On Isoagglutinin Reactions of Human Blood Other Than Those Defining the Blood Groups

Abstract

Summary A study was undertaken on the occurrence of atypical isoagglutinin reactions of human blood. Such a technic was purposely chosen as would detect sera of even slight activity. In this way rather numerous irregular reactions were found in a material obtained from patients with mental diseases. Most of the reactions observed may be put under the heading of cold agglutination, that is, the sera are active only at low temperature and give very weak agglutination at room temperature (20°). A smaller number of sera (about 3 per cent) contained agglutinins of a type intermediate between cold agglutinins and typical isoagglutinins since their reactions were distinctly noticeable also under the usual conditions of blood grouping. In all of the cases with atypically reacting sera the blood cells showed no abnormal behavior and could readily be grouped. Also the grouping of the sera was not interfered with by the presence of the irregular agglutinins. Hence the irregularities are superimposed upon the much more prominent group properties, and are not in conflict with the scheme of the four blood groups, the usefulness of which cannot be questioned (cf. Thomsen (18)). With regard to the practice of transfusions, it may be stated that in several instances in which the serum of the recipient contained irregular agglutinins for the blood of the donor no untoward symptoms at all were observed. Several sera of groups O, A, and B, described, had agglutinins which were similar with regard to their specificity. In groups A and AB two types of agglutinins were found specific in general for cells of one or the other subgroup of group A; those agglutinating blood AA2 showed in addition a specific action on cells of group O (cf. Schiff (30)). The properties of these sera demonstrate again quite definitely the existence of subgroups in group A, a distinction hardly significant at present for practical purposes. The results with the abnormal agglutinins of human sera give further support to the conclusion that there exists a great number of individual differences of human blood.