Right-shifted histograms of GCF samples stained with anti-CD177- and isotype antibody. Neutrophils from peripheral blood and GCF from periodontitis patients (n = 13) were stained with anti-CD177 and isotype antibody and analysed by flow-cytometry. (A) Histograms of neutrophil CD177 expression in blood and GCF (from one patient out of 13). (B) Histograms of isotype staining in blood and GCF from the same patient.