CHEMICAL, CLINICAL, AND IMMUNOLOGICAL STUDIES ON THE PRODUCTS OF HUMAN PLASMA FRACTIONATION XXIX. SERUM ALBUMIN AS A DILUENT FOR

During the last two years methods for the separation and concentration of the anti-Rh iso-agglutinins have been developed as a part of the study of the fractionation of human plasma (1). The solubility characteristics on which the separa-tion has been based resemble those of the anti-A and anti-B isoagglutinins, and have been summar-ized in a previous communication (2). The final products have been prepared as protein powders, stable and readily soluble, which may be packaged in convenient quantities and reconstituted to yield potent reagents useful for Rh typing or for A or B grouping, respectively. In contrast to the anti-A and anti-B isoagglu-tinins, which may be obtained readily from grouped plasma pools from normal donors (3), the avail-able supply of anti-Rh material is limited. The incidence of anti-Rh agglutinins in the general population is very low, and bleedings suitable as a source of original plasma for processing "'must be obtained from sensitized Rh negative donors, specially selected (2). Moreover, the phenome-non, termed "blocking, " 8 whereby the antibodies in certain anti-Rh serums fail to agglutinate homologous Rh positive cells in sodium chloride solutions, but appear to combine with them and to inhibit the action of Rh agglutinins (4, 7, 8), has made these serums and the anti-Rh globuli