Immuno-, lectin-, and enzyme-histochemical characterization of human bone marrow endothelium.

"Homing" of hematopoietic progenitor cells to the bone marrow occurs during the clinical practice of bone marrow transplantation. Its mechanism is unknown, although adhesive interactions between hematopoietic cells and sinusoidal endothelium in the bone marrow may be implicated. Studies of human bone marrow endothelial cells have previously been limited by the lack of markers for these cells. In this report, we describe positive staining of bone marrow endothelial cells from human bone marrow trephine biopsies with antibody to factor VIII-related antigen (FVIIIR-Ag) (Dako, High Wycombe, UK), the plant lectin Ulex europaeus agglutinin-I (UEA-I), and two mouse monoclonal antibodies, BMA120 and QBEND/10. In addition, alkaline phosphatase could be demonstrated in the majority of marrow endothelial cells using a novel enzyme histochemical technique. These studies defined the marker profile of human marrow endothelium. The results of this study will facilitate the isolation and culture of human marrow endothelial cells for in vitro studies of their roles in hematopoietic stem cell homing.