Erythrocytes of group 0 cde/cde successively treated with bromelin and beta-glucuronidase (DFE) react not only with antibodies (anti-DFE) contained in the IgM-fraction of each human serum but also with Rh-specific antibodies of the IgG-fraction of anti-Rh-sera. This indicates, that the enzyme treatment makes accessible two different possibly crossreacting structures. Since anti-DFE is contained in the IgM-fraction of all human-sera, the antigenic determinant reacting with anti-DFE is considered a polyagglutinogen not identical with the well known polyagglutination-phenomena (T, Tn and Cad) as it is shown by comparative investigations with anti-T and anti-Tn as well as anti-Cad active seed extracts.