T cells around bronchioles in human pulmonary GVHD are positive for pERK and B cells are positive for phosphorylated AKT (pAKT). Representative images of tissue samples from human patients with pulmonary GVHD. (A) Images of specimens from patient #1 stained with H&E or EVG. BO (upper right) and perivenulitis (lower left) were present. (B-D) Images of samples from patient #1 captured by imaging mass cytometry: (B) CD4, CD8, CD20, and CD68; (C) pERK and pAKT; (D) merged images of CD4/pERK, CD8/pERK, and CD20/pAKT. (E) Images of specimens from patient #2 stained with H&E or EVG. The area enclosed by the square was analyzed by imaging mass cytometry. (F-H) Images from patient #2 captured by imaging mass cytometry: (F) CD4, CD8, CD20, and CD68; (G) pERK and pAKT; (H) merged images of CD4/pERK, CD8/pERK, and CD20/pAKT. (I) Proportions of pERK-positive CD4⁺ and CD8⁺ cells, and pAKT-positive CD20⁺ cells (n = 7). pAKT, phosphorylated AKT; pERK, phosphorylated ERK.