Comparison of CD163+CD206+M2 Macrophages in the Lesional Skin of Bullous Pemphigoid and Pemphigus Vulgaris: The Possible Pathogenesis of Bullous Pemphigoid

Background: M2 macrophages play a critical role in the induction of T helper 2 (Th2) polarization. Methods: To investigate the contribution of M2 macrophages to the pathogenesis of bullous pemphigoid (BP) and pemphigus vulgaris (PV), we employed immunohistochemical staining for CD163 and CD206, as well as pSTAT1, pSTAT6, interleukin (IL)-4, IL-13, CCL17, CCL18 and Foxp3 in the lesional skin of 10 cases of BP and PV. Results: The numbers of CD163+ CD206+ M2 macrophages were higher in BP than in PV. Moreover, pSTAT6+ cells, CCL17+ cells, CCL18+ cells and Foxp3+ regulatory T cells were prominent only in the lesional skin of BP. To further investigate the function of M2 macrophages, we examined the mRNA expression and production of Th2-related chemokines from M2 macrophages in vitro, which showed a significant increase in the mRNA expression and production of CCL18 when stimulated by IL-4 or IL-13. Conclusion: Our study sheds light onto one of the possible immunological mechanisms of BP and PV. (C) 2014 S. Karger AG, Basel