The expression levels of HLA-DR proteins on blood CD14+CD163+ M2a monocytes (Figure 2A and Figure 3A) were significantly elevated in the COPD-only group (7695 ± 3743 MFI) compared to the HS group (5391 ± 3153 MFI, adjusted p = 0.026) and the asthma group (4716 ± 1679 MFI, adjusted p = 0.012). Here, CD163 is linked to chronic obstructive pulmonary disease.