Tubuloreticular Inclusions in Renal Allografts Associate with Viral Infections and Donor-Specific Antibodies

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

Biomarkers of Immune Activation and Incident Kidney Failure With Replacement Therapy: Findings From the African American Study of Kidney Disease and Hypertension

RATIONALE & OBJECTIVE

Immune activation is fundamental to the pathogenesis of many kidney diseases. Innate immune molecules such as soluble urokinase-type plasminogen activator receptor (suPAR) have been linked to the incidence and progression of chronic kidney disease (CKD). Whether other biomarkers of immune activation are associated with incident kidney failure with replacement therapy (KFRT) in African Americans with nondiabetic kidney disease is unclear.

STUDY DESIGN

Prospective cohort.

SETTING & PARTICIPANTS

African American Study of Kidney Disease and Hypertension (AASK) participants with available baseline serum samples for biomarker measurement.

PREDICTORS

Baseline serum levels of soluble tumor necrosis factor receptor 1 (sTNFR1), sTNFR2, tumor necrosis factor α (TNF-α), and interferon γ (IFN-γ).

OUTCOMES

Incident KFRT, all-cause mortality.

ANALYTICAL APPROACH

Cox proportional hazards models.

RESULTS

Among 500 participants with available samples, mean glomerular filtration rate was 44.7mL/min/1.73m², and median urinary protein-creatinine ratio was 0.09g/g at baseline. Over a median follow up of 9.6 years, there were 161 (32%) KFRT and 113 (23%) death events. In models adjusted for demographic and clinical factors and baseline kidney function, each 2-fold higher baseline level of sTNFR1, sTNFR2, and TNF-α was associated with 3.66-fold (95% CI, 2.31-5.80), 2.29-fold (95% CI, 1.60-3.29), and 1.35-fold (95% CI, 1.07-1.71) greater risks of KFRT, respectively; in comparison, each doubling of baseline suPAR concentration was associated with 1.39-fold (95% CI, 1.04-1.86) greater risk of KFRT. sTNFR1, sTNFR2, and TNF-α were also significantly associated with death (up to 2.2-fold higher risks per 2-fold higher baseline levels; P≤0.01). IFN-γ was not associated with either outcome. None of the biomarkers modified the association of APOL1 high-risk status (genetic risk factors for kidney disease among individuals of African ancestry) with KFRT (P>0.05 for interaction).

LIMITATIONS

Limited generalizability to other ethnic groups or causes of CKD.

CONCLUSIONS

Among African Americans with CKD attributed to hypertension, baseline levels of sTNFR1, sTNFR2, and TNF-α but not IFN-γ were associated with KFRT and mortality.

Liver and Kidney Recipient Selection of Hepatitis C Virus Viremic Donors: Meeting Consensus Report From the 2019 Controversies in Transplantation

The development of multiple highly effective and safe direct-acting antivirals to treat hepatitis C virus (HCV) has resulted in greater ease and confidence in managing HCV infection in transplant recipients that in turn has impacted the solid organ transplant community as well. In the United States, the opioid epidemic has increased the number of overdose deaths with a concomitant increase in younger HCV viremic donors after brain death being identified. At the same time, a decrease in HCV viremic transplant candidates has led to a growing interest in exploring the use of HCV viremic liver and kidney donor allografts in HCV-negative recipients. To date, experience with the use of HCV viremic liver and kidney allografts in HCV-negative recipients is limited to a few small prospective research trials, case series, and case reports. There are also limited data on recipient and donor selection for HCV viremic liver and kidney allografts. In response to this rapidly changing landscape in the United States, experts in the field of viral hepatitis and liver and kidney transplantation convened a meeting to review current data on liver and kidney recipient selection and developed consensus opinions related specifically to recipient and donor selection of HCV viremic liver and kidney allografts.

Transplanting hepatitis C virus-infected hearts into uninfected recipients: A single-arm trial

The advent of direct-acting antiviral therapy for hepatitis C virus (HCV) has generated tremendous interest in transplanting organs from HCV-infected donors. We conducted a single-arm trial of orthotopic heart transplantation (OHT) from HCV-infected donors into uninfected recipients, followed by elbasvir/grazoprevir treatment after recipient HCV was first detected (NCT03146741; sponsor: Merck). We enrolled OHT candidates aged 40-65 years; left ventricular assist device (LVAD) support and liver disease were exclusions. We accepted hearts from HCV-genotype 1 donors. From May 16, 2017 to May 10, 2018, 20 patients consented for screening and enrolled, and 10 (median age 52.5 years; 80% male) underwent OHT. The median wait from UNOS opt-in for HCV nucleic-acid-test (NAT)+ donor offers to OHT was 39 days (interquartile range [IQR] 17-57). The median donor age was 34 years (IQR 31-37). Initial recipient HCV RNA levels ranged from 25 IU/mL to 40 million IU/mL, but all 10 patients had rapid decline in HCV NAT after elbasvir/grazoprevir treatment. Nine recipients achieved sustained virologic response at 12 weeks (SVR-12). The 10th recipient had a positive cross-match, experienced antibody-mediated rejection and multi-organ failure, and died on day 79. No serious adverse events occurred from HCV transmission or treatment. These short-term results suggest that HCV-negative candidates transplanted with HCV-infected hearts have acceptable outcomes.

Tracing Donor-MHC Class II Reactive B cells in Mouse Cardiac Transplantation: Delayed CTLA4-Ig Treatment Prevents Memory Alloreactive B-Cell Generation

BACKGROUND

The dual role of B cells as drivers and suppressors of the immune responses have underscored the need to trace the fate of B cells recognizing donor major histocompatibility complex class I and class II after allograft transplantation.

METHODS

In this study, we used donor class II tetramers to trace the fate of I-E-specific B cells after immunization with BALB/c spleen cells or cardiac transplantation, in naive or sensitized C57BL/6 recipients. We combined this approach with genetic lineage tracing of memory B cells in activation-induced cytidine deaminase regulated Cre transgenic mice crossed to the ROSA26-enhanced yellow fluorescent protein reporter mice to track endogenous I-E-specific memory B cell generation.

RESULTS

Immunization with BALB/c splenocytes or heart transplantation induced an expansion and differentiation of I-E-specific B cells into germinal center B cells, whereas BALB/c heart transplantation into sensitized recipients induced the preferential differentiation into antibody-secreting cells. A 10.8-fold increase in the frequency of I-E-specific memory B cells was observed by day 42 postimmunization. Treatment with CTLA4-Ig starting on day 0 or day 7 postimmunization abrogated I-E-specific memory B cell generation and sensitized humoral responses, but not if treatment commenced on day 14.

CONCLUSIONS

The majority of donor-specific memory B cells are generated between days 7 and 14 postimmunization, thus revealing a flexible timeframe whereby delayed CTLA4-Ig administration can inhibit sensitization and the generation of memory graft-reactive B cells.