Peripheral memory T‐cell profile is modified in patients undergoing periodontal management

AIMS T-cells are known to have a role in periodontitis, however, the effect of periodontal therapy on peripheral memory T-cells is unclear. This study evaluated variation in peripheral memory T-cells and red complex bacteria in sub-gingival plaque in patients undergoing periodontal management. METHODS Peripheral blood mononuclear cells and sub-gingival plaque were collected from 54 periodontitis patients at baseline, 3-, 6- and 12-months post-therapy and 40 healthy controls. Periodontitis patients were divided into treatment outcome (TxO) groups based on prevalence of sites with probing depth ≥5mm as good ( 20%) at study conclusion. Naive (TN - CCR7+ CD45RA+ ), central memory (TCM - CCR7+ CD45RA- ), effector memory (TEM - CCR7- CD45RA- ) and effector memory T-cells re-expressing CD45RA (TEMRA - CCR7- CD45RA+ ) were phenotyped using flow cytometry in CD4+ , CD8+ , CD4+ CD8+ and CD4- CD8- T-cells and red complex bacteria were quantified using qPCR. RESULTS At baseline, periodontitis subjects had significantly greater mean probing depths and P. gingivalis proportions, lower TN but higher CD4+ TCM , CD8+ TCM , CD4+ CD8+ TEM , and CD4- CD8- TEM cell proportions compared to health. Periodontal therapy decreased mean probing depths, P. gingivalis proportions, TEM and CD4+ and CD8+ TCM cells, but increased TN and CD4+ and CD8+ TEMRA cells. The T-cell profile in the good TxO group showed therapy-related changes in CD4+ TEM , and CD8+ TN and TEM cells, whereas, no changes were observed in the poor TxO group. CONCLUSION Management and the reduction in red complex bacteria were associated with changes in peripheral memory T-cells in periodontitis.