No abstract

Although the value of HLA matching for the selection of platelet donors for patients refractory to random platelets is beyond doubt, even perfectly matched combinations sometimes fail to give a satisfactory transfusion response. With HLA typing and negative lymphocytotoxicity crossmatches, 35% of the platelet transfusions administered to 15 patients gave disappointing results (29 of 82). Additional crossmatching with the newly developed platelet fluorescence test described in this paper reduced the unexpected transfusion failures to 7% (6 of 82). Five of these failures were observed in one patient. The target of the antibodies detected with this platelet fluorescence test is not yet fully specified. It seems probable that both HLA and platelet-specific non-HLA antibodies were detected. No correlation of the results of platelet transfusions with the presence or absence of leukoagglutinating antibodies was found.

In a prospective study we investigated the development and the course of alloimmunization after leukocyte-depleted red cell and multiple random donor platelet transfusions in 335 patients. Of these 335 patients, who had a negative antibody screening on admission and a negative transfusion history, 69 (21%) developed either transient (n= 18) or permanent (n = 51 ) lymphocytotoxic antibodies, but only 31 patients (9%; 95% confidence limits 6-12%) developed multispecific alloantibodies necessitating HLA-matched platelet transfusions. There was no difference with regard to the development of antibodies and platelet refractoriness between leukemia patients receiving cytostatic treatment and patients with aplastic anemia receiving prednisone and antithymocyte globulin. Females with previous pregnancies developed platelet refractoriness with an increased incidence (χ^2 13.38; p<0.001) compared to females without previous pregnancies, males, and children.

Summary With the aid of four sera which contained leucocyte agglutinins and were obtained from women who had been pregnant, it has been possible to define a di‐allelic leucocyte group, designated leucocyte group Five. The antigen 5a has a gene frequency of 0.181 and the antigen 5b a gene frequency of 0.819. The importance and limitations of cross‐absorption experiments in these studies are discussed. Résumé A l'aide de 4 sérums contenant des agglutinines anti‐leucocytaires qui ont été obtenues chez des femmes ayant eu des grossesses, il a été possible de mettre en évidence un groupe leucocytaire di‐allèlique dénommé groupe leucocytaire Cinq. L'antigène 5a une fréquence de 0,181 et l'antigène 5b une fréquence génique de 0,819. L'importance et les limites d'expérience d'absorption croisée dans ces études sont discutées. Zusammenfassung Mit Hilfe von vier leukoagglutininhaltigen Seren schwanger gewesener Frauen gelang es, eine neue di‐allele Leukozytengruppe zu erfassen, die als Gruppe Fünf bezeichnet wurde. Das Antigen 5a hat eine Genfrequenz von 0,181, das Antigen 5b eine solche von 0,819. Die Bedeutung wie auch die Grenzen von Kreuzabsorptionen bei solchen Untersuchungen werden diskutiert.

No abstract