Search PubMed⌕ Search

Biomedical subjects

L Chatenoud

Publications and source records attributed to L Chatenoud.

At least 199 records · Page 11Linked to original sources
PubMed1987

Effects of cyclosporine in severe systemic lupus erythematosus.

Thirteen patients with severe steroid-resistant or steroid-dependent forms of systemic lupus erythematosus were treated with cyclosporine (average dose 5 mg/kg/d) for an average period of 12 months. In eight patients the disease activity decreased, as substantiated by the reduction in the amount of steroid required to control the clinical manifestations. Interruption of cyclosporine treatment was associated with relapse or worsening of disease in five subjects. These favorable clinical results occurred in the absence of changes in the levels of antinuclear, anti-double-stranded deoxyribonucleic acid autoantibodies or plasma complement components; plasma IgG concentration increased significantly. Six patients had signs of moderate cyclosporine nephrotoxicity that disappeared when the administration of the drug was discontinued. Hypertension was the most serious side effect observed in eight subjects; in every case it was controlled by antihypertensive medicine. These data indicate that cyclosporine may be beneficial in the treatment of some patients with severe forms of systemic lupus erythematosus.

Adolescent↗
PubMed1987

Frequent lymphocytes infection by hepatitis B virus in haemophiliacs.

We have tested the different mononuclear blood cell populations of seven patients with severe haemophilia and one patient with F VII deficiency for the presence of HBV DNA. These subjects were all polytransfused with non-heated coagulation factors; three were HBsAg positive, five HBsAg negative but anti-HBc and anti-HBs positive; HBV DNA sequences were detected in six subjects including three without detectable serum HBsAg. Furthermore the viral DNA sequences were identified in the T lymphocyte subpopulations (OKT4+ and/or OKT8+ cells). This observation suggests that HBV infection of lymphocytes might be related to the immunological disorders observed in these patients.

Blood Coagulation Factors↗
PubMed1987

[Preventive treatment of rejection by the prolonged administration of OKT3: decrease of the immune response of the host].

Clinical use of OKT3 for the treatment of ongoing rejection episodes has already been demonstrated as being highly effective. This work shows for the first time that combining azathioprine and OKT3 was able to delay as well as to decrease both the intensity and the quality of the anti-OKT3 immunization, allowing a 1-month prophylactic use of the MoAb. It also proves that OKT3 used prophylactically during one month can lead to 4-year first cadaver graft and patient survival rates better than those ever reported with any other immunosuppressive regimen. These results were obtained with lower doses of steroids and other immunosuppressive agents than in conventionally treated control patients. After the first two injections of OKT3, tolerance was perfect allowing out-hospital administration, and side effects consisted only in an increased number of viral infections instead of the bacterial infections observed in the conventional treatment groups. The prophylactic use of OKT3 should give even better results if it were possible to reach a 1-month administration schedule in all patients by modulating the dose of OKT3 according to the T3+ cell count and the monitoring of serum OKT3 levels.

Antibodies, Monoclonal↗
PubMed1987

[In vivo use of OKT3 monoclonal antibodies in recipients of renal allografts].

The OKT3 monoclonal antibody, that is specific for all mature human T lymphocytes represents a potent immunosuppressant when injected in vivo. The OKT3 antibody has been administered to more than 500 renal allograft recipients either to treat or prevent acute rejection episodes. OKT3 exerts its immunosuppressive effect by inducing rapid and important T cell depletion following the first injection. Then, OKT3 mediates the antigenic modulation of its T cell target antigen a phenomenon that is also related to the immunosuppressive effect exerted by the monoclonal antibody. The principal side effect observed following OKT3 administration, particularly if the antibody is injected alone, is the xenosensitisation against the foreign protein. Essentially, two sorts of anti-OKT3 antibodies are produced that respectively recognize the isotypic and the idiotypic determinants of the antibody molecule. The different strategies that may be envisaged to overcome this important side effect, that may totally neutralize the therapeutic effectiveness of OKT3 are discussed in detail.

Antibodies, Monoclonal↗
PubMed1986

Restriction of the human in vivo immune response against the mouse monoclonal antibody OKT3.

The murine monoclonal antibody OKT3 (IgG2a) was administered prophylactically to 17 renal allograft recipients (5 mg/day, i.v.), either alone or in association with corticosteroids (0.25 mg/kg/day) and azathioprine (3 mg/kg/day). In all patients the kinetics of the IgM and IgG anti-OKT3 response was monitored by means of immunofluorescence and ELISA. All patients treated with OKT3 alone showed a rapid and strong sensitization that completely neutralized the therapeutic effectiveness of the monoclonal antibody. The anti-OKT3 sensitization was manifested by accelerated OKT3 clearance and abrupt reappearance of circulating OKT3+ cells before the end of treatment. This immune response was significantly delayed and reduced in its incidence and intensity in patients receiving low dose corticosteroids and azathioprine in association to OKT3; mainly IgM anti-OKT3 antibodies that did not accelerate OKT3 clearance were then observed. The fine specificity of the antibodies produced was studied, using patients whole sera and various mouse IgG2a-affinity chromatography-purified serum fractions. The results obtained showed that the anti-OKT3 response was remarkably restricted to two main categories of antibodies: a) anti-idiotypic antibodies that inhibited OKT3 binding to T cells and abrogated its therapeutic activity and b) anti-mouse IgG2a (anti-isotypic) antibodies that did not neutralize OKT3 immunosuppressive activity. These results suggest that OKT3-immunized patients might still be sensitive to the immunosuppressive effect of other anti-T cell monoclonals that do not share the OKT3 idiotype and possibly isotype.

Animals↗
PubMed1986

The human immune response to the OKT3 monoclonal antibody is oligoclonal.

The availability of highly specific and homogeneous antibodies to human T cells by the hybridoma technique has elicited new interest in the clinical use of antibodies to lymphocytes as immunosuppressive agents. OKT3 is the murine monoclonal antibody that has been the most widely used in clinical transplantation to induce immunosuppression. This antibody recognizes a membrane molecular complex, exclusively present on mature human T lymphocytes, which is tightly linked to the T-cell antigen receptor. The long-term therapeutic use of murine monoclonal antibodies in vivo is hampered by the intense antibody response that occurs in most human patients. Thus, when administered alone, OKT3 manifests its immunosuppressive activity only during the 10 to 15 days that precede the onset of sensitization. The results presented here show, by use of isoelectrofocusing, that the antibody response to OKT3, already reported to be restricted in its specificity (only anti-isotypic and anti-idiotypic antibodies are produced), is in addition oligoclonal. This restriction of the anti-monoclonal response may suggest that an efficient way to circumvent the sensitization problem would be to administer consecutively different monoclonal antibodies presenting the same specificity but distinct idiotypes.

Antibodies, Monoclonal↗
PubMed1986

Fine specificity of antibodies produced in rhesus monkeys following in vivo treatment with anti-T cell murine monoclonal antibodies.

The immune response of 23 rhesus monkeys against different murine monoclonal antibodies (mAb) administered in vivo as immunosuppressive agents has been analyzed. Seven mAb specific for either helper-inducer (CD4 molecules) or cytotoxic/suppressor (CD8 molecules) T cells, that cross-react with monkey lymphocytes, were administered i.v. for 10 consecutive days in rhesus monkeys. Nineteen of the animals were recipients of a skin or renal allotransplant. Nineteen out of the 23 monkeys developed a significant immune response against the injected monoclonal. This response was restricted in its specificity since unrelated murine monoclonals were not recognized by the monkeys' anti-monoclonal immunoglobulins. Fine analysis of the monkeys' sera revealed that the antibodies produced against the xenogeneic proteins selectively exhibited two major specificities i.e., anti-isotypic and anti-idiotypic. On a practical basis, these results suggest that an animal already immunized against a given mAb should still be sensitive to the therapeutic effect of another monoclonal sharing the same specificity but different idiotype.

Animals↗
PubMed1986

Hepatitis B virus DNA in mononuclear blood cells. A frequent event in hepatitis B surface antigen-positive and -negative patients with acute and chronic liver disease.

We have investigated 38 hepatitis B surface antigen (HBsAg)-positive and 34-negative patients with acute and chronic liver disease for the presence of hepatitis B virus (HBV) DNA in peripheral mononuclear blood cells. Among the HBsAg-positive subjects HBV DNA was detected in the mononuclear cells of asymptomatic HBV carriers (2/6), patients with acute hepatitis (8/8), chronic active hepatitis (18/21), and with hepatocellular carcinoma (2/3); the viral DNA sequences were also identified in the mononuclear cells of patients with HBsAg-negative acute hepatitis (2/3), chronic active hepatitis (5/15) and hepatocellular carcinoma (5/16), some of these showing no evidence of HBV by conventional serological markers. By contrast HBV DNA was not detected after resolution of the acute viral infection. For 7 patients different mononuclear cell-enriched subpopulations were assayed and the viral DNA was observed in T lymphocytes (both OKT4+ and OKT8+ enriched subsets) and/or in B enriched lymphocytes; the restriction DNA patterns showed in some patients a genetic organisation of the viral DNA similar to those observed in the liver (including free monomeric and oligomeric HBV DNA and results consistent with integrated viral sequences); however, no HBV DNA replicative forms were detected. These results show that the hepatitis B virus infection of mononuclear blood cells (including lymphoid cells) is a frequent event at all stages of the viral infection which might be related to immunological abnormalities observed in HBV carriers; in addition the mononuclear blood cells analysis may provide an insight to the liver cells status.

B-Lymphocytes↗
PubMed1986

Presence of preactivated T cells in hemodialyzed patients: their possible role in altered immunity.

Interleukin 2 (IL-2) and B-cell growth factors I and II (BCGF I and BCGF II) are lymphokines produced by T cells that play a major role in T- and B-cell cooperation. Peripheral blood lymphocytes from 12 uremic patients undergoing intermittent hemodialysis were tested for their capacity to produce IL-2 and BCGFs and to respond to these soluble mediators. IL-2 and BCGF activities were determined by means of two biological assays (proliferation of IL-2-dependent cytotoxic T-cell line CTLL-2 and of anti-human IgM (mu chain)-stimulated normal B cells, respectively) in the supernatants of phytohemagglutinin A-stimulated T-cell cultures. IL-2 activity was significantly decreased in patients as compared to normal controls (mean +/- SEM, 0.28 +/- 0.09 unit per ml) in hemodialyzed patients versus 1.02 +/- 0.16 units per ml in normal controls). This profound abnormality contrasted with the normal activity of the BCGFs that was invariably observed in the same supernatants. A similar dissociation was detected when analyzing the sensitivity of uremic B and T cells to exogenous purified lymphokines. Anti-IgM (mu chain)-stimulated uremic B cells exhibited a normal response to recombinant IL-2 and to chromatography-purified BCGF I and BCGF II. Resting B cells did not show any increased reactivity to these lymphokines. In contrast, whereas in normal controls recombinant IL-2 exclusively induced the proliferation of T cells that had been previously activated by a mitogen, resting T cells from uremic patients were highly responsive to exogenous IL-2. This abnormal response was paralleled by significantly increased proportions of peripheral T cells recognized by the anti-Tac monoclonal antibody that specifically binds to the IL-2 receptor. These data clearly show the existence in hemodialyzed patients of abnormally high proportions of T cells presenting phenotypic and functional signs of preactivation. This increased T-cell IL-2 receptor expression may offer an explanation to the deficient IL-2 activity observed in patients' supernatants (by inducing increased absorption of the lymphokine). The potential relevance of these preactivated T cells to the depressed cell-mediated immunity observed in hemodialyzed patients is outlined.

Adult↗
PubMed1986

Prophylactic use of OKT3 monoclonal antibody in cadaver kidney recipients. Utilization of OKT3 as the sole immunosuppressive agent.

We describe the first clinical trial of OKT3, a monoclonal anti-T-cell antibody, for prevention of kidney transplant rejection. 13 patients receiving a first cadaveric kidney transplant were randomly assigned to conventional treatment with azathioprine and high-dose steroids (7 patients) or to treatment with daily injection of OKT3 alone (6 patients). The first OKT3 injection resulted in a dramatic decrease in T3+, T4+, and T8+ cells, while patients simultaneously experienced fever, chills, and diarrhea. These symptoms did not recur with subsequent injections. All six OKT3-treated patients had a rejection necessitating introduction of steroids 12.8 +/- 2.9 days after surgery. Rejection was related to appearance of anti-OKT3 antibodies leading to disappearance of detectable OKT3 in the serum. Modulating (T3-, T4+ or T3-, T8+) cells were observed in all patients but were functionally inactive. As no rejection was observed before day 9 posttransplant, despite the lack of additional immunosuppressive agents, we conclude that OKT3 is a powerful, well-tolerated immunosuppressive agent. However, it is highly immunogenic and anti-OKT3 antibodies lead to loss of clinical effectiveness in this protocol. The use of OKT3 alone for prevention of kidney graft rejection cannot be recommended until a method for reducing the effects of anti-OKT3 immunization is developed.

Acute Disease↗
PubMed1985

[Present and future value of monoclonal antibodies in nephrology].

Many monoclonal antibodies directed against human T-lymphocytes have been produced in mice. Some of these, such as OKT 3, recognize all T-cells which can thus be counted in the blood; they have been used for the prevention of renal transplant rejection. Despite unexpected problems, such as antigenic modulation and anti-mouse sensitization, the first results obtained are promising. Other antibodies produced are directed against T-lymphocyte subsets, notably T-helpers (OKT4+) and T-suppressors or cytotoxic T-cells (OKT8+). Studies of the OKT4+/OKT8+ ratio have shown an imbalance in T-cell subsets in 2 types of glomerulonephritis: Berger's disease and membranous glomerulonephritis; they have also contributed to a better understanding of renal allograft rejection, where this ratio is often elevated.

Animals↗
PubMed1985

Metabolic and immunological effects of cyclosporin in recently diagnosed type 1 diabetes mellitus.

Cyclosporin 5-10 mg/kg daily was given for 2-8 months to twelve recently diagnosed type 1 diabetics from a mean of 49 +/- SE 14 days after the start of insulin therapy, which was regulated to give near-normal blood glucose and haemoglobin A1c values. Mean insulin dosage dropped from 46 +/- 5 U/day before cyclosporin treatment to 16 +/- 4 U/day by the 7th month. Four patients had a complete remission and the insulin needs of four more were cut by half. The remaining four did not have remissions. Initial basal and glucagon-stimulated C peptide concentrations were higher in those who went into remission than in those who did not; they rose during cyclosporin treatment in the former but not in the latter. OKT4+ lymphocyte functions were suppressed in all patients and OKT4/OKT8 ratios declined. Anti-beta-cell autoimmunity, as indicated by lymphocyte-induced inhibition of insulin release from mouse islet cells, declined in all patients who went into remission. No consistent trend was observed for anti-islet cell antibodies. In forty-four similar, but non-randomised, recently diagnosed diabetics treated with insulin alone, the incidence of remission was 6%.

Adult↗