Clinical implications of four different nutritional indexes in patients with IgA nephropathy.

Background: Immunoglobulin A nephropathy (IgAN) is the most prevalent form of chronic kidney disease (CKD), marked by diverse pathological patterns and variable prognostic outcomes. Nutritional indexes are crucial for disease assessment and prognosis prediction. This study investigates associations between nutritional indexes and renal function in patients with IgAN. Methods: A cohort of 736 adults diagnosed with IgAN, who underwent renal biopsy at the First Hospital of Jilin University between January 2010 and October 2022, was examined. Clinical and laboratory data were reviewed, and four nutritional indexes were calculated: controlling nutritional status (CONUT) score, geriatric nutritional risk index (GNRI), body mass index (BMI), and prognostic nutritional index (PNI). Cox-proportional hazard analysis evaluated factors associated with end-stage renal disease (ESRD). Results: Patients with ESRD showed significantly lower GNRI (91.84 vs. 98.94, p < 0.001) and median PNI (41.90 vs. 46.30, p < 0.001), with higher median CONUT score (2.00 vs. 1.00, p = 0.001) compared to those without ESRD. PNI, GNRI, and CONUT scores correlated significantly with C2 in MEST-C classification. Kaplan-Meier analysis indicated increased ESRD probability in individuals with specific thresholds of PNI, GNRI, or CONUT scores. Additionally, GNRI emerged as an independent predictor of ESRD (hazard ratio: 0.963, 95% CI: 0.940-0.979, p < 0.001), along with platelet count, serum creatinine, eGFR (CKD-EPI), and triglyceride levels. Conclusion: GNRI, PNI, and CONUT scores hold potential in reflecting IgAN severity and predicting ESRD risk. GNRI especially may serve as a valuable tool for identifying high-risk individuals for ESRD in IgAN.

Enhancing prognostic guidance in renal light-chain amyloidosis: a new staging system incorporating pathological characters.

BACKGROUND: Advancements in treatment regimens have led to improved outcomes in renal Immunoglobulin light-chain amyloidosis. Nevertheless, a subset of patients may still experience renal adverse events despite achieving hematologic very good partial response or better. This discrepancy may be attributed to the deposition pattern of amyloid in renal tissue. To enhance prognostic assessment, a staging system that incorporates both pathological characteristics and clinical indicators should be developed. METHODS: Patients newly diagnosed through renal biopsy between January 1, 2017, and December 31, 2022, were included. The renal pathology of patients was evaluated according to amyloid score (AS). Risk factors for end-stage renal disease or renal progression were identified by the competing risk model, then to develop a renal staging system. The Concordance index (C-index), internal cross-validation and Decision Curve Analysis (DCA) were used to evaluate the performance of the new staging system. RESULTS: 74 patients were included, and 16 (21.6%) patients had end-stage renal disease or renal progression within 24.7 (11.9, 50.7) months. AS and estimated glomerular filtration rate (eGFR) were identified as independent risk factors and the staging system based on them, which the C-index was 0.81 (95%CI, 0.73-0.89), had greater improvement than previous staging systems. The internal cross-validation and DCA also confirmed its great clinical benefits. CONCLUSION: The AS demonstrated its prognostic significance in Chinese patients, and the novel renal staging system based on AS and eGFR may provide great prognostic guidance for these patients.

What factors influence cellular pathologists' confidence in case reporting?

Histopathology is a challenging interpretive discipline, and the level of confidence a pathologist has in their diagnosis is known to vary, which is conveyed descriptively in pathology reports. There has been little study to accurately quantify pathologists' diagnostic confidence or the factors that influence it. In this study involving sixteen pathologists from six NHS trusts, we assessed diagnostic confidence across multiple variables and four specialties. Each case was reported by four pathologists, with each pathologist reporting each case twice (on light microscopy (LM) and digital pathology (DP)). For each diagnosis, pathologists recorded their confidence on a 7-point Likert scale. This provided 16,187 diagnoses and associated confidence scores for analysis. All variables investigated were found to be significantly predictive of diagnostic confidence, except level of pathologist experience. Confidence was lower for difficult to report cases, cases where there was inter- and intra-pathologist variation in the diagnosis, and cases where the pathologist made an incorrect diagnosis. Confidence was higher, although nominally, for LM diagnoses than DP (rate ratio 1.09 (95% CI 1.01-1.18), p = 0.035), although results indicate pathologists are confident to report on DP. Lowest confidence scores were seen in areas of known diagnostic complexity and cases with quality issues. High confidence in incorrect diagnoses were almost invariably attributed to interpretive diagnostic differences which occurred across both rare and common lesions. The results highlight the value of external quality control schemes and the benefits of selective peer review when reporting.

The impact of donor diabetes on recipient postoperative complications, renal function, and survival rate in deceased donor kidney transplantation: a single-center analysis.

As the global incidence of diabetes rises and diagnoses among younger patients increase, transplant centers worldwide are encountering more organ donors with diabetes. This study examined 80 donors and 160 recipients, including 30 donors with diabetes (DD) and their 60 recipients (DDR). The control group comprised 50 non-diabetic donors (ND) and 100 recipients (NDR). We analyzed clinical, biochemical, and pathological data for both diabetic and control groups, using logistic regression to identify risk factors for delayed graft function (DGF) after kidney transplantation. Results showed that pre-procurement blood urea nitrogen levels were significantly higher in DD [18.20 ± 10.63 vs. 10.86 ± 6.92, p = 0.002] compared to ND. Renal pathological damage in DD was notably more severe, likely contributing to the higher DGF incidence in DDR compared to NDR. Although DDR had poorer renal function during the first three months post-transplant, both groups showed similar renal function thereafter. No significant differences were observed in 1-year or 3-year mortality rates or graft failure rates between DDR and NDR. Notably, according to the Renal Pathology Society (RPS) grading system, kidneys from diabetic donors with a grade > IIb are associated with significantly lower postoperative survival rates. Recipient gender [OR: 5.452 (1.330-22.353), p = 0.013] and pre-transplant PRA positivity [OR: 34.879 (7.698-158.030), p < 0.001] were identified as independent predictors of DGF in DDR. In conclusion, transplant centers may consider utilizing kidneys from diabetic donors, provided they are evaluated pathologically, without adversely impacting recipient survival and graft failure rates.

Prognostic factors and outcomes in anti-neutrophil cytoplasmic antibody-associated glomerulonephritis: A retrospective single-center study from southern China.

Objective: To investigate the prognostic factors and outcomes in patients with anti-neutrophil cytoplasmic antibody-associated glomerulonephritis (ANCA-GN) in Southern China. Methods: A retrospective analysis of medical records of patients with ANCA-GN admitted to Shenzhen Hospital of Southern Medical University and Nanfang Hospital of Southern Medical University between September 2011 and September 2021 was performed. The clinical presentation, biological, and renal pathology were collected. In addition, the risk factors for end-stage renal disease (ESRD) and short-term overall survival in patients with ANCA-GN were analyzed. Results: A total of 93 patients with ANCA-GN were included in the study. Of them, 91.4%, were perinuclear anti-neutrophil cytoplasmic antibodies (MPO-pANCA)-positive. Approximately one-quarter (24.7%) of patients had progressed to ESRD, and 7.5% died within six months. Most patients presented with hematuria (94.6%), proteinuria (78.5%), elevated serum creatinine (86.0%), anemia (90.3%), and increased erythrocyte sedimentation rate (ESR) (44.1%). The majority (94.6%) of patients presented with crescent formations at histopathological examination. Serum creatinine, hemoglobin, and Birmingham vasculitis activity score (BVAS) were all independent factors for ESRD (P<0.05). Moreover, while ANCA renal risk score (ARRS) has an impact on prognosis of nephropathy, it did not influence ESRD independently (P>0.05). The effect of Berden's histopathologic classification on ESRD has not been confirmed. Age at onset, ESR and cardiovascular involvement were all independent factors affecting short-term overall survival of patients with ANCA-GN (P<0.05). Conclusions: Serum creatinine, hemoglobin, and BVAS were all independent risk factors of ESRD, while ARRS and Berden's histopathologic classification were not. Age at onset, ESR, and cardiovascular involvement were independent risk factors for the overall six-month survival rate in patients with ANCA-GN.

Feasibility of MALDI-MSI-Based Proteomics Using Bouin-Fixed Pathology Samples: Untapping the Goldmine of Nephropathology Archives.

The application of innovative spatial proteomics techniques, such as those based upon matrix-assisted laser desorption/ionization mass spectrometry imaging (MALDI-MSI) technology, has the potential to impact research in the field of nephropathology. Notwithstanding, the possibility to apply this technology in more routine diagnostic contexts remains limited by the alternative fixatives employed by this ultraspecialized diagnostic field, where most nephropathology laboratories worldwide use bouin-fixed paraffin-embedded (BFPE) samples. Here, the feasibility of performing MALDI-MSI on BFPE renal tissue is explored, evaluating variability within the trypsin-digested proteome as a result of different preanalytical conditions and comparing them with the more standardized formalin-fixed paraffin-embedded (FFPE) counterparts. A large proportion of the features (270, 68.9%) was detected in both BFPE and FFPE renal samples, demonstrating only limited variability in signal intensity (10.22-10.06%). Samples processed with either fixative were able to discriminate the principal parenchyma regions along with diverse renal substructures, such as glomeruli, tubules, and vessels. This was observed when performing an additional "stress test", showing comparable results in both BFPE and FFPE samples when the distribution of several amyloid fingerprint proteins was mapped. These results suggest the utility of BFPE tissue specimens in MSI-based nephropathology research, further widening their application in this field.

Association between renal α-klotho and renal pathology among patients with chronic kidney disease.

INTRODUCTION: This study was designed to investigate whether renal α-klotho levels are associated with renal pathology. This is the first report on patients with chronic kidney disease (CKD). METHODS: We conducted a retrospective observational study. A total of 65 CKD patients were enrolled. Serum and renal biopsy samples were collected. Estimated glomerular filtration rate (eGFR) was examined by biochemical test. And α-klotho expressions were assessed by RT-PCR and immunohistochemistry. In addition, detailed microscopic findings were reviewed. RESULTS: Renal α-klotho levels are associated positively with eGFR, and negatively with renal pathology, including interstitial fibrosis, inflammatory cell infiltration, and tubular atrophy. CONCLUSIONS: The renal α-klotho is related to renal pathology.

Clinical and pathological features of 52 patients with glomerulonephritis with dominant C3. / C3沉积为主的肾小球肾炎52ä¾‹ä¸´åºŠä¸Žç— ç†ç‰¹å¾.

OBJECTIVES: With the in-depth study of complement dysregulation, glomerulonephritis with dominant C3 has received increasing attention, with a variety of pathologic types and large differences in symptoms and prognosis between pathologic types. This study analyzes the clinical, pathological, and prognostic characteristics of different pathological types of glomerulonephritis with dominant C3, aiming to avoid misdiagnosis and missed diagnoses. METHODS: The clinical, pathological, and follow-up data of 52 patients diagnosed as glomerulonephritis with dominant C3 by renal biopsy from June 2013 to October 2022 were retrospectively analyzed. According to the clinical feature and results of pathology, 15 patients with post-infectious glomerulonephritis (PIGN) and 37 patients with of non-infectious glomerulonephritis (N-PIGN) were classified. N-PIGN subgroup analysis was performed, and 16 patients were assigned into a C3-alone-deposition group and 21 in a C3-dominant-deposition group, or 27 in a C3 glomerulopathy (C3G) group and 10 in a non-C3 nephropathy (N-C3G) group. RESULTS: The PIGN group had lower creatinine values (84.60 µmol/L vs179.62 µmol/L, P=0.001), lower complement C3 values (0.36 g/L vs0.74 g/L, P<0.001) at biopsy, and less severe pathological chronic lesions compared with the N-PIGN group. In the N-PIGN subgroup analysis, the C3-dominant-deposition group had higher creatinine values (235.30 µmol/L vs106.70 µmol/L, P=0.004) and higher 24-hour urine protein values (4 025.62 mg vs1 981.11 mg, P=0.037) than the C3-alone-deposition group. The prognosis of kidney in the PIGN group (P=0.049), the C3-alone-deposition group (P=0.017), and the C3G group (P=0.018) was better than that in the N-PIGN group, the C3-dominant-deposition group, and the N-C3G group, respectively. CONCLUSIONS: Glomerulonephritis with dominant C3 covers a variety of pathological types, and PIGN needs to be excluded before diagnosing C3G because of considerable overlap with atypical PIGN and C3G; in addition, the deposition of C1q complement under fluorescence microscope may indicate poor renal prognosis, and relevant diagnosis, treatment, and follow-up should be strengthened.

Diagnostic Challenges and Emerging Pathogeneses of Selected Glomerulopathies.

Recent progress in glomerular immune complex and complement-mediated diseases have refined diagnostic categories and informed mechanistic understanding of disease development in pediatric patients. Herein, we discuss selected advances in 3 categories. First, membranous nephropathy antigens are increasingly utilized to characterize disease in pediatric patients and include phospholipase A2 receptor (PLA2R), Semaphorin 3B (Sema3B), neural epidermal growth factor-like 1 (NELL1), and protocadherin FAT1, as well as the lupus membranous-associated antigens exostosin 1/2 (EXT1/2), neural cell adhesion molecule 1 (NCAM1), and transforming growth factor beta receptor 3 (TGFBR3). Second, we examine advances in techniques for paraffin and light chain immunofluorescence (IF), including the former's function as a salvage technique and their necessity for diagnosis in adolescent cases of membranous-like glomerulopathy with masked IgG kappa deposits (MGMID) and proliferative glomerulonephritis with monotypic Ig deposits (PGNMID), respectively. Finally, progress in understanding the roles of complement in pediatric glomerular disease is reviewed, with specific attention to overlapping clinical, histologic, and genetic or functional alternative complement pathway (AP) abnormalities among C3 glomerulopathy (C3G), infection-related and post-infectious GN, "atypical" post-infectious GN, immune complex mediated membranoproliferative glomerulonephritis (IC-MPGN), and atypical hemolytic uremic syndrome (aHUS).

Deep learning-based glomerulus detection and classification with generative morphology augmentation in renal pathology images.

Glomerulus morphology on renal pathology images provides valuable diagnosis and outcome prediction information. To provide better care, an efficient, standardized, and scalable method is urgently needed to optimize the time-consuming and labor-intensive interpretation process by renal pathologists. This paper proposes a deep convolutional neural network (CNN)-based approach to automatically detect and classify glomeruli with different stains in renal pathology images. In the glomerulus detection stage, this paper proposes a flattened Xception with a feature pyramid network (FX-FPN). The FX-FPN is employed as a backbone in the framework of faster region-based CNN to improve glomerulus detection performance. In the classification stage, this paper considers classifications of five glomerulus morphologies using a flattened Xception classifier. To endow the classifier with higher discriminability, this paper proposes a generative data augmentation approach for patch-based glomerulus morphology augmentation. New glomerulus patches of different morphologies are generated for data augmentation through the cycle-consistent generative adversarial network (CycleGAN). The single detection model shows the F1 score up to 0.9524 in H&E and PAS stains. The classification result shows that the average sensitivity and specificity are 0.7077 and 0.9316, respectively, by using the flattened Xception with the original training data. The sensitivity and specificity increase to 0.7623 and 0.9443, respectively, by using the generative data augmentation. Comparisons with different deep CNN models show the effectiveness and superiority of the proposed approach.

Development of a Kidney Prognostic Score in a Japanese Cohort of Patients With Antineutrophil Cytoplasmic Autoantibody Vasculitis.

Introduction: Glomerulonephritis is frequent in antineutrophil cytoplasmic antibody (ANCA)-associated vasculitis (AAV) and crucial to disease outcomes. We conducted a detailed assessment of renal pathology in Japanese patients with AAV, and developed a new score that would predict renal outcome. Methods: Two hundred twenty-one patients who were diagnosed with AAV and underwent a kidney biopsy were enrolled. Data on glomerular, tubular, interstitial, and vascular lesions from kidney biopsies were analyzed; the 3 established classification and prognostic scoring systems (Berden Classification, Mayo Clinic/RPS Chronicity Score [MCCS], and ANCA Renal Risk Score [ARRS]) were validated. Further, we developed a new prognostic score by including variables relevant for Japanese patients with ANCA-glomerulonephritis. Results: Median follow-up was 60 months (interquartile range: 6-60). End-stage kidney disease (ESKD) risk prediction by the MCCS and the ARRS was confirmed. Moreover, our analysis identified 4 items with significant ESKD risk prediction capacity, namely percentage of cellular, fibrocellular, and fibrous crescents; and sclerotic glomeruli. Based on our findings, we created a score evaluating the percentage of these lesions to total glomeruli, the Percentage of ANCA Crescentic Score (PACS). The area under the receiver operating characteristic (ROC) curve evaluating PACS was 0.783. The PACS had a comparable performance as the ARRS in predicting ESKD. The optimal PACS cut-off for ESKD risk over 60 months was 43%. In addition, the percentage of cellular crescents and presence of interstitial inflammation were independent predictors of kidney function recovery. Conclusion: We developed a new score predicting renal prognosis using histopathological data of Japanese patients with ANCA-glomerulonephritis. Studies are needed to validate our results in international cohorts.

Benchmarking digital displays (monitors) for histological diagnoses: the nephropathology use case.

AIM: The digital transformation of the pathology laboratory is being continuously sustained by the introduction of innovative technologies promoting whole slide image (WSI)-based primary diagnosis. Here, we proposed a real-life benchmark of a pathology-dedicated medical monitor for the primary diagnosis of renal biopsies, evaluating the concordance between the 'traditional' microscope and commercial monitors using WSI from different scanners. METHODS: The College of American Pathologists WSI validation guidelines were used on 60 consecutive renal biopsies from three scanners (Aperio, 3DHISTECH and Hamamatsu) using pathology-dedicated medical grade (MG), professional grade (PG) and consumer-off-the-shelf (COTS) monitors, comparing results with the microscope diagnosis after a 2-week washout period. RESULTS: MG monitor was faster (1090 vs 1159 vs 1181 min, delta of 6-8%, p<0.01), with slightly better performances on the detection of concurrent diseases compared with COTS (κ=1 vs 0.96, 95% CI=0.87 to 1), but equal concordance to the commercial monitors on main diagnosis (κ=1). Minor discrepancies were noted on specific scores/classifications, with MG and PG monitors closer to the reference report (r=0.98, 95% CI=0.83 to 1 vs 0.98, 95% CI=0.83 to 1 vs 0.91, 95% CI=0.76 to 1, κ=0.93, 95% CI=077 to 1 vs 0.93, 95% CI=0.77 to 1 vs 0.86, 95% CI=0.64 to 1, κ=1 vs 0.50, 95% CI=0 to 1 vs 0.50, 95% CI=0 to 1, for IgA, antineutrophilic cytoplasmic antibody and lupus nephritis, respectively). Streamlined Pipeline for Amyloid detection through congo red fluorescence Digital Analysis detected amyloidosis on both monitors (4 of 30, 13% cases), allowing detection of minimal interstitial deposits with slight overestimation of the Amyloid Score (average 6 vs 7). CONCLUSIONS: The digital transformation needs careful assessment of the hardware component to support a smart and safe diagnostic process. Choosing the display for WSI is critical in the process and requires adequate planning.

A Case of Omeprazole-Associated Acute Interstitial Nephritis.

Acute interstitial nephritis (AIN) is characterized by an inflammatory infiltrate of the interstitium of the kidney, typically causing a decline in kidney function. Drug-induced AIN (also called allergic AIN) is a type of AIN. Common drugs associated with AIN are antibiotics, non-steroidal anti-inflammatory drugs (NSAIDs), and proton pump inhibitors (PPIs). A 59-year-old male with a history of recent laparoscopic robotic sleeve gastrectomy presented to the emergency department with five weeks of progressively worsening fatigue, nausea, and lightheadedness. Postoperatively, he was prescribed omeprazole 20 mg daily for gastric ulcer prophylaxis. His other home medications were amlodipine, atorvastatin, ursodiol, and budesonide-formoterol fumarate nebulizer. His physical examination was normal. Laboratory studies revealed elevated creatinine of 4.19 mg/dL from a baseline of 0.9 mg/dL two months ago and the presence of urine eosinophils. The etiology of this elevated creatinine was unclear, prompting CT-guided left renal biopsy. The biopsy showed diffuse interstitial inflammatory infiltration with numerous lymphocytes, a large number of neutrophils, and scattered eosinophils, consistent with the allergic type of AIN. Omeprazole was discontinued and the patient received a seven-day course of prednisone. Despite treatment, permanent renal damage occurred, and the patient's new baseline creatinine was 2.3 mg/dL. AIN caused by PPIs should be considered in the differential diagnosis of acute kidney injury (AKI). AIN can be difficult to diagnose, presenting with nonspecific symptoms, such as oliguria, malaise, nausea, and vomiting. An accurate and timely diagnosis can help prevent and treat worsening renal failure.

Animal models of lupus nephritis: the past, present and a future outlook.

Lupus nephritis (LN) is the most severe end-organ pathology in Systemic Lupus Erythematosus (SLE). Research has enhanced our understanding of immune effectors and inflammatory pathways in LN. However, even with the best available therapy, the rate of complete remission for proliferative LN remains below 50%. A deeper understanding of the resistance or susceptibility of renal cells to injury during the progression of SLE is critical for identifying new targets and developing effective long-term therapies. The complex and heterogeneous nature of LN, combined with the limitations of clinical research, make it challenging to investigate the aetiology of this disease directly in patients. Hence, multiple murine models resembling SLE-driven nephritis are utilised to dissect LN's cellular and genetic mechanisms, identify therapeutic targets, and screen novel compounds. This review discusses commonly used spontaneous and inducible mouse models that have provided insights into pathogenic mechanisms and long-term maintenance therapies in LN.

[Urinary protein and renal pathological features in children with immunoglobulin A vasculitis with nephritis and hypercoagulability]. / 儿童IgAè¡€ç®¡ç‚Žè‚¾ç‚Žä¼´é«˜å‡çŠ¶æ€çš„å°¿è›‹ç™½å’Œè‚¾è„ç— ç†ç‰¹å¾åˆ†æž.

OBJECTIVES: To study the association of hypercoagulability with urinary protein and renal pathological damage in children with immunoglobulin A vasculitis with nephritis (IgAVN). METHODS: Based on the results of coagulation function, 349 children with IgAVN were divided into a hypercoagulability group consisting of 52 children and a non-hypercoagulability group consisting of 297 children. Urinary protein and renal pathological features were compared between the two groups, and the factors influencing the formation of hypercoagulability in children with IgAVN were analyzed. RESULTS: Compared with the non-hypercoagulability group, the hypercoagulability group had significantly higher levels of urinary erythrocyte count, 24-hour urinary protein, urinary protein/creatinine, urinary immunoglobulin G/creatinine, and urinary N-acetyl-ß-D-glucosaminidase (P<0.05). The hypercoagulability group also had a significantly higher proportion of children with a renal pathological grade of III-IV, diffuse mesangial proliferation, capillary endothelial cell proliferation, or >25% crescent formation (P<0.05). The multivariate logistic regression analysis showed that capillary endothelial cell proliferation and glomerular crescent formation >25% were associated with the formation of hypercoagulability in children with IgAVN (P<0.05). CONCLUSIONS: The renal injury in IgAVN children with hypercoagulability is more severe, with greater than 25% crescent formation and increased proliferation of glomerular endothelial cells being important contributing factors that exacerbate the hypercoagulable state in IgAVN.

Atypical Anti-Glomerular Basement Membrane Nephritis: A Case Series From the French Nephropathology Group.

RATIONALE & OBJECTIVE: Atypical anti-glomerular basement membrane (GBM) nephritis is characterized by a bright linear immunoglobulin staining along the GBM by immunofluorescence without a diffuse crescentic glomerulonephritis nor serum anti-GBM antibodies by conventional enzyme-linked immunosorbent assay (ELISA). We characterized a series of patients with atypical anti-GBM disease. STUDY DESIGN: Case series. SETTING & PARTICIPANTS: Patients identified by the French Nephropathology Group as having atypical anti-GBM nephritis between 2003 and 2022. FINDINGS: Among 38 potential cases, 25 were included, of whom 14 (56%) were female and 23 (92%) had hematuria. The median serum creatinine at diagnosis was 150 (IQR, 102-203) µmol/L and median urine protein-creatinine ratio (UPCR) was 2.4 (IQR, 1.3-5.2) g/g. Nine patients (36%) had endocapillary proliferative glomerulonephritis (GN), 4 (16%) had mesangial proliferative GN, 4 (16%) had membranoproliferative GN, 2 (8%) had pure and focal crescentic GN, 1 (4%) had focal segmental glomerulosclerosis, and 5 had glomeruli that were unremarkable on histopathology. Nine patients (36%) had crescents, involving a median of 9% of glomeruli. Bright linear staining for IgG was seen in 22 cases (88%) and for IgA in 3 cases (12%). The 9 patients (38%) who had a monotypic staining pattern tended to be older with less proteinuria and rarely had crescents. Kidney survival rate at 1 year was 83% and did not appear to be associated with the light chain restriction. LIMITATIONS: Retrospective case series with a limited number of biopsies including electron microscopy. CONCLUSIONS: Compared with typical anti-GBM disease, atypical anti-GBM nephritis frequently presents with an endocapillary or mesangial proliferative glomerulonephritis pattern and appears to have a slower disease progression. Further studies are needed to fully characterize its pathophysiology and associated clinical outcomes. PLAIN-LANGUAGE SUMMARY: Atypical anti-glomerular basement membrane (GBM) nephritis is characterized histologically by bright linear immunoglobulin staining along the GBM without diffuse crescentic glomerulonephritis or circulating anti-GBM antibodies. We report a case series of 25 atypical cases of anti-GBM nephritis in collaboration with the French Nephropathology Group. Compared with typical anti-GBM disease, we observed a slower disease progression. Patients frequently presented with heavy proteinuria and commonly had evidence of endocapillary or mesangial proliferative glomerulonephritis. About half of the patients displayed a monotypic immune staining pattern; they tended to be older, with less proteinuria, and commonly without glomerular crescents in biopsy specimens. No concomitant circulating monoclonal gammopathy was detected. Further studies are needed to fully characterize its pathophysiology and associated clinical outcomes.

Diffusion-weighted, intravoxel incoherent motion, and diffusion kurtosis tensor MR imaging in chronic kidney diseases: Correlations with histology.

OBJECTIVES: To probe the correlations of parameters derived from standard DWI and its extending models including intravoxel incoherent motion (IVIM), diffusion tensor imaging (DTI), and diffusion kurtosis imaging (DKI) with the pathological and functional alterations in CKD. MATERIAL AND METHODS: Seventy-nine CKD patients with renal biopsy and 10 volunteers were performed with DWI, IVIM, diffusion kurtosis tensor imaging (DKTI) scanning. Correlations between imaging results and the pathological damage [glomerulosclerosis index (GSI) and tubulointerstitial fibrosis index (TBI)], as well as eGFR, 24 h urinary protein and Scr) were evaluated.CKD patients were divided into 2 groups: group 1: both GSI and TBI scores <2 points (61 cases); group 2: both GSI and TBI scores ≥2 points (18 cases). RESULTS: There were significant difference in cortical and medullary MD, and cortical D among 3 groups and between group 1 and 2. Cortical and medullary MD, cortical D, and medullary FA were negatively correlated with GSI score (r = -0.322 to -0.386, P < 0.05). Cortical and medullary MD and D, medullary FA were also negatively correlated with TBI score (r = -0.257 to -0.395, P < 0.05). These parameters were all correlated with eGFR and Scr. Cortical MD and D showed the highest AUC of 0.790 and 0.745 in discriminating mild and moderate-severe glomerulosclerosis and tubular interstitial fibrosis, respectively. CONCLUSIONS: The corrected diffusion-related indices, including cortical and medullary D and MD, as well as medullary FA were superior to ADC, perfusion-related and kurtosis indices for evaluating the severity of renal pathology and function in CKD patients.

A large-scale retrospective study enabled deep-learning based pathological assessment of frozen procurement kidney biopsies to predict graft loss and guide organ utilization.

Lesion scores on procurement donor biopsies are commonly used to guide organ utilization for deceased-donor kidneys. However, frozen sections present challenges for histological scoring, leading to inter- and intra-observer variability and inappropriate discard. Therefore, we constructed deep-learning based models to recognize kidney tissue compartments in hematoxylin & eosin-stained sections from procurement needle biopsies performed nationwide in years 2011-2020. To do this, we extracted whole-slide abnormality features from 2431 kidneys and correlated with pathologists' scores and transplant outcomes. A Kidney Donor Quality Score (KDQS) was derived and used in combination with recipient demographic and peri-transplant characteristics to predict graft loss or assist organ utilization. The performance on wedge biopsies was additionally evaluated. Our model identified 96% and 91% of normal/sclerotic glomeruli respectively; 94% of arteries/arterial intimal fibrosis; 90% of tubules. Whole-slide features of Sclerotic Glomeruli (GS)%, Arterial Intimal Fibrosis (AIF)%, and Interstitial Space Abnormality (ISA)% demonstrated strong correlations with corresponding pathologists' scores of all 2431 kidneys, but had superior associations with post-transplant estimated glomerular filtration rates in 2033 and graft loss in 1560 kidneys. The combination of KDQS and other factors predicted one- and four-year graft loss in a discovery set of 520 kidneys and a validation set of 1040 kidneys. By using the composite KDQS of 398 discarded kidneys due to "biopsy findings", we suggest that if transplanted, 110 discarded kidneys could have had similar survival to that of other transplanted kidneys. Thus, our composite KDQS and survival prediction models may facilitate risk stratification and organ utilization while potentially reducing unnecessary organ discard.

Severe glomerular fibrin thrombosis in a dog.

Here, we present a case of severe glomerular fibrin thrombosis in a dog with lymphoma. A 3-year-old neutered male Chihuahua presented with acute kidney injury, hypoalbuminemia, and transudate ascites. The dog showed symmetric enlargement of the spleen, which was diagnosed as B-cell lymphoma based on cytology and polymerase chain reaction tests. The dog died after intensive care, and the kidneys were removed for histopathological examination. Light microscopy, immunofluorescence, and electron microscopy analyses were performed for renal pathology; however, the findings did not support the evidence of protein-losing nephropathy. Instead, the endocapillary accumulation of fibrin thrombi was prominent in most glomeruli. A diagnosis of severe glomerular fibrin thrombosis was established, and hypoalbuminemia was considered the underlying cause of kidney damage.