ELISA) technique. Results Levels of IgE and IL-17 were significantly higher in the sera of psoriatic patients than in controls (P= 0.001 & 0.024, respectively). Psoriatic patients with abnormally high serum IgE levels had higher serum IL-17 levels than those with normal serum IgE levels, but the difference was statistically insignificant (P=0.080). Furthermore, no significant correlation was found between serum IgE and IL-17 concentrations in psoriatic patients (P=0.385). Conclusions It is possible that IgE and IL-17 interact in psoriasis pathogenesis; however, this was not evident in the current study, possibly due to the small sample size. Therefore, other potential causes of elevated IgE levels in psoriatic patients should be investigated. Moreover, the interaction between IgE and IL-17 should be investigated in patients with other clinical variants of psoriasis.