U.K. multicentre study on blood donors for surrogate markers of non-A non-B hepatitis. Part I: Alanine transferase and anti-HBc testing.

Blood samples from 9,215 blood donors in three U.K. centres (North London, Bristol and Manchester) were tested for their alanine aminotransferase (ALT) level and the presence of anti-HBc and anti-HCV. This paper presents the results of the ALT and anti-HBc tests. The prevalence of ALT > 45 IU/l was 3.1% overall (North London 3.06%, Bristol 4.56% and Manchester 1.97%). Manchester results were skewed by the methodology used for ALT measurement, highlighting the need for standard test methods. Anti-HBc was detected using the Wellcome enzyme-immunosorbent assay (EIA) and confirmatory testing was performed using a radioimmunoassay (RIA) and the Corecell haemagglutination assay. Repeat reactive rates were 0.9, 0.79 and 0.94% for North London, Bristol and Manchester, respectively, with an overall rate of 0.9%. The confirmed positive rate was 0.73, 0.53 and 0.65% for the three centres with an overall rate of 0.63%. Donors with an ALT > 45 IU/l, or with confirmed anti-HBc, were interviewed with a medical questionnaire for risk factors. The major contributing factors in donors with a raised ALT were alcohol consumption and obesity.

Serum alanine aminotransferase (ALT) and gamma-glutamyltransferase (gamma-GT) activities in north London blood donors.

Serum alanine aminotransferase (ALT) and gamma-glutamyltransferase (gamma-GT) activities were measured in over 2000 north London blood donors. The results were compared with those from the United States. The percentage of the total donor population with ALT activities above 40 IU/l in 1986 was greater than that found in our earlier studies in 1973 and 1982 (4.6% compared with 2.8% and 3.1%, respectively). There was a noticeable difference in the ALT distribution between male and female donors: mean +2.25 SD for male donors was 55.3 IU/l, while that for female donors was 30.8 IU/l at 37 degrees C. In stability studies the optimal temperature for short term storage (10 days) was 4 degrees C (6.4% loss of activity after 10 days). Surprisingly, storage at lower temperatures (-35 degrees C and -80 degrees C) resulted in greater loss of activity.

Leukocyte-depleted blood. A comparison of filtration techniques.

Febrile transfusion reactions due to leukoagglutinins are commonly seen in multitransfused patients. It has been suggested that reduction of the number of leukocytes per transfusion to 0.5 x 10(9) or less would prevent nonhemolytic febrile transfusion reactions in the majority of patients. Therefore, we have compared the ability of several filters to reduce the leukocyte content of stored whole blood drawn into citrate-phosphate-dextrose. The leukocyte absorption filters, Imugard IG500 and Erypur, produced 98.3 +/- 2.4 and 98.3 +/- 1.7 percent leukocyte depletion, respectively. The leukocyte adherence filter, Leuko-Pak, produced a depletion of 54.6 +/- 14.7 percent. The microaggregate filters, Biotest MF10B Microfiltration set, Ultipor Blood Transfusion Filter SQ40S, and Travenol 20 micron High Capacity Transfusion Filter, produced 37.5 +/- 10.8, 13.3 +/- 11.2, and 44.5 +/- 11.3 percent leukocyte depletion, respectively. It would appear that of the filters tested, the Imugard IG500 and the Erypur are the only filters which can invariably reduce the absolute number of leukocytes in a unit of stored whole blood to below 0.5 x 10(9).

Leucocyte-depleted blood: a comparison of cell-washing techniques.

Non-haemolytic febrile transfusion reactions are common in multi-transfused patients. It is generally accepted that the majority of these reactions occur when more than 0.5 x 10(9) leucocytes are transfused. Values equal to or lower than this threshold, which we have called for convenience the critical antigenic load for leucocytes (CALL), can be achieved by decreasing the leucocyte content in one unit of whole stored blood by about 80%. We have compared the efficiency of leucocyte depletion of whole stored blood, using fixed-speed centrifugation (Haemonetics Model 15 and Model 115 cell washer), variable-speed centrifugation (Dideco Progress 90 Cell Separator), and serial centrifugation (IBM 2991 Blood Cell Processor. Fixed-speed centrifugation was least effective in depletion leucocytes; a reduction of 25 and 60% was achieved using the Haemonetics Model 15 and Model 115, respectively. Variable speed and serial centrifugation produced more satisfactory results with leucocyte depletions of 82 and 89% using the Dideco Progress 90 Cell Separator and the IBM 2991 Blood Cell Processor, respectively. Platelet depletion of over 90% was achieved with all the cell washers, except the Haemonetics Model 15. Red cell losses varied from 3 to 30%. It seems unlikely that consistently high (over 90%) leucocyte depletion can be obtained using cell-washing techniques without associated high red cell losses.

Liver enzyme concentrations as measure of possible infectivity in chronic asymptomatic carriers of hepatitis B.

Fifty-two British-born blood donors who were chronic carriers of hepatitis B surface antigen (HBsAg) were tested for the presence of hepatitis B e antigen (HBeAg) and antibody to HBeAg by an immunoradiometric assay. The presence of HBeAg was closely associated with a slight rise in serum liver enzyme concentrations, a high HBsAg titre, and male sex. We suggest that the finding of persistently raised serum liver enzyme concentrations in an asymptomatic HBsAg carrier might be useful as a likely indicator of HBeAg and high infectivity.