Treatment with IFN-{alpha}, -{beta}, or -{gamma} is associated with collapsing focal segmental glomerulosclerosis

Renal comorbidities in collapsing variant focal segmental glomerulosclerosis: more than a coincidence?

BACKGROUND

Collapsing focal segmental glomerulosclerosis (FSGS) has various underlying etiologies and often leads to renal failure. The impact of biopsy-proven renal comorbidities in promoting collapsing glomerulopathy (CG) has not been systematically evaluated in large comparative studies. Those data are reported here.

METHODS

Biopsies with the initial diagnosis of CG in native (n = 321) or transplant kidneys (n = 30) were identified in the University of North Carolina nephropathology database (1 January 2011 to 1 January 2016). Two cohorts were defined: 'sole' CG without and 'accompanied' CG with significant morphologic renal comorbidities. Tip-variant FSGS (T-FSGS) and time-matched biopsies served as control cohorts for comparative analyses.

RESULTS

CG was significantly more common in native (4.4%) and transplant biopsies (4.1%) compared with T-FSGS (0.7 and <0.1%, respectively, difference versus CG P < 0.01). 'Associated' disease was significantly more common in CG (native: 151/321; 47.0%, transplant: 21/30; 70%, P < 0.05) versus T-FSGS (native: 14/51; 27.5%, transplant: exceptional; all differences versus CG P < 0.05). In native biopsies with 'accompanied' CG but not in control groups, stenosing vasculopathies including thrombotic microangiopathies were significantly more prevalent (P < 0.01). In transplants, the high incidence of 'accompanied' CG was linked to de novo diseases, mainly rejection and vascular injury. In native kidneys, membranous glomerulopathies were prevalent in 'accompanied' T-FSGS (36%) and CG (14%) (difference versus time-matched controls P < 0.01 and P < 0.05, respectively); they were uncommon in transplants.

CONCLUSIONS

CG but not T-FSGS shows a high rate of comorbidities, with prominent vasculopathies presumably driving 'ischemic' CG-specific glomerular injury and also the disease course. These findings facilitate future studies into therapy, prognosis and reversibility of 'accompanied' CG.

APOL1 risk variants and the development of HIV-associated nephropathy

HIV-associated nephropathy (HIVAN) remains a concern among untreated HIV patients, notably of African descent, as patients can reach end-stage renal disease within 3 years. Two variants (G1 and G2) of the APOL1 gene, common in African populations to protect against African sleeping sickness, have been associated with an increased risk of several glomerular disorders including HIVAN, hypertension-attributed chronic kidney disease, and idiopathic focal segmental glomerulosclerosis and are accordingly named renal risk variants (RRVs). This review examines the mechanisms by which APOL1 RRVs drive glomerular injury in the setting of HIV infection and their potential application to patient management. Innate antiviral mechanisms activated by chronic HIV infection, especially those involving type 1 interferons, are of particular interest as they have been shown to upregulate APOL1 expression. Additionally, the downregulation of miRNA 193a (a repressor of APOL1) is also associated with the upregulation of APOL1. Interestingly, glomerular damage affected by APOL1 RRVs is caused by both loss- and gain-of-function changes in the protein, explicitly characterizing these effects. Their intracellular localization offers a further understanding of the nuances of APOL1 variant effects in promoting renal disease. Finally, although APOL1 variants have been recognized as a critical genetic player in mediating kidney disease, there are significant gaps in their application to patient management for screening, diagnosis, and treatment.

Case Report: Renal Failure due to Focal Segmental Glomerulosclerosis in a Patient with Murine Typhus

Murine typhus is a flea-borne rickettsiosis caused by Rickettsia typhi. When severe, endothelial dysfunction can lead to acute kidney injury secondary to prerenal azotemia or acute tubular necrosis. Here, we describe an unusual cause of kidney injury during the course of murine typhus-focal segmental glomerulosclerosis.

Persistent Interferon Production by Double Negative T Cells and Collapsing Focal Segmental Glomerulosclerosis

Collapsing glomerulopathy has multiple associations, including viral infections, medications like bisphosphonates and interferon, autoimmune diseases, and genetic predisposition. We report a case of collapsing focal segmental glomerulosclerosis associated with persistently high levels of interferon gamma produced by T-cell receptor αβ (+), CD4- CD8- (double negative) T lymphocytes that progressed despite treatment and improvement of other cytokine levels. Double negative T cells are elevated and activated in autoimmune lymphoproliferative syndrome (ALPS). Production of elevated interferon gamma levels from double negative T cells in ALPS despite treatment provides insight to the pathophysiology of collapsing glomerulopathy, guiding future research for collapsing glomerulopathy.

Focal Segmental Glomerulosclerosis: State-of-the-Art and Clinical Perspective

Focal segmental glomerulosclerosis (FSGS) is a histological pattern of glomerular injury, rather than a single disease, that is caused by diverse clinicopathological entities with different mechanisms of injury with the podocyte as the principal target of lesion, leading to the characteristic sclerotic lesions in parts (i.e., focal) of some (i.e., segmental) glomeruli. The lesion of FSGS has shown an increasing prevalence over the past few decades and is considered the most common glomerular cause leading to ESKD. Primary FSGS, which usually presents with nephrotic syndrome, is thought to be caused by circulating permeability factors that have a main role in podocyte foot process effacement. Secondary forms of FSGS include maladaptive FSGS secondary to glomerular hyperfiltration such as in obesity or in cases of loss in nephron mass, virus-associated FSGS, and drug-associated FSGS that can result in direct podocyte injury. Genetic FSGS is increasingly been recognized and a careful evaluation of patients with atypical primary or secondary FSGS should be performed to exclude genetic causes. Unlike primary FSGS, secondary and genetic forms of FSGS do not respond to immunosuppression and tend not to recur after kidney transplantation. Distinguishing primary FSGS from secondary and genetic causes has a prognostic significance and is crucial for an appropriate management. In this review, we examine the pathogenesis, clinical approach to distinguish between the different causes, and current recommendations in the management of FSGS.

Kidney Biopsy Findings in Patients with COVID-19

BACKGROUND

Coronavirus disease 2019 (COVID-19) is thought to cause kidney injury by a variety of mechanisms. To date, pathologic analyses have been limited to patient reports and autopsy series.

METHODS

We evaluated biopsy samples of native and allograft kidneys from patients with COVID-19 at a single center in New York City between March and June of 2020. We also used immunohistochemistry, in situ hybridization, and electron microscopy to examine this tissue for presence of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2).

RESULTS

The study group included 17 patients with COVID-19 (12 men, 12 black; median age of 54 years). Sixteen patients had comorbidities, including hypertension, obesity, diabetes, malignancy, or a kidney or heart allograft. Nine patients developed COVID-19 pneumonia. Fifteen patients (88%) presented with AKI; nine had nephrotic-range proteinuria. Among 14 patients with a native kidney biopsy, 5 were diagnosed with collapsing glomerulopathy, 1 was diagnosed with minimal change disease, 2 were diagnosed with membranous glomerulopathy, 1 was diagnosed with crescentic transformation of lupus nephritis, 1 was diagnosed with anti-GBM nephritis, and 4 were diagnosed with isolated acute tubular injury. The three allograft specimens showed grade 2A acute T cell-mediated rejection, cortical infarction, or acute tubular injury. Genotyping of three patients with collapsing glomerulopathy and the patient with minimal change disease revealed that all four patients had APOL1 high-risk gene variants. We found no definitive evidence of SARS-CoV-2 in kidney cells. Biopsy diagnosis informed treatment and prognosis in all patients.

CONCLUSIONS

Patients with COVID-19 develop a wide spectrum of glomerular and tubular diseases. Our findings provide evidence against direct viral infection of the kidneys as the major pathomechanism for COVID-19-related kidney injury and implicate cytokine-mediated effects and heightened adaptive immune responses.

Association of a de novo nonsense mutation of the TRIM8 gene with childhood-onset focal segmental glomerulosclerosis

BACKGROUND

Focal segmental glomerulosclerosis (FSGS) is an etiologically heterogeneous disorder. Genetic FSGS may be either limited to the kidney or part of a genetic syndrome with other systemic involvement. At least 21 and 34 genes have been reported for renal-limited and syndromic FSGS, respectively. The TRIM8 gene encodes a tripartite motif protein, which is an E3 ubiquitin-protein ligase that promotes proteasomal degradation of the suppressor of cytokine signaling 1 (SOCS1) and participates in the activation of interferon-gamma signaling. The TRIM8 gene is expressed in various tissues including the kidney and the central nervous system (CNS). An association between a mutation in the TRIM8 gene and childhood-onset FSGS has not been well established.

CASE-DIAGNOSIS

We describe an 8-year-old Hispanic male with infantile onset motor and developmental delay, seizures, and proteinuria secondary to FSGS. Next generation sequencing revealed a heterozygous de novo pathogenic variant in the TRIM8 gene (C1380T>A, p.Tyr460*). Immunohistochemical staining using anti-TRIM8 and anti-SOCS1 antibodies showed no significant TRIM8 expression and strong expression of SOCS1 in the renal biopsy tissue.

TREATMENT AND CONCLUSIONS

De novo truncating mutations of TRIM8 have been previously reported in childhood-onset epileptic encephalopathy. A molecular analysis of TRIM8 should be considered in children with FSGS and clinical abnormalities of the central nervous system.

Indirect effects of severe acute respiratory syndrome coronavirus 2 on the kidney in coronavirus disease patients

Among patients hospitalized for novel coronavirus disease (COVID-19), between 10 and 14% develop an acute kidney injury and around half display marked proteinuria and haematuria. Post-mortem analyses of COVID-19 kidney tissue suggest that renal tubular cells and podocytes are affected. Here we report two cases of collapsing glomerulopathy and tubulointerstitial lesions in living COVID-19 patients. Despite our use of sensitive reverse transcription polymerase chain reaction techniques in this study, we failed to detect the virus in blood, urine and kidney tissues. Our observations suggest that these kidney lesions are probably not due to direct infection of the kidney by severe acute respiratory syndrome coronavirus 2.

Apolipoprotein L-1 renal risk variants form active channels at the plasma membrane driving cytotoxicity

Recently evolved alleles of Apolipoprotein L-1 (APOL1) provide increased protection against African trypanosome parasites while also significantly increasing the risk of developing kidney disease in humans. APOL1 protects against trypanosome infections by forming ion channels within the parasite, causing lysis. While the correlation to kidney disease is robust, there is little consensus concerning the underlying disease mechanism. We show in human cells that the APOL1 renal risk variants have a population of active channels at the plasma membrane, which results in an influx of both Na⁺ and Ca²⁺. We propose a model wherein APOL1 channel activity is the upstream event causing cell death, and that the activate-state, plasma membrane-localized channel represents the ideal drug target to combat APOL1-mediated kidney disease.

The Role of Wnt Signalling in Chronic Kidney Disease (CKD)

Chronic kidney disease (CKD) encompasses a group of diverse diseases that are associated with accumulating kidney damage and a decline in glomerular filtration rate (GFR). These conditions can be of an acquired or genetic nature and, in many cases, interactions between genetics and the environment also play a role in disease manifestation and severity. In this review, we focus on genetically inherited chronic kidney diseases and dissect the links between canonical and non-canonical Wnt signalling, and this umbrella of conditions that result in kidney damage. Most of the current evidence on the role of Wnt signalling in CKD is gathered from studies in polycystic kidney disease (PKD) and nephronophthisis (NPHP) and reveals the involvement of β-catenin. Nevertheless, recent findings have also linked planar cell polarity (PCP) signalling to CKD, with further studies being required to fully understand the links and molecular mechanisms.

Nephrotoxicity in cancer treatment: An overview

Anticancer drug nephrotoxicity is an important and increasing adverse drug event that limits the efficacy of cancer treatment. The kidney is an important elimination pathway for many antineoplastic drugs and their metabolites, which occurs by glomerular filtration and tubular secretion. Chemotherapeutic agents, both conventional cytotoxic agents and molecularly targeted agents, can affect any segment of the nephron including its microvasculature, leading to many clinical manifestations such as proteinuria, hypertension, electrolyte disturbances, glomerulopathy, acute and chronic interstitial nephritis, acute kidney injury and at times chronic kidney disease. The clinician should be alert to recognize several factors that may maximize renal dysfunction and contribute to the increased incidence of nephrotoxicity associated with these drugs, such as intravascular volume depletion, the associated use of nonchemotherapeutic nephrotoxic drugs (analgesics, antibiotics, proton pump inhibitors, and bone-targeted therapies), radiographic ionic contrast media or radiation therapy, urinary tract obstruction, and intrinsic renal disease. Identification of patients at higher risk for nephrotoxicity may allow the prevention or at least reduction in the development and severity of this adverse effect. Therefore, the aim of this brief review is to provide currently available evidences on oncologic drug-related nephrotoxicity.

Nephrotoxic Chemotherapy Agents: Old and New

In the last several decades, advancements in chemotherapy have improved the overall survival of cancer patients. These agents, however, are associated with adverse effects, including various kidney lesions. This review summarizes the nephrotoxic potential of chemotherapy agents, old and new, as well as the different factors that contribute to kidney injury. Provided for each class of chemotherapy agent is the associated kidney lesion and a brief discussion of clinical manifestation, mechanism of action, and possible treatment when available. Understanding the nephrotoxic potential of these agents have on the kidneys is imperative for both the oncologist and the nephrologist to properly care for cancer patients and ensure their best outcomes.

Nephrotoxicity of Antimicrobials and Antibiotics

Medication-induced nephrotoxicity remains one of the most common causes of acute kidney injury (AKI) among hospitalized patients. Within the extensive group of medications associated with AKI, antibiotics and other antimicrobials are well recognized triggers of structural and functional renal impairment. Clinical manifestations range from mild forms of tubular injury to significant deterioration of kidney function requiring acute renal replacement therapy. Several mechanisms are described, although the most frequent are acute interstitial nephritis, acute tubular necrosis, intratubular crystal deposition, and proximal/distal tubulopathy with electrolyte wasting abnormalities. General risk factors for antimicrobial-induced AKI include pre-existing chronic kidney disease, and concomitant use of medication with nephrotoxic potential. Prevention and early recognition of AKI represent the standard approach to mitigate AKI and avoid morbidity.

Broad spectrum of interferon-related nephropathies-glomerulonephritis, systemic lupus erythematosus-like syndrome and thrombotic microangiopathy: A case report and review of literature

BACKGROUND

Interferons (IFNs) are characterized by a wide range of biological effects, which justifies their potential therapeutic use in several pathologies, but also elicit a wide array of adverse effects in almost every organ system. Among them, renal involvement is probably one of the most complex to identify.

CASE SUMMARY

We describe four cases of kidney damage caused by different IFN formulations: IFN-β-related thrombotic microangiopathy, IFN-β-induced systemic lupus erythematosus, and two cases of membranous nephropathy secondary to pegylated-IFN-α 2B. In each case, we carefully excluded any other possible cause of renal involvement. Once suspected as the casual relationship between drug and kidney damage, IFN treatment was immediately discontinued. In three cases, we observed a complete and persistent remission of clinical and laboratory abnormalities after IFN withdrawal, while the patient who developed thrombotic microangiopathy, despite IFN withdrawal and complement-inhibitor therapy with eculizumab, showed persistent severe renal failure requiring dialysis.

CONCLUSION

This case series highlights the causal relationship between IFN treatment and different types of renal involvement and enables us to delineate several peculiarities of this association.

APOL1-Associated Collapsing Focal Segmental Glomerulosclerosis in a Patient With Stimulator of Interferon Genes (STING)-Associated Vasculopathy With Onset in Infancy (SAVI)

Apolipoprotein L1 (APOL1) risk variants G1 and G2 are known to result in risk for kidney disease in patients of African ancestry. APOL1-associated nephropathy typically occurs in association with certain environmental factors or systemic diseases. As such, there has been increasing evidence of the role of interferon (IFN) pathways in the pathogenesis of APOL1-associated collapsing glomerulopathy in patients with human immunodeficiency virus (HIV) infection and systemic lupus erythematosus, 2 conditions that are associated with high IFN levels. Collapsing glomerulopathy has also been described in patients receiving exogenous IFN therapy administered for various medical conditions. We describe a patient with a genetic condition that results in an increased IFN state, stimulator of IFN genes (STING)-associated vasculopathy with onset in infancy (SAVI), who developed collapsing glomerulopathy during a flare of his disease. The patient was found to have APOL1 G1 and G2 risk variants. This case supports the role of IFN in inducing APOL1-associated collapsing glomerulopathy.

Acute kidney injury in the patient with cancer

Dramatic advances in the care of patients with cancer have led to significant improvement in outcomes and survival. However, renal manifestations of the underlying cancer as well as the effects of anti-neoplastic therapies leave patients with significant morbidity and chronic kidney disease risks. The most common renal manifestations associated with cancer include acute kidney injury (AKI) in the setting of multiple myeloma, tumor lysis syndrome, post-hematopoietic stem cell therapy, and AKI associated with chemotherapy. Knowledge of specific risk factors, modification of risk and careful attention to rapid AKI diagnosis are critical for improving outcomes.

Lupus Podocytopathy: An Overview

In systemic lupus erythematosus, nephrotic-range proteinuria typically signals the presence of a proliferative lupus nephritis (class III/IV) and/or membranous lupus nephritis (class V, with or without concomitant class III or IV lesions). However, in rare instances, systemic lupus erythematosus patients with nephrotic syndrome have kidney biopsy findings of normal glomeruli or focal segmental glomerulosclerosis lesions, with or without mesangial proliferation, on light microscopy; the absence of subepithelial or subendothelial deposits on immunofluorescence and electron microscopy; and diffuse foot process effacement on electron microscopy. This pattern, termed lupus podocytopathy, is a unique form of lupus nephritis that mimics minimal change disease or primary focal segmental glomerulosclerosis and represents approximately 1% of lupus nephritis biopsies. Here we review the clinical features, histological manifestations, diagnostic criteria and classification, pathogenesis, treatment, and prognosis of lupus podocytopathy.

APOL1 and kidney cell function

The apolipoprotein L1 (APOL1) gene is unique to humans and gorillas and appeared ~33 million years ago. Since the majority of the mammals do not carry APOL1, it seems to be dispensable for kidney function. APOL1 renal risk variants (RRVs; G1 and G2) are associated with the development as well as progression of chronic kidney diseases (CKDs) at higher rates in populations with African ancestry. Cellular expression of two APOL1 RRVs has been demonstrated to induce cytotoxicity, including necrosis, apoptosis, and pyroptosis, in several cell types including podocytes; mechanistically, these toxicities were attributed to lysosomal swelling, K⁺ depletion, mitochondrial dysfunction, autophagy blockade, protein kinase receptor activation, ubiquitin D degradation, and endoplasmic reticulum stress; notably, these effects were found to be dose dependent and occurred only in overtly APOL1 RRV-expressing cells. However, cellular protein expressions as well as circulating blood levels of APOL1 RRVs were not elevated in patients suffering from APOL1 RRV-associated CKDs. Therefore, the question arises as to whether it is gain or loss of function on the part of APOL1 RRVs contributing to kidney cell injury. The question seems to be more pertinent after the recognition of the role of APOL1 nonrisk (G0) in the transition of parietal epithelial cells and preservation of the podocyte molecular phenotype through modulation of the APOL1-miR-193a axis. With this background, the present review analyzed the available literature in terms of the known function of APOL1 nonrisk and how the loss of these functions could have contributed to two APOL1 RRV-associated CKDs.

Antisense oligonucleotide treatment ameliorates IFN-γ-induced proteinuria in APOL1-transgenic mice

African Americans develop end-stage renal disease at a higher rate compared with European Americans due to 2 polymorphisms (G1 and G2 risk variants) in the apolipoprotein L1 (APOL1) gene common in people of African ancestry. Although this compelling genetic evidence provides an exciting opportunity for personalized medicine in chronic kidney disease, drug discovery efforts have been greatly hindered by the fact that APOL1 expression is lacking in rodents. Here, we describe a potentially novel physiologically relevant genomic mouse model of APOL1-associated renal disease that expresses human APOL1 from the endogenous human promoter, resulting in expression in similar tissues and at similar relative levels as humans. While naive APOL1-transgenic mice did not exhibit a renal disease phenotype, administration of IFN-γ was sufficient to robustly induce proteinuria only in APOL1 G1 mice, despite inducing kidney APOL1 expression in both G0 and G1 mice, serving as a clinically relevant "second hit." Treatment of APOL1 G1 mice with IONIS-APOL1Rx, an antisense oligonucleotide (ASO) targeting APOL1 mRNA, prior to IFN-γ challenge robustly and dose-dependently inhibited kidney and liver APOL1 expression and protected against IFN-γ-induced proteinuria, indicating that the disease-relevant cell types are sensitive to ASO treatment. Therefore, IONIS-APOL1Rx may be an effective therapeutic for APOL1 nephropathies and warrants further development.

Collapsing glomerulopathy in older adults

Collapsing glomerulopathy has been described in settings of viral infections, drug, genetic, ischemic, renal transplant, and idiopathic conditions. It has a worse prognosis than other morphologic variants of focal segmental glomerulosclerosis, and may be treated with aggressive immunosuppression. In this study, we sought to characterize the clinical and morphologic findings in older adults with collapsing glomerulopathy. Renal biopsies and associated clinical data from patients aged 65 or older with a diagnosis of collapsing glomerulopathy were retrospectively reviewed at 3 academic institutions. Patients (n = 41, 61% male, median age 71) usually had hypertension (88%), nephrotic range proteinuria (91%), and renal insufficiency (median serum creatinine 2.5 mg/dL). A likely precipitating drug (5%) or vascular procedure (5%) was identified in a minority of cases; viral infections were infrequent. Renal biopsies contained a median of 40% globally and 16% segmentally sclerotic glomeruli. Approximately 60% of cases had moderate or severe arteriosclerosis, arteriolar hyalinosis, and/or tubular atrophy and interstitial fibrosis; 7% had atheroembolic disease and 5% had thrombotic microangiopathy. In 28 patients with available follow-up information, eight (19%) were treated with immunosuppressives, which were not tolerated by 2. At a median interval of 14 months, 5 (18%) patients had died, 12 (43%) had end stage renal disease, and 12 were alive with renal insufficiency and proteinuria. Treatment with immunosuppressive therapy did not have a significant benefit with regard to the primary outcome of overall or renal survival. One steroid-treated patient with diabetes died 6 weeks after biopsy, with invasive rhinoorbital Rhizopus infection. In conclusion, collapsing glomerulopathy in older patients is usually not associated with viral infections, and is accompanied by significant chronic injury in glomeruli, vasculature, and tubulointerstitium. Aggressive immunosuppression likely contributed to one death in a patient with diabetes, and did not yield an overall or renal survival advantage in this cohort.

Biological alterations in renal and hepatic tissues by a novel gold (III) anti-cancerous compound

Objective(s):

Newer organo-metallic, specifically gold (III) complexes with multiple ligands are currently being formulated with primary focus of having increased anti-cancerous properties and decreased cytotoxicity. In this study, histological toxicity profile of a newly formulated anti-cancerous gold (III) compound [trans-(±)-1,2-(DACH)₂Au]Cl₃ Bis(trans-1,2-Diaminocyclohexane) was investigated by evaluation of kidney and liver tissues of rats treated by the compound.

Materials and Methods:

This is a quasi-experimental study. In acute toxicity component of the study, (n = 16) male rats weighing between 200–250 g were administered single, variable concentration of the gold (III) compound, [trans-(±)-1,2-(DACH)₂Au]Cl₃ Bis(trans-1,2-Diaminocyclohexane) to determine LD₅₀ (dose that is lethal to 50% of rats). An IP injection of 2.3 mg/kg (equivalent to 1/10 of LD₅₀) was injected for 14 consecutive days to (n=10) male rats in the sub-acute component of the study. Autopsy preservation of liver and kidney tissue in buffered formalin, sample processing, histopathological evaluation, and comparison with unremarkable controls (n=5) was conducted sequentially.

Results:

A dose of 2.3 mg/kg did not produce any tubular necrosis in kidney specimens. Mild interstitial inflammation with prominence of plasma cells was the main histological alteration. Plasmacytic pyelitis was also seen. Varying extents of cytoplasmic vacuolization and mild focal lobular and portal inflammation were predominant hepatic microscopic findings.

Conclusion:

[trans-(±)-1,2-(DACH)₂Au]Cl₃ Bis(trans-1,2-Diaminocyclohexane) produced no histological damage in renal and hepatic tissues of rats. This very limited sample animal-based study points to the relative safety of this new gold compound. However, there is a need to compare this compound with established drugs in a comparative non-animal based study.

Collapsing glomerulopathy: update

Collapsing glomerulopathy (CG) is a rare entity as a glomerular disease. Although it has been considered as a variant of focal segmental glomerulosclerosis, the fact is that the podocyte lesions show different features with respect to the typical focal segmental glomerulosclerosis, an aspect that has been attributed to a type of podocytopathy. In CG, the podocyte lesion is typically characterised by a dysregulated podocyte phenotype, reflected by the loss of expression of mature podocyte markers. CG can be a primary disease or it can be associated with several causal factors that develop a common histopathological entity. The clinical expressiveness of CG is often characterised by the presence of a nephrotic syndrome and a rapid deterioration of the renal function than other variants of the focal segmental glomerulosclerosis. The prognosis of these patients is a rapid progression towards end-stage renal disease with poor response to treatment.

Collapsing glomerulonephritis with podocyte markers in hemophagocytic syndrome secondary to hepatosplenic T-cell lymphoma

The hemophagocytic syndrome is a serious clinical-histological entity secondary to different diseases. Collapsing glomerulonephritis is a proliferative podocytopathy that usually has an unfavorable renal prognosis. We present a case in which both entities were associated, which is an infrequent form of hepatosplenic T-cell lymphoma. In addition, we review the role of the markers of podocyte dedifferentiation in this glomerulopathy and its pathophysiology and treatment.

The adverse kidney effects of cancer immunotherapies

Cancer therapies are a common cause of acute and chronic kidney disease, which are increasingly being seen by nephrologists in clinical practice. Conventional chemotherapeutic drugs and novel targeted agents are effective cancer therapies but their use is complicated by nephrotoxicity. Cancer immunotherapies exploit various properties of immune cells to enhance immune-mediated tumor killing. Interferon and high-dose interleukin-2 are older immunotherapies first employed clinically in the 1980s and 1990s to treat a number of different cancers. While effective, these two therapies have well-known systemic toxicities, which include acute kidney disease. The emergence of the new cancer immunotherapies over the past decade brings more effective treatment options. The immune checkpoint inhibitors and chimeric antigen receptor T cells are exciting additions to the cancer treatment armamentarium. These agents effectively treat a several and a growing list of cancers that have otherwise failed other therapies. However, as with the conventional and targeted cancer agents, drug-induced acute and chronic kidney disease is an untoward effect of this group of drugs. We will undertake a case-based review: the newer immunotherapies followed by the older therapies, interferon and interleukin-2.

APOL1 polymorphisms and kidney disease: loss-of-function or gain-of-function?

The mechanism that explains the association of APOL1 variants with nondiabetic kidney diseases in African Americans remains unclear. Kidney disease risk is inherited as a recessive trait, and many studies investigating the intracellular function of APOL1 have indicated the APOL1 variants G1 and G2 are associated with cytotoxicity. Whether cytotoxicity results from the absence of a protective effect conferred by the G0 allele or is induced by a deleterious effect of variant allele expression has not be conclusively established. A central issue hampering basic biology studies is the lack of model systems that authentically replicate APOL1 expression patterns. APOL1 is present in humans and a few other primates and appears to have important functions in the kidney, as the kidney is the primary target for disease associated with the genetic variance. There have been no studies to date assessing the function of untagged APOL1 protein under native expression in human or primate kidney cells, and no studies have examined the heterozygous state, a disease-free condition in humans. A second major issue is the chronic kidney disease (CKD)-associated APOL1 variants are conditional mutations, where the disease-inducing function is only evident under the appropriate environmental stimulus. In addition, it is possible there may be more than one mechanism of pathogenesis that is dependent on the nature of the stressor or other genetic variabilities. Studies addressing the function of APOL1 and how the CKD-associated APOL1 variants cause kidney disease are challenging and remain to be fully investigated under conditions that faithfully model known human genetics and physiology.

Donor APOL1 high-risk genotypes are associated with increased risk and inferior prognosis of de novo collapsing glomerulopathy in renal allografts

Collapsing focal segmental glomerulosclerosis (cFSGS) in the native kidney is associated with heavy proteinuria and accelerated renal failure. However, cFSGS in the renal allograft is less well characterized. Here we report clinico-pathologic features and APOL1 donor risk genotypes in 38 patients with de novo post-kidney transplant cFSGS. Recipients were 34% female and 26% African American. Concurrent viral infections and acute vaso-occlusion (including thrombotic microangiopathy, cortical necrosis, atheroembolization, and cardiac arrest with contralateral graft thrombosis) were present in 13% and 29% of recipients, respectively. Notably, 61% of patients had concurrent acute rejection and 47% received grafts from African American donors, of which 53% carried APOL1 high-risk genotypes. These frequencies of acute rejection and grafts from African American donors were significantly higher than in our general transplant population (35% and 16%, respectively). Patients had a median serum creatinine of 5.4 mg/dl, urine protein/creatinine 3.5 g/g, and 18% had nephrotic syndrome. Graft failure occurred in 63% of patients at an average of eighteen months post-index biopsy. By univariate analysis, donor APOL1 high-risk genotypes, post-transplant time, nephrotic syndrome, and chronic histologic changes were associated with inferior graft survival while acute vaso-occlusion was associated with superior graft survival. Donor APOL1 high-risk genotypes independently predicted poor outcome. Compared to native kidney cFSGS, post-transplant cFSGS had more acute vaso-occlusion but less proteinuria. Thus, de novo cFSGS is associated with variable proteinuria and poor prognosis with potential predisposing factors of African American donor, acute rejection, viral infection and acute vaso-occlusion. Additionally, donor APOL1 high-risk genotypes are associated with higher incidence and worse graft survival.

Drug-induced Glomerulonephritis: The Spectre of Biotherapeutic and Antisense Oligonucleotide Immune Activation in the Kidney

Prevalence of immune-mediated glomerulonephritis has increased in preclinical toxicity studies, with more frequent use of biotherapeutic agents (especially antigenic humanized molecules) and antisense oligonucleotide (ASO) therapies. Immune complex disease affects a small number of study monkeys, often correlates with antidrug antibody (ADA) titers, and occurs at a dose that favors immune complex formation or impedes clearance. While preclinical glomerulonephritis often fails to correlate with evidence of glomerular or vascular injury in human clinical trials and is not considered predictive, additional animal investigative immunohistochemical work may be performed to substantiate evidence for immune complex pathogenesis. While ADA is most commonly encountered as a predisposing factor with biotherapeutic agents, complement activation may occur without circulating complexes, and other mechanisms of non-ADA immune-mediated glomerulonephritis have been observed including nonendogenous immune aggregates and immunoregulatory pharmacology. Although glomerulonephritis associated with oligonucleotide therapies has been noted occasionally in preclinical studies and more rarely with human patients, pathophysiologic mechanisms involved appear to be different between species and preclinical cases are not considered predictive for humans. ADA is not involved in oligonucleotide-associated cases, and complement fixation plays a more important role in monkeys. Recent screening of ASOs for proinflammatory activity appears to have decreased glomerulonephritis incidence preclinically.

Nephrotoxicity of Cancer Immunotherapies: Past, Present and Future

Nephrotoxicity from cancer therapies is common and increasingly encountered in clinical practice, such that the subfield of "onco-nephrology" has emerged. Conventional chemotherapeutic drugs and novel agents targeting specific genes/proteins are effective cancer therapies but suffer from a number of adverse kidney effects. An effective avenue of cancer treatment is immunotherapy, which uses drugs that augment immune system-mediated recognition and targeting of tumor cells. As such, leveraging the immune system to target malignant cells represents an important modality in eradicating cancer. IFN and high-dose IL-2 are older immunotherapies used in clinical practice to treat various malignancies, whereas new cancer immunotherapies have emerged over the past decade that offer even more effective treatment options. The immune checkpoint inhibitors are an exciting addition to the cancer immunotherapy armamentarium. Chimeric antigen receptor T cells are also a new immunotherapy used to treat various hematologic malignancies. However, as with the conventional and targeted cancer agents, the immunotherapies are also associated with immune-related adverse effects, which includes nephrotoxicity.

Acute kidney injury and electrolyte disorders in the critically ill patient with cancer

PURPOSE OF REVIEW

Patients with cancer increasingly make up a significant proportion of patients receiving care in the intensive care unit (ICU). Acute kidney injury and cancer-associated electrolyte disorders are encountered in many of these patients and can significantly impact both short-term and long-term outcomes.

RECENT FINDINGS

Advances in chemotherapeutic regimens as well as in our understanding of cancer-associated kidney disease highlight the need for specialized knowledge of the unique causes and therapies required in this subset of critically ill patients. This is especially the case as targeted cancer therapies may have off-target effects that need to be recognized in a timely manner.

SUMMARY

This review outlines key knowledge areas for critical care physicians and nephrologists caring for patients with cancer and associated kidney issues such as acute kidney injury and electrolyte disorders. Specifically, understanding kidney-specific effects of new chemotherapeutic approaches is outlined, and provides an up-to-date compendium of these effects.

APOL1: The Balance Imposed by Infection, Selection, and Kidney Disease

Chronic kidney disease (CKD) affects millions of people and constitutes a major health and financial burden worldwide. People of African descent are at an increased risk of developing kidney disease, which is mostly explained by two variants in the Apolipoprotein L1 (APOL1) gene that are found only in people of west African origin. It is hypothesized that these variants were genetically selected due to the protection they afford against African sleeping sickness, caused by the parasite Trypanosoma brucei. Targeting mutant APOL1 could have substantial therapeutic potential for treating kidney disease. In this review, we will describe the intriguing interplay between microbiology, genetics, and kidney disease as revealed in APOL1-associated kidney disease, discuss APOL1-induced cytotoxicity and its therapeutic implications.

Renal failure during chemotherapy: renal biopsy for assessing subacute nephrotoxicity of pemetrexed

BACKGROUND

Pemetrexed, a multitargeted antifolate cytotoxic agent, is currently used primarily in combination with cisplatin for metastatic non-small cell lung cancer and for malignant mesothelioma. Acute renal toxicity of pemetrexed has been recently described with polychemotherapy, in which the individual responsibility of each drug is difficult to establish. Only one recent report documents renal involvement in long-term exposed patients.

CASE PRESENTATION

We report on a case of rapidly progressive nephropathy leading to the cessation of platinum salts and the secondary interruption of pemetrexed and bevacizumab. Acute tubular necrosis shown on the renal biopsy could potentially be due to pemetrexed. Persistent severe renal failure after the resumption of all drugs led to new treatment lines with gemcitabine (while the glomerular filtration rate was below 30 ml/min/1.73m2), then followed by Taxol.

CONCLUSIONS

The optimal strategy with regard to renal complications in cancer patients is not clear. Acute or chronic loss in renal function generally leads to a new treatment line, possibly impairing the overall success of the treatment. The use of chemotherapy in patients with a glomerular filtration rate below 30 ml/min/1.73m2 is usually associated with an increased risk of side effects when not contraindicated by renal elimination of the drug.

Tubuloreticular Inclusions in the Absence of Systemic Lupus Erythematosus and HIV Infection: A Report of Three Pediatric Cases

Tubuloreticular inclusions (TRIs) are subcellular structures located within the cisternae of endoplasmic reticulum. Formation of TRIs has been linked to the exposure of excess interferon (IFN), either from endogenous or exogenous sources. In renal disease, TRIs have been most commonly associated with systemic lupus erythematosus (SLE), and human immunodeficiency virus-associated nephropathy (HIVAN). Case reports of patients with renal biopsies showing TRIs without underlying SLE or HIV are infrequent in adults, and to our knowledge none have been reported in children. We report 3 pediatric cases in which the renal biopsy showed TRIs on electron microscopy without underlying SLE or HIV infection. The first patient presented at 2 years of age with nephrotic syndrome and renal failure. His renal biopsy revealed focal segmental glomerulosclerosis and TRIs. The second patient presented at 6 months of age with infantile nephrotic syndrome, and his renal biopsy revealed membranous glomerulopathy and TRIs. The last patient presented at 4 years of age with acute kidney injury of unclear etiology leading to chronic kidney disease. Her biopsy revealed acute and chronic tubulointerstitial nephritis with TRIs. Despite extensive evaluation in all 3 patients, including testing for HIV infection and SLE, we could not identify an underlying etiology to explain the presence of TRIs. In conclusion, renal biopsy with TRIs in the absence of underling SLE and HIV remains obscure. We propose a possible role for excess IFN triggered by an abnormal immune response to common viral infections in the formation of TRIs and renal injury.

Re-Examining Neutrophil Participation in GN

Significant advances in understanding the pathogenesis of GN have occurred in recent decades. Among those advances is the finding that both innate and adaptive immune cells contribute to the development of GN. Neutrophils were recognized as key contributors in early animal models of GN, at a time when the prevailing view considered neutrophils to function as nonspecific effector cells that die quickly after performing antimicrobial functions. However, advances over the past two decades have shown that neutrophil functions are more complex and sophisticated. Specifically, research has revealed that neutrophil survival is regulated by the inflammatory milieu and that neutrophils demonstrate plasticity, mediate microbial killing through previously unrecognized mechanisms, demonstrate transcriptional activity leading to the release of cytokines and chemokines, interact with and regulate cells of the innate and adaptive immune systems, and contribute to the resolution of inflammation. Therefore, neutrophil participation in glomerular diseases deserves re-evaluation. In this review, we describe advances in understanding classic neutrophil functions, review the expanded roles of neutrophils in innate and adaptive immune responses, and summarize current knowledge of neutrophil contributions to GN.

Collapsing glomerulopathy: a 30-year perspective and single, large center experience

Collapsing glomerulopathy (CGP) is a pattern of kidney injury seen on renal biopsy with multiple associations and etiologies. It is most commonly described in African-Americans and others with recent African ancestry. The disease is rapidly progressive and often presents with abrupt onset of renal failure and nephrotic-range proteinuria. Since its description 30 years ago, this entity has transformed from a morphologic diagnosis typically seen in the setting of HIV infection to a complicated diagnosis with numerous etiologies, many of which are associated with underlying apolipoprotein L1 (APOL1)-risk variants or other genetic disorders. We review the evolution of CGP, and its history and proposed pathomechanisms. We also present the disease spectrum from our experience with emphasis on recognizing the lesion, distinguishing from mimics and linking the histopathological pattern to a specific cause. Our understanding continues to evolve as clinicians and scientists work toward a more complete understanding of the molecular pathways of injury in this disease and how these might be disrupted for therapeutic purposes. Much still remains to be discovered in CGP as the molecular underpinnings leading to disease are still not completely understood and no effective treatment exists despite the high morbidity. Based on this rapid evolution, CGP is a modern template of how we diagnose and think about kidney disease. The story of CGP represents the current shift in nephrology and nephropathology from morphology-alone-based diagnosis to a comprehensive approach including molecular diagnostics. We believe this new, holistic approach will lead to pathogenesis-centered diagnoses that will help to individualize risk stratification and treatment protocols.

HIV associated kidney diseases: Clarifying concordance between renal failure in HIV infection and histopathologic manifestations at kidney biopsy

Patients with HIV infection have a wide spectrum of renal diseases. Some are known to be the direct effect of the viral infection while others are renal diseases that also occur in uninfected populations. HIV associated nephropathy (HIVAN) is considered to be a subtype of primary focal and segmental glomerulosclerosis that is distinct in HIV infected patients. It is more frequent in the African-American population and associated with mutations of the apolipoprotein L1 (APOL1) gene. HIV associated immune complex kidney disease (HIVICD) encompasses a spectrum of HIV associated renal diseases characterized by the presence of immune complex deposition within glomeruli. Thrombotic microangiopathy (TMA) is a complication of HIV infection that presents with hemolytic anemia, thrombocytopenia, and renal failure. TMA in HIV patients is associated with very high mortality. Lastly, the multitude of antiretroviral drugs used for treatment of HIV infections can result in nephrotoxicity. Although a kidney biopsy may not be the first line study for renal disease, knowledge of the different histopathologic features of HIV-associated and unassociated diseases is of paramount importance in the treatment and subsequent outcome of renal function in HIV infected patients. In this review we will describe the histopathologic features and discuss the pathophysiology of the entities previously named.

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.

Anticancer Drug-Induced Acute Kidney Injury

Acute kidney injury (AKI) is a growing problem with untoward economic and medical consequences. Anticancer drug toxicity remains an important and increasing cause of AKI. Importantly, drug-induced AKI affects all nephron segments—vasculature, glomerulus, tubules, and interstitium. Recent studies have increased insight into the subcellular mechanisms of drug-induced AKI that include direct cellular toxicity and immune-mediated effects. Identification of patients with high-risk cancer before drug exposure may allow prevention or at least a reduction in the development and severity of nephrotoxicity. Recognition of drug-induced AKI and rapid discontinuation (or dose reduction) of the offending agents, when appropriate, are critical to maximizing kidney function recovery. Preventive measures require understanding patient and drug-related risk factors coupled with correcting risk factors, assessing baseline kidney function before initiation of therapy, adjusting the drug dosage and avoiding use of nephrotoxic drug combinations.

Interferon Induced Focal Segmental Glomerulosclerosis

Behçet's disease is an inflammatory disease of unknown etiology which involves recurring oral and genital aphthous ulcers and ocular lesions as well as articular, vascular, and nervous system involvement. Focal segmental glomerulosclerosis (FSGS) is usually seen in viral infections, immune deficiency syndrome, sickle cell anemia, and hyperfiltration and secondary to interferon therapy. Here, we present a case of FSGS identified with kidney biopsy in a patient who had been diagnosed with Behçet's disease and received interferon-alpha treatment for uveitis and presented with acute renal failure and nephrotic syndrome associated with interferon.

Pathogenesis of Focal Segmental Glomerulosclerosis

Focal segmental glomerulosclerosis (FSGS) is characterized by focal and segmental obliteration of glomerular capillary tufts with increased matrix. FSGS is classified as collapsing, tip, cellular, perihilar and not otherwise specified variants according to the location and character of the sclerotic lesion. Primary or idiopathic FSGS is considered to be related to podocyte injury, and the pathogenesis of podocyte injury has been actively investigated. Several circulating factors affecting podocyte permeability barrier have been proposed, but not proven to cause FSGS. FSGS may also be caused by genetic alterations. These genes are mainly those regulating slit diaphragm structure, actin cytoskeleton of podocytes, and foot process structure. The mode of inheritance and age of onset are different according to the gene involved. Recently, the role of parietal epithelial cells (PECs) has been highlighted. Podocytes and PECs have common mesenchymal progenitors, therefore, PECs could be a source of podocyte repopulation after podocyte injury. Activated PECs migrate along adhesion to the glomerular tuft and may also contribute to the progression of sclerosis. Markers of activated PECs, including CD44, could be used to distinguish FSGS from minimal change disease. The pathogenesis of FSGS is very complex; however, understanding basic mechanisms of podocyte injury is important not only for basic research, but also for daily diagnostic pathology practice.

Refinement of the HIVAN1 Susceptibility Locus on Chr. 3A1-A3 via Generation of Sub-Congenic Strains

HIV-1 transgenic mice on the FVB/NJ background (TgFVB) represent a validated model of HIV-associated nephropathy (HIVAN). A major susceptibility locus, HIVAN1, was previously mapped to chromosome 3A1-A3 in a cross between TgFVB and CAST/EiJ (CAST) strains, and introgression of a 51.9 Mb segment encompassing HIVAN1 from CAST into TgFVB resulted in accelerated development of nephropathy. We generated three sub-congenic strains carrying CAST alleles in the proximal or distal regions of the HIVAN1 locus (Sub-II, 3.02–38.93 Mb; Sub-III, 38.45–55.1 Mb and Sub-IV, 47.7–55.1 Mb, build 38). At 5–10 weeks of age, histologic injury and proteinuria did not differ between HIV-1 transgenic Sub-II and TgFVB mice. In contrast, HIV-1 transgenic Sub-III and Sub-IV mice displayed up to 4.4 fold more histopathologic injury and 6-fold more albuminuria compared to TgFVB mice, similar in severity to the full-length congenic mice. The Sub-IV segment defines a maximal 7.4 Mb interval for HIVAN1, and encodes 31 protein coding genes: 15 genes have missense variants differentiating CAST from FVB, and 14 genes show differential renal expression. Of these, Frem1, Foxo1, and Setd7 have been implicated in the pathogenesis of nephropathy. HIVAN1 congenic kidneys are histologically normal without the HIV-1 transgene, yet their global transcriptome is enriched for molecular signatures of apoptosis, adenoviral infection, as well as genes repressed by histone H3 lysine 27 trimethylation, a histone modification associated with HIV-1 life cycle. These data refine HIVAN1to 7.4 Mb and identify latent molecular derangements that may predispose to nephropathy upon exposure to HIV-1.

Collapsing glomerulopathy in a young woman with APOL1 risk alleles following acute parvovirus B19 infection: a case report investigation

BACKGROUND

Collapsing Glomerulopathy (CG), also known as the collapsing variant of Focal Segmental Glomerulosclerosis (FSGS), is distinct in both its clinical severity and its pathophysiologic characteristics from other forms of FSGS. This lesion occurs disproportionally in patients carrying two APOL1 risk alleles, and is the classic histologic lesion resulting from Human Immunodeficiency Virus (HIV) infection of podocytes. Other viral infections, including parvovirus B19, and drugs such as interferon that perturb the immune system, have also been associated with CG. Despite significant advances, explaining such genetic and immune/infectious associations with causative mechanisms and supporting evidence has proven challenging.

CASE PRESENTATION

We report the case of a healthy (HIV-negative) pregnant 36 year-old Caribbean-American woman who presented with nephrotic syndrome and fetal demise in the setting of acute parvovirus B19 infection. A series of three renal biopsies and rapid clinical course showed progression from significant podocyte injury with mild light microscopy findings to classic viral-associated CG to ESRD in less than 3 months. Genetic analysis revealed two APOL1 G1 risk alleles.

CONCLUSIONS

This is the first published case report of CG in the setting of acute parvovirus infection in a patient with two APOL1 risk allelles, and parvoviral proteins identified in renal epithelium on kidney biopsy. These findings support the causative role of parvovirus B19 infection in the development of CG on the background of APOL1 genetic risk.

Antineoplastic Treatment and Renal Injury: An Update on Renal Pathology Due to Cytotoxic and Targeted Therapies

Cancer patients experience kidney injury from multiple sources, including the tumor itself, diagnostic procedures, hypovolemia, infection, and drug exposure, superimposed upon baseline chronic damage. This review will focus on cytotoxic or targeted chemotherapy-associated renal injury. In this setting, tubulointerstitial injury and thrombotic microangiopathy (vascular injury) are more common than other forms of kidney injury including glomerular. Cisplatin, pemetrexed, and ifosfamide are well-known causes of acute tubular injury/necrosis. Acute interstitial nephritis seems underrecognized in this clinical setting. Interstitial nephritis is emerging as an "immune-related adverse effect" (irAE's) with immune checkpoint inhibitors in small numbers of patients. Acute kidney injury is rarely reported with targeted therapies such as BRAF inhibitors (vemurafinib, dabrafenib), ALK inhibitors (crizotinib), and mTOR inhibitors (everolimus, temsirolimus), but additional biopsy data are needed. Tyrosine kinase inhibitors and monoclonal antibodies that block the vascular endothelial growth factor pathway are most commonly associated with thrombotic microangiopathy. Other causes of thrombotic microangiopathy in the cancer patients include cytotoxic chemotherapies such as gemcitabine and mitomycin C, hematopoietic stem cell transplant, and cancer itself (usually high-stage adenocarcinoma with marrow and vascular invasion). Cancer patients are historically underbiopsied, but biopsy can reveal type, acuity, and chronicity of renal injury, and facilitate decisions concerning continuation of chemotherapy and/or initiation of renoprotective therapy. Biopsy may also reveal unrelated and unanticipated findings in need of treatment.

Efficacy and Safety of Direct Acting Antivirals in Kidney Transplant Recipients with Chronic Hepatitis C Virus Infection

The prevalence of Hepatitis C Virus (HCV) infection is significantly higher in patients with end-stage renal disease compared to the general population and poses important clinical challenges in patients who undergo kidney transplantation. Historically, interferon-based treatment options have been limited by low rates of efficacy and significant side effects, including risk of precipitating rejection. Limited data exist on the use of all-oral, interferon-free direct-acting antiviral (DAA) therapies in kidney transplant recipients. In this study, we performed a retrospective chart review with prospective clinical follow-up of post-kidney transplant patients treated with DAA therapies at three major hospitals in Boston, MA. A total of 24 kidney recipients with HCV infection received all-oral DAA therapy post-transplant. Patients were predominantly male (79%) with a median age of 60 years (range 34–70 years), median creatinine of 1.2 mg/dL (0.66–1.76), and 42% had advanced fibrosis or cirrhosis. The majority had HCV genotype 1a infection (58%). All patients received full-dose sofosbuvir; it was paired with simeprevir (9 patients without and 3 patients with ribavirin), ledipasvir (7 patients without and 1 patient with ribavirin) or ribavirin alone (4 patients). The overall sustained virologic response (SVR12) was 91% (21 out of 23 patients). One patient achieved SVR4 but demised prior to SVR12 check point due to treatment unrelated cause. Two treatment failures were successfully retreated with alternative DAA regimens and achieved SVR. Both initials failures occurred in patients with advanced fibrosis or cirrhosis, with genotype 1a infection, and prior HCV treatment failure. Adverse events were reported in 11 patients (46%) and were managed clinically without discontinuation of therapy. Calcineurin inhibitor trough levels did not significantly change during therapy. In this multi-center series of patients, all-oral DAA therapy appears to be safe and effective in post-kidney transplant patients with chronic HCV infection.

Interferon β associated nephropathy in a Multiple Sclerosis patient: A case and review

BACKGROUND

Interferon beta (IFN β) subtypes are largely used as immunomodulatory agents in Multiple Sclerosis (MS) treatment. While being generally well tolerated, they can cause various side effects. Adverse effects related to kidney are rarely reported.

CASE REPORT

We report a 32 years old male patient who developed nephrotic syndrome while receiving IFN β for MS. Biopsy showed focal segmental glomerulosclerosis. He went into remisson after cessation of drug and with the aid of angiotensin II antagonists. Here, we report this case and a review of similar cases reported in literature.

CONCLUSIONS

Although it's a rare adverse effect and tend to show good prognosis physicians should pay careful attention to symptoms and findings of nephropathy during follow ups of patients under treatment with these agents.