Original of Flt3 ligand in bone marrow and peripheral blood of aplastic anemia and its means

Objective To determine the levels of FL(Flt3 ligand) in the bone marrow and peripheral blood of patients with aplastic anemia(AA) and to trace the cell excreting FL. Methods ELISA assay was applied to determine the levels of FL in bone marrow and peripheral blood. Single or double staining immunofluorescence assay and flow cytometry were used to trace the FL producing cell and the expression of its receptor. The effect of cyclosporine A on FL producing when the T lymphocytes were cocultured with PHA was also investigated. Results The levels of FL in the bone marrow and peripheral blood of AA increased significantly and was about 25 times as high as the controls. Statistic analysis showed that there was no difference between the levels of bone marrow and the levels of peripheral blood. Flow cytometry showed that there are large quantity FL inside of CD3 + cells, otherwise CD3 + from AA patients expressed FL on its membrane and there was almost no FL inside the cells. Lymphocytes secreted FL when they were cocultured with PHA and CyA that inhibited FL production. Conclusion The levels of FL in bone marrow and peripheral blood significantly increased as the result of secretion from CD3 positive cells.