Homing-Associated Cell Adhesion Molecule (H-CAM/CD44) on Human CD34⁺ Hematopoietic Progenitor Cells

Abstract

Human CD34⁺ hematopoietic progenitor cells (HPCs) express CD44 and can directly adhere to hyaluronate (HA) via CD44. Furthermore, CD44 may also be involved in the regulation of CD34⁺ HPC proliferation and development. The expression of CD44 molecules on CD34⁺ hematopoietic progenitor cells is significantly lower on bone marrow (BM) CD34⁺ cells compared with circulating CD34⁺ cells in cord blood and peripheral blood. Myeloid and erythroid progenitor cells are found predominantly in CD34⁺CD44^- cell fractions. More interestingly, CD34⁺CD44⁺ cells expressing B-lymphocyte-associated CD10 and CD19 would represent unique B-lymphocyte committed precursors in the BM, which might undergo apoptotic cell death in the early steps of B-cell differentiation.

Key Words:

• CD44
• Hematopoetic progenitor cells
• Hematopoiesis
• Apoptosis