F2R and chronic obstructive pulmonary disease: The magnification of panel g1 and h1 demonstrates low immunoreactivity for anti-PAR-1 H111 Ab (green) in the cell membrane, and the red fluorescence of anti-ATAP2 Ab is localized in both the cell membrane and cytoplasm of epithelial cells of central airways with COPD, mainly in the apical pole of columnar cells.