Obtaining regulatory T cells from uraemic patients awaiting kidney transplantation for use in clinical trials.

Adoptive transfer of regulatory T cells (T(regs)) has been proposed for use as a cellular therapy to induce transplantation tolerance. Preclinical data are encouraging, and clinical trials with T(reg) therapy are anticipated. In this study, we investigate different strategies for the isolation and expansion of CD4(+) CD25(high) CD127(low) T(regs) from uraemic patients. We use allogeneic dendritic cells (DCs) as feeder cells for the expansion and compare T(reg) preparations isolated by either fluorescence activated cell sorting (FACS) or magnetic activated cell sorting (MACS) that have been expanded subsequently with either mature or tolerogenic DCs. Expanded T(reg) preparations have been characterized by their purity, cytokine production and in-vitro suppressive ability. The results show that T(reg) preparations can be isolated from uraemic patients by both FACS and MACS. Also, the type of feeder cells used in the expansion affects both the purity and the functional properties of the T(reg) preparations. In particular, FACS-sorted T(reg) preparations expanded with mature DCs secrete more interleukin (IL)-10 and granzyme B than FACS-sorted T(reg) preparations expanded with tolerogenic DCs. This is a direct comparison between different isolation techniques and expansion protocols with T(regs) from uraemic patients that may guide future efforts to produce clinical-grade T(regs) for use in kidney transplantation.

Initial experience with hypothermic machine perfusion of kidneys from deceased donors in the Uppsala region in Sweden.

BACKGROUND: Simple cold storage (CS) is the gold standard for organ preservation. Recently, evidence has been presented suggesting compared with CS hypothermic machine perfusion (HMP) improves the quality and outcome of kidneys for transplantation. Uppsala has used the LifePort Kidney Transporter to preserve deceased donor kidneys. We evaluated our first single-center 52 cases retrospectively. METHODS: Deceased donor kidneys preserved with HMP between July 2010 and July 2012 (n = 52) were compared with a matched historical cohort of organs preserved by CS between January 2009 and July 2012 (n = 87). We evaluated delayed graft function (DGF), creatinine level at hospital discharge, length of hospital stay, incidence of acute rejection episodes during the first year after transplantation, and graft survival. RESULTS: Both groups included approximately 69% expanded criteria donors (ECD). Median cold ischemia time (CIT) was 12.8 hours in the HMP group and 11.7 hours in the CS group. The incidence of DGF was 11.5% with HMP and 20.7% with CS. Compared with CS, HMP significantly reduced the occurrence of DGF from 21.4% to 0% using standard criteria kidneys (P = .046), whereas the use of HMP did not impact the occurrence of DGF with ECD kidneys. The creatinine level at hospital discharge was lower after HMP than after CS (P = .047). No difference in graft survival was observed between the groups. CONCLUSIONS: Machine perfusion resulted in a lower occurrence of DGF using kidneys from standard criteria donors with a lower creatinine at hospital discharge among the cohort with reasonably low CIT. Using machine perfusion seems to be safe; no adverse surgical events occurred during the study period.

Time trends in risk and risk determinants of non-Hodgkin lymphoma in solid organ transplant recipients.

Organ transplantation increases risk of non-Hodgkin lymphoma (NHL), but long-term risk and time trends have seldom been evaluated. Immunosuppressive drug load is an important risk determinant, but the details are unclear. We studied NHL risk in a nationwide Swedish cohort of 11 081 graft recipients transplanted 1970-2008. Relative risks (RRs) were estimated within the cohort and versus the general population by age, sex, follow-up time and calendar period. NHL risk was also assessed by cumulative and average doses of immunosuppressive treatments in a nested case-control design throughout 1997 using conditional logistic regression. We observed 153 NHL cases during 97 853 years of follow-up. Compared with the general population, NHL risk was eightfold increased (RR 7.9; 95% confidence interval [CI] 6.6-9.4), and increased risks persisted after ≥15 years of follow-up among kidney (6.1; 95% CI 3.5-10) and nonkidney recipients (44; 14-103). Among nonkidney recipients, NHL risk was lower in the 2000s compared with the 1990s (0.5; 95% CI 0.3-1.0; p = 0.04). A high average dose of antithymocyte immunoglobulin (ATG) conferred an eightfold increased risk of NHL (OR 8.5; 95% CI 1.9-38). To conclude, posttransplant NHL risk decreased during the last decade among nonkidney recipients, possibly because of a more careful use of ATG, the introduction of new drugs, or both.

Efficacy and safety of continuous local infusion of ropivacaine after retroperitoneoscopic live donor nephrectomy.

Morphine-based analgesia is effective but can compromise donor safety. We investigated whether continuous infusion of local anesthetics (CILA) can provide sufficient pain control and reduce morbidity related to opiate analgesics after hand-assisted retroperitoneoscopic (HARS) live donor nephrectomy. Forty consecutive live kidney donors underwent HARS and were treated with the ON-Q system providing CILA with 0.5% ropivacaine through two SilvaGard catheters placed in the retroperitoneal cavity and the rectus sheath, respectively. The case control group consisted of 40 donors matched with regard to sex, age, BMI and surgical technique. All donors were maintained on standardized multimodal analgesia combining nurse-controlled oxycodone treatment and acetaminophen. CILA donors had lower median cumulative consumption of morphine equivalents (CCME) (7 mg [0-56] vs. 42 mg [15-127]; p < 0.0000001), lower incidence of nausea (18 [45%] vs. 35 [87.5%] donors; p < 0.001), shorter time in postoperative care unit (160 vs. 242.5 min; p < 0.001) and shorter hospital stay (4 [4-7] vs. 6 [4-11] days; p < 0.001). In 32.5% of CILA donors the CCME was 0 mg (0% in matched control group, p < 0.001). CILA with 0.5% ropivacaine provides effective postoperative pain relief, reduces the need for opioid treatment and promotes postoperative recovery.

Factors influencing outcome of simultaneous kidney and pancreas transplantation: a 23-year single-center clinical experience.

INTRODUCTION: Simultaneous kidney and pancreas transplantation (SKPT) has become an effective treatment for patients who have diabetes mellitus type I with advanced nephropathy. This study assesses the progress of the SKPT program at Uppsala University Hospital, Sweden, and evaluates prognostic factors for graft survival. MATERIALS AND METHODS: Between February 1986 and September 2009, we performed 113 SKPT. The immunosuppression protocols changed over time and are defined as era 1, cyclosporine (CyA), atzathioprine (AZA) and steroids (C/A/S); era 2, C/A/S with antithymocyte globulin (ATG) induction (C/A/S/A); era 3, CyA, mycophenolate mofetic (MMF), steroids and ATG induction (C/M/S/A); era 4, tacrolimus (TAC), MMF, steroid, and ATG induction (T/M/S/A) and era 5, TAC, MMF, steroids and basiliximab induction (T/M/S/B). We analyzed donor/recipient/operative and postoperative variables to assess their influence on pancreas graft and patient survivals. RESULTS: The overall 1-, 5-, and 10-year patient survivals were 95.5%, 84.1%, and 65.5%, respectively. The 1-, 5-, and 10-year overall pancreas graft survivals were 77.6%, 58.4%, and 48.4%. The 1-, 5-, and 10-year pancreas graft survivals in SKPT patients transplanted between October 1997 and September 2009. (T/M/S/A and T/M/S/B; eras 4 and 5) were 95.3%, 72.7%, and 63.1%, respectively, which was significantly better than those of patients transplanted between February 1986 and September 1997 (era, 1 through 3) (P < 0.01, P < 0.0001, respectively). The quadruple regimen with TAC and MMF (eras 4 and 5) decreased the incidence of acute rejection episodes compared with eras 1 through 3 (P < 0.0001). Basiliximab induction (T/M/S/B; era 5) reduced the CMV infection rate compared with eras 1 through 4 (P < 0.01). Multivariate analysis revealed that donor age (younger than 40 years), immunosuppressive regimen with TAC and MMF (eras 4 and 5), and absence of acute rejection episodes independently affected pancreas graft survival. CONCLUSIONS: We demonstrate a superiority of the quadruple protocol with T/M/S/B for graft and patient survival with a decreased incidence of CMV infection after SKPT.

Hyaluronidase treatment of graft pancreatitis in rats: marked effects on the blood perfusion of the transplanted pancreas.

Hyaluronan is known to accumulate in tissues during inflammatory diseases associated with graft implantation and rejection of organ allografts. The aim was to evaluate whether hyaluronidase treatment affected hyaluronan content and blood perfusion in graft pancreatitis. Syngeneic rat pancreatic-duodenal transplantations were performed. Two days later blood flow measurements were made with a microsphere technique in both grafted and endogenous pancreas in animals treated with daily injections of vehicle or hyaluronidase (20.000 U/kg). Non-transplanted rats served as controls. Also, samples for analysis of hyaluronan and water content were taken. The hyaluronan content of the pancreatic graft was increased after transplantation. Hyaluronidase treatment markedly reduced total pancreatic and islet blood flow in both grafted and endogenous pancreas, whereas duodenum blood flow was unaffected. No blood flow effects were seen in non-transplanted control rats. Hyaluronan content was increased in the grafted pancreas, but hyaluronidase treatment decreased it to levels comparable to those of the endogenous gland. There were no differences in hyaluronan content in the endogenous pancreases of transplanted and non-transplanted rats. Graft pancreatitis after rat pancreas transplantation is associated with an increased hyaluronan content, which can be reduced by treatment with hyaluronidase. Hyaluronidase treatment of the graft recipients effected a 50% reduction in total pancreatic and islet blood flow in the graft, as well as in the endogenous pancreas. The functional importance of this is at present unknown.

Large-scale comparison of Liberase HI and collagenase NB1 utilized for human islet isolation.

For more than a decade Liberase HI was commonly used as the standard enzyme blend for clinical human islet isolation until enforced replacement by collagenase NB1 (NB1). This change resulted initially in a reduction in islet isolation outcome and transplant activities worldwide. This retrospective study was initiated to compare the efficiency of NB1 premium grade with Liberase in 197 human islet isolations. All pancreata were processed between January 2006 and June 2008 utilizing the same procedures for isolation and quality assessment except the administration of preselected lots of either Liberase (n = 101) or NB1 (n = 96). Utilizing Liberase, significantly more digested tissue and purified islet yield was produced compared to NB1. In contrast, the use of NB1 was associated with significantly higher purity and glucose stimulation index during dynamic perifusion. The expression of proinflammatory markers was almost identical except tissue factor expression, which was higher after utilization of Liberase. No difference was found in the percentage of pancreata fulfilling the criteria for clinical islet transplantation. The results suggest that Liberase is more efficient for pancreas dissociation than collagenase NB1 but seems to be more harmful to exocrine cells and islet tissue.

Positron emission tomography in clinical islet transplantation.

The fate of islets in clinical transplantation is unclear. To elude on this positron emission tomography combined with computed tomography (PET/CT) was performed for 60 min during islet transplantation in five patients receiving six transplants. A fraction of the islets (23%) were labeled with 18F-fluorodeoxyglucose ([(18)F]FDG) and carefully mixed with unlabeled islets just prior to intraportal transplantation. The peak radioactivity concentration in the liver was found at 19 min after start of islet infusion and corresponded to only 75% of what was expected, indicating that islets are lost during the transplantation procedure. No accumulation of radioactivity was found in the lungs. A nonphysiological peak of C-peptide was found in plasma during and immediately after transplantation in all subjects. Distribution in the liver was heterogeneous with wide variations in location and concentration. Islets found in areas with concentrations of >400 IEQ/cc liver tissue varied between 1% and 32% of the graft in different subjects. No side effects attributed to the PET/CT procedure were found. Clinical outcome in all patients was comparable to that previously observed indicating that the [(18)F]FDG labeling procedure did not harm the islets. The technique has potential to be used to assess approaches to enhance islet survival and engraftment in clinical transplantation.

Geographical prevalence, risk factors and impact of hepatitis B and C after renal transplantation.

BACKGROUND: Hepatitis B (HBV) and hepatitis C (HCV) virus infections are major risk factors affecting long-term morbidity and mortality after renal transplantation. Hepatitis prevalence is subject to geographical variations. OBJECTIVE: To compare and analyze the geographical prevalence, risk factors and impact of HBV and HCV infection in multinational cohorts of renal transplant recipients. METHODS: From 1989 - 2002, data on 12,856 kidney transplant recipients in 37 countries were collected within the prospective MOST (Multinational Observational Study in Transplantation). Subgroup analyses of hepatitis-related prevalence, risk factors and impact were conducted on patients whose HBV and HCV status was available at time of transplantation. Countries were substratified according to population prevalence of > or = 5% HBV or > or = 10% HCV. RESULTS: The prevalence of HBV was 2.9%, of HCV 8.7% and of HBV together with HCV 0.4%. Risk factors for hepatitis infection in renal transplant recipients were long dialysis time, retransplantation and blood transfusions. At each study endpoint up to 5 years after transplantation, no significant differences in graft function were observed, although the 1-year acute rejection rate tended to be lower in HCV+ patients. At 5 years post-transplant, there were no differences between the subgroups and regions regarding infections, post-transplant diabetes mellitus or malignancies including PTLD. CONCLUSIONS: Overall, HCV infections are more prevalent than HBV. Despite large geographical differences in prevalence, HBV and HCV status did not appear to have a significant impact on renal graft function, infections, malignancies and post-transplant diabetes mellitus up to 5 years after renal transplantation throughout the MOST countries.

The ethics of non-heart-beating donation: how new technology can change the ethical landscape.

The global shortage of organs for transplantation and the development of new and better medical technologies for organ preservation have resulted in a renewed interest in non-heart-beating donation (NHBD). This article discusses ethical questions related to controlled and uncontrolled NHBD. It argues that certain preparative measures, such as giving anticoagulants, should be acceptable before patients are dead, but when they have passed a point where further curative treatment is futile, they are in the process of dying and they are unconscious. Furthermore, the article discusses consequences of technological developments based on improvement of a chest compression apparatus used today to make mechanical heart resuscitation. Such technological development can be used to transform cases of non-controlled NHBD to controlled NHBD. In our view, this is a step forward since the ethical difficulties related to controlled NHBD are easier to solve than those related to non-controlled NHBD. However, such technological developments also evoke other ethical questions.

Optimising islet engraftment is critical for successful clinical islet transplantation.

Clinical islet transplantation is currently being explored as a treatment for persons with type 1 diabetes and hypoglycaemia unawareness. Although 'proof-of-principle' has been established in recent clinical studies, the procedure suffers from low efficacy. At the time of transplantation, the isolated islets are allowed to embolise the liver after injection in the portal vein, a procedure that is unique in the area of transplantation. A novel view on the engraftment of intraportally transplanted islets is presented that could explain the low efficacy of the procedure.

Antibody responses to xenogenic antigens--a study in the mouse-to-rat system.

Antibodies play a crucial role in the rejection of an organ that has been transplanted between different animal species, i.e. xenotransplantation. In previous work, we have induced a state of humoral tolerance where mouse-to-rat heart grafts continued to beat under ciclosporine A monotherapy. Initially, a combined treatment with ciclosporine A and 15-deoxyspergualin was given. This state of tolerance could not be reproduced when the vascularised heart graft was replaced with a free tissue graft or xenogeneic blood transfusions. To gain further insight into the humoral response against mouse antigens, we studied the antibody production in naive rats and rats challenged with heart transplants, heart cells, mononuclear cells (MNC) and erythrocytes from mice. Rats not challenged with any mouse cells or organs had a moderate amount of antibodies targeted against mouse MNC as well as rosette-forming cells in the spleen targeted against mouse erythrocytes. A challenge with either mouse MNC or erythrocytes lead to immunisation with antibodies of both IgM and IgG subtype directed against both MNC and erythrocytes. Antibody titres against mouse erythrocytes in animals challenged with MNC were not detectable until day 7, whereas antibody titres against mouse MNC in animals challenged with erythrocytes were detected on day 1. Immunisation with mouse erythrocytes raised the titre of rosette-forming cells in the spleen compared with naive rats (P < 0.05). Our data indicate that different xenogeneic antigens in the mouse-to-rat system are shared between heart cells, MNC and erythrocytes; however, the immunisation patterns differ regarding the time when antibodies are first detected.

Low 1-year cyclosporine microemulsion doses are associated with better 5-year renal graft function: an insight from MOST, a multinational observational study.

BACKGROUND: In earlier registry analyses, cyclosporine at doses of < 3 mg/kg/d at 1 year post-renal transplantation has been associated with significant graft loss or reduction in renal function. Improvements in cyclosporine formulation with increased bioavailability, plus the use of more efficient comedications, may now confer better outcomes. To determine the effect of the 1-year cyclosporine microemulsion (CsA-ME) dose on renal allograft function at 5 years, we analyzed data collected from 2889 patients with documented graft survival to year 5 in a prospective, multinational, observational study-Neoral MOST. RESULTS: Glomerular filtration rate (GFR) at year 1 was 63 +/- 20 mL/min and 59 +/- 22 mL/min at year 5. The multivariate analysis including year 1 CsA-ME dose as factor and GFR at 1 year as covariate revealed the most significant factors affecting GFR at year 5 were 1-year GFR, donor age > 60 years, and CsA-ME dose at 1 year. Risk factors associated with reduction in 5-year GFR (<65 mL/min) included donor or recipient age >60 years, delayed graft function, cadaveric donor, previous graft, and acute rejection. CsA-ME dose <3 mg/kg/d was found to protect GFR. Analysis of GFR at each year posttransplantation (Wilcoxon model) found 1-year CsA-ME (cutoff 3 mg/kg/d) had a significant effect at each time point. CONCLUSIONS: Compared to higher doses, CsA-ME <3 mg/kg/d at year 1 posttransplantation is associated with increased preservation of renal allograft function at year 5.

Impact of mycophenolate mofetil dose posttransplantation on 12-month renal function: analysis of the MOST database.

INTRODUCTION: Mycophenolate mofetil (MMF) has greatly reduced the risk of acute rejection episodes (ARE) after renal transplantation, but dose reductions/withdrawals could jeopardize long-term results. METHODS: The MOST database of "de novo" patients treated with MMF at month 1 and functioning grafts at month 12 were divided into 2 groups: groups 1, 2 g MMF at month 1 and month 12; and group 2, 2 g MMF at month 1 but MMF <2 g at month 12 to evaluate renal function glonerular filtration rate (GFR). RESULTS: In this study, 1136 patients were receiving 2 g MMF at month 1. On month 12, 645 were on 2 g (56.8%, group 1) and 431 were on <2 g (43.2%, group 2). Group 1 included younger recipients of younger donors with fewer patients with delayed graft function (DGF). Group 1 showed more ARE during month 1 and more patients who received induction. Mean Neoral daily doses at month 1/month 12 were 5.3/3.0 and 5.3/3.1 mg/kg in group 1 and group 2, respectively (P = .05 at month 12). GFR in group 1 and group 2 were 59.06 (CI 57.10-60.60) and 53.81 (CI 52-55.7) at month 1 (P < .001); 63.7 (CI 62.1-65.30) and 55.9 (CI 54.1-57.7) mL/min*1.73 m(2) at month 12 (P < .001). The mean increases in GFR between month 1 and month 12 were 4.64 and 1.94 mL/min*1.73 m(2), respectively (P < .05). A multivariate analysis also included 795 patients from the "maintenance" patient database with retrospective detailed information. The following parameters were highly predictive for good renal function at month 12: donor age younger than 60 years, recipient age younger than 60 years, immediate graft function, 12-month MMF dose = 2 g, absence of CMV infection, and 12-month Neoral dose <3 mg/kg/d. CONCLUSIONS: Maintenance of MMF dose at 2 g/d during the first year appears to facilitate the attainment of optimal renal function at 12-months after kidney transplantation.

Current status of clinical islet transplantation.

Islet transplantation is currently being explored as a treatment for patients with type 1 diabetes. At present, the number of patients becoming insulin-independent is rapidly increasing world-wide applying the transplantation protocol originally described by the group in Edmonton. A hallmark in this procedure is repeated infusions of islets obtained from 2 to 4 donors until normoglycemia is achieved. In order to establish islet transplantation as a widely accepted treatment modality, and make tolerance induction regimes applicable, it is essential that the donor:recipient ratio is brought down to 1:1. A conceivable strategy to achieve this goal in clinical islet transplantation is discussed.

Delayed graft function: risk factors, consequences and parameters affecting outcome-results from MOST, A Multinational Observational Study.

BACKGROUND: Delayed graft function (DGF) is a common complication after renal transplantation, and may affect graft function. The aim of this analysis was to evaluate risk factors for DGF, as well as parameters and events influencing graft function after DGF. We analyzed data collected in an ongoing international, prospective; observational study, the Neoral-MOST (Multinational Observational Study in renal Transplantation), and included in the analysis all patients with cadaveric kidney transplants for whom renal function at 1 year posttransplantation was documented (N = 8950). Logistic regression was used to evaluate the risk factors for DGF occurrence, and multifactorial analysis of variance (ANCOVA) to assess the relevance of different factors for GFR at 1 year. RESULTS: Higher donor age, longer CIT, male recipients, Caucasian recipients, high recipients body mass index, and PRA were all associated with a higher risk for DGF. Renal function of former DGF kidneys at 1 year was lower in kidneys of elder donors, or which had experienced rejection or CMV infection. Variations of the maintenance regimen at 1 year posttransplantation were not associated with better graft function. Multifactorial analysis showed donor age and acute rejection as significant independent factors. CONCLUSIONS: Most factors increasing the risk for DGF or having a negative impact on renal function at 1 year in grafts with DGF are predetermined. Additional posttransplant damage by acute rejection was associated with further reductions in GFR. Preventing acute rejection is an important step in achieving optimal function of DGF grafts.

Key factors for human islet isolation and clinical transplantation.

BACKGROUND: To further improve the outcome of clinical islet transplantation analysis of the impact of donor- and process-related factors could be of great importance. MATERIALS AND METHODS: Thirty-eight consecutive clinical islet transplantations were performed with consecutive islet isolations. Univariate analysis for donor- and isolation-related variables were correlated with recipient C-peptide levels at 2 and 4 weeks after transplantation. "Warm ischemia time" was defined as the time from start of University of Wisconsin solution perfusion in the donor until the pancreas was removed to the back table. RESULTS: Short "warm ischemia time" (WIT), low expression of tissue factor (TF) in pancreatic tissue, and high creatinine levels in the donor were variables related to high C-peptide values after islet transplantation. Furthermore, hospitalization length longer than 4 days was associated with low C-peptide levels. The number of islet equivalents (IEQ) did not correlate with the clinical outcome, possibly due to the fact that IEQ number was included in the release criteria for clinical islet transplantation CONCLUSIONS: Successful clinical islet transplantation is strongly correlated with donor and pancreas procurement factors rather than isolation process-related variables. "WIT" may induce TF expression in the pancreatic tissues. TF has been identified as the main trigger of the instant blood-mediated-inflammatory reaction in clinical islet transplantation. Therefore, assay of TF expression in pancreatic tissues could be applied as useful screening tool to identify "good" pancreata for clinical transplantation.

Effects of commonly used immunosuppressants on graft-derived fibroblasts.

In acute rejection of transplanted organs intragraft fibroblasts increase their production of hyaluronan. Hyaluronan has strong water binding capacity and an increased tissue content of hyaluronan thus contributes to the development of interstitial oedema. The present study examined the effects of commonly used immunosuppressants (prednisolone, cyclosporin, tacrolimus, mycophenolic acid and sirolimus) on fibroblast proliferation, hyaluronan production and cell surface receptor expression. Fibroblasts isolated from rejecting tissue and from normal, non-transplanted tissue were studied in parallel. All substances investigated, except tacrolimus, were found to affect fibroblasts in one way or another. The most striking effect was the almost total inhibition of fibroblast proliferation in the presence of mycophenolic acid. Cyclosporin reduced the proliferation by about 50% and prednisolone had an inhibiting effect on hyaluronan production (50% reduction). These effects were observed on fibroblasts isolated from rat cardiac allografts undergoing rejection as well as on fibroblasts obtained from normal heart tissue. In contrast, sirolimus was found to stimulate the proliferation of fibroblasts from rejecting tissue (100% increase), but not that of normal fibroblasts. The majority of the fibroblasts expressed the hyaluronan receptor CD44, with a more intense expression in cultures of fibroblasts derived at rejection. None of the immunosuppressants affected the staining pattern (number of positive cells or intensity). The inhibitory effects of prednisolone, cyclosporin and mycophenolic acid on fibroblasts may contribute to the overall beneficial effects of these drugs when used for prevention or treatment of rejection.

One-year posttransplant renal function is a strong predictor of long-term kidney function: results from the Neoral-MOST Observational Study.

BACKGROUND: Peritransplant risk factors influence short-term and long-term graft survival, and 1-year serum creatinine is known to predict long-term graft survival. To examine interrelationships between risk factors, renal function at 1 year, and long-term graft function in patients maintained on cyclosporine, we analyzed data collected from 10,692 de novo or maintenance renal transplant recipients in an ongoing international, prospective, observational study--Neoral-MOST (Multinational Observational Study in renal Transplantation). The effect of donor age, delayed graft function, acute rejection, donor type, panel-reactive antibodies, and previous graft on 1- and 5-year renal function and their relationship to 1-year serum creatinine was assessed. RESULTS: Donor age, delayed graft function, acute rejection, and donor type significantly increased the risk for serum creatinine > 130 micromol/L at 1 year posttransplant, and 1-year serum creatinine was the strongest predictor of 5-year renal function. After adjustment for 1-year serum creatinine, an ongoing influence was observed for donor age, donor type, and previous graft. Delayed graft function and acute rejection had a significant effect on serum creatinine at year 1 but no additional impact on long-term graft function. CONCLUSIONS: Serum creatinine at 1 year is influenced by risk factors known to affect overall graft survival and is predictive of 5-year renal graft function. The effects of delayed graft function and acute rejection appear to be limited to their influence on serum creatinine at 1 year, whereas donor type and previous graft predominantly affect later stages of graft life.