Kinetics of hepatitis C viral RNA and HCV-antigen during dialysis sessions: evidence for differential viral load reduction on dialysis

Ultrasensitive electrochemical detection of hepatitis C virus core antigen using terminal deoxynucleotidyl transferase amplification coupled with DNA nanowires

Early diagnosis of hepatitis C virus (HCV) infection is essential to prevent disease from spreading and progression. Herein, a novel electrochemical biosensor was developed for ultrasensitive detection of HCV core antigen (HCVcAg) based on terminal deoxynucleotidyl transferase (TdT) amplification and DNA nanowires (DNW). After sandwich-type antibody-antigen recognition, the antibody-conjugated DNA was pulled to the electrode surface and further extended into a long DNA sequence by robust TdT reaction. Then, large numbers of methylene blue-loaded DNW (MB@DNW) as signal labels are linked to the extended DNA sequence. This results in an amplified electrochemical signal for HCVcAg determination, typically measured at around -0.25 V (Ag/AgCl). Under the optimum conditions, the proposed biosensor achieved a wide linear range for HCVcAg from 0.1 to 312.5 pg/mL with a low limit of detection of 32 fg/mL. The good practicality of the biosensor was demonstrated by recovery experiment (recoveries from 98 to 104% with RSD of 2.5-4.4%) and comparison with enzyme-linked immunosorbent assay (ELISA). Given the highlighted performance, the biosensor is expected to act as a reliable sensing tool for HCVcAg determination in clinics. Schematic representation of the ultrasensitive electrochemical biosensor based on terminal deoxynucleotidyl transferase (TdT) amplification linked with methylene blue-loaded DNA nanowires (MB@DNW), which can be applied to the determination of hepatitis C virus core antigen (HCVcAg) in clinical samples. dTTPs, 2'-deoxythymidine 5'-triphosphate.

Hepatitis C virus antigens enzyme immunoassay for one-step diagnosis of hepatitis C virus coinfection in human immunodeficiency virus infected individuals

BACKGROUND

Current diagnosis of hepatitis C virus (HCV) infection requires two sequential steps: testing for anti-HCV followed by HCV RNA PCR to confirm viremia. We have developed a highly sensitive and specific HCV-antigens enzyme immunoassay (HCV-Ags EIA) for one-step diagnosis of viremic HCV infection.

AIM

To assess the clinical application of the HCV-Ags EIA in one-step diagnosis of viremic HCV infection in human immunodeficiency virus (HIV)-coinfected individuals.

METHODS

The study blindly tested HCV-Ags EIA for its performance in one-step diagnosing viremic HCV infection in 147 sera: 10 without HCV or HIV infection; 54 with viremic HCV monoinfection; 38 with viremic HCV/HIV coinfection; and 45 with viremic HCV and non-viremic HIV coinfection.

RESULTS

Upon decoding, it was 100% accordance of HCV-Ags EIA to HCV infection status by HCV RNA PCR test. In five sera with HCV infection, HCV RNA was as low as 50-59 IU/mL, and four out of five tested positive for HCV-Ags EIA. Likewise, it was also 100% accordance of HCV-Ags EIA to HCV infection status by HCV RNA PCR in 83 sera with HCV and HIV coinfection, regardless if HIV infection was active or not.

CONCLUSION

The modified HCV-Ags EIA has a lower detection limit equivalent to serum HCV RNA levels of approximately 100 IU/mL. It is highly sensitive and specific in the setting of HIV coinfection, regardless of HIV infection status and CD4 count. These data support the clinical application of the HCV-Ags EIA in one-step diagnosis of HCV infection in HIV-infected individuals.

Hepatitis C Infection in Hemodialysis Patients

Three centuries after the identification of hepatitis C virus (HCV), specialized literature has outlined the epidemiology, viral kinetics and clinical manifestations of this infection. A major cause of morbidity-mortality in patients with renal transplantation and in hemodialysis patients is HCV infection. In high seroprevalence countries, internal accounts are not uniform. The European trend is to decrease the incidence and prevalence of HCV in hemodialysis patients. In Europe, the prevalence of HCV infection among hemodialysis patients tends to be higher than that of the general population, but it is variable by region. Some studies indicate a decrease in incidence in parallel with prevalence in dialysis centers over the last 10 years, while others maintain a high incidence. In some countries, as is the case with Romania, both prevalence and incidence remain high, with the major route of transmission being nosocomial, probably due to limited resources for a rapidly growing dialyzed population. Some authors recommend more isolation measures to be taken in centers with high prevalence of infection.

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.

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.

Hepatitis C virus core antigen for screening organ donors and recipients

Organ donors and recipients are routinely screened for hepatitis C virus (HCV) infection, typically via anti-HCV detection. We analyze the utility of an alternative HCV core antigen (HCV-Ag) quantification system, the ARCHITECT HCV Ag Assay, in this setting. We simultaneously tested 315 samples from potential organ donors and recipients using two chemiluminescent microparticle immunoassays: ARCHITECT Anti-HCV and HCV Ag (Abbott, Germany). HCV-Ag was detected in 81 of the serum samples (25.71%) and anti-HCV in 87 (27.62%). Seventy-five of the HCV-Ag-positive samples were positive for anti-HCV (92.59%). Overall concordance between the two assays was 94.29%. Of the six HCV-Ag-positive/anti-HCV-negative patients, five had HCV-Ag values <32 fmol/L, and the sixth had a concentration of 477.50 fmol/L (viral load, 137,000 IU/mL). The HCV AG Assay detects HCV infections missed by the Anti-HCV Assay. Both markers should be used to screen for HCV infection in potential organ donors and recipients.

Hepatitis C virus infection in maintenance hemodialysis patients: recommendations for diagnostics and treatment

Hepatitis C virus (HCV) infection is highly prevalent among patients treated with maintenance hemodialysis and is an important cause of morbidity and mortality. It is necessary to determine the HCV genotype and the viral load to monitor the clinical and laboratory features and to establish an optimal antiviral treatment strategy. Antiviral treatments are presented with a standard interferon-based regimen and new direct-acting antiviral agents. The advent of direct-acting antivirals has improved the efficacy and safety of HCV treatment for most patients, even in difficult-to-treat populations such as patients on hemodialysis. HCV treatment with direct-acting antivirals in hemodialysis patients is highly effective, with viral eradication rates similar to those seen in patients without chronic kidney disease and with acceptable adverse event profiles.

A highly specific and sensitive hepatitis C virus antigen enzyme immunoassay for One-step diagnosis of viremic hepatitis C virus infection

The current standard in diagnosing hepatitis C virus (HCV) infection requires two sequential steps: anti-HCV test to screen, followed by HCV RNA reverse-transcription polymerase chain reaction to confirm viremic HCV (V-HCV) infection. HCV core antigen tests provided potential for possible one-step diagnosis. However, low sensitivity and specificity limit their clinical utility. The present study developed a novel HCV antigens enzyme immunoassay (HCV-Ags EIA) and assessed its sensitivity, specificity, and utility for one-step diagnosis of V-HCV infection using 365 serum specimens, including 176 without and 189 with V-HCV infection. First, we confirmed the presence of HCV nonstructural proteins 3, 4b, and 5a besides HCV core antigen during HCV infection and developed a novel HCV-Ags EIA through simultaneous detection of all four HCV proteins. For the first time, the present study demonstrated that serum sample denaturation decreases the test specificity due to release of HCV-Ags sequestered in HCV immune complexes and should not be used in any HCV-Ags, including all the current HCV core antigen assays. On the other hand, using sample nondenaturation, the HCV-Ags EIA results showed 98.9% specificity and 100% sensitivity compared to serum anti-HCV and HCV RNA reverse-transcription polymerase chain reaction results. Using serum sample dilution, and nondenaturation, the lowest limits of detection of the HCV-Ags EIA were equivalent to serum HCV RNA levels of approximate 150-250 IU/mL.

CONCLUSIONS

The highly specific and sensitive HCV-Ags EIA developed in the present study has the lowest limit of detection equivalent to serum HCV RNA levels of 150-250 IU/mL; using nondenaturation of serum samples, our HCV-Ags EIA reliably differentiated V-HCV infection from resolved HCV infection, accomplishing screening and diagnosis of V-HCV infection in one step. (Hepatology 2016;64:415-424).

Relevance of low viral load in haemodialysed patients with chronic hepatitis C virus infection

AIM

To identify predictors of sustained virological response in hemodialysed patients treated by PEGinterferon α for chronic hepatitis C, genotype 1.

METHODS

The sustained virological response (SVR) rate, IL28B genotype, IFNL4 genotype, initial viral load (IVL) and other pretreatment variables in 39 end-stage renal disease patients (ESRD) on maintenance haemodialysis (HD) infected with hepatitis C virus (HCV), genotype 1b, were compared with a control group of 109 patients with normal kidney function treated within the same period. All the patients were treatment naïve and had well compensated liver disease. The ESRD patients received 135 μg of PEGylated interferon α-2a (PegIFN-α) weekly and a reduced dose of ribavirin (RBV) was administered to 23/39 patients with an initial haemoglobin level > 10 g/dL. Control group patients were given standard doses of PegIFN-α and RBV. SVR was assessed as HCV RNA negativity 24 wk post-treatment. A t-test or ANOVA were used for comparisons of the means and a χ(2) test compared the frequencies. Logistic regression was used to determine significant predictors of SVR. Cutoff values for continuous variables were obtained from Receiver Operating Characteristic analysis.

RESULTS

The distribution of IL28B rs12979860 CC, CT and TT genotypes in the ESRD group was 28.2%, 64.1% and 7.7%, respectively, and 19.3%, 62.4% and 18.3% in the controls. The IFNL4 genotype was in almost absolute linkage disequlibrium with IL28B. The proportion of patients with a low IVL (< 600000 IU/mL) was significantly higher in the ESRD group than in the controls (28/39, 71.8% vs 51/109, 46.8%, P = 0.009), as was the proportion of patients with low IVL in IL28B CC carriers compared with non-CC carriers in the ESRD group (10/11, 90.9% vs 18/28, 64.3%, P = 0.0035). This difference was not found in the controls (7/22, 31.8% vs 44/87, 50.6%, P = 0.9). The overall SVR rate was 64.1% (25/39) in the ESRD group and 50.5% (55/109) in the control group (P = 0.19). 11/11 (100%) and 19/22 (86.4%) IL28B CC patients achieved SVR in the ESRD and control groups, respectively. A statistically significant association between SVR and IL28B and IFNL4 variants was found in both groups. The ESRD patients who achieved SVR showed the lowest IVL [median 21000, interquartile range (IQR): 6000-23000 IU/mL], compared with ESRD individuals without SVR (1680000, IQR: 481000-6880000, P = 0.001), controls with SVR (387000, IQR: 111000-1253000) and controls without SVR (905000, IQR: 451000-3020000). In ESRD, an IVL < 600000 IU/mL was strongly associated with SVR: 24/28 (85.7%) patients who achieved SVR had viraemia below this threshold.

CONCLUSION

Haemodialysis decreases the viral load, especially in IL28B CC genotype carriers. A low IVL was the strongest predictor of SVR in ESRD patients identified in multivariate analysis.

Hepatitis C infection in hemodialysis patients: A review

Hepatitis C virus (HCV)-related liver disease is a significant cause of morbidity and mortality in patients with end-stage renal disease (ESRD) who is treated with dialysis or kidney transplantation (KT). The survival rate for HCV-infected renal transplant recipients is better than that for HCV-infected hemodialysis patients on transplant waiting lists. Early diagnosis and treatment HCV infection prior to KT prevents complications post-transplantation and reduces mortality. In addition to screening for anti-HCV antibodies and detecting HCV RNA, percutaneous liver biopsy is particularly valuable for assessing the stage of liver damage in HCV-infected patients, because the stage of fibrosis is important determining optimal treatment for HCV. Studies have been demonstrated that with conventional interferon (IFN) monotherapy or pegylated IFN monotherapy are similar efficacy and safety in HCV-infected hemodialysis patients. Sustained viral responses (SVRs) with these monotherapies have ranged approximately 30% to 40%. Limited reports support the use of IFN and ribavirin combination therapy as antiviral treatment for ESRD patients or patients on hemodialysis. Ribavirin can be started at low dose and careful monitoring for side effects. Patients that show SVR after treatment are strong candidates for KT. It is also generally accepted that ESRD patients with decompensated cirrhosis and portal hypertension should be referred to the liver transplant team for consideration of combined liver-KT.

Histological features of chronic hepatitis C in haemodialysis patients

BACKGROUND & AIMS

HCV infection in haemodialysis (HD) patients is still a matter of investigation. The aim of this study was to determine the histology of chronic hepatitis C (CHC) in HCV-infected HD patients within the context of a comparative analysis including non-uraemic patients with CHC. The relative importance of virological, demographic and clinical parameters on disease manifestation was examined.

METHODS

Sixty-one consecutive liver biopsies from HD patients and 326 from non-uraemic patients with chronic HCV infection were comparatively evaluated.

RESULTS

Haemodialysis patients with CHC were older than control subjects (P = 0.031), showing a similar HCV genotype distribution (P = 0.328) and lower viral load (P = 0.001). CHC in HD patients was significantly milder according to stage (P = 0.033), grade and its parameters (periportal activity, portal inflammation and lobular activity) (P < 0.001). The frequency of lymphoid aggregates (10.2% vs. 50%, P < 0.001), bile duct lesions (1.7% vs. 22.1%, P < 0.001) and extent of steatosis (P = 0.022) in HD group was significantly reduced. Multivariate analysis showed that non-uraemic patients had 2.3 times higher risk of developing steatosis independently of genotype distribution and age. In HD group, genotype 3, longer HD duration and age at infection were significantly associated with steatosis, while older age at infection correlated with advanced fibrosis.

CONCLUSIONS

Chronic hepatitis C in HD patients is usually very mild, losing its diagnostic histological features while patient's age and age at infection retain their prognostic significance. The weak inflammatory response, probably because of immunocompromised status and low viral load, may present a beneficial factor in the natural course of the disease.

Liver enzymes serum levels in patients with chronic kidney disease on hemodialysis: a comprehensive review

We reviewed the literature regarding the serum levels of the enzymes aspartate aminotransferase, alanine aminotransferase, and gamma-glutamyl transferase in patients with chronic kidney disease on hemodialysis with and without viral hepatitis. Original articles published up to January 2013 on adult patients with chronic kidney disease on hemodialysis were selected. These articles contained the words "transaminases" "aspartate aminotransferase" "alanine aminotransferase" "gamma glutamyl transferase," "liver enzymes", AND "dialysis" OR "hemodialysis". A total of 823 articles were retrieved. After applying the inclusion and exclusion criteria, 49 articles were selected. The patients with chronic kidney disease on hemodialysis had reduced serum levels of aminotransferases due to hemodilution, lower pyridoxine levels, or elevated homocysteine levels. The chronic kidney disease patients on hemodialysis infected with the hepatitis C virus also had lower aminotransferase levels compared with the infected patients without chronic kidney disease. This reduction is in part due to decreased viremia caused by the dialysis method, the production of a hepatocyte growth factor and endogenous interferon-α, and lymphocyte activation, which decreases viral action on hepatocytes. Few studies were retrieved on gamma-glutamyl transferase serum levels; those found reported that there were no differences between the patients with or without chronic kidney disease. The serum aminotransferase levels were lower in the patients with chronic kidney disease on hemodialysis (with or without viral hepatitis) than in the patients with normal renal function; this reduction has a multifactorial origin.

Japanese reference panel of blood specimens for evaluation of hepatitis C virus RNA and core antigen quantitative assays

An accurate and reliable quantitative assay for hepatitis C virus (HCV) is essential for measuring viral propagation and the efficacy of antiviral therapy. There is a growing need for domestic reference panels for evaluation of clinical assay kits because the performance of these kits may vary with region-specific genotypes or polymorphisms. In this study, we established a reference panel by selecting 80 donated blood specimens in Japan that tested positive for HCV. Using this panel, we quantified HCV viral loads using two HCV RNA kits and five core antigen (Ag) kits currently available in Japan. The data from the two HCV RNA assay kits showed excellent correlation. All RNA titers were distributed evenly across a range from 3 to 7 log IU/ml. Although the data from the five core Ag kits also correlated with RNA titers, the sensitivities of individual kits were not sufficient to quantify viral load in all samples. As calculated by the correlation with RNA titers, the theoretical lower limits of detection by these core Ag assays were higher than those for the detection of RNA. Moreover, in several samples in our panel, core Ag levels were underestimated compared to RNA titers. Sequence analysis in the HCV core region suggested that polymorphisms at amino acids 47 to 49 of the core Ag were responsible for this underestimation. The panel established in this study will be useful for estimating the quality of currently available and upcoming HCV assay kits; such quality control is essential for clinical usage of these kits.

Is hepatitis C virus core antigen an adequate marker for community screening?

A new hepatitis C virus (HCV) core antigen (HCV Ag) assay was thought to have a good correlation with HCV RNA. The aim was to elucidate the usefulness of this HCV Ag assay in community screening. In a township where HCV is endemic, 405 residents aged 58 years or older responded to a follow-up community screening. All subjects were tested for anti-HCV (AxSYM, version 3.0; Abbott Diagnostics) and HCV Ag (Architect HCV Ag test; Abbott Diagnostics). For subjects with anti-HCV signal-to-cutoff ratios (S/CO) > 10 and/or HCV Ag > 3 fmol/liter, HCV RNA data (Taqman HCV RNA; Roche Diagnostics) were further checked. A total of 115 (28.4%) subjects had their serum HCV RNA levels measured, and 93 were HCV RNA positive. The other 290 subjects were supposed to be HCV RNA negative. HCV Ag was significantly correlated with HCV RNA according to the following equation: (log HCV RNA) = 2.08 + 1.03 (log HCV Ag) (R(2) = 0.94; P < 0.001). As determined using a combination of the values for anti-HCV (S/CO > 40) and HCV Ag (>3 fmol/liter) as a cutoff to predict viremia, the sensitivity, specificity, accuracy, positive predictive value, and negative predictive value were 96.8%, 100%, 99.3%, 100%, and 99%, respectively. In conclusion, for a community study, HCV Ag showed good correlation with HCV RNA. In addition, anti-HCV or HCV Ag can predict HCV viremia well, while a combination of anti-HCV (>40 S/CO) and HCV Ag (>3 fmol/liter) can provide the best result validity.

Kinetics of hepatitis C virus load and hemodialysis: is there any influence of the reuse of dialysis membrane on HCV viremia?

BACKGROUND

Patients with chronic kidney disease (CKD) on regular hemodialysis are at increased risk of acquiring hepatitis C virus (HCV). Although controversial, a distinct dynamic of the HCV load has been reported in this group - a lower HCV viremia compared to non-uremic patients. The reasons for this remain unclear, but the host immune response related to the hemodialysis procedure and the reuse of dialysis membranes are the most investigated factors.

METHODS

We analyzed the kinetics of HCV RNA viremia in 21 hemodialysis patients infected with genotype 1, through a highly sensitive quantitative method (real-time polymerase chain reaction), immediately before and at the end of the first use and the last reuse of the cellulose diacetate dialysis membrane.

RESULTS

Initial HCV load did not correlate with demographic or biochemical parameters, but higher HCV viremia was associated with a longer time on hemodialysis (r = 0.44, p = 0.04). Although not significant, HCV RNA decreased in 11/21 (52.3%) patients after the first dialysis session (median 279,000 vs 176,000 IU/ml, p = 0.91). However, a significant increase in HCV RNA viremia was observed in 17/21 (80.9%) patients after the tenth session (median 187,000 vs 342,000 IU/ml, p = 0.009).

CONCLUSIONS

Except for the first session of hemodialysis, we did not confirm a decrease in HCV viremia related to the time on hemodialysis or with the reuse of the dialysis membrane. Factors other than the reuse of the dialysis membrane might be involved in the multifaceted kinetics of HCV RNA in CKD patients on hemodialysis.

Hepatitis C virus core antigen: analytical performances, correlation with viremia and potential applications of a quantitative, automated immunoassay

BACKGROUND

Testing for hepatitis C virus core antigen (HCV Ag) may represent a complementary tool to anti-HCV and HCV-RNA in the diagnosis and monitoring of HCV infection.

OBJECTIVE

To evaluate the performance characteristics of the automated Abbott ARCHITECT HCV Ag assay.

STUDY DESIGN

Five sites analyzed over 3000 routine serum samples from populations at different risk, comparing HCV Ag results with anti-HCV screening and supplemental assay results and with HCV-RNA.

RESULTS

The HCV Ag assay showed a specificity of 100%, a good precision (CV<10%) and excellent dilution linearity (r>0.999). The sensitivity (3 fmol/L) corresponds to 700-1100 IU/mL of HCV-RNA. A non-linear correlation with HCV-RNA was found: r=0.713 vs. Siemens bDNA (523 specimens), r=0.736 vs. Roche Cobas TaqMan (356 specimens) and r=0.870 vs. Abbott Real-Time PCR (273 specimens). HCV Ag quantitation was equally effective on different HCV genoypes (239 for genotype 1/1a/1b/1c, 108 for genotype 2/2a/2c, 86 for genotype 3/3a, 50 for genotype 4/4a/4c/4d). Testing of subjects at high risk for HCV and with potential or actual impairment of the immune system identified 2 cases negative for anti-HCV and positive for HCV Ag on 361 hemodialyzed (0.6%) and 7 cases on 97 (7.2%) among transplant recipients. HCV Ag positivity anticipated anti-HCV seroconversion in all three cases of acute hepatitis C.

CONCLUSIONS

HCV Ag may be used as reflex testing on anti-HCV positive individuals to confirm or exclude an active infection, and on subjects with acute hepatitis or belonging to high risk groups.

Treatment of hepatitis C virus infection in patients with end-stage renal disease

Hepatitis C virus (HCV) infection is a major health problem in patients with end-stage renal disease (ESRD). The incidence of acute HCV infection during maintenance dialysis is much higher than that in the general population because of the risk of nosocomial transmission. Following acute HCV infection, most patients develop chronic HCV infection, and a significant proportion develop chronic hepatitis, cirrhosis, and even hepatocellular carcinoma. Overall, chronic hepatitis C patients on hemodialysis bear an increased risk of liver-related morbidity and mortality, either during dialysis or after renal transplantation. Interferon (IFN) therapy is modestly effective for the treatment of HCV infection in ESRD patients. Conventional or pegylated IFN monotherapy has been used to treat acute hepatitis C in ESRD patients with excellent safety and efficacy. Regarding chronic hepatitis C, approximately one-third of patients can achieve a sustained virological response (SVR) after conventional or pegylated IFN monotherapy. The combination of low-dose ribavirin and conventional or pegylated IFN has further improved the SVR rate in treatment-naïve or retreated ESRD patients in clinical trials. Similar to the treatment of patients with normal renal function, baseline and on-treatment HCV virokinetics are useful to guide optimized therapy in ESRD patients. Of particular note, IFN-based therapy is not recommended at the post-renal transplantation stage because of the low SVR rate and risk of acute graft rejection. In conclusion, ESRD patients with HCV infection should be encouraged to receive antiviral therapy, and those who achieve an SVR usually have long-term, durable, virological, biochemical, and histological responses.

Analytical evaluation of HCV core antigen and interest for HCV screening in haemodialysis patients

BACKGROUND

It is important to diagnose a hepatitis C virus infection in the acute phase in order to reduce the incidence of this infection in high-risk populations like haemodialysis patients. But detection systems for serum HCV antibodies are insensitive in the acute phase because of the long serological window. Previous studies showed that the HCV core antigen (HCV Ag) may be an alternative to HCV RNA in this context.

OBJECTIVES

To evaluate the performances of the new Abbott ARCHITECT((R)) HCV Ag test and its usefulness in screening for HCV infections in haemodialysis patients.

STUDY DESIGN

The serum HCV Ag titre was compared to the HCV RNA viral load in 98 samples from HCV-infected patients to determine the correlation between the two markers and the influence of genotype. We screened 2752 patients from 37 French haemodialysis units who tested negative for HCV antibodies using the HCV Ag and RNA assays.

RESULTS

The HCV Ag titre was correlated with the HCV RNA (Spearman test coefficient 0.9041, p<0.0001) and all genotypes and subtypes were detected. The HCV Ag and HCV RNA results agreed well for haemodialysis patients. Diagnostic specificity of HCV Ag was high (99.2%) considering HCV RNA as the reference. The two seronegative patients (of 2752) who were HCV RNA positive were also HCV Ag positive.

CONCLUSIONS

The ARCHITECT HCV Ag test is a reliable, highly specific assay for screening acute HCV infections in haemodialysis units. It is a robust alternative to HCV RNA testing.

Hepatitis C virus and kidney disease

Hepatitis C virus (HCV) infection remains frequent in patients on renal replacement therapy and has an adverse impact on survival in infected patients on chronic hemodialysis as well as renal transplant (RT) recipients. Nosocomial spread of HCV within dialysis units continues to occur. HCV is also implicated in the pathogenesis of renal dysfunction often mediated by cryoglobulins leading to chronic kidney disease as well as impairing renal allograft function. The role of antiviral therapy for hepatitis C in patients with renal failure remains unclear. Monotherapy with conventional interferon (IFN) for chronic hepatitis C is probably more effective in dialysis than in non-uraemic patients but tolerance is lower. Limited data only are available about monotherapy with pegylated interferon and combination therapy (pegylated IFN plus ribavirin) for chronic HCV in the dialysis population. Clinical experience with antiviral therapy for acute HCV in dialysis population is encouraging. Interferon remains contraindicated post-RT because of concerns about precipitating graft dysfunction. Sustained viral responses obtained by antiviral therapy in renal transplant candidates are durable after renal transplantation and may reduce HCV-related complications after RT (post-transplant diabetes mellitus, HCV-related glomerulonephritis, and chronic allograft nephropathy).