# Biomarkers of Inflammation and Radiographic Progression in Axial Spondyloarthritis: A Clinical Evaluation of Leptin, Adiponectin, TNF-α, and IL-17A

## TL;DR

This study explores how leptin and adiponectin relate to inflammation and disease progression in axial spondyloarthritis, suggesting they could be useful biomarkers.

## Contribution

The study identifies leptin and adiponectin as potential biomarkers for disease activity and structural damage in axial spondyloarthritis.

## Key findings

- Leptin levels correlate with disease activity, inflammation, and radiographic progression in axSpA.
- Adiponectin shows inverse associations with disease activity and structural damage, indicating protective properties.
- TNF-α and IL-17A have limited correlations with structural changes compared to leptin and adiponectin.

## Abstract

Background/Objectives: Axial spondyloarthritis (axSpA) is a chronic immune-mediated inflammatory disorder affecting the spine and sacroiliac joints, with variable clinical expression. This study assessed serum levels of inflammatory (TNF-α, IL-17A) and metabolic (leptin, adiponectin) biomarkers and their associations with disease activity, inflammation, structural damage, and comorbidities. Methods: This prospective cross-sectional study assessed 89 axSpA patients using clinical, laboratory, and radiological evaluations. Disease activity was measured using ASDAS-CRP and BASDAI scores. Radiographic damage was quantified using the Modified Stoke Ankylosing Spondylitis Spine Score (mSASSS). Serum concentrations of TNF-α, IL-17A, leptin, and adiponectin were quantified by enzyme-linked immunosorbent assay (ELISA). Clinical and imaging correlations were analyzed. Results: Serum leptin levels correlated significantly with higher disease activity scores, inflammatory markers (CRP, ESR), radiographic progression (syndesmophyte formation, mSASSS), and arterial hypertension. Adiponectin levels were inversely associated with disease activity, structural damage, and arterial hypertension, suggesting anti-inflammatory, bone- and cardio-protective properties. TNF-α levels showed an association with inflammatory markers and were higher in patients with peripheral enthesitis. IL-17A levels were weakly correlated with disease activity and structural severity and were significantly lower in patients with a history of anterior uveitis. Conclusions: Leptin and adiponectin may serve as complementary biomarkers in axSpA, reflecting both inflammatory burden and structural damage. While TNF-α and IL-17A remain key therapeutic targets, their correlation with structural changes appears limited. Biomarker profiling could support personalized disease monitoring. Longitudinal studies are needed to validate prognostic implications.