IL4 and dental pulp disorder: Furthermore, through evaluation of the tissue expression of IL-4, IL-12, and IFN-γ, Fraga and colleagues found that the IFN-γ protein expression was increased in radicular cysts.48 IFN-γ belongs to the family of T helper (Th) 1-like cytokines and is intimately connected with the M1 polarization of macrophages.17 These findings implied the active participation of M1 macrophages in tissue damage and inflammatory progress.