Differential expression of macrophage antigens in periapical lesions: a potential role for macrophage polarization

Background and aimPeriapical lesions are considered as the most common lesions that associated with necrotic teeth. Histopathologically, these lesions are accompanied with variable amount of inflammatory cells; among them, macrophages are present in a significant number. This study was planned to assess the role of macrophage subpopulations in the pathogenesis of periapical lesions through the presence of M1 and M2 macrophages.Materials and methodTwenty cases of periapical lesions including radicular cysts and periapical granuloma (10 cases each) were selected. Immunohistochemical expressions of CD68, CD163, CD204 and pancytokeratin were evaluated.ResultsM1 macrophages (CD68+ and CD204+) were strongly associated with periapical granuloma. In radicular cyst, the total number of macrophages was lower than that in periapical granuloma and they were M2 macrophages (CD163+).ConclusionMacrophages contributed to the inflammatory response of periapical lesions. M1 macrophages were associated with periapical granuloma while M2 macrophages were associated with radicular cyst. Transformation of periapical granuloma to radicular cysts requires M2 macrophage polarization.