Hepatitis C virus, cryoglobulinemia, and kidney: novel evidence

Chronic Hepatitis C Virus Infection, Extrahepatic Disease and the Impact of New Direct-Acting Antivirals

Chronic hepatitis C virus infection is an important cause of liver cirrhosis, hepatocellular carcinoma and death. Furthermore, it is estimated that about 40-70% of patients develop non-hepatic alterations in the course of chronic infection. Such manifestations can be immune-related conditions, lymphoproliferative disorders and metabolic alterations with serious adverse events in the short and long term. The introduction of new Direct-Acting Antivirals has shown promising results, with current evidence indicating an improvement and remission of these conditions after a sustained virological response.

Renal Papillary Necrosis (RPN) in an African Population: Disease Patterns, Relevant Pathways, and Management

Renal papillary necrosis (RPN) is characterized by coagulative necrosis of the renal medullary pyramids and papillae. Multiple conditions and toxins are associated with RPN. Several RPN risk factors, or POSTCARDS, have been identified, with most patients presenting with RPN having at least two contributing risk factors. Currently, there is no specific test to diagnose and confirm RPN; however, several imaging tools can be used to diagnose the condition. RPN is currently underdiagnosed in African populations, often with fatal outcomes. In African clinical settings, there is a lack of consensus on how to define and describe RPN in terms of kidney anatomy, pathology, endourology, epidemiology, the identification of African-specific risk factors, the contribution of oxidative stress, and lastly an algorithm for managing the condition. Several risk factors are unique to African populations including population-specific genetic factors, iatrogenic factors, viral infections, antimicrobial therapy, schistosomiasis, substance abuse, and hypertension (GIVASSH). Oxidative stress is central to both GIVASSH and POSTCARDS-associated risk factors. In this review, we present information specific to African populations that can be used to establish an updated consensual definition and practical grading system for radiologists, urologists, nephrologists, nuclear physicians, and pathologists in African clinical settings.

Poricoic Acid A Inhibits the NF-κB/MAPK Pathway to Alleviate Renal Fibrosis in Rats with Cardiorenal Syndrome

Objective

To explore the potential and mechanism of action of poricoic acid A (PAA) in treatment of cardiorenal injury and fibrosis due to cardiorenal syndrome (CRS).

Materials and Methods

A CRS rat model was established by transabdominal subtotal nephrectomy (STNx). The experimental group was treated by gavage of PAA (10 mg/kg/day). After 8 weeks of treatment, echocardiography was utilized for detecting heart-related indexes in rats. HE and Masson staining were conducted to detect the degree of pathological damage and fibrosis in rat kidney tissue, respectively. In addition, serum blood urea nitrogen (BUN), serum creatinine (SCr), and 24-hour urine protein were measured biochemically. Also, the levels of inflammatory factors (IL-1β, IL-6, and IL-10) in rat kidneys were measured using ELISA. Western blot was used to examine the expression of NF-κB/MAPK pathway-related proteins.

Results

In this study, a CRS rat model was successfully established by STNx surgery. PAA treatment could significantly alleviate the damage of heart and kidney function in CRS rats and reduce the pathological damage of kidney tissue and renal fibrosis. Meanwhile, PAA could also inhibit the renal inflammatory response through downregulating IL-1β and IL-6 levels in the kidney tissue and upregulating IL-10 level. Further mechanism exploration showed that the NF-κB/MAPK signaling pathway was significantly activated in CRS rats, while PAA treatment could markedly inhibit the NF-κB/MAPK signaling pathway activity in CRS rats.

Conclusion

PAA can obviously improve the pathological damage and fibrosis of renal tissue in CRS rats and maintain the function of the heart and kidney. The above functions of PAA may be achieved by inhibiting the NF-κB/MAPK signaling pathway activity. Briefly speaking, PAA can serve as a potential drug for CRS treatment.

Direct-acting antiviral therapy improves kidney survival in hepatitis C virus-associated cryoglobulinaemia: the RENALCRYOGLOBULINEMIC study

Background

Direct-acting antiviral agents (DAAs) have shown high rates of sustained virological response in chronic hepatitis C virus (HCV) infection. However, the influence of DAAs on the course of kidney involvement in HCV-associated mixed cryoglobulinaemia (HCV-MC) has been little studied. The aim of this study was to analyse the effects of antiviral treatment on kidney prognosis and evolution in patients diagnosed with HCV-MC.

Methods

The RENALCRYOGLOBULINEMIC study is an observational multicentre cohort study of 139 patients with HCV-MC from 14 Spanish centres. Clinical and laboratory parameters were measured before and after antiviral treatment. Primary endpoints were kidney survival and mortality after HCV-MC diagnosis. Secondary endpoints were clinical, immunological and virological responses after antiviral treatment.

Results

Patients were divided into three groups based on the treatment received: treatment with DAAs (n = 100) treatment with interferon (IFN) and ribavirin (RBV) (n = 24) and no treatment (n = 15). Patients were followed up for a median duration of 138 months (interquartile range 70-251. DAA treatment reduced overall mortality {hazard ratio [HR] 0.12 [95% confidence interval (CI) 0.04-0.40]; P < 0.001} and improved kidney survival [HR 0.10 ( 95% CI 0.04-0.33); P < 0.001].

Conclusions

Results from the RENALCRYOGLOBULINEMIC study indicated that DAA treatment in patients with HCV-MC improves kidney survival and reduces mortality.

Hepatitis C virus antibodies in outpatients with chronic kidney disease

Aim of the study

To determine the seroprevalence of hepatitis C virus (HCV) in outpatients with chronic kidney disease (CKD) attending a nephrology clinic.

Material and methods

Prospective observational study on consecutive outpatients attending a nephrology clinic. Inclusion criteria were age > 18 years, CKD, informed consent. There were no exclusion criterias. Recorded variables were age, gender, CKD grade and etiology, anti-HCV antibodies (Ab). Patients with positive HCV Abs were tracked for HCV RNA detection. Study interval was from November 2015 to March 2016. The study has been approved by the Ethic committee of F.D. Roosevelt University Hospital. Funded by Restricted Grant of AbbVie Slovakia.

Results

One hundred and thirty-four patients were enrolled, with median age 70 years (19.7-91), 52% women. CKD grades: G1/2 – 52 patients (39%), G3a – 34 patients (25%), G3b – 32 patients (24%), G4 – 8 patients (6%), G5 – 8 patients (6%); CKD etiology: tubulointerstitial nephritis (TIN) – 53 patients (40%), nephrosclerosis (NS) – 30 patients (22%), diabetic nephropathy (DN) – 23 patients (17%), glomerulonephritis (GN) – 23 patients (17%), others – 5 patients (4%). Anti-HCV antibodies were detected in 8 patients (6%). There were no significant differences in CKD grades between HCV+ and HCV– patients; Heymann nephritis and GN were significantly more frequent in HCV– patients, as was male gender. Of 8 HCV Ab positive patients, 5 were available for HCV RNA testing (2 died after completion of the study, 1 was lost to follow-up); of them, 1 patient tested positive.

Conclusions

Prevalence of anti-HCV antibodies in CKD patients was 6%, which is 4 times higher than in the general population of Slovakia; HCV RNA was detected in 1 patient (12.5%) of anti-HCV positive patients. Based on this result, multicentric, a larger-scale study is considered to be warranted.

Chronic hepatitis C virus (HCV) increases the risk of chronic kidney disease (CKD) while effective HCV treatment decreases the incidence of CKD

We assessed the risk of chronic kidney disease (CKD) in chronic hepatitis C virus (HCV)-infected patients and the incidence reduction of CKD after receipt of HCV treatment. We also evaluated the risk of membranoproliferative glomerulonephritis (MPGN) and cryoglobulinemia in chronic HCV patients. A retrospective cohort analysis of the Truven Health MarketScan Database (2008-2015) in the United States was conducted. In a cohort of 56,448 HCV-infected patients and 169,344 propensity score (1:3)-matched non-HCV patients, we examined the association of HCV infection with the incidence of CKD. Of 55,818 HCV patients, 6.6 % (n = 3666), 6.3% (n = 3534), and 8.3% (n = 4628) patients received either interferon-based dual, triple, or all-oral direct acting antiviral agent therapy, respectively, whereas 79% of patients did not receive any HCV treatment. Cox proportional hazards models were used to compare the risk of developing CKD in HCV patients compared with non-HCV patients and treated patients compared with untreated HCV patients. In a multivariate time-varying Cox regression model, HCV-infected patients had a 27% increased risk of CKD compared with non-HCV patients (hazard ratio [HR], 1.27; 95% confidence interval [CI], 1.18-1.37). Among HCV patients, individuals who received the minimally effective HCV treatment for dual, triple, or all-oral therapy had a 30% decreased risk of developing CKD (HR, 0.70; 95% CI, 0.55-0.88). In addition, HCV-infected patients experienced a twofold and a nearly 17-fold higher risk of MPGN (HR, 2.23; 95% CI, 1.84-2.71) and cryoglobulinemia (HR, 16.91; 95% CI, 12.00-23.81) respectively, compared with non-HCV patients. Conclusion: HCV-infected individuals in the United States are at greater risk of developing CKD, MPGN, and cryoglobulinemia. Minimally effective treatment of HCV infection can prevent the development of CKD, although the association was not significant for all-oral therapy. (Hepatology 2018;67:492-504).

Managing refractory cryoglobulinemic vasculitis: challenges and solutions

Cryoglobulinemia is thought to be a rare condition. It may be an isolated disorder or secondary to a particular disease. According to immunoglobulin composition, cryoglobulinemia is classified into three types. In mixed cryoglobulinemia (types II and III), vascular deposition of cryoglobulin-containing immune complexes and complement may induce a clinical syndrome, characterized by systemic vasculitis and inflammation – cryoglobulinemic vasculitis (CryoVas). Most common clinical manifestations in CryoVas are skin lesions (orthostatic purpura and ulcers), weakness, peripheral neuropathy, Raynaud’s phenomenon, sicca syndrome, membranoproliferative glomerulonephritis, and arthralgia and seldom arthritis. In patients with mixed cryoglobulinemia, prevalence of anti-hepatitis C virus (HCV) antibodies and/or HCV RNA, detected by polymerase chain reaction (PCR), is reported to be up to 90%, indicating a significant role of HCV in the development of this condition. The goals of therapy for mixed cryoglobulinemia include immunoglobulin level reduction and antigen elimination. CryoVas not associated with HCV infection should be treated according to treatment recommendations for small-vessel vasculitides. CryoVas associated with chronic HCV infection should be treated with antivirals along with immunosuppressive drugs, with or without plasmapheresis, depending on disease severity and organ involvement. Patients who do not respond to first-line therapy may achieve remission when treatment with rituximab is started as second-line therapy. In HCV-related CryoVas, antiviral therapy should be given along with rituximab in order to achieve complete or partial remission. Moreover, rituximab has proven to be a glucocorticoid-sparing medication. Other potential therapies for refractory CryoVas include mycophenolate mofetil and belimumab, while tumor necrosis factor (TNF) inhibitors are not effective.

Treatment of hepatitis C virus-associated mixed cryoglobulinemia with direct-acting antiviral agents

Hepatitis C virus (HCV) is the most common cause of mixed cryoglobulinemia syndrome (MCS). The efficacy and safety of all-oral direct-acting antiviral (DAA) therapy in HCV-associated MCS (HCV-MCS) is largely unknown. The authors studied case series of patients with HCV-MCS who were treated with sofosbuvir-based regimens and historical controls treated with pegylated interferon and ribavirin in a single health care network. HCV-MCS was defined by circulating cryoglobulin associated with systemic vasculitis symptoms. Renal involvement (n = 7) was established by kidney biopsy (n = 5) or by two or more of the following clinical findings: reduced kidney function, proteinuria, or hematuria with other causes excluded (n = 2). Twelve patients received DAA therapy between December 2013 and September 2014. Median age was 61 years, 58% were male, and 50% had cirrhosis. Median baseline serum creatinine was 0.97 mg/dL (range 0.7-2.47). Four patients received rituximab concurrent with DAA therapy. Sustained virological response rate at 12 weeks (SVR12) was 83% overall. Patients with glomerulonephritis who achieved SVR12 experienced an improvement in serum creatinine and a reduction in proteinuria. Cryoglobulin levels decreased in 89% of patients, with median percent decreasing from 1.5% to 0.5% and completely disappearing in four of nine cases who had cryoglobulins measured after treatment. Serious adverse events were infrequent (17%). In contrast, the historical cohort treated with pegylated interferon and ribavirin experienced only 10% SVR12, with 100% experiencing at least one adverse event and 50% experiencing premature discontinuation due to adverse events.

CONCLUSION

SVR12 rates for sofosbuvir-based DAA regimens in HCV-MCS were 83%, significantly higher than historical controls treated with pegylated interferon and ribavirin; patients with glomerulonephritis experienced improvement in renal function, including those not concomitantly treated with immunosuppression.

HIV-associated immune complex kidney disease

The introduction in the late 20(th) century of combination antiretroviral therapy (cART) to treat patients infected with HIV has changed the natural history of the disease from an acute illness that rapidly culminates in death, to a chronic condition that can be managed with medications. Over the past decade the epidemiology of kidney disease in US patients infected with HIV has changed, perhaps because of the increased availability and use of cART. Patients with HIV infection exhibit unique immunologic characteristics, including immunodeficiency and dysregulation of immunoglobulin synthetic responses and T-cell function, which can result in glomerular immune complex deposition and subsequent kidney injury. This Review examines the differential diagnoses of HIV-associated immune complex kidney diseases (HIVICD), and discusses the clinical manifestations and mechanisms underlying their development. We address the issues associated with treatment, clinical outcomes, and research needs to enhance our ability to diagnose and optimally treat patients with HIVICD.

The incidence of possible causes of membranoproliferative glomerulonephritis: a single-center experience

BACKGROUND

Diagnosis of membranoproliferative glomerulonephritis (MPGN) is based on kidney biopsy findings: unique glomerular injury pattern and characteristic changes on light, electron microscopy and immunohistochemical analysis. The purpose of this study was to identify possible etiology and incidence of glomerular injury among patients with a diagnosed MPGN.

MATERIALS AND METHODS

A retrospective analysis (years 2000-2014) of 81 clinical cases with a diagnosis of MPGN based on biopsy results was performed. Records were examined, and data about viral, bacterial infections, autoimmune and hematological diseases was collected. Test results of blood C3 and C4 factors of the complement system, and results of kidney biopsy immunohistochemical analysis were investigated. Statistical analysis was performed using Statistical Package for the Social Sciences and p-value less than 0.05 was considered statistically significant.

RESULTS

Study population consisted of 55 males (67.9%) and 26 females (32.1%). The average patients' age was 48.53 (standard deviation ± 16.67) years. The identified etiology of MPGN was: idiopathic in 26 cases (32.10%), bacterial infections in 20 cases (24.69%), viral hepatitis in 16 cases (19.75%), autoimmune diseases in 11 cases (13.58%), and hematological diseases in eight cases (9.88%). Changes of the concentration of complement component C3 as well as component C4 were found; their concentration was decreased in 26 (32.1%) and 17 (20.99%) patients' respectively while concentration was within the normal range in 11 (13.58%) and 19 (23.46%) patients respectively. Immunohistochemistry results revealed immunoglobulin (Ig) deposits: C3+/Ig+ was found in 47 (58.02%) cases, C3-/Ig+ was found in 16 (19.75%) cases and in six (7.41%) cases test was not performed. The total number of immunoglobulin positive biopsies (C3+/Ig+ and C3-/Ig+, also called immune-complex mediated MPGN) was 63 (77.78%). Complement-mediated MPGN (C3+/Ig-) was less common and was diagnosed only in seven cases (8.64%). C3-/Ig- was found in five cases (6.17%).

CONCLUSIONS

The leading cause of MPGN was idiopathic as well as bacterial infections. Complement component C3 concentration was mostly decreased. The incidence of normal and decreased concentration of the complement component C4 was almost equal. Most immunohistochemical deposits in kidney biopsy appeared to be C3/Ig positive, and it was observed in more than half of the cases of each MPGN etiological group. Hippokratia 2015; 19 (4): 314-318.

Vasculitis with renal involvement in essential mixed cryoglobulinemia: Case report and mini-review

The discovery of a strong association between hepatitis C virus (HCV) infection and mixed cryoglobulinemia (MC) has led to an increasingly rare diagnosis of idiopathic essential MC (EMC). The incidence of EMC is high in regions where there is a comparatively low HCV infection burden and low in areas of high infection prevalence, including HCV. The diagnosis of EMC requires an extensive laboratory investigation to exclude all possible causes of cryoglobulin formation. In addition, although cryoglobulin testing is simple, improper testing conditions will result in false negative results. Here, we present a 46-year-old female patient with a case of EMC with dermatological and renal manifestations, highlighting the importance of extensive investigation to reach a proper diagnosis. We review the need for appropriate laboratory testing, which is often neglected in clinical practice and which can result in false negative results. This review also emphasizes the significance of an extended testing repertoire necessary for better patient management. Despite a strong association of MC with HCV infection and other causes that lead to cryoglobulin formation, EMC remains a separate entity. Correct diagnosis requires proper temperature regulation during sample handling, as well as characterization and quantification of the cryoprecipitate. Inclusion of rheumatoid factor activity and complement levels in the cryoglobulin test-panel promotes better patient management and monitoring. Consensus guidelines should be developed and implemented for cryoglobulin detection and the diagnosis of cryoglobulinemic syndrome, which will reduce variability in inter-laboratory reporting.