Human Megakaryocytes III. Characterization in Myeloproliferative Disorders

• Published in: Blood Vol. 63; no. 3; pp. 615 - 622
• Main Authors: Rabellino, Enrique M., Levene, Richard B., Nachman, Ralph L., Leung, Lawrence L.K.
• Format: Journal Article
• Language: English
• Published: Washington, DC Elsevier Inc 01-03-1984; The Americain Society of Hematology
• Subjects: Antigens - immunology; Biological and medical sciences; Bone Marrow - pathology; Factor VIII - immunology; Fluorescent Antibody Technique; Glycoproteins - immunology; Hematologic and hematopoietic diseases; Humans; Leukemias. Malignant lymphomas. Malignant reticulosis. Myelofibrosis; Medical sciences; Megakaryocytes - analysis; Megakaryocytes - metabolism; Megakaryocytes - pathology; Membrane Proteins - immunology; Myeloproliferative Disorders - blood; Myeloproliferative Disorders - immunology; Myeloproliferative Disorders - pathology; Platelet Count; Platelet Membrane Glycoproteins; Receptors, Fc - immunology; Megakaryocyte; Chronic myelocytic leukemia
• ISSN: 0006-4971; 1528-0020
• DOI: 10.1182/blood.V63.3.615.615

Abnormal proliferation of the megakaryocytic line was observed in the marrow tissue from patients with myeloproliferative disorders. Megakaryocytes were identified by immunofluorescence using distinct platelet protein markers. Plasma factor VIII antigen (factor VIII:AGN) and platelet glycoproteins IIb and IIIa were detected in normal mature and early megakaryocytes, as well as in a morphologically heterogeneous population of low density marrow cells regarded as atypical megakaryocytes. Atypical megakaryocytes were defined as oval/round 14–35-μm diameter blast-like mononuclear/multinucleated cells bearing platelet protein markers with distinct morphological features, including cytoplasmic vacuolation, variable nuclear/cytoplasmic ratios, and variable cytoplasmic granulation. Atypical megakaryocytes were observed in most chronic myelogenous leukemia (CML) patients and in two patients with polycythemia vera, representing between 60 and 1,840 cells/104 cells (< 1.050 g Percoll/cu cm). No atypical megakaryocytes were found in (a) 20 normal controls, (b) two patients with essential thrombocythemia, (c) a patient with thrombocytosis secondary to acute bleeding, and (d) in two patients with CML. Atypical megakaryocytes appear to represent a single-cell population, as demonstrated by a series of double immunofluorescence assays using combinations of five different antiplatelet protein sera. There was a statistically significant correlation between the frequency of atypical megakaryocytes and the presence of immature forms of myeloid cells in blood. Analyses of Fc IgG receptors conducted with two different immunofluorescence systems have demonstrated that phenotypic similarities existed between atypical megakaryocytes and myeloproliferative platelets. Analyses of platelet proteins and differentiation markers on megakaryocytes are useful in elucidating the pathophysiologic alterations occurring in the megakaryocytic compartment in patients with myeloproliferative disorders.