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T Lavabre-Bertrand

Publications and source records attributed to T Lavabre-Bertrand.

At least 37 records · Page 2Linked to original sources
PubMed1996

Quantification of CD1a, HLA-DR, and HLA class I expression on viable human Langerhans cells and keratinocytes.

In order to determine precisely the cellular density of surface molecules that are critical for antigen presentation in human epidermis, we utilized a quantitative immunofluorescence indirect assay and performed flow cytometric analysis of human epidermal cell (EC) suspensions. We first demonstrated that Tricolor-labeled streptavidin coupled to Cy-5 (SA-TC) was a reliable marker for non viable EC and that SA-TC+ EC accounted for the frequent nonspecific background of fluorescence due to isotype controls binding, although Langerhans cells (LC) and Keratinocytes (Kc) express Fc receptors for IgG on their surfaces. These results indicate that quantification of cell surface antigens on human EC requires the concomitant use of a marker of viability. Multicolor flow cytometric analysis allowed us to quantify CD1 molecules and major histocompatibility complex (MHC) antigens on viable human LC and Kc. Our results demonstrated a weak expression of MHC class I molecules on viable LC (163 +/- 19 x 10(3) molecules/cell) compared to viable Kc (785 +/- 110 x 10(3) molecules/cell). Mean antigen density of HLA-DR and CD1a molecules on viable LC were 579 +/- 82 x 10(3) molecules/cell and 1600 +/- 133 x 10(3) molecules/cell, respectively. Quantitative flow cytometry of viable EC may be proposed to evaluate the number of membrane antigens whose level of expression is related to cellular maturation or activation that occurs in skin diseases.

Adult↗
PubMed1996

Flow-cytometric quantitation in chronic leukemias.

Flow cytometric quantitation in chronic leukemias provide relevant information in different areas. It allows the characterization of additional leukemia associated parameters, like over- or under- expression as compared to normal counterparts, that is suitable for the diagnosis of malignancy or for residual disease evaluation. It improves scoring systems for the differential diagnosis between the different chronic malignancies. It allows to find original pronostic parameters and improves the comparison of different series due to a better definition of positivity. It helps to the monitoring of immune based therapeutic regimens. It provides new relevant pathophysiological informations, for instance in the study of apoptosis, as a tool for quantitative evaluation of the apoptotic process itself and for the study of its mechanism. Since its first description by Minot and Isaacs in 1924, chronic lymphocytic leukemia (CLL) has been extensively studied, due in part as it has been demonstrated as the more frequent leukemia in the Western world (Gale and Foon 1987). In addition, clinical features, cell morphology, immunological markers, histopathology and molecular genetics have been used progressively to define and characterize a wide spectrum of chronic lymphoproliferative disorders which had been previously gathered in the same entity than CLL (Benett et al., 1989, Catovsky and Matutes 1991, Harris et al., 194). Immunologic techniques are now routinely used for diagnosis in this context. Since there is no marker specific for each of these entities, scoring systems have been proposed to help diagnosis (Matutes and Catovsky 1994), which are currently investigated in multicentric studies. Flow cytometry is now widely used for immunophenotyping purposes. It allows, in addition to the determination of the percentage of positive cells, to determine the intensity of fluorescent staining, that can be converted into antigen density provided that reagents are used under saturating concentrations and correct standards of fluorescence are tested in parallel. The concept of antigen density evaluation appears to improve the efficiency of immune techniques in the monitoring of hemopoietic malignancies (Lavabre-Bertrand et al., 1994c). The present review will focus on the specific interest of immune quantitation in the study of chronic lymphoid malignancies, with a successive emphasis on diagnosis of malignancy, distinction between the different chronic lymphopathies, prognostic and therapeutic relevance, then on pathophysiological interest.

Chronic Disease↗
PubMed1996

Nephrotic syndrome associated with chronic lymphocytic leukemia resistant to immunosuppressive drugs: remission obtained by splenectomy.

Chronic lymphocytic leukemia is a common disease in the elderly but is rarely associated with a nephrotic syndrome. The rarity of this association suggests that leukemic cells may have certain properties or features that may lead to the development of glomerulonephritis. Effective medical treatment of the leukemia may not necessarily allow regression of the nephrotic syndrome; however, the effects of splenectomy on nephrotic proteinuria when associated to chronic lymphocytic leukemia have never been evaluated. We report the case of a 50-year-old male with stage C CD5+ chronic lymphocytic leukemia associated with a nephrotic syndrome due to Type I membranoproliferative glomerulonephritis. Chlorambucil and prednisone were unable to control the leukemia and the nephrotic range proteinuria, and were discontinued because of poor hematologic tolerance. A splenectomy immediately resulted in a spectacular remission of both chronic lymphocytic leukemia and the nephrotic syndrome. Spleen lymphocytes were collected and tested in quantitative flow cytometry for the expression of the main B cell associated markers. They did not exhibit any particular immunophenotypic pattern. This report of a remission of a glomerulonephritis associated with chronic leukemia following splenectomy is evidence of a possible relationship between the two diseases.

Glomerulonephritis, Membranoproliferative↗
PubMed1995

Biologic effects of anti-interleukin-6 murine monoclonal antibody in advanced multiple myeloma.

In patients with advanced multiple myeloma (MM) there is an excess of production of interleukin-6 (IL-6) in vivo, and elevated serum levels are associated with plasmablastic proliferative activity and short survival. These data prompted us to perform a clinical trial with a murine anti-IL-6 monoclonal antibody (MoAb) to neutralize the excess of this putatively deleterious factor in these patients. Ten MM patients with extramedullary involvement frequently were treated with anti-IL-6 MoAb. The MoAb was administered intravenously to 9 patients; 1 patient with malignant pleural effusion received intrapleural therapy. Of the 3 patients who succumbed to progressive MM after less than 1 week of treatment (including the only 1 treated locally), 2 with evaluable data exhibited marked inhibition of plasmablastic proliferation. Among the 7 patients remaining more homogeneous receiving the anti-IL-6 MoAb for more than 1 week, 3 had objective antiproliferative effect marked by a significant reduction of the myeloma cell labelling index within the bone marrow. One of these 3 patients achieved a 30% regression of tumor mass. However, none of the patients studied achieved remission or improved outcome as judged by standard clinical criteria. Of major interest, objective antiproliferative effects were associated with complete inhibition of C-reactive protein (CRP) synthesis and low daily IL-6 production in vivo. On the other hand, the lack of effect in 4 patients was associated with a higher IL-6 production and inability of the MoAb to neutralize it. Anti-IL-6 was also associated with resolution of low-grade fever in all the patients and with worsening thrombocytopenia and mild neutropenia. The generation of human antibodies to Fc fragment of the murine anti-IL-6 MoAb observed in 1 patient was associated with dramatic progression. These data show that anti-IL-6 MoAb can suppress the proliferation of myeloma cells and underscore the biologic role of IL-6 for myeloma growth in vivo. Furthermore, suppression of CRP and worsening of neutropenia/thrombocytopenia both indicate that IL-6 is critically involved in acute-phase responses and granulopoiesis/thrombopoiesis.

Acute-Phase Reaction↗
PubMed1995

Detection of membrane and soluble interleukin-6 receptor in lymphoid malignancies.

We studied the membrane expression of the gp80 chain of IL-6 receptor (IL-6R) by quantitative flow cytometry in chronic lymphocytic leukaemia (CLL) and leukaemic centrocytic lymphoma using a panel of seven monoclonal antibodies. IL-6R was detected in 18/26 CLL cases and 4/7 lymphoma cases, with a mean antigen density < 3000 molecules/cell. Multiple labelling experiments confirmed the IL-6R expression by neoplastic cells. Specific mRNA was found by RT-PCR in neoplastic cells. A specific ELISA test was designed using two anti-IL-6 receptor MAbs to measure the serum soluble IL-6R (sIL-6R) in CLL (n = 48). B-cell non-Hodgkin's lymphoma (NHL; n = 40), and monoclonal gammopathy (MG; n = 32). SIL-6R was higher in CLL (170 +/- 12.6 ng/ml) in NHL (160 +/- 12 ng/ml) and MG patients (183 +/- 23 ng/ml) than in age-matched controls (100 +/- 5.6 ng/ml; P < 0.001) and higher in high-grade than low-grade NHL. No correlation was noted with a previous treatment. Among CLL cases the patients classified as stage B according to the Binet's staging of the disease had the highest sIL-6R values, thus suggesting a link with tumour cell mass.

Antibodies, Monoclonal↗
PubMed1995

alpha-Interferon therapy for congenital dyserythropoiesis type I.

We report the case of a 28-year-old female followed for congenital dyserythropoiesis type I which required repeated transfusions. Alpha-2a interferon treatment was started because of post-transfusion chronic viral hepatitis type C. Following this treatment, haemoglobin level increased and reached normal value during the 24 weeks of interferon treatment. When interferon therapy was stopped, haemoglobin level returned to previous values, requiring more transfusions. Resumption of interferon therapy resulted again in a complete normalization of haemoglobin level. Erythrokinetic studies demonstrated a striking reduction of the ineffective erythropoiesis, and electron microscopy study a reduction in nuclear structure abnormalities. To our knowledge, this is the first report of the efficacy of interferon in congenital dyserythropoiesis.

Adult↗
PubMed1994

Leukemia-associated changes identified by quantitative flow cytometry: I. CD10 expression.

We have compared CD10 antigen expression in normal fetal bone marrow with that of B-linage acute lymphoblastic leukemia (ALL). Both quantitative indirect immunofluoresence (QIFI) and direct immunofluorescence (IF) tests with Quantum beads were used to convert median fluorescence intensity (MFI) values into numbers of antigen molecules expressed per cell (AgE). Lymphoid precursors in the fetal marrow and liver expressed 3-12.5 x 10(3) CD10 molecules/cell with an upper limit of 5 x 10(4)/cell (MaxAgE). The median CD10 AgE in the different cases of acute B-lineage ALL were variable and ranged from undetectable to very high values (> 1.8 x 10(5). In 24 of the 72 cases (33%) tested with QIFI the median CD10 AgE was above the highest values seen in normal samples (> 5 x 10(4)/cell). An additional 23.6% of cases had higher median values than the normal median CD10 AgE. Next, CD10 antigen was quantitated in 78 cases during the routine multiparameter analysis of B-lineage leukemia using CD10/class II/CD34 3-color IF test or CD10/TdT 2-color IF test. The aberrant overexpression was confirmed in 43.6% of ALL cases. The CD10bright display suggested ALL diagnosis even when few cells were available for study, e.g., in early relapse and in ALL masquerading as aplastic anemia. The levels of CD10 expression were maintained in relapse. In addition, different CD10 levels were associated with the various chromosomal alterations: high CD10 levels (> 3 x 10(4)/cell) with hyperdiploidy, low CD10 levels (1.8-4 x 10(3)/cell) with the t(1;19) and undetectable levels (< 1.2 x 10(3)/cell) with the t(4;11) translocations.(ABSTRACT TRUNCATED AT 250 WORDS)

Biomarkers, Tumor↗
PubMed1994

CD23 antigen density is related to serum gamma globulin level, bone marrow reticulin pattern, and treatment in B chronic lymphocytic leukemia.

The CD23 antigen density was evaluated by a cytofluorometric technique in 55 patients with chronic lymphocytic leukemia. The quantification method was based on the use of biological standards in indirect immunofluorescence. The CD23 antigen density was correlated with the percentage of CD23 positive cells, but antigen density appeared to be a more informative parameter. CD23 antigen density was lower in stage B than in stages A or C patients, and higher in patients undergoing chemotherapy or previously treated than in untreated patients. There was a significant negative correlation between CD23 antigen density and serum gamma globulin and IgG levels, that existed only in patients in an advanced stage of the disease. CD23 antigen density was higher in patients with abnormal bone marrow reticulin pattern. Serum gamma globulin level was lower in these patients, as well as in patients with prognostically unfavorable histologic bone marrow infiltration pattern. These data emphasize the interest of antigen density as an additional parameter and the complex relationship between CD23 expression, hypogammaglobulinemia, bone marrow histologic findings, and treatment in chronic lymphocytic leukemia.

Antibodies, Monoclonal↗
PubMed1994

Leukemia-associated changes identified by quantitative flow cytometry. II. CD5 over-expression and monitoring in B-CLL.

The CD5 antigen density on B cells was studied on fetal spleen, cord blood, and adult peripheral blood (after immunomagnetic bead purification) using an indirect immunofluorescence technique. In fetal spleen, there was a continuum in CD5 expression, whereas all cord blood and less than 20% adult peripheral blood B cells were CD5+. Mean CD5 antigen density on these normal cells was low (3-6 x 10(3) molecules/cell); eight to 20 times lower than on normal T lymphocytes. In adult blood, less than 10% B cells expressed more than 3 x 10(3) CD5 molecules/cell. In chronic malignancies, 34/35 cases had a CD5 antigen density lower than on residual T cells, but mean antigen density was higher (14.8 +/- 2.1 x 10(3) molecules/cell) than on normal B cells. Sixteen cases of chronic lymphocytic leukemia (50%) expressed a CD5 density above 10 x 10(3) molecules/cell. This aberrantly high CD5 expression was used to detect neoplastic cells after dilution in normal lymphocytes, with a limit of detection between 1:100 and 1:1000. Quantitation of the CD5 antigen allows better characterization of the B1 population and should be used for the monitoring of chronic malignancies.

Antigens, CD↗
PubMed1994

Quantitative immune phenotyping: a new dimension for the monitoring of haemopoietic malignancies.

Quantitative data provided by flow cytometers are as yet not fully exploited due to the lack of standardization. However, fluorescence standardization systems are now available which allow the measurement of antigen density on a routine basis and the present review focuses on the interest of such quantitative techniques for the monitoring of haemopoietic malignancies. Antigen quantitation: (i) permits a more objective characterization of positivity, especially in the case of weakly expressed antigens; (ii) facilitates the analysis of complex populations, since certain antigens are expressed at different levels on different cell subsets; (iii) provides new data contributing to a more precise definition of cell differentiation; (iv) is of value to ascertain malignancy from the detection of aberrant antigen densities on putative neoplastic cells; (v) provides additional parameters suitable for the evaluation of residual disease and for the monitoring of immunological therapeutic regimens; (vi) contributes to prognosis. Quantitation of antigen densities should therefore be included in the routine study of haemopoietic malignancies.

Antigens, Neoplasm↗
PubMed1994

Quantification of CD24 and CD45 antigens in parallel allows a precise determination of B-cell maturation stages: relevance for the study of B-cell neoplasias.

Quantitative expression, i.e. absolute number of monoclonal antibody molecules bound per cell, was evaluated for CD24 and CD45 by flow cytometry with standards of fluorescence intensity on a panel of normal and neoplastic B cells. The CD24 antigen was expressed at homogeneous high level in fetal bone marrow and liver. Its density decreased progressively in the other normal tissues in parallel with the B-cell maturation. The ratio between CD24 density measured on fetal bone marrow B cells and that seen on adult peripheral B cells was 6:1. The CD45 antigen density was lower on fetal bone marrow cells than in the more mature stages. Fetal spleen lymphocytes and all the mature B lymphocytes displayed the same CD45 density than that seen on normal adult peripheral T cells. The CD24/CD45 antigen density ratio was precisely related to the stage of B-cell maturation. The same pattern of variation of CD24 and CD45 antigen density was seen on B-cell neoplasias, with a significantly higher value of CD24 and lower value of CD45 in acute lymphoblastic leukemias than in chronic malignancies. CD24 and CD45 antigen levels were frequently out of the range observed in the corresponding normal population. Among ALL patients, a low CD24/CD45 antigen density ratio was associated with a good prognosis. These data confirm the interest of an absolute quantitative study for widely distributed antigens.

Antigens, CD↗
PubMed1993

B-cell chronic lymphocytic leukaemia populations respond stochastically to combinations of growth signals in vitro.

The ability of B-CLL lymphocyte populations to respond to cytokine stimulation of mononuclear cultures was examined using 3-colour immunofluorescence and multiparameter flow cytometry. The simultaneous detection of the membrane antigens CD5 and CD19, with the proliferation antigen Ki-67, allowed examination of the cell-cycle entry of the B-CLL lymphocyte population. Upon stimulation with IFN-gamma, IFN-gamma+IL-2, TPA+IL-4, between 10 and 44% of B-CLL lymphocytes from 10 patients were stimulated to enter into cell-cycle. This B-CLL response was notably more homogenous than the non-clonal lymphocyte response. Except in the case of IFN-gamma alone, T-cell response did not correlate with B-CLL response, suggesting B-CLL lymphocytes respond directly to combinations of growth signals. Considering the B-CLL population as homogenous, B-CLL lymphocytes respond in a stochastic manner.

Aged↗
PubMed1992

A study of 15 cases of primary mediastinal lymphoma of B-cell type.

Fifteen cases of pure supradiapragmatic lymphoma with initial prominent antero-superior mediastinal involvement displaying a B-cell pattern of reactivity were studied. These cases occurred in six men and nine women with a median age of 33 years at diagnosis (range, 23 to 75 years). Supradiapragmatic peripheral lymphadenopathies were present in three cases, and intrathoracic extension to the lung, pericardium, or pleura was possible. In five cases a thymic origin was obvious. All cases exhibited a B-cell pattern of differentiation, with a great variety of histopathologic aspects associated with a high frequency of fibrosis and/or necrosis. Hodgkin's disease was initially misdiagnosed in four cases. The evolution was purely local, with extrathoracic extension in five cases, at the ultimate phase of the disease. The prognosis appeared to be poor with only five patients still alive at a median survival time of 16 months. A complete chemoresistance and radio-resistance was observed in seven cases; only two complete remissions were achieved with aggressive chemotherapy. Prolonged remission could be achieved after surgical reduction of the mass. Primary B-cell mediastinal lymphoma appears to be a distinct clinical entity with local evolution and resistance to therapy. A new therapeutic regimen, which could include surgery in some cases, should be found for this disease.

Adult↗
PubMed1992

[Cancer of the testis after Hodgkin's disease. Apropos of 2 cases].

We report about two cases of cancer of the testis occurring 2 and 7 years after Hodgkin's disease treated with combined chemotherapy and radiation therapy. From an etiopathogenic point of view, this association may, of course, be accidental, but it may also have an iatrogenic origin or be caused by contiguous carcinogenesis, or even by an immune deficiency. In addition to orchidectomy, the therapeutic history of these patients requires an adaptation of the treatment of their tumors of the testes.

Adult↗