H. Vrielink

Reliability of the third-generation recombinant immunoblot assay for hepatitis C virus

BACKGROUND: In a confirmatory laboratory, the second‐generation recombinant immunoblot assay (RIBA‐2) was replaced by the third‐ generation RIBA (RIBA‐3) in March 1993. The aim of this validation study was to compare the sensitivity and specificity of RIBA‐2 and RIBA‐ 3 in a routine setting, by using a validated hepatitis C virus (HCV) RNA polymerase chain reaction to establish plasma viremia.

Performance of three generations of anti-hepatitis C virus enzyme- linked immunosorbent assays in donors and patients

BACKGROUND: Prevention of posttransfusion non‐A,non‐B hepatitis in recipients of blood components improved considerably with the introduction of the second‐generation of hepatitis C virus (HCV) antibody tests. In 1993, third‐generation HCV antibody assays were introduced in Europe. STUDY DESIGN AND METHODS: The performance of three generations of anti‐HCV enzyme‐linked immunosorbent assay (ELISA) (ELISA‐1, −2, −3) was compared in routine blood donor screening (99,394 donations were tested with ELISA‐1, 167,999 donations with ELISA‐2, and 262,090 donations with ELISA‐3) and in serial samples from nine patients with documented acute posttransfusion HCV infection. RESULTS: Eight (0.01%) repeat donors, previously negative in ELISA‐1, were found positive in ELISA‐2 and were confirmed as positive in second‐generation recombinant immunoblot assay and/or cDNA polymerase chain reaction. In the donor population, no difference in the sensitivity of ELISA‐2 and ‐ 3 was observed. The specificity of the three generations of ELISAs was comparable (99.8, 99.7, and 99.7%). In seroconversion samples, ELISA‐2 and −3 detected HCV antibodies at the same time in seven patients, but in two patients, ELISA‐3 found HCV antibodies, respectively, 63 and 77 days earlier than ELISA‐2 did. In the seroconversion samples, ELISA‐2 and −3 were significantly more sensitive than second‐ and third‐ generation recombinant immunoblot assays. CONCLUSION: ELISA‐3 did not detect more HCV‐infected individuals in a donor population that previously tested negative in ELISA‐2, but it did detect HCV antibodies earlier in some patients with acute HCV infection. ELISA‐2 and −3 were significantly more sensitive than second‐ and third‐generation recombinant immunoblot assays.

Look-back study of infectivity of anti-HCV ELISA-positive blood components

The infectivity of blood components from donors who were later found to be anti-HCV ELISA-positive was investigated in recipients who were enrolled in a look-back programme. Recipients received ELISA-positive blood components from donors who were PCR-positive and/or RIBA-2-positive (n = 22, group A) or PCR-negative and indeterminate or negative on RIBA-2 (n = 105, group B). 26 of 32 (81%) recipients of group A donors and none of 140 of group B were HCV-infected. All stored serum samples of previous donations (n = 172) of group A donors were anti-HCV-positive in RIBA-3, indicating a chronic carrier state of HCV in these donors.

Prevalence of leucocyte antibodies in the Dutch donor population

Introduction  Donor leucocyte antibodies have been associated with transfusion‐related acute lung injury (TRALI) and can be present in allo‐exposed donors. Donor deferral policies aiming at excluding allo‐exposed donors are increasingly implemented worldwide. We aimed at assessing the prevalence of leucocyte antibodies in different subgroups of allo‐exposed donors in the Dutch donor population.

Sensitivity and Specificity of Three Third‐Generation Anti‐Hepatitis C Virus ELISAs

Three commercially available 3rd‐generation anti‐HCV ELISAs (Abbott, Murex and Ortho) were evaluated in various serum panels: (A) blood donor samples (n = 403) with 1st‐ or 2nd‐generation anti‐HCV ELISA (various manufacturers) positive test results; (B) non‐A, non‐B hepatitis patients (n = 212); (C) multitransfused patients (n = 253); (D) serial dilutions of HCV confirmed (RIBA and PCR) positive blood donors (n = 24), and (E) first‐time blood donors (n = 1,055). All samples of panels A, B and C were tested in PCR and RIBA‐2. In panels A, B and C, 398 samples were HCV PCR positive: all were detected by Abbott and Ortho, and 397 (99.7%) by Murex. The sample missed by the Murex ELISA showed an isolated anti‐C33c reactivity in RIBA‐2. In panels A–C, 442 samples were RIBA‐2 positive and all were detected by the 3 tests. With Probit analysis on results of panel D, no significant difference in sensitivity was observed between the 3 evaluated ELISAs. Specificities of Abbott, Murex and Ortho in 1,055 blood donors were 99.7, 99.3 and 99.9%, respectively (NS, χ2). We conclude that the sensitivity and specificity of the 3 ELISAs are comparable although the C33c antigen in the Murex VK47 test should be improved.

Transfusion-transmissible infections

Infectious agents, including viruses, bacteria, and parasites, can be transmitted by human blood products. Of major importance are viruses such as human immunodeficiency virus types 1 and 2 (HIV-1/2), hepatitis B virus (HBV), hepatitis C virus (HCV), and human T-cell lymphotropic virus types I and II (HTLV-I/II). Also, other viruses such as cytomegalovirus, Epstein-Barr virus, human parvovirus B19, and hepatitis A and G viruses can be transmitted by blood products. Various methods are used to prevent transmission of blood-borne agents to recipients, such as donor selection, testing donated blood for various infectious agents, and viral inactivation of plasma derivatives. With all these precautionary measures, the estimated risk for infection by screened blood components in Europe and the United States is approximately 1 in 50,000 to 1.6 million (for HBV, HCV, and HIV-1/2) transfused blood components. In the future, the safety of blood components may be increased by testing donated blood by nucleic acid amplification techniques and by photochemical decontamination of cellular blood components.

Confirmation of hepatitis C infection : a comparison of five immunoblot assays

BACKGROUND: Recently, new immunoblot assays for the detection of antibodies to hepatitis C virus (HCV) became available.

Donor Selection: The Exclusion of High Risk Donors?

Selection of donors is an important means to improve the overall safety of the blood supply. Since the AIDS epidemic emerged and after the introduction of sensitive screening tests for HIV, it became clear that blood donations given in the infectious ‘window’ period, formed the most important risk for recipients of blood products. Therefore, selection criteria became more and more stringent to exclude these high risk donors. Means to exclude high risk donors are non‐ remuneration, including a clear policy to provide no incentives which can be readily converted to cash, the avoidance of replacement donations, the discouragement of ‘HIV test seeking’ donors, education and information of donors about HIV and other blood‐borne infectious diseases and the in depth questioning about risk behaviour, orally as well as by questionnaires. Although this policy of donor selection is recognized by most blood centers in the world, the efficacy of this selection has not been well documented. Therefore in future, studies should be performed to base these selection criteria on evidence.

Evaluation of a New HTLV-I/II Polymerase Chain Reaction

Aim: Evaluation of a qualitative HTLV‐I/II DNA polymerase chain reaction (PCR) test for the detection of HTLV‐I/II DNA (Roche Diagnostic Systems, Branchburg, N.J., USA) in various panels. Methods: The panels consisted of fresh EDTA blood samples from blood donors who were anti‐HTLV‐I/II ELISA repeatably reactive: 53 were Western blot (WB) positive, 228 were WB indeterminate and 15 were WB negative. Elevent ELISA‐negative blood donors were used as negative controls. Furthermore, specimens from 1 HTLV‐II‐infected intravenous drug user and from 1 HTLV‐II‐infected blood donor were included in the panel. Peripheral blood lymphocytes were prepared by red blood cell lysis with the Roche washing solution and stored at < –23 °C until processing. Amplification products were analyzed with the HTLV‐I/II detection kit. Results: All 53 anti‐HTLV‐I/II ELISA‐ and WB‐positive samples and both HTLV‐II‐positive samples tested positively by PCR. All 228 anti‐HTLV‐I/II ELISA‐positive and WB‐indeterminate, all 15 ELISA‐positive and WB‐negative and all 11 ELISA‐negative control samples tested negative by PCR. Conclusion: The Roche Amplicor HTLV‐I/II test is a simple test, suitable for the confirmation of HTLV‐I and ‐II infection in individuals with indeterminate or positive WB patterns.

Efficacy of Selected versus Random Blood Donor Screening for Anti‐HTLV‐I Antibodies

Transmission of human T-cell lymphotropic virus (HTLV-I) infection may occur by transfusion of cellular blood products from anti-HTLV-I positive donors with a 20-63Y0 efficiency [I, 21. Transfusion of HTLV-I-infected blood products may be associated with accelerated development of HTLV-I-associated myelopathy (HAM) within I month to 4 years after transfusion [3-51. Screening of donor blood for anti-HTLV-1 antibodies and subsequent exclusion of HTLV-I seropositive blood donors is not only effective in preventing transfusion-transmitted HTLV-I infection, but also in preventing transfusion-associated myelopathy [3,4]. The aim of our study was to establish the efficacy of anti-HTLV-I screening of blood donors born in known HTLV-I endemic areas, as compared to routine screening of all blood donations. From December 1991 to January 1993 (period A), all blood donors of the Red Cross Blood Bank Amsterdam were questioned whether they were born in areas endemic for HTLV-I, which at the time were defined as: Japan, Caribbean Islands, Western and Central Africa and South America [6]. If donors w r e born in these areas, they were tested once, after obtaining informed consent, for anti-HTLV-l antibodies with an anti-HTLV-Ienzyme-linked immunosorbent assay (ELISA, Vironostika HTLV-I MicroELISA System, Organon Teknika Corporation, Durham, USA). ELISA-positive (= repeatedly reactive) samples were tested in an HTLV-1/11 Western blot (WB, DBL HTLV Blot 2.3, Diagnostic Biotechnology, Singapore) [7]. ELISA positive and WB positive or indetermiEfficacy of Selected versus Random Blood Donor Screening for Anti-HTLV-l Antibodies