ISSN:0041-1337    

出版商:OVID    

年代:1995

数据来源: OVID

摘要:

Fas/Fas ligand interactions serve as a signaling pathway for apoptosis (1–3), an important regulatory mechanism in the development and function of the immune system (4–9). Recent evidence that Fas-dependent apoptosis is also an important mode of T cell cytotoxicity (10–13) suggested that Fas might play a critical role in the effector phase of T-dependent immune responses, such as allograft rejection. We observed that Fas transcripts are constitutively expressed in syngeneic and allogeneic murine cardiac transplants, while Fas ligand (FasL) is up-regulated only in rejecting allografts. Surprisingly, the absence of an intact Fas/FasL pathway did not alter the tempo of allograft rejection, even CD4-dependent rejection. These results indicate that Fas/FasL interactions are not essential mediators of T cell-induced allograft damage. Rather, as suggested in other studies, the Fas pathway may be principally involved in the regulation of clonal expansion and subsequent contraction of T cell populations during immune responses.

ISSN:0041-1337    

出版商:OVID    

年代:1995

数据来源: OVID

摘要:

Mycophenolate mofetil (MMF), a new immunosup-pressant that selectively inhibits proliferation of T and B lymphocytes, may reduce the frequency and severity of acute graft rejection. Acute graft rejection is the leading cause of graft loss in cadaveric renal transplantation. The purpose of this randomized, double-blind, multicenter study was to evaluate the efficacy and safety of MMF for the prevention of acute rejection episodes in adult patients during the first 6 months after renal transplantation. A total of 499 patients who were to receive a primary cadaveric renal allograft as their first transplant were randomized to receive MMF 1.0 g b.i.d. (MMF 2 g treatment group), MMF 1.5 g b.i.d. (MMF 3 g treatment group), or azathioprine 1–2 mg/kg/day. CsA, corticosteroids, and antithymocyte globulin (ATGAM) were administered as part of a quadruple sequential induction protocol. The primary efficacy endpoint was biopsy-proven rejection or treatment failure (defined as graft loss, death, or premature withdrawal from the study for any reason) during the first 6 months after transplant. All enrolled patients were included in the primary analyses of efficacy on the basis of intent to treat. The 495 patients who received study drug were included in the safety and secondary efficacy analyses. Biopsy-proven acute rejection episodes or treatment failure occurred in 47.6% of patients in the azathioprine group compared with 31.1% (P=0.0015) and 31.3% (P=0.0021) of patients in the MMF 2 g and 3 g treatment groups, respectively. Time to first biopsy-proven rejection episode or treatment failure was significantly longer for MMF 2 g versus azathioprine (P=0.0036) and MMF 3 g versus azathioprine (P=0.0006). First biopsy-proven rejection alone occurred in 38.0% of patients who received azathioprine compared with 19.8% and 17.5% of patients who received MMF 2 g and 3 g, respectively. Patients in the azathioprine group received a greater number of full courses of antirejection treatment as compared with the MMF 2 g and MMF 3 g groups (44.5%, 24.8%, and 21.1%, respectively). The use of antilymphocyte agents to treat rejection was greater in the azathioprine group (20.1%) compared with the MMF 2 g group (10.3%) and the MMF 3 g group (5.4%). At 6 months after transplant, graft and patient survival were similar in all 3 treatment groups. The incidence and types of adverse events were similar among treatment groups, with the exception of a higher incidence of diarrhea, certain other infrequent gastrointestinal adverse events, clinically important leukopenia, and tissue-invasive CMV disease in the MMF groups, particularly in the MMF 3 g group. Three patients who received MMF developed lymphoma/lymphoproliferative disorder. This study demonstrated that MMF administered at a dosage of 2 g or 3 g daily, in combination with maintenance CsA and corticosteroids as triple therapy following ATGAM induction therapy, is more effective than an otherwise identical regimen that includes azathioprine instead of MMF in preventing acute allograft rejection in first cadaveric renal transplant patients. This regimen also has an acceptable adverse event profile. The MMF 3 g dosage was considered to be somewhat less well tolerated than the MMF 2 g dosage.

ISSN:0041-1337    

出版商:OVID    

年代:1995

数据来源: OVID

摘要:

Liver transplants in rodents or pigs are often spontaneously accepted across a complete MHC mismatch. They induce tolerance to grafts of other organs or skin of liver donor strain and can even suppress ongoing rejection of heart grafts. It has not been established whether liver-induced tolerance is due to components of the liver or to passenger leukocytes within the liver. We depleted populations of passenger leukocytes from the transplanted liver by irradiation of the donor with 10 Gy, followed after 7 days by transplantation of the liver. Recipients of livers from irradiated donors had a median survival of 16 days compared with > 100 days for recipients of livers from normal donors. Examination of recipients of irradiated donor livers showed that allograft rejection was the cause of death. Syngeneic transplants of irradiated PVG donor to PVG recipient or of irradiated DA donor to DA recipient survived indefinitely. Parking of livers from irradiated PVG donors in normal PVG animals for 36 hr reconstituted tolerance when the livers were retransplanted to DA recipients. Livers from irradiated donors had greatly reduced passenger leukocyte numbers compared with normal or parked livers, with virtually complete loss of lymphocytes. These results show that spontaneous liver allograft acceptance is associated with populations of passenger leukocytes that are depleted by donor irradiation.

ISSN:0041-1337    

出版商:OVID    

年代:1995

数据来源: OVID

摘要:

CsA induces a reversible inhibition of proliferation in cultured murine proximal tubular cells (MCT cells) and syngeneic tubulointerstitial fibroblasts (TFB). To test whether this effect may be caused by endogenous synthesis and release of transforming growth factor-β1(TGF-β1), a well-known inhibitor of mitosis, MCT cells and TFB grown in serum-free media were treated with different concentrations of CsA. CsA, in a dose-dependent manner in a range of 500–2000 ng/ml, stimulated expression of TGF-β1protein and steady-state mRNA levels in both cell lines (MCT cells: controls, 9.3±1.0; 1500 ng/ml CsA, 19.1±6.1 pg TGF-β1/103cells [P<0.05 vs. controls]; TFB: controls, 5.4±0.9; 1500 ng/ml CsA, 7.7±0.3 pg TGF-β1/103cells; n=6). Short-term daily intraperitoneal injections of CsA (40 mg/kg body weight/day) into SJL mice for 1 and 4 weeks also induced an increase in whole kidney levels of TGF-β1mRNA. Incubation of MCT cells and TFB with CsA in the presence of 30 μg/ml of a neutralizing anti-TGF-β1–3mAb partly reversed the cell cycle arrest induced by CsA. These data suggest that CsA-mediated intra-renal synthesis and release of TGF-β1may play a role in the CsA-induced growth arrest and might therefore be relevant in the development of chronic CsA neph-rotoxicity, which is characterized by striped fibrosis and tubular atrophy.

ISSN:0041-1337    

出版商:OVID    

年代:1995

数据来源: OVID

摘要:

Patients with preformed antibodies against HLA molecules accumulate on renal transplant waiting lists and have inferior graft survival compared with nonsensitized patients. One hundred patients were included in a program of pretransplant removal of antibodies by plasma exchange (n=90) or immunoadsorption (n=10) in addition to prednisolone and cyclophosphamide medication. After plasma exchange, the panel reactivity and the antibody titer were reduced in about half of the patients, and after immunoadsorption the panel reactivity fell in 6 of 10 patients. Of the 83 patients who received grafts, 17 received a graft from a living donor (LD) and 66 received a graft from a cadaver donor (CD). Patients with a positive crossmatch against their LD were included in the program and were thus grafted with a recent positive, current negative crossmatched organ. Fifteen CD graft recipients had a pretreatment positive crossmatch toward their donor. No episodes of hyperacute rejection were seen. One- and 4-year graft survival rates in LD transplants with a recent positive and current negative crossmatch were 77% and 64%, respectively. At 1 and 4 years, graft survival rates were 70% and 57% in pretreated first CD graft recipients (n=27) and 61% and 47% in pretreated regrafted patients (n=39), respectively. In this program, a high rate of transplantation among the sensitized patients was achieved. Graft survival was inferior to that seen in nonsensitized patients, but was comparable to graft survival in sensitized patients at other centers.

ISSN:0041-1337    

出版商:OVID    

年代:1995

数据来源: OVID

摘要:

In a double-blind, randomized, placebo-controlled trial, BT563, a murine IgGt anti-IL-2R antibody, was given as a rejection prophylaxis after kidney transplantation. Drug-related side effects were not observed. During the 10-day course of BT563, no rejections (0/27) were found, whereas a rejection episode occurred in 7 patients (7/29) (P=0.01) during placebo treatment. Within the first 4 postoperative weeks, freedom from rejection in the BT563 group and in the placebo group was 96% vs. 76% (P=0.05). Due to rejection in the placebo group, 2 grafts were lost. At 3 months, an overall rejection incidence in the BT563 and placebo group was found of 3/27 (11%) vs. 8/29 (28%) patients (P=0.18). Infectious complications were distributed equally between the 2 groups. CMV disease, found in 3 placebo-treated patients, occurred after rejection treatment (2/3). Within the BT563 group, 1 patient lost his graft due to renal artery thrombosis, 2 grafts were lost as a result of technical failure, and 2 patients had a squamous cell carcinoma that could be treated curatively. We conclude that the use of the anti-IL-2R mAb BT563 effectively prevents rejection after kidney transplantation without increasing infectious complications.

ISSN:0041-1337    

出版商:OVID    

年代:1995

数据来源: OVID

摘要:

Previous studies from our center have shown that donor-recipient HLA-DR mismatches (MM), characterized by the presence of the DR antigen in the donor but not in the recipient or vice versa, are associated with differential effects on graft survival (GS): some of them are beneficial (BEN) with results similar to those of HLA-DR identical or compatible pairs (85% 18 months GS) and some are detrimental (DET) (64% 18 months GS), whereas the other MM, neither BEN nor DET (neutral [NEU]) yield intermediate results (78% 18 months GS). The aim of the present study was to update the results at a longer follow-up time and to assess whether they are influenced or not by prophylactic administration of anti-CD3 mAb (OKT3). The analysis of 234 transplantations performed from 1980 to 1994 with only 1 HLA-DR MM confirmed the BEN effects of HLA-DR5 in either the donor or the recipient and the DET effects of HLA-DR1 or -DR2 in the donor and of HLA-DR2 or -DRW6 in the recipient. These effects were independent of those exerted by other, HLA-DR not related, prognostic factors. The transplants with 1 HLA-DR MM were then compared with those with zero HLA-DR MM (n=378) and 4 groups were formed according to 2 levels of HLA-DR MM (zero or BEN MM vs. NEU or DET MM) and immunosuppression (with vs. without OKT3 prophylaxis). GS at 5 years was 63% in the group with either zero or BEN MM as compared with 41% in the group with either NEU or DET MM in the absence of OKT3 prophylaxis (P<0,02); in comparison, with OKT3 prophylaxis, GS at 5 years was 73% in the group with either zero or BEN MM as compared with 58% in the group with either NEU or DET MM (P=0.07). We conclude that the differential effects of HLA-DR MM on GS are still observed under OKT3 prophylaxis, that the effects of HLA-DR and immunosuppression on graft outcome are additive, and that OKT3 induction therapy is superior to therapy without OKT3. These observations could have important implications for the allocation policy and management of renal transplants.

ISSN:0041-1337    

出版商:OVID    

年代:1995

数据来源: OVID

摘要:

We analyzed the relation between FK506 trough levels (ELISA: patients 1–41, EVfx: patients 42–70) and rejection and/or viral infection episodes, retrospectively, in the first 70 consecutive cases of living related liver transplantation. Twenty patients (28.6%) had rejection episodes. Of the 13 patients who had evidence of rejection during the first 3 months, 6 patients without infection and 7 patients with viral infection showed low concentrations of FK506 (<5 ng/ml). Twelve patients were treated and improved with high dose steroid administration and an increase in the FK506 dosage. One patient died of refractory rejection. Nine patients had evidence of rejection after the first 3 months. In 3 patients, weaning from FK506 intiated the rejection episodes. Five patients repeated rejection and 4 patients required a third immunosuppressant (azathioprine). Viral infection included CMV (11 cases), EBV (13 cases), HZV (3 cases), and HSV (1 case). Excess immunosuppression might have been the cause, but no clear correlation was found.We propose that the optimal dosage of FK506 obtained by monitoring the trough levels using the IMx method should maintain a 10–20 ng/ml level during the first month, and a 5–10 ng/ml level at the second and third months.

ISSN:0041-1337    

出版商:OVID    

年代:1995

数据来源: OVID

摘要:

Rapamycin, a potent immunosuppressive drug that prevents rejection of organ transplants in many animals, caused profound growth inhibition in an immature B cell lymphoma, BKS-2, at very low concentrations (2 ng/ml). Similar growth inhibition was also observed in a series of B cell lymphomas (i.e., L1.2, NFS.1.1, and WEHI-279) as well as in thymoma cells. The cell death induced by rapamycin in BKS-2 lymphoma was found to be via programmed cell death, or apoptosis. In contrast to rapamycin, neither FK506 nor CsA affected the normal growth of these cells. FK506, but not CsA antagonized the effect of rapamycin and rescued the BKS-2 cells from undergoing apoptosis. Further, suboptimal concentrations of antiIgM antibodies and rapamycin acted synergistically in causing the growth inhibition of BKS-2 cells and this inhibitory effect was also completely reversed by FK506. Thus, rapamycin appeared to inhibit lymphoma growth by binding to FK506 binding protein. These results indicate that rapamycin should be evaluated as an effective immunosuppressive therapeutic agent to prevent the incidence of lymphoma after transplantations.

ISSN:0041-1337    

出版商:OVID    

年代:1995

数据来源: OVID