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Microarray analysis is used to tackle transplant-related problems as diverse as diagnosing rejection, predicting graft loss, and determining who can safely be removed from immunosuppression. Highly accurate predictions seem to be the norm. Unfortunately, many of these studies are flawed, either through questionable experimental design or improper validation methods. In addition, results are often presented in a misleading manner which exaggerates their true worth. In this paper, we describe the most common and serious errors and misrepresentations.

available at http://www.ncbi.nlm.nih.gov/pubmed/26137963 Editorial Comment: The new kidney allocation system that was activated last year increases the opportunity for transplantation in those with the highest levels of antibody sensitization. Specifically those candidates with panel reactive antibody levels of 98% to 100% will have the greatest increase in opportunity. This system is predicated on tissue typing that assesses the HLA-A, B, DR and DQ loci. It has become apparent that other loci, notably the DP locus, are important targets for antibodies, especially in highly sensitized candidates. The new system shares well matched kidneys across broader geographic areas, so it is important that cross-match predictions are accurate. This system will ensure that the matched kidney is transplanted into the intended candidate. Reassigning a new recipient after a positive cross-match will lead to increased ischemic times and possible discard. The authors describe the importance of characterizing the DP locus. Overall 11% of positive cross-matches in a test cohort were positive only due to HLA-DP antibodies. In their experience 6% of HLA-A, B and DR zero mismatches had a positive cross-match due to HLA-DP directed antibodies. This article is a plea for universal reporting of more complete HLA antibody testing so that virtual cross-match prediction can be more accurate.

Mycophenolate mofetil (MMF) is widely and successfully used in immunosuppressive regimens for the prophylaxis of organ rejection following transplantation. Conventionally, it is administered at a fixed dose without serial measurements of plasma concentrations of mycophenolic acid (MPA), the active metabolite. Recently, there has been an increased interest in therapeutic drug monitoring (TDM) of MMF therapy to optimize the benefit/risk index of the drug. Predose trough samples of MPA are considered most convenient and economic, thereby allowing an increased use of TDM in the transplant setting. However, the added value of TDM for MMF therapy is still under debate.This paper reviews (based on a systematic PubMed and EMBASE search, 1995-June 2006) the current evidence of the usefulness and clinical relevance of MPA trough level monitoring during MMF therapy in solid organ transplantation.Based on data available in the public domain, the contribution of MPA trough level monitoring during MMF therapy in solid organ transplant recipients remains unproven. Available studies have limitations and report conflicting results. There is a lack of prospective randomized trials, particularly in pediatric renal transplant recipients and in cardiac and liver transplantation. While there is a suggestion that there may be a relationship between efficacy and MPA trough levels, the majority of studies showed no correlation between MPA plasma concentrations and adverse effects. Based on current evidence, the adherence to presently recommended target ranges for MPA troughs in solid organ transplantation cannot assure an improved clinical outcome with MMF therapy. Whether MPA trough level monitoring leads to improved efficacy and less toxicity is currently subject to a large randomized trial; final results are eagerly awaited.

Tobacco use adversely affects transplant outcomes such as graft survival, patient survival, and other conditions that alter transplant patient longevity. Especially concerning is tobacco's relationship to cardiovascular disease, the number 1 cause of death in kidney transplant recipients. Many authors conclude that tobacco interventions ought to be provided to patients and sometimes lament that there are no tobacco dependence interventions designed for kidney transplant recipients. European Best Practice Guidelines for Renal Transplantation also support tobacco dependence interventions. The purpose of this article is to describe one institution's experience in implementing the clinical practice guideline for treating tobacco use and dependence within a kidney and pancreas transplant program.

Cinacalcet, a calcimimetic, was evaluated in persistent hyperparathyroidism after kidney transplantation (Tx). Ten kidney transplant recipients and one kidney-pancreas recipient with persistent post-Tx hypercalcemia (serum calcium [SCa] > 10.2 mg/dl), stable graft function, and intact parathyroid hormone (iPTH) > or = 2 times normal received 30 mg/d cinacalcet between 2 mo and 5 yr after Tx. SCa, serum phosphorus (SP), and iPTH were measured before and after cinacalcet. Mean pre-cinacalcet SCa was 10.9 mg/dl (8.6 to 11.9 mg/dl). Average pre-cinacalcet SP was 2.9 mg/dl (1.8 to 4.0 mg/dl). Mean pre-cinacalcet iPTH was 267.0 pg/ml (99 to 723 pg/ml). After cinacalcet, SCa decreased on average by 1.6 mg/dl (95% confidence interval 1.2 to 2.1; P < 0.0001). Post-cinacalcet SP increased on average 0.45 mg/dl (P = 0.046). Post-cinacalcet iPTH averaged 156.9 mg/dl (P = 0.10). Graft function remained stable. Cinacalcet lowers SCa and raises SP in the short term in patients with persistent post-Tx hyperparathyroidism; long-term bone effects and persistent hyperparathyroidism merit further study.

BK virus nephropathy (BKVN) is now recognized as a major cause of renal allograft loss. Recent reports suggest that retransplantation in patients with graft loss due to BKVN is safe after return to dialysis. Since early transplantation is associated with improved outcomes, it would be advantageous if this procedure could be performed prior to ultimate graft loss. However, little data are available regarding the safety of this approach during active viremia. In this report, we describe successful preemptive retransplantation with simultaneous allograft nephrectomy in two patients with active BKVN and viremia at the time of surgery. With 21- and 12-month follow-up, respectively, both patients have stable allograft function and no evidence for active viral replication. We conclude that preemptive retransplantation can be considered in patients with failing allografts due to BKVN.

Mycophenolate mofetil (MMF) has been used in kidney and pancreas transplantation for almost 10 years. In the pivotal phase III trials, MMF use was accompanied by a dramatic reduction of rejection rates in kidney transplantation; however, the impact on graft and patient was undetermined. Analyses of the United States Renal Data System and the Scientific Registry of Transplant Recipients databases later provided a valuable measure of the impact of MMF in improving outcomes. In this review, we provide a synopsis of the prospective studies, including but not limited to the pivotal MMF approval trials, and analyses of the national transplant registries relevant to the long-term impact of MMF in kidney transplantation. Indeed, a substantial body of evidence has shown MMF treatment improves patient survival, graft survival, and death-censored graft survival in kidney transplantation. The beneficial effects of MMF have been particularly notable in high-risk recipients such as African Americans. In coming years, these benefits will require reevaluation in the context of the growing use of novel protocols combining MMF with tacrolimus or sirolimus.

Cyclosporine (CsA) nephrotoxicity is enhanced by sirolimus (SRL). Tacrolimus is perceived to be less nephrotoxic than CsA, and therefore, CsA has been largely replaced by tacrolimus (TAC) when calcineurin inhibitors are used with SRL. We analyzed 44 915 adult renal transplants in the Scientific Renal Transplant Registry (SRTR) from 2000 to 2004. Three thousand five hundred twenty-four (7.8%) patients received a baseline immunosuppressive regimen of TAC/SRL, with an inferior overall (log-rank p < 0.001) and death-censored graft survival (p < 0.001) as compared to TAC/MMF (N = 27 007). This effect was confirmed in multivariate Cox models; the adjusted hazard ratio (AHR) for overall graft loss with TAC/SRL was 1.47 (95% CI = 1.32, 1.63) and for CsA/SRL 1.38 (95% CI = 1.20, 1.59) relative to TAC/MMF. These effects were most apparent in high-risk transplants. Six-month acute rejection rates were low (11.5–12.6%) and not different between groups. In summary, national data indicate that TAC/SRL as compared to TAC/MMF is associated with significantly worse renal allograft survival in all subgroups of patients and, in particular, higher-risk transplants. These results have to be interpreted in the context of the inherent limitations of any retrospective database analysis and evaluated in context with data from prospective clinical trials.

Preservation techniques are crucial to deceased donor kidney transplantation (DDTx), but the efficacy of pulsatile perfusion (PP) versus cold storage (CS) remains uncertain. We describe patterns of PP use and explore four fundamental questions. What kidneys are selected for PP? How does PP affect utilization of donated kidneys? What effect does PP have on outcomes? When does PP appear to be most efficacious? We examined rates of PP in DDTx in the United States from 1994 to 2003. We generated models for organ utilization, delayed graft function (DGF) and for the use of PP. We analyzed the long-term effect of PP with multivariate Cox models. The utilization rates for non-expanded criteria donors (ECDs) were similar by storage type, but for ECDs there was a significantly higher utilization rate with PP (70% with PP vs. 59% with CS, p < 0.001). Use of PP was widely variable across transplant centers. DGF rates were significantly lower with PP (27.6% vs. 19.6%). PP was associated with a mild benefit on death censored graft survival (adjusted hazard ratio = 0.88, 95% CI 0.85-0.91). Reduced DGF and significantly lower discard rates of ECDs associated with PP suggest an important utility of PP in renal transplantation. Additional evidence of improvement in graft survival, particularly in more recent years, provides further encouraging evidence for the use of PP.

This paper presents the findings of an investigation of transit service integration practices in the United States. A review of industry literature identified the various types of service integration practices that have been and are being implemented, including infrastructure, schedule, fare payment, information, and special events and emergency conditions integration. In addition, the review revealed how the introduction of such practices is part of overall changes in transit properties’ way of conducting business. The research made use of a two-stage survey of transit agencies that have implemented specific practices. An initial survey cast a wide net to identify innovative practices by 96 agencies across the country. A subsequent survey targeted specific examples of each type of practice and addressed the objectives of the practices, agency responsible for promoting integration, effectiveness of the practices, measures of effectiveness, barriers faced by implementers, and lessons learned. While there has been little formal evaluation of these practices by transit agencies, the predominant view is that transit integration supports the overall goals of the transit agency and provides substantial benefits to customers. Data to support impact evaluation are limited; however, several case studies were performed to probe integration practices in more depth. Transit agencies that have implemented integration practices have been able to overcome barriers to coordination and integration and have made a number of trailblazing efforts.

Background Dendritic cells (DCs) are potent antigen-presenting cells that induce and regulate immune responses. Recent advances allow accurate quantification of peripheral blood (PB) myeloid and plasmacytoid DC populations (mDC and pDC, respectively), although the response to renal transplantation (RT) remains unknown. Methods Using flow cytometry, PBDC levels were quantified in patients with end-stage renal disease (ESRD) undergoing renal transplantation. Results PBDC levels were significantly reduced in ESRD patients pretransplantation compared to healthy controls, with further reduction noted immediately following a hemodialysis session. RT resulted in a dramatic decrease in both subsets, with a greater reduction of pDC levels. Both subset levels were significantly lower than in control patients undergoing abdominal surgery without RT. Subgroup analysis revealed significantly greater mDC reduction in RT recipients receiving antilymphocyte therapy, with preferential binding of antibody preparation to this subset. Samples from later time points revealed a gradual return of PBDC levels back to pretransplant values concurrent with overall reduction of immunosuppression. Finally, PBDC levels were significantly reduced in patients with BK virus nephropathy compared to recipients with stable graft function, despite lower overall immunosuppression. Conclusions Our findings suggest that PBDC levels may reflect the degree of immunosuppression in renal allograft recipients. Furthermore, PBDC monitoring may represent a novel strategy to predict important outcomes such as acute rejection, long-term graft loss, and infectious complications.

Cytomegalovirus (CMV) is an important pathogen often encountered after solid organ transplantation and is associated with increased morbidity and mortality. Resistance of CMV to antiviral agents is becoming more common but with few treatment strategies. Two specific mutations in the CMV genome--the UL97 and UL54 genes--correlate with antiviral drug resistance. We describe a 49-year-old, CMV-seronegative woman who received a CMV-seropositive donor kidney transplant and appropriate CMV prophylaxis. Approximately 1 month after transplantation, the patient developed CMV viremia that responded to valganciclovir. She was later diagnosed with recurrent CMV infection, CMV resistance, and both the UL97 and UL54 gene mutations. The patient responded to foscarnet and significant reduction of immunosuppression; she was negative for CMV viremia for the next 12 months. This case illustrates the importance of having heightened awareness for the possibility of panresistant CMV early and decreasing immunosuppression as the cornerstone of treatment.

Division of Nephrology, University of Arizona HealthSciences Center, Tucson, AZ Corresponding author: Titte R. Srinivas,srinivat@musc.eduReceived 31 May 2013, revised 12 June 2013 andaccepted for publication 04 July 2013Acute rejection in the transplanted kidney is diagnosedin the clinic using a combination of renal dysfunction,renal biopsy and alloantibody levels (1). Despite itsinvasive nature and high interobserver variability, therenal biopsy remains the gold standard for the diagnosisof acute rejection (2). Because of these limitations of therenal biopsy, the goal of discovering accurate andreproducible biomarkers in the urine and blood amongkidney transplant recipients has been an important line ofresearch (3–5).InthisissueofAJT,Hriciketal(6)reportonthefindingsofamulticenter observational study conducted under the aegisof the NIH-sponsored Collaborative Trials in Organ Trans-plantation study consortium (CTOT). In the CTOT-01 study,Hricik et al discovered that low urinary CXCL9 (a T cellchemoattractantinducedbyinterferongamma)at6monthsposttransplantationwasassociatedwithalowerprobabilityof development of acute rejection or a decline in renalallograft function over subsequent follow-up to 24 monthsin the 280 kidney transplant recipients studied (6). Theauthors concluded that low urinary CXCL9 protein could beused as a biomarker to identify transplant recipients at lowrisk for future immunologic events. The authors are to beapplaudedontheconductandreportingoftheirmulticenterprospective inquiry. However, the study raises severalquestions that bear reflection.The CTOT-01 study examined, serially, urinary mRNA ofseveral candidate cytokine and effector molecules as wellas proteins pertaining to, in the context of a 6-month perprotocol allograft biopsy, biopsies performed for cause andclinical follow-up.Using this approach, the positive predictive value (PPV) ofurinary CXCL9 protein for acute rejection was modest at67% whereas the negative predictive value (NPV) wasmuch higher at 92%. The performance of urinary CXCL9mRNAinthepredictionofacuterejectionwasinferior(PPV,61.5%; NPV, 83%). This discrepancy in urinary CXLC9proteinandmRNAwasattributedtothedifficultiesinusingurine as a matrix for mRNA samples. Further, the authorspropose that low urinary CXCL9 at Month 6 posttransplan-tation would allow the identification of subjects at low riskfor acute rejection or decline in GFR between 6 and24 months posttransplantation (NPV, 92.5–99.3%). TheCTOT-01studypopulationwasatlowimmunologicrisk;themean panel reactive antibody of the subjects was 12.9%.Most recipients received living donor transplants, mostreceived antibody induction and all flow crossmatches attransplantwerenegative.Notably,asreportedbyHriciketal(6),intheCTOT-1population,rejection(gradesuspiciousorhigher)wasreportedin25/170(13.8%)of6-monthprotocolbiopsies and in 43/79 (54.43%) of for-cause biopsies byMonth 6.These findings are an important contribution to thedevelopment of biomarkers in transplantation and certainlyare a welcome addition to all clinicians as a piece in thepuzzle of clinical decision making. However, the studyalso teaches us another important lesson. In the modernera of transplantation, 1-year acute rejection rates in low-immunologic risk patients should approach 10%. In thissetting, if one were to consider using a biomarker as asubstitute for the invasive renal biopsy, what is desirableis a test not only with a high NPV but also with a high PPV.The ideal test would help detect disease early in its clinicalcoursewithoutanexcessoffalsepositives.Inthiscase,themarker must have high sensitivity and specificity. As thebaseline event rate (acute rejection) is expected to be lowwithmodernimmunosuppressioninalow-riskpopulation,ahigh negative predictive value for rejection while indisput-ably of value does not answer what one may consider theeven more difficult question of who will develop disease(rejection/injury).Clinical decisions are in large part based on conditionalprobabilities given the known pretest probability (preva-lence) and the ability to distinguish when a test is either atrue positive or true negative. Given this one must invokeBayes theorem, simply stated mathematically as, PPV

To evaluate the association between a regimen of cyclosporine microemulsion (CsA) + sirolimus (Rapa) treatment versus CsA and mycophenolate mofetil (MMF) and renal allograft survival, we analyzed 23 016 primary recipients reported to the Scientific Registry of Transplant Recipients between January 1, 1998 and July 26, 2003. Univariate Kaplan-Meier analysis and multivariate Cox proportional hazard models correcting for demographic and clinical covariates were used to estimate the relative risks for CsA+Rapa versus CsA+MMF-treated patients reaching study endpoints. Subgroup analyses were conducted for recipient ethnicity and donor type. CsA+Rapa was associated with significantly lower graft survival (74.6% vs. 79.3% at 4 years, p = 0.002) and death-censored graft survival (83.7% vs. 87.2%, p = 0.003) compared to CsA+MMF. In multivariate analyses, CsA+Rapa was associated with a significantly increased risk for graft loss, death-censored graft loss and decline in renal function (HR = 1.22, p = 0.002; HR = 1.22, p = 0.018 and HR = 1.25, p < 0.001, respectively). Similar results were obtained in recipient ethnicity and donor type subgroups. In summary, CsA+Rapa was associated with significantly worse graft survival and death-censored graft survival compared to CsA+MMF, and likely reflects full-dose CsA +Rapa. Outcomes regarding alternative strategies of Rapa utilization with reduced CsA, with alternative agents or with no calcineurin inhibitor cannot be extrapolated from these data.

Acute rejection is known to have a strong impact on graft survival. Many studies suggest that very low acute rejection rates can be achieved with current immunosuppressive protocols. We wanted to investigate how acute rejection rates have evolved on a national level in the U.S. and how this has impacted graft survival in the most recent era of kidney transplantation. For this purpose, we analyzed data provided by the Scientific Registry of Transplant Recipients regarding all adult first renal transplants between 1995 and 2000. We noted a significant decrease in overall acute rejection rates during the first 6 months, during the first year, and also in late rejections during the second year after transplantation. Despite this decrease in the rate of acute rejection, there was no significant improvement in overall graft survival; furthermore, we noted a statistically significant trend towards worse death-censored graft survival. There was also a trend for a greater proportion of rejection episodes to fail to recover to previous baseline function after treatment. Our data suggest that decreasing acute rejection rates between 1995 and 2000 have not led to an increase in long-term graft survival. Part of this discordance might be related to a higher proportion of acute rejections which have not resolved with full functional recovery in more recent years. However, the etiology of this concerning trend for worse death censored graft survival in recent years will warrant further investigation.

Cyclosporine and tacrolimus share the same pharmacodynamic property of activated T-cell suppression via inhibition of calcineurin. The introduction of these drugs to the immunosuppressive repertoire of transplant management has greatly improved the outcomes in organ transplantation and constitutes arguably one of the major breakthroughs in modern medicine. To this date, calcineurin inhibitors are the mainstay of prevention of allograft rejection. The experience gained from the laboratory and clinical use of cyclosporine and tacrolimus has greatly advanced our knowledge about the nature of many aspects of immune response. However, the clinical practice still struggles with the shortcomings of these drugs: the significant inter- and intraindividual variability of their pharmacokinetics, the unpredictability of their pharmacodynamic effects, as well as complexity of interactions with other agents in transplant recipients. This article briefly reviews the pharmacological aspects of calcineurin antagonists as they relate to the mode of action and pharmacokinetics as well as drug interactions and monitoring.

A new study has identified a gene set that might predict the development of renal allograft fibrosis. This finding represents a leap forward in transplant diagnostics, but further studies are needed to demonstrate that interventions based on this gene set can prevent fibrosis before it can be utilized to inform therapeutic decisions.

Both medical care and pharmaceutical development have led to an increase in expected graft and patient survival for patients who undergo renal transplantation. From a research perspective, it has become increasingly difficult to study the efficacy of new therapies using traditional 'hard' endpoints. In reaction to this dilemma, the transplant community has sought a surrogate endpoint. A natural candidate for a surrogate marker for graft loss that has been proposed is renal function (serum creatinine or calculated GFR levels). Using data from the USRDS, we conducted a retrospective evaluation of transplant data from 1988 to 1999 to quantify the predictive value of renal function for the outcomes of graft loss, death-censored graft loss, and patient death. Renal function along with the change in renal function demonstrated a high relative risk for ultimate graft survival and graft loss (odds ratio = 2.2 for an increase of 1 mg/dL). However, the predictive value as measured by the area under the receiver operating characteristic curve (AUC) for this criteria was poor (0.627). These findings held true for the slope of creatinine and formulations of GFR. While renal function is a strong risk factor and highly correlated with graft failure, the utility of renal function as a predictive tool for graft loss is limited.

This review focuses on the use of mycophenolate mofetil (MMF) as an immunosuppressive agent in solid-organ transplantation. MMF, a non-competitive inhibitor of inosine monophosphate dehydrogenase, blocks de novo purine synthesis in T and B lymphocytes, resulting in the selective inhibition of proliferation of these cells in response to antigenic stimuli. MMF may also promote apoptosis of these cells. The immunosuppressive ability of MMF is thought to derive mainly from the inhibition of inosine monophosphate dehydrogenase. The other effects of MMF include suppression of antibody synthesis by B lymphocytes, inhibition of proliferation of smooth muscle cells in culture and impaired glycosylation of adhesion molecules. MMF may exhibit anti-inflammatory effects resulting from decreased activity of the inducible form of nitric oxide synthase, a consequence of depletion of tetrahydrobiopterin, which leads to decreased generation of peroxynitrite, a pro-inflammatory molecule. The pharmacokinetics, pharmacodynamics and principles underlying therapeutic drug monitoring of MMF are reviewed. The results of the pivotal clinical trials of MMF in kidney and heart transplantation are discussed and a summary of the major studies demonstrating a positive effect of MMF on renal transplantation outcomes is presented. The use of MMF in the context of ABO-incompatible renal transplantation, renal transplantation in highly sensitised and cross-match positive recipients, humoral rejection of renal allografts, chronic allograft nephropathy and steroid/calcineurin inhibitor minimisation in renal transplantation are also discussed.

Calcineurin inhibitors (CNI) are an important component of most immunosuppressive protocols utilized in renal transplantation. Both CNI available (cyclosporine and tacrolimus) have been used for many years. Studies comparing the efficacy of these two agents in terms of long-term graft or patient survival have thus far failed to show an advantage for either agent. This failure to show a difference could possibly be due to underpowering of clinical trials. The authors used the SRTR database to analyze 5-yr graft survival of the microemulsion formulation of cyclosporine (Neoral) as compared with tacrolimus. To minimize the donor variability and bias, a paired kidney analysis was used. Deceased donors from the years 1995-2002 were analyzed from the SRTR database. All paired kidneys during this period, where one kidney was allocated to a patient receiving initial Neoral therapy and its mate allocated to a patient receiving initial tacrolimus therapy were evaluated. Multivariate and univariate analysis were performed. Univariate analysis demonstrated equivalent graft survival for Neoral compared with tacrolimus (66.9% versus 65.9%, respectively). Multivariate analysis could not demonstrate a difference in risk for 5-yr patient survival or graft loss. Renal function was superior for tacrolimus at all time points, whereas the slope of 1/Cr over time did not differ for the two agents. In this paired kidney analysis, no difference in 5-yr renal allograft survival could be found between the two agents. Renal function was superior in the patients receiving initial tacrolimus therapy; however, slope of 1/Cr did not differ between the agents.

The discipline of renal transplantation has been fortunate in having one of the largest and most complete databases of any field of medical inquiry. Many analyses have been performed utilizing these databases and a wide array of views regarding the role and limitations of these analyses exists. In this manuscript, we hope to present the merits and limitations of large database analysis in renal transplantation. In addition, we will attempt to go over the major databases' structures and the critical issues of coding, verification and clinical awareness that help maintain the integrity of this type of analysis. Other fundamental issues that will be covered include the relationship of single center and randomized prospective studies with database analyses, statistical considerations, and hidden selection bias inherent in registry analysis. We hope to present both a guide to investigators who are first embarking on large-scale database analysis and also to present a fair view of the utility and limitations of a potentially very useful research tool in renal transplantation.

Background Chronic kidney disease is thought to be a potential risk factor for cardiovascular death. In renal-allograft recipients, cardiovascular disease is the most significant cause of death. The purpose of this study was to investigate if renal function has a significant role in determining the risk for cardiovascular death in renal-allograft recipients. Methods We analyzed 58,900 adult patients registered in the United States Renal Data System who received a primary renal transplant between 1988 and 1998 and who had at least 1 year of graft survival. The primary study endpoint was death from a cardiovascular event beyond 1 year of transplantation. Secondary endpoints were death caused by infections and malignancy-related deaths. Cox proportional-hazard models were used to estimate the effect of renal function on cardiovascular death, infectious death, and malignancy-related death while correcting for potential confounding variables, such as donor and recipient age, gender, race, cause of end-stage renal disease, length of dialysis before transplantation, year of transplantation, donor source and age, delayed graft function, and immunosuppressive regimen. Results Serum creatinine values at 1 year after transplantation were strongly associated with the risk for cardiovascular death. Above a serum creatinine value of 1.5 mg/dL, there was a significant and progressive increase in the risk for cardiovascular death. The risk of cardiovascular death was significantly higher when patients who lost allograft function were included in the analysis. There was an association between worsening renal function and infectious death, but there was no association between renal function and malignancy-related death. Conclusion Serum creatinine at 1 year is strongly associated with the incidence of cardiovascular death independent of known risk factors.

Background. To evaluate the association of long-term continuous mycophenolate mofetil (MMF) versus azathioprine (AZA) therapy and renal allograft function, as measured by the slope of reciprocal creatinine, we analyzed 49,666 primary renal allograft recipients reported to the United States Renal Data System between October 31, 1988 and June 30, 1998. Methods. The primary study endpoint was defined as a greater than 20% decrease below a 6-month baseline of 1/serum creatinine (SCr) (slope of reciprocal creatinine) at or beyond 1 year after transplantation. A secondary endpoint was defined as reaching an SCr value greater than 1.6 mg/dL. Univariate Kaplan-Meier analysis and multivariate Cox proportional hazard models were used to investigate the risk of reaching the study endpoints. Multivariate analyses were corrected for potential confounding covariates. Results. According to the Cox proportional hazard model, 12-month continued therapy of MMF versus AZA was associated with a protective effect against declining renal function, as measured by the slope of reciprocal creatinine (relative risk [RR]=0.84, confidence interval 0.78-0.91, P

To evaluate the association of long-term continuous (minimum 1 year) mycophenolate mofetil (MMF) vs. azathioprine (AZA) therapy with the incidence of late acute rejection, we analyzed 47 693 primary renal allograft recipients reported to the United States Renal Data System between 1988 and 1998. The primary study endpoint was acute rejection beyond 1 year after transplantation. Univariate Kaplan-Meier analysis and multivariate Cox proportional hazard models were used to investigate the risk of reaching the study endpoints. All multivariate analyses were corrected for potential confounding covariates. Mycophenolate mofetil was associated with a 65% decreased risk of developing late acute rejection as compared to AZA (RR = 0.35, CI 0.27-0.45, p < 0.001). The incidence of acute rejection episodes at 2 and 3 years post-transplantation was significantly lower in the MMF group (0.9% at 2 years, 1.1% at 3 years) than the AZA group (6.1% at 2 years, 9.3% at 3 years). In the primary vs. repeat late rejection analysis, MMF patients exhibited a decreased late acute rejection risk of 72% (RR = 0.28, p < 0.001) and 60%, respectively (RR = 0.40, p < 0.001). In African Americans, the late acute rejection risk was 70% lower in MMF patients than AZA patients (RR = 0.30, p < 0.001). Further study is indicated to determine the optimal duration of MMF therapy after renal allograft transplantation.

The number of people with end-stage renal disease (ESRD) is growing not only in the USA but worldwide secondary to the global epidemic of diabetes and other causes of kidney disease. Dialysis costs are expensive and access to this care is difficult in developing countries. The majority of patients starting dialysis in low-income countries die and or stop treatment within the first 3 months secondary to financial restraints [1]. Kidney transplantation is the treatment of choice for patients with ESRD and improves long-term survival compared with dialysis [2]. As first shown by Wolfe et al .[ 2], kidney transplantation increases life expectancy as well as quality of life. Later studies have shown that this increase in survival is tied in with the quality of the organ and renal function obtained [3, 4]. However, mortality after transplantation has great variability and is influenced by many known factors (i.e. diabetes), but also unknown factors that contribute to the low R 2 of most models and thus provides an incomplete understanding of the reasons behind this variability. Undoubtedly, an important component of long-term survival is adequate care delivery to kidney transplant recipients. It is likely that better and more frequent specialist care would potentially preserve renal function and also help mitigate mortality from hypertension, diabetes and atherosclerotic disease. In addition, earlier infection and malignancy detection could decrease mortality from these very common causes of death in this population. It is possible that the long-term outcomes of kidney transplant in the USA are hampered by financial barriers leading to non-adherence and lack of access to specialists in the field of transplant. In the USA, Medicare beneficiaries lose their coverage for their immunosuppressive drugs 3 years after transplant and care providers receive low reimbursements for these patients. These factors undoubtedly contribute far greater than in other countries that have nationalized healthcare or provide medication coverage for all constituents including Spain [5]. Ojo et al. evaluated the rates of graft failure and death among USA and Spanish kidney transplant recipients. The authors showed a significant difference among the 10-year graft and patient survival, which was significantly better in the Spanish population. The USA had a greater fraction of transplants going to recipients 70 years of age or older compared with Spain. The two countries had similar rates of glomerular disease and polycystic kidney disease as the primary cause of ESRD. The differences, including recipient age at transplant and a higher number of patients with diabetes as a cause of ESRD, could be strong predictors of patient and allograft survival. Diabetes and hypertension are associated with multiple comorbidities including cardiovascular disease which is the leading cause of death for renal transplant patients. However, it is important to note that the US registry data

Background As more expanded-criteria organ donors are used to bridge the widening gap between organ supply and demand, non-heart-beating (NHB) donors will become increasingly important. The purpose of this study was to analyze renal transplant outcomes using this source of cadaveric (CAD) organs and compare the results with heart-beating organ sources. Methods Data from 98,698 adult CAD renal transplant recipients and 34,531 living donor renal transplant recipients registered in the U. S. Renal Data System database between January 1993 and June 2000 were analyzed. Kaplan-Meier survival curves were used to compare graft and patient survival rates between NHB, CAD, and living donor transplant recipients. Cox proportional hazards models were used to identify risk factors for NHB donor recipients, while adjusting for potential confounding variables. Results Recipients of NHB donor organs experienced nearly twice the incidence of delayed graft function (DGF) compared with heart-beating donors (42.4% vs. 23.3%, respectively). NHB donor transplants experienced comparable allograft survival when compared with CAD transplants at 6 years (73.2% vs. 72.5%, respectively; P=NS); patient survival was greater at 6 years for NHB compared with CAD renal transplant recipients (80.9% vs. 77.8%, respectively; P=NS). Significant factors for allograft loss for NHB donor organ recipients included the following: organ used for repeat transplants; DGF; donor age older than 35 years; and head trauma as a cause of initial injury (relative risk 2.74, 1.90, 1.78, and 1.41, respectively). Conclusions Although exhibiting elevated DGF rates, allograft and patient survival rates of transplants from NHB donor sources are equivalent to those from conventional CAD sources. Donor age, recipient transplant number, female recipient, mechanism of injury, and DGF were the most pertinent variables leading to poor outcomes.

Background. Waiting time on dialysis has been shown to be associated with worse outcomes after living and cadaveric transplantation. To validate and quantify end-stage renal disease (ESRD) time as an independent risk factor for kidney transplantation, we compared the outcome of paired donor kidneys, destined to patients who had ESRD more than 2 years compared to patients who had ESRD less than 6 months. Methods. We analyzed data available from the U.S. Renal Data System database between 1988 and 1998 by Kaplan-Meier estimates and Cox proportional hazards models to quantify the effect of ESRD time on paired cadaveric kidneys and on all cadaveric kidneys compared to living-donated kidneys. Results. Five- and 10-year unadjusted graft survival rates were significantly worse in paired kidney recipients who had undergone more than 24 months of dialysis (58% and 29%, respectively) compared to paired kidney recipients who had undergone less than 6 months of dialysis (78% and 63%, respectively; P

Background. Primary hyperoxaluria is a rare autosomal recessive metabolic disease that often progresses to end-stage renal disease (ESRD). Liver transplantation is curative for patients with the alanine: glyoxylate aminotransferase deficiency. For oxalosis patients with minor enzyme deficiencies, renal transplantation may be the therapy of choice although concern exists about recurrence of oxalosis in the transplanted kidney. To date, previous data has been conflicting with most reports indicating poor renal allograft survival for oxalosis patients who receive a renal transplant alone. To determine whether graft survival in renal transplant recipients with oxalosis is similar to other transplant recipients with other forms of ESRD, we analyzed the United States Renal Data System (USRDS) registry comparing death-censored graft survival for transplant recipients with oxalosis to a reference group with ESRD secondary to glomerulonephritis (GN). Methods. Using the USRDS and the U.S. Scientific Renal Transplant Registry data, we found 190 adult renal transplant recipients from 1988 to 1998 who had oxalosis as their primary diagnosis for their ESRD. Among the patients with oxalosis, 56 patients had a liver transplant followed by a kidney transplant (LKTx) and 134 patients had a kidney transplant alone (KTA). A Cox proportional hazard model was used to estimate patient survival and death-censored graft survival for patients with oxalosis who received a LKTx or a KTA. Unadjusted death-censored graft survival for oxalosis patients with a cadaveric or living-donor KTA or with a LKTx was obtained from Kaplan-Meier analysis. Recipients of solitary kidney transplants with GN served as the reference group. Results. Oxalosis patients receiving a KTA had a significantly worse adjusted death-censored graft survival (47.9%) compared with patients with GN (61%) at 8 years posttransplantation (P

A total of 73,707 primary renal transplants reported to the USRDS between 1988 and 1997 were examined to investigate the cause-specific risk for patient death associated with anti-lymphocyte antibody induction therapy (ABI). Cox proportional hazard models were used to estimate the relative risk of the use of ABI and patient death. All Cox models were corrected for potential confounding variables, such as age, gender, race, HLA mismatch, panel reactive antibody, delayed graft function, cold ischemia time, time since start of dialysis, etiology of end-stage renal disease, cytomegalovirus risk group, donor source (living or cadaveric), era effect, and immunosuppressive therapy. Primary study end points were patient death with functioning graft (DWFG) and overall patient death, including death after graft loss. Early patient death (deaths within the first 6 mo after renal transplantation) and late death (deaths after 6 mo post-renal transplantation) were investigated separately. Additionally, specific causes of death were investigated. ABI was associated with a significant risk for late death after renal transplantation (relative risk [RR] = 1.1; P < 0.001) but not for DWFG (RR = 0.94; P = 0.10). ABI conferred the highest RR for late malignancy-related death (RR = 1.35; P < 0.001). ABI was significantly associated with early deaths due to infection and cardiovascular causes (RR = 1.32 [P < 0.001] and RR = 1.27 [P < 0.001], respectively). Kaplan Meier plots confirmed that the risk of ABI for patient death secondary to infectious complications was increased predominately early after transplantation as opposed to late for malignancy-related death. ABI was associated with a significant relative risk for patient death secondary to cardiovascular causes and infectious complications early in the posttransplant period. In addition, ABI was associated with a significant risk for long-term malignancy-related death. The risk of ABI should be taken in context with potential benefits of this therapy.

BACKGROUND Exposure, safety, and efficacy data from the two everolimus randomized, double-blind phase 3 trials were evaluated to identify a therapeutic concentration range applicable in de novo kidney transplantation. METHODS A total of 695 evaluable everolimus-treated patients received either 0.75 or 1.5 mg bid in addition to corticosteroids and cyclosporine (troughs 150-400 ng/ml in month 1 and 100-300 ng/ml thereafter). A total of 3355 everolimus trough levels (Cmin) were obtained in weeks 1 and 2 and months 1, 2, 3, and 6 after transplantation. Each patient's average Cmin was calculated and the values were divided into quintiles: 1.0-3.4, 3.5-4.5, 4.6-5.7, 5.8-7.7, 7.8-15.0 ng/ml (139 patients per quintile). Efficacy was freedom from biopsy-confirmed acute rejection. Safety measures were maximum total cholesterol and triglyceride levels and minimum leukocyte and platelet counts. A sigmoid exposure-response model was used to test the significance of these Cmin-efficacy and Cmin-safety relationships. RESULTS Freedom from acute rejection was significantly related to Cmin with an incidence of 68% at 1.0-3.4 ng/ml, 81-86% at 3.5-7.7 ng/ml, and 91% at 7.8-15.0 ng/ml (P=0.03). The incidence of hypercholesterolemia, defined as >6.5 mmol/liter, ranged from 76 to 87% over the exposure range without a significant relation to Cmin (P=0.37). The incidence of hypertriglyceridemia, defined as >2.9 mmol/liter, rose from 59 to 77% across the exposure groups (P=0.02). Leukocytopenia, defined as

Tacrolimus and cyclosporine in the microemulsion formulation Neoral® have demonstrated improvements in acute rejection rates after renal transplantation compared with conventional cyclosporine formulation, Sandimmune®. To evaluate whether these drugs are also associated with improvements in chronic allograft failure (CAF) rates, we retrospectively analyzed 32 040 primary renal allograft recipients reported to the United States Renal Data System (USRDS) between 1994 and 1997. Graft loss secondary to CAF was defined as graft loss beyond 6 months post-transplant, censored for death, acute rejection, thrombosis, infections and noncompliance. A Cox proportional hazard model was used to investigate the relationship between graft loss secondary to CAF and the use of conventional cyclosporine formulation, as opposed to cyclosporine microemulsion and tacrolimus (Prograf®). The analysis was corrected for confounding variables, such as acute rejection, sex, race, human leukocyte antigen (HLA) mismatch, % panel reactive antibodies (PRA), delayed graft function (DGF), cold ischemia time, induction therapy, dialysis time, etiology of end-stage renal disease, cytomegalovirus (CMV) risk group, donor source, era effect, and mycophenolate mofetil (MMF) use. Cyclosporine microemulsion use was associated with a significantly lower relative risk (RR = 0.6, CI = 0.5–0.7) for CAF as opposed to conventional cyclosporine formulation. Likewise tacrolimus as compared with conventional cyclosporine formulation was associated with a significantly lower relative risk (RR = 0.7, CI = 0.6–0.8) for CAF. Conventional cyclosporine formulation treatment was associated with a 87.6% adjusted CAF-free survival rate at 4 years. Both tacrolimus and cyclosporine microemulsion were associated with a significantly better adjusted CAF-free survival at 4 years (91.4 and 92.4%, respectively). Both cyclosporine microemulsion and tacrolimus are associated with improved graft survival and a decreased relative risk for CAF when compared with the older conventional cyclosporine formulation. This association is independent of the use of MMF or changes in era.

Introduction Renal transplant recipients with elevated body mass index (BMI) have been shown to have inferior patient survival as compared to patients with lower BMI. However, previous studies could not establish a link between increased BMI and decreased death censored graft survival. Obesity in nontransplant patients has been associated with hypertension, hyperlipidemia, type II diabetes, proteinuria and glomerulopathy. Given this evidence it is possible that renal transplant recipients with an elevated BMI may have worse long term graft survival. To investigate this hypothesis we retrospectively analyzed 51,927 primary, adult renal transplants registered in the USRDS. Methods BMI at date of transplant was calculated for all patients using BMI=body weight (in kg)=.stature (height, in meters) squared. BMI values were further categorized into 11 categories: below 18, from 18 to 36 at 2 unit increments, and above 36 kg/m2. Primary study end points were graft and patient survival. Secondary study end points were death censored graft survival, chronic allograft failure, delayed graft function, and acute rejection (AR). Cox proportional hazard and logistic regression models investigated the link between categorized BMI and the study end points correcting for potential confounding variables. Results BMI showed a very strong association with outcomes after renal transplantation. The extremes of very high and very low BMI were associated with significantly worse patient and graft survival. The same was true for death censored graft survival and chronic allograft failure. Elevated BMI was also associated with an increased risk for delayed graft function while lower BMI was significantly protective. Acute rejection did not show any significant association with BMI. Conclusions BMI has a very strong association with outcomes after renal transplantation independent of most of the known risk factors for patient and graft survival. The extremes of very high and very low BMI before renal transplantation are important risk factors for patient and graft survival. It is important to note that elevated BMI was significantly associated with worse graft survival independent of patient survival. Whether prospective weight adjustment before renal transplantation can favorably affect posttransplant risk needs to be assessed by further studies.

The ASCERTAIN study has confirmed previous findings that conversion from calcineurin inhibitors to mammalian target of rapamycin (mTOR) inhibitors does not seem to improve glomerular filtration rate in renal transplant recipients, although it does seem beneficial in patients with better renal function at baseline. Questions remain regarding the role of mTOR inhibitors in kidney transplantation.

Prospective clinical trials are constructed with high levels of internal validity. Sample size and power considerations usually address primary endpoints. Primary endpoints have traditionally included events that are becoming increasingly less common and thus have led to growing use of composite endpoints and noninferiority trial designs in transplantation. This approach may mask real clinical benefit in one or the other domain with regard to either clinically relevant secondary endpoints or other unexpected findings. In addition, endpoints solely chosen based on power considerations are prone to misjudgment of actual treatment effect size as well as consistency of that effect. In the instances where treatment effects may have been underestimated, valuable information may be lost if buried within a composite endpoint. In all these cases, analyses and post hoc analyses of data become relevant in informing practitioners about clinical benefits or safety signals that may not be captured by the primary endpoint. On the other hand, there are many pitfalls in using post hoc determined endpoints. This short review is meant to allow readers to appreciate post hoc analysis not as an entity with a single approach, but rather as an analysis with unique limitations and strengths that often raise new questions to be addressed in further inquiries.

Purpose of review Vascularized composite tissue allografts (CTAs) provide excellent restorative options for patients with limb loss and other deformities. Acute rejection remains common with CTA and immunosuppression is used in an attempt to prevent rejection. This has created ethical debates regarding the use of intensive immunosuppression for a nonlife-saving procedure. This highlights the need for newer immunosuppressive strategies for CTA, which are described in this review. Recent findings Recent studies have looked into immunomodulation and tolerance to decrease toxicity of immunosuppression. Both strategies have had some success but have their own limitations. Although immunomodulation and decrease in immunosuppression decreases toxicity, it has been associated with higher rates of rejection. Induction of tolerance has achieved some initial success, but the initial conditioning regimens are associated with significant morbidity. Summary Although recent advancements have been made in the immunosuppressive strategies in CTA, the ideal immunosuppression strategy with low toxicity and infection risk but with the ability to prevent acute and chronic rejection is yet to be discovered.

The significance of BK viruria and viremia in non-renal solid organ transplants is poorly understood. A systematic review was performed reviewing the incidence and implications of BK virus replication in non-renal solid organ transplants. Ninety-seven studies were identified, of which 18 including lung, heart, liver and pancreas transplants were included. The overall incidence of BK viruria and viremia was 20% and 3% respectively and 17 cases of BK nephropathy were identified. Heart transplant recipients had a higher overall incidence of BK viremia than other non-renal organ types, and the majority of cases of BK virus-associated nephropathy were in heart transplant recipients. The incidence of BK viremia was significantly lower in non-renal solid organ transplants than that of renal transplant recipients and BK virus-associated nephropathy was rare. BK virus-associated nephropathy may be considered in heart transplant recipients who have unexplained and persistent renal dysfunction not attributable to other causes.

Kidney transplantation is agreed upon as the best treatment available for most patients with end-stage renal disease (ESRD). It not only improves quality of life (Am J Kidney Dis 15(3):201–8, 1990; Kidney Int 50(1):235–42, 1996; N Engl J Med 28;312(9):553–9, 1985; Transplantation 54(4):656–60, 1992) of our patients and reduces medical expense (Kidney Int 50(1):235–42, 1996; Semin Nephrol 12(3):284–9, 1992) but also has shown to be a life-prolonging procedure. Multiple studies using renal transplant recipients with dialysis patients have found that patient survival is clearly better with renal transplantation than with dialysis (Kidney Int 21(1):78–83, 1982; Transplantation. 60(12):1389–94, 1995; Nephrol Dial Transplant 12(8):1672–9, 1997; Kidney Int 53(3):767–72, 1998).

Background. Basiliximab (Simulect), a high-affinity chimeric, monoclonal antibody directed against the alpha chain of human interleukin-2 receptor (CD25), reduces the incidence of acute renal allograft rejection when used in combination with cyclosporine (Neoral) and steroids. This study was designed to compare the safety and efficacy of basiliximab to polyclonal anti-T-cell (ATGAM) therapy for the prevention of acute rejection in de novo renal transplant recipients. Methods. This 1-year, open-label, randomized trial was conducted in recipients of cadaveric or living-related donor renal transplants. All patients received cyclosporine (Neoral), mycophenolate mofetil (Cell-Cept, MMF), and corticosteroids. Patients who were randomized to basiliximab therapy received a 20 mg i.v. bolus dose on days 0 and 4, and the majority of patients were initiated on cyclosporine within 48 hr of transplantation. Patients who were randomized to antithymocyte globulin therapy (ATGAM, ATG) received 15 mg/day i.v. within 48 hr of transplant and continued treatment for up to 14 days; ATG was stopped once therapeutic cyclosporine blood levels were achieved. The initiation of cyclosporine use was delayed in the ATG group until renal function was established (serum creatinine

Introduction Although multiple studies of demographic variables have been associated with allograft thrombosis, these results are not routinely reproducible. Are ESRD patients with hypercoagulable states (HCS) (antithrombin III deficiency, protein S or C deficiency, activated protein C resistance, and anticardiolipin antibodies) at predictably greater risk for allograft thrombosis? Methods Between 1996 and 1999, all renal transplant candidates were screened for hypercoagulability risk factors [HRF] (multiple arteriovenous access thromboses, prior deep vein thrombosis, prior allograft thrombosis, collagen vascular disease, multiple miscarriages, diabetes, autoimmune disease, and Fabry's disease). HRF(+) candidates were then tested for HCS status. We administered preemptive posttransplant i.v. Heparin in HCS(+) patients and observed the impact of this intervention upon the incidence of allograft thrombosis. We compared demographic data and incidence of allograft thrombosis in an historic control (346 patients transplanted between June 31, 1992, and March 5, 1996) not tested for HCS and a study cohort (502 patients transplanted between March 6, 1996, and June 31, 1999) prospectively screened for HRF. HRF(+) patients who were HCS(+) in the study cohort received i.v. heparin immediately after transplant and p.o. warfarin as outpatients. Results Demographic characteristics previously implicated in allograft thrombosis were equivalently distributed in both cohorts with the exceptions that more living-donor transplants (33.1% vs. 15.3%) were performed in study cohort, CIT>24 hr occurred in more control patients (37.3% vs. 22.1%) and more study patients (16.7% vs. 0%) received tacrolimus. Hypercoagulable states were found upon reevaluating five of seven controls (71.4%), who lost prior allografts to thrombosis. Hypercoagulable states were prospectively detected in 10 study patients with hypercoagulability risk factors. Most (9 of 10) study patients receiving anticoagulation have achieved long-term allograft function. Study group allograft thrombosis incidence was reduced (1.59% vs. 4.05%). Hypercoagulable states were demonstrated in most episodes of allograft thrombosis. Control patients who lost prior allografts to thrombosis were anticoagulated after retransplantation and 100% achieved long-term allograft function. Conclusions Long-term allograft function has been achieved in 90% of study patients when prophylactically anticoagulating study patients with hypercoagulable states. A 2.6-fold reduction in the expected incidence of allograft thrombosis was observed in anticoagulated patients with hypercoagulable states.

Background The effects of three doses of RAD (40-O-[2-hydroxyethyl]-rapamycin), a novel macrolide with potent immunosuppressive and antiproliferative properties, on the incidence and severity of acute rejection episodes as well as its tolerability were evaluated in a dose-ranging study in de novo renal transplant recipients. Methods In this double-blind, parallel group, multicenter study, recipients were randomized to receive 1 mg, 2 mg, or 4 mg/day of RAD in combination with Neoral (cyclosporine, USP MODIFIED) and corticosteroids. The incidence and severity of biopsy-proven acute rejection episodes, graft survival, patient survival, infection rates, laboratory measurements, and adverse events were compared across groups after 6 months of therapy. Results Among the 103 recipients, patients receiving 1, 2, or 4 mg/day experienced a 32.4%, 14.7%, or 25.7% incidence of biopsy-proven acute rejection episodes within the first 6 months posttransplantation, respectively. Even though the study was not powered to demonstrate efficacy, the incidence of moderate and severe acute rejection episodes was found to be significantly lower among patients in the 2 mg and 4 mg/day groups than in the 1 mg/day group (P=0.002 and P=0.006, respectively). Overall graft and patient survival rates were excellent. RAD was generally well tolerated. Although blood lipid levels increased in all groups, changes were manageable with lipid-lowering agents and did not warrant discontinuation of study medication. The incidence of viral and fungal infections was low; however, it was higher among recipients treated with 4 mg/day. Conclusions In combination with Neoral and corticosteroids, RAD doses of 2 mg and 4 mg/day resulted in lower rates of acute rejection episodes and efficacy failure than the 1 mg/day dose and were significantly more effective in reducing the severity of rejection. Large-scale, controlled, follow-up studies are currently in progress to confirm these initial findings.

Background Calcineurin inhibitors (CNI) and azole antifungal agents have been reported to interact in a disparate manner. The azole dose and route and the level of involvement of the liver and intestines have been implicated, although data are limited. A significant interaction may result in CNI toxicity, and withdrawal of the azole may result in subtherapeutic CNI concentrations. Fluconazole, available in both intravenous and oral formulations, is commonly used in transplant recipients and is ideal for determining the presence of a disparate effect on CNI concentrations. We retrospectively investigated the interaction of CNIs with fluconazole, evaluating CNI blood troughs corrected for daily CNI dose, the factors influencing the interaction, and the effect on clinical outcomes in renal and simultaneous pancreas kidney transplant recipients. Methods Twenty-eight patients received a CNI and fluconazole during the calendar year 1999, but only 19 patients had documented CNI blood troughs and outpatient follow-up. There were 25 episodes of use in the 19 included patients. CNI blood troughs were evaluated for changes induced by fluconazole, given by both routes, and clinical outcomes were tracked. Results Data demonstrated both intravenous and oral fluconazole alter CNI blood concentrations. Two metabolic patterns were observed, and we termed these convergent and divergent. Divergent metabolizers did not have significant interaction (n=5), and convergent metabolizers did have a significant interaction (n=15). One patient had a divergent episode after a previous convergent episode. The main contributors to the lack of interaction appeared to be female sex and African American ethnicity. Additionally, tacrolimus levels were significantly more affected than cyclosporine, during and after fluconazole administration. No patient experienced nephrotoxicity or cellular rejection related to antifungal therapy. Conclusions Oral and intravenous fluconazole appear to increase oral CNI trough concentrations to a similar extent even after adjusting for daily calcineurin dose. These interactions appear to be chiefly influenced by sex and ethnicity. Further prospective study is necessary to clarify this issue.