Impact of screening donor blood for alanine aminotransferase and antibody to hepatitis B core antigen on the risk of hepatitis C virus transmission

The transfusion-related risk of transmission of hepatitis C virus (HCV) was evaluated in France for the periods before and after exclusion of donor blood units with the surrogate markers elevated alanine aminotransferase (ALT) levels and antibody to hepatitis B core antigen (anti-HBc). A total of 1,412 blood recipients undergoing surgery were followed up prospectively in the period from 1986 to 1989. The stored serum samples were tested for antibodies to HCV by an enzyme immunoassay (EIA) and the result in reactive sera confirmed by a recombinant immunoblot assay (RIBA). The risk of HCV transmission was estimated by the maximum likelihood method for a subpopulation of 892 recipients divided into three groups. Of 55 (3.9%) EIA positive patients, 56.4% were found to be positive prior to transfusion. HCV seroconversion (positive RIBA) occurred in 22 patients (1.6%). The risk of HCV transmission per 1,000 transfused blood units decreased significantly from 4.11 in Group 1 (receiving non-screened blood) to 3.43 in Group II (receiving ALT screened blood) and to 1.40 in Group III (receiving ALT and anti-HBc screened blood). These results demonstrate that screening of donors for surrogate markers had reduced the risk of HCV transmission before the introduction of a systematic anti-HCV screening policy in France in March 1990.

Quantitation of immunoglobulin classes and subclasses of autoantibodies bound to red cells in patients with and without hemolysis

The concentration of IgG, IgA, and IgM, as well as IgG subclasses, was measured by an enzyme-linked immunosorbent assay in autoantibodies eluted from red cells (RBCs); the number of molecules of each isotype per RBC was calculated. Three groups were analyzed: Group 1 included 23 patients with autoimmune hemolytic anemia (AIHA) associated with warm autoantibodies of IgG class; Group 2 included 11 patients without anemia but with a positive direct antiglobulin test (DAT); Group 3 included 10 healthy DAT-negative subjects. The mean number of IgG molecules per RBC in Group 1 (920) was about three times that in Group 2 (306) and about 17 times that in Group 3 (54). The range of RBC-bound IgG showed an overlap between the two groups of patients. The mean number of IgM and IgA molecules per RBC was low in the three groups. IgG1 predominated in all groups except in two patients with AIHA, in whom IgG3 made up at least 50 percent of total IgG. The mean number of IgG1, IgG2, and IgG4 molecules per RBC in Group 1 was about three times that in Group 2, whereas the mean number of IgG3 molecules per RBC was 10 times as high (p < 0.001). It follows that IgG3 was more common in patients of Group 1, but it was also detected in patients of Group 2.

IgA cold agglutinins recognize Pr and Sa antigens expressed on glycophorins

Three cases of IgA kappa cold agglutinins (CAs) were studied. One had anti-Pr1 specificity, one had anti-Pra, and one had anti-Sa. The CAs recognize O-glycans of glycophorins. The findings supplement previous data on anti-Pr1 specificities of four IgA kappa CAs. Because all IgA kappa CAs described recognize O-glycans of glycophorins, a close association between the CA IgA isotype and specificities for O-glycans becomes apparent. It is unlikely, however, that the striking association reflects interrelations between IgA CA structure and specificity, because anti-Sa specificity and all anti-Pr subspecificities were originally defined with IgM CAs.

[Transfusion and AIDS]

The possibility of transfusion-induced HIV infection by some blood components and plasma derivatives has been recognized since 1982. The implementation of preventive measures has virtually eradicated the risk of HIV transmission by some blood products and dramatically reduced this risk with other blood products. However, the problem remains unresolved in those parts of the world which have a high prevalence of HIV infection and lack effective blood transfusion systems based on voluntary non-remunerated donors. The extremely low residual risk which in Western countries may still be associated with transmission of labile blood components should neither be denied nor unduly exaggerated. The measures currently in use to try and eradicate this risk consist of improvements in the quality of screening tests and of self-exclusion or questionnaire-based deferral of blood donors who have potentially been exposed to viral contamination. The latter challenge can only be faced through efficient information of prospective donors by physicians, public educators and mass media.

[Performance of Pall filters (RC 100 and PL 100) for the removal of leukocytes from red-cell concentrates and platelets]

20 red cell concentrates (buffy-coat not removed), 5 pools of 5 and 5 pools of 10 standards plateles concentrates, as well as 5 single donor platelet concentrates obtained through Haemonetics V50-1 cytoplasmapheresis procedure, were filtered, within 48 hours after donation, using RC 100 and PL 100 blood filters developed by Pall Company. Using the RC 100 filter on red cell concentrates, the rate of leukocyte removal exceeded 99% of the initial values. The residual leukocyte count per unit was 5.8 +/- 3.4 10(6). Leukocytes in red cell concentrates filtered after a previous one on the same filter numbered 18.6 +/- 8.9 10(6). The rate of platelet removal exceeded 97% of the initial amount. Red cell loss was 6 +/- 9% or 4 +/- 3% of a single or a subsequent unit were filtered respectively. Using the PL 100 filter on platelet concentrates, the rate of leukocyte removal exceeded 88% of the initial values. Residual leukocyte counts were 1.4 +/- 0.4 10(6), 6.2 +/- 3.8 10(6) and 1.4 +/- 0.8 10(6) respectively in 6-unit pools, 10-unit pools and machine prepared platelet concentrates. The average platelet loss was 15%. There was no evidence of alteration in the qualitative parameters of red cells or platelets. The filters were easy to handle and the time needed for the whole filtration process was remarkably short.

[Immune hemolytic anemia induced by drugs]

Drugs may induce immune destruction of red blood cells through either autoantibody formation or antibody formation against the drug or its metabolites. In the former scheme the drug is believed to induce autoimmunization by causing some central dysregulation of the immune system the mechanism of which is still unclear. In the latter, data have been accumulating during the last decade pertaining to clinical manifestations, incriminated drugs, and immunohematologic diagnosis. The sharp specificity and individual variations of drug specific antibodies as well as the recognition of the receptor role of red cell blood group antigens explaining the involvement of red cells in drug-antidrug complexes are among the recent achievements in the knowledge of these anemias.

[Autoimmune hemolytic anemia]

Autoimmune hemolytic anemias are a heterogenous group of disorders as evidenced by the multiple forms and classifications they have been commonly subjected to: acute or chronic, idiopathic or symptomatic, clinically latent or expressed, due to warm or cold autoantibodies. This work attempts to give an overview and synthesis of recent achievements in the knowledge of these syndromes within clinical, immunohematologic and pathophysiologic fields. In contrast, little progress has been made in the therapeutic measures the efficacy of which depends on the same variables as more than a decade ago.

[Prevalence of anti-HIV antibodies in immunoglobulins recipients]

Seven hundred and forty subjects who, between 1980 and 1985, had received intravenous or intramuscular injections of immunoglobulins (Ig) prepared by Cohn fractionation of plasma pools from more than 2000 donors were investigated for anti-HIV antibodies. Anti-HIV antibodies were detected in only one subject, a female drug addict and therefore belonging to a group at high risk of AIDS. In contrast with the huge amounts of Ig received by the remaining 739 subjects (976 litres intravenously, 128 litres intramuscularly), this young woman had only received 10 ml of anti-HBs Ig intramuscularly. The wide scattering in both space and time of these recipients of Ig and the prevalence of anti-HIV antibodies among blood donors in France (0.7 per 1000 in 1985) suggest that all the batches studied (over 100) were contaminated by HIV. The absence in these subjects of seropositive reaction ascribable to the injections of Ig confirms that Cohn fractionation inactivates the virus, as demonstrated in vitro. It is concluded that recipients of Ig prepared from plasma pools not tested for the absence of anti-HIV antibodies should not be regarded as a group at risk of AIDS.

Blood group antigens on fetal red cells obtained by umbilical vein puncture under ultrasound guidance: a rapid hemagglutination test to check for contamination with maternal blood

Seventy-two fetal blood samples obtained by umbilical vein puncture under ultrasound guidance for prenatal diagnosis and monitoring purposes were tested for the expression of 38 blood group antigens. The gestational age at sampling ranged from 18 to 34 wk with 76% of fetuses between 20 and 25 wk. Compared to adult red blood cells, the following antigens showed either abnormally decreased frequency, or significantly reduced expression: A, B, A1, H, Lua, Lub, Lea, Leb, P1, P, and I. Selected anti-I and anti-i cold agglutinins, active at room temperature, were used at appropriate dilution, in a rapid slide or spin test to check for possible mixture of the sample with maternal blood and were shown to detect contaminations up to 5%. The test has proved particularly helpful for immediate and in process assessment of foetal origin of the sampled blood.

[Use of red cells of patients with paroxysmal nocturnal hemoglobulinuria for the detection of hemolyzing antibodies]

90 serum samples from patients with cold agglutinin syndrome were tested for the presence of complement dependent hemolysins, against normal donor red cells versus red cells from patients with paroxysmal nocturnal hemoglobinuria. Hemolysins could be found only in 50% of samples in the first but in up to 95% of samples in the second test configuration. The difference in sensitivity was still more pronounced when protease untreated red cells were used: 1 weak versus 64 strong reactions. The high performance of PNH red cells in detecting hemolysins is specifically observable in any patient with this disease, and should be utilized as a useful diagnostic tool to reveal hemolysins otherwise undetectable by conventional immunohematologic methods.

Drug induced red blood cell autoantibodies co-developed with drug specific antibodies causing haemolytic anaemias

Four individuals with anti-glafenine, anti-latamoxef and anti-teniposide antibodies were found to have an associated red blood cell autoantibody. The two components could be separated by selective absorption and showed distinct time course patterns. In three patients a well-defined blood group antigen was recognized as the receptor for both auto- and drug specific antibodies. Similarities between this type of immune response to drugs and the well-known hapten and carrier specificities developed in animals immunized by hapten-carrier conjugates are discussed.

[In vitro evaluation and study of the survival of erythrocytes preserved in a saline-adenine-glucose-mannitol medium for 35 days]

The saline-adenine-glucose-mannitol (SAGM) solution for resuspension of red cells was evaluated on 30 blood units tested over 42 days and compared to 5 red cell concentrates collected on the conventional CPD medium. Total and extra-cellular hemoglobin, potassium, pH, ATP and DPG concentrations, osmotic fragility, schizocyte formation, and red cell antigenicity were studied through the storage period. Chromium survival studies of autologous donated red cells were performed in 10 donors. Red cell concentrates resuspended in SAGM solution showed at the 35th day of conservation at 4 degrees C, a mean storage hemolysis of only 0.66%, an ATP concentration of 67% of the initial value, a schizocyte proportion of less than 1.5%, a mean 24 hour posttransfusion viability of 88.33% and a mean red cell T 1/2 survival of 25 days 10 hours. No alteration of common blood group antigens could be found after storage of red cells for 42 days.