Figure 1

Flow cytometry plots of B cells and memory B cells in peripheral blood. A representative example of the difference in percentage of CD20⁺ B cells between COPD (blue curve) and healthy (red curve) and the CD20⁺CD27⁺ gate to analyze the memory B cells is depicted in the upper panel. The CD27⁺IgM^- gate for class switched memory B cells, the CD27⁺IgM⁺ gate for IgM⁺ memory B cells, and the CD27^-IgM⁺ gate for naive B cells are shown for a current and a never smoker in the lower panel.