Adhesion molecule expression on CD34+ progenitor cells from normal and aplastic anaemia bone marrow.

Aplastic anaemia (AA) is a disease of bone marrow failure. Evidence has been produced for both a stem cell and a stromal cell defect in this disease. The contribution of deficient or defective cell adhesion molecules (CAMs) has not been determined. CAMs have been shown to be important in stem cell-stromal cell interactions and maintenance of haemopoiesis. In this study the expression of CAMs (LFA-1, LFA-3, ICAM-1. VLA-4, CD44, sLex and L-selectin) on CD34+ progenitor cells from 10 normal donors and eight patients with AA was investigated using double immunofluorescence. There was no significant difference in the percentage of CD34+ cells that were CAM+ between normal and AA bone marrow, suggesting that abnormal CAM expression on AA progenitor cells is not responsible for nor contributes to the pathogenesis of the disease. However, these findings do not exclude abnormal CAM function on progenitor cells, or abnormal expression or function of CAM ligands or counter-receptors on AA stromal cells.