However, the expression of Nox2 in PMN-MDSCs of BPD cases was obviously lower than non-BPD cases (P < 0.05) (Figure 3(a)), indicating that PMN-MDSCs have a certain immunosuppressive function in BPD children and the defect was manifested in the low expression of Nox2. This evidence concerns the gene CYBB and bronchopulmonary dysplasia.