Purpose: To explore in myeloperoxidase anti-neutrophil cytoplasmic antibody-positive anti-neutrophil cytoplasmic antibody-associated vasculitis (MPO-AAV) the value of circulating oncomarkers in identifying interstitial lung disease (ILD) and predicting prognosis.
Methods: Newly diagnosed MPO-AAV patients were recruited retrospectively at a single center. The serum levels of carbohydrate antigen (CA) 19-9, CA125, cytokeratin fraction 21-1 (CYFRA21-1), carcinoembryonic antigen, squamous cell carcinoma antigen and neuron-specific enolase were compared between patients with and without ILD. The strength of the oncomarkers in identifying ILD was assessed through logistic regression and receiver operating characteristic (ROC) curves. Correlation analysis was applied to detect the associations between oncomarkers and ILD severity. The significance of serum oncomarkers as prognosis predictors for MPO-AAV associated ILD was evaluated by survival analysis.
Results: 169 MPO-AAV patients were included and ILD was found in 101 patients. Serum CA125, CA19-9 and CYFRA21-1 were significantly higher in patients with ILD than those without ILD. The area under the ROC curve of CA19-9, CA125, and CYFRA21-1 for identifying ILD was 0.701, 0.660, and 0.711, respectively. A specificity of 98.5% for diagnosing ILD was found for CA19-9 at the recommended normal level. CA19-9 was positively correlated with HRCT fibrosis score (r = 0.498, p < 0.001) and CYFRA21-1 was correlated with ground-glass score (r = 0.316, p = 0.002). Both CA19-9 and CYFRA21-1 were independent risk factors for all-cause mortality in patients with ILD.
Conclusion: Serum CA19-9 and CYFRA21-1 maybe useful markers in the diagnosis, disease severity evaluation and prognosis prediction of MPO-AAV associated ILD.