New insights into hepatitis C virus infection of hemodialysis patients: the implications

Hepatitis C infected hemodialysis and renal transplant patients with elevated α-glutathione S-transferase have increased risk for liver damage

Patients on hemodialysis (HD) and renal transplant recipients (RT) have a high prevalence of HCV infection. Theaimof our study was to determine the prevalence of HCV-RNA in the anti-HCV positive patients and to compare the biochemical parameters of PCR(+) and PCR(−) subgroups.Methods:The 525 sera were screened for anti-HCV. HCV-RNA was detected by polymerase chain reaction (PCR) and liver enzymes [SGOT, SGPT, GGT,α-glutathione S-transferase (GST)] were measured.Results:Active viraemia was found only in 187 of 289 (65%) seropositive HD patients in contrast to 53 of 53 (100%) of seropositive RT patients. Significantly increased (p<0.05) GST values (9.9 μg/l) were found in the PCR(+) subgroups compared to GST levels (2.7 μg/l) of the PCR(−) subgroups. Elevated GST concentration was found in 80% (208/251) of PCR(+) patients. The measured enzymes were not elevated in HCV infected patients. Six percent of HD and 11% of RT patients were screened before seroconversion. Diagnostic sensitivity (80%) and specificity (79%) of GST were calculated as good for early liver damage caused by HCV. In contrast, the sensitivity of the measurement of other liver enzymes were very weak (SGOT: 8%; SGPT: 10%; GGT: 42%).Conclusion:The significantly higher viraemia of the RT subgroup could be related to the immunosuppressive therapy. Increased GST level may be a useful indicator of tissue damage during HCV infection. If HCV infection is suspected, PCR and GST measurement should be performed, even if anti-HCV result is negative.

Hepatitis C virus infection in haemodialysis: the 'no-isolation' policy should not be generalized

Hepatitis C virus (HCV) infection is the most common blood-borne viral infection in haemodialysis. It causes significant morbidity and long-term mortality. Practice of universal precautions has been reported to be sufficient to prevent HCV seroconversion in dialysis units. However, the seroconversion rate remains very high in many dialysis units. A previous study from 1995 to 1998 at our own hospital without isolation showed that nosocomial transmission is the major cause of HCV seroconversion. The present study was therefore conducted with the aim to study the impact of isolation on HCV seroconversion. In this prospective cohort study, with non-probability consecutive sampling, patients with HCV infection were dialysed in an isolated room. In addition, standard universal precautions were practiced. HCV seroconversion rate was compared with the previous study. All patients with end-stage kidney disease (ESKD) admitted to our hospital for renal replacement therapy were included in the present study. At the time of admission, HCV screening was done. All anti-HCV-positive patients were dialysed in an isolated room. While on maintenance haemodialysis, all patients were monthly tested for anti-HCV, aspartate aminotransferase and alanine aminotransferase. Any patient who had HCV seroconversion was transferred to an isolated room for maintenance haemodialysis. Patients with HCV infection were managed by further testing for HCV-RNA and liver biopsy. Every patient who ultimately received renal transplantation at our hospital was also tested for HCV just prior to renal transplantation as well as 3 months after renal transplantation. HCV infection was diagnosed by detecting anti-HCV antibodies using an ELISA-based third-generation diagnostic test kit. Serum bilirubin, aspartate aminotransferase and alanine aminotransferase were assayed using standard laboratory techniques. From March 2003 to February 2006, 1,417 patients were admitted for haemodialysis in our unit. Of these 1,077 (76%) had ESKD. Mean age of patients was 42.47 +/- 16.2 (14-94) and 70.39% were males. Patients with ESKD had had more dialysis sessions (10.9 +/- 39.5 vs. 4.4 +/- 5.95, p = 0.009), more blood transfusions and more pre-existing HCV infections (4.72 vs. 1.5%, p = 0.009) than patients with acute renal failure. Of the ESKD patients, 65.7% were discharged, 9.47% died, 1.85% were shifted to chronic ambulatory peritoneal dialysis and 22.46% patients received renal transplantation. Of the patients who received renal transplantation, HCV seroconversion was detected in 2.75%. In the previous study without isolation practices, the HCV seroconversion rate in transplanted patients was 36.2%. The hazard of HCV seroconversion was 0.97 (95% CI 0.93-1.02, p = 0.2) for each additional dialysis and 1.09 (95% CI 0.88-1.36, p = 0.37) for each additional blood transfusion. The study concludes that isolation of HCV-infected patients during haemodialysis significantly decreases the HCV seroconversion rate.

Percutaneous liver biopsy is safe in chronic hepatitis C patients with end-stage renal disease

BACKGROUND & AIMS

Liver biopsy is useful for staging fibrosis in chronic hepatitis C (CHC) patients with end-stage renal disease (ESRD) to determine renal transplant eligibility and to make CHC treatment decisions. There is concern about an increased risk associated with percutaneous liver biopsy (PCNB) in ESRD patients. We compared the safety of PCNB in CHC patients with and without ESRD.

METHODS

We reviewed PCNBs performed between 1996 and 2004 for technique, histology, and complications in 78 ESRD patients with CHC and in 241 control patients with CHC and no renal failure, randomly matched for age, sex, and race. Platelet counts, prothrombin, and partial thromboplastin times, but not bleeding times, were checked before biopsy. Deamino-8-D-arginine vasopressin was not given before the biopsy.

RESULTS

The mean age of the patients was 50 years; 72% were male, 97% were African American, and 3% were Caucasian. The control group had a significantly higher proportion of patients with advanced fibrosis (P < .04). Only 1 patient with ESRD (1.3%) developed a moderate complication. Five controls (2.1%) developed complications, 3 of which were severe.

CONCLUSIONS

Severe complications after PCNB are uncommon, and patients with ESRD and CHC are at no increased risk. Testing for bleeding time and the routine use of deamino-8-D-arginine vasopressin are not necessary before PCNB in patients with ESRD.

Efficacy and Safety of Intravenous Iron Therapy for HCV-Positive Haemodialysis Patients

BACKGROUND

Iron supplementation is the cornerstone of anaemia management in haemodialysis (HD) patients. However, efficacy and safety of intravenous (IV) iron therapy in hepatitis C virus (HCV)-positive HD patients is yet to be elucidated.

METHODS

Sixty-six maintenance HD patients with suboptimal response to recombinant human erythropoietin (rh-EPO) were administered IV iron. Each patient received 100 mg/session IV iron sucrose for ten consecutive HD sessions and then the dose was decreased to 50-100 mg weekly or biweekly. Patients were followed for haemoglobin (Hb), ferritin, rh-EPO dose requirements, transaminase levels, and adverse drug reactions.

RESULTS

Baseline demographic and clinical characteristics, as well as Hb, ferritin, transaminase levels, rh-EPO and iron doses were similar between HCV-positive (n = 32) and HCV-negative patients (n = 29). After 5 months of follow-up, a significant increase in ferritin and Hb levels and decrease in rh-EPO doses were observed in both groups. The incidence of adverse drug reactions was not associated with HCV serology. Significant elevation in both alanine and aspartate aminotransferase levels were detected in HCV-positive patients.

CONCLUSION

This study has shown that IV iron administration reverses suboptimal response to rh-EPO administration in HD patients regardless of HCV serology. There is however subtle increase of transaminase levels in HCV-positive patients. Further studies are warranted to reveal the impact of variation in serum transaminase levels during IV iron administration in HCV-positive HD patients.

Investigation of possible clinical and laboratory predictors of liver fibrosis in hemodialysis patients infected with hepatitis C virus

Hepatitis C virus (HCV) infection is common in patients with end-stage renal disease. The severity of liver damage, including fibrosis, in these cases varies widely. Although many investigators have searched for noninvasive alternatives to liver biopsy for evaluating the extent of liver fibrosis, no useful noninvasive predictors have been found. Currently, liver biopsy is essential to assess the degree of fibrosis. The aim of this retrospective study was to investigate a range of clinical and laboratory parameters in HCV-infected hemodialysis (HD) patients and identify possible predictors of fibrosis. Ninety-five consecutive HD patients with HCV infection underwent liver biopsy. Each specimen was evaluated for fibrosis stage. Correlations were sought between the degree of fibrosis and the age, HD duration, time since first possible HCV exposure, body mass index, HCV RNA titer, serum ferritin level, and serum alanine aminotransferase (ALT) level. The analysis revealed no significant correlations between fibrosis stage and the parameters investigated (mean age: r =.017, P =.89; mean HD duration: r =.066, P =.576; body mass index r =.231, P =.152; HCV RNA titer: r =.015, P =.091; serum ferritin: r =.134, P =.32; serum ALT r =.108, P =.927). Links with serum ALT were reevaluated with upper normal levels arbitrarily set at 30 IU/L and 20 IU/L, but these analyses also revealed no correlations between fibrosis stage and ALT level (P =.98 and P =.449, respectively). Therefore liver biopsy is still essential for accurate assessment of liver pathology in HD patients with HCV.

Prospective study of hepatitis C virus infection in hemodialysis patients by monthly analysis of HCV RNA and antibodies

The aims of this study were to (i) evaluate the prevalence and the incidence of hepatitis C virus (HCV) infection in hemodialysis patients in two different centers in São Paulo (Brazil), (ii) determine the time required to detect HCV infection among these patients by serology or PCR, (iii) establish the importance of alanine aminotransferase determination as a marker of HCV infection, and (iv) identify the HCV genotypes in this population. Serum samples were collected monthly for 1 year from 281 patients admitted to hospital for hemodialysis. Out of 281 patients, 41 patients (14.6%) were HCV positive; six patients seroconverted during this study (incidence = 3.1/1000 person-month). In 1.8% (5/281) of cases, RNA was detected before the appearance of antibodies (up to 5 months), and in 1.1% (3/281) of cases, RNA was the unique marker of HCV infection. The genotypes found were 1a, 1b, 3a, and 4a. The presence of genotype 4a is noteworthy, since it is a rare genotype in Brazil. These data pointed out the high prevalence and incidence of HCV infection at hemodialysis centers in Brazil and showed that routine PCR is fundamental for improving the detection of HCV carriers among patients undergoing hemodialysis.

Hepatitis C screening strategies in hemodialysis patients

Hepatitis C virus (HCV) infection is common in patients undergoing chronic hemodialysis, with an estimated yearly incidence of 0.2% and prevalence between 8% and 10%. Although a screening strategy based on alanine aminotransferase (ALT) values is currently recommended, this strategy has not been evaluated for cost-effectiveness compared with other potential screening strategies. A comparison therefore was made using a decision-analysis model of a simulated cohort of 5,000 hemodialysis patients followed up for 5 years. Using direct medical costs, three strategies were evaluated, including: (1) ALT values with confirmatory testing (biochemical), (2) serial enzyme-linked immunosorbent and strip immunoblot assay testing (serological), and (3) polymerase chain reaction (viral). Under baseline assumptions, the per-patient cost of screening hemodialysis patients for HCV was $378 for biochemical-based testing, $195 for serological-based testing, and $696 for viral-based testing. Our model was robust when varying the costs of testing, as well as the incidence and prevalence of HCV infection. Results of sensitivity analysis by varying costs, HCV incidence, and HCV prevalence indicated that serological-based screening was less costly than biochemical testing. Biochemical testing was in turn less costly than viral-based screening. Serological-based testing was also more effective in the diagnosis of de novo HCV infection, with a likelihood ratio of 85, in contrast to the likelihood ratio of 44 with biochemical-based testing using viral-based screening as the gold standard. A serological-based screening strategy is less costly and more effective than biochemical-based screening in the diagnosis of de novo HCV infection. Serological-based screening should be considered for HCV screening in hemodialysis populations.

Chronic hepatitis C infection in patients with end stage renal disease: characterization of liver histology and viral load in patients awaiting renal transplantation

OBJECTIVES

Hepatitis C virus (HCV) is common in patients with end stage renal disease (ESRD) awaiting renal transplantation (RT). However, few data are available on the liver histology and viral titer in these patients relative to patients with HCV and normal renal function. The aims of this study were to assess liver histology, quantitative HCV-RNA titer, and alanine aminotransferase (ALT) levels in patients with ESRD awaiting RT, and to identify clinical predictors of histological progression to advanced bridging fibrosis and/or cirrhosis.

METHODS

A total of 50 consecutive patients (mean age 42 yr, 62% male) with ESRD and HCV, who were awaiting RT, underwent liver biopsy. Two HCV populations, one with persistently normal ALT and another with elevated ALT, both with normal renal function, served as controls. HCV-RNA titer was assessed by quantitative PCR.

RESULTS

Of the patients with ESRD, 94% had normal ALT. Log HCV RNA titer was significantly higher in patients with ESRD (5.8+/-0.3) than in either normal ALT (5.4+/-0.1) or elevated ALT (5.3+/-0.1) controls (p < 0.05). Knodell Histological Activity Index (HAI) in patients with ESRD was similar to that observed in control patients with normal ALT (4.8+/-0.4 vs 4.9+/-0.4) but significantly less (p < 0.05) than that observed in control patients with elevated ALT (8.4+/-0.5). The percentage of patients with bridging fibrosis or cirrhosis was similar in patients with ESRD and controls with persistently normal ALT (22% vs 13%) but significantly less (p < 0.001) than that observed in control patients with elevated ALT (48%). No significant differences in ALT, HCV-RNA titer, duration on hemodialysis, or time from first possible exposure was observed between ESRD patients with advance fibrosis (n = 11) and those with mild disease (n = 39).

CONCLUSIONS

Our data suggest that liver biopsy is necessary to exclude significant liver pathology in patients with HCV and ESRD, and to help define those patients in whom interferon treatment might be helpful.

Interferon-alpha in chronic hepatitis C infection in dialysis patients

This study assesses the efficacy and adverse effects of interferon-alpha (IFN-alpha) administered at a dosage of 3 million units three times weekly for 1 year in 17 hemodialysis patients with hepatitic C virus (HCV)-associated chronic hepatitis (biopsy proven). The patients were prospectively followed up for a period of 18 months. Liver biopsy was repeated after 6 months of treatment in 13 patients. Patients were classified according to the histological activity index. Biochemical and virological responses were evaluated at the end (end-of-treatment response) and 6 months after completion of therapy (sustained response). HCV RNA became negative in 76% of the patients after 12 weeks of treatment, in 88% after 12 months of treatment, and in 71% of the patients 6 months after completion of therapy. HCV genotype 4 was found in 60% of our population. Alanine aminotransferase (ALT) levels were initially increased in only 6 patients and normalized in 4 of these patients after 12 weeks of therapy, with end-of-treatment and sustained biochemical responses of 83% and 67%, respectively. Of 13 patients who underwent liver biopsies after 6 months of therapy, 11 patients (85%) showed histological improvement. One patient could not tolerate therapy because of marked lethargy and myalgia; the other patients had minor side effects that did not require discontinuation of treatment. Two patients received a cadaveric renal transplant after 1 year of IFN treatment, and they continued to maintain biochemical and virological responses after a follow-up of 17 and 28 months, respectively.

Detection of anti-hepatitis C virus antibodies in patients undergoing dialysis by utilizing a hepatitis C virus 3.0 assay: correlation with hepatitis C virus RNA

Hepatitis C virus (HCV) infection is endemic in long-term dialysis units. We assessed the performance of a recently developed HCV 3.0 assay for the detection of HCV antibodies in patients undergoing dialysis. The study evaluated 128 patients undergoing long-term maintenance hemodialysis. Anti-HCV was detected by 2.0 and 3.0 enzyme immunoassay (EIA). Results were confirmed with recombinant immunoblot assays (RIBA 2.0 and RIBA 3.0). HCV RNA was detected by using reverse transcriptase-polymerase chain reaction (RT-PCR). Thirty-two patients (25%) were HCV EIA 2.0 positive. Of these, 1 was RIBA 2.0 negative (PCR positive), 3 were indeterminate (3 PCR positive), and 28 were positive (23 PCR positive). Thirty-five (27%) were HCV EIA 3.0 positive. One was RIBA 3.0 negative (PCR positive), 1 was indeterminate (c33c, PCR positive), and 33 were positive (27 PCR positive) by RIBA 3.0. Thus only 1 PCR-positive patient was negative with RIBA 2.0 and 3.0 assays. Two of the 3 RIBA 2.0 indeterminate samples were positive with RIBA 3.0. One remained indeterminate but was HCV RNA positive. In summary, HCV 3.0 EIA detected 4 additional viremic patients but was positive in 6 PCR-negative subjects. A high correlation of the presence of antibody to c33c with HCV RNA (28 of 34, 82%) was found, and it was found in all anti-HCV positive samples and in 1 indeterminate sample. We conclude that the HCV EIA 3.0 test with the supplemental confirmatory RIBA 3.0 test may improve the sensitivity for the detection of anti-HCV. Nevertheless, in potentially immunocompromised patients undergoing dialysis, PCR continues to be the only reliable test for detecting viremia.

Universal precautions prevent hepatitis C virus transmission: a 54 month follow-up of the Belgian Multicenter Study. The Universitaires Cliniques St-Luc (UCL) Collaborative Group

The isolation of anti-hepatitis C virus (HCV) in hemodialyzed (HD) patients has been repeatedly advocated to prevent nosocomial HCV transmission. We evaluated the incidence of seroconversion for HCV in Belgian HD patients, and demonstrate the complete prevention of HCV transmission by adherence to the universal precautions advocated by the Centers for Disease Control (Atlanta, GA, USA). All (N = 963) HD patients from 15 units, none of which isolates anti-HCV positive patients, were tested by a second or third generation enzyme-linked immunosorbent assay (with confirmation by a second- or third-generation recombinant immunoblot assay or the polymerase chain reaction) every 18 months from May 1991 to November 1995. Follow-up was available in 488 patients (drop-outs resulting from death or transplantation mainly). The yearly incidence of seroconversion for HCV over the initial 18 months was 1.41%, with evidence suggestive of nosocomial HCV transmission. Universal precautions were therefore reinforced. The incidence of seroconversion subsequently fell to 0.56% and 0%, respectively (P = 0.014), despite the facts that the average transfusion load and the proportion of patients with dialyzer reuse or with monitors disinfected after each session did not change significantly. We conclude that the strict enforcement of universal precautions fully prevents HCV transmission to HD patients. The isolation of anti-HCV positive patients is not warranted.

Acute hepatitis C among renal failure patients on chronic haemodialysis

Hepatitis C virus (HCV) infection is common in haemodialysis units, yet little information is available about the clinical feature of acute hepatitis C among renal failure patients. The present study is based on 49 cases of acute hepatitis C seen at a haemodialysis centre where sporadic nosocomial infection was occurring up to June 1993. Liver function tests were done at 4 weekly intervals on all dialysis patients, anti-HCV antibodies were tested by the C-100 and second generation tests and serum HCV-RNA was determined by the branched DNA and Amplicore tests. Diagnosis of acute hepatitis C was made on the basis of an acute rise in alanine aminotransferase (ALT) and seroconversion to positive anti-HCV antibodies. Clinical presentation of acute hepatitis was generally mild with rare overt jaundice and the diagnosis was possible only from increased ALT, which was generally low. Spontaneous resolution of acute hepatitis within 8 months with clearance of viral RNA occurred in only four cases, 91.8% of patients developing chronic hepatitis. Biopsy in 12 cases with high ALT levels showed mild to moderate inflammatory activities. In conclusion, the clinical presentation of acute hepatitis C is generally mild in chronic haemodialysis patients, but spontaneous resolution is infrequent. A longer follow-up period is required for defining the long-term prognosis.

Serologic responses to hepatitis C virus in solid organ transplant recipients

BACKGROUND

Hepatitis C (HCV) infection is known to have been transmitted by both blood transfusion and donor organs. We sought to determine the historical incidence of donor- and transfusion-acquired HCV infection in kidney transplant (RTx) and heart transplant (HTx) recipients at our center and to study the kinetics of seroconversion to HCV.

METHODS

A bank of sera collected from organ donors (388 RTx and 88 HTx) who received allografts between January 1984 and April 1992 was screened for anti-HCV using a third generation enzyme immunoassay. Recipient sera collected before transplant (preTx), at 1 year after transplant, and at last follow-up were tested. Fresh follow-up sera on all surviving anti-HCV-positive (+) RTx and HTx, all anti-HCV-negative (-) HTx, and a subset of 85 anti-HCV- RTx were assayed for HCV RNA using an reverse transcriptase-polymerase chain reaction assay.

RESULTS

Twenty-four of 388 RTx (6.2%) and 2 of 88 HTx (2.3%) were anti-HCV+ preTx. Eight of 218 (3.7%) organ donors were anti-HCV+. Six of the seven (85.7%) anti-HCV+ donors with adequate recipient follow-up transmitted HCV infection to one or more recipients. Nineteen of 313 RTx (6.1%) and 8 of 72 HTx (11.1%) with follow-up > or =1 year seroconverted to anti-HCV. One of 85 (1.2%) anti-HCV- RTx and 3 of 44 (6.8%) anti-HCV-HTx were HCV RNA+ when tested at last follow-up. Five cases of de novo HCV infection occurred after the introduction of first generation anti-HCV screening of donors. Persistent viremia (HCV RNA+) at last follow-up was observed in 70.6% (12/17) RTx anti-HCV+ preTx. Fourteen of 15 (93.3%) RTx and 9 of 9 (100%) HTx with de novo HCV infection had persistent viremia. Seroconversion was more delayed in HTx than RTx (P=0.0572, log-rank Mantel-Cox statistic) although both groups demonstrated an impaired humoral response to HCV when compared with the immunocompetent host.

CONCLUSIONS

Organ donor- and transfusion-acquired HCV infection was common in RTx and HTx transplanted before the introduction of second generation anti-HCV screening in 1992. Serologic responses to HCV are often delayed and sometimes absent in these patients. Assays for HCV RNA should be considered as a screening test for the detection of HCV infection in this population. Serologic responses to HCV were more impaired in HTx compared with RTx, which may reflect the more intensive immunosuppressive regimens given to HTx at our center.

Serological diagnosis of hepatitis C virus in patients with liver disease in Saudi Arabia. Evaluation of antibody determination by recombinant immunoblot assays in relation to RNA detection by polymerase chain reaction

Sera from 164 Saudi Arabian patients with non-A, non-B hepatitis liver disease were examined for antibodies to hepatitis C virus (HCV) by second- and third-generation recombinant immunoblot assay (RIBA-2 and RIBA-3) and for HCV RNA by polymerase chain reaction (PCR). By using RIBA-2, 92 (56.1%) were reactive, 64 (39%) were nonreactive, and 8 (4.9%) were indeterminate. By using RIBA-3, 98 (59.7%) were reactive 60 (36.6%) were nonreactive, and 6 (3.7%) were indeterminate. By using PCR, 108 (65.9%) were positive. Of the eight RIBA-2 indeterminate samples, seven became RIBA-3 reactive but PCR-positive, and one became RIBA-3 nonreactive but PCR-negative. Of the six RIBA-3 indeterminate samples, five were RIBA-2 nonreactive but PCR-positive, and one was RIBA-2 reactive but PCR-negative. From our study on Saudi patients, we conclude that RIBA-3 has slightly but not significantly improved the results of anti-HCV antibody detection, and is probably of more value to resolve those indeterminate samples by RIBA-2. Although expensive, PCR remains the most reliable HCV diagnostic method until an HCV antigen detection test is available.

Undiagnosed hepatitis C virus infection in hemodialysis patients: value of HCV RNA and liver enzyme levels

At present, routine screening for hepatitis C virus (HCV) infection is based on the detection of antiviral antibodies. Underdiagnosis of HCV infection by using HCV antibody tests, however, still occurs. Additional diagnostic means are provided by the polymerase chain reaction (PCR). The measurement of aminotransferase (ASAT and ALAT) has served as an auxiliary, less specific test. The present research aimed to design practical and low cost strategies to diminish underdiagnosis of HCV infection in dialysis patients. With this purpose in mind, we examined whether aminotransferases values in HCV antibody-negative patients could be related to undiagnosed HCV infection, by using HCV RNA testing by PCR as the gold standard. In 112 hemodialysis patients, we found 78 negative and 34 positive for HCV antibodies. A major finding was that 222 (28.2%) out of the 78 HCV antibodies-negative patients had positive HCV RNA by PCR. In repeated samples taken at six months follow-up from 19 out of these 22 patients, only one of them was positive for anti-HCV antibodies; moreover, a positive HCV RNA by PCR was confirmed in 13 (68.5%) of them. Within the HCV antibody-negative group, the mean values of ASAT, ALAT and gammaglutamiltransferase were higher (P < 0.001, P < 0.001 and P < 0.02, respectively) in the HCV PCR-positive versus the HCV PCR-negative patients. No significant differences were found in the liver enzyme values between the HCV antibody-negative, HCV RNA positive and the HCV antibody positive, HCV RNA positive individuals. Histological samples from two HCV RNA positive, HCV antibody-negative patients disclosed the presence of a mild liver disease. In conclusion, the present study demonstrates the critical importance of HCV RNA determination by PCR in hemodialysis patients who have no detectable circulating antibodies against the HCV. Furthermore, in conditions in which PCR technology is not readily available, we have established that the existence of a moderate increase of aminotransferases is a helpful clue to detect patients with absent HCV antibodies, and might represent an useful, low cost tool for HCV screening in dialysis patients.