CD4 and bronchopulmonary dysplasia: The findings illustrated that BPD patients exhibited a greater infiltration level of monocytes, macrophages M0, neutrophils, naive CD4+ T cell, and lower levels of dendritic cells activated, macrophages M2, resting memory CD4 T cells, and CD8 T cells (Figure 2B), pointing to immune system changes as a potential root cause of BPD.