Comparative Cytokine Profiles in Enthesitis-Related Arthritis and Adult Spondyloarthritis

To compare circulating cytokine/chemokine profiles in treatment-naïve enthesitis-related arthritis (ERA) and adult peripheral spondyloarthritis (SpA) to identify shared and divergent biological signatures.

In a combined cross-sectional/longitudinal design conducted at a tertiary center (January 2024-January 2025), the authors evaluated ERA (n = 30) and adult SpA patients (n = 30) alongside age-/sex-matched healthy pediatric (n = 20) and adult (n = 20) controls. Clinical features, disease activity, and routine laboratory parameters were recorded. Serum TNF-α, IL-17A, IL-22, GM-CSF, CXCL4/PF4, CXCL10, CXCL16, and NRG4 were quantified by ELISA.

ERA showed more peripheral arthritis (83.3%) and enthesitis (90%), whereas adult SpA showed more sacroiliitis/axial involvement (93.3%) and longer morning stiffness. Versus controls, both patient groups had elevated CXCL16 (p <0.001) and PF4 (p = 0.001). GM-CSF and NRG4 were increased in both diseases and were higher in adult SpA than ERA (GM-CSF: 65 vs. 38 pg/mL, p = 0.003; NRG4: 50.23 vs. 37.34 ng/mL, p <0.001). TNF-α, IL-17A, IL-22, and CXCL10 showed no significant group differences.

These findings provide a rationale for biomarker-informed phenotyping and future stratified treatment approaches; however, single-center sampling and ELISA-only measurements warrant multicenter validation.