Serological markers of posttransfusion hepatitis C viral infection.

Serological markers for hepatitis C virus (HCV) infection were measured in serial samples from 14 posttransfusion chronic non-A, non-B hepatitis patients by a semiquantitative dot blot immunoassay. The assay detected antibodies to HCV by use of recombinant proteins that represent putative HCV capsid (core), nonstructural protein 3 (NS3) (33c), and NS4 (c100) epitopes. Seroconversion to anti-HCV antibodies (anti-HCV) was detected in all patients. The average time to active antibody production detected by any of the recombinant proteins was 13.8 (range, 3.6 to 22.0) weeks posttransfusion or 4.6 (range, -4.5 to 13.4) weeks after the first biochemical marker of illness. Anti-HCV were detected earliest by the core antigen in most cases; however, the patterns of anti-HCV responses varied significantly among individuals. Overall, the addition of the core and NS3 antigens to the assay enabled the detection of the antibody response 4 to 5 weeks earlier than did the addition of the c100 antigen, the sole antigen used in current screening tests in the United States. Passively transferred antibodies were detected by at least one antigen in early posttransfusion samples from 12 patients and decayed below detectable levels for all antigens in only 2 patients. Antibodies to all three gene products were evident in the last sample from all five patients monitored for greater than 3 years from transfusion indicating the persistence of antibodies in patients with chronic illness. Our data show that the period following the onset of hepatitis during which anti-HCV are not detected by current screening assays can be greatly shortened by the detection of anti-HCV responses by a combination of core, NS3, and c100 antigens.

The use of a recombinant immunoblot assay in the interpretation of anti-hepatitis C virus reactivity among prospectively followed patients, implicated donors, and random donors.

Samples from prospectively followed recipients, their respective donors, and a cohort of random donors were used to evaluate the specificity and efficacy of a recombinant immunoblot assay (RIBA) as an adjunct to anti-hepatitis C virus (HCV) testing by enzyme immunoassay (EIA). RIBA reacted (RIBA+) in 100 percent of patients who developed hepatitis associated with anti-HCV seroconversion documented by EIA and in 100 percent of the EIA-positive (EIA+) donors implicated in these cases. In contrast, RIBA reacted in none of 10 recipients who were EIA+ but did not develop hepatitis, in none of 7 EIA+ patients with hepatitis B or cytomegalovirus infection, in 33 percent of EIA+ donors who were not implicated in hepatitis transmission, and in 37 percent of EIA+ random donors. Hence, the vast majority of EIA+ individuals who have ancillary evidence of HCV infection react on RIBA, whereas the majority of EIA+ individuals in low-risk settings do not react (RIBA-negative, or RIBA-). There was a strong association between RIBA reactivity and the presence of a surrogate marker (elevated alanine aminotransferase [ALT] and/or antibody to hepatitis B core antigen); 43 percent of RIBA+ implicated donors had a surrogate marker as compared to none of 14 EIA+, RIBA- donors. Among EIA+ random donors, 77 percent of those with a surrogate marker were RIBA+, as compared with 29 percent of those without a surrogate marker. In addition, in EIA+ donors, RIBA reactivity correlated with the extent of ALT elevation; 86 percent of those with an ALT greater than 135 IU per L were RIBA+ compared with 18 percent of those with an ALT less than 30 IU per L.(ABSTRACT TRUNCATED AT 250 WORDS)

Hepatitis C infection in children with hemophilia A and B.

Antibodies to hepatitis C virus (anti-HCV) were quantitated in stored sera from selected groups of hemophilic children (less than or equal to 18 years of age). During the period 1987 to 1989, seropositivity rates were as follows: untransfused hemophiliacs 0% (0 of 11 cases), hemophiliacs treated exclusively with vapor-heated factor VIII or IX concentrates 0% (0 of 9 cases), hemophiliacs treated only with cryoprecipitate or single donor blood products 0% (0 of 9 cases), and hemophiliacs regularly treated with unheated or dry heat-treated factor VIII or IX concentrates 95% (21 of 22 cases). Corresponding alanine aminotransferase (ALT) results were similar: values were always below the upper limit of laboratory normal (40 U/L) in untransfused hemophiliacs, hemophiliacs treated with vapor-heated factor concentrates, or those who received only cryoprecipitate or single donor blood products. By contrast ALT values were greater than 40 U/L in 82% (18 of 22 cases) of hemophilic children regularly infused with unheated or dry heat-treated factor concentrates. Three conclusions are drawn from this data: (1) HCV is a major cause of chronic hepatitis in multitransfused hemophilic children, (2) unheated and dry heat-treated clotting factor concentrates carry a very high risk of transmitting HCV infection, and (3) clotting factor concentrates inactivated by vapor heating carry a very low and perhaps zero risk of transmitting HCV infection. These findings are of therapeutic significance for previously untransfused hemophiliacs susceptible to HCV infection.

Transfusion-transmitted HTLV-I/II infection in patients undergoing open-heart surgery.

Sera from 5,244 blood donations collected between 1979 and 1987 were screened for antibody to HTLV-I with an enzyme immunoassay (EIA) whose result was confirmed with a two-step procedure including Western blot (WB) and radio immunoprecipitation. Of 20 repeatedly reactive samples, two were confirmed positive for HTLV-I infection. These blood units were transfused to patients undergoing cardiac surgery. Both recipients of the confirmed anti-HTLV-I positive units were infected with HTLV-I as evidenced by antibody seroconversion. In contrast, six recipients of EIA positive, WB indeterminate blood and nine recipients WB negative blood were not infected with HTLV-I. These results confirm a low prevalence of HTLV-I infection in US blood donors, the capacity of infected units to transmit the virus to recipients, and the importance of an appropriate confirmatory assay.

What do western blot indeterminate patterns for human immunodeficiency virus mean in EIA-negative blood donors?

To investigate the specificity of western blot indeterminate (WBi) patterns for antibodies to the human immunodeficiency virus type 1 (HIV-1), 100 enzyme immunoassay (EIA) negative donors from whom prospectively obtained recipient sera were available were tested by WB. 20 were WBi, with p24 being the predominant (70%) and generally the only band. Among recipients of WBi blood, 36% were WBi in their 6 month post-transfusion sample, but so were 42% of a control population that had received only WB-negative blood. When serial samples from recipients with a WBi pattern were tested on two occasions, only 35% of results were reproducible. No reciepient of WBi blood became EIA positive, true positive for WB, positive for HIV-1 antigen, or positive for EIA reactivity against recombinant p24 or gp41. The polymerase chain reaction was negative for gag and env HIV-1 sequences in all donors and recipients. Thus WBi patterns are exceedingly common in randomly selected donors and recipients and such patterns do not correlate with the presence of HIV-1 or the transmission of HIV-1 from donor to recipient.