Similar Individual Serum Levels of MCP-1, TNF-α, and IL-6 From Periodontitis Patients Before and 1 Year After...

Treatment of periodontitis may lower the inflammation status as measured in sera from patients. To investigate this in a biological assay, we co-cultured periodontal ligament fibroblasts (PDLFs) from a healthy donor and peripheral blood mononuclear cells (PBMCs) as a source for osteoclasts. PDLFs were primed for 3 days with serum from periodontitis patients before and from 1 year after successful treatment of periodontitis (n = 13). After priming, PBMCs were added. No significant differences in the number of osteoclasts that formed after 3 weeks were found between baseline and after-treatment serum priming. To find an explanation, we analysed the serum composition on the presence of inflammatory, pro-osteoclastogenic cytokines. We found no differences between before and after treatment for cytokines MCP-1, TNF-α, and IL-6. Interestingly, these levels of cytokines at baseline and after treatment strongly correlated per individual (correlation p-value between p = 0.03 and p < 0.0001, correlation r² between 0.37 and 0.89). Strikingly, between each other, MCP-1, TNF-α, and IL-6 did not correlate. These results show that over the 1-year time frame a cytokine equilibrium, the relatively similar levels of cytokines over a longer period, exists that is unique per individual. This suggests that the immune system is a constant for these cytokines, adapted to the needs of the individual. Larger cohorts, the inclusion of healthy individuals and longer time intervals need to be studied to further establish the true magnitude of these intriguing findings.