Association of Interleukin-4 and matrix metalloproteinase-9 with bacterial profile in patients with chronic periodontitis

Background: Periodontitis (PO) is a multifactorial disease with diverse etiology. Of course the bacteria are the principle cause of the disease. But the host factors, predominantly the immune response, play an important function in defense of patients against these bacteria. Objective The aim of the study was to assess the interrelation between interleukin-4 (IL-4), matrix metalloproteinase-9 (MMP-9) and bacterial profiles in chronic periodontitis patients. Methods: A total of 65 patients with chronic PO and 25 age and sex matched apparently healthy individuals as controls were enrolled in the study. Blood was drawn from all participants. Serum IL-4 and MMP-9 were detected. Patients’ plaque samples were taken and bacterial profiles determined by standard microbiology procedures. Results: The median levels of anti-inflammatory-IL-4 and MMP-9 for patients were 17.5 pg / ml, 1.3 pwhilst they were reported with an average of 29.06 and 0.53 for the controls, respectively with P-values being highly significant. The most frequent pathogen was Strep tococcus pyogenes (17 cases, 26.15%) followed by Staphylococcus aureus (10 patients, 15.38%), Streptococcus mutans (9 patients, 13.85%), Enterococci faecalis (7 cases, 10.77%) and Streptococcus salivarius (6 cases, 9.23%). Streptococcus pseudoporcinus was associated with the highest IL-4 level (40.88 pg/ml), differing significantly from all other bacteria. Streptococcus pyogenes, Streptococcus mutans, and Enterococcus faecalis showed comparable IL-4 levels (19.51, 19.18, and 20 pg/ml, respectively), differing significantly from other species. Conclusion: Chronic periodontitis is associated with decreased serum levels of IL-4 and increased levels of MMP-9. Gram-positive bacteria are predominant and may be responsible for most cases of chronic PO.