There was no significant difference in the down-regulation of HMOX1 and IFN-activated STAT1 and Bach1, as well as the up-regulation of TGFB. 42Bach1 is a transcriptional repressor that may be essential for limiting the M2 phenotype, and its deficiency worsens some forms of pulmonary alveolar proteinosis (PAP). This evidence concerns the gene HMOX1 and pulmonary alveolar proteinosis.