acid-phosphatase and Leukemia--Megakaryoblastic--Acute

We present a case of acute megakaryoblastic leukemia identified by electron microscopy and platelet-specific antibodies. The histological examination of bone marrow showed distinct myelofibrosis. In accordance with recent communications, low-dose cytosine arabinoside treatment (20 mg twice daily s.c. over 21 days) was initiated. The subsequent bone marrow examination showed a severe hypoplasia with persistent blasts. Amsacrine and VP-16 were given without success. Finally the patient died of septicemia without proof of pathogen uninfluenced by antibiotic and antiseptic therapy 6 weeks after diagnosis. Our case report confirms the poor prognosis of acute megakaryoblastic leukemia.

Topics: Acid Phosphatase; Aged; Amsacrine; Antineoplastic Combined Chemotherapy Protocols; Bone Marrow; Cytarabine; Etoposide; Humans; Leukemia, Megakaryoblastic, Acute; Male; Neoplasm Proteins; Neoplastic Stem Cells; Primary Myelofibrosis

Acute megakaryoblastic leukemia (AMKL) has two peaks in distribution of incidence (in adults and children 1 to 2 years of age) and is frequently seen in children with Down syndrome. The current study was undertaken to disclose whether there were any differences between these groups.. Electron microscopic and ultrastructural cytochemical features of 49 children and adults with a AMKL or chronic myelogenous leukemia (CML) in megakaryoblastic crisis were compared.. Blast cells from children with AMKL, including those with and without Down syndrome, had immature features lacking typical alpha granules and a demarcation membrane system (DMS). However, blast cells from patients with AMKL with Down syndrome had more theta, electron-lucent, and basophil-like granules, suggesting that the blast cells had more potential to differentiate into other cell lines than megakaryocytes. The AMKL blast cells of adult patients showed a higher percentage of platelet peroxidase (PPO) positivity than other subgroups, and they occasionally contained typical alpha granules and DMS. This indicated that the blast cells of adults with AMKL were more mature than those of children and CML in megakaryoblastic crisis.. By electron microscopic analysis, leukemic megakaryoblasts differed between children with AMKL with and without Down syndrome, adults with AMKL, and patients with CML in megakaryoblastic crisis.

Topics: Acid Phosphatase; Adolescent; Adult; Age Factors; Aged; Blast Crisis; Blood Platelets; Child; Child, Preschool; Cytoplasmic Granules; Down Syndrome; Histocytochemistry; Humans; Infant; Intracellular Membranes; Leukemia, Megakaryoblastic, Acute; Leukemia, Myelogenous, Chronic, BCR-ABL Positive; Megakaryocytes; Microscopy, Electron; Middle Aged; Peroxidase; Peroxidases

A cytochemical study using: Sudan black B; alpha-naphthyl acetate (ANAE) staining; estimation of alpha-naphthyl butyrate (ANBE) esterase activity; acid phosphatase activity; and 5' nucleotidase activity was carried out in 15 cases of megakaryoblastic leukaemia. These included cases of M7 acute myeloid leukaemia and blast crises of chronic granulocytic leukaemia. The megakaryoblastic nature of the blasts was first established using two monoclonal antibodies against platelet glycoproteins, and by estimating the platelet/peroxidase reaction at ultrastructural level. Our findings suggest that megakaryoblasts have a typical cytochemical profile comprising positive ANAE staining and acid phosphatase activity with a predominant localisation in the Golgi zone and negative or weak ANBE activity. A similar positive cytochemical pattern was also found in five cases of erythroleukaemia (M6). The specificity of the 5'nucleotidase activity for megakaryoblasts was not confirmed. In most cases of megakaryoblastic leukaemia there was no 5'nucleotidase activity only two cases showed positive reactions--reactions were positive in several cases of myeloblastic and lymphoblastic leukaemia. We suggest that cytochemical methods may be useful in diagnosing M6 and M7 acute leukaemia because less than 40% of leukaemic cells react with specific monoclonal antibodies.

Topics: 5'-Nucleotidase; Acid Phosphatase; Adult; Aged; Antibodies, Monoclonal; Antigens, Surface; Carboxylic Ester Hydrolases; Humans; Leukemia, Megakaryoblastic, Acute; Male; Megakaryocytes; Middle Aged; Nucleotidases