CD56 Expression Is an Important Prognostic Factor in Multiple Myeloma Even with Bortezomib Induction.

OBJECTIVES: In this retrospective study, we evaluated the impact of CD56, CD117, and CD28 expression on clinical characteristics and survival in newly diagnosed myeloma patients treated with bortezomib-based induction therapy. METHODS: We analyzed 110 myeloma patients. Immunophenotype was determined using panels consisting of CD19/CD38/CD45/CD56/CD138 and CD20, CD28, and CD117 were used additionally. All samples were tested for recurrent chromosomal aberrations. RESULTS: CD56, CD117, and CD28 expression rates were 71, 6, and 68%, respectively. The lack of CD56 expression was associated with light chain myeloma. The lack of CD117 expression was associated with elevated creatinine levels (p = 0.037). We discovered the correlation between CD 28 expression and female gender. The median progression-free survival (PFS) for patients with revised International Staging System stage 2 disease with CD56 expression or the lack of CD56 expression was 20.5 vs. 13.8 months (p = 0.03). In patients undergoing autologous hematopoietic stem cell transplantation (aHSCT), we found no difference in PFS and overall survival regarding the CD56 expression. We found no impact of CD117 and CD28 expression on PFS in patients regarding aHSCT. CONCLUSIONS: Induction treatment incorporating bortezomib diminishes the negative impact of the lack of CD117 expression and aberrancy of CD28 but does not overcome the negative impact of the lack of CD56 expression.

Mobilization with cyclophosphamide reduces the number of lymphocyte subpopulations in the leukapheresis product and delays their reconstitution after autologous hematopoietic stem cell transplantation in patients with multiple myeloma.

BACKGROUND: Autologous hematopoietic stem cell transplantation is considered the standard of care for younger patients with multiple myeloma. Several mobilization regimens are currently used, most commonly growth factors alone or in combination with chemotherapy. The aim of our study was to investigate the differences in lymphocyte subpopulation counts between three different mobilization regimens on collection day, in the leukapheresis product and on day 15 after autologous hematopoietic stem cell transplantation. PATIENTS AND METHODS: In total 48 patients were prospectively enrolled in three different mobilization regimens; (i) filgrastim (20), (ii) pegfilgrastim (19) and (iii) cyclophosphamide + filgrastim (9). Lymphocytes, CD16+/56+ natural killer and CD4+/CD25high T regulatory cells were determined by flow cytometry. RESULTS: We found a statistically significant difference between the mobilization regimens. Cyclophosphamide reduced lymphocyte and natural killer (NK) cell counts on collection day (lymphocytes 1.08 × 109/L; NK cells 0.07 × 109/L) compared to filgrastim (lymphocytes 3.08 × 109/L; NK cells 0.52 × 109/L) and pegfilgrastim (lymphocytes 3 × 109/L; NK cells 0.42 × 109/L). As a consequence lymphocyte and NK cell counts were also lower in the leukapheresis products following cyclophosphamide mobilization regimen (lymphocytes 50.1 × 109/L; NK cells 4.18 × 109/L) compared to filgrastim (lymphocytes 112 × 109/L; NK cells 17.5 × 109/L) and pegfilgrastim (lymphocytes 112 × 109/L; NK cells 14.3 × 109/L). In all mobilization regimens T regulatory cells increased 2-fold on collection day, regarding the base line value before mobilization. There was no difference in T regulatory cell counts between the regimens. CONCLUSIONS: Mobilization with cyclophophamide reduces the number of mobilized and collected lymphocytes and NK cells as compared to mobilization with growth factors only and results in their delayed reconstitution following autologous hematopoietic stem cell transplantation. We found no difference between filgrastim and pegfilgrastim mobilization.

RUNX1 amplification in lineage conversion of childhood B-cell acute lymphoblastic leukemia to acute myelogenous leukemia.

Amplification of RUNX1 (alias AML1) is a recurrent karyotypic abnormality in childhood acute lymphoblastic leukemia (ALL) that is generally associated with a poor outcome. It does not occur with other primary chromosomal abnormalities in acute ALL. AML1 amplification in acute myelogenous leukemia (AML) is a rare secondary event described mainly in therapy-related cases. AML1 amplification was found in a 13-year-old patient with AML M4/M5 leukemia that occurred 5 years after she had been diagnosed with common B-cell ALL. Conventional cytogenetic, fluorescent in situ hybridization (FISH), and polymerase chain reaction methods revealed no other chromosomal change expected to occur in a disease that we assumed to be a secondary leukemia. Due to the lack of cytogenetic data from the diagnostic sample, we developed a new approach to analyze the archived bone marrow smear, which had been stained previously with May-Grünwald-Geimsa by the FISH method. This analysis confirmed that in addition to t(12;21), AML1 amplification and overexpression existed already at the time the diagnosis was made. The chromosomal changes, however, were found in different clones of bone marrow cells. While the first course of chemotherapy successfully eradicated the cell line with the t(12;21), the second cell line with AML1 amplification remained latent during the time of complete remission and reappeared with a different immunophenotype.

Filgrastim-alone versus pegylated filgrastim-alone for autologous peripheral blood stem cells mobilization in newly diagnosed multiple myeloma patients.

BACKGROUND: Autologous hematopoietic stem cell transplantation (aHSCT) is the recommended standard upfront treatment for transplant eligible myeloma patients. Considering possible complications related to chemotherapy-cytokine mobilization, cytokine-alone mobilization is often used. We compared mobilization with filgrastim alone to pegfilgrastim alone in newly diagnosed myeloma patients after induction treatment with bortezomib and dexamethasone. The comparison was made between peripheral blood stem cell (PBSC) yields, number of apheresis, hematopoietic stem cell subsets, and time to neutrophil and platelet engraftment after aHSCT. METHODS: A total of 42 myeloma patients were prospectively enrolled in the study: 21 received filgrastim, 21 pegfilgrastim. Flow cytometry was used to determine the number of PBSC, myeloid, lymphoid, and megakaryocyte precursors in peripheral blood and apheresis product on day 1 of apheresis. RESULTS: The median number of collected PBSC was 5.05 × 106/kg in the filgrastim and 4.66 × 106/kg in the pegfilgrastim group (p = 0.428). The median number of apheresis was 2.5 in the filgrastim and 2 in the pegfilgrastim group (p = 0.901). The number of megakaryocyte precursors in peripheral blood was significantly higher in the filgrastim group, but not in the apheresis products. There were no statistically significant differences in the myeloid and lymphoid precursors in the peripheral blood and in the apheresis products. The median time to neutrophil and platelet engraftment was 13 days and 16.5 days for filgrastim and 13 days and 16 days for pegfilgrastim group. CONCLUSIONS: We can conclude that pegfilgrastim alone is at least equally successful as filgrastim alone for the PBSC mobilization in newly diagnosed myeloma patients.

Reticulocyte analysis using light microscopy and two different flow cytometric procedures.

The reticulocyte count is a clinically important indirect indicator of erythropoietic activity of the bone marrow. Reticulocyte enumeration by light microscopy is rather inaccurate and has poor reproducibility. Automation of the reticulocyte count by means of flow cytometry has considerably improved the quality of this investigation.In our study, we compared three methods of establishing the blood reticulocyte number: the microscopic brilliant cresyl blue method and two flow cytometric procedures using thiazole orange (TO), namely FACSort (Becton-Dickinson) and EPICS Profile (Coulter). The aims of the study were (1) to select the most suitable TO concentration to be used with the EPICS Profile cytometer, (2) to determine the correlation between the microscopic method and the two flow cytometric procedures, and (3) to appraise the suitability of flow cytometry for reticulocyte analysis in routine clinical work.According to our results, the most appropriate TO concentration for the EPICS Profile counter is 0.1 mg/L . We observed a good correlation between the three methods tested; the correlation coefficients ranged from 0.82 to 0.87. The mean intra-assay coefficients of variation for the microscopic method and the EPICS Profile and FACSort procedures were 27.5%, 8.4% and 6.3%, respectively.

Selective apoptosis of multiple myeloma cells in primary samples induced by arsenic trioxide.

OBJECTIVES: Currently, multiple myeloma (MM) is an incurable disease. Despite the fact that arsenic trioxide (ATO) shows promising results in vitro, data from treatment of patients with MM are disappointing. Due to these discrepancies, we compared the efficacy and selectivity of ATO at two different concentrations in samples from MM patients. METHODS: The extent of apoptosis induced by 2 and 5 µM ATO was evaluated by flow cytometry using annexin V. 34 diagnostic bone marrow samples obtained from MM patients were analysed. RESULTS: 5 µM ATO efficiently induced apoptosis in primary samples. Besides efficacy, also selectivity of action on MM cells in comparison to remaining haematopoietic cells was demonstrated for 5 µM ATO but not for 2 µM ATO. DISCUSSION: Our study on primary samples confirmed that ATO has a potential role in therapeutic management of MM. Further controlled studies on MM patients are needed.

Intra- and interlaboratory variability of paroxysmal nocturnal hemoglobinuria testing by flow cytometry following the 2012 Practical Guidelines for high-sensitivity paroxysmal nocturnal hemoglobinuria testing.

BACKGROUND: Sutherland et al. recently published the Practical Guidelines for high-sensitivity detection of paroxysmal nocturnal hemoglobinuria (PNH) clones by flow cytometry (FCM), containing concise protocols for PNH testing. METHODS: Using this approach, we studied the intra- and interlaboratory variability observed in a multicenter study in which fresh blood samples containing three clinically relevant PNH clone sizes within the granulocytic, monocytic, and red blood cell (RBC) populations were shipped to each participating center. RESULTS: Coefficients of variation (CVs) for precision/reproducibility analysis ranged from 0.01%/0.02% to 0.48%/0.45% (big clone), from 0.69%/1.52% to 4.24%/5.80% (small-intermediate clone), from 1.47%/3.91% to 15.01% /17.83% (minor clone) for PNH white blood cells (WBCs) and from 0.24%/0.48% to 1.76%/1.83% (big clone), from 0.80%/1.14% to 2.39%/4.45% (small-intermediate clone), from 1.09%/3.36% to 10.54%/10.23% (minor clone) for PNH RBCs, respectively. Linear regression analysis showed excellent performance correlation between centers (r > 0.99), Wilcoxon rank test revealed no statistically significant differences for PNH granulocytes, monocytes, and RBCs (P > 0.05%), Bland-Altman analysis demonstrated good performance agreement for all target PNH clones (mean bias ranging from -1.47 to 0.71). CONCLUSION: Our results demonstrate very good intra- and interlaboratory performance characteristics for both precision and reproducibility analyses and excellent correlation and agreement between centers for all target PNH clone sizes. Our data confirm the reliability and robustness of the recently published Practical Guidelines approach for high sensitivity PNH testing by flow cytometry and suggest that such an approach represents an excellent basis for standardization of PNH testing by flow cytometry.

Cell markers in the recognition of acute myeloblastic leukaemia subtypes.

The diagnosis of acute myeloblastic leukaemia (AML) is based on cell morphology, cytogenetic and molecular changes, cell markers and clinical data. Our aim was to establish whether morphology and cell markers are comparable in the evaluation of AML. Bone marrow smears were analysed, and flow cytometry and monoclonal antibodies were used to determine cell type and maturity. Morphology and cell markers correlated differently in different AML subtypes.