Hepatitis C virus antibody status and survival after renal transplantation: meta-analysis of observational studies

The natural history of hepatitis C virus (HCV) among patients after renal transplantation (RT) remains incompletely defined. We conducted a systematic review of the published medical literature on the impact of hepatitis C antibody status on survival of patients who received RT. We used the random effects model of DerSimonian and Laird to generate a summary estimate of the relative risk (RR) for mortality and graft loss with HCV seropositivity across the published studies. We identified eight clinical trials (6365 unique patients); six (75%) were cohort studies and two (2/8 = 25%) controlled trials, respectively. Pooling of study results demonstrated that presence of anti-HCV antibody was an independent and significant risk factor for death and graft failure after RT; the summary estimate for RR was 1.79 (95% CI, 1.57-2.03; homogeneity test, p = 0.0427) and 1.56 (95% CI, 1.35-1.80; homogeneity test, p = 0.0192), respectively. As a cause of death, hepatocellular carcinoma (HCC) and liver cirrhosis were significantly more frequent among anti-HCV positive than anti-HCV negative RT patients. This meta-analysis demonstrates that RT recipients with anti-HCV antibody have an increased risk of mortality and graft failure compared with HCV antibody negative patients.

Multivariate Analysis of the Effectiveness of Using Antibody Induction Therapy According to the Degree of HLA Mismatches

OBJECTIVE

HLA mismatches have a strong impact on acute rejection and renal allograft survival. The objective of this study was to evaluate the effectiveness of antibody induction according to the degree of HLA mismatches.

METHODS

Of 20,429 deceased donor (DD) transplantations and 12,859 living donor (LD) transplantations reported to the United Network for Organ Sharing (UNOS) between 1999 and 2001, 51% of DD and 45% of LD transplant recipients received induction therapy. Propensity scores (PS) were calculated to indicate independent factors associated with the use of induction. Levels of HLA match examined for DD transplant recipients were 0 ABDR (n = 3239), 0 DR (n = 4210), and DR mismatched transplants (n = 12,980), and 0 (n = 1133), 1 (n = 3836), and 2 (n = 7890) haplotype mismatches for LD transplant recipients. Outcome parameters were reported as hazard ratios (HR) for graft loss and odds ratios (OR) for first-year acute rejection.

RESULTS

Recipients with HLA mismatches were more likely to receive induction antibody for DR mismatch in DDs (PS = 1.11, 95% confidence interval [CI] 1.04-1.19) and for haplotype mismatch in LDs (PS = 1.36, 95% CI 1.22-1.52). Induction reduced the likelihood of acute rejection for DD transplant recipients regardless of the level of HLA mismatch (OR = 0.70; 95% CI 0.57-0.85 in 0 ABDR MM; OR = 0.76, 95% CI 0.64-0.89 in 0 DR MM; and OR = 0.69, 95% CI 0.62-0.77 in DR MM), and for 2 haplotype mismatched LD transplant recipients (OR = 0.82, 95% CI 0.70-0.96); in other LD transplant recipients, reductions in acute rejection rates were observed but not statistically significant. Induction reduced the risk of graft loss for DR mismatched DD transplant recipients by about 12% (HR = 0.88; 95% CI 0.80-0.97).

CONCLUSIONS

Antibody induction resulted in a significant reduction of acute rejection and graft loss for patients with HLA mismatch.

Cellular immune responses to cytomegalovirus in renal transplant recipients

Control of CMV replication depends primarily on anti-CMV T lymphocyte activity. However, the functional T-cell responses to CMV in immunosuppressed solid organ transplant recipients are not well understood. In this study we employed cytokine flowcytometry (CFC) using pooled CMV peptides and viral lysates to detect CMV-specific T-cell responses in 17 healthy controls, 33 stable renal transplant recipients (Tx recipients) and 6 transplant recipients with active CMV infection (CMV(+)). We found that pooled peptides and lysates provide optimal detection of IFN gamma production in anti-CMV CD8(+) and CD4(+) T cells, respectively. In both healthy controls and Tx recipients, CMV-specific T-cell levels strongly correlated with serostatus. Seropositive Tx recipients have significantly higher levels of CMV-specific CD8(+) T-cell responses compared to healthy controls, which may signify an effort to control enhanced viral replication in immunosuppressed Tx recipients. In some individuals, absence of anti-CMV T-cell response may correlate with lack of viral clearance by ganciclovir therapy, even when CMV isolates are not ganciclovir resistant. Thus, monitoring cellular immunity with CFC along with viral load by PCR merits further exploration for identification of patients at the risk of developing CMV disease, tailoring prophylactic and therapeutic decisions and preventing complications.

Application of diagnostic classification algorithms to identify the most common causes of post-transplant complications

ICD-9-CM diagnoses for hospitalizations occurring during the first 6 post-transplant months were summarized into Clinical Classifications System (CCS) categories. Of the 28,900 patients examined, 54% had at least one hospitalization. There were 2.39 hospitalizations per patient-year at risk. The total Medicare inpatient costs were $339 million and mean length of stay was 8.3 days. The most common and costly CCS diagnosis was complications of a kidney transplant followed by infections, circulatory system disease, gastrointestinal disease and endocrine complications. The CCS is a useful tool to summarize the complexity of claims information in the USRDS and could prove useful in further claims research.

Alemtuzumab induction in kidney transplantation

The use of alemtuzumab for induction therapy is increasing. 7.6% of antibody induction recipients in 2003 and 9.3% of induction recipients in 2004 received alemtuzumab. Antibody induction, especially T-cell depleting agents, Thymoglobulin and alemtuzumab are very effective in preventing early acute rejection in the initial hospitalization for both deceased and living donor transplants. However, when examining the effect of antibody induction on acute rejection after the initial hospitalization during the first year, alemtuzumab induction was associated with increased odds of acute rejection in deceased donor transplants compared to no antibody induction, IL-2RA, and Thymoglobulin. There was no difference in acute rejection during the first year after initial hospitalization in living donor transplants among all 4 induction groups. Despite lower acute rejection rates with alemtuzumab induction, no difference in graft survival was observed compared to no antibody induction, IL-2RA, and Thymoglobulin over 24 months. We conclude that alemtuzumab is an effective induction agent in kidney transplantation. However, further studies are needed to assess its long-term efficacy and to establish the optimal immunosuppressive regimen that should be maintained when alemtuzumab is used as an induction agent.

Meta-analysis: Effect of hepatitis C virus infection on mortality in dialysis

BACKGROUND

The natural history of hepatitis C virus infection among patients on long-term dialysis treatment remains incompletely understood. Efforts to elucidate the natural history of hepatitis C virus in this population are difficult because of the slowly progressive nature of hepatitis C virus with often an unrecognized onset in patients whose life-expectancy is substantially diminished by end-stage renal disease.

AIM

To conduct a systematic review of the published medical literature concerning the impact of hepatitis C virus infection on the survival of patients receiving chronic dialysis. The relative risk of mortality was regarded as the most reliable outcome end-point.

METHODS

We used the random effects model of DerSimonian and Laird to generate a summary estimate of the relative risk for mortality with hepatitis C virus across the published studies.

RESULTS

We identified four clinical trials (2341 unique patients); three (75%) of them were prospective, cohort studies; the fourth was a case-control study. Pooling of study results demonstrated that presence of antihepatitis C virus antibody was an independent and significant risk factor for death in patients on maintenance dialysis. The summary estimate for relative risk was 1.57 with a 95% confidence interval (CI) of 1.33-1.86. A test for homogeneity of the relative risks across the four studies gave a P-value of 0.77. As a cause of death, hepatocellular carcinoma and liver cirrhosis were significantly more frequent among antihepatitis C virus-positive than -negative dialysis patients.

CONCLUSIONS

This meta-analysis demonstrates that antihepatitis C virus-positive patients on dialysis have an increased risk of mortality compared with hepatitis C virus-negative patients. The excess risk of death in hepatitis C virus-positive patients may be at least partially attributed to chronic liver disease with its attendant complications. Clinical trials with extended follow-up are currently under way to assess the effect of hepatitis C virus treatment on the excess risk of mortality in this population.

Meta-analysis: the effect of age on immunological response to hepatitis B vaccine in end-stage renal disease

BACKGROUND

Patients on maintenance dialysis typically show a suboptimal immune response to hepatitis B virus vaccine compared with the non-uraemic population. A variety of inherited or acquired factors have been implicated in this diminished response. Age-associated changes in immune status may contribute to decreased vaccine efficacy in older individuals although contradictory results have been reported in individuals with normal kidney function.

AIMS

To evaluate the relationship between age and immune response to hepatitis B vaccine in patients with end-stage renal disease by performing a systematic review of the literature with a meta-analysis of clinical trials.

METHOD

We used the random effects model of DerSimonian and Laird; sources of heterogeneity in effect estimates were explored by performing sensitivity analyses.

RESULTS

We identified 17 clinical trials (1800 unique patients); six (35%) were controlled studies. Pooling of study results demonstrated a significantly decreased risk of response to hepatitis B vaccine among older dialysis patients (overall risk ratio: 0.74; 95% confidence intervals: 0.70-0.79). The P-value was 0.0139 for our test of study heterogeneity. A lowered risk of response to hepatitis B vaccine persisted after exclusion of trials based on plasma-derived vaccines; it was present even when 'older' individuals were defined as being as 50 years (RR: 0.85, 95% CI: 0.75-0.96) or more (cut-off 60 years RR: 0.75; 95% CI: 0.66-0.85). An effect of age on seroprotection rate was present in all clinical reports, irrespective of the geographic origin of the study group: Europe (RR: 0.76; 95% CI: 0.70-0.83) North America (RR: 0.67; 95% CI: 0.60-0.74) or other countries (RR: 0.83; 95% CI: 0.71-0.97). Additional doses of vaccine did not appear to have an impact on RR of response by age.

CONCLUSIONS

Our meta-analysis showed a clear association between older age and impaired response to hepatitis B virus vaccine in end-stage renal disease patients. Such a relationship is biologically plausible. Vaccination schedules with adapted vaccine doses and frequent serum testing for loss of immunity against hepatitis B virus are recommended in elderly patients on maintenance dialysis.

Epidemiology and clinical significance of hepatotropic infections in dialysis patients. Recent evidence

Hepatitis C virus (HCV) infection is frequent among patients receiving long-term dialysis in developed and developing countries. It is difficult to assess the natural history of HCV in the dialysis population; however, recent studies have demonstrated that positive anti-HCV status is a significant and independent risk factor for mortality among dialysis patients. Recent meta-analyses have shown that interferon (IFN) initial monotherapy is effective in the treatment of chronic hepatitis C among dialysis patients, but tolerance to IFN mono-therapy was rather poor. Large, multicenter and prospective trials based on pegylated IFN for the treatment of chronic hepatitis C are planned. The frequency of HBV infection in patients undergoing maintenance dialysis in the industrialized world is low but not negligible; persistent HBsAg seropositivity is much higher in less-developed countries. Recent surveys have shown that detectable HBsAg/ HBV DNA status in serum is an independent and significant predictive factor for hepatocellular dysfunction in dialysis patients. No significant difference in morbidity and mortality between dialysis patients according to hepatitis B surface antigen status has been consistently shown. Preliminary reports suggest that lamivudine appears to be safe and effective in patients receiving long-term dialysis.

Treatment of chronic viral hepatitis in patients with renal disease

In the last several years, numerous studies on the natural history and outcomes of viral hepatitis in dialysis and transplantation have been reported. Despite these, the management of hepatitis C virus or hepatitis B virus-related liver disease in end-stage renal disease continues to be an area of controversy. This article aims to address the current therapeutic options for patients with renal disease and chronic viral hepatitis.

Lamivudine for the treatment of hepatitis B virus-related liver disease after renal transplantation: meta-analysis of clinical trials

BACKGROUND

Numerous reports have appeared on lamivudine use for the treatment of hepatitis B virus (HBV) infection after renal transplantation (RT). However, the efficacy and safety of lamivudine after RT remain unclear.

METHODS

The authors evaluated the efficacy and safety of initial lamivudine monotherapy in RT recipients with hepatitis B by performing a systematic review of the literature with a meta-analysis of clinical trials. The primary outcomes were hepatitis B (HB) e antigen (Ag) and HBV-DNA clearance (as measures of efficacy); the secondary outcomes were biochemical response (as measures of efficacy), dropout rate, and lamivudine resistance (as measures of tolerability). The authors used the random effects model of DerSimonian and Laird, and outcomes were analyzed on an intent-to-treat basis.

RESULTS

The authors identified 14 clinical trials (184 patients); all of these were prospective cohort studies. The mean overall estimate for HBV-DNA and HBeAg clearance, alanine aminotransferase normalization, and lamivudine resistance was 91% (95% confidence interval [CI], 86%-96%), 27% (95% CI, 16%-39%), 81% (95% CI, 70%-92%), and 18% (95% CI, 10%-37%), respectively. HBeAg seroconversion rate was assessed in four (28%) trials and ranged between 0% and 46%. The P value was greater than 0.05 for our test of study homogeneity. There was no association between rate of patients who were male patients or had cirrhosis, race, age, lamivudine dose, and HBV-DNA or HBeAg clearance. Increased duration of lamivudine therapy was positively associated with frequency of HBeAg loss (r =0.51, P =0.039) and lamivudine resistance (r =0.620, P =0.019). Only 2 (14%) of 14 studies reported a dropout rate greater than 0%.

CONCLUSIONS

Our meta-analysis showed that the majority of RT recipients with hepatitis B had high virologic and biochemical response with lamivudine. Tolerance to lamivudine was good. However, lamivudine resistance was frequent with prolonged therapy, potentially limiting its long-term efficacy after RT.

HBV infection in patients with end-stage renal disease

Controlling the spread of hepatitis B virus (HBV) infection in dialysis units has been one of major triumphs in the management of end-stage renal disease. However, HBV incidence and prevalence rates remain high in dialysis patients in less-developed countries, and HBV within dialysis units continues to spread in the industrialized world. Overall response rates to HBV vaccination are lower in dialysis patients than in the nondialysis population. Lamivudine is effective in the treatment of HBV infection in the dialysis setting. Presence of hepatitis B surface antigen (HbsAg) has a negative impact on patient survival after renal transplantation. Several issues remain unanswered with regard to the management of HBV infection in dialysis patients, including the management of lamivudine resistance and the optimal timing and duration of antiviral therapy. Liver biopsy prior to renal transplantation is crucial in order to identify and exclude patients with advanced fibrosis or even cirrhosis.

Meta-analysis: interferon for the treatment of chronic hepatitis C in dialysis patients

BACKGROUND

The efficacy of interferon monotherapy in dialysis patients with chronic hepatitis C remains unclear, although a number of small clinical trials have been published addressing this issue.

METHODS AND AIMS

We evaluated the efficacy and safety of initial interferon monotherapy in dialysis patients with chronic hepatitis C by performing a systematic review of the literature with a meta-analysis of clinical trials. The primary outcome was sustained virological response (as a measure of efficacy); the secondary outcome was drop-out rate (as a measure of tolerability). We used the random effects model of Der Simonian and Laird, with heterogeneity and sensitivity analyses.

RESULTS

We have identified 14 clinical trials (269 unique patients); two were controlled studies. The mean overall estimate for sustained virological response (SVR) and drop-out rate was 37%[95% confidence interval (CI) 28-48] and 17% (95% CI 10-28), respectively. The most frequent side-effects requiring interruption of treatment were flu-like symptoms (17%), neurological (21%) and gastrointestinal (18%). The overall weighted estimate for SVR in patients with hepatitis C virus genotype 1 was 30.6% (95% CI 20.9-48). In the sub-group of clinical trials (n = 5) with standard interferon administration (3 million units [MUI] thrice weekly, subcutaneous route, 24-week treatment), the overall mean estimate of SVR was 39% (95% CI 25-56). The studies were heterogeneous with regard to SVR and drop-out rate.

CONCLUSIONS

Tolerance to initial interferon monotherapy was lower in dialysis than nonuremic patients with chronic hepatitis C. However, more than one-third of haemodialysis patients with chronic hepatitis C have been successfully treated with interferon. Longer duration of interferon monotherapy does not appear to have a beneficial effect on the response rate. Further studies are warranted to define the optimal anti-viral regimen for chronic hepatitis C in dialysis population.

Controlling treatment allocation bias in a registry analysis when comparing calcineurin inhibitors

Previous analyses of outcomes between immunosuppressive regimens included data from the early years of tacrolimus use and frequently included all Tacrolimus- or cyclosporine-based regimens. We now evaluate clinical outcomes associated with only the two most commonly prescribed regimens--Tacrolimus (Tac)-mycophenylate mofetil (MMF) and cyclosporine (CsA)-MMF--using recent data reported to the UNOS Scientific Renal Transplant Registry. Data from living donor kidney transplants was chosen to minimize selection bias between treatment groups. Outcomes are reported only for recent years (1998 to 1999 with 3-year follow-up) because acute rejection rates were markedly higher in 1995 to 1997 compared to 1998 to 2000 (38% to 68% vs 21% to 32%) and clinical practice has evolved since 1995, which would have biased results in favor of more recent immunosuppressive regimens. Three-year graft survival for patients transplanted from 1998 to 1999 was significantly higher in living donor kidney transplant patients receiving CsA-MMF (91.1%, n = 4686) versus Tac-MMF (88.1%, n = 2393) (P =.0006). After adjustment for potential confounding variables, risk of graft failure at 3 years was significantly higher in patients receiving Tac-MMF versus CsA-MMF for both all-cause graft failure (hazard ratio 1.28, 95%CI 1.09 to 1.49, P =.002) and death-censored graft failure (hazard ratio 1.25, 95%CI 1.05 to 1.49, P =.013). In view of the reduced rejection rate that has been reported using Tac-MMF versus CsA-MMF in clinical trials, it is possible that the nonimmunologic effects of calcineurin inhibitors may now play an increasingly important role in determining graft survival rates. In conclusion, this large-scale registry analysis demonstrates that graft survival in living donor kidney transplant patients is significantly improved using CsA-MMF compared to Tac-MMF.

Patterns of administration of antibody induction therapy and their associated outcomes

1. There was a dramatic shift in the type of induction therapy used between 1996-2000. In 2000, more than half of recipients received induction therapy. 2. The type of transplants strongly influenced the use of antibody induction. LD recipients were least likely to receive antibody induction followed by unsensitized, sensitized cadaveric and SPK recipients. 3. Pan-T antibody induction was used more frequently in patients with DGF and in high immunologic risk groups. 4. IL-2 receptor antagonists have become the dominant induction therapy; even for recipients with high immunologic risk or those with DGF. 5. We cannot demonstrate the effects of pan-T antibody induction on the resolution of DGF. Pan-T antibody induction did not improve graft survival in any cohorts, although it was associated with lower acute rejection rates in LD and unsensitized groups. 6. IL-2R antibody induction therapy was associated with lower acute rejection and graft failure at one year in LD and unsensitized groups. However, this trend cannot be demonstrated in higher immunologic risk groups ie., sensitized cadaveric and SPK.

Report of the American Society of Transplantation conference on immunosuppressive drugs and the use of generic immunosuppressants

Considerable economic and health-related costs are associated with the life-long maintenance immunosuppressive therapy required to prevent transplant rejection. Generic medications have the potential of providing equivalent therapeutic efficacy at a lower economic cost. In 2001, the American Society of Transplantation invited experts to review the data and issues associated with the approval and use of generic immunosuppressants. A summary of that meeting is reported here. The generic medication approval process has been in effect for more than 30 years. All marketed generic cyclosporin formulations have met FDA criteria demonstrating bioequivalence in healthy subjects, and some were also tested in transplant recipients. Most participants agreed that generic narrow therapeutic index immunosuppressive agents provide adequate de novo immunosuppression in low-risk transplant recipients. However, some participants expressed concern regarding the currently unquantified risk that may be associated with switching immunosuppressive agents under uncontrolled circumstances. There was broad agreement among the participants that generic medications should be clearly labeled and distinguishable from innovator drugs, and that patients should be educated to inform their physicians of any switch to or among generic alternatives. There was also strong support in favor of requiring studies to demonstrate bioequivalence in potentially at-risk patient populations, specifically African-Americans and pediatric patients.

Transplantation of kidneys from HCV-positive donors: a safe strategy?

Hepatitis C Virus (HCV) infection is the most important cause of liver disease after renal transplantation (RT). The impact of HCV on patient and graft survival after RT remains controversial; however, the great majority of studies with large size and adequate follow-up have shown the detrimental impact of HCV on long-term patient and graft survival after RT. The use of kidneys from anti-HCV positive donors could help decrease the continuing disparity between the number of patients on the transplant waiting list and the number of patients receiving a transplant each year. Single-center experiences have suggested transplanting kidneys from anti-HCV positive donors only in anti-HCV positive dialysis patients. Such practice has not demonstrated any adverse effect on the short-term patient survival; the waiting times for RT were shortened. A better alternative seems to be a policy of transplanting kidneys from anti-HCV positive donors only in HCV RNA positive recipients. This requires HCV RNA testing of all anti-HCV positive dialysis patients awaiting RT. Matching donors and recipients for HCV genotype has been suggested; however, the assessment of donor HCV genotype is currently hampered by time constraints. Recent evidence based on large data base demonstrated that RT recipients of HCV-positive donors are at independent increased risk of mortality; unadjusted 3-year patient survival was 85% versus 93% (P=0.01) in all recipients of donor HCV-positive and HCV-negative kidneys, respectively. This was observed in all recipient subgroups including elderly and HCV-positive recipients. In the near future, rapid nucleic acid testing (NAT) of donors and recipients will allow the assessment of the HCV viremic status in order to maximize organ use. With appropriate informed consent, use of a renal graft from an HCV positive donor may be offered to an HCV infected recipient. Additional studies are needed to clarify the link between donor HCV-positive kidneys and patient mortality.

Intravenous immune globulin treatment inhibits crossmatch positivity and allows for successful transplantation of incompatible organs in living-donor and cadaver recipients

BACKGROUND

Sensitization to human leukocyte antigens (HLA) is a significant barrier to transplantation. Currently, no proven therapy exists to improve access to transplantation for highly sensitized patients. Here, we report a novel approach using intravenous immune globulin to modulate anti-HLA antibody and improve the chances for successful transplantation.

PATIENTS AND METHODS

Forty-five highly HLA-sensitized patients presented as candidates for living-donor kidney transplantation (n=28), cadaveric kidney transplantation (n=15), or heart transplantation (n=2). All patients had a positive CDC crossmatch (CMX) with their donors. In living-donor recipients, intravenous immune globulin (IVIG) was added to the CMX evaluation to determine whether blocking antibodies present in IVIG could inhibit cytotoxicity. For those who showed in vitro inhibition with IVIG (n=26), IVIG was administered (usually as a single dose, 2 g/kg) and the CDC CMX was repeated against the prospective donor immediately after IVIG infusion. If negative, the patient underwent transplantation with their living-donor kidney within 24 to 72 hr. A similar but modified protocol was performed for cadaver donor candidates, all of whom were highly sensitized and had had CMX positivity with multiple donors, negating transplantation. Reductions in CMX positivity, posttransplantation serum creatinine level, number and severity of rejection episodes, and patient and graft survival rates were determined.

RESULTS

Forty-two patients underwent transplantation. IVIG treatment completely abrogated the donor-specific CMXs in 35 of 42 patients. In the remaining 7 patients, the CDC CMX was inhibited, but flow cytometry CMXs remained positive. A total of 13 (31%) of 42 recipients developed rejection episodes 3 to 49 days after transplantation. Three grafts (7%) were lost to rejection. Mean serum creatinine level at 24 months was 1.4+/-0.4 mg/dL. Patient and graft survival rates were 97.6% and 89.1%, respectively, at 24 months.

CONCLUSIONS

The in vitro IVIG CMX technique predicts the ability of IVIG to reduce anti-HLA antibody levels in highly sensitized patients. Subsequent in vivo IVIG treatment of responders eliminates the positive CDC CMX and allows for successful transplantation. Thus a positive CMX result is not necessarily a contraindication for transplantation and allows access to transplantation for patients for whom it was previously contraindicated.

Fabry disease in a renal allograft

Incidental findings of rare diseases in organ donors can be seen in allograft biopsies that may have profound implications for the recipient and for the donor and their family. Fabry disease is an X-linked recessive lipid storage disease with cardiovascular, renal and lenticular abnormalities. Phenotypic expression in female heterozygote carriers depends on lyonization. Minimal data exists on outcomes of transplanted kidneys from carriers of Fabry disease. We report a patient with ESRD secondary to focal sclerosis who received a HLA-identical transplant from her sister whose pretransplant donor work up was completely negative. Post-transplant, while pregnant, the recipient developed increasing proteinuria and was biopsied. The biopsy showed extensive myelin figures consistent with Fabry disease. Subsequent genetic, enzymatic and pedigree analysis confirmed the diagnosis in the recipient, the donor and the donor's son. Two years post-transplant the patient continues to have non-nephrotic range proteinuria with normal serum creatinine.

Analysis of the United Network for Organ Sharing database comparing renal allografts and patient survival in combined liver-kidney transplantation with the contralateral allografts in kidney alone or kidney-pancreas transplantation

BACKGROUND

Combined liver-kidney transplantation (LKT) is the accepted treatment for patients with liver failure and irreversible renal insufficiency. Controversy exists as to whether simultaneous LKT with organs from the same donor confers immunologic and graft survival benefit to the kidney allograft. This study compares the outcomes of simultaneous LKT with the contralateral kidneys used for kidney alone transplantation (KAT) or combined pancreas-kidney transplantation (PKT) to understand the factors that account for the differences in survival.

METHODS

From October 1987 to October 2001, LKTs with organs from 899 cadaver donors were reported to the United Network for Organ Sharing; 800 contralateral kidneys from these donors were used in 628 KAT and 172 PKT recipients. These 800 paired control patients were the basis of this analysis.

RESULTS

Graft and patient survival rates were lower among LKT recipients compared with KAT (P<0.001) and PKT recipients (P<0.001), because of a higher patient mortality rate during the first 3 months posttransplant. Among human leukocyte antigen-mismatched transplants, LKT recipients demonstrated the highest 1-year rejection-free survival rate (LKT 70%, KAT 61%, and PKT 57% ) (P=0.005 vs. KAT, P=0.005 vs. PKT). There was a lower incidence of renal graft loss resulting from chronic rejection among LKT recipients (LKT 2% vs. KAT 8% vs. PKT 6%, P<0.0001).

CONCLUSIONS

Patients undergoing LKT exhibit a higher rate of mortality during the first year posttransplant compared with patients undergoing KAT and KPT. Analysis of the data indicates an allograft-enhancing effect of liver transplantation on the renal allograft.

Graft survival following living-donor renal transplantation: a comparison of tacrolimus and cyclosporine microemulsion with mycophenolate mofetil and steroids

BACKGROUND

Registry databases offer the statistical power to analyze differences in graft survival rates that may not be detected in randomized clinical trials. This study analyses 2-year graft survival using tacrolimus (tac) or cyclosporine (CsA) with mycophenolate mofetil (MMF) and steroids.

METHODS

Data reported to the United Network for Organ Sharing Renal Transplant Registry for living-donor kidney patients receiving a transplant during 1998 to 1999 were included. The primary end point was graft survival after adjustment for confounding variables. A Cox model multivariate analysis was used to adjust for potential confounding factors.

RESULTS

Patients receiving CsA-MMF (n=4,686) and tac-MMF (n=2,393) were included. Unadjusted all-cause 2-year graft survival rate was significantly higher with CsA-MMF than tac-MMF (94.3% vs. 92.2%, P=0.0006). After adjustment for potential confounding factors, risk of graft failure at 2 years was significantly higher in patients receiving tac-MMF versus CsA-MMF for both all-cause graft failure (hazards ratio [HR] 1.28, 95% confidence interval [CI] 1.09-1.49, P=0.002) and death-censored graft failure (HR 1.25, 95% CI 1.05-1.49, P=0.013). Other independent risk factors for graft failure were recipient or donor age greater than 55 years, female sex, pretransplant blood transfusions, one or two haplotype mismatches compared with zero haplotype mismatch, and panel reactive antibody (PRA) greater than 30%.

CONCLUSIONS

Our findings demonstrate that 2-year renal allograft survival is significantly higher in living-donor recipients receiving CsA compared with tac as initial immunosuppression in combination with MMF.

Kinetics of hepatitis C virus load during hemodialysis: novel perspectives

Hepatitis C virus (HCV) infection remains frequent among dialysis patients. The relationship between viral load and liver disease progression is currently a matter of debate; however, low HCV viral load (HCV RNA) is a well established predictor of successful antiviral treatment. Dialysis patients have immune compromise due to uremia; in spite of this, HCV viral load is not high and does not increase over time. A number of studies support the notion that this dynamics of HCV viral load may be related to lowering of HCV RNA titers during the HD procedure. It has been suggested that the intradialytic reduction of HCV is membrane-dependent; polysulphone (PS) and hemophan membranes appear more effective. Various mechanisms have been mentioned to explain the reduction of HCV RNA during hemodialysis (HD): adsorption of HCV onto dialysis membrane, HCV escape into spent dialysate, destruction of HCV particles or increased interferon (IFN) activity. Several investigators have noted that, at the end of the HD procedure, a virological rebound of HCV viremia occurs. Some suggestions have been made to minimize the risk for HCV escape into spent dialysate. However, controversial evidence on these issues exists: the HCV RNA reduction during HD procedures has not been seen in some studies and the relationship between the intra-dialytic reduction of HCV RNA titers and dialysis membrane is not completely understood. It is evident that additional long-term longitudinal studies by serial viral load estimations are needed to better define the dynamics of HCV viral load in the dialysis population.

Dual kidneys from marginal adult donors as a source for cadaveric renal transplantation in the United States

The current organ shortage has led to the utilization of double kidney transplants from marginal adult donors, but outcomes data are limited. The United Network for Organ Sharing registry database was used to compare the outcomes of 403 dual adult kidney transplantations (DKT) and 11,033 single kidney transplantations (SKT) from 1997 to 2000. Graft and patient survival and the effect of multiple risk factors were evaluated. It was found that DKT patients were older, less sensitized, and received grafts from older, more mismatched donors with longer cold ischemia times. There was also a greater percentage of donors with a history of diabetes or hypertension and African-American recipients and donors in the DKT group. Graft survival was inferior in the DKT group, with a 7% lower graft survival rate at 1 yr. There was a higher incidence of primary nonfunction in the DKT group, although the incidence of delayed graft function, early rejection treatment, and graft thrombosis did not differ. Multivariate analysis was used to identify African-American recipient ethnicity and retransplant as risk factors for graft loss. Graft survival was comparable in DKT and SKT with donors over 55 yr of age. DKT resulted in inferior graft outcomes compared with SKT. When compared with SKT with donors over 55 yr of age, DKT resulted in similar graft outcomes. These otherwise discarded kidneys should be cautiously considered as a source of marginal donors.

Multivariate analyses of antibody induction therapies

1. Between 1997-2002 a 3-fold increase in induction therapy was attributed to surging use of Simulect, Zenapax and Thymoglobulin. 2. Induction therapy reduced the hazard ratio by 8% in deceased and 13% in living donor transplants and reduced the risk of rejection by 26% in deceased and 13% in living donor allografts. 3. Thymoglobulin was used more often in sensitized and retransplanted recipients and those with delayed graft function. Zenapax was used more often in pediatric recipients and those receiving MMF. Simulect was used more often in recipients not receiving MMF. 4. Simulect was associated with increased risk of rejection, perhaps due to a negative association with MMF maintenance immunosuppression. On the other hand, recipients not given MMF had a decreased hazard ratio with Simulect induction. 5. Induction reduced the risk of rejection in deceased donor allografts with delayed graft function, and sensitized and Black recipients. However a resultant impact on hazard ratio was not observed in these high-risk cohorts. 6. When considering HLA compatibility, induction reduced the hazard ratio only for DR-mismatched deceased donor allografts. Thymoglobulin induction increased the hazard ratio for zero-haplotype-mismatched living donor transplants.