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J C Bensa

Publications and source records attributed to J C Bensa.

At least 19 recordsLinked to original sources
PubMed1998

Tumor B cells from non-Hodgkin's lymphoma are resistant to CD95 (Fas/Apo-1)-mediated apoptosis.

Apoptosis mediated by the CD95 (Fas/Apo-1) molecule plays a crucial role in the regulation of the B-cell immune response. In this study, we examined the function of the CD95 antigen in B-cell-derived non-Hodgkin's lymphoma (NHL), a malignant disease of mature B cells. Membrane CD95 molecules were found to be constitutively expressed in a large number of NHL, including mantle cell (MCL, n = 10), lymphocytic (LCL, n = 10), follicular (FL, n = 11), and diffuse large cell lymphoma (DLCL, n = 9) with, however, different levels of intensity. Indeed, the levels of CD95 were low in MCL and LCL as compared with FL and DLCL. However, regardless of the intensity of expression, CD95 triggering with anti-CD95 monoclonal antibody (MoAb) did not induce apoptosis of lymphoma B cells, while these cells underwent apoptosis after irradiation or staurosporine treatment. Further experiments were then performed to address whether apoptosis could be restored by B-cell activation via CD40 cross-linking. We showed that CD40 engagement in the presence of interleukin (IL)-4 was more effective than CD40 engagement alone in upregulating the CD95 antigen and induced CD95-mediated cell death in nontumoral B cells. Concerning malignant B cells, CD40 ligation in the presence of IL-4 strongly increased CD95 expression, but did not markedly increase CD95-induced apoptosis. Furthermore, using cytotoxic T cells, we showed that CD95L was also ineffective in inducing apoptosis in lymphoma B cells, whereas these cells were killed by the perforin pathway. Our findings suggest that the CD95-mediated cell death pathway is altered in malignant cells from the NHL we tested. This could be a mechanism allowing lymphoma B cells to escape from immune regulation.

Antibodies, Monoclonal↗
PubMed1997

Relationships between susceptibility to LAK cell-mediated lysis, conjugate formation and expression of adhesion molecules in B-cell derived non-Hodgkin's lymphomas.

Adoptive immunotherapy with LAK cells has been investigated for the treatment of B-cell-derived lymphomas, but only a few significant tumor regressions were obtained. In order to explain this refractory state, the sensitivity to normal LAK-mediated lysis of 30 non-Hodgkin's lymphoma (NHL) malignant B-cells was determined using flow cytofluorimetry. A large heterogeneity was found, and we report a close correlation (p < 0.001) between the extent of lysis of malignant B-cells and their ability to form conjugates with LAK cells; which is the first step in LAK-mediated cytolysis. The levels of expression of HLA class I molecules, LFA-1 (CD11a/CD18), CD54 and CD58 were also studied and found to be expressed very heterogeneously. CD54 expression on malignant B-cells plays a major role in the initial conjugate formation with LAK cells (p < 0.001), and this was confirmed by inhibition experiments. Our results suggest that a weak expression of CD54 could constitute one mechanism by which NHL tumor B-cells escape natural immune surveillance and resist LAK cells immunotherapies.

Adult↗
PubMed1996

False-negative results in anti-HLA antibody detection by Sangstat ELISA: complement dependent cytotoxicity is not yet obsolete.

Although ELISA on purified HLA molecules for detecting anti-HLA antibody (P-S ELISA) does detect some antibodies previously missed by the conventional complement dependent cytotoxicity method (C Cytotox), HLA ELISA should not fail to detect antibodies already detected by the conventional reference method to be able to make C Cytotox obsolete and to replace it in routine testing. Among 40 selected sera, 8 false-negative reactions were observed in P-S ELISA. These sera were reanalyzed blind in two laboratories and found to contain non-IgM, warm anti- HLA antibodies. These antibodies were directed in 4 cases against an HLA molecule expressed on a kidney transplant previously rejected by the subject. These antibodies, if missed, would have been potentially harmful in kidney transplantation. Thus P-S ELISA can't yet replace C Cytotox in routine anti-HLA class I detection. The cost/benefit ratio of P-S ELISA as a second-line test remains to be investigated.

Antibodies↗
PubMed1996

HCV-Infection in blood donors: association between anti-HCV core IgM antibodies and serum HCV RNA.

Among 47 blood donors tested positive with HCV EIA 2.0 Abbott, 27 (57.4%) also reacted with four ¿third-generation' EIAs. The presence of anti-HCV antibodies was confirmed with 3 different immunoblot assays in 16 of 27 sera (34.0%) while 10 samples (21.3%) had indeterminate profile with antibodies usually directed against structural core antigen. Anti-HCV core IgM response was found in 12 of 47 sera (25.5%) and HCV viremia detected by the polymerase chain reaction (PCR) procedure was observed in 15 samples (31.9%). A comparative study of the different markers confirmed a good correlation between a strong antibody response in EIAs and immunoblot assays and the presence of HCV RNA in the serum; only 2 immunoblot indeterminate samples were PCR positive. An association was observed between IgM antibodies against "core' epitopes and HCV RNA carriage: all IgM-positive sera were found positive by PCR. However, the direct detection of viral genome remains the best method for identifying HCV carriers in the blood donor population.

Adult↗
PubMed1996

Species specificity of anti-beta 2 glycoprotein I autoantibodies and its relevance to anticardiolipin antibody quantitation.

Some patients suspected of having antiphospholipid antibody syndrome (APS) were found to be positive for anti-beta 2 glycoprotein I (beta 2GPI) antibodies despite negative results for antibodies to cardiolipin (ACA). Since the major source of beta 2GPI in the ACA assay is animal (usually bovine) serum, we studied the influence on ACA quantitation of the species specificity of anti-beta 2GPI antibodies from patients with various autoimmune disorders, mostly systemic lupus erythematosus and primary APS. Ninety-seven sera were selected based on IgG (n = 76) or IgM (n = 64) positivity by ELISA using gamma-irradiated plates coated with human or bovine purified beta 2GPI. A higher proportion of IgM (43.7%) than IgG (7.9%) reacted to human, but not bovine, beta 2GPI. Furthermore, from the samples reactive to both proteins, the ratio of antibody level against bovine to that against human beta 2GPI was 1.08 +/- 0.58 for IgG and 0.58 +/- 0.3 for IgM (p < 10(-5)). IgG and IgM ACA were detected in 78 and 40 sera, respectively; concordance between the two ELISAs for ACA and anti-beta 2GPI antibodies was 94% for IgG and 75% for IgM. Out of 28 IgM showing recognition restricted to human beta 2GPI, 21 were missed by the ACA assay, possibly because of lower concentrations of beta 2GPI in those patients' sera. The antibody reactivity pattern towards human and bovine beta 2GPI of individual sera showed no variation with time and was related to the relative antibody avidity for each protein. A murine anti-human beta 2GPI monoclonal antibody, 9G1, that cross-reacts with bovine beta 2GPI, competed to a large extent with the patients' anti-beta 2GPI antibody binding sites whatever isotype involved or protein recognized. Therefore, anti-beta 2GPI antibodies of IgM isotype display a marked preference for human compared to bovine beta 2GPI responsible for frequent inconsistencies in the ACA assay.

Animals↗
PubMed1995

Beneficial effect of one HLA haplo- or semi-identical transfusion versus three untyped blood units on alloimmunization and acute rejection episodes in first renal allograft recipients.

Acute allograft rejection is the major risk factor of renal function decline and graft loss. Beside histocompatibility matches and pharmacological immunosuppression, blood transfusion is empirically used to detect responder subjects and to induce immune tolerance. Alloimmunization associated with blood transfusions readily detected by anti-HLA antibodies could induce acute vascular rejection episodes during the early period after grafting. Our open prospective study was aimed at analyzing the 1 year follow-up of 105 successive first cadaver renal transplant recipients according to the transfusion protocol as assessed by anti-HLA antibody production, acute rejection episodes, and graft survival. Our conventional transfusion protocol involved 3 nonphenotyped blood transfusions set up at least 20 days before grafting in a control cohort (group A) and was compared with a single pretransplant HLA haplo- or semi-identical blood transfusion in a successive group of patients (group B). Our results suggest that both protocols were associated with similar 1-year graft survivals (> 96% in both groups) and number of patients experiencing rejection episodes (20.7% in group A; 9.6% in group B; P NS). HLA haplo- or semi-identical transfusion was significantly beneficial in naive patients without previous alloantigen contact by pregnancy or blood transfusions during dialysis. Naive patients in group B did not develop post-transfusion anti-HLA antibodies compared to naive patients in group A (16.6%; P < 0.001), and they experienced significantly less acute rejection episodes (2.7%) compared to group A naive patients (20.8%; P = 0.02).

Blood Transfusion↗
PubMed1995

Malignant B lymphocytes from non-Hodgkin's lymphoma induce allogeneic proliferative and cytotoxic T cell responses in primary mixed lymphocyte cultures: an important role of co-stimulatory molecules CD80 (B7-1) and CD86 (B7-2) in stimulation by tumor cells.

We analyzed the stimulating capacities of malignant B cells from non-Hodgkin's lymphomas (NHL) to induce an allogeneic response in primary mixed lymphocyte reaction (MLR). T cells purified from a single healthy donor (KS) were used to compare the responses induced by either malignant or hyperplastic cells. Malignant B cells induced strong proliferation of KS cells independently of their level of expression of adhesion molecules. The KS cells after MLR were predominantly CD3+, CD25+, HLA-DR+, Ki67+ and CD45RO+ T cells, and the CD4/CD8 ratio was heterogeneous (from 0.8 to 2.7). To investigate the role of co-stimulatory molecules CD80 and CD86 for the stimulatory capacities of B cells, the expression of both molecules was analyzed before and during the MLR. Most fresh malignant B cells were negative for CD80 and CD86, whereas co-cultured B cells expressed high levels of both molecules. This expression was crucial for T cell proliferation, since monoclonal antibodies directed against CD80 and CD86 completely abrogated the MLR. We also report that KS responding cells at the end of co-culture were able to lyse fresh B cells used as stimulator cells to different extents (from 10 to 51%), and the level of lysis was enhanced after PMA activation of the target cells. Inhibition experiments using CD8 and CD4 mAb showed that effector cells were mainly CD8+. This report is the first to describe the accessory function of human malignant B cells from NHL and their sensitivity to lysis mediated by CD8+ T cells, and suggests new strategies for the development of antitumor immunity in NHL.

Adolescent↗
PubMed1995

Neutrophil activation by anti-beta 2 glycoprotein I monoclonal antibodies via Fc gamma receptor II.

Murine monoclonal antibodies (mAbs) to human beta 2-glycoprotein I (beta 2GPI), a plasma protein required for the binding of some antiphospholipid antibodies, have been shown to possess lupus anticoagulant properties and to activate platelets via Fc gamma receptor (Fc gamma R) crosslinking. Here we investigated their ability to induce polymorphonuclear leukocyte (PMN) functional responses. The six mAbs (IgG1 isotype) tested in combination with beta 2GPI led to a concentration-dependent activation of human PMNs as appreciated by granule release, H2O2 production, and cytosolic Ca2+ increase. This activation process was accompanied by the enhancement of PMN-mediated heparan sulfate loss from the endothelial cell line EA.hy 926 without evidence for cell lysis or detachment. F(ab')2 fragments of one of the mAbs bound to PMNs in a beta 2GPI-dependent manner but were devoid of activating effects. Carbamylated beta 2GPI was unable to mediate PMN-antibody binding and subsequent activation. In addition, cationization of beta 2GPI or removal of its sialic acid groups led to higher efficiency in binding to the PMN surface and triggering activation in comparison with the untreated protein. Thus, the process of PMN activation depends on mAb binding to these cells through both Fab (via beta 2GPI) and Fc domains, as confirmed by the suppression of all responses upon treatment with an anti-Fc gamma RII, but not anti-Fc gamma RIII, antibody. Our data suggest a model of cellular activation by beta 2GPI-dependent antiphospholipid antibodies.

Antibodies, Monoclonal↗
PubMed1995

Autotumour reactive T-cell clones among tumour-infiltrating T lymphocytes in B-cell non-Hodgkin's lymphomas.

Seventy-three T-cell clones (TCC) were established from tumour-infiltrating lymphocytes-T (TIL-T) derived from lymph nodes involved by B-cell non-Hodgkin's lymphomas (B-NHL) in nine patients with different histological subtypes and clinical stages. 40 TCC (55%) expressed the CD25 Ag and were also able to proliferate in the presence of irradiated autologous B-NHL cells. Among them, 23 autotumour (AuTu) proliferative TCC were found not to proliferate to autologous EBV-transformed B-cell lines, indicating that the proliferative reactivity of these TCC was preferentially directed at autologous B-NHL cells. Tested against autologous B-NHL cells, only three AuTu proliferative TCC (CD8+) showed a significant level of cytotoxicity (specific lysis > 15%). In blocking experiments, the AuTu proliferative reactivity of three TCC from one patient was strongly inhibited by anti-DR and anti-DQ mAbs, whereas that of three TCC from another patient was not affected by either anti-MHC class I or class II (DR, DP, DQ) mAbs. These findings suggest that the recognition of autologous B-NHL cells by AuTu proliferative TCC may occur through MHC-restricted as well as MHC-unrestricted mechanisms.

Cell Division↗
PubMed1995

Development of an ELISA for autoantibodies to prothrombin showing their prevalence in patients with lupus anticoagulants.

Some lupus anticoagulants (LA) have been shown to be directed against phospholipid-bound prothrombin. While developing an ELISA to detect anti-prothrombin autoantibodies in patient serum or plasma, no or very low signal was observed using human prothrombin immobilized on plain polystyrene plates. In contrast, the same LA-positive samples bound specifically to prothrombin coated on gamma-irradiated plates, depending on the radiation dose, in the absence of added calcium and phospholipid. Optimization of the assay required the addition of 0.1% Tween 20 to the buffers. Antibody specificity for immobilized prothrombin was ascertained by competition using liposome-bound prothrombin, since fluid-phase prothrombin competed poorly. Seventy-seven of 139 patients (55.4%) with LA related to a variety of underlying diseases possessed anti-prothrombin antibodies (27 IgG, 35 IgM and 15 both isotypes), either isolated or more often associated with anti-beta 2 glycoprotein I (beta 2GPI) antibodies. These included 67-71% of the patients with systemic lupus erythematosus and related disorders, primary antiphospholipid antibody syndrome or drug-induced LA (autoimmune groups), but only 19-20% of those with infection or malignancy (p < 0.001). As previously shown for anti-beta 2GPI antibodies, IgG2 was the predominant IgG subclass reactive with prothrombin. Thus, autoimmune patients with LA have a high incidence of antibodies to beta 2GPI and prothrombin, the binding of which could similarly require high antigen density and/or exposure of cryptic epitopes resulting from protein interaction with an irradiated (i.e. more anionic) polystyrene surface.

Autoantibodies↗
PubMed1994

[Is there a relationship between the presence of autoantibodies or mixed cryoglobulinemia and the clinical and histological characteristics of chronic viral hepatitis C?].

The purpose of this prospective work was to study a possible relationship between autoantibodies, cryoglobulinaemia and liver histologic lesions in chronic hepatitis C. Ninety three patients (mean age: 43.3 years) with histologically proven chronic hepatitis were studied. Chronic hepatitis was associated with cirrhosis in 18 cases. Auto-antibodies detection was performed in the serum of all patients and cryoglobulinaemia detection was performed in 47 patients. The prevalence of auto-antibodies was also studied in 45 blood donors (control group) and 30 patients with chronic hepatitis B. Histologic study included Knodell score and semi-quantitatively expressed histologic lesions considered as more specific of chronic hepatitis C. Twenty six of the 93 patients (28%) had at least an autoantibody with a level > or = 1/100. The autoantibodies prevalence was: smooth muscle: 15%, antinuclear: 15%, LKM 1: 1.2%, mitochondrial: 0. A mixed cryoglobulinaemia was present in 23 of 47 patients (49%). The prevalence of anti-smooth-muscle autoantibodies was significantly increased in hepatitis C patients compared with the control group (P < 0.05). The histologic Knodell score was 7.3 +/- 3.6. The histologic lesion prevalence was: portal tract lymphoid follicles: 97%, acidophil bodies: 85%, intra-sinusoidal lymphoid infiltrates: 71%, steatosis: 61%, microgranulomas: 54%, biliary duct tract damages: 53%. No statistical significant correlation was found between autoantibodies prevalence and liver histologic lesions. The Knodell score was only significantly increased in patients with mixed cryoglobulinaemia (8.4 +/- 3.6 vs 6.2 +/- 2.8) (P < 0.05). These results suggest that the autoantibodies presence in chronic hepatitis C does not change hepatic histologic lesions.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1993

Evaluation of monoclonal antibodies with specificity for the human platelet HPA-1 allotypes.

Two mouse monoclonal antibodies have been characterized. Both antibodies specifically recognized the amino acid sequences which are responsible for the presence of the HPA-1a and HPA-1b alloantigens at the surface of human platelet. The monoclonality allied with an exquisite specificity of these antibodies allow a perfect typing of platelet HPA-1 status. A fast and reliable Elisa assay which fulfills all the needs and requirements of hematology laboratories has been set up and is described here. The Elisa assay has been tested on a population of 689 blood donors. The results agreed with the known phenotypic frequencies of the HPA-1 alloantigens.

Amino Acid Sequence↗
PubMed1992

CD45RA expression by CD4 T lymphocytes in tumors invaded by B-cell non-Hodgkin's lymphoma (NHL) or Hodgkin's disease (HD).

Little is known about the role of tumor infiltrating T lymphocytes (TIL-T) in the pathogenesis of malignant diseases and collaboration between normal and malignant cells has not yet been proved. In the present work, we have investigated whether immune T lymphocytes exist in tumors invaded by B-cell non-Hodgkin's lymphoma (NHL) or Hodgkin's disease (HD). Therefore, we have studied the reactivity of the CD45RA monoclonal antibody, which discriminates between naive and memory CD4 T lymphocytes. Our results showed far lower percentages of CD4+ CD45RA+ in malignant lymphoma (30.3 +/- 15.0% in B-cell NHL, and 37.4 +/- 18.6% in HD) than in reactive hyperplasia (54.7 +/- 13.2%), leading to the conclusion of an accumulation of immune cells in tumor microenvironment. A further heterogeneity in the relative proportion of naive and memory TIL-T was also observed within lymphoma (range: 11 to 68% in B-cell NHL, 5 to 69% in HD). In B-cell NHL, it was related to histological features, as documented by the Kiel classification (P = .028), and to a stronger extent to cytological characteristics analysed with the Grenoble classification (P less than .0001): class 1 NHL, which are essentially indolent NHL displayed lower naive cells (22.2 +/- 7.4%) than class 3 NHL, which are more aggressive (40.1 +/- 16.1%). Among the monoclonal antibodies (mAb) defining the B-cell clone phenotype or activation state (CD19, CD20, CD21, CD22, CD23, CD24, CD5, CD10, CD11a, and Ki67), only CD23 (P = .0003) and Ki67 (P = .0007) revealed statistical association with the percentage of naive CD4 lymphocytes. No correlation could be demonstrated with the proportion of whole TIL-T, activated CD3 DR TIL-T, or CD4 subset.

Adult↗
PubMed1991

Membrane cell permeabilization with saponin and multiparametric analysis by flow cytometry.

Saponin, a detergent like molecule, can permeabilize cell membranes without destroying them, and thus can be used for the detection of intracellular antigens on intact cells with a flow cytometer. First experiments were reported that demonstrated the detection of intracytoplasmic antigens such as intermediate filaments and CD3 in T acute lymphoblastic leukemia (ALL). Further experiments were also performed to prove that intranuclear structures were equally accessible: dyes such as propidium iodide (PI) and monoclonal antibodies (mAb) such as Ki67 could penetrate the nucleus and lead to the analysis of DNA content and to the discrimination between the different cell cycle phases (G0, G1, S, G2-M). This rapid and sensitive method retained sufficient integrity of cells being treated to enable differentiation of cell types on the basis of morphology. Furthermore, it did not alter membrane expression of most antigens. Therefore, it was of particular interest for multiparametric analysis, especially for simultaneous study of membrane and intracellular structures.

Aneuploidy↗
PubMed1990

T lymphocytes from invaded lymph nodes in patients with B-cell-derived non-Hodgkin's lymphoma: reactivity toward the malignant clone.

Tumor-infiltrating T lymphocytes (TIL-T) are always present in B-cell-derived non-Hodgkin's lymphoma (NHL). In this investigation, we explored the possibility that collaboration might exist between these cells. TIL-T were isolated from 39 lymph nodes of patients with NHL. In most of the cases, few of them (less than 10%) possessed surface activation receptors CD25 or OKT9. In 80% of the cases, they proliferated in response to recombinant interleukin-2 (rIL-2), but the degree of proliferation was often low as compared with control populations. The influence of irradiated autologous malignant cells on the TIL-T proliferation in response to rIL-2 (40 U/mL) was also investigated: in 38% of the cases, this proliferation was not modified (group O), and in 41% it was higher (group +) and in 21% it was lower (group -). The mechanism of this immune response (specific or not) is not elucidated at present. The definition of these groups was statistically correlated with different parameters of the disease: (1) percentage of TIL-T was higher in group + (44% +/- 17%) than in group O (31% +/- 18%) and group - (24% +/- 15%); (2) B-cell proliferation in centrofollicular lymphomas was more frequently nodular or nodular and diffuse in group + (83%) and O (55%) than in group - (0%); (3) low-grade malignancies in the Working Formulation were more frequent in group + (75%) than in group O (60%) or group - (12%); (4) favorable prognosis evaluated with the Grenoble cytologic classification was more frequent in group + and O (87%) than in group - (12%); (5) actuarial survival curves showed a significantly better prognosis for patients in group +.

Adult↗