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H L Zaaijer

Publications and source records attributed to H L Zaaijer.

At least 55 records · Page 3Linked to original sources
PubMed1995

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, chi 2). 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.

Blood Donors↗
PubMed1995

Transmission of hepatitis C virus by anti-HCV-negative blood transfusion. Case report.

Acute posttransfusion hepatitis C was reported in a recipient of 3 units of red cells. The recipient became acutely icteric 6 weeks after transfusion, and HCV infection was diagnosed. Stored serum samples of the 3 implicated donations, which were negative with ELISA-2, were retested by PCR and 3rd-generation antibody tests. One implicated donation was PCR positive, but anti-HCV negative. Both other donations were negative in all tests. The donor was recalled to the Blood Bank 13 weeks after the implicated donation and was found to be ELISA-3 plus RIBA-3 positive. Eight months after the implicated donation, the donor is still PCR and RIBA-3 positive, whereas the recipient became PCR negative but remained anti-HCV RIBA-3 positive. The case shows that blood products from donors collected during the open window period of an HCV infection can transmit HCV to recipients.

DNA-Directed DNA Polymerase↗
PubMed1995

Risk of hepatitis A in Dutch hemophilia patients.

Recently, clotting factor preparations transmitted hepatitis A virus (HAV) to hemophilia patients. To study the risk of HAV infection in Dutch hemophilia patients, serum samples of 341 patients with hemophilia were tested for HAV antibodies (anti-HAV). 197/341 patients (group 1) were treated with clotting factor concentrates produced from large plasma pools, 144/341 patients (group 2) were treated with small pool cryoprecipitate. The test results were compared to those of healthy blood donors (n = 19,746) of the same age. In addition stored serum samples (1983-1994) from hemophilia patients were tested for HAV antibodies. No increased risk of HAV infection was found in Dutch hemophilia patients. The anti-HAV prevalence in group 1 was 20%, in group 2 13% and in blood donors 41%. A significantly (p < 0.002) lower percentage of HAV antibodies was found in hemophilia patients born in the 1950s using cryoprecipitate (11%) as compared to blood donors of the same age (40%), probably caused by passive administration of anti-HAV through clotting product. Passive immunization in the past was significantly (p < 0.02) more often found in group 2 (41.7%) than in group 1 (28%). In the period 1983 till 1988 five seroconversions were seen in group 1 (2%) and one in group 2 (0.7%). Anti-HAV seroconversions were not observed after 1988. In a risk analysis we estimated that 2 plasma pools of 10,000 Dutch blood donors per year may contain HAV. The absence of HAV among Dutch hemophilia patients suggests that this contamination is successfully inactivated.

Blood Coagulation Factors↗
PubMed1994

E2 and NS5: new antigens for detection of hepatitis C virus antibodies.

The value of two new hepatitis C virus (HCV) antigens for detection of HCV antibodies was studied. These two recombinant antigens were derived from the nonstructural-5 (NS5) and envelope-2 (E2) region of the HCV genome. In a panel of 33 HCV-RNA positive samples with indeterminate Riba-2 confirmatory test results, 29 samples (88%) showed additional antibody reactivity against E2 and 12 samples (36%) showed additional reactivity against NS5. Among 39 HCV-RNA negative, Riba-2 indeterminate donor samples, no additional E2 or NS5 reactivity was found in 34 samples (87%); while 5 samples (13%) showed additional reactivity against NS5 and/or E2. E2 reactivity thus resolved the majority of hitherto indeterminate samples. In serial samples from nine posttransfusion hepatitis C patients, NS5 and E2 antibodies did not appear earlier than classical HCV antibodies. However, E2 antibodies eventually appeared in all nine patients. The recombinant E2 might be a candidate antigen for future HCV antibody assays.

Antibody Specificity↗
PubMed1994

Results of 1-year screening of donors in The Netherlands for human T-lymphotropic virus (HTLV) type I: significance of Western blot patterns for confirmation of HTLV infection.

BACKGROUND: Between January 1993 and January 1994, Dutch blood banks screened approximately 674,000 volunteer donors for the presence of antibodies to human T-lymphotropic virus type I (HTLV-I). STUDY DESIGN AND METHODS: Confirmatory testing was performed on samples from 870 different anti-HTLV-I-reactive donors (0.13% of the total tested). RESULTS: According to the authors' Western blot (WB) interpretation criteria, 15 (0.002%) donors tested HTLV-I-positive in the WB; 201 tested negative, and 654 (75% of donors reacting on enzyme-linked immunosorbent assay) tested indeterminate. Fresh samples from 234 of 870 anti-HTLV-reactive donors were tested for HTLV-I and type II (HTLV-II) DNA by polymerase chain reaction: all 15 WB-positive donors tested positive for HTLV-I DNA; 206 WB-indeterminate and 13 WB-negative donors tested negative for HTLV-I and -II DNA. Application of the manufacturer's (World Health Organization-based) guidelines for WB interpretation would have resulted in the misclassification of 48 (23%) of 206 polymerase chain reaction-negative donors as HTLV-I/II-positive. Risk factors were present in 14 of 15 HTLV-I-infected donors: 8 had a partner from an HTLV-I-endemic area, 4 were from HTLV-I-endemic countries, and 2 had received blood transfusions. CONCLUSION: HTLV-I and -II infection is rare among Dutch blood donors. HTLV screening will prevent few cases of HTLV-related disease, but it will prevent a further spread of the virus by transfusion. In a low-risk population, conservative guidelines for WB interpretation unnecessarily generate an excess of false-positive results.

Blood Donors↗
PubMed1994

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. STUDY DESIGN AND METHODS: The performance of five confirmatory anti-HCV immunoblot assays was studied with samples with known HCV antibody and HCV RNA status. The assays were a third-generation strip recombinant immunoblot assay (RIBA-3, Chiron Corp., Emeryville, CA), a second-generation HCV blot (DB-2 blot, Diagnostic Biotechnology, Singapore), the Wellcozyme HCV Western blot (Murex blot, Murex Diagnostics, Dartford, UK), an immunodot HCV assay (Matrix, Abbott Laboratories, Chicago, IL), and the third-generation HCV line immunoassay (Liatek-III, Organon Teknika, Boxtel, The Netherlands). RESULTS: Sensitivity on samples from 48 HCV RNA-positive, second-generation RIBA (RIBA-2)-positive persons and specificity on samples from 31 low-risk donors was 96 percent or better for all assays. The sensitivity on 31 HCV RNA-positive, RIBA-2-indeterminate samples was as follows: Liatek-III, 94 percent; RIBA-3, 90 percent; Murex blot, 61 percent; Matrix, 55 percent; and DB-2 blot, 39 percent. In testing 39 HCV RNA-negative, RIBA-2-indeterminate donor samples, the percentage found to be negative was Liatek-III, 77 percent; RIBA-3, 67 percent; Murex blot, 49 percent; DB-2 blot, 33 percent; and Matrix, 15 percent. The order of sensitivity on four HCV seroconversion series was (from high to low): RIBA-3, Liatek-III, DB-2 blot, Murex blot, and Matrix; the differences were small. CONCLUSION: Detection of HCV antibodies was not refined by the addition of new HCV antigens (NS5, E2/NS1), but by improved classical antigens (core, NS3, NS4). Replacement of the commonly used RIBA-2 will resolve the status of a high proportion of RIBA-2-indeterminate samples.

Blood Donors↗
PubMed1994

Detection of HIV-1 DNA in leukocytes using a commercially available assay.

Recently, an assay for detection of proviral HIV-1 DNA in leukocytes became commercially available. This assay (Amplicor HIV-1 test, Roche Diagnostic Systems) multiplies HIV-1DNA up to a detectable level, using the polymerase chain reaction. We studied performance of this assay on 74 samples from HIV-1-infected patients and on 41 samples from healthy blood donors. Twice a negative control sample appeared to be erroneously reactive. However, sensitivity and specificity on the patient and donor samples both were 100%. To avoid false-positive results, we advise to repeat initially reactive samples if no other data confirm HIV-infection.

Blood Donors↗
PubMed1994

Comparison of methods for detection of hepatitis B virus DNA.

We compared the performance of four assays for detection of hepatitis B virus (HBV) DNA: the PCR; the branched DNA hybridization assay (Chiron); and two hybridization assays that use liquid hybridization (Abbott) or direct membrane hybridization (MH). Testing 109 random hepatitis B surface antigen-positive patient samples, the percentages found to be HBV DNA positive among 30 hepatitis B e antigen (HBeAg)-positive samples and 79 HBeAg-negative samples were as follows: PCR, 100 and 90%; Chiron, 73 and 25%; Abbott, 67 and 13%; and MH, 40 and 8%. In six hepatitis B surface antigen-positive, HBeAg-negative samples, all three hybridization assays detected HBV DNA. Testing dilutions prepared from the Eurohep HBV DNA standards, the detection limits of the assays appeared to be the following: PCR, 2.5 x 10(2) HBV genomes per ml; Chiron, 2.5 x 10(6) genomes per ml; and Abbott and MH, 2.5 x 10(7) genomes per ml. HBV DNA levels in the dilution series, as reported by the Chiron and MH assays, were, on average, 2 times higher than calculated; the Abbott results were, on average, 19 times lower than calculated. We concluded that high levels of HBV DNA and the presence of HBeAg do not necessarily coincide, that the application of hybridization assays is limited to the monitoring of relatively high levels of HBV DNA, and that further standardization of quantitative HBV DNA assays is necessary to facilitate comparison of HBV DNA levels.

Base Sequence↗
PubMed1993

[Prevalence of human T-cell lymphotropic virus type I among Dutch blood donors].

OBJECTIVE. To establish the prevalence of human T-lymphotropic virus (HTLV) type I among Dutch blood donors. DESIGN. Study to confirm screening results. SETTING. Central Laboratory of the Blood Transfusion Service of the Dutch Red Cross, section Virus Diagnostics, Amsterdam. METHOD. The majority (550,000) of the Dutch blood donors were tested in the course of 1993 for presence of HTLV antibodies. For serological confirmation using the Western Blot test, 20 of the 22 Dutch blood banks sent in blood samples of 714 donors found positive at HTLV screening. Material of 36 of these donors was suitable for testing using the polymerase chain reaction (PCR) for DNA of HTLV types I and II. RESULTS. The Western Blot confirmation test confirmed HTLV infection of 10 of the 714 blood donors; eight of these samples, examined with the PCR test, proved to be positive for DNA of HTLV I. In 537 of the 714 ELISA-reactive donors, the Western Blot test gave doubtful results. The PCR test for HTLV I/II DNA was negative in 26 of these samples, but the possibility could not be excluded that there were HTLV carriers among the other donors with a doubtful Western blot test result. With inclusion of the four donors infected with HTLV I that had been detected earlier, the prevalence of HTLV I among Dutch blood donors is found to be 1:39,000.

Blood Donors↗
PubMed1993

Reliability of polymerase chain reaction for detection of hepatitis C virus.

The polymerase chain reaction (PCR) is used to detect hepatitis C virus (HCV) RNA, and the results of this assay may have a bearing on management of patients. We tested 31 laboratories for performance of HCV PCR with a coded panel that comprised 4 HCV-positive plasma samples, 6 HCV-negative samples, and two dilution series of HCV-positive plasma. 15 (48%) laboratories had faultless results with both dilution series, and 16 (52%) laboratories reported erroneous results with one or both series. 10 (32%) laboratories had faultless results when testing undiluted plasma samples, 11 (35%) produced a false-negative result with a weak-positive sample, and 10 (32%) produced false negative and/or false positive results. Only 5 (16%) laboratories performed faultlessly with the entire panel of samples. Reports of presence of HCV should be interpreted with care until reliable HCV-RNA detection becomes widely available.

Clinical Laboratory Techniques↗
PubMed1993

Hepatitis A antibody titres after infection and immunization: implications for passive and active immunization.

Titres of antibodies against hepatitis A virus (HAV) were determined in patients, in donors, and in volunteers after active, passive, and combined immunization. Highest titres were found in recently infected persons: in 109 IgM anti-HAV positive persons, the geometric mean titre (GMT) was 15,400 mIU/ml. The GMT in 265 anti-HAV positive blood donors was 10,700 mIU/ml. The anti-HAV seroprevalence in 19,746 donors increases with age: at the age of 40 years, 50% have antibodies. Titres after active, passive, and combined immunization were studied in three groups: 51 persons received inactivated HAV vaccine at months 0, 1, and 6. The GMT after the booster was 3,400 mIU/ml at month 7. All persons produced more than 100 mIU/ml anti-HAV. Forty-nine persons received both 5 ml immunoglobulin and three vaccinations, yielding a GMT of 1,300 mIU/ml at month 7. One person in this group produced less than 100 mIU/ml anti-HAV. Forty-nine persons received 5 ml immunoglobulin intramuscularly. At day 5 the GMT was 96 mIU/ml. The estimated minimum protective level (10 mIU/ml) was reached in 3 months. Hepatitis A vaccination may supersede the use of immunoglobulin as prophylaxis for travellers to endemic areas. Passive immunization remains necessary for protection during outbreaks. The dosage regimen for passive immunization is based on old studies using preparations with unknown anti-HAV content. Concern regarding the antibody levels in immunoglobulin preparations is justified; the prevalence of HAV antibodies in developed countries continues to fall. Our results indicate that dosage regimens should be reconsidered. Dosage should be deduced logically from the anti-HAV antibody content of the immunoglobulin preparation.

Adolescent↗