Cyclosporine as a milestone in immunosuppression

In this short review I show how cyclosporine fits into the broader picture of immunosuppression for organ allografting. Before cyclosporine there were some good results, particularly in kidney grafting, but also a failure rate of 50% of grafts by 1 year. Cyclosporine changed the graft survival of 1 year to 80%, although at 10 years the graft survival was little different from patients treated with azathioprine and steroids. Nevertheless, many patients achieved good function in their kidneys when treated with cyclosporine; these patients would have lost the kidneys under the old regimen. The cause of the late failure in patients treated with cyclosporine was predominantly nephrotoxicity due to the calcineurine inhibition, damaging the kidneys. Now that this is better understood and new drugs are available, many regimens have been tried but cyclosporine remains an important tool for the clinician in the treatment of patients with organ allografts.

Adult small intestinal transplantation in England and Wales

BACKGROUND

In 1996 two transplantation centres in the UK were commissioned by the National Specialist Commissioning Advisory Group for England and Wales to assess small intestinal transplantation in adults. The joint experience of the two centres is presented.

METHODS

Patients with irreversible small intestinal failure and complications of parenteral nutrition, and those with abdominal disease requiring extensive visceral resection, were assessed as candidates and where appropriate listed for surgery.

RESULTS

Thirty-six patients were assessed for small intestinal transplantation and, of these, 14 underwent surgery. Twelve patients survived the transplantation procedure. Of these, seven patients were alive at 1 year, five at 3 years and three at 5 years. Three patients remain alive. Patient and graft survival improved with experience; the 1-year survival rate improved in the last 4 years of this experience from 43 to 57 per cent, and the 3-year survival rate from 29 to 43 per cent.

CONCLUSION

Small intestinal transplantation is associated with a high mortality rate but may benefit carefully selected patients in whom conservative management is likely to carry a greater mortality rate.

Relapsing encephalopathy following small bowel transplantation

We report a case of a 40-year-old man presenting with relapsing encephalopathy 4 years post-intestinal transplantation. Each episode was preceded by symptoms suggestive of subacute intestinal obstruction, marked dehydration, and, on one occasion, grade 4 encephalopathy. Physical examination revealed hypertonia, clonus, and hyperreflexia. Biochemistry was consistent with renal impairment, metabolic alkalosis, hyperammonaemia, and normal liver function. Plain radiographs and abdominal computed tomography revealed dilated proximal small bowel loops, and barium radiography demonstrated a strictured distal anastomosis. Hydrogen breath testing indicated bacterial overgrowth. Following rehydration and antibiotic therapy, the patient recovered fully between episodes. Further episodes of encephalopathy did not recur following resection of the distal anastomotic stricture and resolution of bacterial overgrowth. Unfortunately, one year later the patient died of pneumonia. To the best of our knowledge, encephalopathy secondary to intestinal transplant related porto-caval shunt and bacterial overgrowth in strictured bowel has not been previously reported but might have implications for the management of future patients.

Bicêtre hospital experience with sirolimus-based therapy in human renal transplantation: the Sirolimus European Renal Transplant Study

In 11 European centers, first cadaveric renal allograft recipients were randomized to CsA (n = 42) or sirolimus (n = 41). Dosing of these agents was concentration-controlled and open-labeled. All patients received corticosteroids and azathioprine. At 12 months, graft survival (98% sirolimus vs 93% CsA), patient survival (100% vs 98%), and incidence of biopsy-confirmed acute rejection (41% vs 38%) were similar. Serum creatinine was lower with sirolimus, significantly (P </=.05) so at 3 and 4 months, and serum uric acid and magnesium were normal. Laboratory abnormalities were reported significantly more often with sirolimus, which included hypertriglyceridemia (51% vs 12%), hypercholesterolemia (44% vs 14%), thrombocytopenia (37% vs 0%), leukopenia (39% vs 14%), and, of lesser importance, increased liver enzymes and hypokalemia. These abnormalities improved 2 months after transplantation when the sirolimus target trough level was lowered from 30 to 15 ng/mL. Occurrence of cytomegalovirus was comparable (14% vs 12%), but incidence of herpes simplex (24% vs 10%, P =.08) and pneumonia (17% vs 2%, P =.03) were higher with sirolimus. No gingival hyperplasia was seen with sirolimus, tremor was rare, and hypertension was less frequent (17% vs 33%). Two malignancies were observed with CsA, none with sirolimus. Results at 12 months suggest that sirolimus can be used as base therapy in the prophylaxis of acute renal transplant rejection, and has a safety profile that differs from that of CsA.

The future of organ transplantation: from the laboratory to the clinic

This is a short review of tolerance from the point of view of the clinician. Various examples of tolerance occurring in patients and animal models that relate to the clinical experience are described. It is suggested that there may be different mechanisms by which tolerance is achieved, but from the patient's point of view operational tolerance is the goal, whereby, after a short induction procedure, the patient will maintain good function in the grafted organ indefinitely without maintenance immunosuppression. It is pointed out that such a goal may be difficult to achieve with any given protocol due to the enormous variation between donors and recipients of organ grafts of tissue matching, innate immune reactivity and susceptibility to disturbance of a tolerant state by infections or allergic reactions. Thus the case is made for prope or almost tolerance in which graft acceptance is maintained by a low, non-toxic dosage of maintenance immunosuppression that may not be required indefinitely.

Combined transplantation of the heart, lung, and liver

Combined transplantation of the heart, lung, and liver may be indicated in patients with either end-stage respiratory failure complicated by advanced liver disease or end-stage liver failure complicated by advanced lung disease. A retrospective review of nine patients who underwent combined heart-lung-liver transplantation in Cambridge (1986-99) was carried out. The 1-year and 5-year actuarial survival was 56% and 42%, respectively. Combined heart-lung-liver transplantation is a feasible option for a few patients and has a 5-year survival similar to heart-lung transplantation but with a lower incidence of acute and chronic rejection.

Solitary splenic metastasis: case report and review of the literature

Solitary splenic lesion is a rare presentation of a previous or current malignancy. We describe a case of an isolated splenic lesion caused by endometrial carcinoma and summarize all the published reports on solitary splenic metastasis.

Distribution and persistence of antigen-presenting cells after intrathymic injection

Intrathymic injection of donor immune cells has been shown by previous studies to prolong survival of rat allogeneic tissues. The aim of this pilot study was to assess the distribution and the persistence of intrathymically (i.t.) injected purified antigen presenting cells (APC) over a period of time in the rat model DA-to-WAG (RT1av to RT1u) using a specific monoclonal antibody (Mab) with RT1Aa class I polymorphic specificity (R3/13 clone). Purified non-parenchymal cells (NPC) or dendritic cells (DC) were prepared from liver and spleen of DA rats with a purity of greater than 60% and 90%, respectively, shown by selected Mab staining methods. DA NPC (1 x 10(6)) or DC (5 x 10(5)) in 20 microl were injected into both lobes of the thymus of WAG rats with or without 1 ml antilymphocyte serum (ALS) intraperitoneally. Thymus tissue was removed on days 3, 5, 10, 20 and 30, and processed for frozen sections and immunohistochemical staining with R3/13. Numerous DA-positive cells were detected in the first 3-10 days post-i.t. inoculation in both NPC- and DC-treated rats, with or without ALS. After day 10, the proportion of positive cells decreased in all cases except in rats given NPC and ALS, where similar numbers of R3/13-positive cells were seen throughout. These DA-positive cells were mostly found in the medullary portion of the thymus at the corticomedullary junction in close proximity to thymic dendritic interdigitating cells. We concluded from this pilot study that the injected cells remained in the thymus for a limited period. However, the immunosuppressive effect of ALS promoted some degree of persistence of donor APC in the thymus beyond 30 days. Further studies are in progress to reveal the specificity of these cells.

Corticosteroids and concomitant medication in the European multicentre study of FK 506 and cyclosporin in primary liver transplantation

The steroid-sparing effect and the use of concomitant medication during the treatment of liver transplant patients with the novel immunosuppressant FK 506 were evaluated within the European multicentre, randomized, parallel-group study in liver transplantation. Patients undergoing primary liver transplantation were randomized to treatment with FK 506 (n = 267) or with a cyclosporin-based immunosuppressive regimen (n = 273). The total cumulative steroid usage was significantly reduced in the FK 506 treatment group, which is likely to have resulted from the lower incidence of acute rejection in these patients. The number of patients receiving antidiabetic, diuretic and antihypertensive therapy did not differ between the two treatment groups, even though the incidence of diabetes mellitus and oliguria was significantly higher in the FK 506 group. It can, therefore, be assumed that in a number of such cases the severity of these events was very mild necessitating no specific therapy.

The use of ABO-compatible mismatched livers in the UK

Elective blood group O liver recipients appear to wait longer than most other groups for matched donors. The aim of this study was to confirm the suspected differences in elective waiting times in the UK using data from the United Kingdom Transplant Support Service, and to determine some of the factors responsible for them. The findings were that potential group O recipients waited significantly longer than other groups for transplantation, and that 22% of group O livers were going to non-O recipients. AB, the group with the shortest waiting time, was receiving 74.5% mismatched (but compatible) grafts, from all other groups.

Glucose metabolism in liver transplant recipients treated with FK 506 or cyclosporin in the European multicentre study

From September 1990 to January 1992, 545 liver transplant patients were randomised to treatment with either FK506 and prednisolone or a conventional cyclosporin-based immunosuppressive regimen (CBIR). Eight European centres participated in the study. Adverse events were reported as defined by each centre. Hyperglycaemia was reported as an adverse event in 30.7% of patients receiving FK 506 compared with 20.5% in the CBIR group (P < 0.01). Diabetes mellitus was reported in 17.2% of patients treated with FK 506 and 9.5% of CBIR-treated patients (P < 0.05). Treatment with insulin was required in 12.0% of patients in the DK 506 treatment group and in 5% in the CBIR group at 6 months. Initially, higher doses of FK 506 were used. During the study, the protocol was changed to allow a lower dose of FK 506. When the early and late cohorts of patients were compared, the incidence of diabetes mellitus fell from 23.9% to 10.5% in FK 506-treated patients but remained relatively constant in the CBIR group (10.4% to 8.7%). The median cumulative doses of i.v. and p.o. corticosteroids were significantly greater in the CBIR group. Thus, in the overall series, the incidence of diabetes mellitus was significantly greater in the FK 506 group as compared with the CBIR group. However, when a lower FK 506 dose was used during the second half of the study, the difference in the incidence of diabetes mellitus disappeared.

Renal complications and development of hypertension in the European study of FK 506 and cyclosporin in primary liver transplant recipients

We examined the occurrence of renal complications and hypertension in 540 primary liver recipients entered into the European liver trial comparing primary FK 506 to a cyclosporin A based immunosuppression regimen (CBIR). No difference in serious renal impairment or mean creatinine levels was observed with similar rates of "kidney failure" (FK 506 9.4% vs. CBIR 7.3%) and dialysis requirements (FK 506 12% vs. CBIR 11%). "Abnormal kidney function", a less serious parameter of renal impairment, was reported in 89 recipients (33%) in the FK 506 group versus 58 (21%) in the CBIR group (P < 0.01). Development of this complication was associated with elevated intravenous FK 506 dosing schedules, with the mean cumulative dose 43% higher than treated patients with unaffected kidney function. In a later cohort of patients where intravenous dosing was lower, no significant difference in renal complications was detectable. The 6-month prevalence rate of systemic arterial hypertension was noted to be lower in the FK 506-treated patients compared to the CBIR group [33 (17.2%) vs. 47 (25.7%)].

Does intrathymic injection of alloantigen-presenting cells before islet allo-transplantation prolong graft survival?

Current immunosuppressive agents have potentially dangerous side-effects, are non-specific and most are also diabetogenic. We investigated tolerance induction with intrathymic injection of purified antigen-presenting cells (APC) plus a single dose of antilymphocyte serum (ALS) intraperitoneally before allogeneic islet transplantation in the rat model WAG to Lewis (RT1u to RT1l). Purified donor APC [non-parenchymal cells (NPC) or dendritic cells (DC)] were prepared from liver and spleen, respectively. Isograft function for more than 120 days proved that islet isolation, purification and transplantation procedures were adequate. A total of WAG DC (4 x 10(5)) or NPC (2 x 10(6)) in 20 microl were injected into both lobes of the thymus of 140-210 g Lewis recipients followed by a single injection of ALS. Three days later, diabetes was induced with streptozotocin (60 mg/kg). Four days later allogeneic islets were grafted into the liver by intraportal injection of 3000 WAG islets. Control animals (n = 8) received 20 microl saline intrathymically instead of APC. Graft function was assessed by blood glucose measurements with glucose levels above 15 mmol/l on 3 consecutive days defined as graft rejection. Animals given DC (n = 9) or NPC (n = 8) intrathymically plus 1 ml of ALS, rejected their grafts in an accelerated fashion with a median survival time (MST) of 3 days. However, control animals rejected their grafts with a MST of 7 days, but with two animals surviving for more than 2 months. In conclusion, intrathymic inoculation with purified APC plus a single dose of ALS did not prolong allogeneic islet graft function but induced accelerated rejection of the islet allografts.

Optimal FK 506 dosage in patients under primary immunosuppression following liver transplantation

In a retrospective study, we analysed the FK 506 dosage used in primary liver graft recipients enrolled in the European FK 506 multicenter trial conducted from September 1990 to January 1992. In addition, a second cohort of patients treated more recently in a single centre was investigated. The impact of different dosing strategies on the clinical course of the patients was analysed with special emphasis on the incidence of rejection episodes and FK 506 side-effects. Among the patients enrolled in the European FK 506 multicenter trial, those patients enrolled during the "early" phase of the study received a higher oral FK 506 dose [mean oral dosage on day 7 = 0.19 mg/kg body weight (bw) per day, n = 134] compared to patients enrolled during the "late" period of the study (mean oral dosage on day 7 = 0.14 mg/kg bw per day, n = 133). This lower dosage was the result of several protocol amendments performed to reduce the incidence of FK 506 side-effects. Lowering of the FK 506 dosage was accompanied by a reduction in the long-term prevalence of side-effects such as diabetes (n. s.) or hypertension (P < 0.05), while patient survival and rejection frequency remained constant. Patients treated in centres with online FK 506 blood level monitoring experienced significantly less hypertension, less episodes of diabetes and less rejection episodes compared to patients treated in centres without. The clinical course of those patients enrolled in the multicentre trial was compared with the course of a cohort of liver-grafted patients treated with FK 506 more recently in a single centre. These patients had a further reduction in the FK 506 dosage (0.10 mg/kg bw per day p.o. or less according to whole blood levels, with no intravenous FK 506 administration). When compared to patients enrolled in the multicentre trial, these patients experienced less side-effects (nephrotoxicity, hypertension, serious early neurotoxicity) while adaequate immunosuppression was maintained.

FK 506 primary immunosuppression following emergency liver transplantation for fulminant hepatic failure. European FK 506 Study Liver Group

The efficacy and safety of an FK 506-compared to a cyclosporin A based immunosuppression regimen was examined in liver recipients who underwent transplantation for fulminant hepatic failure in the European FK 506 liver study. A consistent trend towards improved patient and graft survival noted in the FK 506-treated patients was apparent from the first postoperative week (e. g. patient survival: day 7, 95.5% vs. 82.1% and month 6, 72.7% vs. 60.7%). Acute (in particular intractable) rejection was less frequent in the FK 506 group (e. g. cumulative intractable rejection rate at 6 months, 6.2% vs. 22.6%). In a single centre (Kings College Hospital), 17 patients were studied in more detail. The FK 506 treatment group had improved graft function, lower steroid requirements and episodes of infection. Accompanying these benefits, apache 111 and TISS scores were lower in this group in the early posttransplant period. Intensive care discharge was earlier and both treatment groups experienced similar toxicity.

Focus on intractable rejection: 6-month results of the European multicentre liver study of FK 506 and cyclosporin A

The incidence of intractable rejection was evaluated during the course of a multicentre, randomised, parallel-group study comparing the efficacy and safety of FK 506 and conventional cyclosporin A-based immunosuppressive regimens in patients undergoing primary liver transplantation. A diagnosis of intractable rejection was made if there was histological evidence of unchanged or worsening acute rejection, or chronic rejection after two discrete courses of antirejection therapy. Antirejection regimens were specific to each centre. Patients who experienced intractable rejection could be withdrawn from the study. Patients who were withdrawn from the cyclosporin A treatment group could subsequently receive FK 506 therapy and vice-versa. Intractable rejection was diagnosed in 32/540 patients (5.9%): 7/267 patients (2.6%) in the FK 506 treatment group and 25/273 patients (9.2%) receiving cyclosporin A therapy (P < 0.01). Of these 32 patients, 25 were withdrawn from the study: 3 and 22, from the FK 506 and cyclosporin A treatment groups, respectively. All three patients withdrawn from the FK 506 treatment group are alive: two having undergone retransplantation. Of the 22 patients withdrawn from the cyclosporin A group and converted to FK 506 therapy, 6 were retransplanted, 4 of whom subsequently died. A further two patients died without retransplantation. Thus, in 14 of the 16 patients who were still alive at 6 months, the liver graft was saved after conversion to FK 506 treatment. The reduced incidence of intractable rejection in patients receiving treatment with FK 506, together with the successful rescue of patients developing intractable rejection while receiving cyclosporin A, suggests that FK 506 is an effective immunosuppressive agent following orthotopic liver transplantation.

CD4 and CD8 monoclonal antibody therapy in canine renal allografts

Therapy with CD4 and CD8 monoclonal antibodies was evaluated in dogs which received double-haplotype MHC-mismatched renal allografts. Neither CD4 nor CD8 monoclonal antibodies given alone prolonged allografts survival (creatinine > or = 300 micromol/l) beyond 7 days. However, combined therapy with CD4 and CD8 antibodies given up to day 10 did prolong allograft survival to a median of 14 days. A longer (21 day) course of CD4 and CD8 antibodies did not extend allograft survival further. The effect of prolonged antibody therapy was restricted by the occurrence of both an antiglobulin response and an anaphylactoid reaction to the monoclonal antibody preparation. When the CD4 and CD8 antibodies were combined with a pan-T-cell-depleting Thy-1 antibody, the survival of double-haplotype mismatched allografts was further prolonged (median 16 days). The median survival of single-haplotype mismatched renal allografts on this triple therapy was 21 days, with one surviving to day 36.

Neurological complications in the European multicentre study of FK 506 and cyclosporin in primary liver transplantation

Neurological complications were examined in a multicentre, randomized, parallel-group study of 545 patients undergoing primary liver transplantation to compare the efficacy and safety of FK 506- and cyclosporin A-based immunosuppressive regimens (CBIR). In an additional analysis, patients were divided into early and late randomized cohorts to detect the influence of protocol amendements that allowed for FK 506 dose reductions. Initial follow-up was for 6 months. Tremor, headache and insomnia were the most frequently reported adverse events involving the neurological system. Whereas these neurological symptoms were observed significantly more often in FK 506-treated patients (P < 0.05 vs. CsA for the overall population), this was no longer the case for the late FK 506 and CBIR cohorts. The risk of FK 506-treated patients developing tremor was related to the initial i.v. dose, the rate of administration of the i.v. dose and the daily dose (P < 0.01). Headache was significantly correlated with the FK 506 dose (P < 0.05), and insomnia was not related to any dosing variable. Major neurological symptoms, including psychosis, convulsion, coma, aphasia and intracranial haemorrhage, were reported with a low frequency (0.4-5.2%), and differences between both treatment groups were neither significant for the overall population nor for the early and late cohorts of FK 506 and CBIR. Data from the late cohorts showed no differences in the overall incidence of neurological adverse events between FK 506- and CBIR-treated patients.

Life-supporting human complement regulator decay accelerating factor transgenic pig liver xenograft maintains the metabolic function and coagulation in the nonhuman primate for up to 8 days

BACKGROUND

It is not known whether the pig liver is capable of functioning efficiently when transplanted into a primate, neither is there experience in transplanting a liver from a transgenic pigs expressing the human complement regulator human complement regulator decay accelerating factor (h-DAF) into a baboon. The objective of this study was to determine whether the porcine liver would support the metabolic functions of non-human primates and to establish the effect of hDAF expression in the prevention of hyperacute rejection of porcine livers transplanted into primates.

METHODS

Five orthotopic liver xenotransplants from pig to baboon were carried out: three from unmodified pigs and two using livers from h-DAF transgenic pigs.

FINDINGS

The three control animals transplanted with livers from unmodified pigs survived for less than 12 hr. Baboons transplanted with livers from h-DAF transgenic pigs survived for 4 and 8 days. Hyperacute rejection was not detected in the baboons transplanted with hDAF transgenic pig livers; however, it was demonstrated in the three transplants from unmodified pigs. Baboons transplanted with livers from h-DAF transgenic pigs were extubated at postoperative day 1 and were awake and able to eat and drink. In the recipients of hDAF transgenic pig livers the clotting parameters reached nearly normal levels at day 2 after transplantation and remained normal up to the end of the experiments. In these hDAF liver recipients, porcine fibrinogen was first detected in the baboon plasma 2 hr postreperfusion, and was present up to the end of the experiments. One animal was euthanized at day 8 after development of sepsis and coagulopathy, the other animal arrested at day 4, after an episode of vomiting and aspiration. The postmortem examination of the hDAF transgenic liver xenografts did not demonstrate rejection.

INTERPRETATION

The livers from h-DAF transgenic pigs did not undergo hyperacute rejection after orthotopic xenotransplantation in baboons. When HAR is abrogated, the porcine liver maintains sufficient coagulation and protein levels in the baboon up to 8 days after OLT.

Historic landmarks in clinical transplantation: conclusions from the consensus conference at the University of California, Los Angeles

The transplantation of organs, cells, and tissues has burgeoned during the last quarter century, with the development of multiple new specialty fields. However, the basic principles that made this possible were established over a three-decade period, beginning during World War II and ending in 1974. At the historical consensus conference held at UCLA in March 1999, 11 early workers in the basic science or clinical practice of transplantation (or both) reached agreement on the most significant contributions of this era that ultimately made transplantation the robust clinical discipline it is today. These discoveries and achievements are summarized here in six tables and annotated with references.