Association of skin microbiome with interleukin-17F and interleukin-33 in patients with plaque psoriasis

Background Psoriasis is a chronic inflammatory skin disorder associated with immune dysregulation and alterations in the skin microbiome. Interleukin-17F (IL-17F) and interleukin-33 (IL-33) are key cytokines involved in psoriasis, yet their relationship with microbiome changes and genetic polymorphisms remains unclear. Objective To investigate variations in the skin microbiome in plaque psoriasis patients and correlate these with serum levels and genetic polymorphisms of IL-17F and IL-33. Patients and methods In this case–control study, 80 participants (40 psoriasis patients and 40 healthy controls) were enrolled in the Dermatology Clinic at Benha University. Skin microbiome analysis was conducted alongside measurements of serum IL-17F and IL-33 levels using enzyme-linked immunosorbent assay. Genetic polymorphisms of IL-17A (rs2275913) and IL-33 (rs1929992) were analyzed. Disease severity was assessed using Psoriasis Area and Severity Index. Results Psoriasis patients exhibited significantly higher fungal and bacterial growth compared to controls (75 vs. 17.5%, P <0.001) and elevated serum levels of IL-17F and IL-33 ( P <0.001). Fungal and mixed bacterial–fungal growth was positively associated with higher IL-17 and IL-33 levels ( P <0.001). Genetic analysis revealed significant associations of IL-17A GA and AA genotypes and IL-33 CT and TT genotypes with psoriasis ( P <0.001). IL-17 and IL-33 levels correlated positively with Psoriasis Area and Severity Index scores ( P <0.001). Receiver operating characteristic analysis identified IL-17 as a strong diagnostic marker (area under the curve: 0.935) compared to IL-33 (area under the curve: 0.748). Conclusion This study establishes a significant association between IL-17F and IL-33 levels, skin microbiome alterations, and genetic polymorphisms in plaque psoriasis. These findings highlight their potential as biomarkers for disease severity and therapeutic targets in psoriasis management.