Differences between κ and λ light chain amyloidosis analyzed by a pathologic scoring system

OBJECTIVES

Amyloid light chain (AL)-κ and AL-λ share common histopathologic changes; however, the potential difference in clinical manifestations, histologic findings, and clinical significance between the 2 subtypes remain unclear.

METHODS

In a retrospective study, 94 kidney biopsies for AL amyloidosis were evaluated using the composite scarring injury score (CSIS) and amyloid score (AS). Results were then compared between AL-κ and AL-λ.

RESULTS

Comparing AS and CSIS between AL-κ and AL-λ, the AS was significantly higher in AL-κ than in AL-λ, with 2 components of AS (capillary wall and vascular amyloid) scoring higher in AL-κ than in AL-λ, while mesangial and interstitial ASs were similar in the 2 cohorts. In addition, the proportion of periodic acid-Schiff strong-staining amyloid in AL-κ was markedly higher than in AL-λ. There was no significant difference in CSIS and its components between the 2 subtypes of AL amyloidosis.

CONCLUSIONS

Overall, AL-κ presents with higher serum creatinine and a higher AS score than AL-λ at biopsy, which may indicate a worse prognosis and be an important reference for clinical management.

Small vessel childhood primary angiitis of the central nervous system with positive anti-glial fibrillary acidic protein antibodies: a case report and review of literature

BACKGROUND

Small vessel childhood primary angiitis of the central nervous system (SV-cPACNS) is a rare disease characterized by inflammation within small vessels such as arterioles or capillaries.

CASE PRESENTATION

We report a case of SV-cPACNS in an 8-year-old boy confirmed by brain biopsy. This patient was also incidentally found to have anti-glial fibrillary acidic protein (GFAP) antibodies in the cerebrospinal fluid (CSF) but had no evidence of antibody-mediated disease on brain biopsy. A literature review highlighted the rarity of SV-cPACNS and found no prior reports of CSF GFAP-associated SV-cPACNS in the pediatric age group.

CONCLUSION

We present the first case of biopsy proven SV-cPACNS vasculitis associated with an incidental finding of CSF GFAP antibodies. The GFAP antibodies are likely a clinically insignificant bystander in this case and possibly in other diseases with CNS inflammation. Further research is needed to determine the clinical significance of newer CSF autoantibodies such as anti-GFAP before they are used for medical decision-making in pediatrics.

The characteristics of patients with kidney light chain deposition disease concurrent with light chain amyloidosis

The type of monoclonal light chain nephropathy is thought to be largely a function of the structural and physiochemical properties of light chains; hence most affected patients have only one light chain kidney disease type. Here, we report the first series of kidney light chain deposition disease (LCDD) concomitant with light chain amyloidosis (LCDD+AL), with or without light chain cast nephropathy (LCCN). Our LCDD+AL cohort consisted of 37 patients (54% females, median age 70 years (range 40-86)). All cases showed Congo red-positive amyloid deposits staining for one light chain isotype on immunofluorescence (62% lambda), and LCDD with diffuse linear staining of glomerular and tubular basement membranes for one light chain isotype (97% same isotype as the amyloidogenic light chain) and ultrastructural non-fibrillar punctate deposits. Twelve of 37 cases (about 1/3 of patients) had concomitant LCCN of same light chain isotype. Proteomic analysis of amyloid and/or LCDD deposits in eight revealed a single light chain variable domain mutable subgroup in all cases (including three with separate microdissections of LCDD and amyloid light chain deposits). Clinical data on 21 patients showed proteinuria (100%), hematuria (75%), kidney insufficiency and nephrotic syndrome (55%). Extra-kidney involvement was present in 43% of the patients. Multiple myeloma occurred in 68% (about 2/3) of these patients; none had lymphoma. On follow up (median 16 months), 63% developed kidney failure and 56% died. The median kidney and patient survivals were 12 and 32 months, respectively. LCDD+AL mainly affected patients 60 years of age or older. Thus, LCDD+AL could be caused by two pathological light chains produced by subclones stemming from one immunoglobulin light chain lambda or kappa rearrangement, with a distinct mutated complementary determining region.

Disseminated craniospinal low-grade glioma in a patient with NF-1 without optic pathway pathology: illustrative case

BACKGROUND

Neurofibromatosis type 1 (NF-1) is a neurocutaneous autosomal dominant disorder that predisposes patients to develop intracranial low-grade gliomas (LGGs). Most LGGs in patients with NF-1 involve the optic pathway but can arise anywhere throughout the central nervous system. NF-1–related disseminated pediatric LGG (dPLGG) in the absence of a dominant optic pathway glioma has not been described.

OBSERVATIONS

The authors discussed a case of a 10-year-old boy who presented with consideration for biopsy with nonoptic pathway PLGG with craniospinal dPLGG in the setting of NF-1. The patient’s primary lesion, located in the right medulla, was initially treated with surveillance before induction chemotherapy with carboplatin and vincristine was initiated. However, surveillance imaging demonstrated significant increase in size and enhancement, and subsequent craniospinal imaging demonstrated extensive nodular dissemination in the cervicothoracic spine. A biopsy and molecular testing were subsequently performed to further evaluate the tumor, and the patient was diagnosed with dPLGG with CDKN2A deletion.

LESSONS

Thorough craniospinal magnetic resonance imaging evaluation and biopsy in nonoptic pathway–dominant brain lesions in NF-1 are warranted in patients with atypical clinical and radiological findings in whom standard chemotherapeutic therapy fails.

Restless Legs Syndrome Shows Increased Silent Postmortem Cerebral Microvascular Disease With Gliosis

Background

Patients with restless legs syndrome (RLS) have increased silent microvascular disease by magnetic resonance imaging. However, there has been no previous autopsy confirmation of these magnetic resonance imaging findings. RLS is also frequently associated with inflammatory and immunologically mediated medical disorders. The postmortem cortex in patients with RLS was therefore evaluated for evidence of microvascular and immunological changes.

Methods and Results

Ten microvascular injury samples of precentral gyrus in 5 patients with RLS (3 men, 2 women; mean age, 81 years) and 9 controls (2 men, 7 women; mean age, 90 years) were studied by hematoxylin and eosin stains in a blinded fashion. None of the subjects had a history of stroke or neurologic insults. In a similar manner, the following immunohistochemistry stains were performed: (1) glial fibrillary acidic protein (representing gliosis, reactive change of glial cells in response to damage); (2) CD3 (a T‐cell marker); (3) CD19 (a B‐cell marker); (4) CD68 (a macrophage marker); and (5) CD117 (a mast cell marker). Patients with RLS had significantly greater silent microvascular disease (P=0.015) and gliosis (P=0.003). T cells were increased in RLS compared with controls (P=0.009) and tended to colocalize with microvascular disease (P=0.003). Other markers did not differ. There was no correlation between microvascular lesion load and RLS severity or duration.

Conclusions

Patients with RLS had statistically significantly more silent cerebral microvascular disease and gliosis than controls compatible with previous magnetic resonance imaging studies and with studies showing a link between RLS and hypertension, clinical stroke, and cardiovascular disease. T‐cell invasion may be a secondary phenomenon.

Case Report: Immune Dysregulation Due to Toxoplasma gondii Reactivation After Allogeneic Hematopoietic Cell Transplant

Disseminated toxoplasmosis is an uncommon but highly lethal cause of hyperferritinemic sepsis after hematopoietic cell transplantation (HCT). We report two cases of disseminated toxoplasmosis from two centers in critically ill adolescents after HCT: a 19-year-old who developed fever and altered mental status on day +19 after HCT and a 20-year-old who developed fever and diarrhea on day +52 after HCT. Both patients developed hyperferritinemia with multiple organ dysfunction syndrome and profound immune dysregulation, which progressed to death despite maximal medical therapies. Because disseminated toxoplasmosis is both treatable and challenging to diagnose, it is imperative that intensivists maintain a high index of suspicion for Toxoplasma gondii infection when managing immunocompromised children, particularly in those with known positive T. gondii serologies.

Acute Rejection of a Kidney Transplant in a Patient With Common Variable Immunodeficiency: A Case Report

Common variable immunodeficiency is a primary immunodeficiency characterized by hypogammaglobulinemia and recurrent bacterial infections. We report a case of a 44-year-old male patient with end-stage renal disease and an established diagnosis of common variable immunodeficiency who underwent a living unrelated kidney transplant. He remained nearly infection free on maintenance immunoglobulin replacement. However, his posttransplant course was complicated by acute rejection that ultimately led to allograft loss. This case illustrates the challenge of transplantation in this patient population because of the delicate balance that must be achieved between maintaining adequate immunosuppression and minimizing the risk of infection.

Drug-induced nephropathies

Drugs are associated frequently with the development of various types of acute and chronic kidney diseases. Nephrotoxicity is associated most commonly with injury in the tubulointerstitial compartment manifested as either acute tubular injury or acute interstitial nephritis. A growing number of reports has also highlighted the potential for drug-induced glomerular disease, including direct cellular injury and immune-mediated injury. Recognition of drug-induced nephropathies and rapid discontinuation of the offending agents are critical to maximizing the likelihood of renal function recovery. This review will focus on the pathology and pathogenesis of drug-induced acute interstitial nephritis and drug-induced glomerular diseases.

A wolf in another wolf's clothing

This case of infective endocarditis masquerading as mixed cryoglobulinemia in a man with a history of intravenous drug use (IVDU) and hepatitis C virus (HCV) highlights the importance of maintaining a broad differential and continually re-evaluating the working diagnosis as new information presents itself. The patient presented to an outside hospital and was treated for presumptive mixed cryoglobulinemia with corticosteroid therapy. When the patient did not improve, he was transferred to a tertiary care center for possible Rituximab and/or plasmapheresis. Further investigation revealed Enterococcus bacteremia with subsequent workup consistent with infective endocarditis (IE). This case highlights a diagnostic dilemma and demonstrates the importance of a thorough evaluation as it pertains to overlapping features of IE and mixed cryoglobulinemia.

Actinomycosis Mimicking Tolosa-Hunt Syndrome in a 6-Year-Old Boy: Case Report

Tolosa-Hunt syndrome is an idiopathic inflammatory process of the cavernous sinus or orbit manifesting as painful ophthalmoplegia. In this report, we detail the case of a 6-year-old boy who presented with several weeks of unilateral headache and diplopia. He was found to have an infiltrative process involving the bilateral cavernous sinuses and pituitary gland on MRI. Given a progressing infiltrative central nervous system process on repeat MRI and the development of cerebral salt wasting, a biopsy was performed revealing actinomycosis. To our knowledge, this is the first reported case of actinomycosis masquerading as Tolosa-Hunt syndrome in a child.

Retinoic Acid Signaling Coordinates Macrophage-Dependent Injury and Repair after AKI

Retinoic acid (RA) has been used therapeutically to reduce injury and fibrosis in models of AKI, but little is known about the regulation of this pathway and what role it has in regulating injury and repair after AKI. In these studies, we show that RA signaling is activated in mouse and zebrafish models of AKI, and that these responses limit the extent of injury and promote normal repair. These effects were mediated through a novel mechanism by which RA signaling coordinated the dynamic equilibrium of inflammatory M1 spectrum versus alternatively activated M2 spectrum macrophages. Our data suggest that locally synthesized RA represses proinflammatory macrophages, thereby reducing macrophage-dependent injury post-AKI, and activates RA signaling in injured tubular epithelium, which in turn promotes alternatively activated M2 spectrum macrophages. Because RA signaling has an essential role in kidney development but is repressed in the adult, these findings provide evidence of an embryonic signaling pathway that is reactivated after AKI and involved in reducing injury and enhancing repair.

Pulmonary hemorrhage with hematuria: do not forget IgA nephropathy

IgA nephropathy is the commonest cause of glomerulonephritis worldwide, and is usually a renal-limited disease. In rare cases, IgA nephropathy may also present with a pulmonary–renal syndrome in which pulmonary hemorrhage is a critical feature. Patients presenting with IgA nephropathy and pulmonary hemorrhage have high morbidity and are at high risk for mortality unless rapid immunosuppressive therapy is instituted. We present a case of IgA nephropathy complicated by pulmonary hemorrhage in which immunosuppressive therapy led to a good outcome, and review the literature on similar cases and the outcome of therapy.

p47(phox) contributes to albuminuria and kidney fibrosis in mice

Reactive oxygen species (ROS) have an important pathogenic role in the development of many diseases, including kidney disease. Major ROS generators in the glomerulus of the kidney are the p47(phox)-containing NAPDH oxidases NOX1 and NOX2. The cytosolic p47(phox) subunit is a key regulator of the assembly and function of NOX1 and NOX2 and its expression and phosphorylation are upregulated in the course of renal injury, and have been shown to exacerbate diabetic nephropathy. However, its role in nondiabetic-mediated glomerular injury is unclear. To address this, we subjected p47(phox)-null mice to either adriamycin-mediated or partial renal ablation-mediated glomerular injury. Deletion of p47(phox) protected the mice from albuminuria and glomerulosclerosis in both injury models. Integrin α1-null mice develop more severe glomerulosclerosis compared with wild-type mice in response to glomerular injury mainly due to increased production of ROS. Interestingly, the protective effects of p47(phox) knockout were more profound in p47(phox)/integrin α1 double knockout mice. In vitro analysis of primary mesangial cells showed that deletion of p47(phox) led to reduced basal levels of superoxide and collagen IV production. Thus, p47(phox)-dependent NADPH oxidases are a major glomerular source of ROS, contribute to kidney injury, and are potential targets for antioxidant therapy in fibrotic disease.

Malignant hypertension with thrombotic microangiopathy and persistent acute kidney injury (AKI)

Two cases of malignant hypertension presenting with acute kidney injury, thrombocytopenia and hemolytic anemia are presented. In both patients a prolonged duration of renal replacement therapy was required. The plasma levels of ADAMTS13 enzyme were not helpful in delineating the precise pathogenesis in both cases, as the decrements were not severe. We discuss the clinic-pathologic correlation of the biopsy findings and persistence of AKI.

Autopsy Renal Pathology

We provide an overview of assessment of the kidneys at autopsy, with special considerations for pediatric versus adult kidneys. We describe the approach to gross examination, tissue allocation when needed for additional studies of potential medical renal disease, the spectrum of congenital abnormalities of the kidneys and urinary tract, and approach to cystic diseases of the kidney. We also discuss common lesions seen at autopsy, including acute tubular injury, ischemic versus toxic contributions to this injury, interstitial nephritis, and common vascular diseases. Infections commonly involve the kidney at autopsy, and the key features and differential diagnoses are also discussed.

Hypertension is a major contributor to 20-hydroxyeicosatetraenoic acid-mediated kidney injury in diabetic nephropathy

In the kidney, 20-hydroxyeicosatetraenoic acid (20-HETE) is a primary cytochrome P450 4 (Cyp4)-derived eicosanoid that enhances vasoconstriction of renal vessels and induces hypertension, renal tubular cell hypertrophy, and podocyte apoptosis. Hypertension and podocyte injury contribute to diabetic nephropathy and are strong predictors of disease progression. In this study, we defined the mechanisms whereby 20-HETE affects the progression of diabetic nephropathy. We used Cyp4a14KO male mice that exhibit androgen-sensitive hypertension due to increased Cyp4a12-mediated 20-HETE production. We show that, upon induction of diabetes type 1 via streptozotocin injection, Cyp4a14KO male mice developed worse renal disease than streptozotocin-treated wild-type mice, characterized by increased albuminuria, mesangial expansion, glomerular matrix deposition, and thickness of the glomerular basement membranes. Castration blunted androgen-mediated Cyp4a12 synthesis and 20-HETE production, normalized BP, and ameliorated renal damage in diabetic Cyp4a14KO mice. Notably, treatment with a 20-HETE antagonist or agents that normalized BP without affecting Cyp4a12 expression and 20-HETE biosynthesis also ameliorated diabetes-mediated renal damage and albuminuria in Cyp4a14KO male mice. Taken together, these results suggest that hypertension is the major contributor to 20-HETE-driven diabetes-mediated kidney injury.

Epidermal growth factor receptor inhibition slows progression of diabetic nephropathy in association with a decrease in endoplasmic reticulum stress and an increase in autophagy

Previous studies by us and others have reported renal epidermal growth factor receptors (EGFRs) are activated in models of diabetic nephropathy. In the present study, we examined the effect of treatment with erlotinib, an inhibitor of EGFR tyrosine kinase activity, on the progression of diabetic nephropathy in a type 1 diabetic mouse model. Inhibition of renal EGFR activation by erlotinib was confirmed by decreased phosphorylation of EGFR and extracellular signal-related kinase 1/2. Increased albumin/creatinine ratio in diabetic mice was markedly attenuated by erlotinib treatment. Erlotinib-treated animals had less histological glomerular injury as well as decreased renal expression of connective tissue growth factor and collagens I and IV. Autophagy plays an important role in the pathophysiology of diabetes mellitus, and impaired autophagy may lead to increased endoplasmic reticulum (ER) stress and subsequent tissue injury. In diabetic mice, erlotinib-treated mice had evidence of increased renal autophagy, as indicated by altered expression and activity of ATG12, beclin, p62, and LC3A II, hallmarks of autophagy, and had decreased ER stress, as indicated by decreased expression of C/EBP homologous protein, binding immunoglobulin protein, and protein kinase RNA-like ER kinase. The mammalian target of rapamycin (mTOR) pathway, a key factor in the development of diabetic nephropathy and an inhibitor of autophagy, is inhibited by AMP-activated protein kinase (AMPK) activation. Erlotinib-treated mice had activated AMPK and inhibition of the mTOR pathway, as evidenced by decreased phosphorylation of raptor and mTOR and the downstream targets S6 kinase and eukaryotic initiation factor 4B. Erlotinib also led to AMPK-dependent phosphorylation of Ulk1, an initiator of mammalian autophagy. These studies demonstrate that inhibition of EGFR with erlotinib attenuates the development of diabetic nephropathy in type 1 diabetes, which is mediated at least in part by inhibition of mTOR and activation of AMPK, with increased autophagy and inhibition of ER stress.

Diabetic nephropathy induces alterations in the glomerular and tubule lipid profiles

Diabetic nephropathy (DN) is a major life-threatening complication of diabetes. Renal lesions affect glomeruli and tubules, but the pathogenesis is not completely understood. Phospholipids and glycolipids are molecules that carry out multiple cell functions in health and disease, and their role in DN pathogenesis is unknown. We employed high spatial resolution MALDI imaging MS to determine lipid changes in kidneys of eNOS(-/-) db/db mice, a robust model of DN. Phospholipid and glycolipid structures, localization patterns, and relative tissue levels were determined in individual renal glomeruli and tubules without disturbing tissue morphology. A significant increase in the levels of specific glomerular and tubular lipid species from four different classes, i.e., gangliosides, sulfoglycosphingolipids, lysophospholipids, and phosphatidylethanolamines, was detected in diabetic kidneys compared with nondiabetic controls. Inhibition of nonenzymatic oxidative and glycoxidative pathways attenuated the increase in lipid levels and ameliorated renal pathology, even though blood glucose levels remained unchanged. Our data demonstrate that the levels of specific phospho- and glycolipids in glomeruli and/or tubules are associated with diabetic renal pathology. We suggest that hyperglycemia-induced DN pathogenic mechanisms require intermediate oxidative steps that involve specific phospholipid and glycolipid species.

Mixed cryoglobulinemia and secondary membranoproliferative glomerulonephritis associated with ehrlichiosis

Ehrlichiosis is a tick-borne disease with diverse clinical presentations, ranging in severity from a flu-like illness with fever and myalgias to a serious systemic disease with multisystem organ failure. Nephrotic syndrome has been reported previously in two cases of human ehrlichiosis. A kidney biopsy revealed minimal change disease in one of those patients. Herein, we present the case of a 40-year-old man with ehrlichiosis who developed nephrotic syndrome, cryoglobulinemia, and secondary membranoproliferative glomerulonephritis (MPGN). The patient originally presented with shortness of breath, diffuse myalgias, headache, and lower extremity edema. He subsequently developed acute kidney injury and underwent kidney biopsy which showed MPGN and acute tubular injury. A tick-borne disease panel was positive for IgM and IgG to Ehrlichia chaffeensis. Serum testing revealed type 3 mixed cryoglobulinemia with no evidence of hepatitis C infection. The cryoprecipitate contained IgM and IgG antibodies to E. chaffeensis. Cryoglobulinemia is frequently associated with infections, particularly hepatitis C; however, our case is the first to describe ehrlichiosis associated with cryoglobulinemia and secondary MPGN.

Late recurrence of light chain deposition disease after kidney transplantation treated with bortezomib: a case report

BACKGROUND

Light chain deposition disease (LCDD) recurs frequently after renal transplantation with variable presentation.

CASE REPORT

We report the case of a 67-year-old Caucasian female with recurrence of LCDD after living-donor kidney transplantation. Bone marrow biopsy revealed kappa light chain-restricted population of plasma cells, and the patient met the criteria for multiple myeloma. Her renal function progressively worsened and she became dialysis dependent. She received 1 cycle of bortezomib along with intravenous dexamethasone. She was able to discontinue dialysis within 2 months, and at 1 year follow-up her renal function was stable.

CONCLUSION

Bortezomib has a role in the treatment of recurrent LCDD and multiple myeloma in kidney transplant patients. As opposed to traditional regimens, a short course may be beneficial.

A PTBA small molecule enhances recovery and reduces postinjury fibrosis after aristolochic acid-induced kidney injury

Phenylthiobutanoic acids (PTBAs) are a new class of histone deacetylase (HDAC) inhibitors that accelerate recovery and reduce postinjury fibrosis after ischemia-reperfusion-induced acute kidney injury. However, unlike the more common scenario in which patients present with protracted and less clearly defined onset of renal injury, this model of acute kidney injury gives rise to a clearly defined injury that begins to resolve over a short period of time. In these studies, we show for the first time that treatment with the PTBA analog methyl-4-(phenylthio)butanoate (M4PTB) accelerates recovery and reduces postinjury fibrosis in a progressive model of acute kidney injury and renal fibrosis that occurs after aristolochic acid injection in mice. These effects are apparent when M4PTB treatment is delayed 4 days after the initiating injury and are associated with increased proliferation and decreased G2/M arrest of regenerating renal tubular epithelial cells. In addition, there is reduced peritubular macrophage infiltration and decreased expression of the macrophage chemokines CX3Cl1 and CCL2. Since macrophage infiltration plays a role in promoting kidney injury, and since renal tubular epithelial cells show defective repair and a marked increase in maladaptive G2/M arrest after aristolochic acid injury, these findings suggest M4PTB may be particularly beneficial in reducing injury and enhancing intrinsic cellular repair even when administered days after aristolochic acid ingestion.

Vascular complications of fungal meningitis attributed to injections of contaminated methylprednisolone acetate

IMPORTANCE

Fungal meningitis due to injections of contaminated methylprednisolone acetate can present with vascular sequelae in immunocompetent individuals. This is particularly germane to neurologists because better recognition of the clinical characteristics of patients with fungal meningitis and ischemic stroke will provide more timely and efficient care.

OBSERVATIONS

In a case series, 3 patients presented to Vanderbilt University Medical Center in Nashville, Tennessee, with acute ischemic stroke and later received a diagnosis of fungal meningitis attributed to epidural injections of contaminated methylprednisolone. Of these 3 patients, 2 were women, and the mean age for all 3 was 75.3 years. Their medical records and imaging scans were reviewed. All 3 patients presented with acute ischemic strokes and had a history of epidural spinal injections of methylprednisolone for low back pain. All 3 patients had 1 or more traditional risk factors for stroke. There were differing vascular patterns of presentation: 2 patients presented with small-vessel (lacunar) infarctions, whereas 1 patient presented with a large-vessel infarct. Of these 3 patients, 2 died and underwent an autopsy, which revealed Exserohilum rostratum as the presumed cause of death. For 2 cases, fever and meningeal signs were absent at presentation.

CONCLUSIONS AND RELEVANCE

Patients with fungal meningitis may present with ischemic stroke detected on initial imaging scans. A definitive diagnosis should not delay early antifungal treatment.

Cocaine-induced acute interstitial nephritis: A case report and review of the literature

BACKGROUND

Acute tubular necrosis and pigment induced kidney injury are well described consequences of cocaine abuse. However, acute interstitial nephritis associated with cocaine use has been previously reported in only three patients.

CASE PRESENTATION

We present the case of a 49-year-old man who developed acute kidney injury from biopsy-proven interstitial nephritis after nasal insufflation of cocaine. Unlike prior reports, our patient remained non-oliguric and did not require renal replacement therapy.

CONCLUSIONS

Interstitial nephritis should be considered as a potential cause of acute kidney injury associated with cocaine use. The approach to management of cocaine associated acute kidney injury (AKI) may be different in patients with interstitial nephritis than for those with tubular necrosis or pigment induced renal injury.

Membranous glomerulopathy with superimposed pauci-immune necrotizing crescentic glomerulonephritis

We describe a 61-year-old woman with acute kidney injury, nephrotic range proteinuria and hematuria. Kidney biopsy showed membranous glomerulopathy (MG) with superimposed pauci-immune necrotizing crescentic glomerulonephritis (PNCGN). Coexistent MG and PNCGN is a rare occurrence. The diagnosis of such an exceptionally rare combination relies on the combination of renal biopsy findings and serologic testing. We also review previous reported cases and discuss possible pathogenesis of this rare dual glomerulopathy.

Deleting the TGF-β receptor attenuates acute proximal tubule injury

TGF-β is a profibrotic growth factor in CKD, but its role in modulating the kidney's response to AKI is not well understood. The proximal tubule epithelial cell, which is the main cellular target of AKI, expresses high levels of both TGF-β and its receptors. To determine how TGF-β signaling in this tubular segment affects the response to AKI, we selectively deleted the TGF-β type II receptor in the proximal tubules of mice. This deletion attenuated renal impairment and reduced tubular apoptosis in mercuric chloride-induced injury. In vitro, deficiency of the TGF-β type II receptor protected proximal tubule epithelial cells from hydrogen peroxide-induced apoptosis, which was mediated in part by Smad-dependent signaling. Taken together, these results suggest that TGF-β signaling in the proximal tubule has a detrimental effect on the response to AKI as a result of its proapoptotic effects.

Improvement of endothelial nitric oxide synthase activity retards the progression of diabetic nephropathy in db/db mice

Impaired endothelial nitric oxide synthase (eNOS) activity may be involved in the pathogenesis of diabetic nephropathy. To test this, we used the type 2 diabetic db/db mouse (BKS background) model and found impaired eNOS dimerization and phosphorylation along with moderate glomerular mesangial expansion and increased glomerular basement membrane (GBM) thickness at 34 weeks of age. Cultured murine glomerular endothelial cells exposed to high glucose had similar alterations in eNOS dimerization and phosphorylation. Treatment with sepiapterin, a stable precursor of the eNOS cofactor tetrahydrobiopterin, or the nitric oxide precursor L-arginine corrected changes in eNOS dimerization and phosphorylation, corrected permeability defects, and reduced apoptosis. Sepiapterin or L-arginine, administered to db/db mice from weeks 26 to 34, did not significantly alter hyperfiltration or affect mesangial expansion, but reduced albuminuria and GBM thickness, and decreased urinary isoprostane and nitrotyrosine excretion (markers of oxidative stress). Although there was no change in glomerular eNOS monomer expression, both sepiapterin and L-arginine partially reversed the defect in eNOS dimerization and phosphorylation. Hence, our results support an important role for eNOS dysfunction in diabetes and suggest that sepiapterin supplementation might have therapeutic potential in diabetic nephropathy.

Isometric tubular vacuolization in renal transplant recipient: the first case report in Thailand

Cyclosporine can cause acute and chronic nephrotoxicity. Renal biopsy is a reliable tool for the diagnosis of cyclosporine nephrotoxicity. The authors report a 56-year-old Thai female with a history of end-stage renal disease who underwent cadaveric renal transplantation. A transplanted kidney biopsy was performed on day 9 post-transplant to identify the cause of delayed graft function. Light and electron microscopic findings revealed widespread (> 50% involvement) numerous tubules filled with uniformly-sized vacuoles in cytoplasm (isometric vacuolization). Serum cyclosporine trough level was 534 ng/mL. Neither acute rejection nor acute tubular necrosis was seen. Diagnosis of acute cyclosporine nephrotoxicity was made. Isometric vacuolization in more than 50% involvement of the tubules is rare (3%) in biopsy specimens. The tubular isometric vacuolization might not have the strong impact to the long term graft outcome. This is the first case report of isometric tubular vacuolization due to cyclosporine toxicity in renal transplant recipient in Thailand.

Integrin α1/Akita double-knockout mice on a Balb/c background develop advanced features of human diabetic nephropathy

Animal models that mimic human diabetic nephropathy are useful to identify key factors in pathogenesis of this disease, as well as the development of new therapies. Several mouse models of diabetes have features of human diabetic nephropathy, yet none of these completely fulfill the Animal Models of Diabetes Complications Consortium criteria and completely reproduce pathological and functional features of the human disease. The Akita mouse carries a mutation in the insulin-2 gene and, to date, only survives as heterozygotes that develop spontaneous type 1 diabetes. Here we show that Akita mice with mutation of both insulin-2 alleles (Akita knockout (KO)) survive if crossed onto the Balb/c background. These mice develop hyperglycemia, more severe albuminuria, and mesangial sclerosis compared with heterozygous mice on the same genetic background. Interestingly, crossing these AkitaKO mice with integrin α1KO mice, a model of exacerbated glomerulosclerosis after injury and also on the Balb/c background, resulted in a 16-fold increase in albuminuria, significant mesangial matrix expansion, nodular and diffuse glomerulosclerosis, and a 2-fold increase in glomerular basement membrane thickening when compared with nondiabetic mice. Moreover, a significant decline in glomerular filtration was evident in the α1KOAkitaKO mice at 6 months of age. Thus, the integrin α1KOAkitaKO Balb/c mouse represents a promising model presenting with most features of human diabetic nephropathy.

Restless legs syndrome--theoretical roles of inflammatory and immune mechanisms

Theories for restless legs syndrome (RLS) pathogenesis include iron deficiency, dopamine dysregulation and peripheral neuropathy. Increased prevalence of small intestinal bacterial overgrowth (SIBO) in controlled studies in RLS and case reports of post-infectious RLS suggest potential roles for inflammation and immunological alterations. A literature search for all conditions associated with RLS was performed. These included secondary RLS disorders and factors that may exacerbate RLS. All of these conditions were reviewed with respect to potential pathogenesis including reports of iron deficiency, neuropathy, SIBO, inflammation and immune changes. A condition was defined as highly-associated if there was a prevalence study that utilized an appropriate control group. Small case reports were recorded but not included as definite RLS-associated conditions. Fifty four diseases, syndromes and conditions have been reported to cause and/or exacerbate RLS. Of these, 38 have been reported to have a higher prevalence than age-matched controls, 9 have adequate sized reports and have general acceptance as RLS-associated conditions and 7 have been reported in case report form. Overall, 42 of the 47 RLS-associated conditions (89%) have also been associated with inflammatory and/or immune changes. In addition, 43% have been associated with peripheral iron deficiency, 40% with peripheral neuropathy and 32% with SIBO. Most of the remaining conditions have yet to be studied for these factors. The fact that 95% of the 38 highly-associated RLS conditions are also associated with inflammatory/immune changes suggests the possibility that RLS may be mediated or affected through these mechanisms. Inflammation can be responsible for iron deficiency and hypothetically could cause central nervous system iron deficiency-induced RLS. Alternatively, an immune reaction to gastrointestinal bacteria or other antigens may hypothetically cause RLS by a direct immunological attack on the central or peripheral nervous system.

A concurrence of light and heavy chain deposition disease and diabetic nephropathy

A 56-year-old female patient was clinically characterized by heavy proteinuria, anemia, hypertension, and no detectable monoclonal protein in serum or urine. She had a history of diabetes with retinopathy and hypertension. Histological investigation of renal biopsy specimens revealed nodular glomerulosclerosis. Light microscopic examination did not allow discrimination between diabetic glomerulosclerosis and monoclonal immunoglobulin deposition disease (MIDD). Immunofluorescent examination showed linear capillary wall and tubular basement membrane staining with kappa, and IgG staining. Electron-microscopic examination confirmed the amorphous material along the glomerular basement. Based on these findings, the diagnosis of light chain and heavy chain monoclonal immunoglobulin deposition disease (LHCDD) and diabetic nephropathy was made. At the present after the 7th course of melphalan and prednisolone treatment, her renal function and proteinuria have progressively improved.

A two-phase study model for the standardization of HER2 immunohistochemical assay on invasive ductal carcinoma of the breast

OBJECTIVES

To develop and verify a standardized protocol for HER2 immunohistochemical assays on invasive ductal carcinoma of the breast in Thailand.

MATERIAL AND METHOD

A two-phase study approach was employed. In the Phase One, after verifying the proposed protocol that adopted the HercepTest procedure using readily available primary antibodies, CB11 and A0485, Lab 1 performed the HER2 immunohistochemical staining for 137 cases of invasive ductal carcinoma twice with two types of the antibody. Nine pathologists from 8 centers independently examined and scored all the 2 x 137 stained slides that were blinded for antibody type. Interobserver reliability was calculated using pair-wise kappa. Following discussion of the results, the Phase Two study was planned. Lab 2 and Lab 3 independently performed the HER2 staining according to the protocol for 60 invasive breast carcinoma cases. The same group of pathologists scored 2 x 60 stained slides that were masked for laboratories. Interobserver reliability and interlaboratory agreement from each pathologist were calculated using kappa statistics. Three interpreted categories--namely negative, equivocal and positive tests were used in the analyses.

RESULTS

Phase One study showed interobserver agreement between pairs varied from kappa 0.75 (95%CI, 0.68-0.82) to 0.06 (95%CI, 0-0.14) while Phase Two study obtained pair-wise kappa scores ranged from 0.84 (95%CI, 0. 80-0.89) to 0. 65 (95%CI, 0.59-0.71). Interlaboratory kappa for each pathologist was 0.67 (95%CI, 0.61-0.73).

CONCLUSION

The standardization of HER2 immunohistochemical assay was achieved through this two-phase study model. It had added benefits of improving pathologists' expertise and verifying the HER2 testing protocol to be used in Thailand.

Epilepsy surgery in children and adolescence; Phramongkutklao College of Medicine's experience

OBJECTIVES

To evaluate the safety and efficacy of epilepsy surgery in children and adolescence at Comprehensive Epilepsy Center, Phramongkutklao College of Medicine.

MATERIAL AND METHOD

Children and adolescents, who underwent epilepsy surgery at Comprehensive Epilepsy Center, Phramongkutklao College of Medicine were identified from the epilepsy surgery database. The following parameters were evaluated: age at surgery, duration of seizure prior to surgery, presurgical work up, presurgical as well as postsurgical neurological/ seizure status and neuropathology (if applicable). All follow-up data were obtained through clinic visits.

RESULTS

Fifteen children who underwent epilepsy surgery between January 1, 2003 and March 31, 2005 were identified. Age at surgery ranged from 2.5 years to 19 years (mean age=8.2 years). Seizure duration prior to surgery ranged from 1 year to 17 years (mean=4.7 years). Eight patients (53%) had partial seizures and underwent excisional procedures [5 temporal lobectomy, 2 left frontal corticectomy, and 1 left functional hemispherectomy]. Seven patients (47%) had generalized seizures and underwent anterior 2/3 corpus callosotomy. Pathological information was available for all 8 cases with partial epilepsy. Four out of eight cases with pathological information demonstrated cortical dysplasia, four revealed hippocampal sclerosis, and two patients had dysembryoplastic neuroepithelial tumor (DNET). At follow-up, all 5 patients with temporal lobectomy and a child who underwent functional hemispherectomy were seizure free (follow up period 3-31 months). Two children with extratemporal resective surgery [left frontal corticectomy] showed remarkable improvement with rare breakthrough seizures (follow up period= 3 and 19 months respectively). Four out of seven patients with corpus collosotomy had worthwhile improvement of seizures (follow up period=4-19 months), while another two children were seizure free during short-termed follow up postoperatively (follow up period=1 and 2 months). All patients did not have significant neurological deterioration or worsening of seizure after the surgery.

CONCLUSION

Resective epilepsy surgery in Thai pediatric populations in the authors' experience seems to be safe and effective in selected patients. Most children who underwent callosotomy had a significant reduction in intensity and frequency of tonic, atonic, and tonic-clonic seizures. Dual pathology was common in refractory temporal lobe epilepsy with hippocampal sclerosis. Although the study sample was small, it did advocate several larger studies with the same findings.

September 2003: a 79-year-old female with right frontal lobe mass

The September2003 COM. A 79-year-old woman with prior history of breast cancer and meningioma presented with headache, memory changes and sleep disturbance for four months. CT and MRI revealed a large cystic mass in the right frontal lobe with heterogeneity and an enhancing border. She had a craniotomy and resection of tumor. The tumor was histologically consistent with gliosarcoma. Gliosarcomas exhibit clinical features and genetic profiles similar to primary (de novo) glioblastoma. Gliosarcomas have the same as prognosis as glioblastoma multiforme.

Inflammatory Pseudotumor of the Temporal Bone

OBJECTIVE

To characterize the clinical presentation, imaging characteristics, intraoperative findings, and key histopathologic features of inflammatory pseudotumors of the temporal bone. Findings from an index case are presented, and the literature is reviewed for comparison.

STUDY DESIGN

Retrospective case review.

SETTING

University tertiary referral center.

PATIENTS

Cases were identified by review of surgical specimens from the temporal bone and lateral skull base with histopathologic confirmation. A single case was identified at our institution. Nine additional cases were identified in the literature; clinical features were reviewed.

INTERVENTION

Of reported cases, treatment consisted of complete surgical excision in eight cases and subtotal excision in one. The index patient underwent surgical excision with postoperative corticosteroid therapy for adjacent meningeal involvement, after histopathologic interpretation. Corticosteroids were administered to one patient with residual microscopic tumor, and external beam radiotherapy was used for residual/recurrent disease in one case.

RESULTS

The lesions were typically locally aggressive with extensive bony erosion. Three cases (33%) demonstrated labyrinthine and otic capsule involvement. Four cases (44%) involved the facial nerve. Characteristic histopathologic features included fibroblastic proliferation and a mixed inflammatory cell infiltrate in all cases. Mitotic figures, nuclear pleomorphism, and necrosis were rare or nonexistent.

CONCLUSIONS

Inflammatory pseudotumors of the temporal bone are rare but aggressive lesions. Therapy should consist of surgical excision with steroids reserved for residual or intracranial disease or in patients in whom surgery is not an option. These lesions must be differentiated from other infectious, granulomatous, and neoplastic lesions on the basis of histopathologic and immunohistochemical findings.

Monoclonal gammopathy: significance and possible causality in renal disease

BACKGROUND

Patients with monoclonal gammopathy can develop a variety of related renal lesions or possibly have kidney disease unrelated to their monoclonal gammopathy. We characterized the spectrum of renal diseases associated with monoclonal gammopathy and renal diseases.

METHODS

Patients who underwent renal biopsy and had monoclonal gammopathy on serum and/or urine electrophoresis and/or had a renal biopsy diagnosis related to paraprotein (cryoglobulinemic glomerulonephritis [CG], monoclonal immunoglobulin deposition disease [MIDD], light chain cast nephropathy [CN], or light chain amyloidosis [AL]) were identified.

RESULTS

One hundred twenty-one patients met the inclusion criteria and were classified as having renal disease related or unrelated to monoclonal gammopathy. Among 66 cases of renal disease related to monoclonal gammopathy, diagnoses were CG (30.3%), MIDD (28.8%), CN (19.7%), AL (19.7%), and CN plus MIDD (1.5%). Among patients with monoclonal gammopathy in serum and/or urine (n = 87), 32 patients (36.8%, included in listing above) had related renal disease. Among 55 patients with monoclonal gammopathy and unrelated renal disease (63.2% of all patients with monoclonal gammopathy), various lesions were found, including diabetic nephropathy (18.1%), focal segmental glomerulosclerosis (18.1%), arterionephrosclerosis (12.7%), membranous glomerulonephritis (9.0%), minimal change disease (7.3%), various immune complex diseases, interstitial nephritis, or nonspecific changes.

CONCLUSION

The majority of patients with serum and/or urine monoclonal gammopathy who undergo renal biopsy have disease unrelated to monoclonal gammopathy deposition. This likely reflects the high frequency of monoclonal gammopathy of undetermined significance in older patients and the frequent use of serum and/or urine protein electrophoresis as screening tools in adult patients with renal disease.

Local cryoglobulin deposition in primary central nervous system lymphoma

Primary central nervous system lymphomas (PCNSLs) represent malignant non-Hodgkin's B-cell lymphomas confined to the central nervous system. Recent years have brought a dramatic increase in the frequency of PCNSL in the immunocompromised and immunocompetent populations. Cryoglobulins are cold-precipitable immunoglobulins associated with a number of infectious, autoimmune, and neoplastic disorders. Although it is known that patients with hematologic malignancies (eg, B-cell lymphomas, chronic lymphocytic leukemia, plasma cell dyscrasias) may have cryoglobulinemias and cryoglobulin deposition in several organs (eg, kidney, liver skin, blood vessels, peripheral nervous system), PCNSL associated with cryoglobulin deposition has not been previously described. This report demonstrates localized cryoglobulin deposition within the tumor bed in an immunocompetent patient with PCNSL.

Microangiopathic injury and augmented PAI-1 in human diabetic nephropathy

BACKGROUND

Microvascular injury and mesangial dysfunction contribute to the pathogenesis of diabetic glomerulosclerosis. We investigated the extent of microvascular injury characterized by fragmented red blood cells (RBCs) in the mesangium of glomeruli in diabetic nephropathy, and its clinicopathologic significance. We also investigated the possible contributions of plasminogen activator inhibitor-1 (PAI-1), which has been implicated in thrombosis and sclerosis, and the novel steroid receptor superfamily member, peroxisome proliferator-activated receptorgamma (PPARgamma), implicated in monocyte-foamy macrophage transformation in atherosclerosis and improved insulin responsiveness in diabetes.

METHODS

Sixty-four diabetic nephropathy (DN) cases in our renal biopsy files at VUMC, diagnosed between 1997 and 1999, were reviewed. Patients were classified based on the presence or absence of fragmented RBCs in the mesangium (M+, M-). PAI-1 and PPARgamma immunostaining was performed with double staining for the macrophage marker CD68.

RESULTS

M+ lesions were present in 21.9% of cases, and in positive cases, involved on average 10.2 +/- 2.1% of glomeruli. M+ patients were 40- to 78-years-old (mean +/- SD, 60.4 +/- 9.8), the female/male ratio was 2.5, and the white/black ratio was 6. In M-, the patients' ages ranged from 29 to 81 years (57.6 +/- 13.3, P = NS vs. M+), the female/male ratio was 0.5 (P < 0.05 vs. M+), and the white/black ratio was 2.3 (P = 0.1 vs. M+). Mean 24-hour urine protein in M+ was 9.9 +/- 13.6 g/24 h, versus 4.0 +/- 2.8 g/24 h in M- (P < 0.05). The fragmented RBCs in M+ cases localized exclusively within Kimmelstiel-Wilson nodules. PAI-1 and PPARgamma immunostaining was increased in areas of sclerosis in arteries and glomeruli, with expression of both in glomerular mesangial, parietal and visceral epithelial cells. Infiltrating macrophages in glomeruli were PPARgamma negative, contrasting positivity in macrophages in control cases of carotid artery plaque and in renal interstitial macrophages. The Kimmelstiel-Wilson nodules in M+ patients showed increased PAI-1 staining.

CONCLUSIONS

Mesangial RBC fragments are indicative of microvascular injury and mesangiolysis in DN and are associated with worse proteinuria, and possible worse prognosis. Possible pathogenic mechanisms involve the fibrinolytic/proteolytic system and locally activated PAI-1.

Melanotic neuroectodermal tumor of infancy discovered after head trauma

Melanotic neuroectodermal tumor of infancy (MNTI) is a rare neoplasm that generally arises in the maxilla during the first year of life. Involvement of bones of the cranial vault or brain is extremely rare. We describe a 7-month-old black female who presented after falling out of bed onto a concrete floor. Subsequently, she developed an anterior frontal mass that enlarged over several days. Radiographs of the skull at her local hospital showed a depressed right frontal skull fracture. However, computerized tomography of the head (reviewed at our institution) revealed a slightly hyperdense extra-axial mass which crossed the anterior frontal midline, widening the metopic suture and extending into the anterior subgaleal scalp. Hyperostosis of the adjacent frontal calvarium was also present. A craniotomy revealed a dark, 1.5-cm calcified epidural lesion with some features of an unusual hematoma. Microscopic evaluation revealed a chronic hematoma and MNTI. The tumor recurred within a year. MNTI should be included in the differential diagnosis of epidural and skull lesions in infants.