Transfusion transmitted infectious diseases

The best means to reduce transfusion-transmitted infections is to start with volunteer, unpressured, altruistic blood donors. Careful screening and use of a number of sensitive tests to detect asymptomatic carriers of various infections make blood transfusion quite safe today. However, there will never be a zero risk blood supply. Therefore, additional efforts should be made to transfuse patients appropriately as we seek safer alternatives to traditional transfusions. In the meantime, we should congratulate ourselves for having a very safe and good blood supply, which can help so many patients.

Chronic hepatitis B virus infection in an anti-HBc-nonreactive blood donor: variant virus or defective immune response?

Viral sequence and host immune response were investigated in an unusual, asymptomatic chronic hepatitis B virus carrier (human leukocyte antigen type A24, Bw61, Bw62, Bw6, DRw11, DRw52, DQw7) who was consistently nonreactive for antibody to HBc and had a normal ALT level over a 5-yr study period. The precore and core region DNA sequences of virus isolated from his serum had seven silent mutations that resulted in no changes in the amino acid sequence of the adr HBsAg subtype. He had no abnormalities in the number of peripheral blood T or B cells and no HBcAg-specific suppressor T cells. His lymphocytes proliferated in vitro in response to phytohemagglutinin, pokeweed mitogen, Staphylococcus aureus and tetanus toxoid but not to recombinant HBcAg. Unlike other HBsAg carriers and hepatitis B virus-immune individuals, his monocytes did not ingest beads coated with HBcAg. Failure to produce antibody to HBc was not due to an hepatitis B virus variant but to a selective immune system defect in this asymptomatic HBsAg carrier.

Detection of antibodies to human immunodeficiency virus type 2 (HIV-2) in blood donor sera using United States assay methods for anti-HIV type 1

Twelve serum samples from French blood donors that were uniformly reactive in tests for antibody to human immunodeficiency virus type 2 (anti-HIV-2) also were reactive in 92 to 100 percent of tests with three anti-HIV type 1 (anti-HIV-1) enzyme-linked immunoassays currently in widespread use for donor screening in the United States. Supplemental tests for anti-HIV-1 on these anti-HIV-2-reactive samples differed in their responses. All samples reacted in a licensed anti-HIV-1 Western blot, but there was an atypical band near the p41 position, which could be a clue to the fact that this result was a cross-reaction with anti-HIV-2. A recombinant immunoblot gave an indeterminate result for anti-HIV-1 in all 12 samples. A local immunofluorescence assay for anti-HIV-1 reacted with 92 percent of the samples, but a commercial one detected only 58 percent.

Detection of acute hepatitis C virus infection by ELISA using a synthetic peptide comprising a structural epitope

An enzyme-linked immunosorbent assay (ELISA) was developed by using a synthetic polypeptide (SP) whose sequence was derived from the structural region of hepatitis C virus (HCV). Results of several coded panels of sera obtained from volunteer blood donors and patients with apparent non-A, non-B hepatitis and/or hepatitis B virus used in this ELISA were compared with those of a commercially available first-generation C-100 ELISA (using nonstructural HCV antigens), an experimental second-generation C-200/C-22 ELISA (using both structural and nonstructural HCV antigens), and recombinant immunoblot assays RIBA-I and RIBA-II. In the majority of cases, the results obtained with the HCV-SP ELISA correlated well with those obtained by RIBA-II and C-200/C-22 ELISA. In contrast, many samples that were repeatedly reactive in the C-100 ELISA results were nonreactive with RIBA and HCV-SP ELISA. In addition, HCV-SP detected HCV-specific antibody that appeared within a month of infection and coincided with the earliest increase in alanine aminotransferase. In summary, we have developed an ELISA based on a structural HCV synthetic polypeptide, HCV-SP, that has high specificity and sensitivity and is capable of detecting specific antibodies in the acute phase of HCV infection.

Detection of antibody to immunodeficiency viruses by dot immunobinding assay

The dot immunobinding assay (DIA), a modified enzyme immunoassay (EIA), has been demonstrated to be a highly sensitive and specific assay for the detection of antibody to a number of viruses. Different laboratory procedures are available for detecting antibody to the immunodeficiency viruses; however, these procedures require a certain amount of sophisticated equipment and trained personnel. Further, commercial kits for detecting antibody to human immunodeficiency virus, as now available, are not easy to use in the nonlaboratory setting. The DIA, as described herein, may be formatted to test up to 30 serum samples and is designed to be used in the absence of laboratory equipment. To determine the effectiveness of the DIA as a test kit for the detection of HIV and human T-cell leukemia virus type I (HTLV-I) antibodies, the kit was compared with commercial EIA and Western blot (WB; immunoblot) kits. Testing approximately 1,000 human serum samples for HIV antibody by DIA and EIA revealed a total agreement of 98.1%, a specificity of 99.0%, and a sensitivity of 95.9%. For 804 serum samples tested (200 were tested independently in two laboratories), eight results were discrepant: four DIA negatives which were EIA borderline positive and four DIA positives which were EIA negative. Testing the eight discrepant sera by immunofluorescence assay and WB resulted in their being either negative or indeterminate. The four DIA positives were indeterminate by WB. Close agreement was obtained when the remaining sera were compared by DIA, EIA, and WB. Of interest was finding that the DIA results compared favorably with those obtained by WB. Twenty-six suspect HTLV-I-positive serum samples tested by DIA also gave results comparable to those obtained by EIA and WB.

Effects of serial plasmapheresis on serum IgA levels in IgA-deficient blood donors with IgA-suppressor T cells

Seventeen IgA-deficient blood donors, without antibodies to IgA, underwent plasmapheresis four to eight consecutive times at intervals of 8 weeks or less to provide fresh-frozen plasma for patients with anti-IgA. Blood samples, drawn for analysis no more than 1 hour before plasmapheresis and again at the conclusion of each procedure, were analyzed for lymphocyte subpopulations and serum IgA levels. Five lymphocyte subpopulations, including natural killer cells, the suppressor-inducer CD4 subset, the suppressor-precursor CD8 subset, non-major histocompatibility complex (MHC)-restricted cytotoxic T cells, and CD5+ B cells, were all decreased significantly after plasmapheresis (p less than 0.05). In a subgroup of IgA-deficient donors with excessive IgA-suppressor T-cell activity, serum IgA increased to levels exceeding 0.05 g per L following the fourth consecutive plasmapheresis procedure. Serum IgA levels did not similarly increase in IgA-deficient donors without excessive IgA-suppressor T-cell activity or in controls without IgA deficiency. Our study shows the potential, in a subpopulation of IgA-deficient donors who undergo frequent plasmapheresis, for a transient increase in serum IgA to a level no longer considered IgA deficient.

Seroepidemiology of viral infections among intravenous drug users in northern California

Intravenous drug users are frequently exposed to parenterally transmitted viral infections, and these infections can spread to the general population through sexual activity. We investigated the prevalence of serologic markers for human immunodeficiency virus type 1 (HIV-1), human T-cell lymphotropic virus type I/II (HTLV-I/II), hepatitis B virus (HBV), and hepatitis C virus (HCV) in intravenous drug users and their sexual contacts. Of 585 drug users from northern California tested for these serologic markers, 72% were reactive for the antibody to HCV, 71% for the antibody to hepatitis B core antigen, 12% for HTLV-I/II antibodies, and 1% for the HIV-1 antibody. The prevalence of serologic markers for these four viruses correlated with the duration of intravenous drug use, the ethnic group, and the drug of choice. More than 85% of subjects infected with either HCV or HBV were coinfected with the other virus. All persons reactive to HTLV-I/II antibodies had antibodies for either HBV or HCV. Of 81 sexual contacts tested, 17% had evidence of HBV infection while only 6% were reactive for HTLV-I/II antibodies and 4% for the antibody to HCV. None of this group was infected with HIV-1. We conclude that HTLV-I/II and HCV are inefficiently transmitted to sexual contacts while HBV is spread more readily. Programs designed to discourage the sharing of drug paraphernalia, such as needle and syringe exchanges, should decrease the risk of parenterally spread viral infections in intravenous drug users and thus slow the spread of these infections to the general population.

Characterization of a reduction-sensitive factor from human plasma responsible for apparent false activity in competitive assays for antibody to hepatitis B core antigen

Addition of reducing agents to competitive assays for antibody to hepatitis B core antigen (anti-HBc) eliminates apparent false reactivity of specimens obtained from individuals with no prior history of hepatitis B virus (HBV) infection and without other serological markers of HBV infection. We have purified and characterized a reduction-sensitive factor (RSF) isolated from the plasma of several volunteer blood donors. Column fractions were assayed fro anti-HBc by using a highly sensitive chemiluminescence assay with a detection of 0.15 Paul Ehrlich Institut units per ml at 50% inhibition. Gel filtration on Sephacryl S-300 indicated that reductant-sensitive samples possessed anti-HBc activity that was associated with immunoglobulin M (IgM), whereas reductant-stable activity was associated with IgG. Gel filtration followed by metal chelate affinity chromatography resulted in a 55-fold purification and demonstrated that RSF activity copurifies with IgM. RSF was recovered from a recombinant hepatitis B core antigen matrix and shown to be an IgM species by immunoblot. In addition, RSF activity coeluted with IgM protein from anti-mu-chain Sepharose. Discrepancies between enzyme immunoassay and radioimmunoassay procedures for anti-HBc (Corzyme and Corab, respectively: Abbott Laboratories, North Chicago, Ill.) appear to be due to the relative sensitivity of the enzyme immunoassay for IgM anti-HBc (sevenfold greater than the radioimmunoassay using a specific panel). The biological basis for the occurrence of low levels of nonspecific IgM anti-HBc reactivity in individuals not previously exposed to HBV remains to be elucidated.

Prevalence of hepatitis C virus antibodies among patients infected with human immunodeficiency virus

A study was undertaken to determine the prevalence and risk factors for serological evidence of hepatitis C virus (HCV) infection in patients infected with the human immunodeficiency virus (HIV). Tests for anti-HCV antibody were carried out by enzyme-linked immunoassay (EIA) on 101 HIV-infected patients from two university-based outpatient clinics. Anti-HCV antibody reactive samples were tested by using a recombinant immunoblot assay (RIBA) for HCV antibodies. Fourteen of 101 (13.9%) HIV-infected patients were anti-HCV reactive by EIA. Of these 14, only seven were reactive by RIBA: four were intravenous drug users as a sole risk factor for HIV infection; and the remaining three acquired HIV by blood transfusion, contaminated instrument exposure or IV drug use and sexual contact. Acquisition of HIV by sexual activity alone was not associated with HCV infection. It is concluded that HCV infection is found in approximately 7% of a university HIV clinic population. False-positive anti-HCV antibody serology may lead to overestimation of the prevalence of HCV infection. Female sex and intravenous drug use are significantly associated with HCV infection among HIV-infected individuals.

Non-A, non-B hepatitis and antibody to hepatitis C virus

Stored serum samples from the Transfusion-transmitted Viruses Study in the 1970s were tested for the presence of antibody to hepatitis C virus (anti-HCV). Single specimens from five control subjects who did not receive transfusions tested negative for anti-HCV. Of four control subjects who did not receive transfusions and who developed non-A, non-B (NANB) hepatitis after hospitalization, three remained anti-HCV negative; the fourth person with postoperative NANB hepatitis tested anti-HCV positive before the operation. Five transfusion recipients with posttransfusion hepatitis B virus infection remained seronegative; a sixth with NANB hepatitis as well as hepatitis B virus infection had seroconversion for anti-HCV. Five of nine transfusion recipients with NANB hepatitis had anti-HCV seroconversion. These results show that present anti-HCV testing demonstrates an etiologic basis for approximately half of the cases of transfusion-associated NANB hepatitis, particularly those that develop chronicity. Although cases of NANB hepatitis without seroconversion may be explained otherwise, they may be caused by another, presently unidentified, virus.

The natural history of transfusion-associated infection with human immunodeficiency virus. Factors influencing the rate of progression to disease

Patients infected by the human immunodeficiency virus (HIV) as a result of blood transfusions are unique in that their dates of infection are well defined and their medical conditions before infection are known. To characterize the natural history of transfusion-associated HIV infection, we studied 694 recipients of blood from 112 donors in whom AIDS later developed and from 31 donors later found to be positive for HIV antibody. Of the recipients tested, 85 were seronegative, 116 were seropositive, and 19 had AIDS. Of 101 HIV-seropositive recipients followed for a median of 55 months after infection, 54 had Centers for Disease Control Class IV disease, including 43 with AIDS. Life-table analysis suggested that AIDS will develop in 49 percent of infected recipients (95 percent confidence limits, 36 to 62 percent) within seven years after infection. As compared with recipients without AIDS, the 43 recipients with AIDS had received more transfusions at the time of infection (median, 21 vs. 7; P = 0.01). HIV-infected blood donors in whom AIDS developed were grouped according to whether AIDS developed within 29 months (the median) after donation (Group 1) or 29 or more months after donation (Group 2). As compared with the 31 recipients of blood from Group 2 blood donors, the 31 recipients of blood from Group 1 donors were more likely to have AIDS four years after infection (49 percent vs. 4 percent; P = 0.005) and illnesses resembling acute retroviral syndrome (14 of 24 vs. 5 of 22; P = 0.03). We conclude that most recipients of HIV-infected blood become seropositive, that AIDS develops in about half these recipients within seven years, and that the risk may be higher when AIDS develops in the blood donor soon after donation.

Lyme disease--another transfusion risk?

Lyme disease (or Lyme borreliosis) is caused by a spirochetal bacteria, Borrelia burgdorferi. Increased recognition of the disease and increased exposure to the vector (ticks) capable of spreading B. burgdorferi from animal hosts have resulted in a rise in the number of cases of Lyme borreliosis reported in the United States. There are three stages of the clinical course of Lyme borreliosis; however, not all those infected will have typical manifestations of each stage, such as the arthritis of the third stage. Routine blood cultures will rarely document bacteremia and serologic testing is not yet reliable. Early treatment can prevent later stages of Lyme borreliosis. There is evidence that transmission of B. burgdorferi by blood transfusion is possible, but, to date, there has been no documentation of transfusion-associated Lyme borreliosis. Thus, no new recommendations for screening donors to identify possible carriers of B. burgdorferi are suggested at this time.

Prevention of transfusion-associated graft-vs-host disease

Transfusion-associated graft-vs-host disease (GVHD) occurs in certain immunocompromised recipients receiving viable lymphocytes in blood and components. Transfusion-associated GVHD affects the skin, liver, gastrointestinal tract, and most importantly, the bone marrow, and results in death in more than 90% of affected patients. The best means to prevent transfusion-associated GVHD is prophylactic irradiation of blood and components to inactivate contained lymphocytes. A dose of 15 Gy delivered by a self-contained cesium 137 irradiator is sufficient to prevent transfusion-associated GVHD. Engraftment of transfused lymphocytes may occur because of HLA similarity between donor and recipient. The HLA differences, however, then facilitate rejection of the host by the engrafted lymphocytes and thus make easier the development of transfusion-associated GVHD or the Japanese equivalent, postoperative erythroderma.

Antibody to hepatitis B core antigen as a paradoxical marker for non-A, non-B hepatitis agents in donated blood

The relationship between the presence of antibody to hepatitis B core antigen (anti-HBc) in donor blood and the development of hepatitis in recipients of that blood was studied in 6293 blood donors and 481 recipients who were followed for 6 to 9 months after transfusion. Of 193 recipients of at least 1 unit of blood positive for anti-HBc, 23 (11.9%) developed non-A, non-B hepatitis compared with 12 (4.2%) of 288 recipients of only anti-HBc-negative blood (p less than 0.001). Donor anti-HBc status was not significantly associated with the development of hepatitis B in the recipient and was negatively associated with the development of cytomegalovirus hepatitis. The relationship of donor anti-HBc status and the development of non-A, non-B hepatitis in the recipient was independent of transfusion volume and elevated donor transaminase level. Although 88% of anti-HBc-positive blood units were not associated with recipient non-A, non-B hepatitis, calculation of maximal corrected efficacy predicted that exclusion of anti-HBc-positive donors might have prevented 43% of the cases of non-A, non-B hepatitis with a donor loss of 4%. Because of the serious chronic consequences of non-A, non-B hepatitis, surrogate tests for non-A, non-B virus carriers must be seriously considered.

Anti-HTLV-III testing of blood donors: reproducibility and confirmability of commercial test kits

Since 2% of the cases of Acquired Immune Deficiency Syndrome (AIDS) have been attributed to transfusions of blood and blood products, licensed tests to detect antibody to the human T-lymphotropic virus type III (anti-HTLV-III) have been put into practice to reduce the risk of transfusion associated AIDS. Two commercial ELISA kits (Abbott and ENI) were used to test for anti-HTLV-III in 100 coded samples from individuals with AIDS, at high risk for AIDS, or with low risk for AIDS and in 1280 unlinked blood donor serums. From the 100 coded samples, both Abbott and ENI tests identified 51 of 52 coded samples with anti-HTLV-III which were confirmable with Western blot analysis. Initial testing of the donor serums by Abbott's test revealed 20 reactives, of which 5 were repeatably reactive; initial testing by ENI's test revealed 25 reactives, of which 14 were repeatably reactive. However, only 3 donor serums were repeatably reactive by both test kits, out of 17 repeatable reactive by either, and no ELISA positive samples were confirmed by Western blot or IFA. Before a blood donor is notified of "anti-HTLV-III reactivity", tests demonstrating this should be both reproducible and confirmable by at least one additional test.