Long-term Safety in Epstein-Barr Virus-Seropositive Kidney-only Transplant Recipients Treated With Belatacept in Clinical Practice: Final Study Results From the ENLiST Registry

Background

Belatacept, a selective T-cell costimulation blocker, was associated with improved survival and renal function but also with a risk of posttransplant lymphoproliferative disorder (PTLD) in adult kidney transplant recipients in phase 3 trials. This registry examined long-term safety in Epstein-Barr virus (EBV)-seropositive kidney transplant recipients treated with belatacept.

Methods

This US-based, prospective, voluntary, multicenter registry (Evaluating Nulojix Long-Term Safety in Transplant [ENLiST]) included adult EBV-seropositive kidney-only transplant recipients treated de novo (within 14 d of transplantation) with belatacept. Primary objectives were to estimate incidence rates of confirmed PTLD, central nervous system (CNS) PTLD, and progressive multifocal encephalopathy (PML). The minimum follow-up was 2 y.

Results

Of 985 enrolled transplant recipients, 933 EBV-seropositive patients received belatacept, with 523 (56.1%) receiving concomitant tacrolimus at transplant (for up to 12 mo). By study end, 3 cases of non-CNS PTLD (incidence rate, 0.08/100 person-years), 1 case of CNS PTLD (0.03/100 person-years), and no cases of PML had been reported. Two patients with non-CNS PTLD received concomitant belatacept and tacrolimus and 1 received belatacept and lymphocyte-depleting therapy. Incidence rates were comparable between patients who received concomitant belatacept and tacrolimus and those who did not receive tacrolimus (0.09/100 person-years and 0.07/100 person-years, respectively; P = 0.96). Two of 4 patients with PTLD died, and 2 were alive at the end of the study. Cumulatively, 131 graft losses or deaths were reported by study end.

Conclusions

Our results from the ENLiST registry, a large, prospective real-world study, showed that the incidence rates of PTLD and CNS PTLD in belatacept-treated EBV-seropositive transplant recipients were consistent with findings from previous phase 3 trials.

Posoleucel in Kidney Transplant Recipients with BK Viremia: Multicenter, Randomized, Double-Blind, Placebo-Controlled Phase 2 Trial

Key Points

Background

Kidney transplant recipients with BK virus infection are at risk of developing BK virus–associated nephropathy, allograft rejection, and subsequent graft loss. There are no approved treatments for BK virus infection. Posoleucel is an off-the-shelf, allogeneic, multivirus-specific T-cell investigational therapy targeting BK virus, as well as five other opportunistic viruses: adenovirus, cytomegalovirus, Epstein–Barr virus, human herpesvirus 6, and John Cunningham virus.

Methods

In this phase 2, double-blind study, kidney transplant recipients with BK viremia were randomized 1:1:1 to receive posoleucel weekly for 3 weeks and then every 14 days (bi-weekly dosing) or every 28 days (monthly dosing) or placebo for 12 weeks. Participants were followed for 12 weeks after completing treatment. The primary objective was safety; the secondary objective was plasma BK viral load reduction.

Results

Sixty-one participants were randomized and dosed. Baseline characteristics were similar across groups. No deaths, graft-versus-host disease, or cytokine release syndrome occurred. The proportion of patients who had adverse events (AEs) judged by the investigators to be treatment-related was slightly lower in recipients of posoleucel: 20% (4 of 20 patients) and 18% (4 of 22) in those infused on a bi-weekly and monthly schedule, respectively, and 26% (5 of 19) in placebo recipients. None of the grade 3–4 AEs or serious AEs in any group were deemed treatment-related. No deaths, graft-versus-host disease, or cytokine release syndrome occurred. Three participants had allograft rejection, but none were deemed treatment-related by investigators. In posoleucel recipients, BK viremia reduction was associated with an increase in the circulating frequency of BK virus–specific T cells, and the presence and persistence of posoleucel was confirmed by T-cell receptor sequencing.

Conclusions

Posoleucel was generally safe, well tolerated, and associated with a larger reduction of BK viremia compared with placebo. Limitations of this study include the relatively short duration of follow-up and lack of power to detect significant differences in clinical outcomes.

Clinical Trial registry name and registration number:

Study of Posoleucel (Formerly Known as ALVR105; Viralym-M) in Kidney Transplant Patients With BK Viremia, NCT04605484.

Blood immunophenotyping identifies distinct kidney histopathology and outcomes in patients with lupus nephritis

Lupus nephritis (LN) is a frequent manifestation of systemic lupus erythematosus, and fewer than half of patients achieve complete renal response with standard immunosuppressants. Identifying non-invasive, blood-based pathologic immune alterations associated with renal injury could aid therapeutic decisions. Here, we used mass cytometry immunophenotyping of peripheral blood mononuclear cells in 145 patients with biopsy-proven LN and 40 healthy controls to evaluate the heterogeneity of immune activation in patients with LN and to identify correlates of renal parameters and treatment response. Unbiased analysis identified 3 immunologically distinct groups of patients with LN that were associated with different patterns of histopathology, renal cell infiltrates, urine proteomic profiles, and treatment response at one year. Patients with enriched circulating granzyme B+ T cells at baseline showed more severe disease and increased numbers of activated CD8 T cells in the kidney, yet they had the highest likelihood of treatment response. A second group characterized primarily by a high type I interferon signature had a lower likelihood of response to therapy, while a third group appeared immunologically inactive by immunophenotyping at enrollment but with chronic renal injuries. Main immune profiles could be distilled down to 5 simple cytometric parameters that recapitulate several of the associations, highlighting the potential for blood immune profiling to translate to clinically useful non-invasive metrics to assess immune-mediated disease in LN.

Defining the T cell transcriptional landscape in pediatric liver transplant rejection at single cell resolution

Acute cellular rejection (ACR) affects >80% of pediatric liver transplant recipients within 5 years, and late ACR is associated with graft failure. Traditional anti-rejection therapy for late ACR is ineffective and has remained unchanged for six decades. Although CD8+ T cells promote late ACR, little has been done to define their specificity and gene expression. Here, we used single-cell sequencing and immune repertoire profiling (10X Genomics) on 30 cryopreserved 16G liver biopsies from 14 patients (5 pre-transplant or with no ACR, 9 with ACR). We identified expanded intragraft CD8+ T cell clonotypes (CD8EXP) and their gene expression profiles in response to anti-rejection treatment. Notably, we found that expanded CD8+ clonotypes (CD8EXP) bore markers of effector and CD56hiCD161- 'NK-like' T cells, retaining their clonotype identity and phenotype in subsequent biopsies from the same patients despite histologic ACR resolution. CD8EXP clonotypes localized to portal infiltrates during active ACR, and persisted in the lobule after histologic ACR resolution. CellPhoneDB analysis revealed differential crosstalk between KC and CD8EXP during late ACR, with activation of the LTB-LTBR pathway and downregulation of TGFß signaling. Therefore, persistently-detected intragraft CD8EXP clones remain active despite ACR treatment and may contribute to long-term allograft fibrosis and failure of operational tolerance.

The Proteasome Inhibitor Bortezomib Induces p53-Dependent Apoptosis in Activated B Cells

The proteasome inhibitor bortezomib (BTZ) is proposed to deplete activated B cells and plasma cells. However, a complete picture of the mechanisms underlying BTZ-induced apoptosis in B lineage cells remains to be established. In this study, using a direct in vitro approach, we show that deletion of the tumor suppressor and cell cycle regulator p53 rescues recently activated mouse B cells from BTZ-induced apoptosis. Furthermore, BTZ treatment elevated intracellular p53 levels, and p53 deletion constrained apoptosis, as recently stimulated cells first transitioned from the G1 to S phase of the cell cycle. Moreover, combined inhibition of the p53-associated cell cycle regulators and E3 ligases MDM2 and anaphase-promoting complex/cyclosome induced cell death in postdivision B cells. Our results reveal that efficient cell cycle progression of activated B cells requires proteasome-driven inhibition of p53. Consequently, BTZ-mediated interference of proteostasis unleashes a p53-dependent cell cycle-associated death mechanism in recently activated B cells.

Prior viral infection primes cross-reactive CD8+ T cells that respond to mouse heart allografts

Introduction

Significant evidence suggests a connection between transplant rejection and the presence of high levels of pre-existing memory T cells. Viral infection can elicit viral-specific memory T cells that cross-react with allo-MHC capable of driving allograft rejection in mice. Despite these advances, and despite their critical role in transplant rejection, a systematic study of allo-reactive memory T cells, their specificities, and the role of cross-reactivity with viral antigens has not been performed.

Methods

Here, we established a model to identify, isolate, and characterize cross-reactive T cells using Nur77 reporter mice (C57BL/6 background), which transiently express GFP exclusively upon TCR engagement. We infected Nur77 mice with lymphocytic choriomeningitis virus (LCMV-Armstrong) to generate a robust memory compartment, where quiescent LCMV-specific memory CD8+ T cells could be readily tracked with MHC tetramer staining. Then, we transplanted LCMV immune mice with allogeneic hearts and monitored expression of GFP within MHC-tetramer defined viral-specific T cells as an indicator of their ability to cross-react with alloantigens.

Results

Strikingly, prior LCMV infection significantly increased the kinetics and magnitude of rejection as well as CD8+ T cell recruitment into allogeneic, but not syngeneic, transplanted hearts, relative to non-infected controls. Interestingly, as early as day 1 after allogeneic heart transplant an average of ~8% of MHC-tetramer+ CD8+ T cells expressed GFP, in contrast to syngeneic heart transplants, where the frequency of viral-specific CD8+ T cells that were GFP+ was <1%. These data show that a significant percentage of viral-specific memory CD8+ T cells expressed T cell receptors that also recognized alloantigens in vivo. Notably, the frequency of cross-reactive CD8+ T cells differed depending upon the viral epitope. Further, TCR sequences derived from cross-reactive T cells harbored distinctive motifs that may provide insight into cross-reactivity and allo-specificity.

Discussion

In sum, we have established a mouse model to track viral-specific, allo-specific, and cross-reactive T cells; revealing that prior infection elicits substantial numbers of viral-specific T cells that cross-react to alloantigen, respond very early after transplant, and may promote rapid rejection.

Carfilzomib-based antibody mediated rejection therapy in pediatric kidney transplant recipients

BACKGROUND

To date, the evidence for proteasome-inhibitor (PI) based antibody mediated rejection (AMR) therapy has been with the first-generation PI bortezomib. Results have demonstrated encouraging efficacy for early AMR with lesser efficacy for late AMR. Unfortunately, bortezomib is associated with dose-limiting adverse effects in some patients. We report use of the second generation proteosome inhibitor carfilzomib for AMR treatment in two pediatric patients with a kidney transplant.

METHODS

The clinical data on two patients who experienced dose limiting toxicities from bortezomib were collected along with their short- and long-term outcomes.

RESULTS

A two-year-old female with simultaneous AMR, multiple de novo DSAs (DR53 MFI 3900, DQ9 MFI 6600, DR15 2200, DR51 MFI 1900) and T-cell mediated rejection (TCMR) completed three carfilzomib cycles and experienced stage 1 acute kidney injury after the first two cycles. At 1 year follow up, all DSAs resolved, and her kidney function returned to baseline without recurrence. A 17-year-old female also developed AMR with multiple de novo DSAs (DQ5 MFI 9900, DQ6 MFI 9800, DQA*01 MFI 9900). She completed two carfilzomib cycles, which were associated with acute kidney injury. She had resolution of rejection on biopsy and decreased but persistent DSAs on follow-up.

CONCLUSIONS

Carfilzomib treatment for bortezomib-refractory rejection and/or bortezomib toxicity may provide DSA elimination or reduction, but also appears to be associated with nephrotoxicity. Clinical development of carfilzomib for AMR will require a better understanding of efficacy and development of approaches to mitigate nephrotoxicity.

Single cell transcriptomic analysis of renal allograft rejection reveals insights into intragraft TCR clonality

Bulk analysis of renal allograft biopsies (rBx) identified RNA transcripts associated with acute cellular rejection (ACR); however, these lacked cellular context critical to mechanistic understanding of how rejection occurs despite immunosuppression (IS). We performed combined single cell RNA transcriptomic and TCRα/β sequencing on rBx from patients with ACR under differing IS: tacrolimus, iscalimab, and belatacept. We found distinct CD8+ T cell phenotypes (e.g., effector, memory, exhausted) depending upon IS type, particularly within clonally expanded cells (CD8EXP). Gene expression of CD8EXP identified therapeutic targets that were influenced by IS type. TCR analysis revealed a highly restricted number of CD8EXP, independent of HLA mismatch or IS type. Subcloning of TCRα/β cDNAs from CD8EXP into Jurkat76 cells (TCR-/-) conferred alloreactivity by mixed lymphocyte reaction. Analysis of sequential rBx samples revealed persistence of CD8EXP that decreased, but were not eliminated, after successful anti-rejection therapy. In contrast, CD8EXP were maintained in treatment-refractory rejection. Finally, most rBx-derived CD8EXP were also observed in matching urine samples, providing precedent for using urine-derived CD8EXP as a surrogate for those found in the rejecting allograft. Overall, our data define the clonal CD8+ T cell response to ACR, paving the next steps to improve detection, assessment, and treatment of rejection.

T-cell infiltrate intensity is associated with delayed response to treatment in late acute cellular rejection in pediatric liver transplant recipients

BACKGROUND

Late acute cellular rejection (ACR) is associated with donor-specific antibodies (DSA) development, chronic rejection, and allograft loss. However, accurate predictors of late ACR treatment response are lacking. ACR is primarily T-cell mediated, yet B cells and plasma cells (PC) also infiltrate the portal areas during late ACR. To test the hypothesis that the inflammatory milieu is associated with delayed response (DR) to rejection therapy, we performed a single-center retrospective case-control study of pediatric late liver ACR using multiparameter immunofluorescence for CD4, CD8, CD68, CD20, and CD138 to identify immune cell subpopulations.

METHODS

Pediatric liver transplant recipients transplanted at <17 years of age and treated for biopsy-proven late ACR between January 2014 and 2019 were stratified into rapid response (RR) and DR based on alanine aminotransferase (ALT) normalization within 30 days of diagnosis. All patients received IV methylprednisolone as an initial rejection treatment. Immunofluorescence was performed on archived formalin-fixed paraffin embedded (FFPE) liver biopsy tissue.

RESULTS

Liver biopsies from 60 episodes of late ACR in 54 patients were included in the analysis, of which 33 were DR (55%). Anti-thymocyte globulin was only required in the DR group. The frequency of liver-infiltrating CD20+ and CD8+ lymphocytes and the prevalence of autoantibodies were higher in the DR group. In univariate logistic regression analysis, serum gamma-glutamyl transpeptidase (GGT) level at diagnosis, but not ALT, Banff score or presence of DSA, predicted DR.

CONCLUSIONS

Higher serum GGT level, presence of autoantibodies, and increased CD8+ T-cell infiltration portends DR in late ACR treatment in children.

Effects of invivo CXCR4 Blockade and Proteasome Inhibition on Bone Marrow Plasma Cells in HLA-Sensitized Kidney Transplant Candidates

To date, plasma cell (PC)-targeted therapies have been limited by suboptimal PC depletion and antibody rebound. We hypothesized this is partly because of PC residence in protective bone marrow (BM) microenvironments. The purpose of this proof-of-concept study was to examine the effects of the CXCR4 antagonist, plerixafor, on PC BM residence; its safety profile (alone and in combination with a proteasome inhibitor, bortezomib); and the transcriptional effect on BMPCs in HLA-sensitized kidney transplant candidates. Participants were enrolled into 3 groups: group A (n = 4), plerixafor monotherapy; and groups B (n = 4) and C (n = 4), plerixafor and bortezomib combinations. CD34⁺ stem cell and PC levels increased in the blood after plerixafor treatment. PC recovery from BM aspirates varied depending on the dose of plerixafor and bortezomib. Single-cell RNA sequencing on BMPCs from 3 group C participants pretreatment and posttreatment revealed multiple populations of PCs, with a posttreatment enrichment of oxidative phosphorylation, proteasome assembly, cytoplasmic translation, and autophagy-related genes. Murine studies demonstrated dually inhibiting the proteasome and autophagy resulted in greater BMPC death than did monotherapies. In conclusion, this pilot study revealed anticipated effects of combined plerixafor and bortezomib on BMPCs, an acceptable safety profile, and suggests the potential for autophagy inhibitors in desensitization regimens.

Single cell transcriptomic analysis of renal allograft rejection reveals novel insights into intragraft TCR clonality

Bulk analysis of renal allograft biopsies (rBx) identified RNA transcripts associated with acute cellular rejection (ACR); however, these lacked cellular context critical to mechanistic understanding. We performed combined single cell RNA transcriptomic and TCRα/β sequencing on rBx from patients with ACR under differing immunosuppression (IS): tacrolimus, iscalimab, and belatacept. TCR analysis revealed a highly restricted CD8 ⁺ T cell clonal expansion (CD8 _EXP ), independent of HLA mismatch or IS type. Subcloning of TCRα/β cDNAs from CD8 _EXP into Jurkat76 cells (TCR ^-/- ) conferred alloreactivity by mixed lymphocyte reaction. scRNAseq analysis of CD8 _EXP revealed effector, memory, and exhausted phenotypes that were influenced by IS type. Successful anti-rejection treatment decreased, but did not eliminate, CD8 _EXP , while CD8 _EXP were maintained during treatment-refractory rejection. Finally, most rBx-derived CD8 _EXP were also observed in matching urine samples. Overall, our data define the clonal CD8 ⁺ T cell response to ACR, providing novel insights to improve detection, assessment, and treatment of rejection.

Analysis of Cross-sectional and Longitudinal HLA and Anti-viral Responses After COVID Infection in Renal Allograft Recipients: Differences and Correlates

BACKGROUND

Characterization of anti-HLA versus anti-severe acute respiratory syndrome coronavirus 2 (anti-SARS-CoV-2) immune globulin isotypes in organ transplant recipients after coronavirus disease 2019 (COVID-19) infection has not been reported. We aimed to determine changes in anti-HLA antibodies in renal transplant patients with COVID-19 and compare the immunoglobulin and epitope-binding pattern versus anti-SARS-CoV-2 antibodies.

METHODS

This is a cross-sectional study of 46 kidney transplant recipients including 21 with longitudinal sampling. Using a semi-quantitative multiplex assay, we determined immunoglobulin (Ig) M, IgA, IgG, and IgG1-2-3-4 antibodies against Class I and Class II HLA, and 5 SARS-CoV-2 epitopes including the nucleocapsid protein and multiple regions of the spike protein.

RESULTS

Fourteen of 46 (30%) patients had donor-specific anti-HLA antibodies (donor-specific antibody [DSA]), 12 (26%) had non-DSA anti-HLA antibodies and 45 (98%) had anti-SARS-CoV-2 antibodies. Most DSAs targeted HLA-DQ (71%), with a dominant IgG isotype and IgG1 subtype prevalence (93%), and/or IgG3 (64%), followed by IgG2 (36%). Comparatively, there was a higher prevalence of IgA (85% versus 14%, P = 0.0001) and IgM (87%, versus 36%, P = 0.001) in the anti-SARS-CoV-2 antibody profile, when compared to DSAs, respectively. Anti-SARS-CoV-2 antibody profile was characterized by increased prevalence of IgM and IgA, when compared to DSAs. The median calculated panel reactive antibody before COVID-19 diagnosis (24%) tended to decrease after COVID-19 diagnosis (10%) but it was not statistically significant ( P = 0.1).

CONCLUSIONS

Anti-HLA antibody strength and calculated panel reactive antibody in kidney transplant recipients after COVID-19 do not significantly increase after infection. Although the IgG isotype was the dominant form in both HLA and SARS-CoV-2 antigens, the alloimmune response had a low IgA pattern, whereas anti-SARS-CoV-2 antibodies were high IgA/IgM.

One-Year Outcomes of the Multi-Center StudY to Transplant Hepatitis C-InfeCted kidneys (MYTHIC) Trial

Introduction

Transplanting kidneys from hepatitis C virus (HCV) viremic donors into HCV-negative patients (HCV D-RNA-positive/R-negative) has evolved from experimental to “standard-of-care” at many centers. Nevertheless, most data derive from single centers and provide only short-term follow-up.

Methods

The Multicenter Study to Transplant Hepatitis C-Infected Kidneys (MYTHIC) study was a multicenter (7 sites) trial of HCV D-RNA-positive/R-negative kidney transplantation (KT) followed by 8 weeks of glecaprevir/pibrentasvir (G/P) initiated 2 to 5 days post-KT. Prespecified outcomes included probability of KT (vs. matched waitlist comparators) and 1-year safety outcomes, allograft function, and survival.

Results

Among 63 enrolled patients, 1-year cumulative incidence of KT was approximately 3.5-fold greater for the MYTHIC cohort versus 2055 matched United Network for Organ Sharing (UNOS) comparators who did not opt-in to receive a kidney from an HCV-viremic donor (68% vs. 19%, P < 0.0001). Of 30 HCV D-RNA-positive/R-negative KT recipients, all achieved HCV cure. None developed clinically significant liver disease or HCV-related kidney injury. Furthermore, 1-year survival was 93% and 1-year graft function was excellent (median creatinine 1.17; interquartile range [IQR]: 1.02–1.38 mg/dl). There were 4 cases of cytomegalovirus (CMV) disease among 10 CMV-negative patients transplanted with a kidney from an HCV-viremic/CMV-positive donor.

Conclusion

The 1-year findings from this multicenter trial suggest that opting-in for HCV-viremic KT offers can increase probability of KT with excellent 1-year outcomes. Trial Registration: NCT03781726

Delayed Kinetics of IgG, but Not IgA, Antispike Antibodies in Transplant Recipients following SARS-CoV-2 Infection

BACKGROUND

Kidney transplant recipients are at increased risk of severe outcomes during COVID-19. Antibodies against the virus are thought to offer protection, but a thorough characterization of anti-SARS-CoV-2 immune globulin isotypes in kidney transplant recipients following SARS-CoV-2 infection has not been reported.

METHODS

We performed a cross-sectional study of 49 kidney transplant recipients and 42 immunocompetent controls at early (≤14 days) or late (>14 days) time points after documented SARS-CoV-2 infection. Using a validated semiquantitative Luminex-based multiplex assay, we determined the abundances of IgM, IgG, IgG1-4, and IgA antibodies against five distinct viral epitopes.

RESULTS

Kidney transplant recipients showed lower levels of total IgG antitrimeric spike (S), S1, S2, and receptor binding domain (RBD) but not nucleocapsid (NC) at early versus late time points after SARS-CoV-2 infection. Early levels of IgG antispike protein epitopes were also lower than in immunocompetent controls. Anti-SARS-CoV-2 antibodies were predominantly IgG1 and IgG3, with modest class switching to IgG2 or IgG4 in either cohort. Later levels of IgG antispike, S1, S2, RBD, and NC did not significantly differ between cohorts. There was no significant difference in the kinetics of either IgM or IgA antispike, S1, RBD, or S2 on the basis of timing after diagnosis or transplant status.

CONCLUSIONS

Kidney transplant recipients mount early anti-SARS-CoV-2 IgA and IgM responses, whereas IgG responses are delayed compared with immunocompetent individuals. These findings might explain the poor outcomes in transplant recipients with COVID-19.

PODCAST

This article contains a podcast at https://www.asn-online.org/media/podcast/JASN/2021_11_23_briggsgriffin112321.mp3.

Advanced Genomics-Based Approaches for Defining Allograft Rejection With Single Cell Resolution

Solid organ transplant recipients require long-term immunosuppression for prevention of rejection. Calcineurin inhibitor (CNI)-based immunosuppressive regimens have remained the primary means for immunosuppression for four decades now, yet little is known about their effects on graft resident and infiltrating immune cell populations. Similarly, the understanding of rejection biology under specific types of immunosuppression remains to be defined. Furthermore, development of innovative, rationally designed targeted therapeutics for mitigating or preventing rejection requires a fundamental understanding of the immunobiology that underlies the rejection process. The established use of microarray technologies in transplantation has provided great insight into gene transcripts associated with allograft rejection but does not characterize rejection on a single cell level. Therefore, the development of novel genomics tools, such as single cell sequencing techniques, combined with powerful bioinformatics approaches, has enabled characterization of immune processes at the single cell level. This can provide profound insights into the rejection process, including identification of resident and infiltrating cell transcriptomes, cell-cell interactions, and T cell receptor α/β repertoires. In this review, we discuss genomic analysis techniques, including microarray, bulk RNAseq (bulkSeq), single-cell RNAseq (scRNAseq), and spatial transcriptomic (ST) techniques, including considerations of their benefits and limitations. Further, other techniques, such as chromatin analysis via assay for transposase-accessible chromatin sequencing (ATACseq), bioinformatic regulatory network analyses, and protein-based approaches are also examined. Application of these tools will play a crucial role in redefining transplant rejection with single cell resolution and likely aid in the development of future immunomodulatory therapies in solid organ transplantation.

Seroprevalence of SARS-CoV-2 infection in Cincinnati Ohio USA from August to December 2020

The world is currently in a pandemic of COVID-19 (Coronavirus disease-2019) caused by a novel positive-sense, single-stranded RNA β-coronavirus referred to as SARS-CoV-2. Here we investigated rates of SARS-CoV-2 infection in the greater Cincinnati, Ohio, USA metropolitan area from August 13 to December 8, 2020, just prior to initiation of the national vaccination program. Examination of 9,550 adult blood donor volunteers for serum IgG antibody positivity against the SARS-CoV-2 Spike protein showed an overall prevalence of 8.40%, measured as 7.56% in the first 58 days and 9.24% in the last 58 days, and 12.86% in December 2020, which we extrapolated to ~20% as of March, 2021. Males and females showed similar rates of past infection, and rates among Hispanic or Latinos, African Americans and Whites were also investigated. Donors under 30 years of age had the highest rates of past infection, while those over 60 had the lowest. Geographic analysis showed higher rates of infectivity on the West side of Cincinnati compared with the East side (split by I-75) and the lowest rates in the adjoining region of Kentucky (across the Ohio river). These results in regional seroprevalence will help inform efforts to best achieve herd immunity in conjunction with the national vaccination campaign.

Plasma cell biology: Foundations for targeted therapeutic development in transplantation

Solid organ transplantation is a life-saving procedure for patients with end-stage organ disease. Over the past 70 years, tremendous progress has been made in solid organ transplantation, particularly in T-cell-targeted immunosuppression and organ allocation systems. However, humoral alloimmune responses remain a major challenge to progress. Patients with preexisting antibodies to human leukocyte antigen (HLA) are at significant disadvantages in regard to receiving a well-matched organ, moreover, those who develop anti-HLA antibodies after transplantation face a significant foreshortening of renal allograft survival. Historical therapies to desensitize patients prior to transplantation or to treat posttransplant AMR have had limited effectiveness, likely because they do not significantly reduce antibody levels, as plasma cells, the source of antibody production, remain largely unaffected. Herein, we will discuss the significance of plasma cells in transplantation, aspects of their biology as potential therapeutic targets, clinical challenges in developing strategies to target plasma cells in transplantation, and lastly, novel approaches that have potential to advance the field.

Belatacept for Simultaneous Calcineurin Inhibitor and Chronic Corticosteroid Immunosuppression Avoidance

Immunosuppressive therapy in kidney transplantation is associated with numerous toxicities. CD28-mediated T cell costimulation blockade using belatacept may reduce long-term nephrotoxicity, compared with calcineurin inhibitor-based immunosuppression. The efficacy and safety of simultaneous calcineurin inhibitor avoidance and rapid steroid withdrawal were tested in a randomized, prospective, multi-center study. Methods All kidney transplants were performed using rapid steroid withdrawal immunosuppression. Recipients were randomized to 1:1:1 to receive belatacept with alemtuzumab induction, belatacept with rabbit antithymocyte globulin (rATG) induction, or tacrolimus with rATG induction. The composite endpoint consisted of death, kidney allograft loss, or an MDRD calculated eGFR of <45 ml/min/1.73m² at 2 years. Results The composite endpoint was observed for 11/107 (10%) participants assigned to belatacept/alemtuzumab, 13/104 (13%) assigned to belatacept /rATG, and 21/105 (21%) assigned to tacrolimus/rATG (belatacept/alemtuzumab vs tacrolimus/rATG p = 0.99: belatacept/rATG vs tacrolimus/rATG p = 0.66). Patient and graft survival rates were similar between all groups. eGFR <45 ml/min/1.73m² was observed for 9/107 (8%) participants assigned to belatacept/alemtuzuab, 8/104 (8%) participants assigned to belatacept/rATG, and 20/105 (19%) participants assigned to tacrolimus/rATG (p<0.05 for each belatacept group vs tacrolimus/rATG). Biopsy-proven acute rejection was observed for 20/107 (19%) participants assigned to belatacept/alemtuzuab, 26/104 (25%) participants assigned to belatacept/rATG, and 7/105 (7%) participants assigned to tacrolimus/rATG (belatacept/alemtuzumab vs tacrolimus/rATG p = 0.006: belatacept/rATG vs tacrolimus/rATG p < 0.001). Gastrointestinal and neurologic adverse events were less frequent with belatacept versus calcineurin based immunosuppression. Conclusions Overall two-year outcomes were similar comparing maintenance immunosuppression based on belatacept versus tacrolimus, each protocol with rapid steroid withdrawal. The incidence of eGFR <45 ml/min/1.73m² was significantly lower but the incidence of biopsy proven acute rejection significantly higher with belatacept compared with tacrolimus.

Incorporating Patients' Values and Preferences Into Decision Making About Transplantation of HCV-Naïve Recipients With Kidneys From HCV-Viremic Donors: A Feasibility Study

Introduction. While use of (hepatitis C virus) HCV-viremic kidneys may result in net benefit for the average end-stage kidney disease (ESKD) patient awaiting transplantation, patients may have different values for ESKD-related health states. Thus, the best decision for any individual may be different depending on the balance of these factors. Our objective was to explore the feasibility of sampling health utilities from hemodialysis patients in order to perform patient-specific decision analyses considering various transplantation strategies. Study Design. We assessed utilities on a convenience sample of hemodialysis patients for health states including hemodialysis, and transplantation with either an HCV-uninfected kidney or an HCV-viremic kidney. We performed patient-specific decision analyses using each patient's age, race, gender, dialysis vintage, and utilities. We used a Markov state transition model considering strategies of continuing hemodialysis, transplantation with an HCV-unexposed kidney, and transplantation with an HCV-viremic kidney and HCV treatment. We interviewed 63 ESKD patients from four dialysis centers (Dialysis Clinic Inc., DCI) in the Cincinnati metropolitan area. Results. Utilities for ESKD-related health states varied widely from patient to patient. Mean values were highest for -transplantation with an HCV-uninfected kidney (0.89, SD: 0.18), and were 0.825 (SD: 0.231) and 0.755 (SD: 0.282), respectively, for hemodialysis and transplantation with an HCV-viremic kidney. Patient-specific decision analyses indicated 37 (59%) of the 63 ESKD patients in the cohort would have a net gain in quality-adjusted life years from transplantation of an HCV-viremic kidney, while 26 would have a net loss. Conclusions. It is feasible to gather dialysis patients' health state utilities and perform personalized decision analyses. This approach could be used in the future to guide shared decision-making discussions about transplantation strategies for ESKD patients.

Optimization of de novo belatacept-based immunosuppression administered to renal transplant recipients

Kidney transplant recipients administered belatacept-based maintenance immunosuppression present with a more favorable metabolic profile, reduced incidence of de novo donor-specific antibodies (DSAs), and improved renal function and long-term patient/graft survival relative to individuals receiving calcineurin inhibitor (CNI)-based immunosuppression. However, the rates and severity of acute rejection (AR) are greater with the approved belatacept-based regimen than with CNI-based immunosuppression. Although these early co-stimulation blockade-resistant rejections are typically steroid sensitive, the higher rate of cellular AR has led many transplant centers to adopt immunosuppressive regimens that differ from the approved label. This article summarizes the available data on these alternative de novo belatacept-based maintenance regimens. Steroid-sparing, belatacept-based immunosuppression (following T cell-depleting induction therapy) has been shown to yield AR rates comparable to those seen with CNI-based regimens. Concomitant treatment with belatacept plus a mammalian target of rapamycin inhibitor (mTORi; sirolimus or everolimus) has yielded AR rates ranging from 0 to 4%. Because the optimal induction agent and number of induction doses; blood levels of mTORi; and dose, duration, and use of corticosteroids have yet to be determined, larger prospective clinical trials are needed to establish the optimal alternative belatacept-based regimen for minimizing early cellular AR occurrence.

Early Corticosteroid Cessation vs Long-term Corticosteroid Therapy in Kidney Transplant Recipients: Long-term Outcomes of a Randomized Clinical Trial

Importance

The complications of corticosteroids make the inclusion of these drugs in immunosuppressive protocols for kidney transplant patients undesirable. However, cessation of corticosteroids is associated with a higher risk of short-term rejection, and the long-term outcomes of patients withdrawn from corticosteroids remain uncertain.

Objective

To compare long-term kidney transplant outcomes of patients randomized to continue or withdraw corticosteroids.

Design, Setting, and Participants

This prospective multicenter randomized double-blind placebo-controlled trial was conducted between November 1999 and December 2002 with linkage to a mandatory national registry with validated outcome ascertainment until June 8, 2018. The study included 28 kidney transplant centers in the United States, including 386 low- to moderate-immune risk adult recipients of a living or deceased donor kidney transplant without delayed graft function or short-term rejection in the first week after transplant. Analyses were intention to treat. Analysis began September 2018 and ended June 2019.

Interventions

Patients were randomized to receive tacrolimus and mycophenolate mofetil with or without corticosteroids 7 days after transplant.

Main Outcomes and Measures

Kidney allograft failure from any cause including death and allograft failure censored for patient death defined by the requirement for long-term dialysis or repeat transplant.

Results

Of 385 patients, 191 were assigned to withdraw from corticosteroids (mean [SD] age, 46.5 [12.1] years), and 194 patients were assigned to continued corticosteroids (mean [SD] age, 46.3 [12.6] years). The median (interquartile range) follow-up time was 15.8 (12.0-16.3) years after transplant. The adjusted hazard ratios of allograft failure from any cause including death was 0.83 (95% CI, 0.62-1.10; P = .19) and for allograft failure censored for patient death was 0.78 (95% CI, 0.52-1.19; P = .25) and did not differ between the patients assigned to withdraw from corticosteroids vs assigned to continued corticosteroids. Results were consistent in a per-protocol analysis among 223 patients who continued the trial-assigned treatment of corticosteroid withdrawal (n = 114) or corticosteroids (n = 109) through at least 5 years after transplant. The outcomes of trial participants in either treatment group did not differ from similarly treated contemporary registry patients who met trial eligibility criteria and were treated with the same immunosuppressive drugs.

Conclusions and Relevance

Long-term corticosteroids may not be necessary as part of a calcineurin-based multiple drug immunosuppressive regimen in low- to moderate-immune risk kidney transplant recipients.

Preexisting melanoma and hematological malignancies, prognosis, and timing to solid organ transplantation: A consensus expert opinion statement

Patients undergoing evaluation for solid organ transplantation (SOT) frequently have a history of malignancy. Only patients with treated cancer are considered for SOT but the benefits of transplantation need to be balanced against the risk of tumor recurrence, taking into consideration the potential effects of immunosuppression. Prior guidelines on timing to transplant in patients with a prior treated malignancy do not account for current staging, disease biology, or advances in cancer treatments. To update these recommendations, the American Society of Transplantation (AST) facilitated a consensus workshop to comprehensively review contemporary literature regarding cancer therapies, cancer stage specific prognosis, the kinetics of cancer recurrence, as well as the limited data on the effects of immunosuppression on cancer-specific outcomes. This document contains prognosis, treatment, and transplant recommendations for melanoma and hematological malignancies. Given the limited data regarding the risk of cancer recurrence in transplant recipients, the goal of the AST-sponsored conference and the consensus documents produced are to provide expert opinion recommendations that help in the evaluation of patients with a history of a pretransplant malignancy for transplant candidacy.

Pretransplant solid organ malignancy and organ transplant candidacy: A consensus expert opinion statement

Patients undergoing evaluation for solid organ transplantation (SOT) often have a history of malignancy. Although the cancer has been treated in these patients, the benefits of transplantation need to be balanced against the risk of tumor recurrence, especially in the setting of immunosuppression. Prior guidelines of when to transplant patients with a prior treated malignancy do not take in to account current staging, disease biology, or advances in cancer treatments. To develop contemporary recommendations, the American Society of Transplantation held a consensus workshop to perform a comprehensive review of current literature regarding cancer therapies, cancer stage-specific prognosis, the kinetics of cancer recurrence, and the limited data on the effects of immunosuppression on cancer-specific outcomes. This document contains prognosis based on contemporary treatment and transplant recommendations for breast, colorectal, anal, urological, gynecological, and nonsmall cell lung cancers. This conference and consensus documents aim to provide recommendations to assist in the evaluation of patients for SOT given a history of a pretransplant malignancy.

Multicenter Study to Transplant Hepatitis C-Infected Kidneys (MYTHIC): An Open-Label Study of Combined Glecaprevir and Pibrentasvir to Treat Recipients of Transplanted Kidneys from Deceased Donors with Hepatitis C Virus Infection

BACKGROUND

Single-center trials and retrospective case series have reported promising outcomes using kidneys from donors with hepatitis C virus (HCV) infection. However, multicenter trials are needed to determine if those findings are generalizable.

METHODS

We conducted a prospective trial at seven centers to transplant 30 kidneys from deceased donors with HCV viremia into HCV-uninfected recipients, followed by 8 weeks of once-daily coformulated glecaprevir and pibrentasvir, targeted to start 3 days posttransplant. Key outcomes included sustained virologic response (undetectable HCV RNA 12 weeks after completing treatment with glecaprevir and pibrentasvir), adverse events, and allograft function.

RESULTS

We screened 76 patients and enrolled 63 patients, of whom 30 underwent kidney transplantation from an HCV-viremic deceased donor (median kidney donor profile index, 53%) in May 2019 through October 2019. The median time between consent and transplantation of a kidney from an HCV-viremic donor was 6.3 weeks. All 30 recipients achieved a sustained virologic response. One recipient died of complications of sepsis 4 months after achieving a sustained virologic response. No severe adverse events in any patient were deemed likely related to HCV infection or treatment with glecaprevir and pibrentasvir. Three recipients developed acute cellular rejection, which was borderline in one case. Three recipients developed polyomavirus (BK) viremia near or >10,000 copies/ml that resolved after reduction of immunosuppression. All recipients had good allograft function, with a median creatinine of 1.2 mg/dl and median eGFR of 57 ml/min per 1.73 m² at 6 months.

CONCLUSIONS

Our multicenter trial demonstrated safety and efficacy of transplantation of 30 HCV-viremic kidneys into HCV-negative recipients, followed by early initiation of an 8-week regimen of glecaprevir and pibrentasvir.

Plasma cell targeting to prevent antibody-mediated rejection

Plasma cells (PCs) are the major source of pathogenic allo- and autoantibodies and have historically demonstrated resistance to therapeutic targeting. However, significant recent clinical progress has been made with the use of second-generation proteasome inhibitors (PIs). PIs provide efficient elimination of plasmablast-mediated humoral responses; however, long-lived bone marrow (BM) resident PCs (LLPCs) demonstrate therapeutic resistance, particularly to first-generation PIs. In addition, durability of antibody (Ab) reduction still requires improvement. More recent clinical trials have focused on conditions mediated by LLPCs and have included mechanistic studies of LLPCs from PI-treated patients. A recent clinical trial of carfilzomib (a second-generation irreversible PI) demonstrated improved efficacy in eliminating BM PCs and reducing anti-HLA Abs in chronically HLA-sensitized patients; however, Ab rebound was observed over several weeks to months following PI therapy. Importantly, recent murine studies have provided substantial insights into PC biology, thereby further enhancing our understanding of PC populations. It is now clear that BMPC populations, where LLPCs are thought to primarily reside, are heterogeneous and have distinct gene expression, metabolic, and survival signatures that enable identification and characterization of PC subsets. This review highlights recent advances in PC biology and clinical trials in transplant populations.

Belatacept-based immunosuppression with simultaneous calcineurin inhibitor avoidance and early corticosteroid withdrawal: A prospective, randomized multicenter trial

Simultaneous calcineurin inhibitor avoidance (CNIA) and early corticosteroid withdrawal (ESW) have not been achieved primarily due to excessive acute rejection. This trial compared 2 belatacept-based CNIA/ESW regimens with a tacrolimus-based ESW regimen. Kidney transplant recipients were randomized to receive alemtuzumab/belatacept, rabbit anti-thymocyte globulin (rATG)/belatacept, or rATG/tacrolimus. The combinatorial primary endpoint consisted of patient death, renal allograft loss, or a Modification of Diet in Renal Disease-calculated eGFR of <45 mL/min/1.73 m² at 12 months. Results are reported by treatment group (alemtuzumab/belatacept, rATG/belatacept, and rATG/tacrolimus). Superiority was not observed at 1 year for the primary endpoint (9/107 [8.4%], 15/104 [14.4%], and 14/105 [13.3%], respectively; P = NS) for either belatacept-based regimen. Differences were not observed for secondary endpoints (death, death-censored graft loss, or estimated glomerular filtration rates < 45 mL/min/1.73 m² ). Differences were observed in biopsy-proved acute cellular rejection (10.3%, 18.3%, and 1.9%, respectively) (P < .001), but not in antibody-mediated rejection, mixed acute rejection, or de novo donor-specific anti-HLA antibodies. Neurologic and electrolyte abnormality adverse events were less frequent under belatacept. Belatacept-based CNIA/ESW regimens did not prove to be superior for the primary or secondary endpoints. Belatacept-treated patients demonstrated an increase in biopsy-proved acute cellular rejection and reduced neurologic and metabolic adverse events. These results demonstrate that simultaneous CNIA/ESW is feasible without excessive acute rejection.

Cost-effectiveness of Using Kidneys From HCV-Viremic Donors for Transplantation Into HCV-Uninfected Recipients

RATIONALE & OBJECTIVE

Less than 4% of patients with kidney failure receive kidney transplants. Although discard rates of hepatitis C virus (HCV)-viremic kidneys are declining, ~39% of HCV-viremic kidneys donated between 2018 and 2019 were discarded. Highly effective antiviral agents are now available to treat chronic HCV infection. Thus, our objective was to examine the cost-effectiveness of transplanting kidneys from HCV-viremic donors into HCV-uninfected recipients.

STUDY DESIGN

Markov state transition decision model. Data sources include Medline search results, bibliographies from relevant English language articles, Scientific Registry of Transplant Recipients, and the US Renal Data System.

SETTING & POPULATION

US patients receiving maintenance hemodialysis who are on kidney transplant waiting lists.

INTERVENTION(S)

Transplantation with an HCV-unexposed kidney versus transplantation with an HCV-viremic kidney and HCV treatment.

OUTCOMES

Effectiveness measured in quality-adjusted life-years and costs measured in 2018 US dollars.

MODEL, PERSPECTIVE, AND TIMEFRAME

We used a health care system perspective with a lifelong time horizon.

RESULTS

In the base-case analysis, transplantation with an HCV-viremic kidney was more effective and less costly than transplantation with an HCV-unexposed kidney because of the longer waiting times for HCV-unexposed kidneys, the substantial excess mortality risk while receiving dialysis, and the high efficacy of direct-acting antiviral agents for HCV infection. Transplantation with an HCV-viremic kidney was also preferred in sensitivity analyses of multiple model parameters. The strategy remained cost-effective unless waiting list time for an HCV-viremic kidney exceeded 3.1 years compared with the base-case value of 1.56 year.

LIMITATIONS

Estimates of waiting times for patients willing to accept an HCV-viremic kidney were based on data for patients who received HCV-viremic kidney transplants.

CONCLUSIONS

Transplanting kidneys from HCV-viremic donors into HCV-uninfected recipients increased quality-adjusted life expectancy and reduced costs compared with a strategy of transplanting kidneys from HCV-unexposed donors.

Long-term outcomes in patients with obesity and renal disease after sleeve gastrectomy

Morbid obesity is a barrier to kidney transplant in patients with end-stage renal disease (ESRD). Laparoscopic sleeve gastrectomy (SG) is an increasingly considered intervention, but the safety and long-term outcomes are uncertain. We reviewed prospectively collected data on patients with ESRD and chronic kidney disease (CKD) undergoing SG from 2011 to 2018. There were 198 patients with ESRD and 45 patients with CKD (stages 1-4) who met National Institutes of Health guidelines for bariatric surgery and underwent SG; 72% and 48% achieved a body mass index of ≤ 40 and ≤ 35 kg/m² , respectively. The mean percentages of total weight loss and excess weight loss were 18.9 ± 10.8% and 38.2 ± 20.3%, respectively. SG reduced hypertension (85.8% vs 52.1%), decreased antihypertensive medication use (1.6 vs 1.0) (P < .01 each), and reduced incidence of diabetes (59.6% vs 32.5%, P < .01). Of the 71 patients with ESRD who achieved a body mass index of ≤ 40 kg/m² , 45 were waitlisted and received a kidney transplant, whereas 10 remain on the waitlist. Mortality rate after SG was 1.8 per 100 patient-years, compared with 7.3 for non-SG. Patients with stage 3a or 3b CKD exhibited improved glomerular filtration rate (43.5 vs 58.4 mL/min, P = .01). In conclusion, SG safely improves transplant candidacy while providing significant, sustainable effects on weight loss, reducing medical comorbidities, and possibly improving renal function in stage 3 patients.

A prospective, iterative, adaptive trial of carfilzomib-based desensitization

Proteasome inhibitor-based strategies hold promise in transplant but have yielded varying results. Carfilzomib, a second-generation proteasome inhibitor, may possess advantages over bortezomib, the first-generation proteasome inhibitors. The purpose of this study was to evaluate the safety, toxicity, and preliminary efficacy of carfilzomib in highly HLA-sensitized kidney transplant candidates. Renal transplant candidates received escalating doses of carfilzomib followed by plasmapheresis (group A) or an identical regimen with additional plasmapheresis once weekly before carfilzomib dosing. Thirteen participants received carfilzomib, which was well tolerated with most adverse events classified as low grade. The safety profile was similar to bortezomib desensitization; however, neurotoxicity was not observed with carfilzomib. Toxicity resulted in permanent dose reduction in 1 participant but caused no withdrawals or deaths. HLA antibodies were substantially reduced with carfilzomib alone, and median maximal immunodominant antibody reduction was 72.8% (69.8% for group A, P = .031, 80.1% for group B, P = .938). After depletion, rebound occurred rapidly and antibody levels returned to baseline between days 81 and 141. Bone marrow studies revealed that approximately 69.2% of plasma cells were depleted after carfilzomib monotherapy. Carfilzomib monotherapy-based desensitization provides an acceptable safety and toxicity profile while leading to significant bone marrow plasma cell depletion and anti-HLA antibody reduction.

Safety, pharmacokinetics, and pharmacodynamic activity of obinutuzumab, a type 2 anti-CD20 monoclonal antibody for the desensitization of candidates for renal transplant

The limited effectiveness of rituximab plus intravenous immunoglobulin (IVIG) in desensitization may be due to incomplete B cell depletion. Obinutuzumab is a type 2 anti-CD20 antibody that induces increased B cell depletion relative to rituximab and may therefore be more effective for desensitization. This open-label phase 1b study assessed the safety, pharmacokinetics, and pharmacodynamics of obinutuzumab in highly sensitized patients with end-stage renal disease. Patients received 1 (day 1, n = 5) or 2 (days 1 and 15; n = 20) infusions of 1000-mg obinutuzumab followed by 2 doses of IVIG on days 22 and 43. Eleven patients received additional obinutuzumab doses at the time of transplant and/or at week 24. The median follow-up duration was 9.4 months. Obinutuzumab was well tolerated, and most adverse events were grade 1-2 in severity. There were 11 serious adverse events (SAEs) in 9 patients (36%); 10 of these SAEs were infections and 4 occurred after kidney transplant. Obinutuzumab plus IVIG resulted in profound peripheral B cell depletion and appeared to reduce B cells in retroperitoneal lymph nodes. Reductions in anti-HLA antibodies, number of unacceptable antigens, and the calculated panel reactive antibody score as centrally assessed using single-antigen bead assay were limited and not clinically meaningful for most patients (NCT02586051).

Clinical Implications of Donor Warm and Cold Ischemia Time in Donor After Circulatory Death Liver Transplantation

The use of donation after circulatory death (DCD) liver allografts has been constrained by limitations in the duration of donor warm ischemia time (DWIT), donor agonal time (DAT), and cold ischemia time (CIT). The purpose of this study is to assess the impact of longer DWIT, DAT, and CIT on graft survival and other outcomes in DCD liver transplants. The Scientific Registry of Transplant Recipients was queried for adult liver transplants from DCD donors between 2009 and 2015. Donor, recipient, and center variables were included in the analysis. During the study period, 2107 patients underwent liver transplant with DCD allografts. In most patients, DWIT and DAT were <30 minutes. DWIT was <30 minutes in 1804 donors, between 30 and 40 minutes in 248, and >40 minutes in 37. There was no difference in graft survival, duration of posttransplant hospital length of stay, and readmission rate between DCD liver transplants from donors with DWIT <30 minutes and DWIT between 30 and 40 minutes. Similar outcomes were noted for DAT. In the multivariate analysis, DAT and DWIT were not associated with graft loss. The predictors associated with graft loss were donor age, donor sharing, CIT, recipient admission to the intensive care unit, recipient ventilator dependence, Model for End-Stage Liver Disease score, and low-volume transplant centers. Any CIT cutoff >4 hours was associated with increased risk for graft loss. Longer CIT was also associated with a longer posttransplant hospital stay, higher rate of primary nonfunction, and hyperbilirubinemia. In conclusion, slightly longer DAT and DWIT (up to 40 minutes) were not associated with graft loss, longer posttransplant hospitalization, or hospital readmissions, whereas longer CIT was associated with worse outcomes after DCD liver transplants.

Rabbit anti-thymocyte globulin for the prevention of acute rejection in kidney transplantation

This report describes the results of 2 international randomized trials (total of 508 kidney transplant recipients). The primary objective was to assess the noninferiority of rabbit anti-thymocyte globulin (rATG, Thymoglobulin^® ) versus interleukin-2 receptor antagonists (IL2RAs) for the quadruple endpoint (treatment failure defined as biopsy-proven acute rejection, graft loss, death, or loss to follow-up) to serve as the pivotal data for United States (US) regulatory approval of rATG. The pooled analysis provided an incidence of treatment failure of 25.1% in the rATG and 36.0% in the IL2RA treatment groups, an absolute difference of -10.9% (95% confidence interval [CI] -18.8% to -2.9%) supporting noninferiority (noninferiority margin was 10%) and superiority of rATG to IL2RA. In a meta-analysis of 7 trials comparing rATG with an IL2RA, the difference in the proportion of patients with BPAR at 12 months was -4.8% (95% CI -8.6% to -0.9%) in favor of rATG. In conclusion, a rigorous reanalysis of patient-level data from 2 prior randomized, controlled trials comparing rATG versus IL-2R monoclonal antibodies provided support for regulatory approval for rATG for induction therapy in renal transplant, making it the first T cell-depleting therapy approved for the prophylaxis of acute rejection in patients receiving a kidney transplant in the United States.

The immune cell landscape in kidneys of patients with lupus nephritis

Lupus nephritis is a potentially fatal autoimmune disease for which the current treatment is ineffective and often toxic. To develop mechanistic hypotheses of disease, we analyzed kidney samples from patients with lupus nephritis and from healthy control subjects using single-cell RNA sequencing. Our analysis revealed 21 subsets of leukocytes active in disease, including multiple populations of myeloid cells, T cells, natural killer cells and B cells that demonstrated both pro-inflammatory responses and inflammation-resolving responses. We found evidence of local activation of B cells correlated with an age-associated B-cell signature and evidence of progressive stages of monocyte differentiation within the kidney. A clear interferon response was observed in most cells. Two chemokine receptors, CXCR4 and CX3CR1, were broadly expressed, implying a potentially central role in cell trafficking. Gene expression of immune cells in urine and kidney was highly correlated, which would suggest that urine might serve as a surrogate for kidney biopsies.

Assessment of tacrolimus intrapatient variability in stable adherent transplant recipients: Establishing baseline values

The purpose of this study was to determine the intrapatient (within the same patient) variability of tacrolimus in adherent patients. Daily tacrolimus trough levels were obtained at home using dried blood spot technology in kidney and liver transplant recipients. Patients were randomized to receive 3 formulations of tacrolimus, each for two 1-week periods. Adherence was monitored by patient diary, pill counts, and use of the Medication Event Monitoring System (MEMS). Variability was quantified as the coefficient of variation (CV). Comparison of CV between groups was by independent t test or one-way ANOVA as appropriate. The population was found to be adherent with a rate of 99.9% with a mean interval between the evening and morning dose of tacrolimus of 11.86 hours. The median CV for the entire population was 15.2% (range 4.8%-110%). There were no differences in CV by allograft type or tacrolimus formulation. The multivariate analysis did not identify any demographic characteristics associated with a CV > 30%. In a highly adherent population, tacrolimus did not display high intrapatient variability. Given the association between IPV and poor allograft outcomes, future studies are needed to quantitate the influence of adherence and establish target IPV goals.

Bariatric surgery prior to living donor nephrectomy: a solution to expand the living donor kidney pool - a retrospective study

Most transplant centers decline morbidly obese people for living kidney donation. Their inclusion in the living donor pool after weight loss and reversal of comorbidities by bariatric surgery could reverse the downward living donation trend. We investigated whether bariatric surgery in the morbidly obese altered their candidacy for donation, complicated their subsequent donor nephrectomy, and impacted their early postoperative outcomes in a series of 22 donors who had bariatric surgery 0.7-22 years prior to laparoscopic living donor nephrectomy. Eighteen would have been excluded from donation prior to bariatric surgery based on a body mass index (BMI) > 40. Seventeen reached a BMI < 35 after bariatric surgery. One had hypertension that resolved after bariatric surgery. Prior bariatric surgery did not influence port placement and laterality of donor nephrectomy. None required open conversion or blood transfusion. In an exploratory comparison with 37 donors with a BMI 35-40, length of stay and warm ischemic time were shorter, blood loss and postoperative complications were similar, and operative time was longer. We therefore advocate the consideration of bariatric surgery in preparation for donation in morbidly obese people since it positively alters their candidacy without major impact on the subsequent living donor nephrectomy and early outcomes.

Impact of Induction Therapy on Circulating T Follicular Helper Cells and Subsequent Donor-Specific Antibody Formation After Kidney Transplant

Introduction

The cellular events that contribute to generation of donor-specific anti-HLA antibodies (DSA) post-kidney transplantation (KTx) are not well understood. Characterization of such mechanisms could allow tailoring of immunosuppression to benefit sensitized patients.

Methods

We prospectively monitored circulating T follicular helper (cT_FH) cells in KTx recipients who received T-cell depleting (thymoglobulin, n = 54) or T-cell nondepleting (basiliximab, n = 20) induction therapy from pre-KTx to 1 year post-KTx and assessed their phenotypic changes due to induction and DSA occurrence, in addition to healthy controls (n = 13), for a total of 307 blood samples.

Results

Before KTx, patients displayed comparable levels of resting, central memory cT_FH cells with similar polarization to those of healthy controls. Unlike basiliximab induction, thymoglobulin induction significantly depleted cT_FH cells, triggered lymphopenia-induced proliferation that skewed cT_FH cells toward increased Th1 polarization, effector memory, and elevated programmed cell death protein 1 (PD-1)^int/hi expression, resembling activated phenotypes. Regardless of induction, patients who developed DSA post-KTx, harbored pre-KTx donor-reactive memory interleukin (IL)-21⁺ cT_FH cells and showed higher % cT_FH and lower % of T regulatory (T_REG) cells post-KTx resulting in elevated cT_FH:T_REG ratio at DSA occurrence.

Conclusion

Induction therapy distinctly shapes cT_FH cell phenotype post-KTx. Monitoring cT_FH cells before and after KTx may help detect those patients prone to DSA generation post-KTx.

Transplanting Hepatitis C Virus-Infected Versus Uninfected Kidneys Into Hepatitis C Virus-Infected Recipients: A Cost-Effectiveness Analysis

BACKGROUND

Direct-acting antiviral agents are now available to treat chronic hepatitis C virus (HCV) infection in patients with end-stage renal disease (ESRD).

OBJECTIVE

To examine whether it is more cost-effective to transplant HCV-infected or HCV-uninfected kidneys into HCV-infected patients.

DESIGN

Markov state-transition decision model.

DATA SOURCES

MEDLINE searches and bibliographies from relevant English-language articles.

TARGET POPULATION

HCV-infected patients with ESRD receiving hemodialysis in the United States.

TIME HORIZON

Lifetime.

PERSPECTIVE

Health care system.

INTERVENTION

Transplant of an HCV-infected kidney followed by HCV treatment versus transplant of an HCV-uninfected kidney preceded by HCV treatment.

OUTCOME MEASURES

Effectiveness, measured in quality-adjusted life-years (QALYs), and costs, measured in 2017 U.S. dollars.

RESULTS OF BASE-CASE ANALYSIS

Transplant of an HCV-infected kidney followed by HCV treatment was more effective and less costly than transplant of an HCV-uninfected kidney preceded by HCV treatment, largely because of longer wait times for uninfected kidneys. A typical 57.8-year-old patient receiving hemodialysis would gain an average of 0.50 QALY at a lifetime cost savings of $41 591.

RESULTS OF SENSITIVITY ANALYSIS

Transplant of an HCV-infected kidney followed by HCV treatment continued to be preferred in sensitivity analyses of many model parameters. Transplant of an HCV-uninfected kidney preceded by HCV treatment was not preferred unless the additional wait time for an uninfected kidney was less than 161 days.

LIMITATION

The study did not consider the benefit of decreased HCV transmission from treating HCV-infected patients.

CONCLUSION

Transplanting HCV-infected kidneys into HCV-infected patients increased quality-adjusted life expectancy and reduced costs compared with transplanting HCV-uninfected kidneys into HCV-infected patients.

PRIMARY FUNDING SOURCE

Merck Sharp & Dohme and the National Center for Advancing Translational Sciences.

Complement-activating donor-specific anti-HLA antibodies and solid organ transplant survival: A systematic review and meta-analysis

BACKGROUND

Anti-human leukocyte antigen donor-specific antibodies (anti-HLA DSAs) are recognized as a major barrier to patients' access to organ transplantation and the major cause of graft failure. The capacity of circulating anti-HLA DSAs to activate complement has been suggested as a potential biomarker for optimizing graft allocation and improving the rate of successful transplantations.

METHODS AND FINDINGS

To address the clinical relevance of complement-activating anti-HLA DSAs across all solid organ transplant patients, we performed a meta-analysis of their association with transplant outcome through a systematic review, from inception to January 31, 2018. The primary outcome was allograft loss, and the secondary outcome was allograft rejection. A comprehensive search strategy was conducted through several databases (Medline, Embase, Cochrane, and Scopus). A total of 5,861 eligible citations were identified. A total of 37 studies were included in the meta-analysis. Studies reported on 7,936 patients, including kidney (n = 5,991), liver (n = 1,459), heart (n = 370), and lung recipients (n = 116). Solid organ transplant recipients with circulating complement-activating anti-HLA DSAs experienced an increased risk of allograft loss (pooled HR 3.09; 95% CI 2.55-3.74, P = 0.001; I2 = 29.3%), and allograft rejection (pooled HR 3.75; 95% CI: 2.05-6.87, P = 0.001; I2 = 69.8%) compared to patients without complement-activating anti-HLA DSAs. The association between circulating complement-activating anti-HLA DSAs and allograft failure was consistent across all subgroups and sensitivity analyses. Limitations of the study are the observational and retrospective design of almost all included studies, the higher proportion of kidney recipients compared to other solid organ transplant recipients, and the inclusion of fewer studies investigating allograft rejection.

CONCLUSIONS

In this study, we found that circulating complement-activating anti-HLA DSAs had a significant deleterious impact on solid organ transplant survival and risk of rejection. The detection of complement-activating anti-HLA DSAs may add value at an individual patient level for noninvasive biomarker-guided risk stratification.

TRIAL REGISTRATION

National Clinical Trial protocol ID: NCT03438058.

Laparoscopic sleeve gastrectomy improves renal transplant candidacy and posttransplant outcomes in morbidly obese patients

Morbid obesity is a barrier to kidney transplantation due to inferior outcomes, including higher rates of new-onset diabetes after transplantation (NODAT), delayed graft function (DGF), and graft failure. Laparoscopic sleeve gastrectomy (LSG) increases transplant eligibility by reducing BMI in kidney transplant candidates, but the effect of surgical weight loss on posttransplantation outcomes is unknown. Reviewing single-center medical records, we identified all patients who underwent LSG before kidney transplantation from 2011-2016 (n = 20). Post-LSG kidney recipients were compared with similar-BMI recipients who did not undergo LSG, using 2:1 direct matching for patient factors. McNemar's test and signed-rank test were used to compare groups. Among post-LSG patients, mean BMI ± standard deviation (SD) was 41.5 ± 4.4 kg/m² at initial encounter, which decreased to 32.3 ± 2.9 kg/m² prior to transplantation (P < .01). No complications, readmissions, or mortality occurred following LSG. After transplantation, one patient (5%) experienced DGF, and no patients experienced NODAT. Allograft and patient survival at 1-year posttransplantation was 100%. Compared with non-LSG patients, post-LSG recipients had lower rates of DGF (5% vs 20%) and renal dysfunction-related readmissions (10% vs 27.5%) (P < .05 each). Perioperative complications, allograft survival, and patient survival were similar between groups. These data suggest that morbidly obese patients with end-stage renal disease who undergo LSG to improve transplant candidacy, achieve excellent posttransplantation outcomes.

Bioequivalence between innovator and generic tacrolimus in liver and kidney transplant recipients: A randomized, crossover clinical trial

BACKGROUND

Although the generic drug approval process has a long-term successful track record, concerns remain for approval of narrow therapeutic index generic immunosuppressants, such as tacrolimus, in transplant recipients. Several professional transplant societies and publications have generated skepticism of the generic approval process. Three major areas of concern are that the pharmacokinetic properties of generic products and the innovator (that is, "brand") product in healthy volunteers may not reflect those in transplant recipients, bioequivalence between generic and innovator may not ensure bioequivalence between generics, and high-risk patients may have specific bioequivalence concerns. Such concerns have been fueled by anecdotal observations and retrospective and uncontrolled published studies, while well-designed, controlled prospective studies testing the validity of the regulatory bioequivalence testing approach for narrow therapeutic index immunosuppressants in transplant recipients have been lacking. Thus, the present study prospectively assesses bioequivalence between innovator tacrolimus and 2 generics in individuals with a kidney or liver transplant.

METHODS AND FINDINGS

From December 2013 through October 2014, a prospective, replicate dosing, partially blinded, randomized, 3-treatment, 6-period crossover bioequivalence study was conducted at the University of Cincinnati in individuals with a kidney (n = 35) or liver transplant (n = 36). Abbreviated New Drug Applications (ANDA) data that included manufacturing and healthy individual pharmacokinetic data for all generics were evaluated to select the 2 most disparate generics from innovator, and these were named Generic Hi and Generic Lo. During the 8-week study period, pharmacokinetic studies assessed the bioequivalence of Generic Hi and Generic Lo with the Innovator tacrolimus and with each other. Bioequivalence of the major tacrolimus metabolite was also assessed. All products fell within the US Food and Drug Administration (FDA) average bioequivalence (ABE) acceptance criteria of a 90% confidence interval contained within the confidence limits of 80.00% and 125.00%. Within-subject variability was similar for the area under the curve (AUC) (range 12.11-15.81) and the concentration maximum (Cmax) (range 17.96-24.72) for all products. The within-subject variability was utilized to calculate the scaled average bioequivalence (SCABE) 90% confidence interval. The calculated SCABE 90% confidence interval was 84.65%-118.13% and 80.00%-125.00% for AUC and Cmax, respectively. The more stringent SCABE acceptance criteria were met for all product comparisons for AUC and Cmax in both individuals with a kidney transplant and those with a liver transplant. European Medicines Agency (EMA) acceptance criteria for narrow therapeutic index drugs were also met, with the only exception being in the case of Brand versus Generic Lo, in which the upper limits of the 90% confidence intervals were 111.30% (kidney) and 112.12% (liver). These were only slightly above the upper EMA acceptance criteria limit for an AUC of 111.11%. SCABE criteria were also met for the major tacrolimus metabolite 13-O-desmethyl tacrolimus for AUC, but it failed the EMA criterion. No acute rejections, no differences in renal function in all individuals, and no differences in liver function were observed in individuals with a liver transplant using the Tukey honest significant difference (HSD) test for multiple comparisons. Fifty-two percent and 65% of all individuals with a kidney or liver transplant, respectively, reported an adverse event. The Exact McNemar test for paired categorical data with adjustments for multiple comparisons was used to compare adverse event rates among the products. No statistically significant differences among any pairs of products were found for any adverse event code or for adverse events overall. Limitations of this study include that the observations were made under strictly controlled conditions that did not allow for the impact of nonadherence or feeding on the possible pharmacokinetic differences. Generic Hi and Lo were selected based upon bioequivalence data in healthy volunteers because no pharmacokinetic data in recipients were available for all products. The safety data should be interpreted in light of the small number of participants and the short observation periods. Lastly, only the 1 mg tacrolimus strength was utilized in this study.

CONCLUSIONS

Using an innovative, controlled bioequivalence study design, we observed equivalence between tacrolimus innovator and 2 generic products as well as between 2 generic products in individuals after kidney or liver transplantation following current FDA bioequivalence metrics. These results support the position that bioequivalence for the narrow therapeutic index drug tacrolimus translates from healthy volunteers to individuals receiving a kidney or liver transplant and provides evidence that generic products that are bioequivalent with the innovator product are also bioequivalent to each other.

TRIAL REGISTRATION

ClinicalTrials.gov NCT01889758.

Contrast-Induced Nephropathy in Renal Transplant Recipients: A Single Center Experience

BACKGROUND

Contrast-induced nephropathy (CIN) in native kidneys is associated with a significant increase in mortality and morbidity. Data regarding CIN in renal allografts are limited, however. We retrospectively studied CIN in renal allografts at our institution: its incidence, risk factors, and effect on long-term outcomes including allograft loss and death.

METHODS

One hundred thirty-five renal transplant recipients undergoing 161 contrast-enhanced computed tomography (CT) scans or coronary angiograms (Cath) between years 2000 and 2014 were identified. Contrast agents were iso- or low osmolar. CIN was defined as a rise in serum creatinine (SCr) by >0.3 mg/dl or 25% from baseline within 4 days of contrast exposure. After excluding 85 contrast exposures where patients had no SCr within 4 days of contrast administration, 76 exposures (CT: n = 45; Cath: n = 31) in 50 eligible patients were analyzed. Risk factors assessed included demographics, comorbid conditions, type/volume of contrast agent used, IV fluids, N-acetylcysteine administration, and calcineurin inhibitor use. Bivariate and multivariable analyses were used to assess the risk of CIN.

RESULTS

Incidence of CIN was 13% following both, CT (6 out of 45) and Cath (4 out of 31). Significant bivariate predictors of CIN were IV fluid administration (p = 0.05), lower hemoglobin (p = 0.03), and lower albumin (p = 0.02). In a multivariable model, CIN was predicted by N-acetylcysteine (p = 0.03) and lower hemoglobin (p = 0.01). Calcineurin inhibitor use was not associated with CIN. At last follow-up, CIN did not affect allograft or patient survival.

CONCLUSION

CIN is common in kidney transplant recipients, and there is room for quality improvement with regards to careful renal function monitoring post-contrast exposure. In our study, N-acetylcysteine exposure and lower hemoglobin were associated with CIN. Calcineurin inhibitor use was not associated with CIN. Our sample size is small, however, and larger prospective studies of CIN in renal allografts are needed.

Pharmacokinetic and pharmacogenetic analysis of immunosuppressive agents after laparoscopic sleeve gastrectomy

BACKGROUND

Severe obesity has been shown to limit access to renal transplantation in patients with end-stage renal disease (ESRD). Laparoscopic sleeve gastrectomy (LSG) has been performed in the ESRD population to assist in achieving waitlist and transplant eligibility. Little is known about how LSG impacts the bioequivalence of tacrolimus products and immunosuppression pharmacokinetics.

METHODS

This was a prospective, open-label, single-dose, crossover, two-period pharmacokinetic (PK) study. The purpose of this study was to assess single-dose PK of immediate-release tacrolimus (IR-TAC), extended-release tacrolimus (ER-TAC), and mycophenolic acid (MPA) in adult ESRD patients post-LSG.

RESULTS

Twenty-three subjects were included in the 24-hour PK assessments. The ratio of geometric means between ER-TAC and IR-TAC was 103.5% (90% CI; 89.6%-119.6%) for AUC_0-24 and 92.5% (90% CI; 80.4%-106.4%) for C_max . PK parameters were similar between ER-TAC and IR-TAC, except for C_min (P=.004) and C_max (P=.04). MPA AUC_0-24 was similar when given with either ER-TAC or IR-TAC (P=.32). Patients expressing CYP3A5*1 genotypes had lower tacrolimus AUC_0-24 values vs those with CYP3A5*3/*3 (IR-TACP<.001; ER-TACP=.008). Genotype did not impact MPA PK.

CONCLUSION

Dose modification of immunosuppressants post-LSG may not be necessary aside from standard therapeutic drug monitoring.

Addressing the challenges of sleeve gastrectomy in end-stage renal disease: Analysis of 100 consecutive renal failure patients

BACKGROUND

While previous studies have demonstrated short-term efficacy of laparoscopic sleeve gastrectomy in candidates awaiting renal transplantation, the combination of morbid obesity and end-stage renal disease presents unique challenges to perioperative care. We demonstrate how increasing experience and the development of postoperative care guidelines can improve outcomes in this high-risk population.

METHODS

Single-center medical records were reviewed for renal transplantation candidates undergoing laparoscopic sleeve gastrectomy between 2011 and 2015 by a single surgeon. Postoperative care protocols were established and continually refined throughout the study period, including a multidisciplinary approach to inpatient management and hospital discharge planning. The first 100 laparoscopic sleeve gastrectomy patients were included and divided into 4 equal cohorts based on case sequence.

RESULTS

Compared with the first 25 patients undergoing laparoscopic sleeve gastrectomy, the last 25 patients had shorter operative times (97.8 ± 27.9 min vs 124.2 ± 33.6 min), lower estimated blood loss (6.6 ± 20.8 mL vs 34.0 ± 38.1 mL), and shorter hospital duration of stay (1.7 ± 2.1 days vs 2.9 ± 0.7 days) (P < .01 each). Readmission rates, complications, and 1-year mortality did not differ significantly.

CONCLUSION

Increasing experience and the development of clinical care guidelines in this high-risk population is associated with reduced health care resource utilization and improved perioperative outcomes.

Plasma-Derived C1 Esterase Inhibitor for Acute Antibody-Mediated Rejection Following Kidney Transplantation: Results of a Randomized Double-Blind Placebo-Controlled Pilot Study

Antibody-mediated rejection (AMR) is typically treated with plasmapheresis (PP) and intravenous immunoglobulin (standard of care; SOC); however, there is an unmet need for more effective therapy. We report a phase 2b, multicenter double-blind randomized placebo-controlled pilot study to evaluate the use of human plasma-derived C1 esterase inhibitor (C1 INH) as add-on therapy to SOC for AMR. Eighteen patients received 20 000 units of C1 INH or placebo (C1 INH n = 9, placebo n = 9) in divided doses every other day for 2 weeks. No discontinuations, graft losses, deaths, or study drug-related serious adverse events occurred. While the study's primary end point, a difference between groups in day 20 pathology or graft survival, was not achieved, the C1 INH group demonstrated a trend toward sustained improvement in renal function. Six-month biopsies performed in 14 subjects (C1 INH = 7, placebo = 7) showed no transplant glomerulopathy (TG) (PTC+cg≥1b) in the C1 INH group, whereas 3 of 7 placebo subjects had TG. Endogenous C1 INH measured before and after PP demonstrated decreased functional C1 INH serum concentration by 43.3% (p < 0.05) for both cohorts (C1 INH and placebo) associated with PP, although exogenous C1 INH-treated patients achieved supraphysiological levels throughout. This new finding suggests that C1 INH replacement may be useful in the treatment of AMR.