Flow cytometry evaluation of erythroid dysplasia in patients with myelodysplastic syndrome

Erythroid dysplasia is the pathologic hallmark of myelodysplastic syndromes (MDS). To develop a quantitative flow-cytometry approach to its evaluation, we analyzed the expression of CD71, CD105, cytosolic H-ferritin (HF), cytosolic L-ferritin (LF) and mitochondrial ferritin (MtF) in erythroblasts from 104 MDS patients, 69 pathologic control patients and 19 healthy subjects. Six-parameter, 4-color flow cytometry was employed, and data were expressed as mean fluorescence intensity. Compared with pathologic and healthy controls, MDS patients had higher expression of HF (P < 0.001) and CD105 (P < 0.001), and lower expression of CD71 (P < 0.001). MtF was specifically detected in MDS with ringed sideroblasts, and there was a close relationship between its expression and Prussian blue staining (r = 0.89, P < 0.001). In vitro cultures of myelodysplastic hematopoietic progenitors showed that both HF and MtF were expressed at a very early stage of erythroid differentiation, and that MtF expression is specifically related to mitochondrial iron loading. A classification function based on expression levels of HF, CD71 and CD105 allowed us to correctly classify > 95% of MDS patients. This flow-cytometry approach provides an accurate quantitative evaluation of erythroid dysplasia and allows a reliable diagnosis of sideroblastic anemia, and may therefore be a useful tool in the work-up of patients with MDS.

Flow cytometry evaluation of erythroid and myeloid dysplasia in patients with myelodysplastic syndrome

The purpose of this study was to develop a flow cytometric approach to the evaluation of marrow dysplasia in myelodysplastic syndromes (MDS). We first studied a cohort of 103 MDS patients as well as 46 pathological and healthy controls. Flow cytometry data were expressed as percentage of positive cells. Analysis of erythroid cells showed higher proportions of immature cells (P < 0.001) and decreased levels of CD71 expression on nucleated red cells (P = 0.02) in MDS. Analysis of myeloid cells showed lower proportions of CD10+ and higher proportions of CD56+ granulocytes (P < 0.001), and increased ratios of immature to mature cells (P = 0.007). Since no single immunophenotype could accurately differentiate MDS from other conditions, we used discriminant analysis for generating erythroid and myeloid classification functions using combinations of immunophenotypic parameters. These functions were prospectively validated in a testing cohort of 69 MDS patients and 46 pathological controls. A diagnosis of MDS was obtained in 60/69 cases (87%). No false-positive results were noticed among controls. Significant correlations between values of these functions and both degree of morphological dysplasia and the International Prognostic Scoring System were found. These findings indicate that flow cytometry evaluation of marrow dysplasia is feasible and may be useful in the work-up of individual MDS patients.

Reduced-intensity conditioning regimen with thiotepa and fludarabine followed by allogeneic blood stem cell transplantation in haematological malignancies

The aim of this study was to investigate thiotepa (TT) and fludarabine (Fluda) as a preparative regimen for allogeneic peripheral stem cell transplant in patients not eligible for a standard myeloablative regimen due to comorbidities and/or poor performance status. TT was given at a dose of 10 mg/kg over 2 days and Fluda at 125 mg/m(2) over 5 days. In all, 21 patients (14 male, seven female; 10 acute leukaemia, eight myelodysplastic syndrome, two non-Hodgkin's lymphoma, one Hodgkin's disease) were treated. The median age was 51 years (range 30-55 years). All patients achieved full donor-type chimaerism. Adverse events included mild nausea and vomiting in two patients and a slight increase of serum amylase in three. A total of 13 patients received RBC transfusions (median 6 U, range 1-23), and all received platelets (median 4 U, range 1-27). Four patients died of nonrelapse causes and five of relapse. The 1-year probabilities of transplant-related mortality and relapse were 19 and 29%, respectively. In total, 12 patients remain in complete remission (median follow-up: 786 days). The 3-year overall survival probability was 58%. We conclude that this regimen is feasible and well tolerated.

Blood stem cell collections in multiple myeloma: definition of a scoring system

The purpose of the study was to identify factors that could predict good yields of peripheral blood stem cells (PBSC) in multiple myeloma (MM). Fifty-one MM patients, nine with refractory disease and 42 in plateau phase, were mobilized with high-dose cyclophosphamide (HD-Cy) at 4 g/m2 followed by granulocyte colony-stimulating factor (G-CSF) 5 microg/kg/day. Clinical and laboratory parameters at the time of mobilization were analyzed for correlations with the number of CD34+ cells collected, with the colony-forming unit granulocyte-macrophage (CFU-GM) count, and the mononuclear cell (MNC) count. In univariate analysis, low WBC count, low platelet count, prior exposure to melphalan, and an interval >6 months from the start of treatment correlated with poor yields of CD34+ cells. Low platelet count, prior exposure to melphalan or to radiotherapy, and an interval >6 months from the start of treatment were associated with a low CFU-GM count. On the basis of these data, we defined a scoring system able to predict the yield of the mobilizing procedure. According to this system, the presence of more than one risk factor (low WBC and platelet counts, prior exposure to melphalan, interval from first chemotherapy >6 months) was predictive of insufficient collections when a conventional combination of mobilizing measures are used.

Immunophenotypic changes of fetal cord blood hematopoietic progenitor cells during gestation

We measured cell surface expression of CD34, HLA-DR, CD38, CD19, CD33, CD71, and CD45 antigens in the hematopoietic progenitor cells of fetal cord blood to investigate immunophenotypic changes at different gestational ages. These antigens were identified by flow cytometry in 11 fetuses (gestational age 19-24 wk, in 12 preterm (25-28 wk) and in ten newborn infants born at term. The frequency and number of CD34+ cells were higher in the blood of the 11 fetuses; in addition, a statistically significant inverse correlation between number of CD34+ cells and advancing gestational age was noted. The numbers of CD34+ CD19+, CD34+ CD33+, and CD34+ CD45+ coexpressing cells were significantly higher in the fetuses, whereas CD34+ CD38+ cells were more represented in the neonates at term. Gestational age was inversely correlated with the number of CD34+ CD19+ and CD34+ CD33+ coexpressing cells. A positive correlation between gestational age and CD34+ CD38+ cells was noted. The number of CD34- CD19+, CD34- CD38+, and CD34- CD45+ cells was higher in term infants; furthermore, a significant correlation between advancing gestational age and CD34- CD38+ or CD34- CD45+ cells was demonstrated. The proliferative capacity was also higher at lower gestational ages. These data suggest that the development and lineage commitment of fetal cord blood hematopoietic progenitor cells are very active during the last two trimesters of pregnancy. The most significant changes of hematopoietic cells maturation seem to occur within 25 wk of gestation.

Trisomy 11 and a complex t(11;11;22) in a patient with acute myelomonocytic leukemia (AML-M4) following myelodysplasia (MDS): a cytogenetic study of a mechanism of leukemogenesis

We describe a 73-year-old man diagnosed with acute myelomonocytic leukemia (AML-M4) following myelodysplasia with trisomy 11 and with a t(11;11;22). This is the first case with both abnormalities present in the same cells and with the t(11;11;22) involving a chromosome 11 already duplicated at 11q23. This band contains the MLL gene that undergoes partial tandem duplication in patients with +11, which is "promiscuous," being translocated with a large number of genetic partners. Our patient had a complex karyotype that was completely defined by in situ hybridization. This technique demonstrated that the t(11;11;22) derivative with a duplication of band 11q23 carried from three to four copies of MLL. Two copies of the gene were close to each other and centromeric to the break-point region. Therefore, a partial tandem duplication of the MLL gene might have happened before the occurrence of t(11;11;22). Considering the associated chromosome defects, the monosomy for the long arm of chromosome 7, due to an unbalanced translocation t(7;17), further underlines the possibility that a partial tandem duplication of the MLL gene might have taken place.