CD8A and chronic obstructive pulmonary disease: Conversely, HLA-DQ protein levels on blood CD3+CD8+ Tc cells were lower in both the COPD-only group (1320 ± 585 MFI) and the ACO group (1468 ± 740 MFI) compared to the HS group (2892 ± 3216 MFI, Figure 2C and Figure 3C).