Hematopoietic progenitor cell counting can optimize peripheral blood stem cell apheresis process.

INTRODUCTION: Monitoring of stem cell concentration in transplantation settings is crucial to determine the optimal time of apheresis and is currently based on enumeration of CD34+ cells by flow cytometry. No surrogate marker has replaced CD34+ cell enumeration to date. The aim of this study was the evaluation of the hematopoietic progenitor cell (HPC) parameter of the Sysmex XN-1000 analyzer in terms of optimizing the peripheral blood stem cell apheresis process. MATERIALS AND METHODS: Results of flow cytometric CD34+ cell and Sysmex HPC count were compared in 208 preharvest samples and 139 apheresis products. RESULTS: HPC and CD34+ cell counts showed significant differences in the multiple myeloma (MM) group. The correlation between preharvest HPC and CD34+ cell counts was good in the MM group (rho = .613) and strong in the lymphoma group (rho = .802), allogeneic donors (rho = .923), and other group of samples (rho = .816). The HPC positive cutoff demonstrating 100% specificity and positive predictive value for MM patients was high for ≥20/µL and ≥10/µL CD34+ cell counts, and therefore of limited value. The HPC negative cutoff demonstrating 100% sensitivity and negative predictive value was approximately <4/µL, irrespective of diagnosis. CONCLUSIONS: Based on proposed HPC positive cutoffs (≥31/µL in the lymphoma group and ≥11/µL in the other group of samples), routine HPC enumeration could improve the workflow by replacing CD34+ cell counting in allogeneic donors as well as non-MM patients. Furthermore, based on proposed HPC negative cutoff (<4/µL), CD34+ cell counting could be fully omitted in donors and patients that are not adequately mobilized.

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.

CpG-ODN Stimulation in Population Screening Monoclonal B-Cell Lymphocytosis.

BACKGROUND: Synthetic CpG-oligodeoxynucleotides (CpG-ODN) induce proliferation in normal and malignant lymphocytes B (LyB). This effect is widely exploited in CLL conventional chromosome banding analysis (CBA), which has become reliable only after the cultivation of CLL LyB using CpG-ODN stimulation in combination with IL-2. Monoclonal B-cell lymphocytosis (MBL) differs from CLL mainly in clone size. Only cytogenetic data on recurrent chromosomal aberrations analyzed by fluorescence in situ hybridization (FISH) are available for population screening MBL (sMBL). In sMBL the clone of malignant LyB is typically below 10/µL. We compared CpGODN stimulation in healthy donors and in individuals with sMBL. METHODS: LyB and MBL LyB count were determined by flow cytometry in 15 samples from healthy subjects and 12 MBL cases. Mitotic indices were determined and CBA was done after cultivation of samples by CpG-ODN + IL2. In MBL samples, FISH analysis was performed on isolated LyB. RESULTS: MBL LyB clones in sMBL cases presented less than 1% of WBC and up to 33% of LyB. The MBL group was therefore compared to the group of healthy donors. Although normal and MBL group did not differ in WBC, overall LyB, and normal LyB count, a significantly higher mitotic index was observed in MBL samples (p = 0.0139). We were able to accomplish CBA in all samples which revealed a normal karyotype in all but one case. In this particular sMBL case FISH performed on isolated LyB showed 5% trisomy 12 which was later confirmed by CBA on CpG stimulated blood sample in 15% of metaphases. CONCLUSIONS: Our study, which was done on MBL cases obtained by population screening, confirmed that CpGODN preferentially induced proliferation in MBL LyB over normal LyB. Therefore, CBA can also be successfully accomplished in sMBL and can be used to additionally confirm clonality as well as to improve sensitivity of FISH analysis. Due to coexistence of comparable size of normal and malignant LyB, MBL can serve as a model for exvivo studying of LyB stimulation by CpG-ODN.