CHI3L1 and tuberculosis: Next, we focused on the cell types contained in the niche based on the NMF analysis (Fig. 2A) and verified colocalization of CHI3L1+ and C1Qhi macrophages together with aberrant basaloid cells, TB-SC, and SFTPB+-ciliated cells in IPF tissue sections (Fig. 4, A to D, and fig.