CD4 and Patent ductus arteriosus: The results showed that the percentages of CD8+ T cells (PDA-PBMC vs. C-PBMC: 34.28±0.8431% vs. 30.94±0.8405%), CD4+ T cells (PDA-PBMC vs. C-PBMC: 54.51±0.9725% vs. 57.17±0.6233%) and Tregs (PDA-PBMC vs. C-PBMC: 5.755±0.145% vs. 5.772±0.2105%) in PBMCs were not markedly different between PDA patients and healthy volunteers (Figure 1D).