A. Representative IHC image of an orthotopically implanted syngeneic tracheal graft (STG) and adjacent host trachea. B. Immunohistochemistry against CD68 (a~e), iNOS (f~j), and CD206 (k~o) cells in native control and STG at post-op 1wk, 2wk, 1 mos, 6 mos and 1 y were performed on serial sections to characterize macrophages, M1 macrophages and M2 macrophages, respectively. Representative positive staining of macrophages is highlighted by arrowheads. Scale bar=10 μm. C. Data was represented as CD68+ (a), iNOS+ (b), CD206+ (c) macrophages per mm2 of the graft and the ratio of macrophage phenotype M1 (iNOS+)/ M2 (CD206+) (d) in the graft. (n=3; ANOVA with Tukey’s test; * p<0.05; Error bars represents the standard deviation)