In cases where CXCL8-suppressive isolates were detected, their incidences in plaque were calculated to range from approximately 3–47 % of the total cultivable microbial load; with mean incidences of 16.9, 20.2 and 17.6 % detected for healthy supragingival, gingivitis supragingival and subgingival plaque, respectively. Here, CXCL8 is linked to gingivitis.