Tacrolimus predose concentrations do not predict the risk of acute rejection after renal transplantation: a pooled analysis from three randomized-controlled clinical trials(†).

Therapeutic drug monitoring (TDM) for tacrolimus (Tac) is universally applied. However, the concentration-effect relationship for Tac is poorly defined. This study investigated whether Tac concentrations are associated with acute rejection in kidney transplant recipients. Data from three large trials were pooled. We used univariate and multivariate analysis to investigate the relationship between biopsy-proven acute rejection (BPAR) and Tac predose concentration at five time points (day 3, 10 and 14, and month 1 and 6 after transplantation). A total of 136/1304 patients experienced BPAR, giving an overall incidence of 10.4%. We did not find any significant correlations between Tac predose concentrations and the incidence of BPAR at the different time points. In the multivariate analysis, only delayed graft function (DGF) and the use of induction therapy were independently correlated with BPAR, with an odds ratio of 2.7 [95% CI: 1.8-4.0; p < 0.001] for DGF and 0.66 [95% CI: 0.44-0.99; p = 0.049] for induction therapy. The other variables, including the Tac predose concentrations, were not statistically significantly associated with BPAR. We did not find an association between the Tac predose concentrations measured at five time points after kidney transplantation and the incidence of acute rejection occurring thereafter. Based on this study it is not possible to define the optimal target concentrations for Tac.

Prevention of acute and chronic allograft rejection by combinations of tolerogenic dendritic cells.

It is well known that adoptive transfer of donor-derived tolerogenic dendritic cells (DC) helps to reduce acute allograft rejection. However, this method cannot effectively prevent grafts from infiltration of inflammatory cells and fibrosis, and thus has minimal effect on chronic allograft rejection. In this study, we used mitomycin C (MMC) to generate tolerogenic DC and demonstrated that donor (Balb/c)-derived MMC-DC could induce hyporesponsiveness of recipient (C57BL/6) T cells in vitro, potentially by inducing T-cell apoptosis, decreasing IL-2 and IL-12 secretion, and increasing regulatory T-cell numbers and IL-10 secretion. Furthermore, anti-CD154 monoclonal antibody (mAb) treatment combined with donor-derived MMC-DC prolonged the survival of the allografts in vivo. The mechanisms were similar to those in vitro. Impressively, both acute and chronic rejection were prevented when donor and F1 generation (Balb/c × C57BL/6) derived MMC-DC were injected together with anti-CD154 mAb into recipients before heart allotransplantation. In summary, we showed that donor and F1-derived tolerogenic DC have a synergistic effect on induction and maintenance of T-cell regulation and the secretion of immunosuppressive cytokines. Moreover, adoptive transfer of these two types of DC could inhibit both acute and chronic transplant rejection in mice.

Small islets are essential for successful intraportal transplantation in a diabetes mouse model.

Optimization of islet transplantation protocols is necessary for improved success of treatment for type 1 diabetes. Here, we investigated whether the size of islets transplanted into the portal vein (PV) of the liver can affect engraftment in the early post-transplantation in an experimental mouse model. Small (average diameter < 250 µm, group A) or large (average diameter > 250 µm, group B) islets (400 islet equivalents/recipient) purified from normal BALB/c mice were transplanted into syngenic recipients with diabetes induced by STZ. The percentage of mice returning to a non-diabetic status was higher in group A (100%) than that of group B (62.5%). Focal areas of liver necrosis associated with the islets emboli were observed in both groups, but the pathology in group B was significantly worse. Multiple proinflammatory cytokines were significantly higher in group B than that of A at 3 h post-transplantation. Our study determined that the size of islets plays a critical role in the success of intraportal islet transplantation (IPIT) and should be taken into account in future IPIT protocols for the treatment of diabetes.

Subgroup analyses in randomized controlled trials: the need for risk stratification in kidney transplantation.

Although randomized controlled trials (RCT) are the gold standard for establishing causation in clinical research, their aggregated results can be misleading when applied to individual patients. A treatment may be beneficial in some patients, but its harms may outweigh benefits in others. While conventional one-variable-at-a-time subgroup analyses have well-known limitations, multivariable risk-based analyses can help uncover clinically significant heterogeneity in treatment effects that may be otherwise obscured. Trials in kidney transplantation have yielded the finding that a reduction in acute rejection does not translate into a similar benefit in prolonging graft survival and improving graft function. This paradox might be explained by the variation in risk for acute rejection among included kidney transplant recipients varying the likelihood of benefit or harm from intense immunosuppressive regimens. Analyses that stratify patients by their immunological risk may resolve these otherwise puzzling results. Reliable risk models should be developed to investigate benefits and harms in rationally designed risk-based subgroups of patients in existing RCT data sets. These risk strata would need to be validated in future prospective clinical trials examining long-term effects on patient and graft survival. This approach may allow better individualized treatment choices for kidney transplant recipients.

Calcineurin inhibitor minimization in the Symphony study: observational results 3 years after transplantation.

The Symphony study showed that at 1 year posttransplant, a regimen based on daclizumab induction, 2 g mycophenolate mofetil (MMF), low-dose tacrolimus and steroids resulted in better renal function and lower acute rejection and graft loss rates compared with three other regimens: two with low-doses of cyclosporine or sirolimus instead of tacrolimus and one with no induction and standard cyclosporine dosage. This is an observational follow-up for 2 additional years with the same endpoints as the core study. Overall, 958 patients participated in the follow-up. During the study, many patients changed their immunosuppressive regimen (e.g. switched from sirolimus to tacrolimus), but the vast majority (95%) remained on MMF. During the follow-up, renal function remained stable (mean change: -0.6 ml/min), and rates of death, graft loss and acute rejection were low (all about 1% per year). The MMF and low-dose tacrolimus arm continued to have the highest GFR (68.6 +/- 23.8 ml/min vs. 65.9 +/- 26.2 ml/min in the standard-dose cyclosporine, 64.0 +/- 23.1 ml/min in the low-dose cyclosporine and 65.3 +/- 26.2 ml/min in the low-dose sirolimus arm), but the difference with the other arms was not significant (p = 0.17 in an overall test and 0.077, 0.039 and 0.11, respectively, in pair-wise tests). The MMF and low-dose tacrolimus arm also had the highest graft survival rate, but with reduced differences between groups over time, and the least acute rejection rate. In the Symphony study, the largest ever prospective study in de novo kidney transplantation, over 3 years, daclizumab induction, MMF, steroids and low-dose tacrolimus proved highly efficacious, without the negative effects on renal function commonly reported for standard CNI regimens.

Improvement of canine pancreas-allograft survival with diagnosis of rejection by fine-needle aspiration biopsy.

Early diagnosis of rejection in pancreas-allograft transplantation remains a clinical challenge. The aim of this study was to assess the ability of antirejection therapy to reverse rejection when the diagnosis was based on either fine-needle aspiration biopsy (FNAB) or urinary amylase (UA). Sixteen dogs received a total-pancreas allograft with exocrine drainage into the bladder. Initially, a deliberately low dose of cyclosporin was given. Monitoring included percutaneous FNAB with ultrasound guidance and fasting spot measurements of UA. The diagnosis of rejection was made in alternate dogs when UA fell to less than 5000 IU/L (group A) or when the total corrected increment (TCI) of aspirated infiltrating cells was greater than 2.6 (group B). Antirejection therapy consisted of 10 mg.kg-1.day-1 i.v. methylprednisolone for 5 days and an increased dose of cyclosporin (25 mg.kg-1.day-1). The median allograft survival was 9 days (range 8-19) in group A and 32 days (range 10-63) in group B (P = .01). A fall in UA permitted the successful reversal of rejection in only one of six grafts, whereas five of seven grafts were successfully treated when rejection diagnosis was based on FNAB. In conclusion, early diagnosis of rejection was achieved by FNAB, improving the ability of antirejection therapy to reverse pancreas-allograft rejection and prolong survival.

Differential expression of tissue factor (TF) in calcineurin inhibitor-induced nephrotoxicity and rejection--implications for development of a possible diagnostic marker.

Deposition of fibrin in the form of fibrinoid necrosis is a common feature of severe acute renal allograft rejection. The role of the coagulation system and its initiator tissue factor (TF) during this process is, however, still poorly understood. In this study, we analyzed the expression of TF in 88 renal transplants afflicted with different forms of rejection and calcineurin inhibitor-induced nephrotoxicity, to see whether there was differential expression of this protein. TF immunoreactivity was evaluated semiquantitatively in six different renal structures: the podocytes, Bowman epithelium, the endothelium of the glomeruli, the brush border of tubular cells, the thin ascending loop of Henle, and small arteries/arterioles. The TF expression of normal renal tissue (n=6) was restricted to the glomerular podocytes and Bowman epithelium, and to some extent the ascending loop of Henle. Renal allografts undergoing acute rejection (AR) of grades I-III, (n=13, n=17 and n=12, respectively) did not show any altered TF expression in the glomeruli or vascular endothelium. In the ascending loop of Henle, a reduced expression could be seen (ARI, p=0.015; and ARII, p=0.043). TF staining of the brush border of renal transplants undergoing acute cyclosporin A (CsA) nephrotoxicity (n=18) was significantly higher than in normal kidneys (p=0.0003), as well as in transplants undergoing various degrees of acute rejection (ARI, p=0.027; ARII, p=0.0012; and ARIII, p=0.0001). Tubular brush border-expressed TF was also evident in 10 of 15 allografts suffering from chronic CsA nephrotoxicity, compared to 4 out of 13 cases with chronic allograft vasculopathy (CAV), but the increase was not statistically significant relative to normal kidneys. The majority of the grafts afflicted with either of the two chronic conditions displayed a TF-positive arterial endothelium (CAV, p=0.0034; and chronic CsA nephrotoxicity, p=0.0026) relative to controls. In conclusion, these results indicate that vascular TF expression is not altered during acute rejection, but may be of importance in chronic allograft nephropathy. Furthermore, TF immunoreactivity in the tubular brush border may be specific to acute CsA nephrotoxicity and might be used as a biomarker for this condition. Further studies are required to evaluate the possible role of brush border-expressed TF in the pathogenesis of CsA nephrotoxicity.

Factor V R506Q mutation (activated protein C resistance) is an additional risk factor for early renal graft loss associated with acute vascular rejection.

BACKGROUND: The factor V R506Q mutation (FV R506Q, FV:Q506, or FV Leiden) resulting in activated protein C (APC) resistance is the most common inherited risk factor for venous thrombosis, including in renal transplant recipients. We investigated a possible association between the FV mutation and early renal graft loss, and the prevalence of macro- and microvascular thrombosis, endothelialitis, and fibrinoid vascular necrosis by FV genotype. METHOD: One hundred and nine renal allograft recipients were genotyped for FV mutation. A vascular rejection subgroup of patients (n=29) had experienced at least one episode of vascular rejection, or graft thrombosis. A second group of patients (n=80) had experienced no acute rejection and retained a well-functioning graft. RESULTS: The prevalence of APC resistance was numerically but not statistically significantly higher in the vascular rejection group (17.2%) compared with the group without rejection episodes (7.5%) (P=0.16). There was a significant association between the presence or absence of FV mutation and graft survival, with a 55.6% 1-year graft survival rate versus a 76.4% rate, respectively (P=0.02). The prevalence of vascular rejection, as evidenced by endothelialitis or fibrinoid vascular necrosis, was significantly associated with APC resistance but macro- or microvascular thrombosis were not. CONCLUSION: Renal transplant recipients who are carriers of the FV:Q506 allele have an increased risk of early graft loss. Vascular rejection changes including endothelialitis and fibrinoid vascular necrosis were more common in this group, and therefore an association between the hypercoagulable state, which entails an up-regulation of the mitogenic and proinflammatory enzyme thrombin, and the immunological challenge to the endothelium may be the cause of inferior prognosis in these patients.

Proportion of glomerulosclerosis in procurement wedge renal biopsy cannot alone discriminate for acceptance of marginal donors.

BACKGROUND: The shortage of available kidneys for renal transplantation could be addressed, to some extent, by expanding the criteria for acceptance of marginal donors. The study of these criteria is limited by the selection of grafts actually retrieved and transplanted, therefore reduced to a study of risk factors. We have evaluated the potential of procurement renal biopies as an instrument for acceptance or refusal of donor kidneys for transplantation. METHODS: This was a prospective study of a consecutive series of 200 donors. Biopsies were performed by wedge technique at the donor operation and were evaluated for proportion of glomerulosclerosis, vascular and tubular changes, and interstitial fibrosis. The study included 387 renal grafts with a representative biopsy, transplanted, and followed-up for survival and functional evaluation; 24 hr creatinine clearance at 1 and 3 weeks, and 3, 6, 12, 18, and 24 months. RESULTS: Factors associated with initial graft function included cold ischemia time, number of DR mismatches, tubular changes, although donor age showed the strongest correlation with short- and long-term level of graft function. DR mismatches and retransplantation appeared to be the only significant risk factors for graft loss. The proportion of glomerulosclerosis (mean 8%, range 0-48%) correlated with graft function in the simple regression analysis. However, when age was taken into account glomerulosclerosis did not correlate significantly with graft function. Furthermore, glomerulosclerosis as high as 25% or more had an acceptable 3-year graft survival rate of 74.7%. CONCLUSION: Procurement biopsy provides only limited information for the decision whether or not to accept a kidney donor.

Double-blind comparison of two corticosteroid regimens plus mycophenolate mofetil and cyclosporine for prevention of acute renal allograft rejection.

BACKGROUND: Renal transplant recipients experience adverse events attributed to corticosteroid therapy. METHODS: This was a multicenter, randomized, double-blind, 6-month, controlled steroid dose-reduction study in renal transplant recipients with an unblinded 6-month follow-up. In the low/stop arm, corticoste. roids were given at half the dosage of control for 3 months from the date of transplantation, and then withdrawn. Both arms received mycophenolate mofetil and cyclosporine. The primary endpoint was the incidence of biopsy-proven acute rejection at 6 months posttransplantation. RESULTS: There were 248 patients in the control group and 252 in the low/stop group. At 6 months the low/stop group had more biopsy-proven acute rejection episodes than the control (23% vs. 14%; P=0.008). At 12 months this increased to 25% vs. 15%. Most rejections were Banff grade I. Twelve-month graft loss was 5% in the low/stop group vs. 4% in the control. At 6 and 12 months serum cholesterol (P<0.01, P<0.01), triglycer. ides (P<0.01, P<0.01), and systolic blood pressure (P<0.001, P<0.001) were lower in the low/stop group. Diastolic pressure was lower (P<0.01) and lumbar spine bone density was greater (P<0.01) in the low/ stop group at 12 months. CONCLUSIONS: In renal transplant recipients treated with mycophenolate mofetil and cyclosporine, reduction and early withdrawal of the prophylactic corticosteroid dose is feasible without an unacceptable increase in serious rejection episodes. This is accompanied by a significant reduction of steroid-related adverse events.

The effect of venous drainage on glucose homeostasis after experimental pancreas transplantation.

In this canine study, glucose homeostasis after clinical pancreas transplantation is complex, with the relative effect of systemic versus portal delivery of insulin remaining unresolved. Thirty-two pancreatectomized dogs received either systemic venous drainage (SVD) with bladder exocrine drainage (n = 16), or portal venous drainage (PVD) with gastric exocrine drainage (n = 16). Cyclosporine (CsA) based immunosuppression was commenced on day -7. The effect of immunosuppression was a significant increase in fasting blood glucose (FBGL) (P = 0.002), fasting insulin (P = 0.024), AUC for insulin (P = 0.009), and K values decreased (P = 0.009). FBGL and K values remained abnormal after transplantation with no significant difference seen between SVD and PVD. However, fasting insulin became significantly lower after PVD and AUC insulin fell in both groups. CsA levels fell in both groups after transplantation, mirroring the fall in AUC insulin, and implicating CsA as a major cause of peripheral resistance to insulin. In conclusion, PVD did not demonstrate a significant advantage over SVD in handling an intravenous glucose challenge. The need for pancreatectomy in large animals may make them an unsatisfactory experimental model to evaluate the glucoregulatory effects of pancreas allotransplantation.

Activation of alloreactive natural killer cells is resistant to cyclosporine.

BACKGROUND: We have previously shown that cytotoxic T lymphocytes (CTL) with alloreactivity were induced when Wistar Furth (WF; RT1u) rats were immunized with allogeneic Brown Norway (BN; RT1n) cells. In contrast, when BN rats were immunized with WF cells, the allospecific response was confined to alloreactive natural killer (NK) cells, and no CTL activity was observed. In this study, the effect of cyclosporine (CsA) on the activation of alloreactive NK cells in vivo was analyzed. METHODS: Distinct peritoneal effector cells from rats immunized with allogenic cells with or without concomitant CsA and/or interleukin (IL) 2 treatment were tested for specific cytolytic activity. Furthermore, the presumptive role of NK cells in rejection immunity was addressed in a cardiac graft model. RESULTS: The results showed that doses of CsA that completely inhibited the activation of alloreactive CTL, only marginally affected the activation of alloreactive NK cells. We also showed that CsA treatment failed to prolong graft survival in BN recipients of WF hearts. Treatment of BN rats with CsA/IL-2 during immunization with allogeneic WF cells resulted in concomitant induction of alloreactive NK cells and alloreactive CTL. CONCLUSIONS: We have demonstrated that CsA failed to suppress the activation of alloreactive NK cells. Consequently, the cardiac graft survival in the donor-recipient combination known to activate alloreactive NK cells was not significantly prolonged by CsA treatment, emphasizing the involvement of NK cells as effectors in organ rejection. Furthermore, the parallel emergence of alloreactive NK cells and CTL only in the presence of CsA/IL-2 indicated that CsA interfered with alloreactive NK cell-associated suppression of CTL activated by allogeneic tissue.

Long-term duct-occluded segmental pancreatic autografts. Does fibrosis lead to graft loss?

In clinical pancreas transplantation, duct-occluded segmental allografts are often used. There is concern that fibrosis following duct-occlusion may lead to progressive graft failure. In this study, sequential histology and endocrine function in long-term (up to 5 years) canine autografts were assessed. Segmental pancreatic autografts with residual pancreatectomy were performed, and the pancreatic duct was occluded with cyanoacrylate glue. Serial i.v. glucose tolerance tests (IVGTT) and percutaneous needle-core biopsies of the grafts were performed as long as grafts functioned. Ten dogs were long-term (greater than 18 months) survivors: 8 dogs had functioning grafts for a median of 48 months (range 18-60) after transplantation, and 3 dogs had graft failure at 21, 27, and 60 months. The mean 40-min blood glucose concentration (BGL-40') after i.v. glucose injection did not increase with time up to 5 years after grafting. Graft biopsies showed a universal picture of aggregated islet cells and fibrous replacement of acinar tissue. The total amount of fibrosis did not change with time, but the existing fibrosis became less cellular and more dense. This long-term study showed that in autografted animals, adequate endocrine function was maintained in the majority of cases, and progressive replacement of islet tissue by fibrosis could not be demonstrated in serial biopsies taken between 18 months and 5 years after autotransplantation. We therefore conclude, that while duct-occlusion results in extensive fibrosis, the process is not progressive, and although fibrosis may contribute to late graft failure this is not inevitable.

Simultaneous pancreas and kidney transplant rejection: separate or synchronous events?

The results of simultaneous pancreas and kidney transplantation (SPK) cannot be matched by pancreas transplantation alone (PTA), in part because an independent diagnosis of pancreas graft rejection remains difficult. The relationship between rejection of the pancreas and rejection of the kidney is poorly understood, and it is not known whether simultaneous transplantation of both organs confers true protection to either graft. To study these questions, reliable canine allotransplant models of kidney transplantation alone (KTA), PTA, and SPK were established. Sixty-seven mongrel dogs received KTA (n=21), PTA (n=23), or SPK (n=23) with either no immunosuppression, low-dose cyclosporine (CsA)-based immunosuppression, or high-dose CsA-based immunosuppression. Needle core biopsy (NCB) and fine needle aspiration biopsy (FNAB) were performed at 0, 2, 4, 7, 9, 11, 14, 21, and 30 days or at the time of graft failure. Pancreas and kidney graft survival after SPK was significantly shorter in dogs given low-dose CsA than in dogs given high-dose CsA (pancreas, P<0.04; kidney, P<0.03). Concurrent NCBs and FNABs were performed on 227 occasions in pancreas grafts and 229 occasions in kidney grafts. The time to initial evidence of rejection by NCB was not different in any immunosuppressed group. Synchronous rejection occurred in 73% of immunosuppressed SPK biopsies. Kidney-only rejection occurred in 23% of biopsies and pancreas-only rejection occurred in only 3% after SPK. All markers of pancreas graft rejection were poor, with the most sensitive being NCB of the simultaneously transplanted kidney. In summary, recipients of SPK required more immunosuppression than recipients of PTA, and improved PTA survival should be achievable with more sensitive markers of rejection. Markers of kidney rejection were the most sensitive indicators of pancreas rejection, and independent pancreas rejection was uncommon after SPK.

Experimental hyperacute rejection in pancreas allotransplants.

A model of sensitization by intraperitoneal lymph node inoculation was developed to test the hypothesis that hyperacute rejection (HAR) could occur in sensitized recipients of vascularized pancreas allografts. Ten pairs of outbred mongrel dogs that were lymphocytotoxic cross-match assay negative were inoculated with homogenized lymph nodes on either three or four occasions at fortnightly intervals before renal transplantation. A renal allograft from the same donor was used to test the HAR response and to further enhance sensitization by rejection of a vascularized organ. Pancreas transplants were performed 2 weeks later, with biopsies of the graft and blood samples taken at 0, 10, 20, and 30 min and then at 30-min intervals until the grafts were no longer viable. All renal and pancreas grafts were rejected in a classical hyperacute pattern. Within 4 min of revascularization of the pancreas, central lobular hemorrhage and vascular congestion appeared, followed by general edema. Histology demonstrated parallel changes of edema, vascular congestion, necrosis, hemorrhage, and leukocytic infiltrate, which all preceded graft infarction. A sharp decline in both arterial and venous white blood cell count and platelets occurred within 10 min of revascularization with initial sequestration and subsequent release of platelets from the graft (P=0.02). In summary, HAR of the allografted pancreas can be observed by the surgeon within minutes of revascularization, with predictable macroscopic and microscopic changes. This study supports the use of routine lymphocytotoxic cross-match tests for all recipients of pancreas transplants and implies that particular care is warranted in regraft pancreas allograft recipients.

Long-term duct-occluded segmental pancreatic autografts: absence of microvascular diabetic complications.

BACKGROUND: Current insulin therapies for control of glucose metabolism in patients with type I diabetes mellitus prevent major metabolic consequences of insulin deficiency, but none prevents or arrests long-term complications. In experimental models of canine diabetes, retinopathy, neuropathy, and nephropathy have been shown to develop within 5 years. The aim of this study was to determine in a canine model whether glucose control provided by segmental duct-occluded pancreas autografts could prevent the long-term complications of diabetes. METHODS: Thirty-five outbred mongrel dogs underwent segmental pancreas autotransplantation with residual pancreatectomy. Follow-up over 5 years included endocrine, retinal fundus photography, fluorescein angiography, and nerve conduction studies. At endpoint, analysis of organ specific changes was undertaken. RESULTS: Long-term survival was achieved in 14 dogs for 4 to 5 years and in 3 dogs for 3 to 5 years. Glycosylated hemoglobin levels remained within normal limits, although response to glucose challenge was suboptimal. Fundus photography and fluorescein angiography demonstrated the absence of retinal vascular aneurisms, capillary leakage, and obliteration. Retinal digest showed no vascular changes and normal endothelial/pericyte ratios. Nerve conduction was normal, and histology of nerves revealed normal density of myelinated fibers and absence of intrafascicular vessels and glycogen deposits, with no change in spectrum of fiber diameters and ovoids. Renal histology revealed no evidence of nephropathy with normal glomerular basement membranes. CONCLUSIONS: We have demonstrated that duct-occluded segmental pancreatic autografts are capable of providing satisfactory metabolic control for up to 5 years, thereby preventing development of the long-term microvascular complications of diabetes.

The use of pretransplant erythropoietin to normalize hemoglobin levels has no deleterious effects on renal transplantation outcome.

BACKGROUND: The aim of this study was to establish the outcome of renal transplantation in patients given pretransplant erythropoietin (EPO) treatment targeted at reaching a normal hemoglobin concentration (Hb), compared to those given EPO-treatment aimed at maintaining subnormal Hb. METHODS: A total of 416 patients from Scandinavian countries and with renal anaemia were enrolled to examine the effects of increasing Hb from a subnormal level (90-120 g/liter) to a normal level (135-160 g/liter) by EPO treatment. Half of the patients were randomized to have their Hb increased, with the other half randomized to maintain a subnormal Hb. Thirty-two patients from the normal Hb group and 24 patients from the subnormal group received a renal graft during the study period. The outcomes of these transplantations were examined prospectively for 6 months. RESULTS: Preoperative Hb levels were 143+/-17 and 121+/-14 g/liter in the two groups, respectively (P<0.0001). The Hb remained higher in the normal Hb group during the first 2 weeks after transplantation. The percentage of patients requiring postoperative blood transfusions in the normal Hb group was 16%, compared with 50% in the subnormal group (P<0.01). No statistically significant difference in the proportion of functioning grafts or in the serum creatinine levels could be detected. No correlation between EPO treatment and creatinine levels after transplantation was found. The frequency of adverse events was similar in the two groups. CONCLUSIONS: EPO treatment aimed at reaching a normal Hb in renal transplant recipients reduces the postoperative requirement for blood transfusions and has no deleterious effects on kidney graft function.

Multicenter trial exploring calcineurin inhibitors avoidance in renal transplantation.

BACKGROUND: The adoption of calcineurin inhibitors (CNI) as the mainstay of immunosuppression has resuited in a significant decrease of acute rejection and improvement of short-term graft survival. However, because of the irreversible nephrotoxicity associated with the chronic use of the CNI, the magnitude of the improvement of long-term graft survival has been more modest. Therefore, an effective immunosuppression regimen that does not rely on CNI may result in improvement of long-term outcome and simplification of the management of transplant recipients. METHODS: Ninety-eight patients of primary cadaver or living donor kidneys at low immunologic risk were enrolled in a CNI avoidance study. The immunosuppression regimen consisted of daclizumab, a humanized monoclonal antibody that binds to the alpha chain of the interleukin-2 receptor (IL-2Ralpha), administered for a total of five doses at biweekly intervals; 3 gm/day mycophenolate mofetil for the first 6 month and 2 gm thereafter; and conventional corticosteroid therapy. Patients who underwent rejection episodes could be started on CNI. The primary efficacy end-point was biopsy-proven rejection during the first 6 months posttransplant. RESULTS: Biopsy-proven rejection was diagnosed in 48% of patients during the first 6 months after transplantation. The majority of rejection episodes were Banff grade I and IIA and were fully reversed with corticosteroid therapy. The median time to the first biopsy-proven rejection among patients who experienced this event during the first 6 months was 39 days. In 22 patients with delayed graft function, the proportion of patients with biopsy-proven rejection was 50% at 6 months. However in the first 2 weeks posttransplant, only 1 of 22 patients with delayed graft function developed biopsy-proven rejection. At 1 year, patient survival was 97% and graft survival was 96%. Only two grafts were lost secondary to rejection. At 1-year posttransplant, 62% of patients had received CNI for more than 7 days. At 1-year posttransplant, the mean serum creatinine in the nonrejectors with no CNI use was 113 micromol/L (95%, confidence interval [CI], 100.7 to 125.3 micromol/L) and in the rejectors or patients with CNI use (more than 7 days) was 154 micromol/L (95% CI, 135.0 to 173.0 micromol/L). In selected patients with rejection, analysis of circulating and intragraft lymphocytes revealed complete IL-2Ralpha saturation. CONCLUSIONS: This CNI avoidance study in immunologic low-risk patients, while only partially successful in preventing acute rejection, provided benefits to a sizable minority of patients who have not required chronic CNI therapy. However, wide acceptance of a CNI-sparing immunosuppression regimen may require a lower rate of acute rejection, possibly through the addition of a non-nephrotoxic dose of CNI. However, because complete IL-2Ralpha blockade was present during rejection, it can be assumed that alternative pathways, such as IL-15, may be responsible for the rejection; thus, the incorporation of non-nephrotoxic immunosuppressive agents, such as sirolimus, may provide a more strategic approach.

Early diagnosis of rejection of canine pancreas allografts by fine-needle aspiration biopsy.

In pancreatic allograft transplantation with bladder exocrine drainage, falls in urinary amylase (UA) levels have been shown to be an earlier marker of rejection than rises in fasting blood glucose levels. Nevertheless, this is often too late for reversal of the rejection process. In an attempt to diagnose rejection earlier, fine-needle aspiration biopsy was correlated with UA and graft histology. Sixteen dogs were given total pancreatic allografts, 10 without immunosuppression and 6 with triple therapy. FNAB and needle-core biopsies were performed on days 0, 2, 4, 7, 9, 24, and 30 and/or at functional rejection, defined as a fasting UA level of less than 5000 IU/L. Cytocentrifuge preparations of the FNABs were evaluated by total corrected increment (TCI) scores. These increased significantly from 1.0 (+/- 0.4; mean +/- SEM) 6 days, to 3.0 (+/- 1.2) 4 days before functional rejection. The increase was due to the presence of blast cells and macrophages. The TCI of healthy immunosuppressed grafts remained below 1.6 for 30 days after transplantation and was greater than 5.0 when pancreatitis or acute rejection was seen on conventional histology. Minimal histologic change had significantly lower TCI scores than both acute rejection (P less than 0.01) and pancreatitis (P less than 0.001). Acute rejection and pancreatitis were distinguished by a significant difference in increments of monocytes/lymphocytes and macrophages. In contrast to FNAB, UA levels did not differentiate minimal change from acute rejection but were a reliable marker of end-stage rejection.