“…With ME-induced agglutination, the second stage of the isoantibody-antigen reaction, agglutination of the red cell mass may perhaps be a nonspecific process influenced by the suspending medium or by alteration of the red cell surface. 9 The latter suggestion is supported by the observation of Davis, Green, and Tymms (16), in studies by electron microscopy, that changes on the red cell surface may be brought about by sensitization with anti-D. In addition, it is generally agreed that enzymes, by altering the red cell surface, enhance agglutination of sensitized cells.…”