Lymphocytes subcluster into T cells, B cells, plasma cells, and mast cells. (A) Uniform Manifold Approximation and Projection (UMAP) visualization of intragraft lymphocytes subclustered into T cells, B cells, plasma cells, and mast cells. (B) Violin plot of cell type–defining markers: CD3E for T cells, TPSAB1 (tryptase) for mast cells, MS4A1 (CD20) for B cells, and SDC1 (CD138) for plasma cells. (C) UMAP visualization of lymphocytes according to donor or recipient origin, and (D) rejecting or nonrejecting biopsies.