Graft Biopsy Research Articles

Primary Hyperoxaluria Type 1: Clinical, Paraclinical, and Evolutionary Aspects in Adults from One Nephrology Center.

Primary hyperoxaluria type 1 (PH1) is a rare and inherited condition of urolithiasis. The aim of our study was to analyze clinical, paraclinical, and evolutionary aspects of PH1 in adult patients in our Nephrology department. We conducted a retrospective single-center study between 1990 and 2021. We collected patients followed for PH1 confirmed by genetic study and/or histopathological features of renal biopsy and morphoconstitutional analysis of the calculi. There were 25 patients with a gender ratio of 1.78. The median age at onset of symptoms was 18 years. A delay in diagnosis more than 10 years was noted in 13 cases. The genetic study found the I244T mutation in 17 cases and 33-34 InsC in 4 cases. A kidney biopsy was performed in 5 cases, on a native kidney in 4 cases and on a graft biopsy in one case. The analysis of calculi was done in 10 cases showing type Ic in 2 cases. After a median follow-up of 13 years (1 year-42 years), 14 patients progressed to end-stage chronic renal failure (ESRD). The univariate study demonstrated a remarkable association with progression to ESRD in our population (44% vs. 56%) RR = 13.32 (adjusted ORs (95% CI): 2.82-62.79) (p < 0.01). Progression to ESRD was frequent in our series. Early diagnosis and adequate management can delay such an evolution.

Association of torque teno virus viremia with liver fibrosis in the first year after liver transplantation.

Torque teno virus (TTV) replication is controlled by immune status, mirroring a degree of immunosuppression after solid organ transplantation. TTV viraemia (TTVv) was associated with acute cellular rejection and infection within the first year after liver transplantation (LT). Long-term data on TTV after LT and correlation with graft injury from protocol biopsies are limited. One hundred plasma samples paired with graft biopsies from a prospective single-center biorepository were analyzed. The median time post-LT was 23 months (range, 2-298). TTVv was detectable in 97%. TTVv decreased over time after LT and showed a significant decline from year 1 to later time points. Hence, TTVv correlated negatively with histologic liver fibrosis (liver allograft fibrosis and Ishak scores) and positively with the overall immunosuppression degree quantified by an immunosuppression score in the first year after LT. There was no association with dosages or trough levels of single immunosuppressants. The pharmacodynamic marker TTVv did not correlate with pharmacokinetic assessments of immunosuppression degree [calcineurin inhibitor (CNI) trough levels or immunosuppressant dosages]-our clinical gold standards to guide immunosuppressive therapy. TTVv was independently associated with histologically proven liver fibrosis after LT in the first year after LT in multivariate analysis. The independent association of histological graft fibrosis with lower TTVv in year 1 underscores that a pharmacodynamic marker would be preferable to individualize immunosuppression after LT. However, a high variability of TTVv at the low immunosuppression doses given after the first year precludes TTV as a clinically useful marker after LT in the long-term liver transplant recipients.

Optimal liver transplant procedure in progressive familial intrahepatic cholestasis type 1 treated with biliary diversion or intestinal transplantation: Lessons learned from three cases treated with different approaches.

Progressive familial intrahepatic cholestasis type 1 (PFIC1) is an autosomal recessive cholestatic liver disorder caused by ATP8B1 gene mutations. Although liver transplantation (LT) is indicated for progressive liver disease, postoperative complications, including severe diarrhea and graft steatohepatitis leading to graft loss, have been reported. The first patient had jaundice, pruritus, diarrhea, and growth retardation (weight z-score: -2.5; height z-score: -3.7). She underwent LT with total internal biliary diversion (TIBD) to the colon at 2 years of age. Graft biopsy at the 7-year follow-up examination revealed microvesicular steatosis (60%). Her diarrhea improved, and her growth failure was recovering (weight z-score: -1.0; height z-score: -1.7). The second patient underwent sequential intestine-liver transplantation at 8 years of age due to end-stage liver disease (ESLD) and short bowel syndrome caused by massive bowel resection for internal hernia after partial external biliary diversion (PEBD) at 21 months of age. She developed severe pancreatitis induced by steroid-bolus therapy for rejection after transplantation. She died 1.7 years after intestinal transplantation due to an uncontrollable pancreatic abscess and acute respiratory distress syndrome. The third patient underwent PEBD at 15 months of age and received LT with TEBD at 15 years of age due to ESLD with hepatic encephalopathy. Throughout the perioperative period, she showed no abdominal symptoms, including diarrhea and pancreatitis. Graft biopsy at the 2-year follow-up examination revealed macrovesicular steatosis (60%) with inflammation. The patients showed different outcomes. Effective therapeutic options to mitigate post-LT complications in patients with PFIC1 must be considered individually.

Time-Dependent Changes of Klotho and FGF-23 Levels after Kidney Transplantation: Role of Cold Ischemia Time, Renal Function and Graft Inflammation.

We investigated the evolution of serum klotho (s-Kl) and FGF-23 during the first two years post-kidney transplantation (KT), considering the cold ischemia time (CIT), glomerular filtration rate (GFR) and graft subclinical inflammation (SCI). We undertook a prospective, cohort, multicenter study of consecutive patients between April 2018 and January 2021 (with follow-up at 24 months). Subgroups were analyzed according to the median CIT (<14 vs. ≥14 h), the median GFR (≤40 vs. >40 mL/min/1.73 m2) and the presence of SCI at month 3. A total of 147 patients were included. s-Kl and fibroblast growth factor-23 (FGF-23) levels were measured at baseline and at months 3, 12 and 24. Graft biopsies (n = 96) were performed at month 3. All patients had low s-Kl levels at month 3. Patients with CIT < 14 h exhibited a significant increase in s-Kl at month 24. In patients with CIT ≥ 14 h, s-Kl at month 3 fell and lower s-Kl levels were seen at month 24. Patients with a GFR > 40 had a lesser decrease in s-Kl at month 3. FGF-23 fell significantly at months 3 and 12 in both GFR groups, a reduction maintained during follow-up. There were significant inter-group differences in s-Kl from months 3 to 24. CIT, GFR at 3 months and SCI were significantly associated with s-KI at month 3. A reduction in s-Kl at month 3 post-KT could be explained by longer CIT and delayed graft function as well as by impaired graft function. Early SCI may regulate s-Kl increase post-KT.

Clinical Outcome of Kidney Transplant Recipients with C1q-Binding De Novo Donor Specific Antibodies: A Single-Center Experience.

Complement activation by HLA antibodies is a key component of immune-mediated graft injury. We examined the clinical outcomes of kidney transplant recipients with complement-fixing de novo donor-specific antibodies (dnDSA) who were followed in our center. The C1q-binding ability was retrospectively assessed in 69 patients with dnDSA and mean fluorescence intensity (MFI) values > 2000 out of the 1325 kidney transplant recipients who were screened for DSA between 2015 and 2019. Luminex IgG single antigen beads (SAB)and C1q-SAB assays (One Lambda) were used. C1q-binding dnDSA was identified in 32/69 (46.4%) of the patients. Significantly higher MFI values were observed in C1q-positive DSA (18,978 versus 5840, p < 0.001). Renal graft biopsies were performed in 43 of the kidney transplant recipients (62.3%) with allograft dysfunction. Antibody-mediated rejection (ABMR) was detected in 29/43 (67.4%) of the patients. The incidence of ABMR was similar among patients with C1q-binding and non-C1q-binding DSA (51.7% vs. 48.3%, p = 0.523). Graft loss occurred in 30/69 (43.5%) of the patients at a median time of 82.5 months (IQR 45-135) from DSA detection. C1q-binding DSA was present in more patients who experienced graft loss (53.1% vs. 35.1%, p = 0.152). Higher MFI values and inferior clinical outcomes occurred in most of the kidney transplant recipients with C1q-binding dnDSA.

Association between Kidney Donor Risk Index, kidney graft function and histological changes in early post-transplant graft biopsy.

Proper assessment of donor organ quality is crucial for optimal kidney allocation and best long-term outcomes. The aim of this study was to analyze the association between the Kidney Donor Risk Index (KDRI) and histological parameters in early post-transplant graft biopsy in a Polish cohort of kidney transplant recipients. In 418 consecutive kidney transplant recipients, a histological evaluation of very early [at median 11 (9-13) post-transplant day] protocol core needle biopsy was performed and analyzed according to the Banff classification. Subjects were divided into quartiles of the KDRI value. Kidney graft function, patient and graft survival were also analyzed over a median follow-up period of 44 (26-56) months. There was a significant trend toward greater intensity of chronic histology changes along the KDRI quartiles (χ2=20.8; P<.001), including interstitial fibrosis, tubular atrophy, mesangial matrix increase and arteriolar hyalinosis. Stepwise multivariate regression analysis revealed that only higher KDRI value independently increased the severity of chronic graft injury (rpartial=0.340, P<.001). KDRI values were valuable in the determination of both early and long-term graft function. The KDRI values correlate with chronic histological changes found in early post-implantation kidney biopsies and can also be helpful in the prediction of graft outcome.

#5691 BK POLYOMAVIRUS VIREMIA AND VIRURIA ARE ASSOCIATED WITH SEVERE INFLAMMATION AND FIBROSIS IN RENAL ALLOGRAFT, BUT NOT WITH GRAFT SURVIVAL

Abstract Background and Aims Infection of the renal allograft by Polyomavirus BK (BKV) causes tubular cell injury and interstitial inflammation, which leads to subsequent interstitial fibrosis and tubular atrophy (IFTA). The presence and degree of inflammation within these areas (i-IFTA) is associated with worse outcomes in kidney transplant (KT) patients. The aim of this study was to investigate the association between BKV viremia and viruria and the presence of IFTA and i-IFTA, decline of renal function, and graft loss. Method We conducted a single-center retrospective case-control study, which included all patients who underwent an allograft biopsy between January 2018 and December 2022. All biopsies were made for-cause (allograft dysfunction with increased serum creatinine). Real-time polymerase chain reaction was used to detect and quantitate BK viral load in serum and urine samples. Patients were included if they had at least 6 months since KT and if they had serial evaluation of BKV viremia and viruria previously to the biopsy. We evaluated, in the graft biopsy, the percentage of IFTA, and also i-IFTA. Estimated glomerular filtration rate (eGFR) was obtained at baseline and 1 year after the biopsy. Graft loss was evaluated at 6 months and 1 year after the biopsy. Results Mean age of the population was 53,5 years and 67% were males. A total of 116 biopsies were performed during the studied period and 72 met the inclusion criteria. Ten percent of patients developed persistent (≥ 3 months) BKV viremia, 24% developed persistent BKV viruria, and 18% developed persistent JCV viruria. Five cases of polyomavirus-associated nephropathy were diagnosed. The other most common diagnoses were T cell-mediated rejection (24%), antibody-mediated rejection (15%), and focal segmental glomerulosclerosis (15%). In patients with persistent BKV viremia, a higher viral load had a strong positive association with the degree of i-IFTA (r=0.954; P = .001). Patients with BKV viremia and/or viruria were more likely to present more severe IFTA (≥ 40%) and i-IFTA (grade ≥2) in allograft biopsy (P = .03). Patients with higher degrees of IFTA and i-IFTA were more likely to experience graft loss 1 year after the biopsy (P = .01). There was no significant association between the presence of BKV viremia and/or viruria and the decline of eGFR, nor with the incidence of graft loss 1 year after the biopsy. In multivariable analysis adjusted for age, eGFR at the time of biopsy, the presence of donor-specific antibodies and the main diagnosis of allograft biopsy, the presence of BK viremia and/or viruria was a significant predictor of more severe IFTA and i-IFTA (P = .04). Conclusion In our population, higher BK viremia loads were associated with more extensive inflammation within areas of IFTA. Patients with BK viremia and/or viruria, independently of the main diagnosis of the biopsy, were more likely to exhibit more severe IFTA and i-IFTA in allograft biopsies, but no association with the incidence of dialysis at 1 year was shown. Longer prospective studies are needed to investigate whether BKV infection treatment/ reduction of immunosuppression can slow down fibrosis progression and minimizes i-IFTA.

#4635 CIRCULATING NEPHRIN AUTOANTIBODIES IN PATIENTS WITH POST-TRANSPLANT RECURRENCE OF PRIMARY FOCAL SEGMENTAL GLOMERULOSCLEROSIS

Abstract Background and Aims Post-transplant recurrence of primary focal segmental glomerulosclerosis (FSGS) is a major challenge in the field of nephrology and kidney transplantation. Primary FSGS is thought to be caused by circulating factors (CFs) that injure podocytes, but these factors remain unknown despite intensive efforts to identify them. Recently, one post-transplant recurrent FSGS patient with pretransplant nephrin autoantibodies was reported (Watts AJB et al, JASN 33:238, 2022). Furthermore, we reported very early post-transplant recurrence changes of podocytes and possible roles of circulating nephrin autoantibodies in a patient with FSGS recurrence (Hattori M et al, AJT 22:2478, 2022). To confirm these preliminary results, we examined the autoantibodies to nephrin and the punctate deposition of IgG colocalized with nephrin using stocked plasma samples and grafted kidney biopsy specimens of the patients with FSGS recurrence. Method This study was approved by the local Ethics Committee of Tokyo Women's Medical University (approval no. 2021-0184). The clinical and research activities reported here are consistent with the Principles of the Declaration of Istanbul as outlined in the “Declaration of Istanbul on Organ Trafficking and Transplant Tourism”. From 1989 to 2022, a total of 78 patients with FSGS underwent kidney transplantation in our institution, and 16 patients experienced post-transplant recurrence of FSGS. Since the stoked plasma samples were available in 14 out of 16 patients, these 14 patients were included in this study. All 14 patients showed immediate post-transplant recurrence and had no pathogenic variants in FSGS-related genes including NPHS1. Circulating anti-nephrin autoantibodies were measured using the ELISA methods based on the Watts's report with one modification, that is, recombinant extracellular domain of human nephrin was obtained commercially (R&amp;D systems, USA). To validate the ELISA system, circulating anti-nephrin autoantibodies were also measured in 9 genetic FSGS patients, 13 membranous nephropathy (MN) patients, 4 lupus nephritis (LN) patients, and 13 healthy controls. Dual immunofluorescence (IF) staining of nephrin and IgG and image acquisition using the two-dimensional structured illumination microscopy mode with a Nikon microscope were performed as previously reported (Hattori M et al, AJT 22:2478, 2022). Results The cut-off level of anti-nephrin antibody calculated from the results of a total 30 cases including 13 MN patients, 4 LN patients, and 13 healthy controls using Frey's formula (J Immunol Method, 1998) was 172.2 U/mL All 14 recurrent patients enrolled in this study had higher titter than the cut-off level and the mean ± SD of the anti-nephrin antibody level in these patients was 939.9 ± 261.8 U/mL. In contrast, the mean anti-nephrin antibody level in patients with genetic FSGS was 98.6 ± 77.3 U/mL, which was comparable with healthy controls. The IF staining of graft biopsy specimens showed punctate depositions of IgG colocalized with nephrin in all 14 recurrent patients. Conclusion The autoantibodies to nephrin in plasma samples and the punctate deposition of IgG colocalized with nephrin in grafted kidney biopsy specimens were observed in all 14 patients with post-transplant recurrent FSGS. Further studies in larger numbers of patients as well as in patients of other ethnicities are clearly required to confirm this surprising result; however, circulating nephrin autoantibodies could be a possible candidate for CFs in the pathogenesis of recurrent FSGS.

#5393 INFLUENCE OF CELLULAR INFLAMMATION ON THE OUTCOME OF KIDNEY TRANSPLANTATION AFTER RECURRENCE OF IGA NEPHROPATHY

Abstract Background and Aims The recurrence of IgA nephropathy (rIgAN) worsens the prognosis of renal transplantation, representing the third cause of loss in these recipients. Several variables at the time of recurrence, such as worse renal function, greater proteinuria, previous steroid withdrawal, and MEST-C histological findings have been associated with a higher risk of graft loss after recurrence. The presence of clinical or subclinical inflammation has been associated with a higher risk of kidney graft loss, but it is not precisely known how it influences the outcome of patients with rIgAN. Method A multicenter retrospective study was carried out including renal transplant recipients with biopsy-proven IgA nephropathy as the underlying disease in which the recurrence of the primary disease had been verified by means of graft biopsy and in which the Banff criteria were available or could be reviewed. Cellular inflammation was defined according to Banff scores as “t” or “i” ≥2. The main endpoint was progression to CKD stage 5 or death censored-graft loss (DCGL). Results 118 kidney transplant recipients were included with an age of 47 ± 14 years at recurrence, 80% male, with a mean time to biopsy of 65 ± 69 months and a post-transplant follow-up of 118 ± 70 months. After recurrence, 34 (28.8%) transplants were lost after 35 ± 28 months, excluding death. Using univariate Cox regression, the factors related to CKD stage 5 or graft loss were systolic blood pressure (HR 1.039, 95%CI 1.016-1.064, p = 0.001), glomerular filtration rate (HR 0.948, 95%CI 0.922-0.974, p &amp;lt;0.001), the logarithm of proteinuria (HR 15.836, 95% CI 5.504-45.565, p &amp;lt; 0.001), Oxford-C score (HR 3.490, 95% CI 2.137-5.699, p &amp;lt;0.001), interstitial fibrosis (HR 2.173, 95% CI 1.362-3.468, p = 0.001) and cellular inflammation (HR 2.458, 95% CI 1.237-4.884, p = 0.010). After multivariate analysis, cellular inflammation remained significantly related to CKD stage 5 or DCGL (HR 2.338, 95% CI 1.077-5.075, p = 0.032). independently of systolic blood pressure, glomerular filtration rate, the logarithm of proteinuria and Oxford-C score. Conclusion In addition to the previously described factors usually related to worse evolution of IgA nephropathy in the native kidney and after post-transplant recurrence, we observed that cellular inflammation influences worse evolution after rIgAN. We suggest to considering the Banff criteria for acute cellular inflammation to better understand the subsequent evolution of patients with rIgAN.

#6073 MAGNETIC RESONANCE RADIOMIC ANALYSIS FOR THE PREDICTION OF GRAFT FAILURE IN PATIENTS WITH KIDNEY TRANSPLANTATION

Abstract Background and Aims Prediction of future graft failure with non-invasive investigations is a relevant objective for transplant clinicians. We previously demonstrated a promising discrimination capacity for interstitial fibrosis / tubular atrophy (IFTA) &amp;gt;50% in kidney biopsy of a machine learning (ML) based magnetic resonance imaging (MRI) radiomic algorithm. Aim of the present study is to evaluate accuracy of MRI radiomic-based ML algorithms in predicting future graft failure. Method Single-center retrospective observational cohort study on a previously characterized cohort of kidney transplant recipients who underwent graft biopsy and graft MRI imaging within 6 months from biopsy, both on clinical indication, at the “Azienda Ospedaliero-Universitaria di Modena”, Italy, from 1/1/2012 to 1/3/2021. The primary outcome was to identify the best combination of MRI radiomic features for the prediction of graft failure during follow-up. Segmentation of renal parenchyma, cortex and medulla on MRI sequences was performed using the 3DSlicer software. Radiomic features were then extracted using an in-house software based on pyradiomics applying Wavelet and Gaussian filters. LASSO algorithm was employed to select correlated features with outcome and summarize them in a radiomic signature. Using radiomic signature alone and then merged with meaningful clinical data we trained ML-algorithms using 70% of cases for training/validation, with a 10-fold internal cross-validation, and 30% for model testing. Model performance was assessed using AUC with a 95% confidence interval (CI). Results Seventy coupled tests (63 patients) were included and randomly subdivided into a training/validation cohort (n = 50) and a test cohort (n = 20). Median follow-up was 24.73 months (interquartile range 13.64-46.57). Radiomic model had an AUC of 0.88 (95%_CI 0.70-0.97) in training and 0.57 (95%_CI 0.23-0.86) in test cohort. Radiomic-clinical mixed model had an AUC of 0.90 (95%_CI 0.73-0.98) in training and 0.66 (95%_CI 0.33-0.88) in test cohort. Conclusion We produced an MRI radiomic-based ML algorithm with good prediction ability for future graft failure in patients with kidney transplant. Given the limited number of enrolled patients, validation in larger (and ideally prospective) cohorts is required to confirm our findings. Comparison of radiomic-based ML with histological parameters (i.e., IFTA) for the prediction of graft failure in our cohort is currently under assessment.

#2566 THE EFFECT OF ULTRASOUND-GUIDED COMPRESSION IMMEDIATELY AFTER RENAL GRAFT BIOPSY ON POST BIOPSY BLEEDING

Abstract Background and Aims Renal biopsy is the gold standard for pathological diagnosis of graft dysfunction. Minor complications occur as haematuria, arteriovenous fistula (AVF) and/or small hematomas in 17% of cases. Major complications that require additional treatment as blood transfusion, surgical or interventional procedure. Bleeding may be excessive that may deteriorate ending in graft nephrectomy. Method For 6 months period, 213 renal biopsy procedure in clinically indicated patients, performed at interventional nephrology unit 144 men and 59 women, mean age 42 years old, were included. Adequate biopsies were considered showing at least ten glomeruli and 2 blood vessels. Immediate after core withdrawal, operator started ultrasound guided compression using 3-5 MHZ convex probe for 5 minutes at site of needle entrance compressing biopsy track against the graft. Post biopsy bleeding examined (peri-nephric, sub-capsular, haematuria and urinary bladder hematomas. Results Percentage of bleeding complications was compared with bleeding complications of previous 200 biopsies performed at the same centre with same operator using ordinary hand compression technique. Bleeding complications reduction by more than 60% especially percentage of perinephric hematomas. Conclusion Ultrasound guided compression technique post renal graft biopsy may reduce incidence of bleeding complications post biopsy.

Research Highlights.

Research Highlights.

Karyomegalic interstitial nephritis as a rare cause of kidney graft dysfunction: case report and review of literature

Karyomegalic interstitial nephritis (KIN) is a rare cause of chronic interstitial nephritis characterized by enlarged renal tubular epithelial nuclei. The first case of KIN reported in a kidney graft was in 2019. Here, we report the first case of KIN in 2 brothers receiving kidneys from 2 different unrelated living donors. A male kidney transplant recipient with focal segmental glomerulosclerosis as the original kidney disease presented with graft impairment and proteinuria, and graft biopsy revealed KIN. This patient had a brother who was also a kidney transplant recipient and had one episode of graft impairment and was diagnosed with KIN as well.

The Case | Crescentic glomerulonephritis in a kidney transplant recipient

A 55-year-old man was referred for acute kidney failure. He had undergone a kidney transplantation for focal segmental glomerulosclerosis 6 months before admission. Medical history consisted of hypertension, hypercholesterolemia, monoclonal gammopathy of unknown significance (IgM λ), and tertiary hyperparathyroidism secondary to chronic kidney disease. After anti-thymocyte globulin induction, the maintenance regimen consisted of azathioprine, tacrolimus, and corticosteroids. His baseline creatinine level was around 150 μmol/L, no proteinuria was detected, and a 3-month protocol graft biopsy was unremarkable. Three months after kidney transplantation, the patient developed primary cytomegalovirus infection despite valganciclovir prophylactic treatment in the setting of donor cytomegalovirus positive and recipient negative. No specific organ involvement was detected, and a ganciclovir-based regimen was started. Because of persistent viremia, 2 months after ganciclovir treatment, cytomegalovirus antiviral resistance testing was performed and a UL97 ganciclovir resistance mutation was detected. I.v. foscarnet treatment was initiated at 100 mg/kg per day.

The Landscape of Aberrant Alternative Splicing Events in Steatotic Liver Graft Post Transplantation via Transcriptome-Wide Analysis.

The application of steatotic liver graft has been increased significantly due to the severe donor shortage and prevalence of non-alcoholic fatty liver disease. However, steatotic donor livers are vulnerable to acute phase inflammatory injury, which may result in cancer recurrence. Alternative splicing events (ASEs) are critical for diverse transcriptional variants in hepatocellular carcinoma (HCC). Here, we aimed to depict the landscape of ASEs, as well as to identify the differential ASEs in steatotic liver graft and their association with tumor recurrence after transplantation. The overall portrait of intragraft transcripts and ASEs were elucidated through RNA sequencing with the liver graft biopsies from patients and rat transplant models. Various differential ASEs were identified in steatotic liver grafts. CYP2E1, ADH1A, CYP2C8, ADH1C, and HGD, as corresponding genes to the common pathways involved differential ASEs in human and rats, were significantly associated with HCC patients' survival. The differential ASEs related RNA-binding proteins (RBPs) were enriched in metabolic pathways. The altered immune cell distribution, particularly macrophages and neutrophils, were perturbated by differential ASEs. The cancer hallmarks were enriched in steatotic liver grafts and closely associated with differential ASEs. Our work identified the differential ASE network with metabolic RBPs, immune cell distribution, and cancer hallmarks in steatotic liver grafts. We verified the link between steatotic liver graft injury and tumor recurrence at post-transcriptional level, offered new evidence to explore metabolism and immune responses, and provided the potential prognostic and therapeutic markers for tumor recurrence.

Tissue Engineering Scaffolds Remotely Surveil Presymptomatic Allograft Rejection

Abstract As there is no assay to predict the risk of acute cellular allograft rejection (ACAR), clinicians rely on graft biopsy and aggressive, one-size-fits-all immunosuppression. Endomyocardial biopsy (EMB) is a flawed standard for heart transplant surveillance and diagnosing ACAR, as histological evidence of rejection inherently lags behind molecular biomarkers and suffers from variability. Noninvasive alternatives to EMB in ACAR surveillance, including gene profiling and donor-derived cell-free DNA, also measure lagging indicators of ACAR. A minimally invasive surveillance method is urgently needed to quantify early risk of rejection for minimizing biopsy and personalizing immunosuppression. We have developed porous biomaterial “scaffolds” for minimally-invasive sampling. These scaffolds amass immune cells producing biomarkers as an immunological niche. We identified predictive biomarkers of ACAR conserved in both in murine heterotopic heart transplant and skin transplant through the remote scaffold. We identified 43 highly differentially-expressed genes as organ-agnostic biomarkers of T cell-mediated rejection. These novel biomarkers differentiate between pre-symptomatic ACAR and recipients with healthy allografts, without invasive biopsy. Scaffold cell capture technology provides a leading indicator of ACAR by monitoring tissue-specific immune responses associated with allograft rejection. This implantable scaffold enables minimally invasive histological evaluation and molecular calculation of the early risk of rejection to reduce the frequency of routine EMB and personalize immune suppression that could prolong transplant life while minimizing risk. Supported by the Falk Medical Research Trust Catalyst Award and Transformational Award

Evaluation of Antithymocyte Globulin Efficacy in Reversing Refractory Graft Rejection Using Retrospective Event-Based Sequential Graft Biopsy Analysis in Living Related Donor Renal Transplant.

The main risk factor for poor graft outcomes is refractory acute rejection and its consequences. In this study, we compared the efficacy of antithymocyte globulins versus other antirejection strategies in reversing refractory acute graft rejection after living donor renal transplant. We retrospectively reviewed the records of 745 patients who received living-donor kidney transplants and experienced acute rejection episodes at Mansoura Urology and Nephrology Center in Egypt over the past 20 years. Based on the type of antirejection medication that they received, we divided patients into 2 groups, with 80 patients in the antithymocyte globulin group and 665 patients who had other antirejection strategies. By using event-based sequential graft biopsy histopathology analysis, we compared the efficacy of antithymocyte globulins in reversing refractory rejection in terms of graft and patient complications and survival. Patient survival was comparable in both groups; however, graft survival was better in the antithymocyte globulin group than in the other group; in addition, event-based sequential graft biopsies revealed a lower incidence of acute and chronic rejection episodes after treatment of severe acute rejection in the antithymocyte globulin group compared with the other group. Incidence of posttreatment complications, particularly infection and malignancy, was comparable in both groups. Our retrospective analysis of event-based sequential graft biopsy allowed us to track graft rejection resolution or worsening. Antithymocyte globulins are highly effective in reversing acute graft rejection when compared with other approaches, with no increased risk of infection or malignancy.

Kidney allograft rejection is associated with an imbalance of B cells, regulatory T cells and differentiated CD28-CD8+ T cells: analysis of a cohort of 1095 graft biopsies.

The human immune system contains cells with either effector/memory or regulatory functions. Besides the well-established CD4+CD25hiCD127lo regulatory T cells (Tregs), we and others have shown that B cells can also have regulatory functions since their frequency and number are increased in kidney graft tolerance and B cell depletion as induction therapy may lead to acute rejection. On the other hand, we have shown that CD28-CD8+ T cells represent a subpopulation with potent effector/memory functions. In the current study, we tested the hypothesis that kidney allograft rejection may be linked to an imbalance of effector/memory and regulatory immune cells. Based on a large cohort of more than 1000 kidney graft biopsies with concomitant peripheral blood lymphocyte phenotyping, we investigated the association between kidney graft rejection and the percentage and absolute number of circulating B cells, Tregs, as well as the ratio of B cells to CD28-CD8+ T cells and the ratio of CD28-CD8+ T cells to Tregs. Kidney graft biopsies were interpreted according to the Banff classification and divided into 5 biopsies groups: 1) normal/subnormal, 2) interstitial fibrosis and tubular atrophy grade 2/3 (IFTA), 3) antibody-mediated rejection (ABMR), 4) T cell mediated-rejection (TCMR), and 5) borderline rejection. We compared group 1 with the other groups as well as with a combined group 3, 4, and 5 (rejection of all types) using multivariable linear mixed models. We found that compared to normal/subnormal biopsies, rejection of all types was marginally associated with a decrease in the percentage of circulating B cells (p=0.06) and significantly associated with an increase in the ratio of CD28-CD8+ T cells to Tregs (p=0.01). Moreover, ABMR, TCMR (p=0.007), and rejection of all types (p=0.0003) were significantly associated with a decrease in the ratio of B cells to CD28-CD8+ T cells compared to normal/subnormal biopsies. Taken together, our results show that kidney allograft rejection is associated with an imbalance between immune cells with effector/memory functions and those with regulatory properties.

Renal Allograft Mucormycosis: An Unusual Case Report

Mucormycosis of the renal allograft is an extremely rare and rapidly fatal infection with an incidence of 0.2−1.2%. The major predisposing risk factors are uncontrolled diabetes mellitus, immunosuppression, anti-rejection treatment, unrelated donors, and cytomegalovirus infection. We describe a case of 27-year-old young adult patient who underwent a live-related renal allograft transplant at our centre and presented 4 weeks post-transplant with high-grade fever and rapid rise in serum creatinine. Initial cultures were repeatedly sterile, and imaging studies were normal. A few days later, he developed graft tenderness, and contrast CT abdomen revealed graft pyelonephritis. He was non-responsive to broad-spectrum antibiotics, and renal function gradually declined to anuric state. Prophylactic antifungal was added and hemodialysis was initiated. A graft biopsy was done, which revealed infiltration of the graft kidney with mucor species. After a week of antifungal treatment, graft nephrectomy was done and dual antifungals were continued. The patient initially improved symptomatically but again deteriorated with new onset fever and pain abdomen. Repeat imaging revealed a moderate intra-abdominal collection managed with per-cutaneous aspiration showing sterile growth and an abdominal drain kept in situ. Four days later, there was an accidental intra-abdominal drain expulsion with oozing of pus with blood which increased acutely with a sudden drop in blood pressure and hematocrit. Emergency exploration was done, which revealed a rent in the external iliac artery. After vascular rent repair surgery, the patient initially showed gradual improvement hemodynamically, but later, he developed superadded bacterial infection at the graft nephrectomy wound site with refractory septic shock and expired. Though early diagnosis, appropriate antifungal agents, and graft nephrectomy may improve the patient outcome, the case fatality rate of renal graft mucormycosis still remains very high.

Different biopsy techniques for different pancreas graft locations after homolateral simultaneous pancreas-kidney transplantation.

Biopsy of a transplanted pancreas is sometimes necessary in patients who have undergone simultaneous pancreas-kidney (SPK) transplantation and have elevated serum lipase and amylase concentrations. However, the risks associated with pancreatic graft biopsy are high, and the best biopsy technique for different location of pancreatic graft remains unclear. Depending on the anatomical location of the transplanted pancreas, percutaneous computed tomography (CT) combined with color Doppler-guided puncture biopsy or laparoscopic biopsy was used to obtain samples of transplanted pancreatic tissue that were shallow and deep, respectively. After SPK transplantation, 4 patients developed abnormal serum lipase and amylase concentrations and underwent pancreas graft biopsy, 1 patient underwent percutaneous CT combined with color Doppler-guided puncture biopsy, 2 patients underwent laparoscopic wedge biopsy, and 1 patient underwent laparoscopic and puncture biopsy. All biopsies were performed successfully, with no intra- or postoperative complications (e.g., bleeding, pancreatic leakage, intestinal leakage). Biopsy sampling was effective in 3 patients, including 1 case of acute pancreatic rejection, 1 case of pancreatitis, and 1 case of pancreatic plasmablastic lymphoma. Biopsy failed to retrieve samples in 1 patient with a deep pancreatic graft who underwent laparoscopic wedge biopsy. Pancreas graft biopsy is safe and feasible after SPK transplantation. In addition to the two biopsy methods mentioned, other methods can also be used. Different biopsy strategies should be formulated according to the anatomical location of the transplanted pancreas.