23 research outputs found

    A comparison between one first generation and three second generation anti-HCV ELISAs: an investigation in high- and low-risk subjects in correlation with recombinant immunoblot assay and polymerase chain reaction

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    One first generation assay (manufactured by Ortho, test I) and 3 second generation anti-HCV ELISAs (manufactured by Ortho, Abbott, and UBI, tests II-IV) were compared. Sera from 4 different sources were used: (1) intravenous drug-users (IVDUs, n = 50), (2) blood donors (n = 1055), (3) all clinical samples from one day of routine anti-HCV testing (n = 89), (4) hemodialysis patients previously found negative by test I but clinically suspected to have a HCV infection (n = 11). Confirmatory anti-HCV tests were carried out with a second generation recombinant immunoblot assay (RIBA II). In sera positive exclusively by test IV, one antibody consumption test (UBI HCV Neutralization EIA) and one further immunoblot assay (INNO-LIA HCV Ab) were used. PCR for HCV RNA was carried out on all hemodialysis patient sera and in the RIBA II positive blood donor sera. The second generation ELISAs discriminated 11 more positive samples than the first generation test (2 IVDUs, 5 blood donors, 4 clinical samples). The 9 sera from blood donors and clinical samples were all RIBA II positive or indeterminate. The second generation tests thus showed increased sensitivity. The second generation tests also showed increased specificity in that 4 samples that were positive by test I but negative by the second generation tests, were also negative by RIBA II. With few exceptions, all RIBA II-positive and most of the indeterminate samples were positive by the second generation ELISAs. With few exceptions, all the RIBA II-negative samples were negative by the second generation ELISAs. Eleven blood donor sera were positive by test IV exclusively where RIBA II and other supplementary assays were negative. The recently introduced second generation anti-HCV ELISAs were found to have a higher sensitivity than the first generation test. The tests also showed a good concordance with the exception of test IV in the group of blood donor sera

    Low frequency of hepatitis C antibodies among children from foreign countries adopted in Swedish families

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    89 children from 20 countries adopted to Swedish parents between 1984 and 1988 were tested for the presence of hepatitis C antibodies (anti-HCV). Sera taken soon after their arrival to Sweden were retrospectively analyzed. Two children, an 18-month-old boy from Poland and an 8-month-old girl from India, were anti-HCV positive. The girl from India had lost the anti-HCV antibodies in sera taken at the age of 13 and 14 months. These antibodies were probably passively derived from the mother. The Polish boy had a strong positive reactivity and is likely to have had an HCV infection early in life. Thus, there is a low prevalence of anti-HCV positivity among children from foreign countries adopted in Swedish families

    A microcarrier cell culture system for large scale production of hepatitis A virus

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    Hepatitis A virus (HAV) was isolated from human faeces using a fetal rhesus monkey kidney cell line (Frhk-4). Infectious medium from passage 12 was used to inoculate a large (5000 cm2) microcarrier cell culture maintained in suspension. The microcarriers used were swollen, collagen-coated dextran beads on which it was easy to propagate Frhk-4 cells. Intra- and extra-cellular virus levels were assayed and compared with conventional cultures in 25 cm2 plastic flasks. The results show that virus production per cell was similar in both systems. The number of cells per area unit in confluent cultures was initially lower in the microcarrier culture but subsequently increased. Two to three weeks post inoculation the virus yield per area unit in the microcarrier system was half of that of the conventional culture. The lower cell density per area unit in the microcarrier system was compensated by the large growth area that could be maintained in a single vessel and the total production of virus was substantial. Weekly harvests of medium with HAV antigen titres around 10(-2) contained antigenic material sufficient for several thousands of anti-HAV IgM tests. Propagation of HAV in microcarrier cell cultures thus seems a safe and simple way to produce large amounts of HAV

    Continued transmission of hepatitis B and C viruses, but no transmission of human immunodeficiency virus among intravenous drug users participating in a syringe/needle exchange program

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    The virological efficacy of a syringe/needle exchange program was evaluated in a cohort incidence study. Of 698 intravenous drug users (IVDUs) initially recruited, 15 (2.1%) were HIV-positive at baseline. Adequate follow-up was possible in 515 (74%) and showed no new cases of HIV infection during a median of 31 months. Most IVDUs had been previously exposed to HBV (anti-HBc-positive 70.1%) and HCV (anti-HCV-positive 90.7%). Of those 159 IVDUs negative at baseline for anti-HBc and/or anti-HCV, 56 (35%) seroconverted to one or both viruses during follow-up, corresponding to 11.7 seroconversions/100 y at risk for HBV and 26.3 seroconversions/100 y for HCV. Multiple logistic regression analysis showed hepatitis seroconversion to correlate with imprisonment during the study (OR 2.2; 95% CI 1.04-4.74), absence of drug-free periods (OR 5.7; CI 1.44-22.3) and frequent syringe/needle exchanges (OR 1.31; CI 1.02-1.7). The absence of HIV spread was probably partly due to the low prevalence of HIV-infected IVDUs in the city. Despite free syringes and needles, both HBV and HCV continued to spread at high rates. Nevertheless, syringe/needle exchange programs, coupled with monitoring of serostatus provide good surveillance and are valuable for further assessment of remaining risks

    Influence of twenty potentially antiviral substances on in vitro multiplication of hepatitis A virus

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    A multiwell tissue culture system was developed to study the influence of various substances on hepatitis A virus (HAV) propagation. A panel of 20 substances of different structure types, each with known effect against at least some viruses, was studied at a concentration of 100 microM. Three substances showed reproducible inhibition. The strongest inhibitor, arabinosylcytosine, also produced cytotoxic changes in cells down to a concentration of 1 microM, and its effect was considered as nonspecific. Amantadine and ribavirin showed a moderate effect at 100 microM. A stronger inhibition was seen at 250 and 500 microM, doses that are toxic and impractical for clinical use. Although no promising candidates for antiviral treatment of hepatitis A have emerged from the present study, the assay model described here would seem useful in the screening of substances with inhibitory effects on HAV

    Enhancement of hepatitis A propagation in tissue culture with 5,6-dichloro-1-beta-D-ribofuranosylbenzimidazole

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    The adenosine analog 5,6-dichloro-1-beta-D-ribofuranosylbenzimidazole (DRB) was found to increase the production of hepatitis A (HAV) antigen in two monkey kidney cell lines (Frhk-4 and Vero cells). DRB, a known inhibitor of the synthesis of messenger RNA, caused moderate changes in cell morphology. However, Frhk-4 cells could be maintained for several weeks at 80 microM of DRB, the concentration that caused maximal enhancement on HAV. DRB should be present from about the time of virus inoculation and its strongest effect was seen at low multiplicities of infection. Using radioimmunofocus assay it could be shown that DRB increased the amount of infectious virus. DRB treatment was applied in primary isolation of HAV from feces. In nine of ten strains HAV antigen expression was strongly increased and in six of the ten strains infectivity of harvested material increased by one 10log or more. DRB thus seems to be a useful enhancer of HAV growth in tissue culture

    Antibody to hepatitis-C-virus-related proteins in sera from alanine-aminotransferase-screened blood donors and prospectively studied recipients

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    A prospective study of posttransfusion non-A, non-B hepatitis was conducted in Malmo, Sweden, in 1984-1985, in which donors were alanine aminotransferase (ALT) screened but not ALT selected. Among 741 patients studied at 0, 6, and 12 weeks after transfusion, 13 developed non-A, non-B hepatitis, and these were further followed up. Stored sera from the 13 hepatitis patients and their 123 donors were tested for anti-hepatitis C virus (HCV) by ELISA and if positive, analyzed by recombinant immunoblot assay (RIBA). All ALT-elevated blood units (n = 301) and a similar number of ALT-normal units were also tested. Only 4/13 patients with non-A, non-B hepatitis seroconverted to anti-HCV, all with ALT peaks greater than 10 times the upper normal. All seroconversions occurred within 5 months after transfusion and could be confirmed by RIBA. Hepatitis C in recipients occurred both after transfusion of blood that was strongly positive, weakly positive, and/or negative for anti-HCV by ELISA. In donors grouped by ALT levels, the anti-HCV prevalence varied between 0.4 (normal ALT) and 14% (ALT elevated greater than or equal to 2 times). Of the total of 9 donor units positive by ELISA, only 5 were confirmed by RIBA. Of the 5 recipients of the RIBA-positive blood units, 3 went into hepatitis, 1 remained normal at 10.5 weeks, and 1 showed a slight, transient ALT elevation at week 12. The recipients of ELISA-positive but RIBA-negative blood remained healthy

    Hepatitis E virus infections in patients with acute hepatitis non-A-D in Sweden

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    A total of 12 patients previously treated for acute hepatitis of unknown aetiology were retrospectively found to be anti-hepatitis E virus (HEV) IgG-positive. Four patients were anti-HEV IgM- and IgG-positive consistent with an acute HEV infection. All 4 had travelled to or were immigrants from HEV-endemic countries. One anti-HEV IgM-negative patient seroconverted from anti-HEV IgG-negative to positive and 3 from anti-HEV IgG-positive to negative in 2 consecutive serum samples. Of the remaining 4 patients without anti-HEV IgM, 3 had a history of recent travel to an HEV-endemic country. Most patients were young adults and all but 1 recovered from the hepatitis. One patient with a fulminant hepatitis was anti-HEV IgG-positive when tested 4 months after a journey to Turkey. She died from her fulminant hepatitis shortly after admission. All the other patients but 1 normalized their serum liver enzymes within 1-2 months after the onset of disease

    Antibody to a hepatitis C virus related protein among patients at high risk for hepatitis B

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    Anti-HCV prevalence in treated hemophiliacs, their heterosexual partners, intravenous drug addicts and homosexual men was studied. In hemophiliacs and many of the intravenous drug addicts, greater than or equal to 2 sera drawn 1-18 or 1-17 years apart were available. Anti-HCV testing was performed by ELISA (Ortho). Among patients with severe and moderate hemophilia A, 87% (98/112) were positive for anti-HCV at least once and among patients with severe and moderate hemophilia B, 83% (24/29) were positive for anti-HCV. Seroconversion to anti-HCV was observed in 21% of hemophilia patients. In hemophilia A, HCV infection generally occurred during the first years of life and in hemophilia B somewhat later. Loss of anti-HCV antibody was seen in 12% (17 patients). The rest, 54% (76 patients) were seropositive in first and last samples. All 12 tested spouses to anti-HCV positive men were anti-HCV negative. 80% of the drug addicts (137/172) were seropositive for anti-HCV. In those with greater than 1 serum tested, 8% were consistently negative and 68% consistently positive. 21% seroconverted to anti-HCV while 3% lost antibody. 10% (22/211) of homosexual men were anti-HCV positive. Intravenous transmission of HCV thus seemed highly efficient whereas sexual transmission was much less efficient
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