Altered BM architecture in tissues from patients with hematologic diseases. BM whole-mount specimens from patients with hematopoietic disorders were fluorescently stained with cell lineage–specific antibodies and DAPI (nuclei). (A) SAA: most of the hematopoietic space is occupied by adipocytes (green) closely surrounded by almost overlapping vascular (CD34, red) and stromal (CD146, white) network. (B) Same image as in panel A but only the CD146⁺ staining to clearly display the stromal cell meshwork. (C) AML: both normal and malignant myeloid cells, recognized by anti-CD33 Ab, appear in clusters (green); in addition, an increased number of CD34⁺ cells (red) appear in close proximity to the endothelial matrix (red). (D) CML-blast crisis: CD34⁺ leukemic blasts (red) occupy the BM. (E) Multiple myeloma: massive numbers of irregularly shaped malignant CD38⁺ cells (red), forming a large nodule. (F) T large granular lymphocyte leukemia: sparsely distributed CD8⁺ cells (white), along with CD3⁺ cells (red) and sporadic CD20⁺ B cells (green). Scale bars are in micrometers. Related images appear in supplemental Videos 8 and 9.