CEACAM8 and cystic fibrosis: Confirming the PCA results, Mann-Whitney analysis revealed that proportions of total neutrophils (median CF.U vs controls, 31.31 vs 1.81% of CD45+ cells, FDRp=0.0001) and all subsets of neutrophils (identified based on the expression of CD16 and CD66b activation markers) were elevated in CF.U compared with age-matched controls (figure 2D,E).