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5 páginas, 2 figuras., Generation of B and plasma cells involves several organs with a necessary cell trafficking between them. A detailed phenotypic characterization of four circulating B-cell subsets (immature-, naïve-, memory- B-lymphocytes and plasma cells) of 106 healthy adults was realized by multiparametric flow cytometry. We show that CD10, CD27 and CD38 is the minimal combination of subsetting markers allowing unequivocal identification of immature (CD10+CD27−CD38+, 6±6 cells/μL), naïve (CD10−CD27−CD38−, 125±90 cells/μL), memory B lymphocytes (CD10−CD27+CD38−, 58±42 cells/μL), and plasma cells (CD10−CD27++CD38++, 2.1±2.1 cells/μL) within circulating CD19+ cells. From these four subsets, only memory B lymphocytes and plasma cells decreased with age, both in relative and absolute counts. Circulating plasma cells split into CD138− (57±12%) and CD138+ (43±12%) cells, the latter displaying a more mature phenotypic profile: absence of surface immunoglobulin, lower CD45 positivity and higher amounts of cytoplasmic immunoglobulin, CD38 and CD27. Unlike B lymphocytes, both populations of plasma cells are KI-67+ and show weak CXCR4 expression., This work was supported by grants from the Ligue Nationale Contre le Cancer (équipe labellisée 2009), Paris, France, from INCA (n. R07001FN), the Fondo de Investigación Sanitaria, Ministerio de Ciencia e Innovación (FIS 06-0824), Madrid, Spain, Gerencia Regional de Salud de Castilla y León (GRS206/A/08),Valladolid, Spain, the AYUDA PARA LA FINANCIACIÓN DE LOS PROGRAMAS DE ACTIVIDAD INVESTIGADORA DE LOS GRUPOS DE INVESTIGACIÓN DE EXCELENCIA DE CASTILLA Y LEÓN (EDU/894/2009, GR37), Junta de Castilla y León, Valladolid, the Instituto de Salud Carlos III, Ministerio de Ciencia e Innovación (RTICC RD06/0020/0035), Madrid, Spain, and from MSCNET European strep (n. E06005FF) Cancer Centers Research Network.

Udgivelsesdato: 2010-Oct BACKGROUND: Several laboratories have shown that cells with a memory B-cell phenotype can have the same clonotype as multiple myeloma tumor cells. DESIGN AND METHODS: The aim of this study was to determine whether some memory B cells have the same genetic alterations as their corresponding multiple myeloma malignant plasma cells. The methodology included sorting multiple myeloma or memory B cells into RNA stabilizing medium for generation of subset-specific polymerase chain reaction complementary DNA libraries from one or 100 cells. RESULTS: Cells with the phenotype of tumor plasma cells (CD38(++)CD19(-)CD45(-/+)CD56(-/+/++)) or memory B cells (CD38(-)/CD19(+)/CD27(+)) were isolated by flow activated cell sorting. In samples from all four patients with multiple myeloma and from two of the three with monoclonal gammopathy of undetermined significance, we identified memory B cells expressing multiple myeloma-specific oncogenes (FGFR3; IGH-MMSET; CCND1 high) dysregulated by an IGH translocation in the respective tumor plasma cells. By contrast, in seven patients with multiple myeloma, each of whom had tumor plasma cells with a K-RAS61 mutation, a total of 32,400 memory B cells were analyzed using a sensitive allele-specific, competitive blocker polymerase chain reaction assay, but no K-RAS mutations were identified. CONCLUSIONS: The increased expression of a specific "early" oncogene of multiple myeloma (monoclonal gammopathy of undetermined significance) in some memory B cells suggests that dysregulation of the oncogene occurs in a precursor B-cell that can generate memory B cells and transformed plasma cells. However, if memory B cells lack "late" oncogene (K-RAS) mutations but express the "early" oncogene, they cannot be involved in maintaining the multiple myeloma tumor, but presumably represent a clonotypic remnant that is only partially transformed.

Background: Non-Hodgkin's lymphomas are a heterogeneous group of neoplasms arising from the lymphopoietic system including a wide range of subtypes of either B-cell or T-cell lymphomas. The few established risk factors for the development of these neoplasms include viral infections and immunological abnormalities, but their etiology remains largely unknown. Evidence suggests that certain medical conditions may be linked, through immunosuppression, to the risk of non-Hodgkin's lymphoma. Multiple myeloma is a neoplasm of plasma cells that accounts for approximately 15% of lymphopoietic cancers. Increases in the incidence of non-Hodgkin's lymphoma and multiple myeloma in the past implicate environmental factors as potential causal agents. Design and Methods: In the European Prospective Investigation into Cancer and Nutrition (EPIC), 1,213 histologically confirmed incident cases of non-Hodgkin's lymphoma and multiple myeloma (594 men; 619 women) were identified during a follow-up of 8.5 years. Cox proportional hazard models were used to explore the association between self-reported diabetes, diagnosed after 30 years of age, and the risk of non-Hodgkin's lymphoma overall and multiple myeloma and various lymphoma subtypes. Results: We found no association between a personal history of diabetes and the risk of non-Hodgkin's lymphoma overall in men (HR: 1.28, 95% CI: 0.89-1.84), in women (HR: 0.71, 95% CI: 0.41-1.24), or in men and women combined (HR: 1.09, 95% CI: 0.80-1.47). Among the B-non-Hodgkin's lymphoma subtypes, we observed a statistically significant increased risk of B-cell chronic lymphocytic leukemia (HR: 2.0, 95% CI: 1.04-3.86) in men, but not in women (HR: 1.07, 95% CI: 0.33-3.43). Conclusions: This prospective study did not provide evidence for a role of self-reported diabetes in the etiology of non-Hodgkin's lymphoma overall or multiple myeloma. We found an increased risk of B-cell chronic lymphocytic leukemia among men with diabetes, but not among women. We hypothesize that diabetes may not play a causal role in the etiology of B-cell chronic lymphocytic leukemia, though the underlying pathogenic mechanisms of both disorders may include shared genetic, host and/or environmental susceptibility factors. ©2008 Ferrata Storti Foundation.

This is an open access paper.-- et al., The European Myeloma Network (EMN) organized two flow cytometry workshops. The first aimed to identify specific indications for flow cytometry in patients with monoclonal gammopathies, and consensus technical approaches through a questionnaire-based review of current practice in participating laboratories. The second aimed to resolve outstanding technical issues and develop a consensus approach to analysis of plasma cells. The primary clinical applications identified were: differential diagnosis of neoplastic plasma cell disorders from reactive plasmacytosis; identifying risk of progression in patients with MGUS and detecting minimal residual disease. A range of technical recommendations were identified, including: 1) CD38, CD138 and CD45 should all be included in at least one tube for plasma cell identification and enumeration. The primary gate should be based on CD38 vs. CD138 expression; 2) after treatment, clonality assessment is only likely to be informative when combined with immunophenotype to detect abnormal cells. Flow cytometry is suitable for demonstrating a stringent complete remission; 3) for detection of abnormal plasma cells, a minimal panel should include CD19 and CD56. A preferred panel would also include CD20, CD117, CD28 and CD27; 4) discrepancies between the percentage of plasma cells detected by flow cytometry and morphology are primarily related to sample quality and it is, therefore, important to determine that marrow elements are present in follow-up samples, particularly normal plasma cells in MRD negative cases., The meetings were sponsored by the European Myeloma.

Udgivelsesdato: 2008-Mar BACKGROUND: Growth factors are frequently used to aid peripheral blood progenitor cell mobilization from bone marrow. This phase 2 study examined the efficacy and safety of pegfilgrastim for mobilizing peripheral blood progenitors cells for autologous transplantation. DESIGN AND METHODS: Patients with non-Hodgkin's lymphoma received one cycle of mobilizing chemotherapy (ifosfamide, carboplatin and etoposide, ICE). Twenty-four hours later they were randomized, double-blind, to receive a single dose of pegfilgrastim 6 mg or 12 mg, or filgrastim 5 mug/kg/day (until the end of leukapheresis). Following leukapheresis (collection phase), patients rested or received one or two 'salvage' cycles of ICE. High-dose BEAM chemotherapy was then given before peripheral blood progenitor cell transplantation. The primary end-point was the patients' mean yield of CD34(+) cells/kg during the collection phase. RESULTS: Ninety patients were randomized and received a study drug; 63% completed the collection phase. The patients' mean (95% CI) CD34(+) cell harvest per leukapheresis was 0.8 (0.5-1.4), 0.8 (0.5-1.6) and 1.2 (0.7-2.0)x10(6) cells/kg for the pegfilgrastim 6 mg, pegfilgrastim 12 mg and filgrastim groups, respectively. Twenty (69%), 17 (59%) and 23 (72%) patients in these three groups achieved the targeted minimum harvest (>/=2 x 10(6) cells/kg). The mean total harvests were 1.7, 1.4 and 2.2 x 10(6) cells/kg, respectively. Post-transplantation, the median days to absolute neutrophil count recovery (>/=0.5 x 10(9)/L) were 12, 11, and 11, respectively. Pegfilgrastim and filgrastim were generally well tolerated. CONCLUSIONS: Pegfilgrastim (6 or 12 mg) was effective for mobilizing peripheral blood progenitors cells in patients with non-Hodgkin's lymphoma. These data may aid the design of studies to clarify optimal dosing and leukapheresis with pegfilgrastim.

A commercial multiplex reverse transcription polymerase chain reaction screening assay, covering 28 leukemic fusion transcripts, was applied in 143 samples obtained from patients with acute myeloid leukemia at primary diagnosis. In five patients, a cytogenetically unrevealed fusion gene of prognostic importance was detected, while the assay failed to detect one case of t(15;17).