Generally, Th1 cell‐derived cytokines, such as interferon‐γ (IFN‐γ) and interleukin‐12 (IL‐12), are associated with postinfection tissue destruction in periodontitis, while Th2 cell‐derived cytokines, such as IL‐4, have been thought to be protective factors for the repair of bone loss (Queiroz‐Junior et al., 2010; Repeke et al., 2011). The gene discussed is IL4; the disease is periodontitis.