PRDX-4: a novel biomarker similar to KL-6 for predicting the occurrence and progression of systemic sclerosis-ILD.

AIM: Lungs are among the most affected organs in systemic sclerosis (SSc), with interstitial lung disease (ILD) being a leading cause of mortality. Biomarkers are increasingly explored for predicting SSc-ILD detection and progression. This study evaluates the roles of Krebs von den Lungen-6 (KL-6), surfactant protein D (SP-D), and peroxiredoxin-4 (PRDX-4) in diagnosing SSc-ILD and monitoring progression.

METHODS

A total of 89 individuals (61 SSc patients and 28 healthy volunteers) were included. SSc patients were grouped based on pulmonary function tests and high-resolution computed tomography findings to determine SSc-ILD presence. Patients with SSc-ILD were further categorized by progressive pulmonary fibrosis (PPF) presence based on 2022 guidelines. Serum KL-6, SP-D, and PRDX-4 levels were measured using the Enzyme-Linked Immuno-Sorbent Assay method.

RESULTS

Of the 61 SSc patients, 34 (55.7%) had ILD. Serum KL-6 and PRDX-4 levels were significantly higher in SSc-ILD patients (p = 0.004 and p = 0.012, respectively). KL-6, SP-D, and PRDX-4 levels were elevated in the PPF group compared to stable disease (p = 0.001). PRDX-4 showed the highest diagnostic performance for PPF (AUC: 0.936, sensitivity: 85.7%, specificity: 85%).

CONCLUSION

KL-6 is a well-established biomarker for SSc-ILD, but PRDX-4 offers superior diagnostic accuracy, especially in identifying PPF.