Membranoproliferative glomerulonephritis associated with hepatitis C virus infection

HEV ORF2 protein-antibody complex deposits are associated with glomerulonephritis in hepatitis E with reduced immune status

Hepatitis E virus (HEV) infection, one of the most common forms of hepatitis worldwide, is often associated with extrahepatic, particularly renal, manifestations. However, the underlying mechanisms are incompletely understood. Here, we report the development of a de novo immune complex-mediated glomerulonephritis (GN) in a kidney transplant recipient with chronic hepatitis E. Applying immunostaining, electron microscopy, and mass spectrometry after laser-capture microdissection, we show that GN develops in parallel with increasing glomerular deposition of a non-infectious, genome-free and non-glycosylated HEV open reading frame 2 (ORF2) capsid protein. No productive HEV infection of kidney cells is detected. Patients with acute hepatitis E display similar but less pronounced deposits. Our results establish a link between the production of HEV ORF2 protein and the development of hepatitis E-associated GN in the immunocompromised state. The formation of glomerular IgG-HEV ORF2 immune complexes discovered here provides a potential mechanistic explanation of how the hepatotropic HEV can cause variable renal manifestations. These findings directly provide a tool for etiology-based diagnosis of hepatitis E-associated GN as a distinct entity and suggest therapeutic implications.

Renal Manifestations of Chronic Hepatitis C: A Review

Hepatitis C virus (HCV) has emerged as a major global health concern and, if left untreated, can lead to significant liver damage, including cirrhosis, decompensated liver disease, and hepatocellular carcinoma (HCC). Approximately 40% of patients with HCV infection experience extrahepatic manifestations, including renal involvement. HCV-related renal disease is of significant importance among patients with chronic kidney disease (CKD), leading to higher morbidity and mortality. The renal damage due to HCV infection primarily results from cryoglobulinemia and glomerulonephritis, with conditions such as membranoproliferative glomerulonephritis (MPGN) and membranous nephropathy (MN) being most prevalent. Despite advancements in treatment, including the use of directly acting antiviral agents (DAAs), renal complications remain a significant burden in untreated patients. HCV-positive patients on hemodialysis (HD) or those who have undergone kidney transplantation face increased mortality rates compared to their HCV-negative counterparts. Managing HCV infection before kidney transplantation is crucial to mitigate the risk of HCV-related renal complications. Conversely, kidney transplantation from HCV-infected donors is well established, as post-transplant treatment for HCV is safe and effective, potentially reducing mortality and morbidity for patients on transplant waiting lists. This review aims to provide a comprehensive analysis of the renal manifestations of HCV, emphasizing the importance of early diagnosis and treatment to improve patient outcomes.

Hepatitis C virus infection is associated with proteinuria according to a systematic review with meta-analysis

INTRODUCTION AND AIM

Hepatitis C virus infection and chronic kidney disease are major public health issues all over the world. It has been suggested a role of HCV as a risk factor for the development and progression of chronic kidney disease (defined by reduced glomerular filtration rate and/or detectable proteinuria) in the general population but conflicting findings have been given.

MATERIAL AND METHODS

A systematic review of the published medical literature was conducted to assess whether positive HCV serologic status is associated with greater rate of proteinuria in the adult general population. We used a random-effect model to generate a summary estimate of the relative risk of proteinuria with HCV across the published studies.

RESULTS

We identified 23 studies (n=198,967 unique patients) and performed separate meta-analyses according to the study design. Overall effect estimate was significant in cross-sectional (OR, 1.47, 95%CI, 1.3; 1.66) (P<0.001) and obvious between-study heterogeneity was observed (Q value by Chi-squared [χ2] test 27.3, P=0.02). The risk of proteinuria after exposure to HCV was also consistent among longitudinal studies (HR, 1.79, 95% CI, 1.17; 2.74) (P<0.001) and between-study heterogeneity occurred (Q value, 27.82 by X2 test, P=0.0001). Stratified analysis did not report heterogeneity in several comparisons-pooling studies based on urine protein/creatinine ratio (UACR) showed that the adjusted OR with HCV was 1.64 (95% CI, 1.41; 1.91, P<0.001) without heterogeneity (Q value by Chi-squared [χ2] test 9.98, P=NS). Meta-regression recorded a link between greater prevalence of proteinuria in males with HCV exposure (P=0.03). Studies based on univariate analysis (n=6, n=72, 551 unique patients) gave similar results, pooled OR 1.54 (95% CI, 1.08; 2.19) (P=0.0001).

CONCLUSIONS

An important relationship between HCV infection and higher risk of proteinuria in the general population exists. Research aimed to understand the biological mechanisms underlying such association is under way. We encourage to screen all patients with HCV exposure for proteinuria.

Understanding the relationship between HCV infection and progression of kidney disease

Hepatitis C virus (HCV) can cause a range of kidney diseases. HCV is the primary cause of mixed cryoglobulinaemia, which leads to cryoglobulinaemic vasculitis and cryoglobulinaemic glomerulonephritis (GN). Patients with acute cryoglobulinaemic vasculitis often exhibit acute kidney disease due to HCV infection, which typically progresses to acute kidney injury (AKI). HCV also increases the risk of chronic kidney disease (CKD) and the likelihood of developing end-stage renal disease (ESRD). Currently, direct-acting antiviral agents (DAAs) can be used to treat kidney disease at different stages. This review focuses on key findings regarding HCV and kidney disease, discusses the impact of DAAs, and highlights the need for further research and treatment.

Membranoproliferative Glomerulonephritis Pattern of Injury

Membranoproliferative glomerulonephritis (MPGN) is no longer a disease but a pattern of injury in various diseases. Characterized by electron-dense deposits, mesangial proliferation, and duplication of the glomerular basement membrane, MPGN was previously classified by findings seen by electron microscopy. However, recognizing complement dysfunction in relation to cases with the MPGN pattern of injury substantially changed our view of its pathogenesis. A new classification, including immune complex-mediated and complement-mediated MPGN, has become preferable and has been adopted by international guidelines. Despite these advancements, accurate diagnosis of MPGN remains a clinical challenge, given the pathological and clinical similarities between immune complex-mediated and complement-mediated MPGN. Additional testing, such as molecular and genetic testing, is often necessary. Here, we will summarize our current understanding of the MPGN pattern of injury from a pathology perspective as an introductory article in the following chapters.

Extrahepatic manifestations of HCV where do we stand?

Hepatitis C virus (HCV) infection has been associated as up 40-70% of patients with extrahepatic manifestations (EHM) and 36 different syndromes. These could be attributed to the fact that HCV is lymphotropic, particularly B lymphotropic, and not merely hepatotropic, and could trigger immunological alterations indirectly by exerting a chronic stimulus on the immune system with production of immunoglobulins having rheumatoid activity forming immune complexes and production of cryoglobulins. Cryoglobulinemoa plays a pivotal role in producing most EHM of HCV such as vasculitis, glomerulonephritis, arthritis and neuropathies. Less frequently; while less frequently, the direct viral cytopathic effect could lead to EHMs independent of cryoglobulinemia. The mainstay of treatment of EMH has been antivirals, since interferon era to direct-acting drugs era, with no differences between the two eras, despite the better virological response. Longer evaluation of virological response and clinical investigation with longer follow-ups are necessary.

Hepatitis C virus antibody seropositivity is associated with albuminuria but not peripheral artery disease in patients with type 2 diabetes

Hepatitis C virus (HCV) infection is prevalent in patients with type 2 diabetes mellitus (DM). We aimed to investigate whether HCV antibody (Ab) seropositivity is associated with diabetic micro- and macro-vascular diseases. In this hospital-based cross-sectional study, we retrospectively collected data from patients who participated in the diabetes pay-for-performance program and underwent HCV Ab screening in the annual comprehensive assessment between January 2021 and March 2022. We examined the relationships of HCV Ab seropositivity with the spot urinary albumin-to-creatinine ratio (UACR) and ankle-brachial index (ABI) in patients aged ≥ 50 years with type 2 DM. A total of 1758 patients were enrolled, and 85 (4.83%) of the enrolled patients had HCV Ab seropositivity. Multivariable regression analyses revealed that albuminuria showed a dose-dependent association with HCV Ab seropositivity (UACR [30-299 mg/g]: odds ratio [OR] = 1.463, 95% confidence interval [CI] 0.872‒2.456); UACR [≥ 300 mg/g]: OR = 2.300, 95% CI 1.160‒4.562; P for trend = 0.015) when compared with normal albuminuria (UACR < 30 mg/g). However, the proportion of patients with peripheral arterial disease, defined as an ABI ≤ 0.9, was not significantly different between the groups with and without HCV Ab seropositivity (3.5% vs. 3.9%, P = 0.999). In conclusion, severely increased albuminuria, but not the ABI, showed a significant association with HCV Ab seropositivity in patients aged ≥ 50 years with type 2 DM.

Therapeutic Potential of Rituximab in Managing Hepatitis C-Associated Cryoglobulinemic Vasculitis: A Systematic Review

(1) Background. Hepatitis C infection often leads to extrahepatic manifestations, including cryoglobulinemic vasculitis. This systematic review aimed to assess the efficacy and safety of rituximab in treating hepatitis C-associated cryoglobulinemic vasculitis. (2) Methods. Following PRISMA guidelines, databases were searched for relevant studies. Eligibility criteria included studies on hepatitis C-associated cryoglobulinemic vasculitis treated with rituximab. (3) Results. Nine studies met the eligibility criteria and were included in this analysis. Rituximab was commonly administered at 375 mg/m2 weekly for one month. The results consistently demonstrated the efficacy of rituximab, whether as a standalone treatment or as part of a therapeutic regimen. The combination of rituximab with Peg-IFN-α and ribavirin significantly increased the complete response rate compared to Peg-IFN-α and ribavirin alone (54.5% vs. 33.3%, p < 0.05). The 3-year sustained response rate was notably higher in the rituximab combination group (83.3% vs. 40%). In another trial, rituximab achieved remission in 83.3% of patients at 6 months, compared to only 8.3% in the control group. The efficacy of rituximab was supported by long-term experience, with clinical benefits in patients with severe cryoglobulinemic vasculitis, including those resistant to standard therapies. Mild adverse events were generally reported, with rare severe reactions in some studies. (4) Conclusions: In conclusion, rituximab appeared to be effective and safe in managing hepatitis C-associated cryoglobulinemic vasculitis, either alone or with antiviral therapy.

Treating Hepatitis C Prior to Total Hip Arthroplasty is Cost Effective: A Markov Analysis

INTRODUCTION

Patients infected with the hepatitis C virus (HCV) have high complication rates following total hip arthroplasty (THA). Advances in HCV therapy now enable clinicians to eradicate the disease, however, its cost effectiveness from an orthopaedic perspective remains to be demonstrated. We sought to conduct a cost effectiveness analysis comparing no therapy to direct acting antiviral therapy (DAA) prior to THA among HCV positive patients.

METHODS

A Markov model was utilized to evaluate the cost-effectiveness of treating HCV with DAA prior to THA. The model was powered with event probabilities, mortality, cost and quality adjusted life-year values for patients with and without HCV that were obtained from the published literature. This included treatment costs, successes of HCV eradication, incidences of superficial or periprosthetic joint infection (PJI), probabilities of utilizing various PJI treatment modalities, PJI treatment success/failures, and mortality rates. The incremental cost-effectiveness ratio (ICER) was compared to a willingness-to-pay threshold of $50,000/QALY.

RESULTS

Our Markov model indicates that in comparison to no therapy, DAA prior to THA is cost-effective for HCV positive patients. THA in the setting of no therapy and DAA added 8.06 and 14.39 QALYs at a mean cost of $28,800 and $115,800. The ICER associated with HCV DAA in comparison to no therapy was $13,800/QALY, below the willingness-to-pay threshold of $50,000/QALY.

CONCLUSION

Hepatitis-C treatment with DAA prior to THA is cost-effective at all current drug list prices. Given these findings, strong consideration should be given to treating patients for HCV prior to elective THA.

Viral Glomerulopathy

Background

The association between viral infections and glomerular diseases, commonly known as "viral glomerulopathies," has been described in various clinical scenarios for decades. Despite advancements in diagnostic tools, it remains challenging to establish a causative link fully.

Summary

Data from mouse models have substantiated clinical observations and implicate direct viral infection in the pathogenesis of viral glomerulopathy, particularly in human immunodeficiency virus-associated nephropathy. In addition to the traditional concept of direct viral effects on kidneys, other factors such as APOL1 risk alleles can further modify the clinical outcomes or presentations of different viral glomerulopathies. Newly developed antiviral drugs are now applicable to a wider range of patients with lower kidney function and fewer side effects.

Key Message

Efforts focusing on vaccines and antiviral treatments have significantly reduced the incidence of viral glomerulopathies. However, the most recent pandemic caused by severe acute respiratory syndrome coronavirus 2 infection complicated by COVID-associated nephropathy illustrates our susceptibility to novel viruses. Ongoing research is pivotal to deciphering the mechanisms behind viral glomerulopathies and discovering therapeutics in a collaborative approach.

Virus-Associated Nephropathies: A Narrative Review

While most viral infections cause mild symptoms and a spontaneous favorable resolution, some can lead to severe or protracted manifestations, specifically in immunocompromised hosts. Kidney injuries related to viral infections may have multiple causes related to the infection severity, drug toxicity or direct or indirect viral-associated nephropathy. We review here the described virus-associated nephropathies in order to guide diagnosis strategies and treatments in cases of acute kidney injury (AKI) occurring concomitantly with a viral infection. The occurrence of virus-associated nephropathy depends on multiple factors: the local epidemiology of the virus, its ability to infect renal cells and the patient's underlying immune response, which varies with the state of immunosuppression. Clear comprehension of pathophysiological mechanisms associated with a summary of described direct and indirect injuries should help physicians to diagnose and treat viral associated nephropathies.

Glomerular Disease in Liver Disease

Glomerular diseases are an important cause of kidney disease in patients with liver disease. Although kidney involvement due to tubular or vascular disease is more common, glomerular diseases became more prevalent as hepatitis infections increased and then subsequently decreased with the widespread availability of hepatitis A and B vaccines and the development of effective antiviral treatments for hepatitis B and C. In this review, we discuss the common glomerular pathologies that are seen in patients with liver disease and the current treatment options available to them.

Prevalence and Outcome of Serum Autoantibodies in Chronic Hepatitis C Patients Undergoing Direct-Acting Antiviral Treatment

Background

Chronic immune stimulation by hepatitis C virus (HCV) may cause occurrence of several autoantibodies in infected patients, with or without features of clinically overt autoimmune diseases. The recent introduction of direct-acting antivirals (DAAs) has dramatically changed the natural history of chronic HCV infection. The aim of this study was to assess the effects of DAA therapy on serum autoantibodies in chronic hepatitis C (CHC) patients.

Methods

The medical records of 113 CHC patients were reviewed to assess autoantibody behavior following DAA-directed HCV eradication. Statistical analysis was performed to assess correlations between DAA treatment and autoantibody titers, HCV genotypes, and viral loads.

Results

Anti-nuclear (ANA), anti-smooth muscle cell (ASMA) and anti-mitochondrial (AMA) antibody testing was available in 77 patients; 31 out of 77 patients (40%) had one or more serum autoantibodies prior to treatment. Measurement of autoantibody titers before and after HCV eradication was performed in 20 of 31 patients. DAA treatment significantly affected ANA and ASMA titers, leading to disappearance or reduction of autoantibody titers; conversely, AMA were not influenced by DAA treatment. No correlations were observed between autoantibody specificity and both HCV genotypes and viral loads at baseline. Likewise, serum autoantibody titers were independent of HCV genotypes.

Conclusions

DAA-directed HCV clearance may interrupt chronic immune stimulation by removing the drive for autoantibody induction. The isolated persistence of autoantibodies in the small fraction of patients who did not show clearance following DAA treatment may require long-term vigilance.

Hepatitis C infection and chronic kidney disease among Hispanics/Latinos

ABSTRACT

Viral infections, including hepatitis C, can cause secondary glomerular nephropathies. Studies suggest that hepatitis C virus infection (HCV+) is a risk factor for chronic kidney disease (CKD) but evidence of this relationship is lacking among Hispanics/Latinos. We examined the association between HCV+ and incident CKD in a prospective cohort of Hispanics/Latinos enrolled in the Hispanic Community Health Study/Study of Latinos. HCV+ was defined by detectable HCV antibodies with additional confirmation through HCV RNA or recombinant immunoblot assay testing. Incident CKD was defined by an estimated glomerular filtration rate (eGFR) <60 mL/min/1.73 m2 or sex-specific threshold for albuminuria measured during follow-up. We used Poisson regression to estimate incidence rate ratios (IRR) of CKD and changes in eGFR- or albuminuria-based risk stages, separately. We used linear regression to estimate associations with continuous, annualized changes in eGFR and albuminuria.Over a follow-up period of 5.9 years, 712 incident CKD events occurred among 10,430 participants. After adjustment for demographic characteristics and comorbidities, HCV+ was not associated with incident CKD, defined by eGFR and albuminuria thresholds (IRR 1.29, 95% Confidence Interval 0.61, 2.73). HCV+ was significantly associated with higher eGFR risk stages (IRR 2.39, 95% CI 1.47, 3.61) with most participants transitioning from stage G1 to G2. HCV+ was associated with a continuous, annualized eGFR decline of -0.69 mL/min/m2/year (95% CI -1.23, -0.16). This large, cohort study did not find evidence of a strong association between HCV+ and new-onset CKD among Hispanics/Latinos. HCV infection may not be associated with risk of CKD among Hispanics/Latinos, although treatment with direct-acting antivirals is recommended for all HCV+ individuals, including those with established CKD or end-stage kidney disease.

Perioperative Management of Hepatitis C in Patients Undergoing Total Joint Arthroplasty

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A small yet growing subset of total joint arthroplasty (TJA) candidates are diagnosed with the hepatitis C virus (HCV), which is a known risk factor for periprosthetic joint infections. Given the poor outcomes associated with TJA infection, we recommend that candidates with HCV receive treatment prior to elective TJA.

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Interferon and ribavirin have historically been the standard treatment regimen for the management of HCV; however, adverse events and an inconsistent viral response have limited the efficacy of these therapies. The advent of direct-acting antivirals has resolved many of the issues associated with interferon and ribavirin regimens.

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Despite the success of direct-acting antivirals, there are still barriers to seeking treatment for TJA candidates with HCV. Many patients are faced with financial burdens, as insurance coverage of direct-acting antiviral therapies is inconsistent and varies by the patient's state of residence and specific treatment regimen.

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TJA candidates with HCV present health-care providers with a unique set of challenges, often encompassing economic, psychosocial, and complex medical concerns. Multidisciplinary care teams can be beneficial when caring for and optimizing this patient cohort.

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Management of HCV prior to elective TJA is associated with higher up-front costs but ultimately reduces long-term patient morbidity as well as associated direct and indirect health-care expenditures.

Spectrum of Kidney Diseases in Patients With Hepatitis C Virus Infection

OBJECTIVES

To study the pathologic spectrum of kidney diseases in patients with hepatitis C virus infection (HCV+).

METHODS

Native kidney biopsy specimens in HCV+ patients were reviewed.

RESULTS

A total of 9,836 native kidney biopsy specimens were evaluated from January 2007 to December 2016, of which 273 (2.8%) were from HCV+ patients, and of these, 115 (42.1%) had diagnoses consistent with HCV-associated glomerulonephritis (GN). Non-HCV-associated kidney diseases comprised most diagnoses (158 cases, 57.9%) including non-immune complex-mediated kidney diseases (127 cases, 46.5%) and other immune complex-mediated glomerular diseases (31 cases, 11.4%). Forty-one (40.6%) patients had HCV-associated GN among 101 HCV+ patients from 2007 to 2011 vs 74 (43.0%) patients with HCV-associated GN among 172 HCV+ patients from 2012 to 2016. HCV-associated GN showed five morphologic patterns: focal proliferative (5.2%), diffuse mesangial proliferative (50.4%), diffuse membranoproliferative (28.7%), proliferative GN with crescentic lesions (7.8%), and membranous patterns (7.8%).

CONCLUSIONS

We found a spectrum of pathologic changes in renal biopsy specimens of HCV+ patients, with most having diseases unrelated to HCV infection, HCV-associated GN showing five morphologic patterns, and availability of effective HCV antiviral therapy not yet resulting in major changes in the spectrum of kidney diseases in these patients.

Immune Thrombocytopenic Purpura Complicated by Hepatitis C Virus-related Membranoproliferative Glomerulonephritis after Rituximab Therapy

We herein report the case of a 54-year-old Japanese man with hepatitis C virus (HCV)-related membranoproliferative glomerulonephritis (MPGN), which developed at the time of relapse of immune thrombocytopenic purpura (ITP) after rituximab therapy. Antiviral therapy for HCV led to the improvement of both MPGN and ITP. Rituximab therapy may have contributed to the exacerbation of HCV infection and induced the development of HCV-related MPGN and the relapse of ITP. Our case suggested that HCV treatment should be prioritized over rituximab therapy for HCV-positive patients with ITP and that antiviral therapy for HCV may be effective for treating ITP itself.

Clinical and immunologic implications of COVID-19 in patients with melanoma and renal cell carcinoma receiving immune checkpoint inhibitors

The clinical and immunologic implications of the SARS-CoV-2 pandemic for patients with cancer receiving systemic anticancer therapy have introduced a multitude of clinical challenges and academic controversies. This review summarizes the current evidence, discussion points, and recommendations regarding the use of immune checkpoint inhibitors (ICIs) in patients with cancer during the SARS-CoV-2 pandemic, with a focus on patients with melanoma and renal cell carcinoma (RCC). More specifically, we summarize the theoretical concepts and available objective data regarding the relationships between ICIs and the antiviral immune response, along with recommended clinical approaches to the management of melanoma and RCC patient cohorts receiving ICIs throughout the course of the COVID-19 pandemic. Additional insights regarding the use of ICIs in the setting of current and upcoming COVID-19 vaccines and broader implications toward future pandemics are also discussed.

Interactive Impacts from Hepatitis C Virus Infection and Mixed Cryoglobulinemia on Complement Levels

BACKGROUND/AIM

How hepatitis C virus (HCV) infection and mixed cryoglobulinemia interactively affect complement levels remains elusive, and we aimed to elucidate it.

METHODS

A prospective cohort study of 678 consecutive chronic HCV-infected (CHC) patients was conducted. Of 678, 438 had completed a course of anti-HCV therapy and 362 had achieved a sustained virological response (SVR). The baseline and 24-week post-therapy variables including complement levels and mixed cryoglobulinemia status were surveyed.

RESULTS

At baseline, lower complement component 3 (C3) and component 4 (C4) levels were noted in patients with than those without mixed cryoglobulinemia. The differences between pre-therapy (in 678 CHC patients) and 24-week post-therapy (in 362 SVR patients) factors associated with C3 levels were interferon λ3 (IFNL3) genotype, triglycerides, cirrhosis, and estimated glomerular filtration rate; the different associations with C4 levels were cirrhosis, sex and high sensitivity C-reactive protein. Compared with baseline, SVR patients without pre- and post-therapy mixed cryoglobulinemia had increased C3 levels, and SVR patients with pre-therapy mixed cryoglobulinemia had increased C4 levels. Lower C3 levels were noted in SVR patients with than those without post-therapy mixed cryoglobulinemia.

CONCLUSIONS

HCV might affect C3 levels through IFNL3 genotype, triglycerides, cirrhosis, and renal function; and affect C4 with a link to sex, inflammation, and cirrhosis. That C3 levels decreased in CHC patients without mixed cryoglobulinemia or in SVR patients with post-therapy mixed cryoglobulinemia, and C4 levels decreased in CHC patients with mixed cryoglobulinemia, suggested that mixed cryoglobulinemia and HCV infection antagonistically and synergistically decrease C3 and C4 levels, respectively.

Impact of direct acting antivirals on hepatitis c virus-related cryoglobulinemic syndrome

INTRODUCTION

Mixed cryoglobulinemia (MC) is a B-cell lymphoproliferative disorder largely attributable to HCV infection. MC clinical manifestations are determined by systemic vasculitis of low/medium sized vessels (mixed cryoglobulinemia syndrome or cryoglobulinemic vasculitis and CV) caused by the deposition of cryoglobulins in blood vessels.

EVIDENCE ACQUISITION

A systematic review was performed via the Medline and Scopus databases to evaluate studies concerning CV treatment with new direct antiviral agents (DAAs) and their effect on the syndrome.

EVIDENCE SYNTHESIS

The introduction of Interferon-free protocols has led to more evident positive effects than those observed in the treatment of C hepatitis/cirrhosis. In fact, IFN-free, DAA-based therapy minimised side effects permitting the treatment of previously contraindicated patients and led to a particularly high SVR rate and to a clinical/immunological response in the majority of patients, even if at different levels in different patients, from restitutio ad integrum to partial response. In view of the clearly positive evolution in CV management, the persistence of CV manifestations, in partial or non-responders continues to pose problems in the clinical approach to patients who represent a new condition that is still not completely known.

CONCLUSIONS

Results of DAAs-based therapy strongly confirm the use of anti-HCV therapy as the first-line therapeutic option in CV patients. However, growing evidence of a possible persistence or late relapse of CV suggests the need for longer/more accurate post-DAAs follow-ups as well as biomarkers that are capable of predicting the risk of clinical relapse/persistence to allow for the design of rational post-HCV eradication clinical flow-charts.

[Chronic kidney injury in patients with liver diseases - Reappraising pathophysiology and treatment options]

Acute and chronic kidney disease concurs commonly with liver disease and is associated with a wide array of complications including dialysis dependency and increased mortality. Patients with liver disease or liver cirrhosis show a higher prevalence of chronic kidney disease. This is attributed to concomitant comorbidities, such as metabolic syndrome, chronic inflammation, hypercoagulability, hyperfibrinolysis, diabetes mellitus and dyslipidaemias. But chronic progressive kidney disease is not always due to hepatorenal syndrome. Beyond that, other diseases or disease entities should be considered. Among them are diabetic nephropathy, secondary IgA nephropathy, hepatitis C -associated membranoproliferative Glomerulonephritis (MPGN) and hepatitis B-associated membranous nephropathy.Coexisting diseases, similar underlying pathophysiologic mechanisms, or simultaneously concurring pathophysiological processes and overlapping clinical manifestations, impede the etiologic diagnosis and corresponding treatment of chronic kidney disease in the setting of chronic liver disease. In this review, we focus on common and rare pathologies, which can lead to chronic kidney disease in this particular patient group and try to summarize the most recent therapeutic modalities.

Human hepatitis viruses-associated cutaneous and systemic vasculitis

Human hepatitis viruses (HHVs) include hepatitis A virus, hepatitis B virus (HBV), hepatitis C virus (HCV), hepatitis delta virus, and hepatitis E virus and can cause liver inflammation in their common human host. Usually, HHV is rapidly cleared by the immune system, following acute HHV invasion. The morbidities associated with hepatitis A virus and hepatitis E virus infection occur shortly after their intrusion, in the acute stage. Nevertheless, the viral infectious process can persist for a long period of time, especially in HBV and HCV infection, leading to chronic hepatitis and further progressing to hepatic cirrhosis and liver cancer. HHV infection brings about complications in other organs, and both acute and chronic hepatitis have been associated with clinical presentations outside the liver. Vascular involvement with cutaneous and systemic vasculitis is a well-known extrahepatic presentation; moreover, there is growing evidence for a possible causal relationship between viral pathogens and vasculitis. Except for hepatitis delta virus, other HHVs have participated in the etiopathogenesis of cutaneous and systemic vasculitis via different mechanisms, including direct viral invasion of vascular endothelial cells, immune complex-mediated vessel wall damage, and autoimmune responses with stimulation of autoreactive B-cells and impaired regulatory T-cells. Cryoglobulinemic vasculitis and polyarteritis nodosa are recognized for their association with chronic HHV infection. Although therapeutic guidelines for HHV-associated vasculitis have not yet been established, antiviral therapy should be initiated in HBV and HCV-related systemic vasculitis in addition to the use of corticosteroids. Plasma exchange and/or combined cyclophosphamide and corticosteroid therapy can be considered in patients with severe life-threatening vasculitis manifestations.

Cryoglobulinemic glomerulonephritis: clinical presentation and histological features, diagnostic pitfalls and controversies in the management. State of the art and the experience on a large monocentric cohort treated with B cell depletion therapy

Cryoglobulinemia is defined by the presence of immunoglobulins having the following characteristics: forming a gel when temperature is <37 °C, precipitate in a reversible manner in the serum, and redissolve after rewarming. The presence of both polyclonal IgG and monoclonal IgM (type II), or of polyclonal IgG and polyclonal IgM (type III) identifies the mixed cryoglobulinemia (MC). The identification of the Hepatitis C virus (HCV) infection in most of the cases previously defined as "essential" represented a cornerstone in the understanding the pathogenesis of this condition. The picture of MC comprehends heterogeneous clinical presentations: from arthralgias, mild palpable purpura, fatigue to severe vasculitis features with skin necrotic pattern, peripheral neuropathy and, less commonly, lungs, central nervous system, gastrointestinal tract, and heart involvement. The kidney represents the most common organ presentation, and the presence of glomerulonephritis is a key element when considering prognosis. We discuss the clinical presentation and histological features, diagnostic pitfalls, and controversies in the management of patients with cryoglobulinemic glomerulonephritis, with a special focus on reporting our experience in treating patients with B cell depletion therapy.

Impact of Donor Hepatitis C Virus on Kidney Transplant Outcomes for Hepatitis C-positive Recipients in the Direct-acting Antiviral Era: Time to Revise the Kidney Donor Risk Index?

BACKGROUND

Kidneys from donors with hepatitis C virus (HCV) infection are traditionally considered to be at risk for poorer survival outcomes, as reflected in the kidney donor profile index (KDPI). Modern direct-acting antivirals may modify this risk.

METHODS

Using United Network for Organ Sharing data, HCV-infected adult first-time kidney transplant recipients from 2014 to 2017 were examined. Graft and patient survival were compared in a propensity-matched cohort of recipients of HCV antibody (Ab)(+) kidneys versus Ab(-) kidneys. Subsequent analysis was performed in a propensity-matched cohort of recipients of HCV-viremic (RNA positive) versus HCV-naïve kidneys.

RESULTS

There were 379 recipients each in the matched cohort of recipients of HCV Ab(+) versus HCV Ab(-) kidneys. Despite a higher KDPI (58.2% for HCV Ab[+] versus 38.8% for HCV Ab[-]), 1-year patient and graft survival were similar in the HCV(+) and HCV(-) groups (95.4% and 94.9% versus 97.9% and 96.0%, P = 0.543 and P = 0.834, respectively). There were 200 recipients each in the cohort of recipients of HCV-viremic versus HCV-naïve kidneys, with the KDPI again higher in the HCV-viremic group (56.8% versus 35.2%). Baseline hazard ratios (HRs) for graft failure (HR, 4.69; P = 0.009) and death (HR, 7.60; P = 0.003) were significantly elevated in the viremic group, but crossed 1 at 21 and 24 months, respectively.

CONCLUSIONS

In the modern direct-acting antiviral era, calculated likely KDPI overestimates risk kidneys from HCV (+) donors. Donor viremia conveys an early risk which appears to subside over time. These results suggest that it may be time to revise the kidney donor risk index.

Clinical and Pathophysiological Insights Into Immunological Mediated Glomerular Diseases in Childhood

The kidney is often the target of immune system dysregulation in the context of primary or systemic disease. In particular, the glomerulus represents the anatomical entity most frequently involved, generally as the expression of inflammatory cell invasion or circulant or in situ immune-complex deposition. Glomerulonephritis is the most common clinical and pathological manifestation of this involvement. There are no universally accepted classifications for glomerulonephritis. However, recent advances in our understanding of the pathophysiological mechanisms suggest the assessment of immunological features, biomarkers, and genetic analysis. At the same time, more accurate and targeted therapies have been developed. Data on pediatric glomerulonephritis are scarce and often derived from adult studies. In this review, we update the current understanding of the etiologic events and genetic factors involved in the pathogenesis of pediatric immunologically mediated primitive forms of glomerulonephritis, together with the clinical spectrum and prognosis. Possible new therapeutic targets are also briefly discussed.

Undetectable Hepatitis C Viral Load Is Associated With Improved Outcomes Following Total Joint Arthroplasty

BACKGROUND

Previous reports establish that infection with hepatitis C virus (HCV) predisposes total joint arthroplasty (TJA) recipients to poor postoperative outcomes. The purpose of the present study is to assess whether variation in HCV VL influences perioperative outcomes following TJA.

METHODS

A multicenter retrospective review of all patients diagnosed with HCV who underwent primary TJA between January 2005 and April 2018 was conducted. Patients were stratified into 2 cohorts: (1) patients with an undetectable VL (U-VL) and (2) patients with a detectable VL (D-VL). Kaplan-Meier survivorship analysis was calculated with revision TJA as the end point. Subanalysis on the VL profile was done.

RESULTS

A total of 289 TJAs were included (U-VL:118 TJAs; D-VL:171 TJAs). Patients in the D-VL cohort had longer operative times (133.9 vs 109.2 minutes), higher intraoperative blood loss (298.4 vs 219.5 mL), longer inpatient hospital stays (4.0 vs 2.9 days), more postoperative infections (11.7% vs 4.2%), and an increased risk for revision TJA (12.9% vs 5.1%). Kaplan-Meier demonstrated that the U-VL cohort trended toward better survivorship (P = .17). On subanalysis of low and high VL, no difference in outcomes was appreciated.

CONCLUSION

TJA recipients with a detectable HCV VL have longer operative times, experience more intraoperative blood loss, have longer hospital length of stay, and are more likely to experience infection and require revision TJA. The blood loss, hospital length of stay, and revision rate findings should be interpreted with caution, however, as there are confounding factors. Our findings suggest that HCV VL is a modifiable risk factor that, can reduce the risk of infection and revision surgery. Additionally, serum HCV VL was not correlated with outcomes.

Direct-Acting Antiviral Agents for HCV-Associated Glomerular Disease and the Current Evidence

Glomerular disease is an extra-hepatic manifestation of hepatitis C virus infection (HCV) and membranoproliferative glomerulonephritis is the most frequent glomerular disease associated with HCV. It occurs commonly in patients with HCV-related mixed cryoglobulinemia syndrome. Patients with HCV-related glomerular disease have been historically a difficult-to-treat group. The therapeutic armamentarium for HCV-related glomerular disease now includes antiviral regimens, selective or non-specific immunosuppressive drugs, immunomodulators, and symptomatic agents. The treatment of HCV-associated glomerular disease is dependent on the clinical presentation of the patient. The recent introduction of all-oral, interferon (IFN)-free/ribavirin (RBV)-free regimens is dramatically changing the course of HCV in the general population, and some regimens have been approved for HCV even in patients with advanced chronic kidney disease. According to a systematic review of the medical literature, the evidence concerning the efficacy/safety of direct-acting antiviral agents (DAAs) of HCV-induced glomerular disease is limited. The frequency of sustained virological response was 92.5% (62/67). Full or partial clinical remission was demonstrated in many patients (n = 46, 68.5%) after DAAs. There were no reports of deterioration of kidney function in patients on DAAs. Many patients (n = 29, 43%) underwent immunosuppression while on DAAs. A few cases of new onset or relapsing glomerular disease in patients with HCV successfully treated with DAAs have been observed. In summary, DAA-based combinations are making easier the management of HCV. However, patients with HCV-induced glomerular disease are still a difficult-to-treat group even at the time of DAAs.

Enhancing FcγR-mediated antibody effector function during persistent viral infection

Persistent viral infections can interfere with FcγR-mediated antibody effector functions by excessive immune complex (IC) formation, resulting in resistance to therapeutic FcγR-dependent antibodies. We and others have previously demonstrated that mice persistently infected with lymphocytic choriomeningitis virus (LCMV) are resistant to a wide range of depleting antibodies due to excessive IC formation. Here, we dissect the mechanisms by which two depleting antibodies overcome the obstacle of endogenous ICs and achieve efficient target cell depletion in persistently infected mice. Efficient antibody-mediated depletion during persistent LCMV infection required increased levels of antibody bound to target cells or use of afucosylated antibodies with increased affinity for FcγRs. Antibodies targeting the highly expressed CD90 antigen or overexpressed human CD20 efficiently depleted their target cells in naïve and persistently infected mice, whereas antibodies directed against less abundant antigens failed to deplete their target cells during persistent LCMV infection. In addition, we demonstrate the superior activity of afucosylated antibodies in the presence of endogenous ICs. We generated afucosylated antibodies directed against CD4 and CD8α, which, in contrast to their parental fucosylated versions, efficiently depleted their respective target cells in persistently infected mice. Efficient antibody-mediated depletion can thus be achieved if therapeutic antibodies can outcompete endogenous ICs for access to FcγRs either by targeting highly expressed antigens or by increased affinity for FcγRs. Our findings have implications for the optimization of therapeutic antibodies and provide strategies to allow efficient FcγR engagement in the presence of competing endogenous ICs in persistent viral infections, autoimmune diseases, and cancer.

New insights in cryoglobulinemic vasculitis

Cryoglobulins are antibodies that precipitate at low temperatures and dissolve after rewarming. Cryoglobulinemia refers to the presence of circulating cryoglobulins and generally leads to a systemic inflammatory syndrome characterized by fatigue, arthralgia, purpura, ulcers, neuropathy and/or glomerulonephritis. The disease mainly involves small to medium-sized blood vessels and causes vasculitis due to cryoglobulin-containing immune complexes. Cryoglobulinemia is classified into three types (I, II and III) on the basis of immunoglobulin composition. Predisposing conditions include lymphoproliferative, autoimmune diseases and hepatitis C virus infection. The diagnosis of cryoglobulinemic syndrome is predominantly based on the presence of clinical features and laboratorial demonstration of serum cryoglobulins. The treatment strategy depends on the cause of cryoglobulinemia. For patients with chronic HCV infection, antiviral therapy is indicated. Immunosuppressive or immunomodulatory therapy, including steroids, plasmapheresis and cytotoxic agents, is reserved for organ-threatening manifestations. In this review, we discuss the main clinical presentations, diagnostic approach and treatment options.

Treatment of hepatitis C virus infection in patients with mixed cryoglobulinemic syndrome and cryoglobulinemic glomerulonephritis

Cryoglobulinemia is a common extrahepatic manifestation of infection with hepatitis C virus (HCV). When signs and symptoms of systemic vasculitis or glomerulonephritis occur in the presence of circulating cryoglobulins, this syndrome is called "mixed cryoglobulinemia syndrome" (MCS). Historically, interferon-based therapies in HCV have been associated with lower rates of viral cure in patients with MCS than in the general HCV-infected population. The advent of direct-acting antiviral therapies have revolutionized the treatment of HCV, dramatically increasing rates of cure. Early studies of first-generation protease inhibitors (telaprevir and boceprevir) in combination with interferon and ribavirin demonstrated HCV cure rates of 67% and complete clinical response rates of vasculitis symptoms in 60% of patients with MCS; however, regimens were poorly tolerated by patients, 22% discontinued treatment early. More recently, all-oral, interferon-free regimens have become available and combination therapies are now being approved for patients with and without renal impairment. Patients with HCV-MCS achieved sustained virologic response in 297 out of 313 patients (95%) treated with direct-acting antiviral therapy, and 85% had a complete or partial clinical response of MCS symptoms. Current direct-acting antiviral therapies are well tolerated in patients with HCV-MCS and only 1.6% discontinued treatment early. Patients with cryoglobulinemic glomerulonephritis also had an excellent cure rate (94%). The majority improved; 17/52 (33%) experienced full remission and 15/52 (29%) experienced partial remission. There were no reports of worsening kidney function in patients treated with direct-acting antiviral therapies. Less than 5% of patients with HCV-MCS treated with IFN-free direct-acting antiviral therapy required immunosuppression. However, patients with severe vasculitis appear to still require concomitant immunosuppression.

Cholemic Nephropathy Causes Acute Kidney Injury and Is Accompanied by Loss of Aquaporin 2 in Collecting Ducts

Impairment of renal function often occurs in patients with liver disease. Hepatorenal syndrome is a significant cause of acute kidney injury (AKI) in patients with cirrhosis (HRS-AKI, type 1). Causes of non-HRS-AKI include cholemic nephropathy (CN), a disease that is characterized by intratubular bile casts and tubular injury. As data on patients with CN are obtained primarily from case reports or autopsy studies, we aimed to investigate the frequency and clinical course of CN. We identified 149 patients who underwent kidney biopsy between 2000 and 2016 at the Department of Gastroenterology, Hepatology and Endocrinology at Hannover Medical School. Of these, 79 had a history of liver disease and deterioration of renal function. When applying recent European Association for the Study of the Liver criteria, 45 of 79 patients (57%) presented with AKI, whereas 34 patients (43%) had chronic kidney disease (CKD). Renal biopsy revealed the diagnosis of CN in 8 of 45 patients with AKI (17.8%), whereas none of the patients with CKD was diagnosed with CN. Univariate analysis identified serum bilirubin, alkaline phosphatase, and urinary bilirubin and urobilinogen as predictive factors for the diagnosis of CN. Histological analysis of AKI patients with normal bilirubin, elevated bilirubin, and the diagnosis of CN revealed loss of aquaporin 2 (AQP2) expression in collecting ducts in patients with elevated bilirubin and CN. Biopsy-related complications requiring medical intervention occurred in 4 of 79 patients (5.1%). Conclusion: CN is a common finding in patients with liver disease, AKI, and highly elevated bilirubin. Loss of AQP2 in AKI patients with elevated bilirubin and CN might be the result of toxic effects of cholestasis and in part be responsible for the impairment of renal function.

Hepatitis C virus infection could affect the pathogenesis of ischemic heart diseases in northern Japan

AIMS

Previously, our group reported that lymphotropic hepatitis C virus (HCV) could induce various kinds of immune dysfunctions. The immune dysfunctions could cause vascular disease by inducing cryoglobulinemia. It has been reported that ischemic heart diseases might be caused by HCV. However, the infectious rate of HCV in patients with ischemic heart disease has not been clarified in northern Japan. Therefore, we tried to determine the rate of HCV infectivity in patients with ischemic heart disease.

METHODS

The target patients of this study were automatically selected using an electronic medical record system to exclude selection bias. The system identified 16 484 patients with ischemic heart disease who were included in this study. In addition, 12 902 subjects who had received medical checkups were included as the control group.

RESULTS

The positive rate of HCV antibody among the patients with ischemic disease in our hospital was 2.58%, which was significantly higher (P < 0.01) than in the medical checkup patients (0.84%). The positive rate of HCV antibody in the patients with ischemic heart disease in each age group was significantly higher than in the corresponding age groups of the medical checkup patients. The rate of chronic kidney disease in HCV antibody-positive patients treated by percutaneous coronary intervention (PCI) was significantly higher than in HCV antibody-negative patients treated by PCI (P = 0.02).

CONCLUSIONS

Hepatitis C virus infection might be associated with the pathogenesis of ischemic heart disease and HCV antibody positivity might be a risk factor for ischemic heart disease in northern Japan.

Shedding light on vasculitis in Egypt: a multicenter retrospective cohort study of characteristics, management, and outcome

OBJECTIVES

The frequency of different vasculitides and their characteristics vary among different regions. The identification of geographic disparities of disease phenotypes helps the development of international criteria, allowing the classification of patients of different ethnicities. This study aimed to describe the frequency, characteristics, course, response to treatment, and outcome of the different adulthood vasculitides in Egypt.

METHODS

This was a multicenter study in which the medical records of adult Egyptian patients diagnosed with vasculitis between 2002 and 2018 were retrospectively reviewed.

RESULTS

The most frequent vasculitides in Egypt were Behçet's disease (76%), hepatitis C virus vasculitis (13.9%), and granulomatosis with polyangiitis (3.9%). Most patients (73.8%) had a major event at the time of diagnosis. Generalized granulomatosis with polyangiitis was more common than the localized type (90% versus 10%, respectively). The aortic arch and its branches were the most common affected sites of Takayasu arteritis. Of vasculitides, Behçet's disease and giant cell arteritis were associated with the greatest rates of relapse (62.7% and 33.3%, respectively). Delayed diagnosis and permanent organ damage were reported in 69.9% and 68.9% of patients, respectively. A low mortality rate was noted (1.3%).

CONCLUSIONS

The most common types of adulthood vasculitides in Egypt are Behçet's disease, hepatitis C virus vasculitis, and granulomatosis with polyangiitis. Major organ involvement is frequent. Delayed diagnosis and permanent organ damage are common.

Infection-Related Glomerulonephritis

Acute postinfectious glomerulonephritis or infection-related glomerulonephritis has been associated with several viral or bacterial infections. Group A beta-hemolytic streptococcal infection is the prototypical cause of postinfectious glomerulonephritis and the main focus of this discussion. The clinical spectrum can vary widely, from asymptomatic microscopic hematuria incidentally detected on routine urinalysis to rapidly progressive glomerulonephritis with acute kidney injury requiring emergent dialysis. Other important causes include glomerulonephritis associated with endocarditis and ventriculoatrial shunt infections. Multiple renal pathologic conditions have been associated with hepatitis B and C infections.

Management of hepatitis C virus infection in patients with chronic kidney disease: position statement of the joint committee of Italian association for the study of the liver (AISF), Italian society of internal medicine (SIMI), Italian society of infectious and tropical disease (SIMIT) and Italian society of nephrology (SIN)

Hepatitis C virus (HCV) infection is now considered a systemic disease due to the occurrence of extra-hepatic manifestations. Among these, the renal involvement is frequent. HCV infection, in fact, is strongly associated with proteinuria and chronic kidney disease (CKD) and negatively affects the prognosis of renal patients. In the last few years, availability of more specific and effective drugs against HCV has dramatically changed the clinical course of this disease. These drugs may provide further advantages in the CKD population as a whole by reducing progression of renal disease, mortality rate and by increasing the survival of graft in renal transplant recipients. The strict pathogenetic and prognostic link between HCV infection and CKD requires an ongoing relationship among the healthcare professionals involved in the treatment of both HCV infection and CKD. Therefore, Scientific Societies involved in the care of this high-risk population in Italy have organized a joint expert panel. The aim of the panel is to produce a position statement that can be used in daily clinical practice for the management of HCV infected patients across the whole spectrum of renal disease, from the conservative phase to renal replacement treatments (dialysis and transplantation). Sharing specific evidence-based expertise of different professional healthcare is the first step to obtain a common ground of knowledge on which to instate a model for multidisciplinary management of this high-risk population. Statements cover seven areas including epidemiology of CKD, HCV-induced glomerular damage, HCV-related renal risk, staging of liver disease in patients with CKD, prevention of transmission of HCV in hemodialysis units, treatment of HCV infection and management of HCV in kidney transplantation.

The association of hepatitis C infection with the onset of CKD and progression into ESRD

Hepatitis C virus (HCV) infection is not only an important cause of chronic liver disease, but extrahepatic manifestations are common and include chronic kidney disease (CKD). HCV is classically associated with cryoglobulinemic glomerulonephritis in the context of mixed cryoglobulinemia syndrome, but other glomerular diseases also occur and may be significantly under-recognized. HCV may cause glomerular disease by immune complex deposition; however, other potential mechanisms by which HCV promotes CKD include a direct cytopathic effect of the virus on renal tissue, and by its association with accelerated atherosclerosis, insulin resistance, and chronic inflammation. Epidemiologic studies show HCV infection confers an increased risk of incident CKD and accelerates progression of CKD to end-stage renal disease (ESRD) in the general population, as well as subpopulations including diabetic patients, those coinfected with human immunodeficiency virus (HIV), and kidney transplant recipients. Patients with CKD and HCV infection experience inferior clinical outcomes, including poorer quality of life and an increased risk of mortality. Treatment with interferon-based regimens is associated with decreased risk of incident CKD and ESRD, though prior studies are limited by the small number of patients with HCV and CKD who underwent treatment. With the advent of new, well-tolerated direct-acting antiviral combinations that are not cleared by the kidneys, it is possible to treat all genotypes of HCV infection in patients with CKD and ESRD. More data on the effect of direct-acting antivirals on CKD incidence and progression are necessary. However, there is every expectation that with improved access to HCV treatment, the burden of CKD in patients with HCV could significantly decline.

Management of hepatitis C virus infection in patients with chronic kidney disease: position statement of the joint committee of Italian association for the study of the liver (AISF), Italian society of internal medicine (SIMI), Italian society of infectious and tropical disease (SIMIT) and Italian society of nephrology (SIN)

Hepatitis C virus (HCV) infection is now considered a systemic disease due to the occurrence of extra-hepatic manifestations. Among these, the renal involvement is frequent. HCV infection, in fact, is strongly associated with proteinuria and chronic kidney disease (CKD) and negatively affects the prognosis of renal patients. In the last few years, availability of more specific and effective drugs against HCV has dramatically changed the clinical course of this disease. These drugs may provide further advantages in the CKD population as a whole by reducing progression of renal disease, mortality rate and by increasing the survival of graft in renal transplant recipients. The strict pathogenetic and prognostic link between HCV infection and CKD requires an ongoing relationship among the healthcare professionals involved in the treatment of both HCV infection and CKD. Therefore, Scientific Societies involved in the care of this high-risk population in Italy have organized a joint expert panel. The aim of the panel is to produce a position statement that can be used in daily clinical practice for the management of HCV infected patients across the whole spectrum of renal disease, from the conservative phase to renal replacement treatments (dialysis and transplantation). Sharing specific evidence-based expertise of different professional healthcare is the first step to obtain a common ground of knowledge on which to instate a model for multidisciplinary management of this high-risk population. Statements cover seven areas including epidemiology of CKD, HCV-induced glomerular damage, HCV-related renal risk, staging of liver disease in patients with CKD, prevention of transmission of HCV in hemodialysis units, treatment of HCV infection and management of HCV in kidney transplantation.

Hepatitis C virus infection and chronic renal disease: A review

Hepatitis C virus (HCV) is a parenterally-transmitted hepatotropic virus that often causes chronic infection, which can progress to cirrhosis and hepatocellular carcinoma. Development of highly effective direct-acting anti-viral agents (DAAs) has led to a paradigm change in the treatment of HCV infection over the last 4-5 years. Patients with chronic kidney disease (CKD) are at a higher risk of acquiring HCV infection. In these patients, diagnosis of HCV infection, assessment of the consequent liver disease and management of HCV infection pose some specific problems. This article reviews the available recent information on HCV infection and CKD, including the association between these conditions and their effect on each other, and prevention, evaluation, and management of HCV infection in persons with CKD. This review looks at this issue particularly from the perspective of readers in Asia, especially India, since the epidemiology of HCV-CKD association and the repertoire of anti-HCV drugs available in this region differ from those elsewhere.

Renal complications of liver diseases

Hepatitis B virus (HBV) and hepatitis C virus (HCV) infections are the major causes of chronic liver disease. HBV and HCV affect nearly 7% of the world's population. Extra-hepatic complications and particularly renal failure have different mechanisms and manifestations. The underlying mechanism, although differing for each disease, mainly involves the immune system and antibody deposits in the kidney, which can lead to tissue damage. Areas covered: We do not cover in this review hepatorenal syndrome. We report on the renal complications of viral hepatitis (HBV, HCV, hepatitis E), autoimmune hepatitis, cirrhosis, and Wilson's disease. The most frequent renal disorders are those related to HBV, and HCV due to their high prevalence worldwide. Expert commentary: Thanks to generalization of vaccination against HBV, prevalence of HBV-related liver diseases will decrease, and thereby its associated renal involvement such as polyarteritis nodosa (an exceptional condition), and glomerulonephritis such as membranous nephropathy. Thanks to direct acting antiviral agents HCV infection will be cured within the next decade. However, HCV-related cryoglobulinemia with or without renal involvement might evolve on its own after the patient has eliminated HCV, necessitating then rituximab therapy. Conversely, orofecal-transmitted hepatitis viruses such as hepatitis A and hepatitis E are still very prevalent in developing countries; however, they are rarely associated with renal manifestations.

Uncommon immune-mediated extrahepatic manifestations of HCV infection

INTRODUCTION

Chronic hepatitis C virus (HCV) infection has been associated with myriad extrahepatic manifestations, often resulting from aberrant immune responses. Among the most common immune-mediated manifestations of HCV infection, mixed cryoglobulinemia is the best known extra-hepatic complication. Areas covered: Here we review less common extrahepatic manifestations of HCV infection, with ascertained or presumed immune pathogenesis and the role of the new all oral direct-acting antiviral agents. Rheumatologic, dermatologic, ophthalmologic, renal, pulmonary, hematologic, cardiovascular, and neuropsychiatric manifestations of HCV infection have been considered. Expert commentary: Pathogenesis of HCV-induced aberrant immune responses resulting in peculiar clinical manifestations is not restricted to a single mechanism. A sound approach would therefore consider implementation of an etiologic treatment, through use of antiviral medications, to stop upstream in the pathogenic process all the immune mechanisms leading to hepatic and extrahepatic abnormalities. With the recent introduction of interferon-free, direct antiviral agents, capable of warranting cure for nearly all HCV-infected patients subjected to therapy, both common and uncommon extrahepatic manifestations of chronic hepatitis C are expected to no longer constitute a matter of comorbidity in the course of HCV infection.

Kidney Function Decline in Patients with CKD and Untreated Hepatitis C Infection

BACKGROUND AND OBJECTIVES

Studies evaluating the role of hepatitis C viral (HCV) infection on the progression of CKD are few and conflicting. Therefore, we evaluated the association of untreated HCV on kidney function decline in patients with stage 3-5 CKD.

DESIGN, SETTING, PARTICIPANTS, & MEASUREMENTS

This retrospective cohort study included members of Kaiser Permanente Southern California and Kaiser Permanente Mid-Atlantic States aged ≥18 years, with incident HCV and CKD diagnoses from January 1, 2004 to December 31, 2014. We used generalized estimating equations to compare the rate of change in eGFR between those with HCV and CKD versus CKD alone, adjusting for covariates. Cox proportional hazards models compared the risk of 25% decrease in eGFR and ESKD (defined as progression to eGFR<15 ml/min per 1.73 m2 on two or more occasions, at least 90 days apart) in those with HCV and CKD versus CKD alone, adjusting for covariates.

RESULTS

We identified 151,974 patients with CKD only and 1603 patients with HCV and CKD who met the study criteria. The adjusted annual decline of eGFR among patients with HCV and CKD was greater by 0.58 (95% confidence interval [95% CI], 0.31 to 0.84) ml/min per 1.73 m2, compared with that in the CKD-only population (HCV and CKD, -1.61; 95% CI, -1.87 to -1.35 ml/min; CKD only, -1.04; 95% CI, -1.06 to -1.01 ml/min). Adjusted for covariates, the hazard for a 25% decline in eGFR and for ESKD were 1.87 (95% CI, 1.75 to 2.00) and 1.93 (95% CI, 1.64 to 2.27) times higher among those with HCV and CKD, respectively, compared with those with CKD only.

CONCLUSIONS

Untreated HCV infection was associated with greater kidney function decline in patients with stage 3-5 CKD.

Autoimmune Kidney Diseases Associated with Chronic Viral Infections

Autoimmune kidney diseases triggered by viruses are an important cause of kidney disease in patients affected by chronic viral infection. Hepatitis B virus (HBV) infection is associated with membranous nephropathy and polyarteritis nodosa. Hepatitis C virus (HCV) infection is a major cause of cryoglobulinemic glomerulonephritis. Patients with human immunodeficiency virus (HIV) may develop HIV-associated nephropathy, a form of collapsing focal segmental glomerulosclerosis, or various forms of immune-complex-mediated kidney diseases. This article summarizes what is known about the pathogenesis, diagnosis, and management of immune-mediated kidney diseases in adults with chronic HBV, HCV, and HIV infections.

Achieving Sustained Viral Remission in Patients with Chronic HCV Infection and Cryoglobulinemic Vasculitis Does Not Always Correlate with Normalization of the Serologic Markers

Objective:

We aim to describe the persistence of symptoms associated with HCV-associated cryoglobulinemic vasculitis following achievement of (SVR) with IFN- free direct acting antiviral (DAA) therapy. In particular, we describe the persistence of C4 hypocomplementemia and positive Rheumatoid Factor (RF).

Methods:

We analyzed a case series of four patients enrolled from the Cleveland VA and known to have chronic HCV infection complicated by mixed cryoglobulinemia. The study included patients treated with interferon (IFN) based treatment and IFN free direct acting antiviral (DAA) therapy.

Results:

Of the four patients, patients 1 and 2 experienced decline of RF without resolution following DAA therapy. Patient 1 continues to have evidence of disease following treatment. Patient 3 did not have resolution of RF during IFN-based treatment and experienced stabilization of kidney function while on treatment. Patient 4, previously a non-responder to IFN based treatment, experienced significant decline in RF titers along with resolution of cryoglobulin-associated rash with DAA therapy. C4 remained low following treatment in patients 1 and 3. Of the four patients, only patient 1 had prolonged persistence of cryoglobulinemia, measured at 3%, 17 months following achievement of SVR.

Conclusions:

We highlight the complexity of the viral-mediated immunologic mechanism that causes cryoglobulinemic vasculitis. Our cases also emphasize the need to consider cryoglobulinemic vasculitis as part of the differential diagnosis even with treated HCV infection. Recognizing these findings are important in our understanding of the pathophysiology of the disease and management in the era of IFN-free DAA therapy.

Association of Renal Function and Direct-Acting Antiviral Agents for HCV: A Network Meta-Analysis

The effectiveness and safety of direct-acting antiviral agents (DAAs) in hepatitis C virus (HCV) patients with renal insufficiency remain controversial. Therefore, this network meta-analysis aims to assess effectiveness and safety of DAAs in populations with different renal function. The pooled data were obtained from Cochrane Library, EMBASE, PubMed, and Web of Science. Thirteen studies recruited 6884 patients with hepatitis C infection and reported their outcomes in relation to different levels of renal function after treatment with DAAs. The results showed no difference in the virologic responses among patients with different renal function. Regarding safety, whereas in patients without chronic kidney disease (CKD) or with early CKD DAAs were associated with a risk ratio (RR) of 0.14 (95% confidence interval (CI), 0.04 to 0.43) for renal disorder, increased risk of renal function deterioration was found in advanced-CKD patients, though this effect may be related to the natural course of advanced CKD. Similarly, patients without CKD or with early CKD showed a lower risk of anemia (RR, 0.34; 95% CI, 0.20 to 0.57) and discontinuation (RR, 0.41; 95% CI, 0.39 to 0.56) than patients with advanced CKD. The efficacy of DAAs for HCV treatment was comparable in patients with advanced CKD and in those with early CKD or without CKD. However, the safety of DAAs should be verified in future studies.

Management of hepatitis C virus infection in patients with chronic kidney disease: position statement of the joint committee of Italian association for the study of the liver (AISF), Italian society of internal medicine (SIMI), Italian society of infectious and tropical disease (SIMIT) and Italian society of nephrology (SIN)

Hepatitis C virus (HCV) infection is now considered a systemic disease due to the occurrence of extra-hepatic manifestations. Among these, the renal involvement is frequent. HCV infection, in fact, is strongly associated with proteinuria and chronic kidney disease (CKD) and negatively affects the prognosis of renal patients. In the last few years, availability of more specific and effective drugs against HCV has dramatically changed the clinical course of this disease. These drugs may provide further advantages in the CKD population as a whole by reducing progression of renal disease, mortality rate and by increasing the survival of graft in renal transplant recipients. The strict pathogenetic and prognostic link between HCV infection and CKD requires an ongoing relationship among the healthcare professionals involved in the treatment of both HCV infection and CKD. Therefore, Scientific Societies involved in the care of this high-risk population in Italy have organized a joint expert panel. The aim of the panel is to produce a position statement that can be used in daily clinical practice for the management of HCV infected patients across the whole spectrum of renal disease, from the conservative phase to renal replacement treatments (dialysis and transplantation). Sharing specific evidence-based expertise of different professional healthcare is the first step to obtain a common ground of knowledge on which to instate a model for multidisciplinary management of this high-risk population. Statements cover seven areas including epidemiology of CKD, HCV-induced glomerular damage, HCV-related renal risk, staging of liver disease in patients with CKD, prevention of transmission of HCV in hemodialysis units, treatment of HCV infection and management of HCV in kidney transplantation.

Management of hepatitis C virus infection in patients with chronic kidney disease: position statement of the joint committee of Italian association for the study of the liver (AISF), Italian society of internal medicine (SIMI), Italian society of infectious and tropical disease (SIMIT) and Italian society of nephrology (SIN)

Hepatitis C virus (HCV) infection is now considered a systemic disease due to the occurrence of extra-hepatic manifestations. Among these, the renal involvement is frequent. HCV infection, in fact, is strongly associated with proteinuria and chronic kidney disease (CKD) and negatively affects the prognosis of renal patients. In the last few years, availability of more specific and effective drugs against HCV has dramatically changed the clinical course of this disease. These drugs may provide further advantages in the CKD population as a whole by reducing progression of renal disease, mortality rate and by increasing the survival of graft in renal transplant recipients. The strict pathogenetic and prognostic link between HCV infection and CKD requires an ongoing relationship among the healthcare professionals involved in the treatment of both HCV infection and CKD. Therefore, Scientific Societies involved in the care of this high-risk population in Italy have organized a joint expert panel. The aim of the panel is to produce a position statement that can be used in daily clinical practice for the management of HCV infected patients across the whole spectrum of renal disease, from the conservative phase to renal replacement treatments (dialysis and transplantation). Sharing specific evidence-based expertise of different professional healthcare is the first step to obtain a common ground of knowledge on which to instate a model for multidisciplinary management of this high-risk population. Statements cover seven areas including epidemiology of CKD, HCV-induced glomerular damage, HCV-related renal risk, staging of liver disease in patients with CKD, prevention of transmission of HCV in hemodialysis units, treatment of HCV infection and management of HCV in kidney transplantation.

Association between hepatitis C virus and chronic kidney disease: heterogeneity begets heterogeneity

Epidemiologic studies examining the association between hepatitis C virus and chronic kidney disease have yielded conflicting findings. Analyzing data from a Taiwanese cohort, Lai and colleagues report a novel finding that the odds of chronic kidney disease were nearly 3-fold higher in hepatitis C virus-infected persons with genotype 2 compared with genotype 1. Hepatitis C virus genotype distributions differ in regions around the world. Can genotypic differences in chronic kidney disease risk explain some of the heterogeneity in prior studies?