Use of third-generation hepatitis C virus (HCV) enzyme immunoassay (EIA) to resolve second-generation HCV EIA-reactive and second-generation recombinant immunoblot assay-indeterminate blood samples: data to support current Food and Drug Administration guidance on HCV lookback

Hepatitis C transmission from seropositive, nonviremic donors to non-hepatitis C liver transplant recipients

Breakthroughs in hepatitis C virus (HCV) treatment and rising rates of intravenous drug use have led to an increase in the number of organ donors who are HCV antibody-positive but serum nucleic acid test (NAT)-negative. The risk of HCV transmission from the liver grafts of these donors to recipients is unknown. To estimate the incidence of HCV transmission, we prospectively followed 26 consecutive HCV antibody-negative (n = 25) or NAT-negative (n = 1) transplant recipients who received a liver graft from donors who were HCV antibody-positive but serum NAT-negative between March 2016 and March 2017. HCV transmission was considered to have occurred if recipients exhibited a positive HCV PCR test by 3 months following transplantation. Drug overdose was listed as the cause of death in 15 (60%) of the donors. One recipient died 18 days after transplantation from primary graft nonfunction and was excluded. Of the remaining 25 recipients, HCV transmission occurred in 4 (16%), at a median follow-up of 11 months, all from donors who died of drug overdose. Three of these patients were treated with direct-acting antiviral therapy, with two achieving a sustained virologic response and one an end-of-treatment response. One patient with HCV transmission died after a complicated postoperative course and did not receive antiviral therapy.

CONCLUSION

In this prospective cohort of non-HCV liver recipients receiving grafts from HCV antibody-positive/NAT-negative donors, the incidence of HCV transmission was 16%, with the highest risk conferred by donors who died of drug overdose; given the availability of safe and highly effective antiviral therapies, use of such organs could be considered to expand the donor pool. (Hepatology 2018;67:1673-1682).

The clinical relevance of persistent recombinant immunoblot assay-indeterminate reactions: insights into the natural history of hepatitis C virus infection and implications for donor counseling

BACKGROUND

Recombinant immunoblot assay (RIBA) is used to determine the specificity of antibody to hepatitis C virus (anti-HCV). The RIBA result is recorded as positive, negative, or indeterminate. The interpretation and significance of RIBA-indeterminate reactions are unclear. We addressed the clinical relevance of these reactions in the context of the natural history of HCV infection in a prospectively followed cohort of anti-HCV-positive blood donors.

STUDY DESIGN AND METHODS

Donor demographics, exposure history, and humoral and cell-mediated immunity (CMI) were compared in 15 RIBA-indeterminate subjects, nine chronic HCV carriers, and eight spontaneously recovered subjects. Serum samples were tested for anti-HCV by a quantitative, liquid luciferase immunoprecipitation system (LIPS). CMI was assessed by interferon-γ enzyme-linked immunosorbent spot assay.

RESULTS

In the LIPS assay, the sum of antibody responses to six HCV antigens showed significant (p < 0.001) stepwise diminution progressing from chronic carriers to spontaneously recovered to RIBA-indeterminate subjects. CMI responses in RIBA-indeterminate subjects were similar to spontaneously recovered subjects and greater than chronic carriers and controls (p < 0.008). A parenteral risk factor was identified in only 13% of RIBA-indeterminate subjects compared to 89% of chronic carriers and 87% of spontaneously recovered subjects. RIBA-indeterminate donors were older than the other groups.

CONCLUSION

The CMI and LIPS results suggest that persistent RIBA-indeterminate reactions represent waning anti-HCV responses in persons who have recovered from a remote HCV infection. In such cases, detectable antibody may ultimately disappear leaving no residual serologic evidence of prior HCV infection, as reported in a minority of long-term HCV-recovered subjects.

High antibody level: an accurate serologic marker of viremia in asymptomatic people with hepatitis C infection

BACKGROUND

The screening and diagnosis of hepatitis C virus (HCV) infection is initiated by testing for antibody to HCV (anti-HCV). A positive anti-HCV test in blood donors represents ongoing infection in only a variable proportion of individuals. Because a high anti-HCV level has been associated with viremia, a study was conducted to determine whether a high antibody level is an accurate serologic marker for viremia in asymptomatic anti-HCV-positive persons.

STUDY DESIGN AND METHODS

In a diagnostic test study, we included 856 anti-HCV-positive blood donors in a blood bank at Guadalajara, Jalisco, Mexico, between 2002 and 2007. A third-generation amplified chemiluminescence assay (ChLIA HCV) was used to detect anti-HCV. A positive result of the qualitative nucleic acid test (HCV RNA) was considered the gold standard for viremia.

RESULTS

By receiver operating characteristic analysis, the signal-to-cutoff (S/CO) ratio of 20 or more was chosen as optimal to identify viremia and so was defined as high anti-HCV level. There was a significant difference in the proportion of viremia between subjects with high antibody level and those with lower levels (93.7% vs. 1.8%, respectively; p < 0.001). A high antibody level showed a sensitivity for viremia of 96.6% (95% confidence interval [CI], 93.8%-98.1%), a specificity of 96.6% (95% CI, 94.8%-97.8%), and a likelihood ratio of 28.6 (95% CI, 18.4%-44.6%).

CONCLUSION

A high antibody level (S/CO ratio >/=20 by ChLIA HCV) clearly divides the viremic from the nonviremic blood donors and functions as an accurate serologic marker to guide the use of routine HCV RNA testing to confirm hepatitis C infection.

Molecular and contextual markers of hepatitis C virus and drug abuse

The spread of hepatitis C virus (HCV) infection involves a complex interplay of social risks, and molecular factors of both virus and host. Injection drug abuse is the most powerful risk factor for HCV infection, followed by sexual transmission and additional non-injection drug abuse factors such as co-infection with other viruses and barriers to treatment. It is clearly important to understand the wider context in which the factors related to HCV infection occur. This understanding is required for a comprehensive approach leading to the successful prevention, diagnosis, and treatment of HCV. An additional consideration is that current treatments and advanced molecular methods are generally unavailable to socially disadvantaged patients. Thus, the recognition of behavioral/social, viral, and host factors as components of an integrated approach to HCV is important to help this vulnerable group. Equally important, this approach is key to the development of personalized patient treatment - a significant goal in global healthcare. In this review, we discuss recent findings concerning the impact of drug abuse, epidemiology, social behavior, virology, immunopathology, and genetics on HCV infection and the course of disease.

Clinical and laboratory characteristics of acute hepatitis C in patients with end-stage renal disease on hemodialysis

BACKGROUND

Patients with end-stage renal disease (ESRD) undergoing hemodialysis are a risk group for hepatitis C virus (HCV) infection. The characteristics of acute hepatitis C infection in this population are not well known.

GOALS

To evaluate the clinical and laboratory characteristics of acute hepatitis C in ESRD patients treated with hemodialysis.

STUDY

ESRD patients on hemodialysis with acute hepatitis C, characterized by elevated alanine aminotransferase (ALT) followed by anti-HCV seroconversion were studied.

RESULTS

Thirty-six patients (58% females, 44+/-12 y), with a mean time on hemodialysis of 2 years, were included. Only 2 (6%) patients had jaundice. ALT elevation was observed in all patients. Median peak ALT was 4.7 x upper limit of normal. The median interval between ALT elevation and anti-HCV seroconversion was 1 month (0 to 8). None of the patients with detectable HCV-RNA showed spontaneous clearance of viremia within 12 weeks of follow-up. Three (8%) patients presented ALT elevation followed by anti-HCV seroconversion with undetectable HCV-RNA.

CONCLUSIONS

Acute hepatitis C is frequently asymptomatic in ESRD patients on hemodialysis and should be suspected in all patients presenting elevated ALT. Determination of HCV-RNA is important for the confirmation of infection. Anti-HCV seroconversion seems to occur early and spontaneous clearance of HCV-RNA is uncommon.

Can we improve the management of blood donors with nonspecific reactivity in viral screening and confirmatory assays?

Donors with nonspecific reactivity in viral screening or confirmatory assays are problematic for blood services because of donor management issues and product loss. Considerable experience has now accumulated in the use of screening and confirmatory assays; therefore, it is timely to examine the ways in which donors with nonspecific reactivity are managed. In this review, we summarize the causes and characteristics of nonspecific reactivity in blood donors and approaches for reducing the number of nonspecific reactive results and we offer some suggestions for improving the management of these donors.

Comparison of conventional tube test technique and gel microcolumn assay for direct antiglobulin test: a large study

Gel microcolumn assay (GMA) is a modified serological technique that has been used for ABO and Rh typing, direct antiglobulin test (DAT), detecting alloantibodies, red cell phenotyping, and other applications. However, for DAT, the role of GMA is controversial. The purpose of this large study was to compare the performance of the conventional tube test (CTT) to GMA for detecting potentially significant antibodies coating red blood cells in vivo. From January 1996 to May 2002, we performed DATs by GMA and CTT on 9,862 blood samples submitted to our reference laboratory, using LISS/Coombs cards (DiaMed-Latino America, Lagoa Santa-MG, Brazil) for GMA and polyspecific and monospecific anti-IgG reagents for CTT. Acid eluates were prepared from all positive DAT samples. The specificity of eluates was determined by GMA. We detected nonconcordant results in 2,079 out of 3,163 positive DATs (65.7%). All of these tests were only positive in GMA. Sensitivity and specificity for DATs was 100% and 83.0% for gel, and 50.7% and 97.8% for tube, respectively. Based on this study GMA showed to be more sensitive than CTT for detecting potentially significant antibodies coating red blood cells in vivo.

The significance of third-generation HCV RIBA-indeterminate, RNA-negative results in voluntary blood donors screened with sequential third-generation immunoassays

BACKGROUND

One of the problems associated with the use of anti-HCV immunoblot assays is the interpretation of indeterminate results without detectable HCV RNA. The purpose of this study was to examine the significance of third-generation RIBA (RIBA-3)-indeterminate, RNA-negative results in voluntary blood donors.

STUDY DESIGN AND METHODS

Since June 2000 all Australian Red Cross Blood Service testing sites have used an anti-HCV sequential immunoassay testing strategy whereby donors who are reactive on the primary screening immunoassay are tested on a secondary immunoassay and if reactive on both assays, further tested by immunoblot. From the four testing sites that use RIBA-3, the result profiles of donors who were RIBA-3-indeterminate, HCV RNA-negative were analyzed.

RESULTS

From 2,661,786 donations screened for anti-HCV during the study period, 102 RIBA-3-indeterminate, RNA-negative donors were identified, most of whom were reactive to either c33p (69.6%) or c22p (27.5%). The RIBA-3-indeterminate, RNA-negative donors showed a significantly higher screening immunoassay signal strength to assay cutoff (S/CO) distribution than those with biologic false-reactive (BFR) results (1.853 vs. 1.524, p < 0.05) but a significantly lower distribution than RIBA-3-positive, RNA-negative (1.853 vs. 4.546, p < 0.05) or RNA-positive (1.853 vs. 6.467, p < 0.05) donors. The RIBA-3-indeterminate, RNA-negative donors showed a similar distribution of c33c and c22p band intensities compared with RIBA-3-positive, RNA-negative donors but significantly lower distribution of band strengths compared to the RIBA-3-positive, RNA-positive group. Compared to the indeterminate donors with previous anti-HCV-negative or BFR results, the indeterminate donors not previously screened for anti-HCV showed higher immunoassay S/CO ratio distributions, a higher proportion with c22p reactivity (16.2% vs. 36.7%), and higher frequency of risk factors (46.4% vs. 75.0%).

CONCLUSIONS

Our analysis suggests that a combination of indicators can be used to help clarify RIBA-3-indeterminate, RNA-negative results. Specifically, donors with high S/CO ratios on a screening immunoassay, RIBA-3 reactivity to c22p or c33c with band intensity of 2+ or greater, without a previous history of negative or BFR donations and with an identifiable risk factor, have a high probability of representing true anti-HCV rather than nonspecific reactivity.

Retrospective targeted HCV lookback using centralized contracted notification service

BACKGROUND

Mandated HCV 2.0 lookback significantly challenged the human and financial resources available to the six Los Angeles County Department of Health Services (DHS) hospital blood banks. To comply with FDA requirements, DHS developed a centralized process that utilized the services of a contract vendor for performing HCV lookback.

STUDY DESIGN AND METHOD

A DHS public health nurse acted as HCV lookback coordinator and as liaison with the vendor. Cases were electronically forwarded to the vendor, who then reviewed the patient's chart to obtain information necessary for tracking the patient through commercial databases. The vendor was responsible for notifying the recipient for pretest counseling and for providing documentation of all efforts.

RESULTS

In total, 411 recipients were identified, of which, 168 cases were completed by the hospitals, 243 were forwarded to the vendor, 50 percent were deceased, 21 percent were contacted, and 28 percent could not be contacted, and 1 percent could not be located on any databases. The vendor contacted 35 of 66 cases that the hospitals had unsuccessfully attempted to contact. Of the cases forwarded to the vendor, 82 percent were completed on time. Delays were attributable to the vendor in less than 2 percent of cases. The cost per case forwarded to the vendor was 322 US dollars.

CONCLUSION

Utilizing a professional service to conduct HCV recipient notifications is an effective strategy for meeting FDA deadlines and for freeing transfusion service staff to perform critical functions. It remains to be seen whether such strategies offer a cost savings.

Impact of changes in viral marker screening assays

BACKGROUND

Monitoring the performance of routinely used infectious disease serologic tests is necessary to evaluate their effectiveness in identifying true-positive units and erroneously disqualifying safe blood donors.

METHODS

With two large screening test data sets collected between 1991 and 1998 and between 1997 and 2000, the impact of changes in screening assays for HIV, HCV, and HBsAg was analyzed with regard to the prevalence of confirmed-positive, indeterminate, and confirmed-negative results and the deferral of donors with an indeterminate or negative results (donor loss).

RESULTS

The prevalence of indeterminate results and donors loss increased significantly in the 6 months after introduction of an HIV-1/2 EIA. A second-generation HCV EIA increased the detection of confirmed-positive donations in repeat donors (p < 0.001) and increased the prevalence of indeterminate donations. Implementation of a third-generation HCV EIA resulted in a significant decrease in indeterminate results in first-time donors. Nonspecific test results increased when HBsAg test kits from a different manufacturer were introduced or different lots of HIV antibody screening test kits from the same manufacturer were used.

CONCLUSION

Introduction of newly licensed versions of assays, switching kit manufacturers, and lot-to-lot variations have an impact on rates of deferrals of safe donors as well as sensitivity of routine screening. Before considering changes in screening tests, blood centers should be aware of, and evaluate, the potential impact on donor loss.

Antiviral treatment responses in patients with chronic hepatitis C virus infection evaluated by a third generation anti-hepatitis C virus assay

Antibodies to hepatitis C virus (HCV) may decrease or disappear after viral clearance in treated or spontaneously resolved infection. We evaluated the usefulness of serial antibody assays in predicting the antiviral treatment responses. One hundred and four chronic hepatitis C patients who received 24 weeks of interferon and ribavirin combination therapy were assayed with a third generation enzyme immunoassay anti-HCV. The mean titre of anti-HCV decreased by more than 50% (from 89.5 +/- 10.8 to 43.6 +/- 17.5) at 48 weeks post-treatment in patients with a sustained virological response, while in nonsustained virological responders and nonresponders, the titres remained over 85% of the pretreatment level at 48 weeks post-treatment. There was a divergence of anti-HCV titres between sustained and nonsustained virological responders during 6-9 months. By using the ratio of 9-month to 6-month titres as an index and receiver operator characteristic curve analysis with the cut-off point set at 90%, we could differentiate sustained virological responders from nonsustained virological responders with a sensitivity and specificity of 91.7% and 90.9%, respectively, 3 months after treatment. The titre of this third generation anti-HCV decreased progressively in sustained virological responders and this assay may be used to monitor and predict antiviral treatment responses.

Hepatitis C lookback

Hepatitis C was responsible for the majority of cases of posttransfusion hepatitis before the introduction of a specific screening test for blood donors. Infected recipients may remain asymptomatic for many years, but cirrhosis and hepatocellular carcinoma may develop decades after infection. Lookback, or the identification of recipients of potentially contaminated blood, is now being conducted in many countries, including Holland, Denmark, the United Kingdom, Canada, New Zealand, and the United States. In targeted lookback, recipients of blood from donors subsequently found to be positive for hepatitis C are notified and advised to undergo testing. In general lookback, all patients who received blood before being tested for hepatitis C are advised to undergo testing. Difficulties with both forms of lookback illustrate the importance of vein-to-vein tracking of blood products, including the potential utility of a centralized registry of blood product recipients.