The role of donor-specific HLA alloantibodies in liver transplantation.

The impact of donor-specific HLA alloantibodies (DSA) on short- and long-term liver transplant outcome is not clearly defined. While it is clear that not all levels of allosensitization produce overt clinical injury, and that liver allografts possess some degree of alloantibody resistance, alloantibody-mediated adverse consequences are increasingly being recognized. To better define the current state of this topic, we assembled experts to provide insights, explore controversies and develop recommendations for future research on the consequences of DSA in liver transplantation. This article summarizes the proceedings of this inaugural meeting. Several insights emerged. Acute antibody-mediated rejection (AMR), although rarely diagnosed, is increasingly understood to overlap with T cell-mediated rejection. Isolated liver allograft recipients are at increased risk of early allograft immunologic injury when preformed DSA are high titer and persist posttransplantation. Persons who undergo simultaneous liver-kidney transplantation are at risk of renal AMR when Class II DSA persist posttransplantation. Other under-appreciated DSA associations include ductopenia and fibrosis, plasma cell hepatitis, biliary strictures and accelerated fibrosis associated with recurrent liver disease. Standardized DSA testing and diagnostic criteria for both acute and chronic AMR are needed to distil existing associations into etiological processes in order to develop responsive therapeutic strategies.

Eculizumab for the treatment of de novo thrombotic microangiopathy post simultaneous pancreas-kidney transplantation--a case report.

A 34-year-old female recipient of a simultaneous pancreas-kidney transplant presented 7 days posttransplant with acute renal allograft dysfunction, thrombocytopenia, and microangiopathic hemolytic anemia. Renal biopsy revealed acute antibody-mediated rejection (AMR) and acute thrombotic microangiopathy (TMA). Clinical and laboratory manifestations, which had only partly responded to treatment with daily plasma exchange and intravenous immunoglobulin, resolved rapidly and completely to eculizumab (Soliris, Alexion Pharmaceuticals, Inc., Cheshire, Conn), a complement factor C5 antibody. De novo posttransplant TMA is a rare and serious complication that can lead to graft loss in up to one third of cases. This is the first report of successful treatment of de novo TMA with eculizumab, which has previously shown benefit in recurrent atypical hemolytic uremic syndrome as well as in refractory acute AMR. Targeted complement inhibition offers the promise of a safe and effective therapeutic strategy in de novo TMA, especially in light of recent evidence suggesting that genetic mutations in complement regulatory proteins may predispose transplant recipients to this serious disease.

Living donor kidney transplant recipients and clinical trials: participation profiles and impact on post-transplant care.

Many transplant physicians believe that transplant candidates who enroll in clinical trials may have better outcomes than those who do not enroll. We examined a 7-year cohort (1997-2003) of adult primary, non-HLA identical, living donor kidney transplant (LDKT) recipients to determine whether demographic characteristics predisposed to enrollment and whether participation affected posttransplant care intensity and/or allograft function. Overall, 146 of 512 (28.5%) LDKT recipients enrolled in clinical trials. LDKT recipients who were male and those who lived <100 miles from our transplant center were significantly more likely to participate. During the first post-transplant year, study patients (SPs) had more clinic visits (p < 0.0001) and more allograft biopsies (p = 0.024) compared to nonstudy patients (NSPs), but comparable numbers of hospital readmissions and allograft ultrasounds. SPs and NSPs did not differ in 1-year creatinine clearance, delta creatinine or rejection incidence. Overall graft and patient survival were comparable. We conclude that clinical trial participants were disproportionately male, had increased intensity of post-transplant care but comparable outcomes to nonparticipants.

Transplant glomerulopathy as a cause of late graft loss.

Several pathophysiological processes contribute to chronic kidney transplant rejection. Among the most distinctive is transplant glomerulopathy, characterized by widening of the subendothelial space with accumulation of flocculent material and duplication of the basement membrane. The current study assessed the course of graft loss in patients with and without this form of injury. Twenty-five patients with prominent transplant glomerulopathy were identified from biopsies performed at a single center during 4 years. These patients were compared with control patients with a similar degree of renal dysfunction in whom biopsies showed chronic rejection without transplant glomerulopathy. Patients with transplant glomerulopathy showed an increased rate of graft loss after biopsy. Biopsies were performed longer after transplantation in these patients, however, than in control patients with an equal degree of graft dysfunction. Graft survival from the time of transplantation was therefore not different between the two groups. Morphological studies showed that transplant glomerulopathy was not associated with increased severity of chronic vascular injury characterized by arterial and arteriolar intimal thickening or hyalinosis. These findings show that transplant glomerulopathy may develop late after transplantation and separately from chronic vascular rejection. The appearance of transplant glomerulopathy on a biopsy specimen is followed by accelerated graft loss.

The role of tacrolimus in adult kidney transplantation: a review.

The use of tacrolimus (FK506) in adult kidney-transplant recipients has been the subject of a number of single- and multi-center studies. This review article focuses on those studies in which tacrolimus was used either as rescue therapy in patients who developed refractory rejection on cyclosporine (CyA)-based regimens or as primary immunosuppression in adult renal-allograft recipients. Twenty-five prospective and retrospective studies conducted in the US, Japan and Europe, including single- and multi-center experiences, were identified in the medical literature. Of these studies, most show a 74-98% initial success rate for tacrolimus rescue therapy. Comparative studies reviewed herein demonstrate comparable patient- and graft-survival rates between tacrolimus- and CyA-treated patients. Many studies have shown that rejection episodes occur with similar or lower frequency among patients treated with tacrolimus than among those given CyA as primary immunosuppression. The major toxicities associated with tacrolimus are nephrotoxicity, neurotoxicity and diabetogenicity. Results from several studies have also demonstrated an association between these tacrolimus side effects and high whole-blood trough levels of tacrolimus. In many cases, a reduction in dosage can reverse these adverse effects. In summary, based on both single- and multi-center data, tacrolimus has been demonstrated to be efficacious when used for either primary immunosuppression or as rescue therapy for refractory acute rejection in adult renal-allograft recipients.

Acute renal allograft dysfunction secondary to suprarenal arterial stenosis: a case series and review of the literature.

Stenosis of vessels proximal to the renal artery is an unusual cause of allograft ischemia. We report four patients who had such 'suprarenal' arterial stenoses leading to graft dysfunction that was reversed with revascularization. We additionally review the existing literature on this entity, outline the etiologies of such stenoses, as well as discuss the surgical and non-surgical therapeutic options in patients with this uncommon cause of allograft dysfunction.

Renal transplantation in adults with autosomal recessive inheritance of hemolytic uremic syndrome.

When hemolytic uremic syndrome (HUS) is occasionally inherited in an autosomal recessive mode, this occurs mainly in infants and children. We describe four families in which two adult siblings were affected with HUS in each kindred. HUS first occurred between the ages of 19 to 36 years, and the intervals between the onset of HUS in each sibling pair ranged from 6 months to 6 years. None of the patients had a typical prodrome of bloody diarrhea, and one had a recurrence of HUS before transplantation. All eight patients developed renal failure requiring dialysis and transplantation, and seven patients received kidney transplants. Donor kidneys were from parents, siblings, and cadavers. The initial renal transplants were performed from 6 months to 6 years after the onset of the syndrome. HUS recurred in six of the seven patients 2 weeks to 6.5 years after transplantation regardless of the interval between the onset of HUS and transplantation, the origin of the allograft, or the use of cyclosporin A. The only marker for autosomal recessive HUS is the occurrence of the syndrome in a second sibling several months to many years after its occurrence in the proband. In patients with the autosomal recessive form of HUS, the risk for a recurrence in an allograft is high regardless of the source of the kidney.

Rescue therapy with mycophenolate mofetil. Mycophenolate Mofetil Renal Refractory Rejection Study Group.

In three international phase III trials, MMF has been demonstrated to reduce the frequency and severity of acute renal allograft rejection episodes. As a treatment for acute refractory renal allograft rejection, MMF is also now showing strong promise in phase I and phase II trials. The mechanism of MMF to selectively inhibit purine synthesis in T- and B-lymphocytes results in a number of pathways in which it can interfere with deleterious immune responses in solid-organ transplant patients: inhibiting T- and B-cell activation and proliferation, inhibiting the glycosylation of adhesion molecules, and inhibiting the production of antibodies and possibly cytokines. The result is a new drug that not only can be used to prevent acute rejection episodes but, in contrast to other drugs such as azathioprine, can also be used to treat refractory acute rejection episodes. MMF may also have additional long-term benefits in that it is less mutagenic or carcinogenic than azathioprine, and it appears to suppress allograft arteriosclerosis and chronic rejection (see accompanying articles in this issue). Our own experience with MMF leads us to conclude that MMF treatments will soon become a standard, valuable alternative therapy for acute refractory allograft rejection.

Histopathological concordance of paired renal allograft biopsy cores. Effect on the diagnosis and management of acute rejection.

To assess the effect of sampling error on renal allograft biopsies, we determined the concordance of diagnoses between 2 biopsy samples from the same renal allograft and the frequency with which 1 biopsy sample would underdiagnose or lead to the undertreatment of acute rejection. Two core samples from the same allograft biopsy procedure were labeled as core A and core B and presented to both unblinded and blinded pathologists, and each pathologist independently assigned an acute and a chronic rejection grade. A set of clinical data with pertinent prebiopsy information was combined with either the core A or core B histopathological diagnosis and presented to 3 transplant nephrologists who made treatment recommendations for each combination. Two cores were obtained in 79 allograft biopsies. Core pairs differed by > or = 1 grade of acute rejection in 30% and 50% of cases for unblinded and blinded pathologist readings, respectively. Moderate or severe acute rejection would have been missed with a 1 core in 9.5% of cases, increasing to 25.6% if only biopsy pairs containing at least 1 reading of moderate or severe acute rejection are included. Therapy would have failed to be increased with a single core in 7.5% of cases, increasing to 10.5% if only pairs containing at least one recommendation of an increase in therapy are included. The use of 2 cores of renal allograft tissue provides better diagnostic information and thereby leads to appropriate increases in antirejection therapy without increasing the complication rate of the procedure.

Immunopharmacodynamic studies of cyclosporine in patients awaiting renal transplantation.

The immunopharmacodynamics of cyclosporine were investigated in eight hemodialysis patients awaiting renal transplantation. Cyclosporine was administered orally (10 mg/kg) and intravenously (4 mg/kg), with both administrations separated by at least one week. Plasma samples were processed at 37 degrees C and analyzed for specific cyclosporine and its four major metabolites (AM1, AM1c, AM9, and AM4N) using high-performance liquid chromatography. In addition, the in vitro immunosuppressive activity of these serial plasma samples was estimated as a relative percentage inhibition of third party mitogenic lymphocyte proliferation stimulated with phytohemagglutinin. The relationships between concentration and effect of cyclosporine versus time were noted. These results suggest that unchanged cyclosporine concentrations in plasma correlate with mitogen-induced lymphocyte suppression yielding significant immunosuppressant activity of cyclosporine. Control studies with plasma from healthy volunteers spiked with cyclosporine in the concentration range of 0-10,000 ng/mL were developed. A sigmoidal Emax model was fitted to the effect versus plasma concentration data. The ratio of effect versus predicted effect were calculated for intravenous cyclosporine dosing. There was a good correlation between the observed and predicted inhibitory effect.

The effects of ketoconazole on the intestinal metabolism and bioavailability of cyclosporine.

The pharmacokinetics of cyclosporine were studied in the blood of five normal healthy volunteers (two men and three women) after each received oral and intravenous cyclosporine alone and with concomitant oral ketoconazole. Administration of ketoconazole caused a significant decrease in intravenous cyclosporine clearance (0.18 +/- 0.05 L/kg/hr versus 0.32 +/- 0.09 L/hr/kg) and a significant increase in cyclosporine oral bioavailability (56.4% +/- 11.7% versus 22.4% +/- 4.8%) compared with values before ketoconazole administration. Steady-state volume of distribution for intravenously administered cyclosporine was unchanged (1.26 +/- 0.44 L/kg versus 1.10 +/- 0.27 L/kg). Hepatic bioavailability (1 - hepatic extraction ratio) calculated for intravenous cyclosporine increased by 11% in the presence of ketoconazole (86.3% +/- 3.7% versus 75.2% +/- 6.6% without ketoconazole), which accounts for only one third of the observed increase in cyclosporine oral bioavailability. Because it is unlikely that ketoconazole had a significant effect on either cyclosporine absorption or hepatic blood flow, the increase in cyclosporine bioavailability observed in this study is most likely explained by inhibition of gastrointestinal cytochrome P450 enzymes.

Long-term outcome in kidney transplant patients with hepatitis C (HCV) infection.

To assess the prevalence and long-term impact of HCV on kidney transplant recipients, we assayed 716 pre-transplant sera using a first-generation ELISA. The anti-HCV positive sera were confirmed by a 6-antigen radioimmunoassay (RIA). Patients were followed up for 5 years. Graft survival, function, evidence of chemical hepatitis (AST > 2x normal), patient mortality and cause of death were evaluated. The prevalence of anti-HCV antibody was 10.3%. In the 638 patients who were followed up for 5 years, there were no differences in graft function, graft survival, overall mortality, or death from sepsis or liver disease. Peak AST levels were significantly higher in anti-HCV positive patients compared to anti-HCV negative patients. At 5 years, the AST levels remained significantly higher in the anti-HCV positive group, however, this was only 6 U/1 > normal. Liver biopsies performed 3 to 7 years post-transplant in 80% of anti-HCV positive patients with chemical hepatitis showed 12% CAH, 50% mild hepatitis and 38% normal histology. Six (9.7%) patients seroconverted from anti-HCV positive to anti-HCV negative 2 to 5 years post-transplant. The presence of anti-HCV does not appear to alter long-term patient or graft survival, and histologic evidence of severe chronic liver disease was rare in anti-HCV positive patients with chemical hepatitis. From these results, the presence of anti-HCV antibody should not preclude kidney transplantation.

Transjugular intrahepatic portosystemic shunts for refractory ascites: assessment of clinical and hormonal response and renal function.

Cirrhosis is frequently complicated by ascites that may become resistant to diuretic therapy. Transjugular intrahepatic portosystemic shunts (TIPS) represent a new treatment for this debilitating condition. The aim of this study was to ascertain the clinical efficacy of TIPS, as well as its impact on renal function and on hormonal parameters. Five inpatients with refractory ascites were studied prospectively before TIPS, and 3 and 14 days after TIPS. After TIPS, ascites completely resolved or was minimal in all patients. Diuretics were discontinued in three subjects and decreased by at least 50% in two. One patient developed liver failure after TIPS and required liver transplantation; the others remained stable after a mean follow-up of 14 months. Mean urinary sodium excretion increased from 2.1 +/- 0.6 mEq/24 hr before TIPS to 13.0 +/- 4.3 mEq/24 hr 14 days after TIPS. Mean serum creatinine and glomerular filtration rate also tended to improve during the study period. With the exception of the patient who developed liver failure, plasma aldosterone concentration decreased from a mean of 126.0 +/- 29.9 ng/dL to 22.8 +/- 6.8 ng/dL (P = .04), and plasma renin activity decreased from a mean of 9.0 +/- 3.0 micrograms/L/h to 0.9 +/- 0.1 microgram/L/h (P = .08). Additionally, 19 patients who underwent TIPS for refractory ascites outside of this protocol were followed prospectively for a mean of 282 days. Clinical improvement in ascites control was noted in 74%, and the mean dose of diuretics was decreased by more than 50%. Nonresponders more often had underlying renal disease. In conclusion, TIPS is an effective therapy for refractory ascites in most patients.(ABSTRACT TRUNCATED AT 250 WORDS)

The risk of transmission of hepatitis B from HBsAg(-), HBcAb(+), HBIgM(-) organ donors.

Liver allografts from HBcAb(+), IgM(-), HBsAg(-) donors can transmit HBV to uninfected recipients. We currently no longer accept these livers for transplantation while continuing to accept the kidneys. The purpose of this study is to determine the risk of donor-transmitted HBV infections from HBcAb(+), HBIgM(-), HBsAg(-) organ donors and determine if the risk of donor-transmitted HBV infections and their severity is dependent on the organ being transplanted. This study consists of a retrospective review of the posttransplant course of recipients of HBcAb(+), HBIgM(-), HBsAg(-) donors accepted at UCSF from 6/85 to 12/93. Transmitted HBV infection was defined as one in which the recipient changed from HBsAg(-) prior to transplantation to HBsAg(+) posttransplant, with no other source. There were 25 of 1190 donors who were HBcAb(+), HBIgM(-), HBsAg(-); 1/42 kidney, 3/6 liver, and 0/7 heart HBsAg(-) transplant recipients of organs from these donors became HBsAg(+) after transplantation. This difference in infection rate (liver vs. kidney and heart) is statistically significant. The clinical course of the liver recipients was also more severe. All of the patients who became infected were HBsAb(-) and HBcAb(-) prior to transplant. We conclude that (1) HBV can be transmitted from HBcAb(+), HBIgM(-), HBsAg(-) organ donors, (2) the rate of transmission is highest and severity of infection is worst in the liver recipients; and (3) we will continue to transplant kidneys from these donors, preferably into immunized recipients.

Pharmacokinetics of orally and intravenously administered cyclosporine in pre-kidney transplant patients.

The pharmacokinetics of cyclosporine (CSA) and four metabolites were evaluated in eight hemodialysis subjects awaiting renal transplantation to compare metabolic patterns with those observed in post-transplant patients and normal volunteers. Each subject received a single 4-mg/kg intravenous and a single 10-mg/kg oral dose separated by a 1-week washout period. Blood samples were collected before and at .5, 1, 1.5, 2, 2.5, 3, 4, 6, 8, 10, 12, 14, and 24 hours after CSA dosing. Cyclosporine blood, plasma, and metabolite (M17, M1, M18, M21) levels were determined by high-pressure liquid chromatography. Mean (+/- standard deviation) CSA blood clearance was .47 +/- .15 L/hour/kg, steady-state volume of distribution (Vss) was 1.9 +/- .5 L/kg, and mean residence time (MRT) was 4.4 +/- 1.8 hours after intravenous dosing. With plasma, mean clearance was .70 +/- .31 L/hour/kg, Vss was 2.4 +/- 1.2 L/kg, and MRT was 3.7 +/- 2.2 hours. Cyclosporine bioavailability (F) averaged 24 +/- 11 and 24 +/- 15%, using blood and plasma, respectively. Values for clearance and Vss were approximately 30 to 100% greater than comparable estimates in healthy volunteers, but F and MRT were not altered to this extent. These changes might be explained on the basis of decreased protein binding in uremic patients. The area under the curve ratio for M17 and M1 to CSA increased an average of 1.7- and 3.9-fold, respectively, after oral dosing compared with intravenous administration, indicating increased conversion during first-pass metabolism.

Cyclosporine-induced hemolytic uremic syndrome in a heart transplant recipient.

We report a case of hemolytic uremic syndrome associated with the use of cyclosporine in a heart transplant recipient. The patient manifested many classic signs and symptoms of hemolytic uremic syndrome, and a diagnosis was confirmed by kidney biopsy. Treatment with plasma exchange was effective in halting the hemolysis, but renal function failed to improve. Rechallenge with cyclosporine caused recurrence of microangiopathic hemolysis. Because of concerns regarding allograft rejection, an experimental immunosuppressive agent, RS-61443, was used that was effective in controlling rejection and was not associated with recurrence of hemolytic uremic syndrome.

Cytokine and T cell receptor gene expression at the site of allograft rejection.

Intragraft cytokine and T cell receptor gene expression was analyzed in rejecting renal allografts by polymerase chain reaction (PCR). Message for IL-1 beta, IL-6, and TNF-alpha was detected in nephrectomy tissue with pathological evidence of acute or chronic rejection. Similarly, mRNA for both IL-6 and TNF-alpha was present in renal biopsies from acute rejecting kidneys. IL-2R, IL-4, and IL-5 mRNA was present in both rejecting and rejected kidney allografts, indicating that these cytokines may play a role in ongoing renal allograft rejection. Conversely, IL-2, IL-7, and IFN-gamma message was detected infrequently. In order to address the diversity of T cells in rejecting kidneys, we have analyzed the clonality of the TcR present within the allograft tissue. Rearranged TcR genes were identified in all allografts examined (n = 16) indicating the presence of T cells bearing the alpha/beta TcR. We have determined that there is a heterogeneous infiltration of T cells in the rejected allograft with TcR representing x = 7.47 +/- 2.4 families rearranged in samples obtained from nephrectomies, whereas x = 5.33 +/- 0.58 families were detected in samples obtained from biopsy tissue. These data indicate that (1) cytokines are produced locally which may contribute to graft cell destruction, (2) the heterogeneity of intragraft T cells during kidney allograft rejection may exist because nonspecific lymphocytes have been recruited to the site by locally produced cytokines or because T cells are responding to multiple epitopes or multiple donor antigens. Detection of intragraft cytokines and TcR may prove useful in elucidating the mechanism of rejection and therefore lead to improved immunosuppression.

Effect of food on the pharmacokinetics of cyclosporine in healthy subjects following oral and intravenous administration.

The pharmacokinetics of cyclosporine were studied in healthy subjects following administration of cyclosporine both orally (10 mg kg-1) and intravenously (4 mg kg-1) without and with high fat meals. Both blood and plasma samples (separated at 37 degrees C) were analyzed for cyclosporine concentration. Blood and plasma clearances of cyclosporine were calculated to be 0.36 and 0.47 L hr-1 Kg-1, respectively, and volume of distribution at steady state was calculated to be 1.21 L Kg-1, when cyclosporine was administered without a high fat meal. Using plasma analysis, the oral bioavailability of cyclosporine was estimated to be 21 and 79%, when administered without and with a high fat meal, respectively. When cyclosporine was administered intravenously together with a high fat meal, both clearance and volume of distribution increased significantly. Blood and plasma clearances of cyclosporine were 0.44 and 0.70 L hr-1 Kg-1, respectively, when cyclosporine was administered along with a high fat meal. We conclude that food not only enhances the absorption of cyclosporine but also enhances its clearance and volume of distribution. The observed variability in clearance, bioavailability, and volume of distribution values for cyclosporine across various pharmacokinetic studies can be partially accounted by the type of food administered and the sampling matrix used for analysis.