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Prevention of OKT3 nephrotoxicity after kidney transplantation.

In our experience the use of OKT3 as prophylaxis in renal transplantation has been associated with an increased incidence of both delayed graft function and thromboses of graft vessels. OKT3 nephrotoxicity might have been favored by restriction of perioperative fluid infusion to prevent pulmonary edema and by the use of very high dose (30 mg/kg) of methylprednisolone (mPDS) before the first OKT3 injection to reduce the release of cytokines. This led us to modify our perioperative management in three ways: (1) hydration status was optimalized; (2) the calcium-channel blocker diltiazem, considered beneficial for recovery of graft function, was administered on the day of transplantation; and (3) the dose of mPDS given before the first OKT3 injection was fixed at 8 mg/kg. Comparison of two consecutive series of patients (group 1, control patients, N = 172; group 2, managed as described above, N = 173) showed that: (1) the incidence of delayed graft function fell from 52% in group 1 to 22% in group 2 (P < 0.0001): (2) the incidence of pulmonary edema was not significantly increased in group 2 (3.5% vs. 1.7% in group 1, P = 0.5); and (3) the frequency of intragraft thrombosis fell from 7.6% in group 1 to 1.2% in group 2 (P = 0.0034). Multivariate analysis showed that the volemia/diltiazem program and avoidance of high mPDS dose were the most important factors responsible for the reduced occurrence of delayed graft function and graft vessels thrombosis, respectively. We conclude that a combined strategy of appropriate dosage of steroids before the first OKT3 injection, administration of a calcium-channel blocker and optimalization of volemia is safe and efficiently prevents against OKT3 nephrotoxic effects.

Adult↗

Mechanisms of immunosuppression induced by antithymocyte globulins and OKT3.

OKT3 monoclonal antibody and polyclonal antithymocyte or antilymphocyte globulins are among the most potent immunosuppressive agents which have been used in organ transplantation for many years. Both induce a rapid and profound lymphocytopenia classically attributed to several mechanisms, such as complement-dependent cytolysis, cell-mediated antibody-dependent cytolysis, as well as opsonization and subsequent phagocytosis by macrophages. However, the relative contribution of these three Fc-dependent mechanisms in vivo is difficult to ascertain and may be less important than previously thought. In addition OKT3 induces T-cell receptor modulation in vivo and modulated T cells no longer interact with antigen-presenting cells. Modulation of the T-cell receptor complex has not been documented for antithymocyte and antilymphocyte globulins as yet. The monoclonal antibody OKT3, which is directed against the epsilon chain of the CD3 molecule on the T-cell surface, but also antithymocyte and antilymphocyte globulins, which contain antibodies directed against CD3 and other functional molecules on the surface of T and B cells, generate various transduction signals to the target cells which can affect their functions in different ways. Recent in vitro studies suggest that these antibodies interfere with activation signals. Indeed, antithymocyte and antilymphocyte globulins, at low concentrations, inhibit T-cell activation induced by alloantigens, whereas they induce polyclonal T-cell activation at higher concentrations. Mitogenic antibodies can trigger an activation-induced cell death phenomenon as documented with anti-CD3 antibodies. Anti-CD3 antibodies can also induce a state of specific unresponsiveness (clonal anergy) which may contribute to their long-lasting immunosuppressive effect. One may hypothesize from in vitro data that in spite of their nonspecific immunosuppressive effects which may result in severe iatrogenic immunodeficiency, antilymphocyte antibodies may also act on stimulated alloreactive T-cell clones and therefore contribute to donor-specific graft adaptation.

Antibodies↗

Left ventricular dysfunction after heart transplantation: incidence and role of enhanced immunosuppression.

BACKGROUND: The purpose of this study was to examine the incidence, natural history, and outcome of left ventricular dysfunction in 102 consecutive heart transplant recipients. Left ventricular dysfunction (defined as a decline in the echocardiographic ejection fraction to < 0.45) occurred in 16 of 102 transplant recipients (16%) at a mean of 9.7 +/- 8.6 (standard deviation) months after transplantation. METHODS: Diagnostic evaluation included right heart catheterization and endomyocardial biopsy in all patients and coronary angiography in 13 patients. RESULTS: Four patients were found to have moderate cellular rejection (International Society for Heart and Lung Transplantation grade 2 or higher) and were treated with enhanced immunosuppression. Two patients had angiographically apparent coronary allograft vasculopathy; both died of electromechanical dissociation within 4 months. The remaining ten patients had no or mild cellular rejection (International Society for Heart and Lung Transplantation grade 0 or 1). Therapy in these ten patients included corticosteroids (n = 8). OKT3 (n = 5), and plasmapheresis (n = 2). Three patients died within 2 months of diagnosis, two from undetected severe coronary allograft vasculopathy and one from unrecognized constrictive pericarditis. The echocardiographic ejection fraction improved in the surviving patients after enhanced immunosuppressive therapy (0.33 to 0.53, p < 0.005). With the benefit of long-term clinical follow-up and autopsy data, the origins of left ventricular dysfunction in the 16 patients included moderate cellular rejection (n = 4), vascular rejection (n = 1), coronary allograft vasculopathy (n = 3), intercurrent cytomegalovirus infection (n = 1), constrictive pericarditis (n = 1), and either mild or no evident rejection (n = 6). Survival of the 16 patients with left ventricular dysfunction was similar to that of the 86 patients without left ventricular dysfunction. CONCLUSIONS: The cause of left ventricular dysfunction after heart transplantation includes cellular rejection, vascular rejection, coronary allograft vasculopathy, cytomegalovirus infection, constrictive pericarditis, and unexplained mechanisms. Given the improvement in left ventricular function observed after empiric therapy with enhanced immunosuppression in patients with left ventricular dysfunction, immune-mediated phenomena may play an important pathogenic role.

Biopsy↗

Interdisciplinary development of an intravenous infusion protocol for Orthoclone OKT3.

The development and implementation of an infusion protocol for Orthoclone OKT3 (Ortho Biotech, Inc., Raritan, NJ) is described in this article. OKT3 is a potent immunosuppressant drug used to lower the incidence of graft rejection in transplant patients. Nurses and physicians use the protocol described in this article to administer OKT3 to heart and lung transplant patients at our institution. Pharmacokinetics, along with the nursing care, associated with OKT3 administration are described in the protocol section. The benefits of protocol use are reported in the conclusion.

Humans↗

MUC1-specific targeting immunotherapy with bispecific antibodies: inhibition of xenografted human bile duct carcinoma growth.

For the purpose of establishing a new adoptive immunotherapy for bile duct carcinoma (BDC), we synthesized two bispecific antibodies (BsAbs), MUC1 x CD3 BsAb constructed with MUSE11 (anti-MUC1 tumor antigen) and OKT-3 (anti-CD3), and MUC1 x CD28 BsAb constructed with MUSE11 and 15E8 (anti-CD28) antibodies. These two BsAbs reacted well with both MUC1-positive target tumor cells and effector lymphokine-activated killer (LAK) cells. Investigation of in vitro cytotoxicity [3-(4,5-dimethylthiazo-2-yl)-2,5-diphenyltetrazolium bromide assay] revealed that the MUC1 x CD3 BsAb could antigen-specifically enhance the cytotoxicity of LAK cells. Addition of the two BsAbs (MUC1 x CD3 BsAb plus MUC1 x CD28 BsAb) in vitro resulted in a 60% cytotoxicity, similar to that obtained with BsAb (MUC1 x CD3) alone. Interleukin 12-induced LAK cells demonstrated far greater cytotoxicity (50%) than their interleukin 2-induced counterparts (LAK cells), and this was also enhanced by the BsAbs. When 2 x 10(7) LAK cells sensitized with both kinds of BsAbs were administered four times i.v. to BDC-grafted severe combined immunodeficient mice (tumor size 5 mm in diameter), inhibition of tumor growth was observed. Thus, BsAb-LAK therapy for control of BDC warrants clinical trials.

Animals↗

Methotrexate for rejection prophylaxis after heart transplantation.

BACKGROUND: The addition of vincristine to "quadruple-drug" induction immunotherapy (OKT3, cyclosporine, azathioprine, prednisone) after heart transplantation decreases the incidence of rejection but is limited by neurotoxicity. We hypothesized that methotrexate, when added to quadruple therapy, may also decrease the incidence of rejection but with less toxicity. METHODS: We randomized 36 heart transplant recipients to receive either quadruple therapy (OKT3, cyclosporine, azathioprine, corticosteroids) (n = 19) or quadruple therapy plus methotrexate (n = 17). Methotrexate was given weekly for 8 weeks beginning at the conclusion of OKT3 therapy (postoperative days 8 to 16), and dosed according to white blood cell count. RESULTS: Six methotrexate patients did not complete the protocol, leaving 11 patients on weekly methotrexate at a mean dose of 8.6 mg/week (range 0 to 15 mg/wk). Multiple indexes of rejection were similar between the two groups, including days to first rejection, number of treated rejection episodes, mean biopsy scores, and number of patients requiring intravenous corticosteroids or antilymphocyte therapy. Toxicity and infection rates were not significantly different between the two groups. CONCLUSIONS: Although toxicity was minimal, an 8-week course of methotrexate appears to add no significant benefit to quadruple-drug immunotherapy.

Azathioprine↗

CD40L is important for induction of, but not response to, costimulatory activity. ICAM-1 as the second costimulatory molecule rapidly up-regulated by CD40L.

The CD40 ligand (CD40L):CD40 interaction plays an important role in the activation of both T and B cells. However, the mechanisms by which this interaction is involved in activation of T cells is still unclear. Here we show that CD40L is not essential for T cell response to TCR engagement if the APC have costimulatory activity, although it is essential for T cell-mediated induction of such costimulatory activity. To determine the molecular basis of this activity, we have produced three mAbs that appear to recognize the costimulatory molecules rapidly induced by CD40L. Two of them recognize CD44H, which we showed to have CD28-independent costimulatory activity for T cells. The molecule recognized by the remaining mAb is hereby identified as ICAM-1. Furthermore, ICAM-1-mediated costimulation is likely to serve for a function similar to that mediated by the B7:CD28 interaction, as targeted mutation of CD28 renders T cell responses to Con A more dependent on ICAM-1.

Animals↗

Antilymphocyte induction immunosuppression in the post-Minnesota anti-lymphocyte globulin era: incidence of renal dysfunction and delayed graft function. A single center experience.

Between 4/91 and 12/93, 262 patients received cadaveric (CRT) (n = 205) or living donor (LRT) (non-HLA identical) renal transplants. All patients were treated with the same sequential induction immunosuppression protocol, with the exception of different forms of antilymphocyte sera: either Minnesota antilymphocyte globulin (MALG), antithymocyte globulin (ATG), orthoclone antibody (OKT3), d 1 postoperatively, or OKT3 intraoperatively. With the withdrawal of MALG from the market, we wished to prospectively analyze the influence of these other antilymphocyte therapies on the incidence of delayed graft function (DGF) (the requirement for hemodialysis within the first week postoperatively) and renal function during the first 3 d postoperatively and during the subsequent .6 months post-transplantation and compare that with our MALG experience. Of the 205 CRT, 76 received MALG with a DGF rate of 18.4%, 50 received ATGAM with a DGF rate of 22.0%, 38 received OKT3 postoperatively with a DGF rate of 39.5%, and 41 received OKT3 intraoperatively with a DGF rate of 39%. Of the 57 LRT, only two patients, one receiving intraoperatively OKT3 (secondary to graft thrombosis), and one MALG patient, suffered DGF. Serum creatinine values were obtained from postoperative d 1 through postoperative d 4 for 185 patients. Each of the four groups showed similar mean decrements in serum creatinine. The number of grafts functioning at 1, 2, 3 and 6 months postoperatively and serum creatinine values were not statistically different between the groups. We conclude that induction immunosuppression with MALG and ATGAM is associated with a lower DGF rate than OKT3 given either intraoperatively or postoperatively. However, with 6 months of follow-up, we do not observe any difference in the incidence of rejection or graft function between the therapies. Consequently, we have chosen ATGAM as our preferred inductive therapy in the absence of MALG owing to its lower associated DGF rate.

Adult↗

Incidence of post-transplant malignancy among 674 solid-organ-transplant recipients at a single center.

We evaluated the post-transplant course of the entire solid-organ-transplant population at our institution to determine the frequency, incidence and specific type of post-transplant malignancies which occurred at a single center. Of 674 solid-organ-transplant recipients (305 renal, 307 heart, 54 lung, 8 heart/lung), we detected 79 malignancies (48 heart, 28 renal, 2 lung, 1 heart/lung), representing an overall cancer frequency of 11.7%, 15.6% for heart and 9.2% for renal transplant recipients. The frequency in both transplant groups was higher than that reported previously in the multicenter data in the literature (about 6%); we also noted a shorter interval to malignancy (27 vs. 61 months). The most common malignancies overall were skin/lip carcinomas and post-transplant lymphoproliferative disorder (PTLD). The frequency of PTLD was higher in non-renal (6.5%) than renal (0.7%) transplant recipients and statistical analysis confirmed a significant higher incidence of all malignancies (p = 0.0032) and of PTLD (p = 0.0001) in heart and lung recipients as opposed to renal transplant recipients. The frequency of total skin/lip carcinomas was essentially equal in the heart and renal transplant groups (6%), and statistical analysis showed no significant difference in incidence of this general type of malignancy; however, there was a marked disparity in interval to squamous cell carcinoma (SCC) between renal and heart transplant recipients (27 versus 59 months). This was associated with an apparent increase in the rate of occurence of SCC after 60 months in heart transplant recipients, a finding not previously reported in the multicenter data in the literature. We did not demonstrate a significant effect of the withdrawal of prophylactic OKT3 from the immunosuppression regimen of heart transplant recipients on the incidence of all tumors, PTLD or skin/lip tumors.

Aged↗

Effect of oral pentoxyfylline on the OKT3-induced cytokine-release syndrome among renal allograft recipients.

Recent data suggest that pentoxyfylline administration results in a significant reduction in serum TNF levels among OKT3-treated patients. However, the effect of pentoxyfylline on the clinical syndrome that ensues following OKT3 administration remains undefined. We evaluated 32 OKT3-treated renal transplant recipients to assess the impact of pentoxyfylline on OKT3 adverse reactions. The study population consisted of two groups: (i) a prospective group comprising 16 patients who received oral pentoxyfylline 600 mg 1-2 h prior to the first dose of OKT3 and then 600 mg every 8 h for 72 h, in addition to corticosteroids, acetaminophen and diphenhydramine, and (ii) an historical control group (n = 16) treated with corticosteroids, acetaminophen and diphenhydramine alone. All patients were evaluated for signs and symptoms consistent with the OKT3-induced cytokine-release syndrome. The incidence and clinical severity of OKT3-related adverse reactions were similar among the two groups. We conclude that oral administration of pentoxyfylline does not appear to affect the incidence or severity of OKT3-related adverse reactions.

Administration, Oral↗

Treatment of renal allograft acute rejection with methylprednisolone: effect of fixed dose versus dose per body mass index.

Considerable interpatient variability in steroid pharmacokinetics has been observed in renal transplant recipients. The purpose of this retrospective study is to evaluate the relationship between the dose of methylprednisolone (MP) used to treat acute rejection (AR) after renal transplantation and the response to treatment. 117 first AR episodes from 408 renal transplants were reviewed. The dose of MP used to treat AR was < 45 mg/kg/m2 in 60 patients and > and = 45 mg/kg/m2 in 57 patients. The correlation between fixed dose ( < 1.25 vs. > and = 1.25 g) and dose based on BMI was evaluated by simple linear regression analysis (r2 = 0.78, p < 0.0005). Response to treatment was as follows: MP successful (Group 1, n = 80); MP failed, OKT3 successful (Group 2, n = 17); MP and OKT3 failed (Group 3, n = 3) and MP failed, no further treatment (n = 17). No relationship was observed between the dose of MP, whether fixed or based on BMI, and (1) response to treatment of the first AR, (2) incidence of a second AR and (3) response to subsequent treatment with OKT3. Actuarial graft survival was higher in Group 1 compared to Group 2 (p < 0.0005), lower in Black recipients (p = 0.02) and higher when > and = 45 mg/kg/m2 of MP was used to treat AR (p = 0.06). In conclusion, no relationship between the dose of MP, whether fixed or based on BMI, and the response to treatment of AR was observed. MP dosage based on BMI may be a reasonable alternative to a fixed-dose regimen with the advantage of limiting steroid exposure and the consequent side-effects.

Acute Disease↗

Regulation of gamma T-cell antigen receptor expression by intracellular calcium in acute lymphoblastic leukemia cell line DND41.

The calcium ionophore, ionomycin, promotes an increase of intracellular calcium and regulates mRNA expression of gamma/delta-TcR gene in human T lymphocytes. The mechanism of this regulation is not yet clear. Thus, the regulation by intracellular calcium requires elucidation. We studied the gamma-TcR gene expression in acute lymphoblastic leukemia cell line DND41 (CD4- CD8-) by Northern blot and flow cytometric analysis. The mRNA levels of gamma-TcR increased by ionomycin, anti-CD3, and with TPA. TPA had an antagonistic effect to both ionomycin and anti-CD3. Also, TPA inhibits the increased intracellular calcium promoted by ionomycin but not the increase promoted by anti-CD3 and ionomycin. Our results suggest that intracellular calcium induces mRNA and protein expression of gamma-TcR chain. This effect is antagonized by protein kinase C-activation. Thus, we conclude that the target cells of the differential regulation on gamma-TcR mRNA expression by intracellular calcium modulators are the CD4- CD8- cells, and this is due to cytosolic calcium mobilization.

Calcium↗

Increased dermal expression of ICAM-1 and VCAM-1 after administration of OKT3 in man.

OKT3 induces a systemic release of cytokines and a profound peripheral lymphocytopenia. In vitro, tumor necrosis factor-alpha, interleukin-1, and interferon-gamma increase adhesion molecule expression on vascular endothelium. To investigate the effects of OKT3 induced cytokine release on endothelial- and lymphocyte adhesion molecule expression in vivo, we studied sequential skin biopsies of six renal allograft recipients treated for acute rejection with 5 mg OKT3. An additional group of six patients treated for acute rejection with 50 mg methylprednisolone served as a control group. Compared to pre-treatment biopsies, biopsies taken 4.5- and 24 hours after the first OKT3 dose showed a maximal increase in VCAM-1 and ICAM-1 expression, respectively. In parallel, an increased number of CD2+, CD11a+, and CD49d+ mononuclear cells in the skin was observed in all OKT3 treated patients. No changes were observed after methylprednisolone treatment. We conclude that the OKT3 induced cytokine release induces increased ICAM-1- and VCAM-1 expression on vascular endothelium, leading to increased influx of CD2+ lymphocytes which may contribute to the peripheral lymphocytopenia after OKT3.

Acute Disease↗