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Biomedical subjects

J C Bensa

Publications and source records attributed to J C Bensa.

At least 37 records · Page 2Linked to original sources
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↗
PubMed1992

DNA typing: an important step forward? Collaborative Transplant Study.

In a collaborative project which was supported by 96 transplant centers, DNA typing of HLA-DR antigens was carried out on over 7,000 transplant donors and recipients at 8 participating laboratories. Approximately 25% of the individuals were found to have been typed incorrectly by serological means. An analysis of over 2,500 first cadaver kidney transplants showed a significant correlation of matching for the HLA-DR antigens in transplants where the serological typing was confirmed by DNA typing. In transplants where the serological typing was found to be incorrect, the analysis of serological HLA-DR mismatches resulted in no correlation with graft outcome whereas a significant correlation was found when the corrected DNA typed HLA-DR antigens were analyzed. Transplants which had been reported to the Collaborative Transplant Study based on serological typing as matched for HLA-A, -B, -DR or HLA-B, -DR were found to have a superior graft survival rate only if HLA-DR compatibility was confirmed by DNA typing.

DNA Fingerprinting↗
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↗
PubMed1990

Translocation t(3;22)(q23;q11) in three patients with diffuse large B cell lymphoma.

In our series of 134 patients with a diagnosis of non-Hodgkin's lymphoma (NHL) and clonal chromosomal abnormalities, three were found to show an identical t(3;22)(q28;q11) translocation. All were old patients with isolated lymphadenomegaly and diffuse large noncleaved cell lymphoma. All expressed a B cell immunophenotype, and all entered a complete remission when treated with aggressive chemotherapy. This translocation could, therefore, delineate a particular subtype of diffuse large cell NHL.

Aged↗
PubMed1989

[Lymphocyte subpopulations during a longitudinal survey in an endemic malaria zone].

In a longitudinal survey conducted in savanna area (Burkina Faso, West Africa) where malarial transmission is seasonal, we studied modifications of T, B lymphocytes, NK cells, and CD4+, CD8+ and activated T subpopulations of 61 patients (31 adults and 30 children, among them 20 showed at least one malarial attack during the survey). Analysis was made by direct immunofluorescence on a cytofluorimeter. Our study did not show any significant differences in lymphocytes subpopulations according to age or presence of malarial attack. None of the lymphocyte markers in the peripheral blood are related to premunition, may be because host/parasite conflict mainly occurs in deep organs.

Adolescent↗
PubMed1986

[Malignant non-Hodgkin's lymphoma associated with a serum monoclonal immunoglobulin].

Among the 394 non-Hodgkin's lymphomas (NHL) observed at our hospital over a thirteen year period, we have found 17 associated monoclonal gammopathies (4.3%). Fourteen gammopathies could be correlated to the lymphoid tumor due to a study of immunological membrane markers and to the comparative evolution of the disease and the monoclonal gammopathy. Two different groups could be distinguished: Six patients out of the fourteen studied (43%) had a gammopathy similar to the surface immunoglobulins of the tumour lymphoid cells. Seven of the seventeen showed, after treatment, a parallel evolution between the tumor and the gammopathy. This originates directly from the tumoral secretion and deserves to be classified among the B lymphoid excretory tumors. Six were IgM and one was IgG. Eight of the fourteen patients studied (57%) did not show any immunological relation between the lymphoma and the monoclonal gammopathy. The evolutions (10 of the 17 patients) of the tumor and of the gammopathy were independent. Among the eleven gammopathies (1 double gammopathy), 5 were IgG, 4 were IgA and 2 were IgM. The incidence of these gammopathies related to the total group tf lymphomas is 2.5%. Given the age of these patients, the association seems fortuitous.

Adult↗
PubMed1986

Characteristics of complement subcomponents C1r and C1s synthesized by Hep G2 cells.

The association and activation states of complement subcomponents C1r and C1s biosynthesized by Hep G2 cells were studied. C1r and C1s are secreted in stoichiometric amounts; in the presence of Ca2+ they are associated in a complex that sediments similarly to plasma C1r2-C1s2. Both compounds are synthesized as monomer proteins of apparent Mr 86 000. C1r is secreted as a dimer. Secreted C1r is not autoactivatable but undergoes proteolysis by exogenous C1r; secreted C1s is also proteolysed by exogenous C1r. In the presence of immune-complex-bound C1q, secreted C1r and C1s are able to reconstitute C1, but normal activation requires extrinsic C1r2-C1s2.

Animals↗
PubMed1985

Characterization of C1q, C1s and C-1 Inh synthesized by stimulated human monocytes in vitro.

C1q, C1s and C1 Inh synthesized and secreted by human monocytes were characterized by SDS-PAGE. C1q is formed of three chains A (Mr approximately 35 000), B (Mr approximately 33 000) and C (Mr approximately 25 000) which are associated in two subunits A-B and C-C. It appears identical to C1q purified from plasma. C1s is secreted as a non-activated, monocatenar protein of Mr approximately 87 000 identical to proenzymic C1s from plasma. Secreted C1 Inh (Mr approximately 100 000) has a slightly higher Mr than purified plasmatic C1 Inh. Monensin treatment of the cells favours the intracytoplasmic accumulation of products at various glycosylation stages.

Cells, Cultured↗
PubMed1985

In vitro study of Fc-receptor function in autoimmune diseases.

A simple test for studying in vitro Fc-receptor function of mononuclear phagocytes is described. Immune phagocytosis is analyzed as a dynamic phenomenon by using nearly pure suspensions of monocytes incubated for diverse times with autologous erythrocytes sensitized with highly purified IgG. In a series of normal volunteers and patients with vasculitis a strict correlation has been found between this in vitro assay and the measure of splenic clearance of IgG-coated red blood cells (RBC), the classical approach for studying in vivo macrophage Fc-receptor function by using sodium chromate 51Cr as tag. The use of this in vitro assay appears to be valuable mainly in cases requiring repeated measurements of Fc-receptor function for monitoring the course of disease or the effects of therapy.

Autoimmune Diseases↗
PubMed1984

Characterization of the C1q receptor on a human macrophage cell line, U937.

The binding of C1q to the human macrophage cell line U937 has been studied. Fluorescence microscopy with fluorescein-conjugated F(ab')2 anti-C1q antibody showed that 100% of the cell population is able to bind exogenous C1q. Monomeric C1q binding to U937 cells is very weak at normal ionic strength (I0.15) and was therefore investigated at I0.07, conditions which stabilize the binding. However, aggregation of C1q on dextran sulphate or a lipid A-rich lipopolysaccharide allowed a firm, binding at I0.15. Quantitative binding studies with monomeric 125I-C1q showed a concentration-dependent, saturable, specific and reversible binding involving specific membrane receptors. Scatchard plots of C1q binding indicated [1.6 +/- 0.7 (1 S.D.)] X 10(6) sites per cell with an equilibrium constant of (2.9 +/- 1.8) X 10(7) M-1 at I0.07. The location of the molecule region mediating C1q binding was established with collagen-like fragments prepared by partial pepsin digestion, confirming earlier results obtained by inhibition studies.

Binding Sites↗