It is feasible to incorporate NAT-based screening of mini-pools into the routine virus diagnostics of a large blood transfusion service. It remains to be determined whether screening blood donations by NAT will indeed increase the safety of blood supply.

Platelet concentrates prepared from buffy coats may be virtually free of cytokines (IL-1 beta, IL-6, IL-8, and TNF) during 5 days of storage. Filtration is not required to reduce the recipient's cytokine exposure via such platelet concentrates.

The risk of transmitting hepatitis C by blood transfusion is low. Additional tests to shorten the window period to detect antibodies to HCV might increase the safety of blood transfusion.

The contribution of hepatitis C virus (HCV) infection to liver disease after bone marrow transplantation (BMT) was retrospectively evaluated in 61 patients treated with BMT. HCV genome, as well as antibodies to HCV, was analyzed in sera collected before and serially after BMT. Six patients had been infected with HCV before BMT and three patients acquired the infection during or shortly after BMT. All patients infected before BMT died within 10 weeks after transplantation. Five of these six patients (83%) died of veno-occlusive disease (VOD), compared with nine of 52 patients (17%) not infected with HCV (P < .005). Risk factors for VOD other than HCV were not more prevalent in these patients compared with uninfected patients. Parallel to the development of VOD, replication of HCV increased, as demonstrated by rising concentrations of viral RNA in serum. HCV infection acquired during or after BMT caused only mild acute hepatitis C, which progressed to chronic hepatitis C in one patient surviving 10 years after BMT. These data suggest that patients with liver disease caused by HCV infection are at high risk of developing lethal VOD after BMT.

In this study we describe the establishment of two hybridoma cell lines secreting human monoclonal antibodies to the 22-kD nucleocapsid protein (core, p22) of the hepatitis C virus (HCV). For this purpose we isolated B lymphocytes from an anti-HCV positive blood donor and infected them with Epstein-Barr (EBV). We obtained several lymphoblastoid cell clones secreting antibodies to the recombinant HCV core protein. The B-cell cultures were oligoclonally expanded and two of them were fused with the (mouse:human) heteromyeloma cell line K6H6/B5. The resulting stable hybridomas produce antibodies of the IgG1/kappa (U1/F10) and the IgM/kappa (Ul/F11) isotype reacting specifically with the recombinant core protein p22. To identify the epitopes recognized by these antibodies we synthesized overlapping peptides (13-mer and 6-mer) from the amino terminus of the core amino acid sequence. Antibody reactivity to these peptides was analyzed in an immunoblot assay. Finally, we were able to define a linear epitope recognized by the Ul/F10 antibody on the nucleocapsid protein. The antibody shows specificity to the sequence N-VYLLPR-C, which corresponds to the amino acids 34-39 of the core sequence.

We extended the time of keeping whole blood at 20-24 degrees C to 15 h (overnight) after phlebotomy for preparing platelet concentrates. We have evaluated the in vitro characteristics of platelets and blood cells prepared from whole blood drawn into CPD-AD, an anticoagulant containing 0.4 mM adenine and 1.5 times more dextrose than CPD. We studied in vitro red cell and platelet function of blood cooled either within 4 h after collection or after a 15-hour delay. In vitro platelet function measured as hypotonic shock reaction, aggregation response to ADP and collagen and 14C-serotonin uptake were not significantly different after preparation and after a 5-day storage period. Units held at room temperature for 15 h after blood collection exhibited a level of 2,3-DPG that was 45% of that exhibited by red cells held for 15 h at 1-6 degrees C. All other in vitro parameters of red cell concentrates measured during 35 days of storage were not significantly different. Based on these in vitro data blood drawn into CPD-AD might be kept up to 15 h at room temperature prior to refrigeration in order to prepare platelet concentrates.

Three different synthetic media without glucose were studied for platelet storage. The first medium contained acetate and gluconate. The second contained acetate, gluconate and citrate. Finally the third contained phosphate and mannitol. The purpose of the study was to investigate whether there were differences among the various media in terms of preservation of platelet quality. Pools of platelet concentrates were prepared from buffy coats. In vitro function and metabolic parameters were measured during 5 days of storage in these additive solutions as well as in plasma. Platelet aggregation, hypotonic shock response and release of beta-thromboglobulin, platelet factor 4 and lactate dehydrogenase of the cytosol were equivalent in the media containing acetate compared to plasma storage. In vitro platelet functions and pH in these two media were better preserved compared to the medium with phosphate and mannitol. In addition bacteriological studies using platelets suspended in additive solutions or in plasma were carried out. Carryover of 20% of plasma to the synthetic media necessary for successful platelet storage in these additive solutions allows bacteriological growth. As shown, inoculation of 1 colony/ml Staphylococcus epidermidis leads to 10(6)-10(7) organisms/ml after 5 days of storage.

To examine the consistency and comparability of anti-hepatitis B core antigen (anti-HBcAg) assays, four blood donation centers of the Red Cross in the Federal Republic of Germany tested 4,080 unselected blood donors with six different tests in parallel. Confirmation testing of reactive samples was done in the National Reference Center for Viral Hepatitis. Depending on the test kit used, 4.1 to 9.9% of serum samples were initially positive and 2.9 to 7.5% were repeatedly positive. Sixteen percent of serum samples were positive in at least one test but only three percent were positive in ail six tests. Statistical analysis of frequency distribution of optical densities for each test suggested that there should be a correction of the cutoff values. This reduced the number of false-positive results by half, but a significant proportion of discrepant results could not be resolved. The lack of specificity and consistency requires cautious interpretation of isolated anti-HBcAg results in clinical specimens. Screening of predominantly anti-HBcAg-negative populations (e.g., blood donors) by the current anti-HBcAg test kits will almost necessarily give unsatisfactory results.