CD4 and chronic obstructive pulmonary disease: The transcriptomic analysis further revealed that macrophages, CD4+ T, CD8+ T, γδ T, NK, and proli.T cells exhibited higher expression of the ligand gene MIF, and macrophages showed elevated expression of receptor genes CCR1, CCR5, FPR1, and FPR3 in COPD compared to HS (Figure 7G).