摘要:

The influence of granulocyte-macrophage colony-stimulating factor (GM-CSF) and the recently identified hematopoietic stem-progenitor cell mobilizing factor flt3 ligand (FL) on donor leukocyte microchimerism in noncytodepleted recipients of allogeneic bone marrow (BM) was compared. B10 mice (H2b) given 50×106allogeneic (B10.BR [H2k]) BM cells also received either GM-CSF (4 μg/day s.c.), FL (10 μg/day i.p.), or no cytokine, with or without concomitant tacrolimus (formerly FK506; 2 mg/kg) from day 0. Chimerism was quantitated in the spleen 7 days after transplantation by both polymerase chain reaction (donor DNA [major histocompatibility complex class II; I-Ek]) and immunohistochemical (donor [I-Ek+] cell) analyses. Whereas GM-CSF alone significantly augmented (fivefold) the level of donor DNA in recipients' spleens, FL alone caused a significant (60%) reduction. Donor DNA was increased 10-fold by tacrolimus alone, whereas coadministration of GM-CSF and tacrolimus resulted in a greater than additive effect (28-fold increase). A much more striking effect was observed with FL + tacrolimus (>125-fold increase in donor DNA compared with BM alone). These findings were reflected in the relative numbers of donor major histocompatibility complex class II+cells (many resembling dendritic cells) detected in spleens, although quantitative differences among the groups were less pronounced. Evaluation of cytotoxic T lymphocyte generation by BM recipients' spleen cells revealed that FL alone augmented antidonor immunity and that this was reversed by tacrolimus. Thus, although FL may potentiate antidonor reactivity in nonimmunosuppressed, allogeneic BM recipients, it exhibits potent chimerism-enhancing activity when coadministered with recipient immunosuppressive therapy. This property of FL may offer considerable potential for the augmentation of microchimerism, with therapeutic implications for organ allograft survival and tolerance induction.

ISSN:0041-1337    

出版商:OVID    

年代:1997

数据来源: OVID

摘要:

Lymphoreticular malignancies, collectively called posttransplant lymphoproliferative disorders (PTLD), eventually develop in 2-5% of organ transplant recipients. They frequently undergo regression when immunosuppression is reduced or stopped. This feature has been associated with a previous or de novo Epstein-Barr virus (EBV) infection. We herein describe immunotherapy with autologous lymphokine-activated killer (LAK) cells in seven patients with PTLD (four EBV-positive patients and three EBV-negative patients). Autologous peripheral blood mononuclear cells were obtained by leukapheresis, depleted of monocytes, and cultured in the presence of interleukin 2 for 10 to 11 days. A single dose of 5.2×109to 5.6×1010LAK cells was given intravenously. Systemic interleukin 2 was not administered.The four patients with EBV+PTLD had complete tumor regression; two of them developed controllable rejection. Three patients are well 13-16 months after treatment; the fourth patient died of pneumonia 41 days after infusion. Three patients with EBV-lymphomas had no response despite prior evidence that their tumors also were subject to immune surveillance. Two of these three patients died after being given other treatment, and the third patient has persistent tumor.In conclusion, autologous LAK cell infusion was effective for treatment of four EBV+organ transplant recipients. LAK cell efficacy for three patients with EBV-PTLD was not evaluable under the management circumstances in which this treatment was utilized.

ISSN:0041-1337    

出版商:OVID    

年代:1997

数据来源: OVID

摘要:

Hepatocyte allotransplantation has been performed successfully in several small animal models for the amelioration of inborn metabolic errors. Before a human clinical trial of hepatocyte allotransplantation can be attempted, preliminary experience in a large animal model is needed. We transplanted isolated mongrel hepatocytes into the spleen of dalmatians in the attempt to cure their inborn error of uric acid metabolism. Of 10 dalmatian recipients, two that received 9-10×109mongrel hepatocytes died early after surgery of acute portal hypertension and hemorrhage. The eight long-term survivors received 5-6×109hepatocytes and were randomized either to no treatment or to oral cyclosporine (CsA). Levels of CsA were adjusted to maintain trough levels between 400 and 800 ng/ml. In the four nonimmunosuppressed dalmatians, a reproducible average reduction in urinary uric acid excretion (UUAEx) of 23.7% was achieved; values returned to baseline within 14 days. In the CsA-immunosuppressed dalmatians, the average decline in UUAEx was 30%. The partial correction of the metabolic defect persisted for an average of 25 days in three immunosuppressed dogs, whereas in one dog, the partial correction lasted for over 90 days. No change in UUAEx was observed in two dalmatians that underwent sham laparotomy and intrasplenic injection of saline solution; CsA given alone to dalmatians did not modify UUAEx. We conclude that the dalmatian dog is a valuable large animal model for studies of the role of hepatocyte transplantation in the cure of inborn hepatic metabolic errors.

ISSN:0041-1337    

出版商:OVID    

年代:1997

数据来源: OVID

摘要:

Background.The immunogenicity of nerve allografts is responsible for their rejection. We have developed a method for preparing cell-free nerve grafts using lysophosphatidylcholine to remove cells, axons, and myelin sheaths.Methods.The remaining intact nerve extracellular matrix is the extracted nerve graft (eNG). Cultured neonatal Schwann cells were micro-injected into the eNG to form recellularized nerve grafts (rNG). eNG, rNG, and normal isografts (15 mm long) were implanted in the peroneal nerves of F-344 rats. Ten rats were given an eNG on the right, and an isograft on the left. Ten rats were given an rNG on the right, and a sham operation on the left. Sham operation was used as the control and the isograft was used as the benchmark procedure. Walking track analysis was performed every 15 days after surgery to determine the peroneal functional index. Morphometric analysis of the distal peroneal nerve and extensor digitorum muscle weight were analyzed 3 months after surgery.Results.The three types of grafted legs had the classical effect observed after peripheral nerve repair, with decreased functional ability, decreased target muscle weight, fewer large nerve fibers, and more small nerve fibers. Isografts, eNG, and rNG all had similar patterns of peroneal functional index improvement after implantation. The extensor digitorum longus muscle weight and axon counts for the three types of graft were not statistically different. Hence, eNG and rNG can enhance nerve regeneration in the same way as isografts. The host Schwann cells that invaded the implanted eNG probably acted in the same fashion as the cultured Schwann cells injected into the rNG and the resident cells of isografts.Conclusions.The great permeability of the longitudinally oriented matrix of eNG to cells is, therefore, a major advantage over the reported poor permeability of freeze-thawed nerve grafts.

ISSN:0041-1337    

出版商:OVID    

年代:1997

数据来源: OVID

摘要:

Background.Cyclosporine (CsA)-induced nephrotoxicity may be due to intrarenal vasoconstriction and glomerular hypoperfusion. Several factors, including endothelin and prostanoids, are suggested mediators of this response. Recent evidence suggests that CsA leads to increased oxygen-derived free radical (ODFR) production and lipid peroxidation in renal tissue. Whether this leads to alterations in renal vessel reactivity is unclear. Lazaroids, such as U74389G, are radical-quenching antioxidants that inhibit ODFR-induced lipid peroxidation and may improve renal function after ischemia and reperfusion. We hypothesized that ODFRs contribute to CsA-induced alterations of the renal microcirculation.Methods.Rat hydronephrotic kidneys were studied by video microscopy. Interlobular arteriolar diameter and flow, afferent and efferent arteriolar diameters, and cardiac output were measured at 15-min intervals for 120 min. U74389G or its vehicle was infused 15 min before topical application of CsA to the kidney. The results were compared with U74389G alone and normal saline.Results.CsA administration caused renal microvascular vasoconstriction (10-25% below baseline) and hypoperfusion (35% below baseline). Both vasoconstriction and hypoperfusion were significantly attenuated by U74389G (5-8% and 20% below baseline, respectively).Conclusions.Inhibition of lipid peroxidation by U74389G maintained renal blood flow during acute CsA administration. These data suggest that ODFRs are involved in the renal microvascular response to CsA. Inhibition of ODFR-induced lipid peroxidation may help prevent CsA-induced glomerular hypoperfusion. Lazaroids may prove an effective adjunct in reducing CsA-induced nephrotoxicity.

ISSN:0041-1337    

出版商:OVID    

年代:1997

数据来源: OVID

摘要:

Background.The requirement for potent systemic immunosuppression to prevent intestinal graft rejection has resulted in high rates of infection and posttransplant lymphoproliferative disease. Budesonide (BUD) is a locally acting steroid that is almost completely metabolized during its first pass through the intestinal wall and liver. The present study examined whether BUD could prevent small bowel allograft rejection without causing the adverse systemic effects associated with prednisolone.Methods.Orthotopic Brown Norway to Lewis rat small bowel allotransplants were randomly assigned to treatment with low-dose BUD (0.1 mg/kg/day, p.o.) and high-dose BUD (1.0 mg/kg/day, p.o.) with and without cyclosporine (CsA; 2 mg/kg/day s.c.). The following parameters were assessed: allograft survival, recipient plasma adrenocorticotrophic hormone (ACTH) levels, recipient adrenal, splenic and thymic weights, recipient CsA levels, and graft histopathology.Results.Low- and high-dose BUD alone did not prolong graft survival compared with the untreated group (9.1±0.4 days vs. 11±0.8 days vs. 9.7±0.4 days, respectively). However, when low-dose BUD and high-dose BUD were given in combination with CsA, the mean graft survival times were prolonged to 27.6±5.3 and 36.6±8.0 days, respectively (P<0.01). ACTH levels, adrenal weights, and thymic weights were not significantly different in the treatment and control groups receiving intestinal transplants.Conclusions.BUD enhances the immunosuppressive effects of CsA and prolongs small bowel allograft survival in rats without inhibiting normal ACTH release. These data suggest that BUD may be a useful immunosuppressive agent for clinical intestinal transplantation.

ISSN:0041-1337    

出版商:OVID    

年代:1997

数据来源: OVID

摘要:

Background.The release of liver arginase after orthotopic liver transplantation (OLT) causes a deficiency of L-arginine and nitrite in the plasma. This deficiency is possibly related to pulmonary hypertension and reduced hepatic blood flow, which are commonly observed in the immediate reperfusion period. The aim of this study was to evaluate the impact of L-arginine supplementation on metabolic and hemodynamic parameters during liver reperfusion after OLT in pigs.Methods.Thirteen pig OLTs (control group, n=6; arginine group, n=7) were performed by a standard technique. Cold ischemic time was 20 hr. L-Arginine was infused at a dosage of 500 mg/kg body weight into the donor pigs (30 min before liver explantation) and also into the recipients (over a period of 3 hr from the beginning of the reperfusion period). At the end of the experimental study, the pigs were killed with an over-dose of potassium.Results.In the control group, liver revascularization increased plasma arginase concentrations (+615%) and reduced plasma levels of L-arginine (-87%), nitrite (-82%), and nitrate (-53%). Infusion of L-arginine increased plasma levels of L-arginine from 94±21 μmol/L to 1674±252 μmol/L (P<0.001), L-ornithine from 46±8 μmol/L to 2215±465 μmol/L (P<0.001), and L-citrulline from 58±8 μmol/L to 116±34 μmol/L (P<0.001), but had no effect on plasma levels of nitrite and nitrate. Administration of L-arginine in the donor pigs did not produce any systemic or organ-specific hemodynamic alterations. Infusion of L-arginine into the recipient pigs improved cardiac performance (increase in heart rate [+61%,P=0.017] and cardiac index [+53%,P=0.005], reduction in pulmonary capillary wedge pressure [-54%,P=0.014]). Moreover L-arginine infusion increased oxygen consumption (+65%,P=0.003), reduced pulmonary vascular resistance index (P=0.001), stimulated portal venous blood flow (P=0.014), and elevated body temperature during the reperfusion period (P=0.007).Conclusions.From these data, we conclude that the infusion of L-arginine during OLT improves the hemodynamic performance of the heart, lung, and liver.

ISSN:0041-1337    

出版商:OVID    

年代:1997

数据来源: OVID

摘要:

Background.Morphological characteristics of islet xenograft rejection differ from those of islet allograft rejection. Therefore, prevention of islet xenograft rejection probably requires a different type of immunosuppression from that used in allogeneic transplantation.Methods.Fetal porcine islet-like cell clusters (ICC) were transplanted into the renal subcapsular space of rats treated with different immunosuppressive protocols. The existence of a cellular infiltrate or deposits of antibodies and complement in the grafts was evaluated at different times after transplantation using immunohistochemistry.Results.Treatment with leflunomide (LEF), cyclosporine (CsA), mycophenolate mofetil (MMF), 15-deoxyspergualin, and rapamycin alone or in combination had an insufficient inhibitory effect on ICC xenograft rejection. However, in animals treated with LEF+CsA, the rejection process was markedly inhibited. However, some macrophages and T cells were still present, and at 24 days, the xenografts were destroyed. In LEF+CsA-treated animals that were given sera containing an excessive amount of rat anti-porcine xenoreactive antibodies, marked deposits of IgG, and to some extent C3 as well, were detected along the border between intact ICC, and the xenografts were surrounded by macrophages. However, almost no cells infiltrated the grafts, and there were many intact ICC. In animals treated with LEF+CsA+MMF, only occasional infiltrating cells were seen at 12 and 24 days after transplantation, and the endocrine tissue was completely intact.Conclusions.LEF+CsA+MMF prevented rejection of porcine ICC xenografts in the rat for up to 24 days after transplantation.

ISSN:0041-1337    

出版商:OVID    

年代:1997

数据来源: OVID

摘要:

Background.A phase I study of anti-CD4 immunosuppression of cadaver donor renal allograft recipients was conducted by the NIH Cooperative Clinical Trials in Transplantation to assess safety, tolerability, immunoactivity, and pharmacokinetics of multiple infusions of murine anti-human CD4 monoclonal antibody OKT4A.Methods.Thirty patients were enrolled (from August 1992 to October 1993) and received OKT4A at doses of 0.5 mg/kg (24 patients), 1.0 mg/kg (three patients), and 2.0 mg/kg (three patients) beginning and continuing for 12 consecutive days with a standard regimen of cyclosporine, azathioprine, and prednisone. OKT4A treatment was continued postoperatively if serum creatinine 24 hr after transplantation was <85% of pretransplantation baseline creatinine.Results.Ninety-three percent of patients treated at 0.5 mg/kg OKT4A and all patients at higher doses had mean peak CD4 saturations in excess of 90%. A human antimouse antibody response of more than three times pretreatment levels was observed in 84% of patients. There was no evidence of CD4 T-cell depletion. OKT4A was well tolerated without first-dose side effects. For the 19 eligible patients treated with 0.5 mg/kg OKT4A with initial graft function, the 3-month treated rejection rate was 37%. The 2-year graft survival rate for all 30 patients enrolled was 83%, and for the 19 eligible patients it was 95%.Conclusions.The high percentage of CD4 saturation, minimal side effects, the observation of a low 3-month rejection rate, and an excellent 2-year graft survival rate in patients treated with 0.5 mg/kg OKT4A support the continued investigation of an anti-CD4 approach to immunosuppressive therapy.

ISSN:0041-1337    

出版商:OVID    

年代:1997

数据来源: OVID

摘要:

Background.In patients with autoimmune diseases such as vasculitis or systemic lupus erythematosus (SLE), end-stage renal disease develops in a high percentage of patients, and kidney transplantation has become a therapeutic option. However, only limited data about the prognosis and outcome after kidney transplantation are available.Methods.Long-term graft survival and graft function of renal transplant recipients with SLE, Wegener's granulomatosis, microscopic polyangiitis, Goodpasture's syndrome, and Henoch-Schönlein purpura were evaluated in a single center. In addition, the incidence of renal and extrarenal relapses and the impact of the immunosuppressive therapy on the course of the autoimmune disease were studied.Results.Renal transplant recipients with autoimmune diseases such as vasculitis and SLE had a patient survival rate (94% after 5 years) and a graft survival rate (65% after 5 years) comparable to those of patients with other causes of end-stage renal disease (patient survival 88% and graft survival 71% after 5 years). Graft losses due to the underlying disease were rare. Extrarenal relapses occurred in three patients with Wegener's granulomatosis, one patient with microscopic polyangiitis, and three patients with SLE, but were less frequent compared with the period with chronic dialysis therapy. Autoantibody levels in patients with SLE, Wegener's granulomatosis, or microscopic polyangiitis did not seem to influence the outcome.Conclusions.Renal transplantation should be offered to patients with autoimmune diseases. Follow-up should include the short-term control of renal and extrarenal disease activity.

ISSN:0041-1337    

出版商:OVID    

年代:1997

数据来源: OVID