Fig. 1

Lung lymphoid follicles, B cells, BAFF⁺ and Ki67⁺ B cells were increased in CF patients. a Representative confocal images of triple-color immunofluorescence staining of representative pulmonary lymphoid follicles (LFs) from subjects with CF (top panels) and normal controls (Ctrl, bottom panels). B cells are identified by staining with red fluorophore for CD20. BAFF is identified by staining with green fluorophore. Ki67 positive cells have a gray color. 4′6-diamidino-2-phenylindole (blue) was used to counterstain the nuclei. The final panel in each row is a merged file of CD20, BAFF and Ki67 staining. In the CF images (top row), the magnification is 20X. In the control images (bottom row), the magnification is 60X. However, for the control images digital zooming was used to better visualize the CD20⁺ cells. The images shown are representative of LFs in CF subjects (n = 27) and normal controls (n = 10). b Representative low power images of lung tissue from a subject with CF (left panel) and normal control (right panel). Lymphoid follicles are identified by staining with red fluorophore for CD20. 4′6-diamidino-2-phenylindole (blue) was used to counterstain the nuclei