CD8A and chronic obstructive pulmonary disease: Methods. The whole Tc subsets, including Tc1/2/10/17, CD8+ regulatory T cells (Tregs) and CD8+α7+ T cells, were quantified by flow cytometry in peripheral blood from 24 stable COPD subjects (SCOPD), 14 patients during acute exacerbations (AECOPD), and 14 healthy nonsmokers (HN).