EMP2 and tuberculosis: In the TB model group, most of the downregulated DE genes were related to cell structural proteins and cell functional proteins, and the functional proteins of alveolar epithelial cells account for a large proportion, such as Sftpc, Sftpb, Sftpd, Sftpa1, Mgp, Wfdc2, Sec1413, Postn, Cldn5, Aqp5, Emp2, Foxf1, and so forth.