Immunocytochemical identification of cells of megakaryocytic lineage by alkaline phosphatase anti-alkaline phosphatase method.

proliferative disorders. It is necessary to accurately identify the megakaryocytic cells in order to diagnose megakaryocytic leukemia and to assess the significance of the pres ence of such cells in the circulating blood . At present, megakaryocytes and their precursors can be best identified either by ultrastructural study of platelet peroxidase or by immunocytochemical studies using monoclonal antibodies specific for platelet glycoprotein (Gp) IIb/IIIa complex or for factor VIII. There is a need to develop simple, practical, methods to facilitate accurate identification of the megakaryocytes and their precursor cells. We have obtained a specific monoclonal antibody (HPI-1D) to platelet Gp (IIb/IIIa)2,3 from Drs. C. Y. Li and W. L. Nichols of the Mayo Clinic, USA and have successfully used this antibody and an alkaline phosphatase anti-alkaline phosphatase (APAAP) method to identify cells of megakaryocytic lineage.