Monoallelic pathogenic ALG5 variants cause atypical polycystic kidney disease and interstitial fibrosis.

Disorders of the autosomal dominant polycystic kidney disease (ADPKD) spectrum are characterized by the development of kidney cysts and progressive kidney function decline. PKD1 and PKD2, encoding polycystin (PC)1 and 2, are the two major genes associated with ADPKD; other genes include IFT140, GANAB, DNAJB11, and ALG9. Genetic testing remains inconclusive in ∼7% of the families. We performed whole-exome sequencing in a large multiplex genetically unresolved (GUR) family affected by ADPKD-like symptoms and identified a monoallelic frameshift variant (c.703_704delCA) in ALG5. ALG5 encodes an endoplasmic-reticulum-resident enzyme required for addition of glucose molecules to the assembling N-glycan precursors. To identify additional families, we screened a cohort of 1,213 families with ADPKD-like and/or autosomal-dominant tubulointerstitial kidney diseases (ADTKD), GUR (n = 137) or naive to genetic testing (n = 1,076), by targeted massively parallel sequencing, and we accessed Genomics England 100,000 Genomes Project data. Four additional families with pathogenic variants in ALG5 were identified. Clinical presentation was consistent in the 23 affected members, with non-enlarged cystic kidneys and few or no liver cysts; 8 subjects reached end-stage kidney disease from 62 to 91 years of age. We demonstrate that ALG5 haploinsufficiency is sufficient to alter the synthesis of the N-glycan chain in renal epithelial cells. We also show that ALG5 is required for PC1 maturation and membrane and ciliary localization and that heterozygous loss of ALG5 affects PC1 maturation. Overall, our results indicate that monoallelic variants of ALG5 lead to a disorder of the ADPKD-spectrum characterized by multiple small kidney cysts, progressive interstitial fibrosis, and kidney function decline.

Rituximab as maintenance therapy for ANCA-associated vasculitides: pooled analysis and long-term outcome of 277 patients included in the MAINRITSAN trials.

OBJECTIVE: To compare the long-term efficacy and safety of azathioprine (AZA), 18-month fixed-schedule rituximab (RTX), 18-month tailored RTX and 36-month RTX in preventing relapses in patients with antineutrophil cytoplasmic antibody (ANCA)-associated vasculitis who achieved a complete remission after induction therapy. Patients treated with 36-month RTX received either a fixed or a tailored regimen for the first 18 months and a fixed regimen for the last 18 months (36-month fixed/fixed RTX and 36-month tailored/fixed RTX, respectively). METHODS: The Maintenance of Remission using Rituximab in Systemic ANCA-associated Vasculitis (MAINRITSAN) trials sequentially compared: 18-month fixed-schedule RTX versus AZA (MAINRITSAN); 18-month fixed-schedule RTX versus 18-month tailored-RTX (MAINRITSAN2); and extended therapy to 36 months with four additional RTX infusions after MAINRITSAN2 versus placebo (MAINRITSAN3). Patients were then followed prospectively through month 84 and their data were pooled to analyse relapses and adverse events. The primary endpoint was relapse-free survival at month 84. RESULTS: 277 patients were enrolled and divided in 5 groups: AZA (n=58), 18-month fixed-schedule RTX (n=97), 18-month tailored-RTX (n=40), 36-month tailored/fixed RTX (n=42), 36-month fixed/fixed RTX (n=41). After adjustment for prognostic factors, 18-month fixed-schedule RTX was superior to AZA in preventing major relapses at month 84 (HR 0.38, 95% CI 0.20 to 0.71). The 18-month tailored-RTX regimen was associated with an increased risk of major relapse compared with fixed-schedule regimen (HR 2.92, 95% CI 1.43 to 5.96). The risk of major relapse was similar between 36-month fixed/fixed and 18-month fixed-RTX (HR 0.69, 95% CI 0.38 to 1.25). CONCLUSIONS: According to these results, it appears that the 84-month remission rate is higher with an 18-month fixed RTX regimen compared with AZA and 18-month tailored RTX. Also, extending RTX to 36 months does not appear to reduce the long-term relapse rate compared with the 18-month fixed RTX regimen. However, as this study was underpowered to make this comparison, further prospective studies are needed to determine the potential long-term benefits of extending treatment in these patients.

Kidney Transplantation in Patients With AA Amyloidosis: Outcomes in a French Multicenter Cohort.

RATIONALE & OBJECTIVE: Outcomes of kidney transplantation for patients with renal AA amyloidosis are uncertain, with reports of poor survival and high rates of disease recurrence. However, the data are inconclusive and mostly based on studies from the early 2000s and earlier. STUDY DESIGN: Retrospective multicenter cohort study. SETTING & PARTICIPANTS: We searched the French national transplant database to identify all patients with renal AA amyloidosis who underwent kidney transplantation between 2008 and 2018. EXPOSURES: Age, cause of amyloidosis, use of biotherapies, and C-reactive protein levels. OUTCOMES: Outcomes were all-cause mortality and allograft loss. We also reported amyloidosis allograft recurrence, occurrence of acute rejection episodes, as well as infectious, cardiovascular, and neoplastic disease events. ANALYTICAL APPROACH: Kaplan-Meier estimator for mortality and cumulative incidence function method for allograft loss. Factors associated with patient and allograft survival were investigated using a Cox proportional hazards model and a cause-specific hazards model, respectively. RESULTS: 86 patients who received kidney transplants for AA amyloidosis at 26 French centers were included. The median age was 49.4 years (IQR, 39.7-61.1). The main cause of amyloidosis was familial Mediterranean fever (37 cases; 43%). 16 (18.6%) patients received biotherapy after transplantation. Patient survival rates were 94.0% (95% CI, 89.1-99.2) at 1 year and 85.5% (77.8-94.0) at 5 years after transplantation. Cumulative incidences of allograft loss were 10.5% (4.0-17.0) at 1 year and 13.0% (5.8-20.1) at 5 years after transplantation. Histologically proven AA amyloidosis recurrence occurred in 5 transplants (5.8%). An infection requiring hospitalization developed in 55.8% of cases, and there was a 27.9% incidence of acute allograft rejection. Multivariable analysis showed that C-reactive protein concentration at the time of transplantation was associated with patient survival (HR, 1.01; 95% CI, 1.00-1.02; P=0.01) and allograft survival (HR, 1.68; 95% CI, 1.10-2.57; P=0.02). LIMITATIONS: The study lacked a control group, and the effect of biotherapies on transplantation outcomes could not be explored. CONCLUSIONS: This relatively contemporary cohort of patients who received a kidney transplant for AA amyloidosis experienced favorable rates of survival and lower recurrence rates than previously reported. These data support the practice of treating these patients with kidney transplantation for end-stage kidney disease. PLAIN-LANGUAGE SUMMARY: AA amyloidosis is a severe and rare disease. Kidney involvement is frequent and leads to end-stage kidney disease. Because of the involvement of other organs, these patients are often frail, which has raised concerns about their suitability for kidney transplantation. We reviewed all patients with AA amyloidosis nephropathy who underwent kidney transplantation in France in the recent era (2008-2018) and found that the outcomes after kidney transplantation were favorable, with 85.5% of patients still alive 5 years after transplantation, a survival rate that is comparable to the outcomes of patients receiving a transplant for other forms of kidney diseases. Recurrence of amyloidosis in the transplanted kidney was infrequent (5.8%). These data support the practice of kidney transplantation for patients with AA amyloidosis who experience kidney failure.

Mass cytometry reveals atypical immune profile notably impaired maturation of memory CD4 T with Gb3-related CD27 expression in CD4 T cells in Fabry disease.

Fabry disease (FD) is an X-linked disease characterized by an accumulation of glycosphingolipids, notably of globotriaosylceramide (Gb3) and globotriaosylsphingosine (lysoGb3) leading to renal failure, cardiomyopathy, and cerebral strokes. Inflammatory processes are involved in the pathophysiology. We investigated the immunological phenotype of peripheral blood mononuclear cells in Fabry patients depending on the clinical phenotype, treatment, Gb3, and lysoGb3 levels and the presence of anti-drug antibodies (ADA). Leucocytes from 41 male patients and 20 controls were analyzed with mass cytometry using both unsupervised and supervised algorithms. FD patients had an increased expression of CD27 and CD28 in memory CD45- and CD45 + CCR7-CD4 T cells (respectively p < 0.014 and p < 0.02). Percentage of CD45RA-CCR7-CD27 + CD28+ cells in CD4 T cells was correlated with plasma lysoGb3 (r = 0.60; p = 0.0036) and phenotype (p < 0.003). The correlation between Gb3 and CD27 in CD4 T cells almost reached significance (r = 0.33; p = 0.058). There was no immune profile associated with the presence of ADA. Treatment with agalsidase beta was associated with an increased proportion of Natural Killer cells. These findings provide valuable insights for understanding FD, linking Gb3 accumulation to inflammation, and proposing new prognostic biomarkers.

Solid Organ Transplant Litigation at One of Europe's Largest University Hospitals.

Due to its intrinsic complexity and the principle of collective solidarity that governs it, solid organ transplantation (SOT) seems to have been spared from the increase in litigation related to medical activity. Litigation relating to solid organ transplantation that took place in the 29 units of the Assistance Publique-Hôpitaux de Paris and was the subject of a judicial decision between 2015 and 2022 was studied. A total of 52 cases of SOT were recorded, all in adults, representing 1.1% of all cases and increasing from 0.71% to 1.5% over 7 years. The organs transplanted were 25 kidneys (48%), 19 livers (37%), 5 hearts (9%) and 3 lungs (6%). For kidney transplants, 11 complaints (44%) were related to living donor procedures and 6 to donors. The main causes of complaints were early post-operative complications in 31 cases (60%) and late complications in 13 cases (25%). The verdicts were in favour of the institution in 41 cases (79%). Solid organ transplants are increasingly the subject of litigation. Although the medical institution was not held liable in almost 80% of cases, this study makes a strong case for patients, living donors and their relatives to be better informed about SOT.

Glomerular Filtration Rate Measured Based on Iomeprol Clearance Assessed at CT Urography in Living Kidney Donor Candidates.

Background Estimating glomerular filtration rate (GFR) from serum creatinine can be inaccurate, and current procedures for measuring GFR are time-consuming and cumbersome. Purpose To develop a method for measuring GFR based on iomeprol clearance assessed at CT urography in kidney donor candidates and compare this with iohexol clearance (reference standard for measuring GFR). Materials and Methods This cross-sectional retrospective study included data from kidney donor candidates who underwent both iohexol clearance and CT urography between July 2016 and October 2022. CT-measured GFR was calculated as the iomeprol excretion rate in the urinary system between arterial and excretory phases (Hounsfield units times milliliters per minute) divided by a surrogate for serum iomeprol concentration in the aorta at the midpoint (in Hounsfield units). Performance of CT-measured GFR was assessed with use of mean bias (mean difference between CT-measured GFR and iohexol clearance), precision (the distance between quartile 1 and quartile 3 of the bias [quartile 3 minus quartile 1], with a small value indicating high precision), and accuracy (percentage of CT-measured GFR values falling within 10%, 20%, and 30% of iohexol clearance values). Intraobserver agreement was assessed for 30 randomly selected individuals with the Lin concordance correlation coefficient. Results A total of 75 kidney donor candidates were included (mean age, 51 years ± 13 [SD]; 45 female). The CT-measured GFR was unbiased (1.1 mL/min/1.73 m2 [95% CI: -1.9, 4.1]) and highly precise (16.2 mL/min/1.73 m2 [quartiles 1 to 3, -6.6 to 9.6]). The accuracy of CT-measured GFR within 10%, 20%, and 30% was 61.3% (95% CI: 50.3, 72.4), 88.0% (95% CI: 80.7, 95.4), and 100%, respectively. Concordance between CT-based GFR measurements taken 2 months apart was almost perfect (correlation coefficient, 0.99 [95% CI: 0.98, 0.99]). Conclusion In living kidney donors, GFR measured based on iomeprol clearance assessed at CT urography showed good agreement with GFR measured based on iohexol clearance. © RSNA, 2023 Supplemental material is available for this article. See also the editorial by Davenport in this issue.

Belatacept rescue conversion in kidney transplant recipients with vascular lesions (Banff cv score >2): a retrospective cohort study.

BACKGROUND: Immunosuppression in kidney transplant recipients with decreased graft function and histological vascular changes can be particularly challenging. The impact of a late rescue conversion to belatacept on kidney graft survival in this context has never been studied. METHODS: We report a bicentric retrospective cohort study comparing a calcineurin inhibitor (CNI) to belatacept switch versus CNI continuation in 139 kidney transplant recipients with histological kidney vascular damage (cv ≥2, g + cpt ≤1, i + t ≤1) and low estimated glomerular filtration rate (≤40 mL/min/1.73 m²). Primary outcome was death-censored graft survival. RESULTS: During the study follow-up, 10 graft losses (14.5%) occurred in the belatacept group (n = 69) versus 26 (37.1%) in the matched CNI group (n = 70) (P = .005). Death-censored graft survival was significantly higher in the belatacept group (P = .001). At 3 years, graft survival was 84.0% in the belatacept group compared with 65.1% in the control group. Continuing CNI was an independent risk factor for graft loss [hazard ratio (HR) 3.46; P < .005]. The incidence of cellular rejection after the conversion was low (4.3% in both groups) and not significantly different between groups (P = .84). Patients switched to belatacept developed significantly less donor-specific antibodies de novo. Belatacept was an independent risk factor for the occurrence of opportunistic infections (HR 4.84; P < .005). CONCLUSION: The replacement of CNI with belatacept in patients with decreased allograft function and vascular lesions is associated with an improvement in graft survival and represents a valuable option in a context of organ shortage. Caution should be exercised regarding the increased risk of opportunistic infection.

Additional Benefits of Rituximab and Plasma Exchange on Top of Standard Induction Therapy in Kidney Transplant Recipients With a Negative CDC Crossmatch but High Preformed Donor Specific Antibody Titer.

Optimal induction strategy in highly sensitized kidney transplant recipients (KTRs) is still a matter of debate. The place of therapies, such as plasma exchange and rituximab, with potential side effects and high cost, is not clearly established. We compared two induction strategies with (intensive) or without (standard) rituximab and plasma exchange in KTRs with high levels of preformed DSA transplanted between 2012 and 2019. Sixty KTRs with a mean age of 52.2 ± 12.2 years were included, 36 receiving standard and 24 intensive induction. Mean fluorescence intensity of immunodominant DSA in the cohort was 8,903 ± 5,469 pre-transplantation and similar in both groups. DSA level decrease was similar at 3 and 12 months after transplantation in the two groups. An intensive induction strategy was not associated with better graft or patient survival, nor more infectious complications. The proportion of patients with rejection during the first year was similar (33% in each group), but rejection occurred later in the intensive group (211 ± 188 days, vs. 79 ± 158 days in the standard group, p < 0.01). Our study suggests that an intensive induction therapy including rituximab and plasma exchanges in highly sensitized kidney recipients is not associated with better graft survival but may delay biopsy-proven rejection.

Three-Year Outcomes in Kidney Transplant Recipients Switched From Calcineurin Inhibitor-Based Regimens to Belatacept as a Rescue Therapy.

Background: The long-term benefits of conversion from calcineurin inhibitors (CNIs) to belatacept in kidney transplant recipients (KTr) are poorly documented.Methods: A single-center retrospective work to study first-time CNI to belatacept conversion as a rescue therapy [eGFR <30 ml/min/1.73 m2, chronic histological lesions, or CNI-induced thrombotic microangiopathy (TMA)]. Patient and kidney allograft survivals, eGFR, severe adverse events, donor-specific antibodies (DSA), and histological data were recorded over 36 months after conversion. Results: We included N = 115 KTr. The leading cause for switching was chronic histological lesions with non-optimal eGFR (56.5%). Three years after conversion, patient, and death-censored kidney allograft survivals were 88% and 92%, respectively, eGFR increased significantly from 31.5 ± 17.5 to 36.7 ± 15.7 ml/min/1.73 m2 (p < 0.01), the rejection rate was 10.4%, OI incidence was 5.2 (2.9-7.6) per 100 person-years. Older age was associated with death, eGFR was not associated with death nor allograft loss. No patient developed dnDSA at M36 after conversion. CNI-induced TMA disappeared in all cases without eculizumab use. Microvascular inflammation and chronic lesions remained stable. Conclusion: Post-KT conversion from CNIs to belatacept, as rescue therapy, is safe and beneficial irrespective of the switch timing and could represent a good compromise facing organ shortage. Age and eGFR at conversion should be considered in the decision whether to switch.

Is COVID-19 infection more severe in kidney transplant recipients?

There are no studies which have compared the risk of severe COVID-19 and related mortality between transplant recipients and nontransplant patients. We enrolled two groups of patients hospitalized for COVID-19, that is, kidney transplant recipients (KTR) from the French Registry of Solid Organ Transplant (n = 306) and a single-center cohort of nontransplant patients (n = 795). An analysis was performed among subgroups matched for age and risk factors for severe COVID-19 or mortality. Severe COVID-19 was defined as admission (or transfer) to an intensive care unit, need for mechanical ventilation, or death. Transplant recipients were younger and had more comorbidities compared to nontransplant patients. They presented with higher creatinine levels and developed more episodes of acute kidney injury. After matching, the 30-day cumulative incidence of severe COVID-19 did not differ between KTR and nontransplant patients; however, 30-day COVID-19-related mortality was significantly higher in KTR (17.9% vs 11.4%, respectively, p = .038). Age >60 years, cardiovascular disease, dyspnea, fever, lymphopenia, and C-reactive protein (CRP) were associated with severe COVID-19 in univariate analysis, whereas transplant status and serum creatinine levels were not. Age >60 years, hypertension, cardiovascular disease, diabetes, CRP >60 mg/L, lymphopenia, kidney transplant status (HR = 1.55), and creatinine level >115 µmol/L (HR = 2.32) were associated with COVID-19-related mortality in univariate analysis. In multivariable analysis, cardiovascular disease, dyspnea, and fever were associated with severe disease, whereas age >60 years, cardiovascular disease, dyspnea, fever, and creatinine level>115 µmol/L retained their independent associations with mortality. KTR had a higher COVID-19-related mortality compared to nontransplant hospitalized patients.

Comparison of the iliac, vaginal and umbilical graft extraction in robot-assisted laparoscopic living donor nephrectomy.

PURPOSE: To compare different extractions routes for robot-assisted living donor nephrectomy in terms of post-operative pain and renal function recovery. METHODS: Live donor kidney transplantation data from our institution were reviewed from November 2011 to March 2017. Postoperative pain was estimated using cumulative painkillers consumption. Variables were compared between the 3 groups with ANOVA for continuous data, χ2 test for categorial data. A survival analysis with Kaplan-Meier curve assessing time to transplant recipient nadir was performed to compare the renal function recovery. RESULTS: Sixty-three RLDN were performed (23 iliac, 23 vaginal and 17 umbilical extractions). There was no significant difference between the three groups in terms of operative time, blood lost, warm ischemia time, cumulative painkiller consumption and renal function recovery time. Postoperative complications for Umbilical, Vaginal and Iliac were, respectively, of 0, 3 and 1. No major difference was found between the 3 groups beside a slightly longer hospital stay in the iliac group. CONCLUSION: Iliac incision might impact post-operative pain with a moderate but significant longer hospital stay. Vaginal extraction is an option when cosmetic outcomes present a real demand. The three options appeared to be safe and should be discussed with the patient in regard of the surgeon experience.

Infectious disease consultation is effective in boosting vaccine coverage in patients awaiting kidney transplantation: A French prospective study.

Recommended preventive strategies before kidney transplantation include screening and treatment of latent tuberculosis infection (LTBI), and updating of the recommended vaccines. We prospectively evaluated in dedicated infectious diseases consultations, from 2014 to 2018, the clinical and vaccination data of new adult kidney allograft candidates. Patients were offered an updated vaccination schedule, if appropriate, and were screened for LTBI using chest imaging and interferon gamma release assay (IGRA). Overall, 467 patients with median age of 58 [46-66] years were evaluated, of whom 302 patients (65%) were men (sex ratio 1.83), and 333 (71%) were on dialysis. Main causes of renal insufficiency were diabetes (25%) and autoimmune nephropathies (18%). The vaccination coverage was low and varied according to the different types of vaccines and patients. Vaccination or immunization rates were 24%, 6%, 54%, and 51% for tetanus-diphtheria-polio-acellular pertussis, Pneumococcus, hepatitis B, and seasonal influenza, respectively. ID consultation successfully rose patients' vaccinations coverage, in fulfillment with recommendations, in 465 (99%) patients. LTBI treatment was administered in 78 (16.7%) patients and caused drug-related adverse events in 9 (11%). A dedicated infectious disease consultation should become a critical tool for coordinating infection prevention strategies.

Risk factors for intra-abdominal fungal infection after simultaneous pancreas-kidney transplantation: A single-center retrospective experience.

BACKGROUND: Data on the risk factors and outcome of intra-abdominal fungal infections (IAFI) following simultaneous pancreas-kidney transplantation (PKT) are scarce. MATERIALS/METHODS: A retrospective monocentric study was conducted on all patients who underwent simultaneous PKT from January 2007 to December 2016. Deep sites positive cultures for fungi during the first post-transplantation year were collected. Clinical, radiological, and microbiological data of proven and probable invasive fungal infections were analysed. RESULTS: Among sixteen PKT patients, 15 were included. Seven patients (47%) developed an invasive fungal infection, exclusively IAFI (six proven, one probable). The proven IAFI included four peritonitis, one pancreatic necrosis with infected hematoma, and one patient with positive preservation fluid only (PF). Candida albicans (n = 4) was the most prevalent species (associated with Galactomyces candidus in one case), C glabrata, C dubliniensis, and C krusei were found in one case each. Three patients had either a positive direct examination and/or culture for renal or pancreatic PF and the culture of PF was positive for the same species that caused IAFI. IAFIs were significantly associated with pancreatic graft arterial thrombosis (5/7 vs 0/8, P = .007) and fungal contamination of PF (3/7 vs 0/8, P = .008). Among patients with IAFI, all required an early surgical revision post-transplantation [1-18 days] and six had early or delayed pancreatic graft removal. One patient died in the first post-transplant year. CONCLUSION: IAFI is a common complication in PKT, associated with pancreatic graft thrombosis or fungal contamination of the graft PF, and can sometimes lead to pancreatic detransplantation.

Trimethoprim/sulfamethoxazole for nocardiosis in solid organ transplant recipients: Real-life data from a multicentre retrospective study.

BACKGROUND: Little is known regarding the optimal management of nocardiosis among solid organ transplant (SOT) recipients. It is often suggested to avoid trimethoprim/sulfamethoxazole (TMP-SMX) monotherapy in heavily immunocompromised patients (such as SOT recipients) and/or in case of severe or disseminated nocardiosis. Our aim was to report our experience with TMP-SMX monotherapy in SOT recipients with nocardiosis. METHODS: Using data from a previously published European study, we assessed the incidence of adverse events in SOT recipients receiving TMP-SMX monotherapy and assessed its effectiveness. RESULTS: Thirty-one SOT recipients with nocardiosis were included, mostly kidney transplant recipients (20/31, 65%). Eleven (36%) had disseminated infection, and four (13%) had brain nocardiosis. Most patients had lung and/or pleural involvement (26/31, 84%). Daily dose of trimethoprim at initiation was 10 [6.4-14.8] mg/kg. The median estimated glomerular filtration rate at time of diagnosis of nocardiosis was 44 [30-62] ml/min/1.73 m². TMP-SMX was discontinued prematurely in one third of the patients (10/31, 32%, mostly for hematological toxicity [n = 3] or increased serum creatinine [n = 3]). Focusing on the 24 (77%) patients who completed at least 30 days of TMP-SMX monotherapy, 4 had late (>30 days) drug discontinuation, 1 experienced treatment failure, and 19 completed planned TMP-SMX monotherapy. Clinical outcome was favorable in these 19 patients, despite the fact that 8 (42%) had disseminated infection and 2 (11%) brain nocardiosis. Overall, all-cause 1-year mortality was 10% (3/31). CONCLUSIONS: TMP-SMX monotherapy appears to be effective for the treatment of most nocardiosis among SOT recipients. Interventional studies are needed to compare its safety and effectiveness with those of other regimens used to treat posttransplant nocardiosis.

Ribavirin for Hepatitis E Virus Infection After Organ Transplantation: A Large European Retrospective Multicenter Study.

BACKGROUND: Ribavirin is currently recommended for treating chronic hepatitis E virus (HEV) infection. This retrospective European multicenter study aimed to assess the sustained virological response (SVR) in a large cohort of solid organ transplant (SOT) recipients with chronic HEV infection treated with ribavirin monotherapy (N = 255), to identify the predictive factors for SVR, and to evaluate the impact of HEV RNA mutations on virological response. METHODS: Data from 255 SOT recipients with chronic HEV infection from 30 European centers were analyzed. Ribavirin was given at the median dose of 600 (range, 29-1200) mg/day (mean, 8.6 ± 3.6 mg/kg/day) for a median duration of 3 (range, 0.25-18) months. RESULTS: After a first course of ribavirin, the SVR rate was 81.2%. It increased to 89.8% when some patients were offered a second course of ribavirin. An increased lymphocyte count at the initiation of therapy was a predictive factor for SVR, while poor hematological tolerance of ribavirin requiring its dose reduction (28%) and blood transfusion (15.7%) were associated with more relapse after ribavirin cessation. Pretreatment HEV polymerase mutations and de novo mutations under ribavirin did not have a negative impact on HEV clearance. Anemia was the main adverse event. CONCLUSIONS: This large-scale retrospective study confirms that ribavirin is highly efficient for treating chronic HEV infection in SOT recipients and shows that the predominant HEV RNA polymerase mutations found in this study do not affect the rate of HEV clearance.This large-scale retrospective study that included 255 solid organ transplant recipients confirms that ribavirin is highly efficient for treating chronic hepatitis E virus (HEV) infection and shows that HEV RNA polymerase mutations do not play a role in HEV clearance.

An initial report from the French SOT COVID Registry suggests high mortality due to COVID-19 in recipients of kidney transplants.

Notwithstanding the ongoing coronavirus disease-2019 (Covid-19) pandemic, information on its clinical presentation and prognosis in recipients of a kidney transplant remain scanty. The aim of this registry-based observational study was to explore characteristics and clinical outcomes of recipients of kidney transplants included in the French nationwide Registry of Solid Organ Transplant Recipients with Covid-19. Covid-19 was diagnosed in symptomatic patients who had a positive PCR assay for SARS-CoV-2 or having typical lung lesions on imaging. Clinical and laboratory characteristics, management of immunosuppression, treatment for Covid-19, and clinical outcomes (hospitalization, admission to intensive care unit, mechanical ventilation, or death) were recorded. Risk factors for severe disease or death were determined. Of the 279 patients, 243 were admitted to hospital and 36 were managed at home. The median age of hospitalized patients was 61.6 years; most had comorbidities (hypertension, 90.1%; overweight, 63.8%; diabetes, 41.3%; cardiovascular disease, 36.2%). Fever, cough, dyspnea, and diarrhea were the most common symptoms on admission. Laboratory findings revealed mild inflammation frequently accompanied by lymphopenia. Immunosuppressive drugs were generally withdrawn (calcineurin inhibitors: 28.7%; antimetabolites: 70.8%). Treatment was mainly based on hydroxychloroquine (24.7%), antiviral drugs (7.8%), and tocilizumab (5.3%). Severe Covid-19 occurred in 106 patients (46%). Forty-three hospitalized patients died (30-day mortality 22.8%). Multivariable analysis identified overweight, fever, and dyspnea as independent risk factors for severe disease, whereas age over 60 years, cardiovascular disease, and dyspnea were independently associated with mortality. Thus, Covid-19 in recipients of kidney transplants portends a high mortality rate. Proper management of immunosuppression and tailored treatment of this population remain challenging.

An international cohort study of autosomal dominant tubulointerstitial kidney disease due to REN mutations identifies distinct clinical subtypes.

There have been few clinical or scientific reports of autosomal dominant tubulointerstitial kidney disease due to REN mutations (ADTKD-REN), limiting characterization. To further study this, we formed an international cohort characterizing 111 individuals from 30 families with both clinical and laboratory findings. Sixty-nine individuals had a REN mutation in the signal peptide region (signal group), 27 in the prosegment (prosegment group), and 15 in the mature renin peptide (mature group). Signal group patients were most severely affected, presenting at a mean age of 19.7 years, with the prosegment group presenting at 22.4 years, and the mature group at 37 years. Anemia was present in childhood in 91% in the signal group, 69% prosegment, and none of the mature group. REN signal peptide mutations reduced hydrophobicity of the signal peptide, which is necessary for recognition and translocation across the endoplasmic reticulum, leading to aberrant delivery of preprorenin into the cytoplasm. REN mutations in the prosegment led to deposition of prorenin and renin in the endoplasmic reticulum-Golgi intermediate compartment and decreased prorenin secretion. Mutations in mature renin led to deposition of the mutant prorenin in the endoplasmic reticulum, similar to patients with ADTKD-UMOD, with a rate of progression to end stage kidney disease (63.6 years) that was significantly slower vs. the signal (53.1 years) and prosegment groups (50.8 years) (significant hazard ratio 0.367). Thus, clinical and laboratory studies revealed subtypes of ADTKD-REN that are pathophysiologically, diagnostically, and clinically distinct.

Reducing the initial number of rituximab maintenance-therapy infusions for ANCA-associated vasculitides: randomized-trial post-hoc analysis.

OBJECTIVE: The randomized, controlled MAINRITSAN2 trial was designed to compare the capacity of an individually tailored therapy [randomization day 0 (D0)], with reinfusion only when CD19+ lymphocytes or ANCA had reappeared, or if the latter's titre rose markedly, with that of five fixed-schedule 500-mg rituximab infusions [D0 + D14, then months (M) 6, 12 and 18] to maintain ANCA-associated vasculitis (AAV) remissions. Relapse rates did not differ at M28. This ancillary study was undertaken to evaluate the effect of omitting the D14 rituximab infusion on AAV relapse rates at M12. METHODS: MAINRITSAN2 trial data were subjected to post-hoc analyses of M3, M6, M9 and M12 relapse-free survival rates in each arm as primary end points. Exploratory subgroup analyses were run according to CYC or rituximab induction and newly diagnosed or relapsing AAV. RESULTS: At M3, M6, M9 and M12, respectively, among the 161 patients included, 79/80 (98.8%), 76/80 (95%), 74/80 (92.5%) and 73/80 (91.3%) from D0, and 80/81 (98.8%), 78/81 (96.3%), 76/81 (93.8%) and 76/81 (93.8%) from D0+D14 groups were alive and relapse-free. No between-group differences were observed. Results were not affected by CYC or rituximab induction, or newly diagnosed or relapsing AAV. CONCLUSIONS: We were not able to detect a difference between the relapse-free survival rates for up to M12 for the D0 and D0+D14 rituximab-infusion groups, which could suggest that omitting the D14 rituximab remission-maintenance dose did not modify the short-term relapse-free rate. Nevertheless, results at M12 may also have been influenced by the rituximab-infusion strategies for both groups.

Predictive value of mixed antigen screen beads in pre-transplant assessment of HLA immunization in solid organ transplant recipients.

Pre-transplant serum screening of anti-HLA antibodies is recommended for solid organ transplantations. Many laboratories use the less expensive bead-based screening assay as the main technique and, if positive, turn to single-antigen beads (SAB). We studied the correlations between these two immunoassays. We re-analyzed the raw data of the two assays in 3030 first organ transplant recipients, explored with the two tests. We performed a ROC curve analysis of the screening ratio to predict a positive SAB assay. The AUC were 0.72 and 0.64 for class I and class II. The optimal thresholds of screening ratios were 3.28 (class I) and 2.11 (class II). Whatever the class, the negative predictive value was low, around 40%, with 36% of discordant sera, as defined by negative screening and positive SAB. Testing class I discordant sera on acid-treated SAB showed that 54% of antibodies reacted against denatured HLA molecules. However, these screening-negative sera may contain donor-specific antibodies in 13.9% and 28.7% of cases for class I and class II, respectively, involved in antibody-mediated rejection with the same frequency as non-discordant sera. Given the low predictive value of screening, both assays should be performed at least once on the same serum before transplantation.

Daratumumab in Sensitized Kidney Transplantation: Potentials and Limitations of Experimental and Clinical Use.

BACKGROUND: Donor-specific antibodies are associated with increased risk of antibody-mediated rejection and decreased allograft survival. Therefore, reducing the risk of these antibodies remains a clinical need in transplantation. Plasma cells are a logical target of therapy given their critical role in antibody production. METHODS: To target plasma cells, we treated sensitized rhesus macaques with daratumumab (anti-CD38 mAb). Before transplant, we sensitized eight macaques with two sequential skin grafts from MHC-mismatched donors; four of them were also desensitized with daratumumab and plerixafor (anti-CXCR4). We also treated two patients with daratumumab in the context of transplant. RESULTS: The animals treated with daratumumab had significantly reduced donor-specific antibody levels compared with untreated controls (57.9% versus 13% reduction; P<0.05) and prolonged renal graft survival (28.0 days versus 5.2 days; P<0.01). However, the reduction in donor-specific antibodies was not maintained because all recipients demonstrated rapid rebound of antibodies, with profound T cell-mediated rejection. In the two clinical patients, a combined heart and kidney transplant recipient with refractory antibody-mediated rejection and a highly sensitized heart transplant candidate, we also observed a significant decrease in class 1 and 2 donor-specific antibodies that led to clinical improvement of antibody-mediated rejection and to heart graft access. CONCLUSIONS: Targeting CD38 with daratumumab significantly reduced anti-HLA antibodies and anti-HLA donor-specific antibodies in a nonhuman primate model and in two transplant clinical cases before and after transplant. This supports investigation of daratumumab as a potential therapeutic strategy; however, further research is needed regarding its use for both antibody-mediated rejection and desensitization.