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Kidney fibrosis constitutes the shared final pathway of nearly all chronic nephropathies, but biomarkers for the non-invasive assessment of kidney fibrosis are currently not available. To address this, we characterize five candidate biomarkers of kidney fibrosis: Cadherin-11 (CDH11), Sparc-related modular calcium binding protein-2 (SMOC2), Pigment epithelium-derived factor (PEDF), Matrix-Gla protein, and Thrombospondin-2. Gene expression profiles in single-cell and single-nucleus RNA-sequencing (sc/snRNA-seq) datasets from rodent models of fibrosis and human chronic kidney disease (CKD) were explored, and Luminex-based assays for each biomarker were developed. Plasma and urine biomarker levels were measured using independent prospective cohorts of CKD: the Boston Kidney Biopsy Cohort, a cohort of individuals with biopsy-confirmed semiquantitative assessment of kidney fibrosis, and the Seattle Kidney Study, a cohort of patients with common forms of CKD. Ordinal logistic regression and Cox proportional hazards regression models were used to test associations of biomarkers with interstitial fibrosis and tubular atrophy and progression to end-stage kidney disease and death, respectively. Sc/snRNA-seq data confirmed cell-specific expression of biomarker genes in fibroblasts. After multivariable adjustment, higher levels of plasma CDH11, SMOC2, and PEDF and urinary CDH11 and PEDF were significantly associated with increasing severity of interstitial fibrosis and tubular atrophy in the Boston Kidney Biopsy Cohort. In both cohorts, higher levels of plasma and urinary SMOC2 and urinary CDH11 were independently associated with progression to end-stage kidney disease. Higher levels of urinary PEDF associated with end-stage kidney disease in the Seattle Kidney Study, with a similar signal in the Boston Kidney Biopsy Cohort, although the latter narrowly missed statistical significance. Thus, we identified CDH11, SMOC2, and PEDF as promising non-invasive biomarkers of kidney fibrosis.

Proliferative glomerulonephritis with monoclonal IgG deposits (PGNMID) is a glomerular disease defined by non-organized glomerular deposits of heavy and light chain–restricted immunoglobulin and is rarely reported in children. We characterized a series of nine pediatric patients from two academic centers with biopsy-proven PGNMID and additionally describe two patients with monotypic IgG in the setting of IgM deposition. Each patient presented with hematuria and/or proteinuria; however, only five had elevated serum creatinine. Prodromal or concurrent infection was identified in six patients, low C3 in five, and alternate complement pathway gene variants in two. No monoclonal serum proteins were identified in five tested patients. Seven patients had monotypic deposits composed of IgG3-λ, two showed IgG3-κ, and one each IgG1 and IgG3 with lambda dominance in the setting of IgM deposition. The glomerular pattern was predominantly mesangial proliferative or membranoproliferative glomerulonephritis (MPGN). Treatment and outcomes were variable; four patients have recent PGNMID diagnoses and therefore minimal follow up, one had relatively stable kidney function for over a decade, and six experienced kidney failure, with four receiving transplants. Recurrent deposits of the same isotype were identified in five of six transplanted kidneys, corresponding to three of four transplanted patients. One of these patients developed PGNMID recurrences in three separate kidney allografts over a 20-year disease course. Our study emphasizes the need for upfront IgG subclass investigation in pediatric mesangial or MPGN with IgG deposition and monotypic or biased light-chain staining. Furthermore, this pediatric experience suggests expanded pathogenic considerations in PGNMID.

Background T helper (Th) type 17 and Th2 cells mediate psoriasis and eczema, respectively. Some dermatoses exhibit overlapping clinicopathologic features, and their immunopathology is relatively unexplored. Objective To determine whether Th17 and Th2 subsets and interleukin (IL) 36 and β-defensin 2 (BD-2) markers of IL-17 signaling expression can discriminate between biopsy samples of psoriasis and eczematous/spongiotic dermatitis and to use those markers to immunophenotype cases with clinicopathologic overlap. Methods A retrospective study was performed on biopsy samples of psoriasis, eczema/spongiotic dermatitis, sebopsoriasis, tumor necrosis factor α inhibitor–associated psoriasiform dermatitis, and ambiguous cases diagnosed as spongiotic psoriasiform dermatitis. Dual CD4/GATA3 and CD4/RORC, IL-36, and BD-2 immunohistochemistry was performed. Results IL-36 and BD-2 were strongly expressed in biopsy samples of psoriasis compared with eczema/spongiotic dermatitis. No significant differences were observed in the percentages of Th2 and Th17 cells between disease types. Strong expression of IL-36 and BD-2 was observed in a subset of spongiotic psoriasiform dermatitis, sebopsoriasis, and tumor necrosis factor α inhibitor–associated psoriasiform dermatitis biopsy samples. Limitations This was an exploratory study with a small sample size. No multiple testing adjustment was done. Clinical follow-up was limited. Conclusions In cases with clinicopathologic overlap between psoriasis and spongiotic dermatitis, IL-36, and to a lesser extent BD-2, may be used to assess for a psoriasis-like/IL-17 phenotype, which could inform therapeutic clinical decisions.

Conversion of glass slides to digital images is necessary to capitalize on advances in computational pathology and could potentially transform our approach to primary diagnosis, research, and medical education. Most slide scanners have a limited maximum scannable area and utilize proprietary tissue detection algorithms to selectively scan regions that contain tissue, allowing for increased scanning speed and reduced file size compared to scanning the entire slide at high resolution. However, very small and faintly stained tissue fragments may not be recognized by these algorithms, leading to loss of fidelity in the digital image compared to the glass slides. Cavitron ultrasonic surgical aspirator (CUSA) is frequently used in brain tumor resections, resulting in highly fragmented specimens that are used for primary diagnosis. Here we evaluated the rate of loss of fidelity in 296 digital images from 40 CUSA‐resected brain tumors scanned using a Philips Ultra Fast Scanner. Overall, 54% of the slides (at least one from every case) showed loss of fidelity, with at least one tissue fragment not scanned at high resolution. The majority of the missed tissue fragments were small (, Loss of fidelity in scanned whole‐slide images (WSI) is frequent for brain tumors resected using the cavitron ultrasonic surgical aspirator (CUSA), and cannot always be appreciated without review of the glass slide.

Chronic kidney disease (CKD) and acute kidney injury (AKI) are common, heterogeneous, and morbid diseases. Mechanistic characterization of CKD and AKI in patients may facilitate a precision medicine approach to prevention, diagnosis, and treatment. The Kidney Precision Medicine Project aims to ethically and safely obtain kidney biopsies from participants with CKD or AKI, create a reference kidney atlas, and characterize disease subgroups to stratify patients based on molecular features of disease, clinical characteristics, and associated outcomes. An additional aim is to identify critical cells, pathways, and targets for novel therapies and preventive strategies. This project is a multicenter prospective cohort study of adults with CKD or AKI who undergo a protocol kidney biopsy for research purposes. This investigation focuses on kidney diseases that are most prevalent and therefore substantially burden the public health, including CKD attributed to diabetes or hypertension and AKI attributed to ischemic and toxic injuries. Reference kidney tissues (for example, living kidney donor biopsies) will also be evaluated. Traditional and digital pathology will be combined with transcriptomic, proteomic, and metabolomics analysis of the kidney tissue as well as deep clinical phenotyping for supervised and unsupervised subgroup analysis and systems biology analysis. Participants will be followed prospectively for ten years to ascertain clinical outcomes. Cell types, locations, and functions will be characterized in health and disease in an open, searchable, online kidney tissue atlas. All data from the Kidney Precision Medicine Project will be made readily available for broad use by scientists, clinicians, and patients.

Kidney Precision Medicine Project (KPMP) is building a spatially-specified human tissue atlas at the single-cell resolution with molecular details of the kidney in health and disease. Here, we describe the construction of an integrated reference tissue map of cells, pathways and genes using unaffected regions of nephrectomy tissues and undiseased human biopsies from 55 subjects. We use single-cell and -nucleus transcriptomics, subsegmental laser microdissection bulk transcriptomics and proteomics, near-single-cell proteomics, 3-D nondestructive and CODEX imaging, and spatial metabolomics data to hierarchically identify genes, pathways and cells. Integrated data from these different technologies coherently describe cell types/subtypes within different nephron segments and interstitium. These spatial profiles identify cell-level functional organization of the kidney tissue as indicative of their physiological functions and map different cell subtypes to genes, proteins, metabolites and pathways. Comparison of transcellular sodium reabsorption along the nephron to levels of mRNAs encoding the different sodium transporter genes indicate that mRNA levels are largely congruent with physiological activity.This reference atlas provides an initial framework for molecular classification of kidney disease when multiple molecular mechanisms underlie convergent clinical phenotypes.

The elusive nature of assessing immunological processes in situ in organ transplantation is one of the major impediments to improve diagnostics and treatment. Here, we present a proof-of-concept study using multiplexed in situ hybridization (ISH) (RNAscope) to detect low-abundance cytokines in formalin-fixed paraffin-embedded (FFPE) human transplant kidney biopsies in combination with immunofluorescence (IF) for cell phenotyping. We show that a multiplex IF and ISH (mIFISH) assay is feasible to identify the cellular source of cytokines and chemokines (tumor necrosis factor-α, interferon-γ, and CXCL9) in FFPE transplant kidney biopsies and that quantification of the mRNA and protein signal is also possible at single-cell resolution in the context of tissue complexity. Furthermore, the mIFISH assay allows precise quantitative assessment of tubulitis, one of the key morphological correlates of alloimmune injury. Simultaneous in situ identification and quantification of multiple cellular phenotypes and mRNA expression of proinflammatory cytokines in FFPE tissues offer a novel insight into the biology of alloimmune injury in kidney transplantation and may contribute to improved diagnostic accuracy and patient care.

We present here the case of a 39-year-old man with metastatic pancreatic carcinoma receiving chemotherapy with the combination of gemcitabine and nab-paclitaxel as part of a clinical trial. Despite an impressive response to therapy, he ultimately developed profound anasarca, renal insufficiency, progressive cytopenias, and malignant hypertension 6 months into his treatment course. The diagnosis of gemcitabine-associated thrombotic microangiopathy (G-TMA) was made based on renal biopsy, and receipt of the anti-C5 monoclonal antibody eculizumab proved successful at reversing his deteriorating clinical course and improving his laboratory parameters. This case illustrates the importance of recognizing this rare but serious complication, and highlights one potential therapeutic option that can be used in the appropriate clinical context.

BackgroundThe role of the soluble urokinase plasminogen activator receptor (suPAR) in focal segmental glomerulosclerosis (FSGS) as the circulating factor or as a predictor of recurrence after transplantation remains controversial. Previously published studies in mice and isolated podocytes produced conflicting results on the effect of suPAR on podocyte injury, effacement of foot processes, and proteinuria. These discordant results were in part due to diverse experimental designs and different strains of mice. The aim of our study was to determine the reasons for the inconsistencies of the previous studies results with suPAR by using uniform methods and studies in different strains of mice.MethodsWe utilized a primary culture of human podocytes and 2 mouse models, the wild type (WT) and the urokinase plasminogen activator receptor (uPAR) KO (uPAR), in an attempt to resolve the reported conflicting results.ResultsIn both WT and uPAR mouse models, injection of recombinant uPAR, even at a high dose (100 μg), did not induce proteinuria, effacement of podocytes, or disruption of the cytoskeleton. Injection of suPAR resulted in its deposition exclusively in the glomerular endothelial cells and not in the podocytes of WT mice and was not detected at the uPAR KO mice. Kidneys from patients with recurrent FSGS had negative immunostaining for uPAR. We also evaluated the effect of recombinant uPAR on primary culture of human podocytes. uPAR did not result in podocytes damage.ConclusionssuPAR by itself is not the cause for direct podocyte injury, in vitro or in vivo. These findings suggest a more complex and still poorly understood role of suPAR in FSGS.

Background: There is an urgent need to develop and implement low cost, high-throughput standardized methods for routine molecular assessment of transplant biopsies. Given the vast archive of formalin-fixed and paraffin-embedded (FFPE) tissue blocks in transplant centers, a reliable protocol for utilizing this tissue bank for clinical validation of target molecules as predictors of graft outcome over time, would be of great value. Methods: We designed and optimized assays to quantify 19 target genes, including previously reported set of tissue common rejection module (tCRM) genes. We interrogated their performance for their clinical utility for detection of graft rejection and inflammation by analyzing gene expression microarrays analysis of 163 renal allograft biopsies, and subsequently validated in 40 independent FFPE archived kidney transplant biopsies at a single center. Results: A QPCR (Fluidigm) and a barcoded oligo-based (NanoString) gene expression platform were compared for evaluation of amplification of gene expression signal for 19 genes from degraded RNA extracted from FFPE biopsy sections by a set protocol. Increased expression of the selected 19 genes, that reflect a combination of specific cellular infiltrates (8/19 genes) and a graft inflammation score (11/19 genes which computes the tCRM score allowed for segregation of kidney transplant biopsies with stable allograft function and normal histology from those with histologically confirmed acute rejection (AR; p = 0.0022, QPCR; p = 0.0036, barcoded assay) and many cases of histological borderline inflammation (BL). Serial biopsy shaves used for gene expression were also processed for in-situ hybridization (ISH) for a subset of genes. ISH confirmed a high degree of correlation of signal amplification and tissue localization. Conclusions: Target gene expression amplification across a custom set of genes can identify AR independent of histology, and quantify inflammation from archival kidney transplant biopsy tissue, providing a new tool for clinical correlation and outcome analysis of kidney allografts, without the need for prospective kidney biopsy biobanking efforts.

Allograft rejection is a major concern in kidney transplantation. Inflammatory processes in patients with kidney allografts involve various patterns of immune cell recruitment and distributions. Lymphoid aggregates (LAs) are commonly observed in patients with kidney allografts and their presence and localization may correlate with severity of acute rejection. Alongside with other markers of inflammation, LAs assessment is currently performed by pathologists manually in a qualitative way, which is both time consuming and far from precise. Here we present the first automated method of identifying LAs and measuring their densities in whole slide images of transplant kidney biopsies. We trained a deep convolutional neural network based on U-Net on 44 core needle kidney biopsy slides, monitoring loss on a validation set (n=7 slides). The model was subsequently tested on a hold-out set (n=10 slides). We found that the coarse pattern of LAs localization agrees between the annotations and predictions, which is reflected by high correlation between the annotated and predicted fraction of LAs area per slide (Pearson R of 0.9756). Furthermore, the network achieves an auROC of 97.78 ± 0.93% and an IoU score of 69.72 ± 6.24 % per LA-containing slide in the test set. Our study demonstrates that a deep convolutional neural network can accurately identify lymphoid aggregates in digitized histological slides of kidney. This study presents a first automatic DL-based approach for quantifying inflammation marks in allograft kidney, which can greatly improve precision and speed of assessment of allograft kidney biopsies when implemented as a part of computer-aided diagnosis system.

Lymphocytic bronchitis (LB) precedes chronic lung allograft dysfunction (CLAD). The relationships of LB (classified here as Endobronchial or E-grade rejection) to small airway (A- and B-grade) pathologies are unclear. We hypothesized that gene signatures common to allograft rejection would be present in LB. We studied LB in two partially overlapping lung transplant recipient cohorts: Cohort 1 included large airway brushes (6 LB cases and 18 post-transplant referents). Differential expression using DESeq2 was used for pathway analysis and to define an LB-associated metagene. In Cohort 2, eight biopsies for each pathology subtype were matched with pathology-free biopsies from the same subject (totaling 48 samples from 24 subjects). These biopsies were analyzed by multiplexed digital counting of immune transcripts. Metagene score differences were compared by paired t-tests. Compared to referents in Cohort 1, LB demonstrated upregulation of allograft rejection pathways, and upregulated genes in these cases characterized an LB-associated metagene. We observed statistically increased expression in Cohort 2 for this LB-associated metagene and four other established allograft rejection metagenes in rejection vs. paired non-rejection biopsies for both E-grade and A-grade subtypes, but not B-grade pathology. Gene expression-based categorization of allograft rejection may prove useful in monitoring lung allograft health. This article is protected by copyright. All rights reserved.

Purpose Rejection and infection can be antecedents of chronic lung allograft dysfunction (CLAD), the major limitation to long term survival for lung transplant recipients. BAL cytology is routinely performed but recently some have advocated abandoning this practice because of the low diagnostic yield. We hypothesized that inflammation observed on BAL cytology would predict CLAD risk. Methods We categorized diagnostic findings on BAL cytology between 2012 and 2019. Bronchoscopy indication, infection treatment, BAL and biopsy results, and CLAD-free survival were abstracted from medical records. Cytology associations with clinical outcomes were compared using generalized-estimating equation-adjusted logistic regression. The association between BAL inflammation and CLAD or death were determined using time-dependent Cox proportional hazards models adjusted for age, gender, diagnosis, lung allocation score, and transplant type. Results We evaluated 3,578 cytology reports from 491 subjects. Inflammation was the most common finding (6.4%), followed by fungi (5.2%). There were 5 cases of malignancy and 2 cases of CMV. Inflammation on BAL cytology was more common in procedures performed for symptoms, associated with antimicrobial initiation (a proxy for clinically significant infection), associated with acute rejection, and linked to increased BAL neutrophil and lymphocyte concentrations (Figure 1A). Inflammation on BAL cytology was present for 32% of subjects on at least one sample, more frequent around the time of CLAD onset, and associated a 2.6-fold hazard ratio (CI 1.2-5.3) for CLAD or death (Figure 1B). However, this association was not significant after adjusting for BAL cell counts and acute rejection. Conclusion Inflammation on BAL cytology specimens is clinically significant, suggesting acute rejection or infection and increased risk of CLAD or death. However, other indicators of allograft inflammation can substitute for some of the information provided by BAL cytology.

Little is known about the morphology and clinical relevance of arteritis in renal allograft biopsies with transplant glomerulopathy. We retrospectively reviewed the morphologic findings and clinical course of 59 patients with cg, 16 of which featured concurrent arteritis (fibrosing intimal arteritis with luminal narrowing in 15, and acute intimal arteritis in 1 case). Fifteen out of the 16 cases with arteritis fulfilled the morphological diagnostic criteria for chronic active antibody-mediated rejection, and 11 cases with arteritis showed morphological evidence of concurrent, ongoing T-cell-mediated alloimmune response (acute T-cell-mediated rejection in 5, borderline changes in 6 cases). Further, the Banff grades of interstitial inflammation in scarred and nonscarred cortex, total cortical inflammation, and arterial luminal narrowing were significantly higher in biopsies with arteritis. By immunohistochemistry, T-lymphocyte predominance over macrophages was found in the intimal infiltrates in 14 out of 16 cases, and cytotoxic T-lymphocytes were identified among intimal mononuclears in 10 cases. Patients with arteritis demonstrated a significantly shorter renal survival (7.5 vs. 29 months). In conclusion, T-cell-mediated mechanisms could play a role in the development of arteritis concurrent with cg. However, this finding does not exclude the possibility that antibody-mediated rejection can also contribute to the evolution of the lesion. Importantly, the lesion carries negative prognostic value likely via severe arterial luminal narrowing.

Lenalidomide, a thalidomide analogue, is an immunomodulatory drug currently used as a chemotherapeutic agent in treating certain hematologic malignancies, including multiple myeloma. The antineoplastic effect of lenalidomide may be due to its ability to modulate different components of the immune system as well as its antiangiogenic, antiproliferative, and direct cytotoxic activity. Given its immunomodulatory effects, lenalidomide may potentially elicit unintended immune activity against allografts in solid organ transplant recipients. Here, we present a case of a renal transplant recipient who developed multiple myeloma after transplantation and was treated with the use of lenalidomide, which precipitated severe acute T-cell-mediated rejection. Lenalidomide was thought to be causative, and after cessation of the drug her renal function stabilized.

Early subclinical inflammation in kidney transplants is associated with later graft fibrosis and dysfunction. Regulatory T cells (Tregs) can reverse established inflammation in animal models. We conducted a pilot safety and feasibility trial of autologous Treg cell therapy in three kidney transplant recipients with subclinical inflammation noted on 6-month surveillance biopsies. Tregs were purified from peripheral blood and polyclonally expanded ex vivo using medium containing deuterated glucose to label the cells. All patients received a single infusion of ~320 × 106 (319, 321, and 363.8 × 106 ) expanded Tregs. Persistence of the infused Tregs was tracked. Graft inflammation was monitored with follow-up biopsies and urinary biomarkers. Nearly 1 × 109 (0.932, 0.956, 1.565 × 109 ) Tregs were successfully manufactured for each patient. There were no infusion reactions or serious therapy-related adverse events. The infused cells demonstrated patterns of persistence and stability similar to those observed in non-immunosuppressed subjects receiving the same dose of Tregs. Isolation and expansion of Tregs is feasible in kidney transplant patients on immunosuppression. Infusion of these cells was safe and well tolerated. Future trials will test the efficacy of polyclonal and donor alloantigen-reactive Tregs for the treatment of inflammation in kidney transplants.

Immunotactoid deposits are defined by their ultrastructural appearance and are characterized by microtubular or cylindrical structures typically measuring greater than 30 nm in diameter. Although a rare entity, immunotactoid deposition most often manifests as immunotactoid glomerulopathy and is associated with underlying lymphoplasmacytic disorders. Corneal immunotactoid deposition known as immunotactoid keratopathy has also been reported in patients with paraproteinemia. Here, we describe the first reported case of immunotactoid deposition in the stomach. The deposits were composed solely of kappa immunoglobulin light chains without significant lambda light chain or immunoglobulin heavy chain components. The patient displayed no renal signs or symptoms, and additional thorough clinical examination failed to detect any evidence of a paraproteinemia or plasma cell dyscrasia. Thus, the gastric immunotactoid deposits in this case appear to be an isolated finding of light chain deposition, of which the significance and etiology are unclear.

The morphology of focal segmental glomerulosclerosis (FSGS) includes collapsing, cellular, and sclerosing forms. The Columbia Working Classification of FSGS divides these into collapsing (COLL), cellular (CELL), tip lesion (TIP), perihilar (PH), and not otherwise specified (NOS) morphologic forms. This study examined the ability of renal pathologists to classify FSGS using single light microscopic images of glomeruli as a uniform data set. Sixty-one digital images of individual glomeruli with FSGS, stained by periodic acid-Schiff or Jones methenamine silver methods, were classified independently by six specialist renal pathologists. Diagnostic consistency was quantified using the kappa statistic for nominal categories. Agreement for 366 diagnoses by six observers was 75.2 % with a kappa value of 0.676. Six of six observers agreed in 31 of 61 cases (50.8 %) and four or more in 53 cases (86.9 %). Respective kappa values ranged from moderate to good: COLL 0.77, CELL 0.53, TIP 0.76, PH 0.84, and NOS 0.60. Capillary retraction with lobular expansion, hypercellularity, and sclerosis in the same glomerular segments, and the location of segmental lesions were sources of diagnostic inconsistency. The morphologic forms of FSGS defined by the Columbia system are reproducible between observers and have a low probability of confusion between forms. Individual glomeruli may have overlapping features of more than one form of FSGS.

Cytomegalovirus (CMV) disease is a leading cause of infectious morbidity and mortality in patients with a kidney transplant. Before the advent of specific prophylaxis and therapy, more than half of the patients who had not been exposed to CMV prior to kidney transplantation developed primary disease and ~20% of patients with prior evidence of exposure developed reactivation disease [1]. Mortality estimates from CMV disease exceeded 30% [2]. Although use of prophylaxis or preemptive treatment of detectable viral load has drastically reduced its burden, CMV remains a common clinical problem with a wide variety of presentations. To highlight the importance of clinical vigilance for CMV even in the current era of effective prophylaxis, we describe two adult kidney transplant recipients with invasive CMV disease. Both patients were diagnosed with CMV disease after they underwent allograft biopsy, which demonstrated the rare finding of CMV inclusions in the kidney allograft.

Background We investigated circulating levels of individual soluble urokinase plasminogen activation receptor (suPAR) forms to determine if specific circulating fragments of suPAR (II-III) and (I) can better serve as clinical biomarkers for focal segmental glomerulosclerosis (FSGS) and the risk of recurrence after transplantation. Materials and methods Serum levels of intact suPAR and its cleaved forms were measured with two assays, ELISA and TR-FIA. Results suPAR levels in healthy controls were significantly lower than those who had glomerular diseases but were not significantly different between FSGS patients and glomerular controls. Intact suPAR (I-II-III) levels were noted to be elevated in glomerular diseases including FSGS. uPAR fragment (I) levels measured with the TR-FIA 4 assay were significantly higher in FSGS (695.4 + 91.29 pMol/L) than glomerular controls (239.1 + 40.45 pMol/L, P = 0.001). However, suPAR(I) levels were not significantly different between recurrent FSGS and nonrecurrent FSGS patients. Conclusion Our analysis of suPAR using the ELISA assay used in all previous studies does not appear to be a useful marker for FSGS nor serve as a predictor for its recurrence after transplantation. The TR-FIA assay results suggest that uPAR(I) is a potential biomarker for FSGS but not of its recurrence.

We present an 11 yr old girl who received 3 kidney transplants (KTx). She received 1st-KTx from a living donor at age 4 due to the end-stage renal disease. She had no HLA antibodies (Ab) at pre-1st-KTx, and thus pre-tx crossmatch (XM) and donor-specific HLA antibodies (DSA) were −ve. Six weeks later, the allograft was removed due to torsion (twisting of blood vessels) and thrombosis (formation of a blood clot). The C4d staining of Tx-biopsy was −ve indicating no antibody-mediated rejection (ABMR). She was relisted for the 2nd-KTx. Two-mo post tx-nephrectomy sample revealed Abs to all 10 mismatched (MM) donor’s HLA types (and associated CREG) resulting in 97% CPRA. After a 3 yr wait, she received 2nd-KTx from a deceased donor (DD) with −ve XM and DQ8 DSA (MFI = 1961). Shortly, she developed complications by BK viremia/nephropathy and immunosuppression was reduced, which potentially increased alloimmune activation. At 2-mo post-2nd-KTx, she developed de novo DSAs directed against 4 mismatched HLAs of 2nd-KTx (1600–14600 MFI). She was treated with multiple rounds of eculizumab, plasmapheresis and IVIG until Dec. 2015, when she presented with an acute increase in serum creatinine to 8.7 mg/dL. KTx biopsy showed acute ABMR. She was relisted for 3rd-KTx on Feb. 2016 with a cPRA 100%. After 2 yr wait, she received 3rd-KTx on Feb. 2018 from a DD with −ve XM and no DSA. The 3rd donor was mismatched by 8 HLA antigens - 1 of them was a repeat-MM with 1st donor and another was repeat-MM with both 1st and 2nd donors. However, Abs to 5 mismatched HLAs of the 3rd-KTx (B8, B37, Cw6, DP2, DP4) found in the historical sera (MFIs 1000–16,000) were completely −ve in multiple sera tested during 2 mo post-3rd-KTx (Fig.). No rejection was noted. Lessons learned from this case were: A 4-yr old human immune system can recognize and respond to alloantigens, and can trigger HLA-Abs production efficiently. However, acquired memory response, an integral component of adaptive immunity is not fully developed until 11 yr of age. These findings have vital implications in pediatric KTxs. Download : Download high-res image (508KB) Download : Download full-size image

Aim We developed a reliable virtual crossmatch (VXM) method for use as pre-transplant XM for deceased donor (DD) kidney transplantation (Ktx). Here we report the outcomes of 248 Ktx performed based on VXM. Methods Our VXM method includes 3 integral processes: accurate identification of HLA antibodies (Ab) using right tools and principles, assessment of correlation between the strength of donor specific Ab (DSA) and T and B cell bindings by flow XM (FXM), and listing of clinically relevant unacceptable antigens that will not impact DD offers or graft survival. From the start of the new KAS through Dec. 2016, 434 DD-Ktx were performed at UCSF, of which 375 (86%) were performed based on VXM (350 were VXM−ve with DSA+/− and 25 were VXM+ve with DP/DQα DSA+). 59/434 (14%) of the Ktxs were performed based on pre-tx FXM (54 were FXM−ve with DSA+/− and 5 were FXM+ve with DP-DSA+). Six month protocol biopsy (Bx) and cause Bx were evaluated for C4d rejection. Results All 350 pre-tx VXM−ve assessments were negative by retrospective FXM. There were no hyper acute rejections in these 350 Ktx. Biopsies of 273 negative VXM-based Ktx revealed no significant difference in the rate of antibody-mediated rejection (ABMR) or in acute cellular rejection (ACR) between 3 distinct CPRA groups (Table). Females, re-tx, well-matched tx, and de nova DSA producers were more frequent in both high CPRA groups compared to 0–79% CPRA group. Pre-tx DSA was more common in 99–100% CPRA group compared to other groups. Conclusions Our VXM protocol is reliable, has excellent graft survival, and works even for those with 100% CPRA. Accurate VXM method improves organ allocation for broadly sensitized patients, increases the efficiency of regional/national sharing, and avoids reallocation into unintended recipients. Download : Download high-res image (137KB) Download : Download full-size image

Human immunodeficiency virus (HIV)-associated nephropathy (HIVAN) is one of the most important causes of progressive kidney failure in HIV-1-seropositive patients. Since the 1980s, much has been published regarding the epidemiology, pathogenesis, and treatment of HIVAN. Our knowledge of the clinical features, pathologic manifestations, course, and potential outcome of HIVAN has increased considerably. The use of highly active antiretroviral therapy has shown significant improvement in the outcome of human immunodeficiency virus infection and is found to be effective in preventing end-stage renal disease. The purpose of this review is to summarize the data about the clinical manifestations, pathogenesis and pathophysiologic mechanisms of HIVAN with particular attention on treatment including pharmaceutical and renal replacement options.

Mesothelin, a cell surface glycoprotein present on normal mesothelial cells, has been reported to be expressed in pancreatic adenocarcinomas. We conducted this study to fully characterize mesothelin expression in surgically resected, formalin-fixed, paraffin-embedded tissue specimens of 18 pancreatic adenocarcinomas, 9 adenocarcinomas of the ampulla of Vater, 12 adenocarcinomas of the common bile duct, and 17 cases of chronic pancreatitis. Mesothelin immunostaining was performed using the antimesothelin monoclonal antibody 5B2. All 18 cases (100%) of pancreatic adenocarcinomas showed mesothelin expression, as did 8 (89%) of 9 cases of ampullar adenocarcinoma and all 12 cases (100%) of common bile duct adenocarcinoma. In all cases of pancreaticobiliary adenocarcinoma, the adjacent normal pancreas did not stain for mesothelin. Of 17 specimens of chronic pancreatitis, 16 were negative for mesothelin expression, and 1 case showed weak mesothelin staining of fewer than 5% of normal pancreatic ducts. Our results demonstrated mesothelin expression in the majority of pancreaticobiliary adenocarcinomas and no expression in normal pancreatic tissues and in chronic pancreatitis.

Tamm-Horsfall protein knockout mice are more prone to urinary tract infection. Background Human colon contains many bacteria that commonly colonize the perineum and frequently enter the urinary tract. Uropathogenic Escherichia coli are the most common cause of urinary tract infection. Type 1 fimbriated E. coli have been associated with cystitis, and P fimbriated E. coli with pyelonephritis. Factors involved in clearing bacteria from the urinary tract are poorly understood. Tamm-Horsfall protein (THP), the most abundant protein in mammalian urine, has been postulated to play a role in defense against urinary tract infection but definitive proof for this idea has been lacking. Methods In this study, we generated THP gene knockout mice by the technique of homologous recombination, and examined if the THP-deficient (THP -/- ) mice were more prone to urinary tract infection. Various strains of E. coli expressing type 1 or P fimbriae were introduced transurethrally into the bladders of the THP -/- and genetically similar wild-type (THP +/+ ) mice. Urine, bladder, and kidney tissues were obtained from the mice and cultured for bacterial growth. Results THP -/- mice inoculated with type 1 fimbriated E. coli had a longer duration of bacteriuria, and more intense colonization of the urinary bladder in comparison with THP +/+ mice. When inoculated with a P fimbriated strain of E. coli, the THP -/- mice showed no difference in kidney bacterial load when compared with the THP +/+ mice. Conclusion These findings support the idea that THP serves as a soluble receptor for type 1 fimbriated E. coli and helps eliminate bacteria from the urinary tract.

Coronary atherosclerosis with occlusive thrombosis is the major cause of acute myocardial infarction. Although plaque rupture is usually hypothesized to be the predisposing event in coronary thrombosis, the possibility cannot be excluded that local changes in the anticoagulant properties of the endothelium overlying the plaque contribute to this process. It is evident that thrombomodulin and the endothelial cell protein C receptor are critical players in the control of the thrombogenic process. This study examined whether thrombomodulin and the endothelial cell protein C receptor are down-regulated on endothelial cells overlying the atherosclerotic plaque in coronary arteries and thus could potentially favor local thrombus formation. Sections of archival left and right coronary arteries (n = 18 each) with severe atherosclerosis from the native heart of six patients who underwent heart transplantation were immunostained for CD31, CD34, endothelial cell protein C receptor, and thrombomodulin using a streptavidin-biotin-peroxidase method. Controls included left and right coronary arteries from autopsy cases with no atherosclerosis (n = 6), and also from cases with mild atherosclerosis (n = 5). The apparent density of all of these proteins was much higher in control than in atherosclerotic arteries. Our findings support the hypothesis that both endothelial cell protein C receptor and thrombomodulin are down-regulated in coronary arteries with atherosclerosis. These changes would be expected to result in reduced inhibition of thrombogenic and anti-inflammatory activity on the endothelium overlying atherosclerotic regions and thus could contribute to coronary thrombosis.

Infection with certain strains of Escherichia coli and endotoxemia results in renal glomerular thrombotic microangiopathy (TMA) characterized by endothelial swelling and prominent glomerular microthrombus formation. Nitric oxide (NO) is an endogenous biologic modulator with diverse physiologic functions including vasodilation and inhibition of platelet adhesion and aggregation. NO is synthesized from conversion of L-arginine to L-citrulline by a family of NO synthases (NOS), which include constitutive and inducible isoforms. Indirect evidence supports the hypothesis that TMA is associated with depressed intrarenal NO production. However, the effect of TMA on renal tissue NOS expression has not been fully elucidated. We studied rats with TMA induced by iv bolus injection of high dose (20 mg/kg) E. coli endotoxin. Subgroups of six animals each were sacrificed before or at 30, 90, 180, 360, and 720 minutes after the administration of endotoxin. Renal histology and tissue expression of endothelial and inducible nitric oxide synthases (eNOS and iNOS) were examined. Additionally, we examined the effect of endotoxin on glomerular NO production, and eNOS and iNOS protein expression in vitro. Glomerular capillary thrombosis developed by 180 minutes after endotoxin administration in approximately half of the animals. The glomeruli without thrombotic lesions apparent by light microscopy disclosed early signs of TMA characterized by endothelial swelling, platelet accumulation/adhesion, and patchy fibrinogen deposition. These morphologic changes were associated with a marked reduction of renal tissue eNOS expression beyond 180 minutes after the endotoxin administration. The fall in eNOS expression was coupled with a significant rise in iNOS protein abundance, which was expressed largely by glomerular circulating neutrophils and endothelial cells, peritubular vascular endothelium, and collecting ducts of cortex and medulla. In vitro incubation of isolated glomeruli with endotoxin also resulted in a marked reduction in eNOS expression and a significant rise in iNOS content. Administration of E. coli endotoxin leads to a sustained fall in renal eNOS expression both in vivo and in vitro. The associated decline in intrarenal endothelial NO production/availability may result in renal vasoconstriction and a hypercoagulative state, which may contribute to the pathogenesis of endotoxin-induced TMA.

Fasting induces pancreatic secretory lipase, possibly through an increased utilization of fatty acids and/or ketone bodies by the acinar cells. To test this hypothesis, the effects of l -aminocarnitine (ACA), an inhibitor of mitochondrial β-oxidation and ketone body formation, on the pancreatic enzyme composition were studied in rats. The characteristics and reversibility of the hepatic steatosis produced by ACA in fasted animals were also investigated. In fasted rats, ACA decreased the plasma levels of β-hydroxybutyrate, glucose and insulin, but increased that of glucagon. Fasting for 3 days increased the pancreatic lipase content by 80%. Administration of ACA (3, 10 or 30 mg kg−1daily) for 3 days to fasted rats led to dose-related decreases in pancreatic lipase content, the fasting-induced increase was prevented even by the lowest dose. Nevertheless, ACA in the fasted rats likewise decreased the pancreatic contents of protein, amylase and trypsinogen to varying degrees, suggesting a general defect of protein synthesis. The 3-day treatment with ACA during fasting led to dose-related, marked increases in hepatic weight and triglyceride content. Light and electron microscopy revealed lipid vesicles of varying sizes in the hepatocytes; the fat deposition was predominant in the periportal zones of the hepatic lobules. By means of electron microscopy, lipid vacuoles were observed in the centroacinar cells, but not in the acinar cells of the pancreas. In rats treated with 30 mg kg−1of ACA daily for 3 days while they were fasted, cessation of ACA treatment and refeeding with normal chow led to normalization of the pancreatic enzyme contents within 6 days, and gradual and complete disappearance of the hepatic steatosis within 24 days. Microscopy also demonstrated complete recovery in both the liver and the pancreas. The results indicate that pancreatic secretory lipase induction during the adaptive phase of starvation is dependent on an unhindered mitochondrial β-oxidation of fatty acids and ketogenesis. The dose-related degree of hepatic triglyceride accumulation which can be produced readily by administration of ACA during short-term starvation in the rat may serve as a new, convenient experimental model for studies of fatty liver. 2000 Academic Press@p$hr

67-year-old woman presented with low-grade proteinuria (1040 mg/24 h) and hypertension (170/90 mm Hg). Urinalysis showed dark yellow, nonturbid urine that was negative for leukocyte esterase. The urine had a specific gravity of 1.030, pH 6.0, no glucose, and trace ketones. Laboratory findings also revealed negativity for bilirubin, blood, and nitrite in the urine. White blood cell count was 4 to 6/mm 3 . Other aspects of the physical examination were unremarkable. The patient’s medical history was significant for low-grade proteinuria (approximately 1000 mg/24 h) of 12 years and hypertension of 4 years. She had no previous history of microscopic or macroscopic hematuria, renal stones, epistaxis or hemoptysis, flank pain, or history suggestive of a connective tissue disease. She had no significant family history. A renal biopsy was performed to identify the etiology of her long-standing proteinuria. The specimen submitted for light microscopic study consisted of a single core of renal cortical tissue with up to 8 glomeruli per section, 3 of which were globally collapsed and sclerotic. The other glomeruli had patent glomerular capillary lumina; no glomerular hypercellularity was noted. A single glomerulus revealed a segmentally sclerotic segment. The visceral epithelial cells were distended by fine intracytoplasmic vacuoles (Figure 1, arrows). The interstitium exhibited slight focal widening

Microvascular endothelial cell injury plays a central role in the pathogenesis of a set of diseases known as endotheliopathies. Typically, such diseases demonstrate prominent renal manifestations since the kidneys are richly vascularized. Morphologically, endotheliopathies classically demonstrate features of thrombotic microangiopathy on renal biopsy and include diseases such as hemolytic uremic syndrome (HUS), thrombotic thrombocytopenic purpura (TTP), and preeclampsia. Recent advances have elucidated several mechanisms by which endothelial injury may occur leading to the development of endotheliopathies. More specifically, direct cytotoxic endothelial injury is caused by exposure to Shiga or Shiga-like toxins following gastroenteritis in classic HUS, while atypical HUS has been traced to endothelial perturbation due to overactivation of the alternative complement pathway. In TTP, abrogated ADAMTS13 activity leads to the accumulation of uncleaved large multimers of von Willebrand factor, which in turn causes inappropriate platelet aggregation and endothelial damage. In preeclampsia, soluble circulating factors likely derived from the placenta act as antagonists to the glomerular endothelial cell microenvironment, inciting endothelial cell injury. Understanding the molecular mechanisms by which these diseases develop and progress will greatly aid in the design and implementation of effective treatments specific to each endotheliopathy.

Exudative pleural effusions are characterized by a high protein content and frequently progress to loculation and fibrosis. To test the hypothesis that tissue factor (TF) plays an integral role in this process, we investigated the expression of TF by human mesothelial cells (HMC) both in vivo and in vitro, and measured the effect of serum on HMC expression of TF in vitro. In vivo TF expression was not detected in HMC of normal pleura, but was detected in HMC of pleura overlying inflamed lung. In vitro, quiescent HMC demonstrated negligible levels of TF expression; however, upon serum stimulation there was a marked induction in both TF protein level and activity, peaking at 8-9 h. In contrast, treating quiescent HMC with plasma resulted in a further small, but significant, decrease in TF expression. This serum-induced rise in TF was also reflected in TF mRNA levels and did not require de novo protein synthesis. These results suggest that induction of HMC TF expression may be important in triggering both the intrapleural activation of prothrombin and the deposition of fibrin characteristic of inflammatory effusions.

A spectrum of kidney diseases besides classic human immunodeficiency virus (HIV)-associated nephropathy (HIVAN) exists in HIV-infected patients. Immune complex–mediated glomerulonephritis has emerged as a significant contributor to the burden of kidney disease in this population, particularly in patients of non-African descent. Lupus-like nephritis, a form of immune complex glomerulonephritis with histologic features identical to lupus nephritis in the absence of clinical or serologic markers of lupus, is well recognized as a cause of end-stage renal disease in HIV-infected patients. None of the HIV-associated kidney lesions, whether classic HIVAN or non-HIVAN, has been reported to recur in kidney transplants. We report here for the first time clinical and histologic recurrence of HIV-associated lupus-like nephritis after successful kidney transplantation, causing proteinuria, hematuria, and impaired kidney transplant function.

To determine the nephron segment distribution of tubular epithelial damage and regeneration and the proliferative activity of various nephron segments in human acute tubular necrosis (ATN) with an antibody to proliferating cell nuclear antigen (PCNA) and to compare the findings in native kidneys with ATN with those in transplant kidneys with ATN, archival tissues from 12 native and 21 transplant kidney biopsy specimens and nine transplant nephrectomy specimens were collected that all showed obvious morphological signs of ATN. Nineteen patients with transplant kidneys with ATN were immunosuppressed with cyclosporine and 11 were immunosuppressed with prednisone and azathioprine. There was a predominance of "regenerating" tubules (tubules with thin epithelium) in the distal nephron in native kidneys with ATN; in the transplant kidneys this was less conspicuous. The number of Tamm-Horsfall protein (THP)-positive tubules was decreased in all kidneys with ATN compared with normal human kidneys. In contrast, the number of THP-positive casts was much higher in all kidneys with ATN than in the normal kidneys. In transplant kidneys with ATN the number of THP-positive casts was substantially lower than in native kidneys with ATN. The macula densa appears to maintain its morphological integrity in kidneys with ATN. Both regenerating and normal appearing tubules expressed vimentin and HLA-DR. The proliferation index (PI; ie, percentage of PCNA-positive nuclei) of the renal tubular epithelium in normal control kidneys varied between 0.22 and 0.33, depending on the tubule segment. The highest PI was noted in the transplant kidneys with ATN not treated with cyclosporine (8.0), followed by the native kidneys with ATN (4.4) and the transplant kidneys with ATN treated with cyclosporine (4.3). We did not find any significant difference in the PI between the regenerating (5.0) and normal appearing (5.6) tubules. Proximal tubules (8.7) showed significantly higher PI values than distal tubules (3.5) in transplant kidneys with ATN. Our results show substantial differences between native kidneys and transplant kidneys with ATN. Tubular epithelial cell proliferation in human ATN is prominent and appears to correlate with the severity of ATN. Light microscopically normal appearing tubules and regenerating tubules participate equally in the regeneration of injured tubules. Cyclosporine may have an inhibitory effect on cell regeneration (proliferation) in human transplant kidneys with ATN.

Dramatic hemodynamic alterations occur during a normal, healthy pregnancy with the kidneys playing a major role to ensure that these adaptive changes occur properly. Therefore, it is not surprising that a significant number of women may develop new onset renal dysfunction or exacerbation of preexisting renal disease during pregnancy. Perhaps the most commonly encountered gestational disorder is hypertension, which can lead to significant complications for both the mother and the fetus when left untreated. A variety of factors may cause or contribute to the development or worsening of hypertension during pregnancy; nevertheless, clinically, hypertensive disorders of pregnancy can be divided into four major categories as recommended by the National High Blood Pressure Education Program Working Group on High Blood Pressure in Pregnancy: preeclampsia, chronic/preexisting hypertension, preeclampsia superimposed upon chronic hypertension, and gestational hypertension [1]. Of particular importance in defining these categories is the time of onset of hypertension during pregnancy, whether the women had preexisting hypertension prior to pregnancy, and whether proteinuria is present. Hypertension prior to pregnancy or occurring before 20 weeks of gestation indicates chronic/preexisting hypertension while hypertension occurring after 20 weeks of gestation but without proteinuria defines gestational hypertension. Preeclamspia is gestational hypertension with the additional feature of proteinuria. Of these hypertensive disorders of pregnancy, preeclampsia is the most common and can cause devastating systemic consequences including substantial renal injury. In this chapter, we discuss the pathologic manifestations and molecular pathologenesis of preeclampsia with a special emphasis on the renal effects of this disease.

Shiga toxin–producing Escherichia coli (STEC) is the most common cause of diarrhea-positive hemolytic uremic syndrome (HUS). Producing considerable morbidity and mortality, diarrhea-positive HUS is characterized by hemorrhagic colitis, microangiopathic hemolytic anemia (MHA), thrombocytopenia, and acute renal failure. Although the gastrointestinal tract and the kidney are the organs most commonly affected, central nervous system, skeletal, pancreatic, and myocardial involvement also can occur. Despite the significant progress made during the past few years in understanding the pathogenesis of STEC-associated HUS, the precise sequence of events by which infection causes disease is still unclear. Efforts to address this question in vivo have been hampered greatly by the lack of animal models that fully recapitulate the entire spectrum of HUS as seen in humans. Though STEC strains cause gastrointestinal, neurologic, or systemic symptoms in gnotobiotic piglets, rabbits, and mice, no such models have shown the hallmark histopathologic finding of renal thrombotic microangiopathy (TMA) following oral ingestion of bacteria; a baboon model has shown such changes but only with intravenous infusion of Shiga toxin 1.1 More recently, ferrets infected orally with E coli O157:H7 were shown to develop damage to glomeruli mimicking that seen in HUS by light microscopy.2 In this issue of the Journal, Gunzer and colleagues3 present a gnotobiotic piglet model of renal TMA using oral infection with O157:H7 or O26:H11 wild-type isolates of enterohemorrhagic E coli (EHEC). The authors demonstrate that the morphologic features of renal TMA in the piglets closely resemble those seen in human HUS. In addition, colitis and myelin degeneration, both of which are typical of human disease, were detected. However, the thrombocytopenia, MHA, and renal failure seen in human disease were not produced. HUS has been modeled before with gnotobiotic piglets. Various reports showed neurologic signs and vascular damage in the brains of gnotobiotic piglets infected orally with E coli O157:H7.4,5 However, in the study that looked for renal disease, there was no evidence of renal TMA.5 So, why were Gunzer and coworkers3 able to reproduce the typical renal changes of TMA experimentally while other researchers could not? These seemingly contradictory results may be explained by differences in virulence of the STEC strains used in the respective studies. Gunzer and colleagues3 used E coli isolated from HUS cases in Walla Walla, WA (serotype O157:H7), and Hannover, Germany (serotype O26:H11). Although previous studies also used O157:H7 serotypes, bacteria of the same serotype may have significant genetic differences that could cause variations in virulence. Perhaps the most important factor in virulence is the quantity of Shiga toxin 2 produced by the bacteria. However, qualitative differences in virulence also may be contributory. As the recently completed genomic sequence of EHEC O157:H7 suggests, there may be several additional uncharacterized virulence factors.6 Considering our incomplete understanding of HUS, the opportunity to use genetically modified strains of E coli makes the availability of a suitable animal model all the more valuable. The probable initial step in pathogenesis of STEC-associated HUS, adhesion, is a complex interaction between the bacteria and the intestinal wall. In vitro studies suggest that E coli O157:H7 initially binds small bowel epithelium associated with Peyer patches, followed by large intestine colonization.7

The renal microvasculature is composed of the glomerular and peritubular capillary beds which supply the cellular constituents of the kidney with oxygen and nutrients as well as maintain renal function by providing an adequate glomerular filtration rate. As a result, endothelial dysfunction within the kidney can lead to devastating consequences. Recently, a plethora of information regarding the molecular players involved in kidney microvasculature development and disease has emerged. Many of these studies focus on intricate signaling pathways within the local microenvironment of endothelial cells. Here, we highlight some of these studies and relate them to the molecular pathogenesis of glomerular and peritubular endothelialcells in both native and transplant renal diseases.

Clinical data and necropsy findings are presented on two patients: a 30 year old woman with proteinuria, decline in renal function, pancytopenia, arthritis; and pleural effusion, and a 76 year old man with liver cirrhosis, massive proteinuria, deterioration in renal function, and leukopenia. The cause of death was lung hemorrhage and bronchopneumonia, respectively. An immunofluorescence (IF) and electron microscopic (EM) postmortem evaluation of the kidneys revealed glomerular and tubulo-interstitial immune complex deposition in both patients. IF demonstrated the simultaneous presence of IgG and Clq. Lightmicroscopically (LM), diffuse proliferative glomerulonephritis with wire loops and a mixture of membranous, mesangio- and membrano-proliferative glomerulonephritis were seen, respectively. The clinical and morphological data collectively indicated that both patients had lupus nephritis. The combination of postmortem LM, IF and EM seems to be essential to make a definitive anatomic diagnosis incli...

Proteus mirabilis is a common cause of urinary tract infection. We determined the role of Tamm-Horsfall protein as a host defense factor against the cystitis and pyelonephritis caused by P. mirabilis.We generated Tamm-Horsfall protein gene knockout mice using homologous recombination. We introduced P. mirabilis transurethrally into the bladder of Tamm-Horsfall protein deficient (THP(-/-)) and genetically similar WT (THP(+/+)) mice. We cultured urine to quantitate the degree of bacteriuria. We examined bladders and kidneys grossly and histomorphometrically to determine the intensity of inflammation.THP(-/-) mice had more severe bacteriuria and cystitis than THP(+/+) mice. THP(-/-) mice had more pyelonephritic abscesses than THP(+/+) mice. The severity of histological pyelonephritis on semiquantitative histomorphometric analysis appeared to be greater in THP(-/-) mice. The difference between the 2 groups approached but did not attain statistical significance (p = 0.053).Tamm-Horsfall protein acts as a host defense factor against P. mirabilis induced urinary tract infection.

The integrity of rat pancreatic acinar cells under the influence of human phospholipase A2 (PLA2) was studied. Isolated pancreatic acini showed no increased discharge of aspartylaminotransferase (ASAT) when incubated either in solutions containing human pancreatic PLA2 or the bile salt sodium deoxycholate (DEC), the latter in concentrations that augment PLA2 activity but have no destructive detergent effect. When human pancreatic PLA2 was injected into the rat pancreatic duct, uneven distribution was observed at 15 min and 3 h in immunohistochemical sections. Edema and a mild inflammatory reaction were the main changes in the pancreas. The necrotic areas seen by light and electron microscopy were quite small and located mostly at the periphery of lobules corresponding the spread of the injected material. Necrosis was of the coagulation type and showed equal extent after the injection of PLA2 with or without DEC. Internalized human pancreatic PLA2 was present already 15 min after the injection in the cytoplasm of some intact acinar cells, indicating a functioning protective mechanism. It was concluded that pancreatic acinar cells are quite resistant to PLA2-catalyzed hydrolysis of membrane phospholipids in vitro, but additional trauma, e.g., pressure caused by intraductal injection, and tissue related factors, such as the mediators of the inflammatory reaction, make acinar cells susceptible to the effect of PLA2.

The effects of vitamin E on tissue oxidation, kidney function and morphology were studied in rats with nephrotoxic nephritis (NTN). Thirty-six nephritic animals received no treatment (group 1), while 36 were treated with vitamin E (group 2). Twenty-four hours after the administration of anti-glomerular basement membrane antibody, sulfhydryl-containing renal protein was significantly lower in group 1 than in group 2 (0.70 +/- 0.16 and 1.08 +/- 0.06 mmol/100 g kidney tissue, respectively), suggesting a free oxygen radical scavenging effect of vitamin E in group 2. The difference was similar on day 14. The creatinine clearance was significantly lower in group 1 than in group 2 on day 1 (40 +/- 30 and 204 +/- 60 microliter/min per 100 g body weight, respectively). The protein excretion was initially high in both groups, but a significant decrease was detected in group 2 relative to group 1 on day 14 (25 +/- 18 and 92 +/- 38 mg/24 h, respectively). The morphological changes were less severe in group 2. Vitamin E treatment did not alter any of the above values significantly in healthy animals. The release of oxygen free radicals in NTN might play an important role in the pathogenesis, which can be influenced by free radical scavengers through changes in kidney function and morphology.

Background. Posttransplantation thrombotic microangiopathy (PTMA) is a complication of allogeneic hematopoietic stem cell transplantation (HSCT). However, limited autopsy data are available, and it remains unclear whether PTMA is a discrete clinical and pathologic entity. The aims of this autopsy study were to determine the correlation between clinical and pathologic diagnosis of PTMA, to define the precise morphologic spectrum of PTMA, and to seek for potential etiologic factors. Methods. The study included 20 consecutive patients with HSCT autopsied at the University of Oklahoma, between 1994 and 2005. Applying strict clinical-laboratory criteria, 6 patients were diagnosed clinically with PTMA and treated with plasma exchange. Clinical variables, including underlying disease, conditioning regimen, stem cell donor status, duration and serum level of cyclosporine, infections, and acute graft versus host disease were compared statistically in patients with histologic signs of PTMA (n= 8) with those without PTMA (n= 12). Results. PTMA was verified histologically in all 6 patients with a clinical diagnosis ofPTMA but only 2 of the 14 patients who were not clinically diagnosed had histologic evidence of PTMA (P

With the advent of calcineurin inhibitors, the success of kidney and other solid-organ transplants has improved significantly from the standpoint of reducing the incidence of acute rejection. Over the past 2 decades, both short-term allograft survival and acute rejection rates have dramatically improved with improved diagnostic and therapeutic techniques such as standardized pathology scoring; potent antirejection drugs such as anti–thymocyte globulin, interleukin-2 receptor antibodies, cyclosporine, tacrolimus, sirolimus, and mycophenolate mofetil; and improved infection control such as valganciclovir and antifungal therapy. However, long-term graft loss has remained at nearly constant levels over the same period of time, with the average half-life of a deceased-donor kidney transplant in the United States remaining approximately 1 decade. In addition to death with a functioning allograft and calcineurin toxicity, a chronic fibrotic process—known at various times as chronic rejection, chronic allograft dysfunction, and chronic allograft nephropathy (CAN)—account for the leading causes of transplant failure.

Impairment of the protein C anticoagulation pathway is critical to the thrombosis associated with sepsis and to the development of purpura fulminans in meningococcemia. We studied the expression of thrombomodulin and the endothelial protein C receptor in the dermal microvasculature of children with severe meningococcemia and purpuric or petechial lesions.We assessed the integrity of the endothelium and the expression of thrombomodulin and the endothelial protein C receptor in biopsy specimens of purpuric lesions from 21 children with meningococcal sepsis (median age, 41 months), as compared with control skin-biopsy specimens.The expression of endothelial thrombomodulin and of the endothelial protein C receptor was lower in the patients with meningococcal sepsis than in the controls, both in vessels with thrombosis and in vessels without thrombosis. On electron microscopical examination, the endothelial cells were generally intact in both thrombosed and nonthrombosed vessels. Plasma thrombomodulin levels in the children with meningococcal sepsis (median, 6.4 ng per liter) were higher than those in the controls (median, 3.6 ng per liter; P=0.002). Plasma levels, protein C antigen, protein S antigen, and antithrombin antigen were lower than those in the controls. In two patients treated with unactivated protein C concentrate, activated protein C was undetectable at the time of admission, and plasma levels remained low.In severe meningococcal sepsis, protein C activation is impaired, a finding consistent with down-regulation of the endothelial thrombomodulin-endothelial protein C receptor pathway.

Chronic iron (Fe) overload is associated with a marked increase in renal tissue iron content and injury. It is estimated that 10% of the American population carry the gene for hemochromatosis and 1% actually suffer from iron overload. The mechanism of iron overload-associated renal damage has not been fully elucidated. Iron can accelerate lipid peroxidation leading to organelle membrane dysfunction and subsequent cell injury/death. Iron-catalyzed generation of reactive oxygen species (ROS) is responsible for initiating the peroxidatic reaction. We investigated the possible association of oxidative stress and its impact on nitric oxide (NO) metabolism in iron-overload-associated renal injury. Rats were randomized into Fe-loaded (given 0.5 g elemental iron/kg body weight as iron dextran; i.v.), Fe-depleted (given an iron-free diet for 20 weeks), and control groups. Renal histology, tissue expression of endothelial and inducible nitric oxide synthases (eNOS and iNOS), renal tissue expression of nitrotyrosine, plasma, and renal tissue lipid peroxidation product, malondialdehyde (MDA), and plasma and urinary NO metabolites (NOx) were examined. Iron overload was associated with mild proteinuria, tissue iron deposition together with significant glomerulosclerosis, tubular atrophy, and interstitial fibrosis. Rare focal glomerulosclerosis and tubulointerstitial changes were noted in normal controls. No renal lesions were observed in Fe-depleted rats. Iron deposits were seen in glomeruli, proximal tubules, and interstitium. The iron staining in the distal tubules was negligible. Both plasma and renal tissue MDA and renal tissue nitrotyrosine were increased significantly in Fe-loaded rats compared with control rats. In contrast, Fe-depleted animals showed a marked reduction in plasma and renal tissue MDA and nitrotyrosine together with significant elevation of urinary NOx excretion. In addition, iron-overload was associated with up-regulation of renal eNOS and iNOS expressions when compared with the control and Fe-depleted rats that showed comparable values. In conclusion, chronic iron overload resulted in iron deposition in the glomeruli and proximal tubules with various renal lesions and evidence of increased ROS activity, enhanced ROS-mediated inactivation, and sequestration of NO and compensatory up-regulation of renal eNOS and iNOS expressions. However, iron depletion was associated with reduced MDA and tissue nitrotyrosine abundance, increased urinary NOx excretion, normal nitric oxide synthase (NOS) expression, and absence of renal injury. These findings point to the possible role of ROS in chronic iron overload-induced renal injury.

Increased proliferative activity of the renal tubular epithelium is thought to be a prerequisite for renal cyst formation by many investigators. However, in humans, the exact in vivo proliferation rate of epithelial cells lining these cysts is not known. In this study, which used immunohistochemical methods with an antibody to proliferating cell nuclear antigen (PCNA), the proliferation index (PI) (percentage of PCNA positive cell nuclei among epithelial cells lining the renal cysts) was determined in 10 cases of autosomal dominant polycystic kidney disease (ADPKD), 8 cases of autosomal recessive polycystic kidney disease (ARPKD), and 8 cases of acquired cystic kidney disease (ACKD). Cysts with proximal and distal nephron phenotype and cysts with markedly thickened basement membranes, as well as cysts lined by atrophic (flattened), "regular" (cuboidal or cylindrical), and hyperplastic epithelium, were evaluated separately. The overall PI of cyst epithelium (excluding hyperplastic cysts) was 2.58 in ADPKD, was 10.5 in ARPKD, and was 3.61 in ACKD. Overall, there were only minor differences in the PI between the various types of cysts. Cysts with hyperplastic epithelium in ACKD (unlike in ADPKD) showed a high PI (9.1). For comparison, the PI of two renal cell carcinomas occurring in two ACKD cases was also determined (13.70 and 8.67%). The PI of tubular epithelium in normal kidneys was only 0.22 to 0.33%, depending on the tubule segment. In contrast, in polycystic kidneys, those noncystic segments of the nephron from which the cysts are thought to originate (distal nephron (specifically collecting duct)) in ARPKD, primarily distal in ADPKD, proximal and distal in ACKD, had PI values similar to those of the cyst epithelium.(ABSTRACT TRUNCATED AT 400 WORDS)