CD8A and Patent ductus arteriosus: Later, when we analyzed his tumor together with the other PDA tumors from the neoadjuvant and adjuvant vaccine research, we found that the lymphoid aggregates formed in his surgically resected PDA showed an immune suppressive signature, which was characterized by a relatively high density of Foxp3+ cells, albeit high density of CD8+ cells and relatively high expression of CTLA-4.