Fig. 3.

Quantification of total basal cells and KRT5⁺ and KRT14⁺ basal cell subpopulations in the healthy human lung. Cells were counted according to their positivity for p63, KRT5 or KRT14 immunostaining in conducting airways (1 donor, 2 samples, n = 7 assessed fields/sample) and in distal airways (5 donors, 1-3 samples/donor, n = 34 assessed bronchioles). Data are expressed as mean ± SEM. A 2-Way ANOVA with Bonferroni post-test revealed a significant interaction according to the type of airway (Conducting versus distal, p < 0.0001); all 6 quantified populations were significantly different between conducting and distal airways (***p < 0.001). Each dataset (conducting and distal) was then compared separately with a One-Way ANOVA test: ***p < 0.001 versus “Conducting KRT5⁺”, ^### p < 0.001 versus “Distal KRT5⁺”