Association Between Inflammatory Cytokines and Systemic Inflammation Indices in Patients With Psoriasis: A Cross‐Sectional Study

ABSTRACT Background and Objectives Systemic inflammation indices derived from complete blood counts (CBC) are accessible markers of inflammatory burden, but their relationship with circulating cytokines in psoriasis remains unclear. We investigated associations between CBC‐derived indices and serum cytokines in psoriasis. Materials and Methods In this cross‐sectional study, we included 28 patients with psoriasis and 23 healthy controls. Serum IL‐17, IL‐22, IL‐23, IL‐31, IL‐33, IL‐36, TNF‐α, TGF‐β, and IFNγ were quantified by ELISA. CBC‐derived indices were computed (neutrophil‐to‐lymphocyte ratio (NLR), platelet‐to‐lymphocyte ratio (PLR), systemic immune‐inflammation index (SII), systemic inflammation response index (SIRI), and pan‐immune‐inflammation value (PIV). Case–control comparisons used the full sample. Cytokine–index associations were evaluated in psoriasis patients using bivariate correlations and multivariate GLM adjusted for age, smoking, and NAFLD. Multiplicity was controlled using Benjamini–Hochberg false discovery rate (BH‐FDR); prespecified sensitivity analyses used log‐transformed cytokines and Spearman correlations. Results Psoriasis patients had higher levels of all cytokines (all p < 0.001) and higher SIRI versus controls (p < 0.001; q = 0.005). PIV showed a nominal case–control difference (p = 0.022) that did not remain significant after BH‐FDR (q = 0.055), while NLR, PLR, and SII did not differ. In adjusted multivariate GLM, TGF‐β showed a global association with the joint set of indices (Pillai's trace = 0.295; p = 0.039) that did not survive BH‐FDR (q = 0.507) and was attenuated with log‐transformation. Nominal univariate effects for TNF‐α on SIRI (F = 4.600; p = 0.039) and PIV (F = 5.660; p = 0.023) did not remain significant after BH‐FDR. Conclusions SIRI was consistently elevated in psoriasis, whereas PIV showed a nominal difference versus controls. Across exploratory analyses, SIRI and PIV showed the most consistent directional co‐variation with cytokines, but associations were modest. These findings are hypothesis‐generating and support further validation in larger cohorts to determine whether CBC‐derived indices can serve as scalable adjunct markers of inflammatory activity in psoriasis.