What is the role of Th17 cells in the pathogenesis of periodontal disease?

• A. They produce antibodies neutralizing bacteria.
• B. They primarily regulate lymph node architecture without affecting periodontium.
• C. They suppress osteoclast activity to prevent bone loss.
• D. They secrete IL-17 which promotes neutrophil recruitment and inflammatory responses that contribute to tissue destruction.

Answer: (D)

Th17 cells drive a neutrophil-dominated inflammatory response in the periodontium by secreting IL-17. This cytokine stimulates resident cells in the gum tissue to produce chemokines and other proinflammatory mediators that recruit neutrophils and amplify inflammation. The resulting sustained inflammatory environment leads to tissue destruction and, importantly, promotes osteoclast activation and bone loss via RANKL upregulation. So, the best answer captures that Th17-derived IL-17 promotes neutrophil recruitment and inflammatory cascades that contribute to periodontal tissue damage. Antibody production is a B cell function, and Th17 cells are not primarily about organizing lymph node architecture without affecting the periodontium; they actively drive local inflammation and bone resorption, and they do not suppress osteoclasts.