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G E Marti

Publications and source records attributed to G E Marti.

At least 19 recordsLinked to original sources
PubMed2001

Clinical characteristics of familial B-CLL in the National Cancer Institute Familial Registry.

In an ongoing study, families with two or more living cases of B-CLL in first-degree relatives have been recruited through physician and self-referral. Since 1967, 28 kindreds with 73 cases of B-CLL have been enrolled within the National Cancer Institute (NCI) Familial B-CLL Registry. Medical, clinical, and demographic information have been obtained from private physicians, patient interview, hospital records, and death certificates. We used SEER Registry data to compare characteristics of sporadic B-CLL to familial B-CLL. The mean age at diagnosis was approximately 10 years younger among familial cases (57.9 +/- 12.1) than that observed in sporadic cases (70.1 +/- 11.9). A higher percentage of second primary tumors among familial CLL cases compared to reports in sporadic was also observed (16% vs. 8.8%). However, the transformation rate to non-Hodgkin's lymphoma does not appear to be different from that reported for sporadic cases. In conclusion, we observed some differences between familial and sporadic cases; whether any of these characteristics affect survival time or severity of disease is unknown. The study of families with multiple B-CLL cases will aid in delineating the genes and environmental factors that may play a role in the development of both forms of B-CLL.

Age of Onset↗
PubMed2000

Analysis of expressed immunoglobulin heavy chain genes in familial B-CLL.

In this study, we wished to determine whether familial chronic lymphocytic leukemia of B-cell phenotype (CLL) shares with sporadic B-CLL the same immunoglobulin (Ig) heavy chain variable region (VH) gene usage and occurrence of somatic mutation, to gain insight into the pathogenetic relatedness of these epidemiologically distinct forms of CLL. We therefore analyzed the expressed Ig heavy chain genes in 23 cases (11 families) of familial CLL, and compared these results with data previously reported for sporadic CLL. In addition, we assessed the relationship of the occurrence of somatic mutation to several clinical and phenotypic features. The distribution of V genes among these cases was similar to that observed in sporadic CLL: VH3 > VH1 > VH4. Thirteen of the 23 cases (57%) showed germ line VH gene sequences, whereas somatic mutations were detected in 10 cases (43%). The average mutation frequency of these latter 10 cases of was 6.7% (ranging from 1.7% to 8.8%), and evidence of antigen selection was noted in 6. Intraclonal variation, followed by clonal evolution and the appearance of a second clone over a 20-year period was observed in 1 case, suggesting that mutations can continue to accumulate after neoplastic transformation. The presence of somatic mutations correlated with age at presentation, low white blood cell (WBC) count, and low fluorescence intensity of surface CD5, and the potential significance of these relationships is discussed. Our data indicate that familial and sporadic B-CLL display a similar pattern of immunoglobulin gene usage and frequency of somatic mutation, and are consistent with a common ontogeny and immunogenetic origin for these 2 epidemiologically distinct forms of CLL. (Blood. 2000;95:1413-1419)

Adult↗
PubMed2000

Distinct types of diffuse large B-cell lymphoma identified by gene expression profiling.

Diffuse large B-cell lymphoma (DLBCL), the most common subtype of non-Hodgkin's lymphoma, is clinically heterogeneous: 40% of patients respond well to current therapy and have prolonged survival, whereas the remainder succumb to the disease. We proposed that this variability in natural history reflects unrecognized molecular heterogeneity in the tumours. Using DNA microarrays, we have conducted a systematic characterization of gene expression in B-cell malignancies. Here we show that there is diversity in gene expression among the tumours of DLBCL patients, apparently reflecting the variation in tumour proliferation rate, host response and differentiation state of the tumour. We identified two molecularly distinct forms of DLBCL which had gene expression patterns indicative of different stages of B-cell differentiation. One type expressed genes characteristic of germinal centre B cells ('germinal centre B-like DLBCL'); the second type expressed genes normally induced during in vitro activation of peripheral blood B cells ('activated B-like DLBCL'). Patients with germinal centre B-like DLBCL had a significantly better overall survival than those with activated B-like DLBCL. The molecular classification of tumours on the basis of gene expression can thus identify previously undetected and clinically significant subtypes of cancer.

Adult↗
PubMed2000

CD5 is A potential selecting ligand for B-cell surface immunoglobulin: a possible role in maintenance and selective expansion of normal and malignant B cells.

Although the function of CD5 on B cells is unknown, previous studies suggested that CD5 interaction with V(H) framework regions of surface immunoglobulins (Igs) may contribute to survival and expansion of B cells. Here we used B-chronic lymphocytic leukemia (B-CLL) cells and transformed B-cell lines from normal and B-CLL patients to study CD5-Ig interactions. Immobilized Ig binds and permits isolation of CD5 from lysates of CD5-expressing cell lines. Immunoglobulins or Fab fragments of different V(H) families varied in their effectiveness as inhibitors of anti-CD5 staining of CLL cells, appendix and tonsil tissue sections. Human Ig also binds to purified recombinant CD5. We show here for the first time that the unconventional Ig-CD5 interaction maps to the extracellular CD5-D2 domain whereas conventional epitopes recognized by anti-CD5 antibodies are localized in the D1 domain of CD5. We propose that interactions of VH framework regions with CD5 as a ligand may maintain, select or expand normal, autoimmune or transformed B cells and also contribute to skewing of the normal V(H) repertoire.

Antibodies, Monoclonal↗
PubMed1998

Quantitative flow cytometry: inter-laboratory variation.

Quantitative flow cytometry (QFCM) offers a means of standardization within and between flow cytometers. QFCM parameters were set by determining the antibody-binding capacity (ABC) of CD4, CD8, and CD3 cells from 10 normal donors with the use of eight FACScan flow cytometers. QC3 beads and a certified blank bead were used to set up the instruments. Fluorescein isothiocyanate (FITC) conjugated to molecular equivalents of soluble fluorochrome (MESF) microbead standards was used before and after the donor samples were run to ensure that the machines were operating consistently. Lyophilized cells (Cytotrol) were used as a target, to control for antigen expression in the cell preparation. Quantitative Simply Cellular (QSC) beads were used to establish a standard calibration curve for each of the FITC and phycoerythrin antibody conjugates on each of the instruments. Single-parameter fluorescent histograms derived from list-mode files were used to calculate the slope (coefficient of response), intercept (zero channel), number of channels per decade, and ABC or MESF threshold (blank bead). The fluorescence intensity (geometric mean) of the positive and negative donor cell populations was compared with the standard curves, and the ABCs were calculated. The results show consistent instrument performance between laboratories. However, after standardization of CD3, CD4, and CD8 ABCs to microbeads, large variations were noted between donors and laboratories. The source of this variation does not appear to be in the instrumentation but may be due to the lack of an unified set-up protocol, introducing issues of antibody saturation, methods for whole blood lysis and fixation, and the behavior of the microbead standards.

Flow Cytometry↗
PubMed1998

Terminology and nomenclature for standardization in quantitative fluorescence cytometry.

Terminology in any field is a complex mix of established conventions, accepted usages, disputed terms, and occasional misnomers. The terminology that has evolved for quantitative fluorescence cytometry (QFCM) is especially multifarious, in part because QFCM encompasses a range from subjective visual assessments to objective photon counts. Thus, while descriptive terms such as "dim" and "bright" are still quite useful, quantitative terms such as "binding capacity" should be used with collective understanding of their exact meanings. This article reviews current usage and proposes definitions that, with refinement from suppliers and users of QFCM technology, can provide the required clarity.

Calibration↗
PubMed1998

Standardizing flow cytometry: a classification system of fluorescence standards used for flow cytometry.

The growing number of standards commercially available in the field of flow cytometry makes it difficult to know which standards to use to obtain a desired level of quality assurance. A classification system of fluorescence standards has been developed on the basis of their physical characteristics. In turn, these physical characteristics determine the ability of the specific standards to perform selected functions, such as alignment, target referencing, compensation, and calibration. Knowing the properties and limitations of specific standards will help flow cytometer users to select the appropriate standard for the application that they will be performing, especially in regard to intra- and interlaboratory quality assurance. Common protocols used in conjunction with specific classifications of reference standards can provide unified analysis regions or window of analysis across different instruments and/or laboratories. In addition, specific classifications of calibration standards can help select those standards that will provide independent and direct comparison of instrument performance parameters, especially in studies involving multiple laboratories. Knowledge and understanding of the classification system can guide flow cytometer users in more efficient and accurate instrument setup and quality control when conducting research, as well as clinical applications.

Calibration↗
PubMed1998

Flow cytometric enumeration of CD34+ hematopoietic stem and progenitor cells. European Working Group on Clinical Cell Analysis.

The need for a rapid and reliable marker for the engraftment potential of hematopoietic stem and progenitor cell (HPC) transplants has led to the development of flow cytometric assays to quantitate such cells on the basis of their expression of CD34. The variability associated with enumeration of low-frequency cells (i.e., as low as 0.1% or 5 cells/microl) is exceedingly large, but recent developments have improved the accuracy and precision of the assay. Here, we review and compare the major techniques. Based on the current state of the art, we recommend 1) bright fluorochrome conjugates of class II or III monoclonal antibodies (mAbs) that detect all glycoforms of CD34, 2) use of a vital nucleic acid dye to exclude platelets, unlysed red cells, and debris or use of 7-amino actinomycin D to exclude dead cells during data acquisition, 3) counterstaining with CD45 mAb to be included in the definition of HPC, 4) during list mode data analysis, Boolean gating to resolve the CD34+ HPCs from irrelevant cell populations on the basis of the low levels of CD45 expression and low sideward light-scatter signals of HPCs, 5) inclusion of CD34dim and CD34bright populations in the CD34+ cell count, 6) omission of the negative control staining, and 7) for apheresis products, enumeration of at least 100 CD34+ cells to ensure a 10% precision. Unresolved technical questions are 1) the replacement of conventional dual-platform by single-platform assay formats, i.e., derivation of absolute CD34+ cell counts from a single flow cytometric assessment instead of from combined flow cytometer (percent CD34+) and hematology analyzer (absolute leukocyte count) data, 2) the cross-calibration of the available single-platform assays, and 3) the optimal method for sample preparation. An important clinical question to be addressed is the definition of the precise phenotypes and required numbers of HPCs responsible for short- and long-term recovery to optimize HPC transplant strategies.

Antigens, CD34↗
PubMed1997

Comparative analysis of whole blood lysis methods for flow cytometry.

We performed a parallel evaluation of six whole blood lysis methods comparing light scatter and quantitative fluorescence intensity based on quantitative flow cytometry, of selected lymphocyte subsets and CD34+ cells. Leukocytes prepared with FACS Lysing Solution (BDIS), Immunolyse (Coulter) and Optilyse B (Immunotech) consistently gave lower forward scatter values than those prepared with ACK (BioWhitaker), Ortho-mune (Ortho) and ImmunoPrep (Coulter). Debris, defined as CD45 negative events with the threshold off, accounted approximately 80% of all events with ACK and Ortho-mune. The other lysing methods consistently yielded less debris (approximately 50%) with Immunolyse generating only approximately 16% debris. Optilyse and FACS lyse consistently displayed the lowest percentage of lymphoid cells (CD45+/CD14-) in the three part differential. The percentage of CD3+, CD20+, CD5+, and CD16/CD56+ cells was consistent with all methods but CD4 and CD8 determinants showed inconsistent variation with ACK and Ortho-mune. In addition, the fluorescence intensity of CD14 PE and CD8 PE staining was markedly decreased on cells prepared with ImmunoPrep. Finally, the clearest separation of CD34+ cells was observed with ACK and Ortho-mune. Our data demonstrate that the method used for red cell lysis can have definite impact on immunophenotyping and selected methods appear to be more suitable for specific applications.

Antibodies, Monoclonal↗
PubMed1997

Immunization with meningococcal membrane-bound lipooligosaccharide accelerates granulocyte recovery and enhances lymphocyte proliferation in myelosuppressed mice.

Protective effects of detergent-treated outer membrane vesicles (D-OMVs) prepared from the parent group B M986 strain and the nonencapsulated M986-NCV mutant in myelosuppressed mice were investigated in models of experimental septic shock. The effects of D-OMVs on expansion of the myeloid compartment, on spleen cell proliferation to mitogen stimulation, and on cytokines induced during this period were investigated. On 3 consecutive days, mice were injected with 1 microgram/kg of lipooligosaccharide (LOS) or lipopolysaccharide, or 75 micrograms/kg D-OMV followed by a single dose of cyclophosphamide (200 mg/kg) 24 h later. Eight weeks after the last injection, animals were challenged with a combination of galactosamine (400 mg/kg) and live Neisseria meningitidis. More than 90% of control mice died within 24 h when challenged with 10(5) CFU of bacteria. Mice immunized with LOS or D-OMV were rendered neutropenic but were protected against bacterial challenge of at least 10(7) CFU. At different time intervals, peripheral blood samples were obtained to characterize changes in circulating blood cells. The rise in absolute granulocyte numbers occurred 24 h earlier with peak cell counts about 3 times higher than those seen in the placebo groups. Peripheral blood cells from D-OMV-treated animals expressed about twofold more Gr-1 antigen (myeloid surface cell marker) than placebo-treated controls. The proliferative responses to both B and T cells were reduced in all treatment groups due to the effects of cyclophosphamide. D-OMV treatment afforded the greatest protection for mitogen-activated lymphocytes from the lethal effects of cyclophosphamide and also enhanced T and B cell proliferation. Low IL-1 beta levels and increases in serum IL-6 were detected in all treatment groups. In contrast, significant IFN-gamma and IL-3 levels were only detected in D-OMV-treated groups. These results indicate that D-OMVs, which have reduced toxicity, have prophylactic potential in inducing specific cytokines that accelerate granulocyte recovery following cytoreductive therapy by promoting both proliferation and maturation of myeloid precursors as well as augmenting the immune system.

Animals↗
PubMed1996

Requirement for increased IL-10 in the development of B-1 lymphoproliferative disease in a murine model of CLL.

Malignant B-1 cells derived from NZB mice, a murine model of spontaneous autoimmunity and B cell lymphoproliferative disease, produce significantly higher levels of IL-10 mRNA than normal B-1 or B cells. IL-10 may act as an autocrine growth factor for the expansion of malignant B-1 cells. In order to determine if elevated endogenous production of IL-10 was a required element for the malignant transformation of B-1 cells in NZB mice, backcross animals were studied for the linkage between elevated IL-10 expression and the presence of lymphoid malignancy. The phenotypes of aged (NZB x DBA/2)F1 x NZB animals were determined and a strong correlation was found between the elevated levels of IL-10 mRNA and the development of B-1 malignant clones. In contrast, an increased level of IL-10 message was not associated with elevated serum IgM or the presence of anemia or reticulocytosis which is mainly seen in response to autoantibody production. These results indicate that, at least in NZB, the autoimmunity and lymphoproliferation phenotypes are not linked genetically. IL-10 may enhance proliferation and the development of B-1 cell malignancy rather than antibody production by the B-1 cell subpopulation. Thus, IL-10 plays an important role in B-1 malignancies, and downregulation of IL-10 could be a likely site for intervention in B cell malignancies.

Animals↗
PubMed1996

Hematotoxicity among Chinese workers heavily exposed to benzene.

Benzene is a well-established hematotoxin. However, reports of its effects on specific blood cells have been somewhat inconsistent and the relative toxicity of benzene metabolites on peripheral blood cells in humans has not been evaluated. We compared hematologic outcomes in a cross-sectional study of 44 workers heavily exposed to benzene (median: 31 parts permillion [ppm] as an 8-hr time-weighted average [TWA] and 44 age and gender-matched unexposed controls from Shanghai, China. All hematologic parameters (total white blood cells [WBC], absolute lymphocyte count, platelets, red blood cells, and hematocrit) were decreased among exposed workers compared to controls, with the exception of the red blood cell mean corpuscular volume (MCV), which was higher among exposed subjects. In a subgroup of workers who were not exposed to more than 31 ppm benzene on any of 5 sampling days (n = 11, median 8 hr TWA = 7.6 ppm, range = 1-20 ppm), only the absolute lymphocyte count was significantly different between exposed workers (mean [sd]1.6 [0.4] x 10(3) mu L) and controls (1.9 [0.4] x l0(3) uL, p = 0.03). Among exposed subjects, a dose response relationship with various measures of current benzene exposure (i.e., personal air monitoring, benzene metabolites in urine) was present only for the total WBC count, the absolute lymphocyte count, and the MCV. Correlations between benzene metabolites and hematologic parameters were generally similar, although hydroquinone was somewhat more strongly associated with a decrease in the absolute lymphocyte count, and catechol was more strongly associated with an increase in MCV. Morphologic review of peripheral blood slides demonstrated an excess of red blood cell abnormalities (i.e., stomatocytes and target cells) only in the most heavily exposed workers, with no differences in granulocyte, lymphocyte, or platelet morphology noted. Although benzene can affect all the major peripheral blood elements, our results support the use of the absolute lymphocyte count as the most sensitive indicator of benzene-induced hematotoxicity.

Adult↗
PubMed1995

The natural history of a lymphoproliferative disorder in aged NZB mice.

The molecular lesions of human familial and common B-CLL remain unknown. As an approach to this problem, aged NZB mice with a B cell lymphoproliferative disorder were chosen as a murine model. Three groups of NZB mice (2 months, 6 months and > 18 months) for a total of nineteen were studied. A complete autopsy including a CBC was performed on each mouse. Spleen cells were immunophenotyped and cell cycle analysis was performed. Spleen weight, peritoneal cell counts and absolute lymphocytes counts were all elevated in the oldest group. All mice showed evidence of extramedulary hematopoiesis and the older group showed lymphocytic infiltrates in the lacrymal glands, kidneys, liver and lungs. Two of the seven aged mice had a malignant lymphoma. One was a marginal zone lymphoma and the other a lymphocytic lymphoma. Splenic immunophenotyping showed a loss of T cells with an increase in B cells as the mice age. Cell cycle analysis revealed hyperdiploidy in all of the aged mice with a decrease in the percentage G0G1 cells. This disease appears to involve an absolute lymphocytosis of the peritoneum and the peripheral blood compartment. This is associated with splenic aneuploidy. The infiltration of the spleen by malignant cells of varying morphology is a late event. The aged NZB mouse continues to be a model for human B-CLL.

Aging↗