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

Abstract 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 ≥5 mm as good (<10% of sites), moderate (10–20%) or poor (>20%) at study conclusion. Naïve (T N —CCR7 + CD45RA + ), central memory (T CM —CCR7 + CD45RA − ), effector memory (T EM —CCR7 − CD45RA − ) and effector memory T‐cells re‐expressing CD45RA (T EMRA —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 Porphyromonas gingivalis proportions, lower T N but higher CD4 + T CM , CD8 + T CM , CD4 + CD8 + T EM and CD4 − CD8 − T EM cell proportions compared to health. Periodontal therapy decreased mean probing depths, P . gingivalis proportions, T EM and CD4 + and CD8 + T CM cells, but increased T N and CD4 + and CD8 + T EMRA cells. The T‐cell profile in the good TxO group showed therapy‐related changes in CD4 + T EM , and CD8 + T N and T EM 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.