An Unusual Case of Anti-Glomerular Basement Membrane Disease and Phospholipase A2 Receptor-Associated Membranous Nephropathy After Exposure to Hydrocarbons

We present a rare case of a patient with toluene exposure manifesting as anti-glomerular basement membrane (GBM) disease on a background of phospholipase A2 receptor (PLA2R)-associated membranous nephropathy. A 23-year-old man presented to the emergency department with hypertension, headache, hemoptysis, anemia, acute kidney injury, glomerular hematuria, and proteinuria. He endorsed repeated exposure to toluene-containing products while repairing dirt bikes. Serologies were positive for anti-GBM antibodies. Kidney biopsy showed crescentic glomerulonephritis with linear immunoglobulin G and granular PLA2R staining by immunofluorescence. He was initially treated with high-dose steroids, plasmapheresis, and hemodialysis for pulmonary-renal syndrome followed by oral cyclophosphamide and prednisone, which were discontinued after 3 months when follow-up biopsies confirmed little chance for renal recovery. He remained on dialysis 1 year later. This case exhibits a unique presentation of anti-GBM syndrome and underlying membranous nephropathy following repeated hydrocarbon exposure. Inhaled toxins promote recurrent localized inflammation, unmasking previously hidden epitopes. Early diagnosis and appropriate use of immunosuppressive and extracorporeal therapies are necessary to prevent morbidity and to improve survival in this rare condition.

Gene expression profiling in skin reveals strong similarities between subacute and chronic cutaneous lupus that are distinct from lupus nephritis

Subacute cutaneous lupus erythematosus (SCLE) and chronic cutaneous lupus erythematosus (CCLE) are represented in the majority of cutaneous lupus subtypes, each of which has variable implications for systemic manifestations such as lupus nephritis. On dermatologic exam, SCLE and CCLE are distinct. However, it is often difficult to diagnose the subtype from histology alone. Our study utilized whole-genome microarray expression analysis on human skin samples of SCLE, CCLE, and healthy controls, along with human samples of lupus nephritis and normal kidney tissue to compare cutaneous lupus subtypes to each other, as well as lupus nephritis. The data revealed that cutaneous lupus subtypes were distinct from healthy control skin, with gene expression predominantly characterized by upregulation of type 1 interferon and T-cell chemotactic genes. However, the cutaneous lupus subtypes were very similar to one another; comparative analyses revealed few statistically significant differences in gene expression. There were also distinct differences between the gene signatures of cutaneous lupus and lupus nephritis. Cutaneous lupus samples revealed gene signatures demonstrating a prominent inflammatory component that may suggest the skin as an early site of initiation of lupus pathogenesis, while lupus nephritis reflected recruitment and activation of M2 macrophages and a wound healing signature.

Transplantation of Renal Allograft After Removal of Renal Cell Carcinoma: Case Report and Review of the Literature

With the rising incidence of end-stage renal disease in the United States, patients needing renal transplants are waiting longer for increasingly scarce grafts. Formerly, the general practice was to avoid organs with tumors for transplant because of the risk of malignancy transmission to the recipient. However, with comprehensive donor selection and a small-sized primary tumor, the positive outcomes of transplant outweigh the risks of transmission after a partial nephrectomy. In our case, a 31-year-old woman, the daughter of the recipient, underwent a laparoscopic nephrectomy with an existing 8-mm tumor later confirmed as renal cell carcinoma. An ex vivo tumor enucleation was performed before the allograft was transplanted into the 69-year-old patient with endstage renal disease. At last follow-up, graft function has remained excellent with no evidence of local recurrence or metastasis in both the donor and recipient. Here, we describe our case and perform a literature review on the incidence and management of renal allografts with incidentally detected renal cell carcinoma during transplant.

The Syndrome of Tubulointerstitial Nephritis With Uveitis (TINU)

The syndrome of tubulointerstitial nephritis and uveitis (TINU) is a multisystemic autoimmune disorder that may occur in response to various environmental triggers, including drugs and microbial pathogens. Evidence exists of HLA antigen-related genetic predisposition to developing TINU. The resulting inflammation affects chiefly the ocular uvea and renal tubules, although other organs may be involved. TINU is uncommon; only about 200 cases are on record since its original description 40 years ago, although it is possible that new ones are no longer being reported. Although its incidence is highest in children and adolescents, all ages may be affected. Renal and ocular inflammation may be clinically severe and persistent, but the prognosis for the majority of patients with TINU is favorable. Owing to its low prevalence, no standard therapeutic protocols have been established, but most reported cases have been treated with corticosteroids or other immunomodulatory agents. TINU has many features in common with sarcoidosis, the main clinical entity from which it must be distinguished. This article begins with an illustrative case vignette, followed by an overview of the syndrome and current theories regarding its pathogenesis.

The ability of an attaching and effacing pathogen to trigger localized actin assembly contributes to virulence by promoting mucosal attachment

Enterohaemorrhagic Escherichia coli (EHEC) colonizes the intestine and causes bloody diarrhoea and kidney failure by producing Shiga toxin. Upon binding intestinal cells, EHEC triggers a change in host cell shape, generating actin 'pedestals' beneath bound bacteria. To investigate the importance of pedestal formation to disease, we infected genetically engineered mice incapable of supporting pedestal formation by an EHEC-like mouse pathogen, or wild type mice with a mutant of that pathogen incapable of generating pedestals. We found that pedestal formation promotes attachment of bacteria to the intestinal mucosa and vastly increases the severity of Shiga toxin-mediated disease.

A novel murine infection model for Shiga toxin-producing Escherichia coli

Enterohemorrhagic E. coli (EHEC) is an important subset of Shiga toxin-producing (Stx-producing) E. coli (STEC), pathogens that have been implicated in outbreaks of food-borne illness and can cause intestinal and systemic disease, including severe renal damage. Upon attachment to intestinal epithelium, EHEC generates "attaching and effacing" (AE) lesions characterized by intimate attachment and actin rearrangement upon host cell binding. Stx produced in the gut transverses the intestinal epithelium, causing vascular damage that leads to systemic disease. Models of EHEC infection in conventional mice do not manifest key features of disease, such as AE lesions, intestinal damage, and systemic illness. In order to develop an infection model that better reflects the pathogenesis of this subset of STEC, we constructed an Stx-producing strain of Citrobacter rodentium, a murine AE pathogen that otherwise lacks Stx. Mice infected with Stx-producing C. rodentium developed AE lesions on the intestinal epithelium and Stx-dependent intestinal inflammatory damage. Further, the mice experienced lethal infection characterized by histopathological and functional kidney damage. The development of a murine model that encompasses AE lesion formation and Stx-mediated tissue damage will provide a new platform upon which to identify EHEC alterations of host epithelium that contribute to systemic disease.

Allele- and tir-independent functions of intimin in diverse animal infection models

Upon binding to intestinal epithelial cells, enterohemorrhagic Escherichia coli (EHEC), enteropathogenic E. coli (EPEC), and Citrobacter rodentium trigger formation of actin pedestals beneath bound bacteria. Pedestal formation has been associated with enhanced colonization, and requires intimin, an adhesin that binds to the bacterial effector translocated intimin receptor (Tir), which is translocated to the host cell membrane and promotes bacterial adherence and pedestal formation. Intimin has been suggested to also promote cell adhesion by binding one or more host receptors, and allelic differences in intimin have been associated with differences in tissue and host specificity. We assessed the function of EHEC, EPEC, or C. rodentium intimin, or a set of intimin derivatives with varying Tir-binding abilities in animal models of infection. We found that EPEC and EHEC intimin were functionally indistinguishable during infection of gnotobiotic piglets by EHEC, and that EPEC, EHEC, and C. rodentium intimin were functionally indistinguishable during infection of C57BL/6 mice by C. rodentium. A derivative of EHEC intimin that bound Tir but did not promote robust pedestal formation on cultured cells was unable to promote C. rodentium colonization of conventional mice, indicating that the ability to trigger actin assembly, not simply to bind Tir, is required for intimin-mediated intestinal colonization. Interestingly, streptomycin pre-treatment of mice eliminated the requirement for Tir but not intimin during colonization, and intimin derivatives that were defective in Tir-binding still promoted colonization of these mice. These results indicate that EPEC, EHEC, and C. rodentium intimin are functionally interchangeable during infection of gnotobiotic piglets or conventional C57BL/6 mice, and that whereas the ability to trigger Tir-mediated pedestal formation is essential for colonization of conventional mice, intimin provides a Tir-independent activity during colonization of streptomycin pre-treated mice.

The programmed death-1 ligand 1:B7-1 pathway restrains diabetogenic effector T cells in vivo

Programmed death-1 ligand 1 (PD-L1) is a coinhibitory molecule that negatively regulates multiple tolerance checkpoints. In the NOD mouse model, PD-L1 regulates the development of diabetes. PD-L1 has two binding partners, programmed death-1 and B7-1, but the significance of the PD-L1:B7-1 interaction in regulating self-reactive T cell responses is not yet clear. To investigate this issue in NOD mice, we have compared the effects of two anti-PD-L1 Abs that have different blocking activities. Anti-PD-L1 mAb 10F.2H11 sterically and functionally blocks only PD-L1:B7-1 interactions, whereas anti-PD-L1 mAb 10F.9G2 blocks both PD-L1:B7-1 and PD-L1:programmed death-1 interactions. Both Abs had potent, yet distinct effects in accelerating diabetes in NOD mice: the single-blocker 10F.2H11 mAb was more effective at precipitating diabetes in older (13-wk-old) than in younger (6- to 7-wk-old) mice, whereas the dual-blocker 10F.9G2 mAb rapidly induced diabetes in NOD mice of both ages. Similarly, 10F.2H11 accelerated diabetes in recipients of T cells from diabetic, but not prediabetic mice, whereas 10F.9G2 was effective in both settings. Both anti-PD-L1 mAbs precipitated diabetes in adoptive transfer models of CD4(+) and CD8(+) T cell-driven diabetes. Taken together, these data demonstrate that the PD-L1:B7-1 pathway inhibits potentially pathogenic self-reactive effector CD4(+) and CD8(+) T cell responses in vivo, and suggest that the immunoinhibitory functions of this pathway may be particularly important during the later phases of diabetogenesis.

Auto-antibody production and glomerulonephritis in congenic Slamf1-/- and Slamf2-/- [B6.129] but not in Slamf1-/- and Slamf2-/- [BALB/c.129] mice

Several genes in an interval of human and mouse chromosome 1 are associated with a predisposition for systemic lupus erythematosus. Congenic mouse strains that contain a 129-derived genomic segment, which is embedded in the B6 genome, develop lupus because of epistatic interactions between the 129-derived and B6 genes, e.g. in B6.129chr1b mice. If a gene that is located on chromosome 1 is altered through homologous recombination in 129-derived embryonic stem cells (ES cells) and if the resultant knockout mouse is backcrossed with B6, interpretation of the phenotype of the mutant mouse may be affected by epistatic interactions between the 129 and B6 genomes. Here, we report that knockout mice of two adjacent chromosome 1 genes, Slamf1(-/-) and Slamf2(-/-), which were generated with the same 129-derived ES cell line, develop features of lupus, if backcrossed on to the B6 genetic background. By contrast, Slamf1(-/-) [BALB/c.129] and Slamf2(-/-) [BALB/c.129] do not develop disease. Surprisingly, Slamf1(-/-) [B6.129] mice develop both auto-antibodies and glomerulonephritis between 3 and 6 months of age, while disease fully develops in Slamf1(-/-) [B6.129] mice after 9-14 months. Functional analyses of CD4(+) T cells reveals that Slamf2(-/-) T cells are resistant to tolerance induction in vivo. We conclude that the Slamf2(-/-) mutation may have a unique influence on T-cell tolerance and lupus.

PD-L1 has distinct functions in hematopoietic and nonhematopoietic cells in regulating T cell responses during chronic infection in mice

The inhibitory receptor programmed death 1 (PD-1) is upregulated on antigen-specific CD8+ T cells during persistent viral infections. Interaction with PD-1 ligand 1 (PD-L1) contributes to functional exhaustion of responding T cells and may limit immunopathology during infection. PD-L1 is expressed on both hematopoietic and nonhematopoietic cells in tissues. However, the exact roles of PD-L1 on hematopoietic versus nonhematopoietic cells in modulating immune responses are unclear. Here we used bone marrow chimeric mice to examine the effects of PD-L1 deficiency in hematopoietic or nonhematopoietic cells during lymphocytic choriomeningitis virus clone 13 (LCMV CL-13) infection. We found that PD-L1 expression on hematopoietic cells inhibited CD8+ T cell numbers and function after LCMV CL-13 infection. In contrast, PD-L1 expression on nonhematopoietic cells limited viral clearance and immunopathology in infected tissues. Together, these data demonstrate that there are distinct roles for PD-L1 on hematopoietic and nonhematopoietic cells in regulating CD8+ T cell responses and viral clearance during chronic viral infection.

PD-L1 regulates the development, maintenance, and function of induced regulatory T cells

Both the programmed death (PD) 1–PD-ligand (PD-L) pathway and regulatory T (T reg) cells are instrumental to the maintenance of peripheral tolerance. We demonstrate that PD-L1 has a pivotal role in regulating induced T reg (iT reg) cell development and sustaining iT reg cell function. PD-L1^−/− antigen-presenting cells minimally convert naive CD4 T cells to iT reg cells, showing the essential role of PD-L1 for iT reg cell induction. PD-L1–coated beads induce iT reg cells in vitro, indicating that PD-L1 itself regulates iT reg cell development. Furthermore, PD-L1 enhances and sustains Foxp3 expression and the suppressive function of iT reg cells. The obligatory role for PD-L1 in controlling iT reg cell development and function in vivo is illustrated by a marked reduction in iT reg cell conversion and rapid onset of a fatal inflammatory phenotype in PD-L1^−/−PD-L2^−/− Rag^−/− recipients of naive CD4 T cells. PD-L1 iT reg cell development is mediated through the down-regulation of phospho-Akt, mTOR, S6, and ERK2 and concomitant with the up-regulation of PTEN, all key signaling molecules which are critical for iT reg cell development. Thus, PD-L1 can inhibit T cell responses by promoting both the induction and maintenance of iT reg cells. These studies define a novel mechanism for iT reg cell development and function, as well as a new strategy for controlling T reg cell plasticity.

Transthyretin amyloid goiter in a renal allograft recipient

Amyloid deposition in the follicular, perifollicular blood vessels, and thyroid stroma can occur in systemic forms of amyloidosis, although diffuse enlargement of the thyroid is generally not present. Marked, widespread enlargement of the thyroid gland with amyloid deposits or amyloid goiter is a rare condition reported in association with primary and secondary amyloidosis but has not been described in association with transthyretin amyloid deposition. Senile transthyretin amyloidosis is primarily associated with amyloid deposits in the heart, while the familial forms of amyloidosis due to transthyretin gene mutations are associated with deposits of amyloid in multiple tissues, classically giving rise to polyneuropathy. In this report, we describe the findings of parathyroid and lymph node amyloid deposits and amyloid goiter with transthyretin reactivity in a recipient of a kidney allograft, reportedly for renal amyloidosis, initially assumed clinically to be due to inflammatory bowel disease-related secondary amyloid deposition. This case underscores the importance of routine immunohistochemical classification of amyloid deposits for accurate diagnosis and to guide clinical management decisions.

Minimal-change nephrotic syndrome in a hematopoietic stem-cell transplant recipient

BACKGROUND

A 61-year-old woman received standard immunizations, including Haemophilus influenzae type B, diphtheria, tetanus toxoid, and unconjugated 23-valent pneumococcal vaccine (Pneumovax), Merck & Co., Inc., Whitehouse Station, NJ), 1 year after undergoing nonmyeloablative hematopoietic stem-cell transplantation for acute myelogenous leukemia. After 5 days, she developed fatigue with progressive weight gain and edema, and 14 days after immunization she presented with anasarca and was found to have acute renal failure and nephrotic proteinuria.

INVESTIGATIONS

Physical examination, serum chemistry, examination of urine sediment, renal ultrasound using Doppler scanning, 24 h urine collection, and renal biopsy.

DIAGNOSIS

Minimal-change nephrotic syndrome with acute tubular injury.

MANAGEMENT

Aggressive diuresis and oral corticosteroid therapy.

Sensitivity of P504S/??-Methylacyl-CoA Racemase (AMACR) Immunohistochemistry for the Detection of Prostate Carcinoma on Stored Needle Biopsies

Alpha methylacyl-CoA-racemase (AMACR), also known as P504S, has been widely used as a positive marker for the diagnosis of prostate carcinoma in clinical practice. The utility of this assay is highly dependent on the sensitivity of AMACR detection in routinely processed biopsies. It is common practice to store precut prostate biopsy sections. Hence, it is important to determine the effect on the immunoreactive of P504S/AMACR in stored, unstained glass slides as compared with freshly cut sections of paraffin-embedded tissue. The purpose of this study was to determine the sensitivity of AMACR immunostaining for the detection of prostate carcinoma on stored needle biopsies. A total of 63 prostate biopsies with prostate carcinoma were transferred onto glass slides, baked, and stored for 1.6 to 9.2 months. The Gleason scores were 3+3(6) (n=40) including 10 small focal carcinomas (< or = 1.0 mm), 4+3(7) (n=16), and 4+4(8) or higher (n=7). The slides were then stained with a monoclonal antibody to P504S, and the staining intensity was compared with sections cut from the same blocks just prior to immunostaining, without an intervening storage period. There was no loss of sensitivity of AMACR for prostate adenocarcinoma, regardless of the length of the storage interval. The sensitivity was preserved and was independent of Gleason scores. The sensitivity of AMACR for small foci of adenocarcinoma was also not affected by the length of storage. Overall, stored slides had no observable increase in nonspecific background staining over freshly cut sections. These results indicate that the time interval between mounting and staining does not affect the sensitivity of the AMACR immunohistochemistry (IHC) stain in the detection of prostate cancer even with small foci of carcinoma on needle biopsies.

Thrombospondin-1 binds to polyhistidine with high affinity and specificity

Thrombospondin-1 (TSP1) is a secreted trimeric glycoprotein of 450 kDa with demonstrated effects on cell growth, adhesion and migration. Its complex biological activity is attributed to its ability to bind to cell-surface receptors, growth factors and extracellular-matrix proteins. In this study, we used a (125)I solid-phase binding assay to demonstrate that TSP1 binds specifically to proteins containing polyhistidine stretches. Based on studies with three different six-histidine-containing recombinant proteins, we derived an average dissociation constant of 5 nM. The binding of (125)I-labelled TSP1 to these proteins was inhibited by peptides containing histidine residues, with the degree of competition being a function of the number of histidines within the peptide. Binding was not inhibited by excess histidine or imidazole, indicating that the imidazole ring is not sufficient for recognition by TSP1. Heparin was a potent inhibitor of binding with a K(i) of 50 nM, suggesting that the heparin-binding domain of TSP1 may be involved in this interaction. This was confirmed by the ability of a recombinant heparin-binding domain of TSP1 to directly compete for TSP1 binding to polyhistidine-containing proteins. Affinity chromatography with a polyhistidine-containing peptide immobilized on agarose revealed that TSP1 in platelet releasates is the major polypeptide retained on the six-histidine-peptide column. We conclude that TSP1 contains a high-affinity binding site for polyhistidine and this is likely to be the molecular basis for the observed binding of TSP1 to histidine-rich glycoprotein. The possibility that other polyhistidine-containing proteins also interact with TSP1 warrants further study.