John J. Friedewald

Kidney Transplantation as Primary Therapy for End-Stage Renal Disease: A National Kidney Foundation/Kidney Disease Outcomes Quality Initiative (NKF/KDOQI™) Conference

BACKGROUND AND OBJECTIVES Kidney transplantation is the most desired and cost-effective modality of renal replacement therapy for patients with irreversible chronic kidney failure (end-stage renal disease, stage 5 chronic kidney disease). Despite emerging evidence that the best outcomes accrue to patients who receive a transplant early in the course of renal replacement therapy, only 2.5% of incident patients with end-stage renal disease undergo transplantation as their initial modality of treatment, a figure largely unchanged for at least a decade. DESIGN, SETTING, PARTICIPANTS, & MEASUREMENTS The National Kidney Foundation convened a Kidney Disease Outcomes Quality Initiative (KDOQI) conference in Washington, DC, March 19 through 20, 2007, to examine the issue. Fifty-two participants representing transplant centers, dialysis providers, and payers were divided into three work groups to address the impact of early transplantation on the chronic kidney disease paradigm, educational needs of patients and professionals, and finances of renal replacement therapy. RESULTS Participants explored the benefits of early transplantation on costs and outcomes, identified current barriers (at multiple levels) that impede access to early transplantation, and recommended specific interventions to overcome those barriers. CONCLUSIONS With implementation of early education, referral to a transplant center coincident with creation of vascular access, timely transplant evaluation, and identification of potential living donors, early transplantation can be an option for substantially more patients with chronic kidney disease.

Urinary-Cell mRNA Profile and Acute Cellular Rejection in Kidney Allografts

BACKGROUND The standard test for the diagnosis of acute rejection in kidney transplants is the renal biopsy. Noninvasive tests would be preferable. METHODS We prospectively collected 4300 urine specimens from 485 kidney-graft recipients from day 3 through month 12 after transplantation. Messenger RNA (mRNA) levels were measured in urinary cells and correlated with allograft-rejection status with the use of logistic regression. RESULTS A three-gene signature of 18S ribosomal (rRNA)-normalized measures of CD3ε mRNA and interferon-inducible protein 10 (IP-10) mRNA, and 18S rRNA discriminated between biopsy specimens showing acute cellular rejection and those not showing rejection (area under the curve [AUC], 0.85; 95% confidence interval [CI], 0.78 to 0.91; P<0.001 by receiver-operating-characteristic curve analysis). The cross-validation estimate of the AUC was 0.83 by bootstrap resampling, and the Hosmer-Lemeshow test indicated good fit (P=0.77). In an external-validation data set, the AUC was 0.74 (95% CI, 0.61 to 0.86; P<0.001) and did not differ significantly from the AUC in our primary data set (P=0.13). The signature distinguished acute cellular rejection from acute antibody-mediated rejection and borderline rejection (AUC, 0.78; 95% CI, 0.68 to 0.89; P<0.001). It also distinguished patients who received anti-interleukin-2 receptor antibodies from those who received T-cell-depleting antibodies (P<0.001) and was diagnostic of acute cellular rejection in both groups. Urinary tract infection did not affect the signature (P=0.69). The average trajectory of the signature in repeated urine samples remained below the diagnostic threshold for acute cellular rejection in the group of patients with no rejection, but in the group with rejection, there was a sharp rise during the weeks before the biopsy showing rejection (P<0.001). CONCLUSIONS A molecular signature of CD3ε mRNA, IP-10 mRNA, and 18S rRNA levels in urinary cells appears to be diagnostic and prognostic of acute cellular rejection in kidney allografts. (Funded by the National Institutes of Health and others.).

New National Allocation Policy for Deceased Donor Kidneys in the United States and Possible Effect on Patient Outcomes

In 2013, the Organ Procurement and Transplantation Network in the United States approved a new national deceased donor kidney allocation policy that introduces the kidney donor profile index (KDPI), which gives scores of 0%-100% based on 10 donor factors. Kidneys with lower KDPI scores are associated with better post-transplant survival. Important features of the new policy include first allocating kidneys from donors with a KDPI≤20% to candidates in the top 20th percentile of estimated post-transplant survival, adding waiting time from dialysis initiation, conferring priority points for a calculated panel-reactive antibody (CPRA)>19%, broader sharing of kidneys for candidates with a CPRA≥99%, broader sharing of kidneys from donors with a KDPI>85%, eliminating the payback system, and allocating blood type A2 and A2B kidneys to blood type B candidates. We simulated the distribution of kidneys under the new policy compared with the current allocation policy. The simulation showed increases in projected median allograft years of life with the new policy (9.07 years) compared with the current policy (8.82 years). With the new policy, candidates with a CPRA>20%, with blood type B, and aged 18-49 years were more likely to undergo transplant, but transplants declined in candidates aged 50-64 years (4.1% decline) and ≥65 years (2.7% decline). These simulations demonstrate that the new deceased donor kidney allocation policy may improve overall post-transplant survival and access for highly sensitized candidates, with minimal effects on access to transplant by race/ethnicity and declines in kidney allocation for candidates aged ≥50 years.

Simultaneous Liver-Kidney Transplantation Summit: Current State and Future Directions

Although previous consensus recommendations have helped define patients who would benefit from simultaneous liver–kidney transplantation (SLK), there is a current need to reassess published guidelines for SLK because of continuing increase in proportion of liver transplant candidates with renal dysfunction and ongoing donor organ shortage. The purpose of this consensus meeting was to critically evaluate published and registry data regarding patient and renal outcomes following liver transplantation alone or SLK in liver transplant recipients with renal dysfunction. Modifications to the current guidelines for SLK and a research agenda were proposed.

Assessing Antibody Strength: Comparison of MFI, C1q, and Titer Information

The presence of donor‐specific HLA antibodies before or after transplantation may have different implications based on the antibody strength. Yet, current approaches do not provide information regarding the true antibody strength as defined by antigen–antibody dissociation rate. To assess currently available methods, we compared between neat mean fluorescence intensity (MFI) values, C1q MFI values, ethylenediaminetetraacetic acid (EDTA)‐treated samples, as well as titration studies and peak MFI values of over 7000 Luminex‐based single‐antigen HLA antibody data points. Our results indicate that neat MFI values do not always accurately depict antibody strength. We further showed that EDTA treatment (6%) does not always remove all inhibitory factors compared with C1q or titration studies. In this study of patients presenting with multiple antibody specificities, a prozone effect was observed in 71% of the cohort (usually not affecting all antibody specificities within a single serum sample, though). Similar to titration studies, the C1q assay was able to address the issue of potential inhibition; however, its limitation is its low sensitivity and inability to detect the presence of weak antibodies. Titration studies are the only method among the approaches used in this study to provide information suggesting antigen–antibody dissociation rates and are, therefore, likely to provide better indication of true antibody strength.

Randomized Phase 2b Trial of Tofacitinib (CP‐690,550) in De Novo Kidney Transplant Patients: Efficacy, Renal Function and Safety at 1 Year

In this Phase 2b study, 331 low‐to‐moderate risk de novo kidney transplant patients (approximately 60% deceased donors) were randomized to a more intensive (MI) or less intensive (LI) regimen of tofacitinib (CP‐690, 550), an oral Janus kinase inhibitor or cyclosporine (CsA). All patients received basiliximab induction, mycophenolic acid and corticosteroids. Primary endpoints were: incidence of biopsy‐proven acute rejection (BPAR) with a serum creatinine increase of ≥0.3 mg/dL and ≥20% (clinical BPAR) at Month 6 and measured GFR at Month 12. Similar 6‐month incidences of clinical BPAR (11%, 7% and 9%) were observed for MI, LI and CsA. Measured GFRs were higher (p < 0.01) at Month 12 for MI and LI versus CsA (65 mL/min, 65 mL/min vs. 54 mL/min). Fewer (p < 0.05) patients in MI or LI developed chronic allograft nephropathy at Month 12 compared with CsA (25%, 24% vs. 48%). Serious infections developed in 45%, 37% and 25% of patients in MI, LI and CsA, respectively. Anemia, neutropenia and posttransplant lymphoproliferative disorder occurred more frequently in MI and LI compared with CsA. Tofacitinib was equivalent to CsA in preventing acute rejection, was associated with improved renal function and less chronic allograft histological injury, but had side‐effects at the doses evaluated.

Transmission of human immunodeficiency virus and hepatitis C virus from an organ donor to four transplant recipients.

In 2007, a previously uninfected kidney transplant recipient tested positive for human immunodeficiency virus type 1 (HIV) and hepatitis C virus (HCV) infection. Clinical information of the organ donor and the recipients was collected by medical record review. Sera from recipients and donor were tested for serologic and nucleic acid‐based markers of HIV and HCV infection, and isolates were compared for genetic relatedness. Routine donor serologic screening for HIV and HCV infection was negative; the donors only known risk factor for HIV was having sex with another man. Four organs (two kidneys, liver and heart) were transplanted to four recipients. Nucleic acid testing (NAT) of donor sera and posttransplant sera from all recipients were positive for HIV and HCV. HIV nucleotide sequences were indistinguishable between the donor and four recipients, and HCV subgenomic sequences clustered closely together. Two patients subsequently died and the transplanted organs failed in the other two patients. This is the first recognized cotransmission of HIV and HCV from an organ donor to transplant recipients. Routine posttransplant HIV and HCV serological testing and NAT of recipients of organs from donors with suspected risk factors should be considered as routine practice.

The complexity of human leukocyte antigen (HLA)-DQ antibodies and its effect on virtual crossmatching.

Background. We previously reported that in patients possessing human leukocyte antigen (HLA)-DQ-directed antibodies, the target molecule may include the patient’s own DQ&bgr; chain if it is paired with non–self-DQ&agr; chain, thus forming a different DQ target. Herein, we sought to assess the breadth of this phenomenon. Methods. Serum samples from 104 patients awaiting kidney transplantation, known to have DQ antibodies, were studied. Antibody identification was performed using luminex-based HLA class II single-antigen bead assays from two vendors; DQA1/DQB1 typing was performed using luminex polymerase chain reaction – sequence specific oligo prob hybridization (PCR-SSO) technology. Results. A total of 71% of the 104 serum samples studied contained antibodies reactive against test beads coated with the patient’s own DQ&agr;- or &bgr;-chain components. Of those, 35 patients (34%) exhibited antibodies to their own DQ&bgr; chain when in combination with non–self-DQ&agr; chains; and 64 patients (62%) had antibodies to their own DQ&agr; chain when in combination with non–self-DQ&bgr; chains. This is a striking observation. Conclusions. To the best of our knowledge, this is the first systematic, high-resolution evaluation of DQ antibody repertoire. With the expansion of virtual crossmatching, particularly in the context of a national registry, the need for more detailed DQ antibody or antigen evaluation is critical to improve operational efficiency and patient outcomes.

Solid-organ transplantation in older adults: Current status and future research

An increasing number of patients older than 65 years are referred for and have access to organ transplantation, and an increasing number of older adults are donating organs. Although short‐term outcomes are similar in older versus younger transplant recipients, older donor or recipient age is associated with inferior long‐term outcomes. However, age is often a proxy for other factors that might predict poor outcomes more strongly and better identify patients at risk for adverse events. Approaches to transplantation in older adults vary across programs, but despite recent gains in access and the increased use of marginal organs, older patients remain less likely than other groups to receive a transplant, and those who do are highly selected. Moreover, few studies have addressed geriatric issues in transplant patient selection or management, or the implications on health span and disability when patients age to late life with a transplanted organ. This paper summarizes a recent trans‐disciplinary workshop held by ASP, in collaboration with NHLBI, NIA, NIAID, NIDDK and AGS, to address issues related to kidney, liver, lung, or heart transplantation in older adults and to propose a research agenda in these areas.

The Kidney Allocation System

The current kidney allocation system for transplants is outdated and has not evolved to reflect the changing demographics of patients on the waiting list. This article proposes a new system for kidney allocation, which more appropriately incorporates the biology of highly sensitized patients into the waiting-time scoring algorithm. This system will significantly reduce mismatches between possible donor kidney longevity and life expectancy of recipients, and makes incremental advances toward more geographic sharing. The proposed system makes significant progress toward eliminating deficiencies in the current system, and has the potential to increase the supply of available kidneys.