Banff Human Organ Transplant Transcripts Correlate with Renal Allograft Pathology and Outcome: Importance of Capillaritis and Subpathologic Rejection.

BACKGROUND: To seek insights into the pathogenesis of chronic active antibody-mediated rejection (CAMR), we performed mRNA analysis and correlated transcripts with pathologic component scores and graft outcomes. METHODS: We utilized the NanoString nCounter platform and the Banff Human Organ Transplant gene panel to quantify transcripts on 326 archived renal allograft biopsy samples. This system allowed correlation of transcripts with Banff pathology scores from the same tissue block and correlation with long-term outcomes. RESULTS: The only pathology score that correlated with AMR pathways in CAMR was peritubular capillaritis (ptc). C4d, cg, g, v, i, t, or ci scores did not correlate. DSA-negative CAMR had lower AMR pathway scores than DSA-positive CAMR. Transcript analysis in non-CAMR biopsies yielded evidence of increased risk of later CAMR. Among 108 patients without histologic CAMR, 23 developed overt biopsy-documented CAMR within 5 years and as a group had higher AMR pathway scores (P=3.4 × 10-5). Random forest analysis correlated 3-year graft loss with elevated damage, innate immunity, and macrophage pathway scores in CAMR and TCMR. Graft failure in CAMR was associated with TCMR transcripts but not with AMR transcripts, and graft failure in TCMR was associated with AMR transcripts but not with TCMR transcripts. CONCLUSIONS: Peritubular capillary inflammation and DSA are the primary drivers of AMR transcript elevation. Transcripts revealed subpathological evidence of AMR, which often preceded histologic CAMR and subpathological evidence of TCMR that predicted graft loss in CAMR.

Racial disparities in preemptive waitlisting and deceased donor kidney transplantation: Ethics and solutions.

Kidney transplantation prior to dialysis, known as "preemptive transplant," enables patients to live longer and avoid the substantial quality of life burdens due to chronic dialysis. Deceased donor kidneys are a public resource that ought to provide health benefits equitably. Unfortunately, White, better educated, and privately insured patients enjoy disproportionate access to preemptive transplantation using deceased donor kidneys. This problem has persisted for decades and is exacerbated by the first-come, first-served approach to kidney allocation for predialysis patients. In this Personal Viewpoint, we describe the diverse barriers to preemptive waitlisting and kidney transplant. The analysis focuses on healthcare system features that particularly disadvantage Black patients, such as the waitlisting eligibility criterion of a single glomerular filtration rate or creatinine clearance ≤20 ml/min, and neglect of wide variation in the rate of progression to end-stage kidney disease (ESKD) in allocating preemptive transplants. We propose initiatives to improve equity including: (1) standardization of waitlisting eligibility criteria related to kidney function; (2) aggressive education for clinicians about early transplant referral; (3) innovations in electronic medical record capabilities; and (4) rapid status 7 listing by centers. If those initiatives fail, the transplant field should consider eliminating preemptive waitlisting and transplantation with deceased donor kidneys.

Temporal trends and impact of willingness to accept organs from donors with hepatitis C virus.

Direct-acting antivirals (DAA) transformed hepatitis C virus (HCV) treatment in 2014; however, their impact on transplant candidates' willingness to accept (CWTA) organs from HCV+ donors remains uncertain. We retrospectively studied Organ Procurement and Transplantation Network data from 2008 to 2019, investigating CWTA different organs from HCV+ donors over time, using segmented multivariable logistic regression, and how that influenced wait-time and deceased-donor transplantation (DDTx) probability, using multivariable logistic or linear regression. We found that DAA availability was associated with a marked increase in CWTA in all organs from HCV+ donors except intestine. By December 2020, 40% of kidney, 33% of kidney-pancreas, 42% of pancreas, over 50% of liver, heart, lung, heart-lung, and 9% of intestine candidates waitlisted were CWTA an organ from HCV+ donors. Compared with pre-DAA, yearly CWTA kidney from HCV+ donors increased post-DAA 1.78 1.811.83 -fold, kidney-pancreas 2 .52 2.78 3.07 -fold, pancreas 3.15 3.69 4.43 -fold, liver 1.53 1.541.56 -fold, heart 1 .92 2.02 .08 -fold, and lung 2.00 2.12 .20 -fold. CWTA kidney and liver from HCV+ donors significantly increased DDTx probability post-DAA (1.98 2.042.1 -fold and 1.24 1.291.33 -fold, respectively) and shortened kidney candidates' wait-time78 90101 days (Mean with 95% CI). CWTA organs from HCV+ donors rose significantly with DAA availability, benefitting kidney and liver candidates with increased DDTx rates and shortened kidney candidates' wait time. Further long-term outcomes investigation and standardized organ from HCV+ donors' education could improve both provider and patient acceptance and utilization.

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.

Process of selecting and educating HCV-uninfected kidney waiting-list candidates for HCV-infected kidney transplantation.

Long waiting times for kidney transplant (KT) and the high risk of mortality on dialysis have prompted investigation into strategies to utilize hepatitis C virus (HCV)-infected organs to decrease discard rates of potentially viable kidneys. Due the opioid epidemic, the number of HCV-infected donors has increased significantly. With the development of direct-acting antiviral therapies for HCV infection, now more than 95% of patients who received treatment are cured. Experimental trials have used direct-acting antiviral therapy to treat HCV infection in HCV-uninfected transplant recipients of kidneys from HCV-viremic donors. To date, HCV has been eradicated in all cases. Though these strategies will potentially increase the donor pool of available kidneys, shorten waitlist times, and ultimately decrease mortality in patients waiting for KT, identifying the ideal candidates and educating them about a protocol to utilize direct-acting antiviral therapy to cure HCV after it is transmitted is essential. We present our approach to patient selection and education for a clinical trial in transplantation of HCV viremic kidneys into uninfected recipients.

Treatment of hepatitis C virus-associated mixed cryoglobulinemia with direct-acting antiviral agents.

UNLABELLED: Hepatitis C virus (HCV) is the most common cause of mixed cryoglobulinemia syndrome (MCS). The efficacy and safety of all-oral direct-acting antiviral (DAA) therapy in HCV-associated MCS (HCV-MCS) is largely unknown. The authors studied case series of patients with HCV-MCS who were treated with sofosbuvir-based regimens and historical controls treated with pegylated interferon and ribavirin in a single health care network. HCV-MCS was defined by circulating cryoglobulin associated with systemic vasculitis symptoms. Renal involvement (n = 7) was established by kidney biopsy (n = 5) or by two or more of the following clinical findings: reduced kidney function, proteinuria, or hematuria with other causes excluded (n = 2). Twelve patients received DAA therapy between December 2013 and September 2014. Median age was 61 years, 58% were male, and 50% had cirrhosis. Median baseline serum creatinine was 0.97 mg/dL (range 0.7-2.47). Four patients received rituximab concurrent with DAA therapy. Sustained virological response rate at 12 weeks (SVR12) was 83% overall. Patients with glomerulonephritis who achieved SVR12 experienced an improvement in serum creatinine and a reduction in proteinuria. Cryoglobulin levels decreased in 89% of patients, with median percent decreasing from 1.5% to 0.5% and completely disappearing in four of nine cases who had cryoglobulins measured after treatment. Serious adverse events were infrequent (17%). In contrast, the historical cohort treated with pegylated interferon and ribavirin experienced only 10% SVR12, with 100% experiencing at least one adverse event and 50% experiencing premature discontinuation due to adverse events. CONCLUSION: SVR12 rates for sofosbuvir-based DAA regimens in HCV-MCS were 83%, significantly higher than historical controls treated with pegylated interferon and ribavirin; patients with glomerulonephritis experienced improvement in renal function, including those not concomitantly treated with immunosuppression.

Shear wave elastography in chronic kidney disease: a pilot experience in native kidneys.

BACKGROUND: There currently is a need for a non-invasive measure of renal fibrosis. We aim to explore whether shear wave elastography (SWE)-derived estimates of tissue stiffness may serve as a non-invasive biomarker that can distinguish normal and abnormal renal parenchymal tissue. METHODS: Participants with CKD (by estimated GFR) and healthy volunteers underwent SWE. Renal elasticity was estimated as Young's modulus (YM) in kilopascals (kPa). Univariate Wilcoxon rank-sum tests were used. RESULTS: Twenty-five participants with CKD (median GFR 38 mL/min; quartile 1, quartile 3 28, 42) and 20 healthy controls without CKD underwent SWE performed by a single radiologist. CKD was associated with increased median YM (9.40 [5.55, 22.35] vs. 4.40 [3.68, 5.70] kPa; p = 0.002) and higher median intra-subject inter-measurement estimated YM's variability (4.27 [2.89, 9.90] vs. 1.51 [1.21, 2.05] kPa; p < 0.001). CONCLUSIONS: SWE-derived estimates of renal stiffness and intra-subject estimated stiffness variability are higher in patients with CKD than in healthy controls. Renal fibrosis is a plausible explanation for the observed difference in YM. Further studies are required to determine the relationship between YM, estimated renal stiffness, and renal fibrosis severity.

New susceptibility loci associated with kidney disease in type 1 diabetes.

Diabetic kidney disease, or diabetic nephropathy (DN), is a major complication of diabetes and the leading cause of end-stage renal disease (ESRD) that requires dialysis treatment or kidney transplantation. In addition to the decrease in the quality of life, DN accounts for a large proportion of the excess mortality associated with type 1 diabetes (T1D). Whereas the degree of glycemia plays a pivotal role in DN, a subset of individuals with poorly controlled T1D do not develop DN. Furthermore, strong familial aggregation supports genetic susceptibility to DN. However, the genes and the molecular mechanisms behind the disease remain poorly understood, and current therapeutic strategies rarely result in reversal of DN. In the GEnetics of Nephropathy: an International Effort (GENIE) consortium, we have undertaken a meta-analysis of genome-wide association studies (GWAS) of T1D DN comprising ~2.4 million single nucleotide polymorphisms (SNPs) imputed in 6,691 individuals. After additional genotyping of 41 top ranked SNPs representing 24 independent signals in 5,873 individuals, combined meta-analysis revealed association of two SNPs with ESRD: rs7583877 in the AFF3 gene (P = 1.2 × 10(-8)) and an intergenic SNP on chromosome 15q26 between the genes RGMA and MCTP2, rs12437854 (P = 2.0 × 10(-9)). Functional data suggest that AFF3 influences renal tubule fibrosis via the transforming growth factor-beta (TGF-ß1) pathway. The strongest association with DN as a primary phenotype was seen for an intronic SNP in the ERBB4 gene (rs7588550, P = 2.1 × 10(-7)), a gene with type 2 diabetes DN differential expression and in the same intron as a variant with cis-eQTL expression of ERBB4. All these detected associations represent new signals in the pathogenesis of DN.

Chromosome 2q31.1 associates with ESRD in women with type 1 diabetes.

Sex and genetic variation influence the risk of developing diabetic nephropathy and ESRD in patients with type 1 diabetes. We performed a genome-wide association study in a cohort of 3652 patients from the Finnish Diabetic Nephropathy (FinnDiane) Study with type 1 diabetes to determine whether sex-specific genetic risk factors for ESRD exist. A common variant, rs4972593 on chromosome 2q31.1, was associated with ESRD in women (P<5×10(-8)) but not in men (P=0.77). This association was replicated in the meta-analysis of three independent type 1 diabetes cohorts (P=0.02) and remained significant for women (P<5×10(-8); odds ratio, 1.81 [95% confidence interval, 1.47 to 2.24]) upon combined meta-analysis of the discovery and replication cohorts. rs4972593 is located between the genes that code for the Sp3 transcription factor, which interacts directly with estrogen receptor α and regulates the expression of genes linked to glomerular function and the pathogenesis of nephropathy, and the CDCA7 transcription factor, which regulates cell proliferation. Further examination revealed potential transcription factor-binding sites within rs4972593 and predicted eight estrogen-responsive elements within 5 kb of this locus. Moreover, we found sex-specific differences in the glomerular expression levels of SP3 (P=0.004). Overall, these results suggest that rs4972593 is a sex-specific genetic variant associated with ESRD in patients with type 1 diabetes and may underlie the sex-specific protection against ESRD.