Loss of Endoreduplication as Morphogenesis of Micromegakaryocytes in Myelodysplastic Syndrome.

Morphogenesis of micromegakaryocytes in MDS was investigated in a case of refractory anemia with excess of blasts by analysing megakaryocyte colonies developed from peripheral blood mononuclear cells in a semi-solid culture containing aplastic anemia patient\u27s plasma as source for megakaryocyte colony stimulating factor and thrombopoiesis stimulationg factor. Candidate megakaryocyte colonies were individually stained for glycoprotein (GP)IIb/IIIa by immunocytochemical method. Three types of colonies were distinguished ; type I composed of 10-30 large magakaryocytes with high ploidy number, type II composed of 50-200 micromegakaryocytes with single nucleus, and type III composed of 20-50 micromegakaryocytes. Type I colonies were similar to megakaryocyte colonies obtained from three control subjects. Periodic in situ observation of type II and III colonies disclosed that large megakaryocytes never appeared during 21 days\u27 culture, suggesting mitotic growth at every generation. These findings indicate that loss of endoreduplication is primary defect in micromegakaryocyte formation by MDS clone. Quantitaive aspect of platelet formation by micromegakaryocytes could not be assessed in this study, but morphological observation in situ or on GPIIb/IIIa-stained preparation suggested reduced platelet production. Biological significance of diminished endoreduplication is yet to be determined in respect to leukemic predisposition

Low Dose Cytosine Arabinoside Regimen for Overt Leukemia, Hypoplastic Leukemia and Myelodysplastic Syndromes : Hypoplastic Leukemia Responds Best.

In a series of 38 patients consisting of 13 with overt acute leukemia, 14 with hypoplastic leukemia, and 11 with myelodysplastic asyndromes (MDS), responsiveness to low dose cytosine arabinoside (LDAC) regimen was investigated to clarify the disease type most benefitted. LDAC was continuously administered intravenously at dose 0.2mg/kg/day and continued as long as possible to meet the pre-assigned target point of 5% marrow blasts which was confirmed by weekly marrow aspiration. Overall response rate was 47%; complete remission (CR) being 31% and partial remission (PR) 16%. CR rate was significantly different between the disease types ; 69% in hypoplastic leukemia, 23% in overt leukemia and 0% in MDS (p=0.01). In hypoplastic leukemia the survival time was significantly longer in the LDAC-treated cases compared with 15 historical control cases treated with supportive care only ; median survial being 750 days in the former and 250 days in the latter (p=0.01). In overt leukemia only three M2 AML cases obtained CR ; two of them were treated during hypoplastic phase induced by intensive chemotherapy. All CR cases eventually achieved the target point after 20 to 42 days (median 26) of LDAC administration. Substantial toxicity of LDAC was evident, but most cases tolerated well. The present investigation suggests that hypoplastic leukemia is the disease type most sensitive to LDAC regimen. Stratification of the elderly leukemia patients should be considered for this regimen

In Vitro Study of the Independent and Combined Effects of Recombinant Human GM-CSF and G-CSF on Normal Bone Marrow Granulocytes : GM-CSF Enhances the Growth Effect but Suppresses the Terminal Maturation-inducing Effect of G-CSF

We studied the independent and combined effects of recombinant human granulocyte colony- stimularting factor (rhG-CSF) and recombinant human granulocyte-macrophage colony-stimulating factor (rhGM-CSF) on the growth and maturation of neutrophilic granulocytes. Absolute granulocyte numbers, cellular composition, and neutrophil alkailne phosphatase (NAP) activity were examined after normal nonphagocytic bone marrow cells were cultured for seven days with rhG-CSF, rhGM-CSF, and a combination of both growth factors. The numbers of band and segmented forms produced in the cultures containing rhGM-CSF were significantly lower than in control cultures or those with rhG-CSF. When both rhGM-CSF and rhG-CSF were in the culture total granulocyte production was highest, but the increment of band and segmented forms produced by rhG-CSF alone was reduced. Neutrophil alkaline phosphatase (NAP), an enzyme marking terminal maturation, was increased by rhG-CSF alone, but not by rhGM-CSF alone. Cultures containing both CSFs showed significantly lowered NAP activity compared to those containing rhG-CSF alone. The decrement in NAP activity was proportionate to the amount of rhGM-CSF added. These results indicate that terminal maturation-inducing effect is a property of rhG-CSF but not of rhGM-CSF. In the presence of both GM-CSF and G-CSF, the growth of granulocytes is maximumly stimulated but the terminal maturation-inducing effect of rhG-CSF is suppressed

Erratum to: Expression of myeloperoxidase and gene mutations in AML patients with normal karyotype: double CEBPA mutations are associated with high percentage of MPO positivity in leukemic blasts

Erratum to: International Journal of Hematology, 94(1), pp.81-89: 2011DOI 10.1007/s12185-011-0883-yThe original version of this article unfortunately contained some errors in Table 2 in the column headed ‘‘Amino acid changes’’. The corrected table is given here

Diagnosis of acute myeloid leukemia according to the WHO classification in the Japan Adult Leukemia Study Group AML-97 protocol

We reviewed and categorized 638 of 809 patients who were registered in the Japan Adult Leukemia Study Group acute myeloid leukemia (AML)-97 protocol using morphological means. Patients with the M3 subtype were excluded from the study group. According to the WHO classification, 171 patients (26.8%) had AML with recurrent genetic abnormalities, 133 (20.8%) had AML with multilineage dysplasia (MLD), 331 (51.9%) had AML not otherwise categorized, and 3 (0.5%) had acute leukemia of ambiguous lineage. The platelet count was higher and the rate of myeloperoxidase (MPO)-positive blasts was lower in AML with MLD than in the other WHO categories. The outcome was significantly better in patients with high (≥50%) than with low (<50%) ratios of MPO-positive blasts (P < 0.01). The 5-year survival rates for patients with favorable, intermediate, and adverse karyotypes were 63.4, 39.1, and 0.0%, respectively, and 35.5% for those with 11q23 abnormalities (P < 0.0001). Overall survival (OS) did not significantly differ between nine patients with t(9;11) and 23 with other 11q23 abnormalities (P = 0.22). Our results confirmed that the cytogenetic profile, MLD phenotype, and MPO-positivity of blasts are associated with survival in patients with AML, and showed that each category had the characteristics of the WHO classification such as incidence, clinical features, and OS

Expression of myeloperoxidase and gene mutations in AML patients with normal karyotype: double CEBPA mutations are associated with high percentage of MPO positivity in leukemic blasts.

The percentage of myeloperoxidase (MPO)-positive blast cells is a simple and highly significant prognostic factor in AML patients. It has been reported that the high MPO group (MPO-H), in which >50% of blasts are MPO activity positive, is associated with favorable karyotypes, while the low MPO group (≤50% of blasts are MPO activity positive, MPO-L) is associated with adverse karyotypes. The MPO-H group shows better survival even when restricted to patients belonging to the intermediate chromosomal risk group or those with a normal karyotype. It has recently been shown that genotypes defined by the mutational status of NPM1, FLT3, and CEBPA are associated with treatment outcome in patients with cytogenetically normal AML. In this study, we aimed to evaluate the relationship between MPO positivity and gene mutations found in normal karyotypes. Sixty AML patients with normal karyotypes were included in this study. Blast cell MPO positivity was assessed in bone marrow smears stained for MPO. Associated genetic lesions (the NPM1, FLT3-ITD, and CEBPA mutations) were studied using nucleotide sequencing. Thirty-two patients were in the MPO-L group, and 28 patients in the MPO-H group. FLT3-ITD was found in 11 patients (18.3%), NPM1 mutations were found in 19 patients (31.7%), and CEBPA mutations were found in 11 patients (18.3%). In patients with CEBPA mutations, the carrying two simultaneous mutations (CEBPA (double-mut)) was associated with high MPO expression, while the mutant NPM1 without FLT3-ITD genotype was not associated with MPO activity. Both higher MPO expression and the CEBPA (double-mut) genotype appeared to be associated with improved overall survival after intensive chemotherapy. Further studies are required to determine the importance of blast MPO activity as a prognostic factor, especially in CEBPA wild-type patients with a normal karyotype