Studies have found that pulmonary infections in MM patients after chemotherapy may be caused by the stimulation of bone marrow stroma, inducing the expression of Interleukin-6 (IL-6) and vascular endothelial growth factor, which obstruct the generation of polyclonal antibody pathways, lower the CD4+/CD8+ ratio, and reduce the bioactivity of dendritic cells, thereby disrupting the immune microenvironment and increasing the risk of pulmonary infection.14 This evidence concerns the gene CD4 and Miyoshi myopathy.