Single-tube reverse transcription and heminested polymerase chain reaction of hepatitis C virus RNA to detect viremia in serologically negative hemodialysis patients

Hepatitis C virus screening and management of seroconversions in hemodialysis facilities

Over the past two decades, healthcare-associated exposure has increasingly been proved to be a means of hepatitis C virus (HCV) transmission, especially in hemodialysis facilities. The prevalence of HCV among hemodialysis patients is known to be several times greater than that of the general population of the United States, and chronic HCV infection is associated with significant morbidity and mortality among these patients. During 2008-2011, HCV infection outbreaks were identified in multiple US hemodialysis facilities, resulting in at least 46 new HCV infections among hemodialysis patients. These outbreaks, linked to infection control breaches, also highlight the failure of some facilities to follow established guidelines for routine HCV antibody (anti-HCV) screening and response to new HCV infection among hemodialysis patients. Current national guidelines recommend screening of hemodialysis patients for anti-HCV on facility admission and, for susceptible patients, on a semiannual basis. Here, we seek to underscore the importance of compliance with national recommendations for anti-HCV screening of hemodialysis patients and actions to be taken in the event of possible HCV transmission within a hemodialysis facility. These include general steps to ensure that: hemodialysis patients are routinely screened for anti-HCV to facilitate early detection of new infections; newly infected patients are informed of the change in their HCV status and undergo clinical evaluation; and public health officials are notified of new HCV infections in a timely manner. We then focus on the need to assess infection control practices at the facility, with particular attention given to safe handling of injectable medications, hand hygiene and disinfection practices. In the absence of a vaccine, routine screening and adherence to standard infection control practices will remain the key strategies for preventing HCV transmission in hemodialysis units.

Development of an HCV infection risk stratification algorithm for patients on chronic hemodialysis

OBJECTIVE

The prevalence of hepatitis C virus (HCV) in patients on chronic hemodialysis (HD) is near 9%. Transaminases, which are lower in HD patients, are not effective in screening for HCV. Our aim was to design an HCV risk stratification strategy incorporating lowered aminotransferase levels and other clinical parameters.

METHODS

Patient serum from 168 consecutive HD patients was analyzed for AST, ALT, ferritin, and hepatitis C antibody. Sensitivity, specificity, positive predictive value, and negative predictive value were calculated for lower transaminase values. Multivariate classification and regression tree analysis was used to determine the best combination of variables to predict risk for HCV infection.

RESULTS

Median AST and ALT levels were higher in anti-HCV Ab(+) patients (p < 0.05). Applying a lower cutoff value for ALT of 16 IU/L resulted in a sensitivity of 61.1%, a specificity of 66.7%, a positive predictive value of 33.9%, and a negative predictive value of 86.0% for detection of HCV infection. Multivariate classification and regression tree analysis derived an algorithm using patient age, months on HD, and AST, resulting in a 97.2% sensitivity and a 51.9% specificity for the detection of HCV(+) HD patients.

CONCLUSIONS

A lower normal cutoff value of 18 IU/L for AST and 16 IU/L for ALT increased sensitivity and specificity for the detection of HCV infection in HD patients. An algorithm combining lower transaminases with clinical parameters improved both sensitivity and specificity in HCV detection. Prospective confirmation of this algorithm would allow more selective HCV enzyme immunoassay and polymerase chain reaction testing in dialysis units.

High prevalence of the His63Asp HFE mutation in Italian patients with porphyria cutanea tarda

Sporadic porphyria cutanea tarda (PCT) is caused by a reduced activity of uroporphyrinogen decarboxylase (URO-D) in the liver. Mild to moderate iron overload is common in PCT, as iron is one of the factors which trigger the clinical manifestations of the disease through the inactivation of URO-D. A role for genetic hemochromatosis in the development of iron overload in sporadic PCT has been hypothesized in the past. The aim of this work was to investigate whether mutations of HFE, which is a candidate gene for hemochromatosis, play the role of genetic susceptibility factors for PCT in Italian patients, who have a high prevalence of acquired triggering factors, such as hepatitis C virus (HCV) chronic infection and alcohol. We determined HFE genotypes of 68 male patients with PCT. Our data do not confirm an association of PCT with the Cys282Tyr HFE mutation, strongly associated with hemochromatosis in Northern European countries. A second mutation of HFE, His63Asp, however, had a significantly increased frequency as it was present in half of the patients. Surprisingly, the presence of the His63Asp mutation was not related to the iron status of patients, suggesting that a subtle abnormality of iron metabolism induced by this mutation could escape detection by the standard parameters of iron status. In PCT patients with liver disease, the presence of the mutation could contribute to the inactivation of URO-D, either directly or through a synergistic action with other factors that cause liver damage.

Hepatitis G virus infection in hemodialysis patients

The increased risk of hemodialysis patients for infections sustained by hepatitis viruses is likely to extend to a newly discovered parenterally transmitted virus, HGBV-C/HGV, able to cause acute and chronic hepatitis. The aim of this study was to assess the prevalence and clinical relevance of this infection in Italian hemodialysis patients. Nineteen of 100 patients (19%) on maintenance hemodialysis were viremic for HGBV-C/HGV, and all of them were infected with a HGV-like genotype. Eight of these patients were coinfected by hepatitis B or hepatitis C viruses. A clinical picture of chronic hepatitis was not appreciable in patients with isolated HGV infection and the presence of HGV did not appear to modify the clinical course of hepatitis B and hepatitis C infections.

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.

Iron stores, response to alpha-interferon therapy, and effects of iron depletion in chronic hepatitis C

We studied 81 patients with chronic hepatitis C to investigate the relationship between iron and alpha-interferon response. Sixty-one patients (group A) were given alpha-interferon irrespective of iron status, whereas 20 (group B) with iron overload, were iron depleted before alpha-interferon therapy. In group A, 21 patients responded to alpha-interferon and 40 were non-responders. Increased iron indices were significantly more frequent in non-responders than responders. Multivariate analysis showed that among the independent variables evaluated, only gamma-GT and liver iron concentration predicted therapy outcome. After phlebotomy treatment, serum alanine aminotransferase fell significantly both in patients of group B (196 +/- 122 IU/l vs 82 +/- 37 IU/l, p < 10(-6)) and in 12 non-responders of group A (198 +/- 89 IU/l vs 107 +/- 81 IU/l, p < 10(-6)). In 16 iron depleted patients, eight from each group, subsequent treatment with alpha-interferon produced a response in only one patient. These results suggest that increased liver iron is a negative prognostic factor for alpha-interferon response in chronic hepatitis C. Iron depletion had a beneficial effect on serum alanine aminotransferase in all the patients treated, but did not improve the response to alpha-interferon.

Hepatitis C virus genotypes and reinfection of the graft during long-term follow-up in 35 liver transplant recipients

To understand the clinical outcome of hepatitis C virus (HCV) recurrence, data from 35 liver transplant recipients who survived more than 6 months were reviewed. The presence of HCV-RNA was evaluated and genotyping was performed. On the basis of alanine aminotransferase (ALT) levels, patients were sorted into four groups. In 20 patients, a chronic elevation in ALT was found; HCV-RNA detection was positive in 17/17 and the following genotypes were found in 15 of them: 1b in ten patients, 2a in four patients, and 3a in one patient. In 11 patients, ALT levels remained normal throughout follow-up; in nine of them HCV-RNA was positive; HCV genotyping was available in eight patients and identified type 1b in two, type 2a in five, and type 3a in another patient. In two patients, ALT fluctuated above and below the upper limits of normality; type 1b HCV-RNA was found in one of them. In two patients, after an initial period of normality, ALT levels showed an abrupt rise; HCV-RNA was positive and type 1b was identified in both patients. Eight patients developed HCV-related deep jaundice and three of them spontaneously recovered. Progressive hepatic injury occurred in eight patients, six with chronic ALT elevation and two showing a late ALT elevation; genotype 1b was present in seven patients while in one, genotype 3a was found; sub-acute graft failure developed in five of them, leading to death in two and retransplantation in the others; the other three patients are alive with recurrent overt cirrhosis. The 1, 3, and 5 year actuarial survivals were 89%, 79%, and 63% respectively. The 1, 3, and 5 year actuarial risks of progressive graft damage were 6%, 7%, and 15%, respectively. In conclusion, HCV reinfection causes a slow decrease in the long-term patients' survival. Persistent elevation of ALT is more frequently observed in patients with genotype 1b infection.