Hepatitis G virus infection in chronic dialysis patients and kidney transplant recipients.

BACKGROUND: The cloning of the hepatitis G virus (HGV), a novel RNA virus of the Flaviviridae family, has been very recently developed. HGV is known to be parenterally transmitted and has been detected in several patients with cryptogenic hepatitis. However, little information exists about the epidemiology of HGV infection in renal patients. We studied 178 chronic dialysis patients and 11 renal transplant individuals to evaluate prevalence, risk factors, and clinical manifestations of HGV infection in this population. METHODS: Hepatitis G virus infection has been detected by a modified PCR technology which incorporates digoxigenin-labelled nucleotides into the amplicon. Primers from the non-coding region and the NS-5 region of HGV are utilized for a single round amplification. Using a streptavidin surface and a biotin-labelled capture probe, the labelled nucleic acid is bound through the capture probe to the surface, and the amplified nucleic acid is detected using antibody to digoxigenin. RESULTS: HGV RNA was detected in 6% of chronic haemodialysis (HD) patients (11/172), 36% of renal transplant recipients (4/11), and 17% (1/6) of patients on peritoneal dialysis treatment (CAPD). There were no significant differences between HGV positive and negative patients on chronic HD treatment with regard to several demographic, biochemical and virological features. However, the frequency of anti-HCV antibody was significantly higher in HGV-positive than HGV-negative patients (9/11 (82%) vs 51/161 (32%), P = 0.006). In the whole group of HGV RNA-positive patients, 78% (11/14) had a history of blood transfusion requirements, 14/16 (87%) had co-infection with HCV, and 1 (6%) had co-infection with HBsAg. There was no significant association between HCV genotypes and HGV RNA positivity. Six (37.5%) of 16 HGV RNA-positive patients showed raised aminotransferase values in serum. CONCLUSIONS: Patients on maintenance dialysis and kidney transplant recipients are at increased risk of HGV infection; HGV is very frequently associated to hepatitis C co-infection, regardless of HCV genotype. HGV may be transmitted by blood transfusions but transmission routes other than transfusion are possible; 37.5% of HGV RNA-positive patients showed raised serum aminotransferase levels. Further investigations are necessary to clarify the role of HGV infection in the development of liver disease in this clinical setting.

Serologic survey for control of hepatitis C in haemodialysis patients: third-generation assays and analysis of costs.

There is little information about the serologic survey for control of hepatitis C by using third-generation assays among chronic haemodialysis (HD) patients, and no analysis of costs has been made to this end. A serologic survey for control of hepatitis C was performed in 190 HD patients attending a single dialysis unit, using second- and third-generation assays. Costs of both serologic surveys were calculated. Anti-HCV prevalence tested by third-generation assays increased from 25% (48/190) to 28% (53/190) compared to second-generation testing; 56% (9/16) of patients showing uncertain findings by second-generation tests gave unequivocal results by third-generation assays; median duration of HD treatment and raised aminotransferase levels were positively associated (P = 0.004 and P = 0.012, respectively) with anti-HCV detected by third-generation assays. The serologic survey for control of hepatitis C in HD patients at our centre was slightly more expensive by third-generation assays compared to second-generation testing (US$18866 vs US$17200 per year). In summary, the use of third-generation tests largely clarified the uncertain results of second-generation tests; new additional positive patients were detected by third-generation assays compared to second-generation testing. Third-generation assays showed the association of duration of HD treatment and raised aminotransferase levels with anti-HCV antibody, as previously found by first- and second-generation assays. To date, third-generation screening and confirmatory assays seem extremely useful in the serologic survey for control of hepatitis C in HD centres without a considerable outlay.

Hepatitis C virus genotypes in chronic dialysis patients.

BACKGROUND: Hepatitis C virus (HCV) infection is highly prevalent in dialysis patients. To further characterize HCV infection in this patient population, we studied the distribution of viral genotypes in 55 patients undergoing chronic dialysis treatment with seropositivity for HCV markers. METHODS: Thirty-two of 55 (58%) patients showed HCV RNA in the serum using reverse transcription polymerase chain reaction (RT-PCR) in the 5'-untranslated region (UTR) of the viral genome. HCV genotyping was performed using biotinylated type-specific oligonucleotide probes after hybridization with amplified sample material. RESULTS: HCV subtype 2a was dominant (56%), followed by HCV subtype 1b (31%), type 3 (3%) and 4 (3%). There was no association between demographic or clinical features of this cohort and HCV genotype. Genotype dependence was observed for antibody response toward the NS4 (c 100-3 and 5-1-1) proteins, which was infrequent in genotype 2a carriers compared with genotype 1b (p = 0.004). CONCLUSIONS: HCV subtype 2a was dominant in our cohort of anti-HCV-positive dialysis patients; there was no association between HCV genotypes and demographic or clinical features of patients; the absence of antibody response toward the NS4-related antigens was frequent in genotype 2a carriers and may serve to predict responses to interferon therapy. The relative homogeneity of the viral population in dialysis patients attending our unit suggests a nosocomial transmission of HCV in this clinical setting.

IgM antibody response to hepatitis C virus in end-stage renal disease.

BACKGROUND: In HBV infection, as in other viral diseases, antibodies of the IgM class are associated with acute or ongoing infection. In contrast, the significance of this antibody in HCV infection is unclear and data regarding end-stage renal disease (ESRD) patients are lacking. METHODS: We tested sera from 78 ESRD patients (66 chronic dialysis patients, 12 renal allograft recipients) showing anti-HCV IgG antibody, for serum anti-HCV IgM core antibody. A specific solid-phase enzyme-linked immunoassay (HCV IgM EIA, Abbot) was used. In all patients serum HCV RNA was detected by RT-PCR technique, with primers from the 5' untranslated region of the viral genome. RESULTS: Prevalence of anti-HCV IgM core antibody was 22% (17/78). We observed association between prevalence of anti-HCV IgM core antibody and frequency of HCV RNA in the serum. Thus 15 of 45 (33%) sera containing HCV RNA also contained anti-HCV IgM, while two of 33 (6%) HCV RNA negative sera showed anti-HCV IgM core antibody (P = 0.01). There was a significant relationship between absorbance values of anti-HCV IgM core antibody and NS3 (P = 0.01), NS5 (P = 0.04), and core (P = 0.0001) reactivity in RIBA-2 and RIBA-3 assays. Optical density values of anti-HCV IgM were significantly associated with the number of reactive bands in RIBA-2 (P = 0.04) and RIBA-3 (P = 0.03) assays. CONCLUSIONS: 22% of ESRD patients with anti-HCV IgG activity showed anti-HCV IgM core antibody in the serum. Anti-HCV IgM activity seems to correlate positively with HCV viraemia in ESRD population. Testing for this antibody may be useful as a serological marker to indicate the presence of ongoing HCV infection.

Virological and histological features of hepatitis C virus (HCV) infection in kidney transplant recipients.

BACKGROUND: Although there are some reports regarding prevalence of anti-HCV antibodies in kidney transplant patients, there are scarce data about viraemia, genotyping and liver histology of HCV infection in kidney transplant recipients. METHODS: We studied the prevalence of anti-HCV antibodies by second-generation screening and confirmatory assays in a cohort of 73 renal allograft recipients. All patients were tested for serum HCV RNA using reverse transcription polymerase chain reaction in the 5'-untranslated region (UTR) of the viral genome. HCV RNA positive patients were subjected to genotype analysis using biotinylated type-specific oligonucleotide probes after hybridization with amplified sample material. Eleven of 73 patients showing raised aminotransferase levels underwent hepatic biopsy. RESULTS: Fifteen of 73 (20%) patients were determined anti-HCV positive. Eleven of 73 (15%) showed detectable serum HCV RNA; no viraemic, seronegative patients were identified. Genotyping showed that HCV subtype 2a was dominant (64%), followed by HCV subtypes 1b (27%) and 1a (9%). Six of 11 (54%) HCV RNA patients and 12 of 62 (19%) HCV RNA negative patients showed raised aminotransferase levels (P = 0.03). Liver biopsies showed histological features of chronic hepatitis with mild or moderate degrees of activity. CONCLUSIONS: The prevalence of anti-HCV antibodies and HCV viraemia was 20% and 15% respectively; there was a good association between anti-HCV anti-bodies and HCV viraemia; hepatic enzyme levels were good indicators of ongoing HCV infection; HCV subtype 2a was prevalent; liver histology showed histological characteristics of chronic hepatitis with mild or moderate degrees of activity.

Recombinant hepatitis B vaccine use in chronic hemodialysis patients. Long-term evaluation and cost-effectiveness analysis.

The prevalence of hepatitis B virus (HBV) infection in our unit was 45% (86/190); there were 77 (40.5%) and 9 (4.7%) patients with previous and persistent HBV infection, respectively. Recombinant hepatitis B vaccine was given to 118 chronic HD patients with a regimen of 3 double doses administered intramuscularly at 0, 1 and 2 months, obtaining a seroprotection rate of 67% (79/118), 57% (45/79) being high responders. At month 24, 78% (40/51) maintained protective levels of anti-HBs, 45% (18/40) of them being high responders. There was a statistically significant difference between responder and non-responder patients with regard to nutritional parameters such as serum total proteins and mean levels of transferrinemia. The number of diabetic patients was significantly increased in the nonresponder group. Patients with persistent antibodies ('persistent responders') were younger and had a shorter duration of HD treatment compared to those responders who rapidly lost anti-HBs ('transient responders'). Serological positivity for antibodies against hepatitis B core antigen significantly facilitates the decrease of anti-HBs antibodies over time. We detected seven episodes of HBV infection among HD patients at our unit before the beginning of the vaccination program. On the contrary, there were no episodes of HBV infection among responder vaccinees during the 24-month follow-up period. After the initial cost of vaccination, a savings of US$ 3,272 per year was realized by the elimination of frequent serologic screening of vaccine responders.

Virological characteristics of hepatitis C virus infection in chronic hemodialysis patients: a cross-sectional study.

Detection of hepatitis C virus viremia (HCV RNA) in serum of hemodialysis (HD) patients is crucial for documenting ongoing infection because the clinical and epidemiological importance of anti-HCV positivity is not clear. HCV viremia was studied in 104 HD patients by reverse transcription polymerase chain reaction (RT PCR) using primers localized in the 5' non-coding region of the viral genome. We used two different methods to detect HCV RNA: a direct PCR amplification of HCV RNA from human serum, and a standard RT PCR procedure (requiring the RNA extraction step). There were 50 (48%) anti-HCV positive patients in this population. Twenty-two (21.1%) out of 104 patients showed HCV RNA in serum by standard RT PCR technique: they belonged to the anti-HCV positive patient group, whereas all anti-HCV negative patients were HCV RNA negative. Prevalence of HCV RNA was more than doubled when standard RT PCR was used compared to direct RT PCR protocol. There was a good association between serum HCV RNA and circulating anti-HCV antibodies, tested by second-generation ELISA and RIBA assays. HCV viremia was not associated with either the presence or the absence of a particular RIBA antibody specificity. AST and ALT levels had no predictive value for HCV viremia, because they were repeatedly normal in the majority of viremic patients (16/22: 73%).(ABSTRACT TRUNCATED AT 250 WORDS)

Comparison of second-generation screening and confirmatory assays with recombinant antigens and synthetic peptides against antibodies to hepatitis C virus: a study in renal patients.

The aim of this study was to compare some common tests which are nowadays routinely used to screen and to confirm anti-HCV antibodies in renal patients. There was agreement between Ortho 2 and Abbott 2 in 94% of samples; structural and nonstructural beads of the Abbott supplementary assay were in agreement with 4-RIBA in 98 and in 85% of samples, respectively; 61% of Ortho 2 samples and 65% of Abbott 2 samples were confirmed by 4-RIBA; there was a correlation between semiquantitative analysis of screening tests (Ortho 2 and Abbott 2) and positive results by 4-RIBA; 36 and 33% of Ortho-2- and Abbott-2-positive samples were 4-RIBA indeterminate: in these instances more sophisticated techniques (polymerase chain reaction) (PCR) could be useful as a third-level assay. The comparison between Ortho 2, based on recombinant antigens, and Innotest, based on synthetic peptides, showed agreement only in 44% of samples, but this preliminary comparison cannot afford definitive conclusions. These findings suggest that second-generation assays may sometimes yield conflicting results in renal patients. These contradictions will be resolved by new HCV tests or PCR.

Incidence of seroconversion for hepatitis C virus in chronic haemodialysis patients: a prospective study.

We conducted a prospective study in HD patients of our unit to evaluate the incidence of seroconversion for HCV in this high-risk group. Two hundred and thirty-five patients were observed during the average follow-up of 29.4 months: 183 were seronegative and 52 seropositive for anti-HCV antibodies at the start of the study. During the observation period two of 183 patients developed anti-HCV antibodies late in the study, while the other 181 patients remained seronegative throughout the observation period; anti-HCV antibodies persisted through the follow-up in the 52 HCV-positive patients at the beginning of the study. Our results showed a very low incidence of HCV seropositivity (0.44% per year) after implementation of our operative protocol including 'universal precautions' and other infection control procedures. Once infected, there is no disappearance rate of anti-HCV. The 4-RIBA results did not change during the follow-up period. Prevalence of HCV RNA by PCR technique was 41% (22 of 54) among anti-HCV-positive patients. Future investigations are warranted to clarify the exact route of transmission of HCV among HD patients and to reduce the rate of HCV transmission in this clinical setting.

Antibodies to hepatitis C virus (HCV) in chronic renal failure (CRF) patients on conservative therapy: prevalence, risk factors and relationship to liver disease.

There are no data regarding HCV prevalence in CRF patients not requiring dialysis. In order to assess prevalence and risk factors for HCV infection in CRF patients on conservative therapy we tested, by second-generation assays such as Ortho 2 and 4-RIBA, 221 predialysis CRF patients attending our Department. Forty-four (20%) patients were anti-HCV positive. Anti-HCV positivity was related to blood transfusion requirement, past or current elevations of transaminase levels and, to a lesser degree, CRF duration. The prevalence of anti-HCV positivity among CRF patients who were never transfused was about 10 times higher than that of blood donors. Our data show that predialysis CRF patients should be considered a specific risk group for HCV infection; blood transfusion history and duration of CRF are risk factors for acquisition of HCV infection; HCV infection may play a role in the development of liver disease in this clinical setting.

Antibodies to hepatitis C virus (HCV) and transaminase concentration in chronic haemodialysis patients: a study with second-generation assays.

We used first- and second-generation assays such as Ortho 1, Ortho 2 and 4-RIBA to define prevalence and risk factors for anti-HCV antibodies in haemodialysed patients. Forty-nine (24%) subjects were found to be anti-HCV positive. Anti-HCV positivity was related to duration of dialysis and past or current elevations of GOT and GPT; the frequency of transfused patients was greater in HCV-positive than in HCV-negative subjects; there were 31 patients (prevalence of 20%) with anti-HCV antibodies among non-transfused patients. These findings show that, tested by second-generation assays, HCV infection is detected more than twice as commonly in haemodialysis patients and may be responsible for a significant proportion of liver disease in this clinical setting. Acquisition of hepatitis C virus by dialysis patients is not only through blood transfusions but also secondary to hepatitis C virus presence within the unit itself.