IL17A and periodontitis: Different subsets produce distinct cytokine profiles: Th1 (IFN‐γ) promote cell‐mediated immunity against intracellular pathogens; Th2 (IL‐4, IL‐5, and IL‐13) support humoral immunity and antihelminth responses; and Th17 (IL‐17 and IL‐22) are crucial for mucosal defense against fungi and extracellular bacteria but are strongly implicated in inflammatory tissue destruction (e.g., bone loss) in periodontitis [33].