Serum paraoxonase-1 as a marker of oxidative stress and pulmonary dysfunction in sarcoidosis: association with disease activity and prognostic potential.

Objectives: Sarcoidosis is a multisystem granulomatous disorder characterized by an oxidative imbalance and inflammatory activation. Paraoxonase-1 (PON1) is a high-density lipoprotein-associated antioxidant enzyme that plays a protective role against oxidative stress. This study aimed to evaluate the serum PON1 activity in patients with sarcoidosis, its relationship with disease stage, and its association with pulmonary function and routine biochemical parameters. Materials and methods: A total of 45 patients with sarcoidosis and 45 age- and sex-matched healthy controls were included. Complete blood counts, biochemical parameters, and pulmonary function test results were evaluated. Serum PON1 activity was colorimetrically determined using a commercial kit. Statistical analyses included correlation, logistic regression, receiver operating characteristic (ROC) curves, and partial least squares discriminant analysis (PLS-DA). Results: Serum PON1 activity was significantly lower in patients with sarcoidosis than in the healthy controls (p<0.001). PON1 levels showed strong positive correlations with FEV Conclusion: Serum paraoxonase activity is markedly reduced in sarcoidosis and is correlated with disease severity and pulmonary dysfunction, suggesting increased oxidative stress. Although not an independent predictor, PON1 may serve as a useful adjunctive biomarker, particularly for evaluating disease severity in Stage II and advanced stages, rather than for early diagnosis.