Assessment of Serum Interleukin-15 in Patients With Psoriasis: A Prospective Case-Control Study

Objective: Interleukin (IL)-15, a pro-inflammatory cytokine, has been shown to be upregulated in various autoimmune and inflammatory disorders. Although its relationship with pathogenesis of psoriasis is unclear, this research aimed to assess the possible role of IL-15 in the pathogenesis of psoriasis and its correlation with the disease severity. Methods: Fifty patients with chronic plaque psoriasis were selected for this case–control study at Alexandria Main University Hospital from December 2022 to January 2024. Clinical evaluation of the patients was achieved through the calculation of the Psoriasis Area and Severity Index score. Serum IL-15 levels were measured by enzyme linked immunosorbent assay. The Mann–Whitney test was employed for abnormally distributed quantitative variables. The Spearman coefficient test was applied for comparisons of two abnormally distributed quantitative variables. Results: The mean serum IL-15 Level in the patient group (482.90 ng/mL [Q1 = 440.63, Q3 = 525.16]) was significantly higher than that in the control group (410.25 ng/mL [Q1 = 310.23, Q3 = 430.35]) ( P < 0.001). Furthermore, the serum IL-15 level had a significant positive correlation with the Psoriasis Area and Severity Index score ( P = 0.049). Conclusion: The level of IL-15 may indicate the severity of disease in the patients with psoriasis, and IL-15 has the potential to be a clinical biomarker and therapeutic target of psoriasis, which needs more in-depth studies to further clarify.