W. Schaasberg

Confirmation of hepatitis C virus infection by new four-antigen recombinant immunoblot assay

A new four-antigen recombinant immunoblot assay (4-RIBA) for confirmation of hepatitis C virus (HCV) C-100 enzyme-linked immunosorbent assay (ELISA) reactivity was tested in stored serum samples (1984-86) of blood donors and recipients and compared with results from polymerase chain reaction (PCR) analysis of fresh (1990) plasma samples in donors and recipients from the original study. Of 37 HCV C-100 ELISA-positive blood products, 8 were 4-RIBA positive, of which 7 were implicated in post-transfusion non-A, non-B hepatitis (PT-NANBH) and/or PCR confirmed recipient HCV infection. Of 9 recipients with PT-NANBH, 8 were reactive in 4-RIBA (6 positive and 2 indeterminate). With fresh plasma samples, 3 donors and 6 recipients who were 4-RIBA positive were also PCR positive. 4 4-RIBA indeterminate and 78 4-RIBA negative samples of donors and recipients were PCR negative. Of 6 4-RIBA positive recipients, 5 were PCR positive four to six years later. 1.6% of the 383 recipients became chronically infected with HCV. The new 4-RIBA represents a candidate confirmation test to discriminate between infective and non-infective HCV C-100 ELISA-positive blood donors.

Infectivity of blood seropositive for hepatitis C virus antibodies

Stored serum samples from 5150 blood product transfusions and 383 recipients were tested for antibodies to hepatitis C virus (anti-HCV) by a recombinant enzyme-linked immunosorbent assay (ELISA) as part of a prospective study on post-transfusion non-A, non-B hepatitis (NANBH). Donor cofactors associated with HCV infectivity of anti-HCV-positive blood products were raised alanine aminotransferase concentrations (6 of 9 infective vs 1 of 26 not infective); a mean ELISA optical density/cut-off ratio greater than or equal to 2 (7 of 9 vs 9 of 26); both preceding factors (together in 6 blood products, all of which transmitted infection); and persistent donor anti-HCV seropositivity. Use of anti-HCV screening to prevent post-transfusion NANBH was compared with measurement of alanine aminotransferase concentrations: a corrected efficacy of 63% and 65%, a specificity of 93% and 64%, and a positive predictive value of 16.2% and 3.6% were found, respectively; 0.7% or 3.8% of blood donations, respectively, would be discarded. Blood donor screening for anti-HCV is recommended to reduce the incidence of post-transfusion NANBH.

The PROTON study: profiles of blood product transfusion recipients in the Netherlands

Background  Transfusion recipient data are needed for correct estimation of cost‐effectiveness in terms of recipient outcomes after transfusion. Also, such data are essential for monitoring blood use, estimation of future blood use and benchmarking.

Early Antihepatitis C Virus Response with Second—Generation C200/C22 ELISA

Detection of early antibody to hepatitis C virus (HCV) by a new second‐generation C200/C22 anti‐HCV enzyme‐linked immunosorbent assay (ELISA) and a four‐antigen recombinant immunoblot assay (4‐RIBA) was compared with the first‐generation anti‐HCV C100 ELISA using sequential serum samples of 9 recipients who were infected with HCV, as detected by polymerase chain reaction after transfusion of blood products. Within 26 weeks after transfusion, 9/9 (100%) recipients seroconverted with C200/22 ELISA, and 6/9 (67%) seroconverted with C100 ELISA. Compared with C100 ELISA, C200/C22 ELISA seroconversion occurred simultaneously in 3 cases, 5–6 weeks earlier in 3 other cases, and 20 weeks earlier in 1 case. Seven of 9 (78%) recipients became positive, and 2/9 (22%) became indeterminate with 4‐RIBA. In 8 cases with clinical posttransfusion hepatitis non‐A, non‐B (PTH‐NANB), anti‐HCV C200/C22 ELISA seroconversion occurred 2–17 (mean 6) weeks after the onset of hepatitis. In 6 cases of PTH‐NANB, anti‐HCV C100 ELISA seroconversion occurred 2–26 (mean 9) weeks after the onset of hepatitis. It is concluded that the second‐generation C200/C22 ELISA is more sensitive than the C100 ELISA for the detection of antibody during early HCV infection. Indeterminate 4‐RIBA results are found in the early phase of HCV infection.

Enhanced Sensitivity of a Second Generation ELISA for Antibody to Hepatitis C Virus

A second generation ELISA for combined detection of antibodies to three hepatitis C virus (HCV) recombinant proteins, i.e. C100, C33c and core, was compared with a first generation anti‐HCV ELISA in which only antibodies to C100 are detected. The results of the ELISAs were evaluated in 225 haemophilia patients (panel A) and 44 patients with non‐A, non‐B (NANB) hepatitis (panel B). HCV infection was established by cDNA‐polymerase chain reaction (PCR) (in panel B only) and by studying the anti‐HCV reaction patterns in 4 separate ELISAs for detection of antibodies to the recombinant proteins C100, C33c, core and a combination of two synthetic peptides sp67/65 derived from the C100 region. The sensitivity for the detection of HCV infection had increased from 0.92 [95% confidence interval (CI): 0.87–0.95] to 1.00 (95% CI: 0.98–1.00) in haemophiliacs and from 0.84 (95% CI: 0.66–0.95) to 1.00 (95% CI: 0.89–1.00) in NANB hepatitis patients when the second generation ELISA was used instead of the first generation ELISA. Concurrently the chance of a false negative result was reduced in panel A and B from 0.37 to 0 and from 0.28 to 0, respectively. Analysis of anti‐HCV reaction patterns revealed that 172 of 206 (83.5%) anti‐HCV ELISA‐reactive haemophilia patients had antibodies to all 4 antigens tested. In the NANB hepatitis patients 18 of 31 (58.1%) anti‐HCV ELISA‐reactive subjects reacted with 4 antigens. In the PCR tested panel of NANB hepatitis patients 2 subjects who showed antibody reactivity to only one antigen and 5 patients with reactivity to 2 antigens were PCR‐positive. On the other hand, 1 NANB hepatitis patient showed antibody reactivities to all 4 antigens tested, but was PCR‐negative. Antibodies to core were the most prevalent in the two populations studied. We conclude that the introduction of the second generation anti‐HCV ELISA will significantly reduce the likelihood of unrecognized HCV infection.

Survival after transfusion in the Netherlands

Background  Cost‐effectiveness analyses of blood safety interventions require estimates of the life expectancy after blood product transfusion. These are best derived from survival after blood transfusion, per age group and blood component type.

Monitoring viral incidence rates: tools for the implementation of European Union regulations

Background and Objectives  European legislation requires manufacturers of plasma products to report epidemiological data on human immunodeficiency virus, hepatitis B virus and hepatitis C virus in donor populations. The incidence rates of such infections are directly related to the risk of infection transmission. We propose two statistical tests to evaluate these incidence rates.