ARG1 and pulmonary fibrosis: Previous studies have found that ARG1 is a biomarker of M2 macrophages.[37] In the macrophages of the lung tissue of idiopathic pulmonary fibrosis patients, the expression of ARG1 is higher than that of the lung tissue of healthy controls.[37] The microarray results of this study showed that ARG1 in CTD-ILD group was significantly higher than in CTD group, and analysis of differential lincRNAs and adjacent differential mRNAs (< 300 kb) revealed that T311354 was correlated with ARG1.