S100A8 and Autoimmunity: Macrophage polarization and M1/M2 balance play an important role in anti-microbial defense, asthma and allergy, fibrosis, wound healing, and autoimmunity.26 To validate the existence of two different macrophages, immunofluorescence staining of CD68, S100A8, and CD163 was performed (Fig. 3j).