Letters to Editor

Abstract

IN 1945 a cell sample was discovered reacting with only a proportion of anti-D sera. This suggested a new allele of D which was called D^u1. 209 Rh antisera stored at – 20° C. for periods up to several years have been tested with D^u cells of types CD^ue and cD^uE, selecting the appropriate cell to avoid the effect of anti-C and anti-E agglutination in sera containing more than one antibody. 102 of these sera contained anti-Rh agglutinins, and 37 of these (36 per cent) agglutinated D^u cells, some weakly, some very strongly. These sera all contained anti-D + D^u agglutinins; anti-D^u by itself has not been detected. 71 of these agglutinating sera Were free from anti-C and anti-E agglutinins, and 27 of these (38 per cent) agglutinated D^u cells. These 27 comprised 13 percent of all the sera tested. The remaining 107 sera contained incomplete antibodies, many of which were weak; and 36 of them (34 per cent) gave positive Coombs tests with D^u cells. Eight of these gave positive albumin tests also, and five sera gave positive albumin tests only. In addition, strong incomplete Rh antibodies from ten cases of incompatible transfusion all gave positive Coombs tests with D^u cells, as did ten agglutinating sera which gave negative agglutination with D^u cells.