SERUM BIOMARKERS IN DIFFERENT TYPES OF PULMONARY FIBROSIS

Idiopathic pulmonary fibrosis (IPF) is a chronic progressive interstitial lung disease of unknown origin with an average life expectancy of 3-5 years after diagnosis. The disease is accompanied by progressive pulmonary fibrosis, decreased lung function, poor response to therapy and early mortality. Various biomarkers, including serum biomarkers, are used for timely and differential diagnosis of idiopathic pulmonary fibrosis (IPF) and COVID-19-associated pulmonary fibrosis (PF), predicting the course of the disease and assessing the effectiveness of specific therapy. Target was to investigate the features of pulmonary fibrosis based on serum biomarkers in patients with ILF and COVID-19-associated fibrosis. Methods. Changes in serum concentrations of biomarkers CA15-3, LOXL2, TGFBR3 and periostin in patients with ILF (n=10), COVID-19-associated pulmonary fibrosis and controls were investigated. Results. Significant differences were found between LOXL2 concentrations in the control and ILF groups (p=0.003), ILF and COVID-19-associated fibrosis groups (p=0.036) and between periostin concentrations in the control and ILF groups (p=0.042). ROC analysis for LOXL2 revealed: in the ILF and control groups AUC=0.854 (95% CI 0.693-1.0; p<0.0001), with a sensitivity of 80.0% and specificity of 76.9%; in the ILF and COVID-19-associated LF groups AUC=0.773 (95% CI 0.556-0.989; p=0.014) with a sensitivity of 99.0% and specificity of 63.6%. For periostin: AUC=0.692 (95% CI 0.469-0.916; p=0.092) with a sensitivity of 50.0% and specificity of 84.6%. Correlation analysis in the pooled group showed a significant correlation for CA15-3 and periostin (rs=0.383; 95% CI 0.042-0.645; p=0.025), LOXL2 and periostin (rs=0.509; 95% CI 0.196-0.727; p=0.002), TGFBR3 and CA15-3 (rs=0.347; 95% CI 0.0-0.62; p=0.044). Conclusions. We found significant differences between serum levels of LOXL2 in ILF group and CG, ILF group and COVID-19-associated LF. ROC analysis yielded the values of the optimal points of group separation by serum LOXL2 and periostin levels. This allows differential diagnosis of different pulmonary fibrosis.