‘Hidden’ Anti-Rhesus Saline Antibodies

Abstract

A Rhesus antibody of any given specificity, for example, anti-D, occurs in two common forms or states : as a ‘saline antibody’ that will agglutinate red cells suspended in saline, and as an ‘albumin antibody’ that will agglutinate red cells only if they are suspended in a colloid medium or if they are first treated with a proteolytic enzyme. The blood of a sensitized woman may contain either or both, but only the albumin antibody is demonstrable by standard methods in the blood of her newborn baby. Recently, we found saline anti-Rhesus antibodies in the blood of three such babies, following replacement transfusion in two and simple transfusion in one. Albumin antibody but no saline antibody was demonstrable in the blood of each of the three prior to transfusion. None of the donors' bloods contained anti-Rhesus saline antibodies or irregular agglutinins of any other type.