Carbohydrate antigen 15.3 as a serum biomarker of interstitial lung disease in systemic sclerosis patients

Abstract Background To determine the usefulness of Ca 15.3 as a candidate biomarker in systemic sclerosis (SSc) patients with interstitial lung disease (ILD). Methods Two-hundred-twenty-one SSc patients with Ca 15.3 determinations were considered; 168 had evidence of interstitial lung involvement on high-resolution computed tomography (HRCT); digitalized scans were available for scoring in 84 subjects. Discrimination between patients with or without ILD, was assessed by receiving operating characteristics (ROC) analysis; correlations between HRCT scores and Ca 15.3 were performed. Survival and serial pulmonary function tasting (PFT) data were used for prognostication. Results Ca 15.3 serum levels strongly correlated with HRCT scores (r = 0.734, p  − 4 ). Ca 15.3 had an area under ROC to detect the meaningful 20% fibrosis extent equal to 0.927 and abnormal Ca 15.3 values were capable of differentiating between patients at hi- or low-risk for progression in the group with undetermined disease extent (HR = 3.209, confidence interval [CI 95 ] = 1.56–6.602, p = 0.002). Ca 15.3 outperformed other PFT measures in providing a separation of survival estimates where HRCT scans are unavailable. The combined use of HRCT scores and Ca 15.3 in SSc–ILD patients was more discriminatory (HR = 4.824, CI 95  = 2.612–8.912, p  95  = 1.703–4.147, p  Conclusion Ca 15.3 is a rapid and inexpensive candidate biomarker for SSc–ILD being proportional to the extent of lung injury and specific and sensitive in assessing meaningful extents of the disease with prognostic significance.