Th17 cells contribute to periodontal tissue destruction by secreting which cytokine that recruits neutrophils?

• A. IL-17
• B. IL-2
• C. IL-4
• D. IL-10

Answer: (A)

Th17 cells steer neutrophil recruitment through a specific pro-inflammatory cytokine they secrete. This cytokine acts on gingival epithelial and stromal cells to induce chemokines that attract neutrophils, such as CXCL1, CXCL2, and CXCL8 (IL-8), and also promotes production of growth factors that increase neutrophil numbers. The influx and activation of neutrophils then release proteolytic enzymes and reactive oxygen species, contributing to tissue destruction in periodontal disease. The other cytokines listed don’t directly drive neutrophil recruitment in this context: IL-2 mainly supports T cell proliferation, IL-4 shifts toward a Th2 response, and IL-10 dampens inflammation.