Expression of the CDll /CD18, Leukocyte Adhesion Molecule 1, and CD44 Adhesion Molecules During Normal Myeloid and Erythroid Differentiation in Humans

We have used three-color flow cytometry to investigate the pattern of expression of the CDI 1 lCD18, CD44. and leukocyte adhesion molecule 1 (LAM-1) adhesion molecules during myeloid and erythroid differentiation in humans. The earliest myeloid cells, identified as CD33'"CD15-, were exclusively CD44hi but contained both leukocyte function-associated antigen 1 (LFA-1 hi) and LFA-1'" cells, as well as LAM-1' and LAM-1cells. This CD33'"CD15myeloid subpopulation expressed only low levels of CDI 1 c and failed to express CD11 b, CD14, or any lymphoid (CD3, CD16, CD19) antigens or glycophorin. Commitment to monocyte differentiation, suggested by the presence of an LFA-lhi CDI IC+ subset within the CD33'"CDI 5subpopulation, was clearly signaled by upregulation of CD33; these monocyte-lineage committed cells were exclusively CD33hi, CDUhi, CDllahi, CDllc', and exhibited a broad range of intensity of CDI 5 expression. Later stages of monopoiesis were identified by acquisition of CDI 1 b, and subsequently of CD14. Myeloid cells committed to granulopoiesis re-