CD4 and chronic myelogenous leukemia, BCR-ABL1 positive: Antibodies to three T cells markers (CD3, CD4 and CD8 [7]) and one B cell marker (CD20) [7] were applied to serial CML bone marrow sections to test for the expected strong overlap between T cell markers (e.g. CD3 and CD8) but for a minor overlap between T and B cell markers (e.g. CD3 and CD20).