A Human Serum Containing Four Distinct Isoagglutinins

Abstract

The serum to be described was studied because the patient from whom it was derived had had hemolytic reactions following transfusions of apparently compatible blood. In this report we shall present the serologic findings; the clinical data will be described elsewhere. 1

The patient belonged to group 0, type N. The patient's serum agglutinated every one of 28 consecutive group 0 bloods. That we were not dealing with an autoagglutinin was proved by the absence of agglutination in mixtures of the patient's serum with her own cells. Evidently the serum contained isoagglutinins in addition to anti-A and anti-B.

Since the patient was Rh negative, 2 , 3 it seemed possible that anti-Rh isoagglutinins might be present in her serum. Accordingly the serum was absorbed with pooled, washed cells A₁MNRh- and BMNRh-. The absorbed serum was found to give reactions coinciding with those of standard Rh antisera, proving that the anti-Rh isoagglutinin was present. Since tests on Rh negative bloods with the unabsorbed serum showed that most of the bloods were agglutinated, it was evident that another irregular isoagglutinin was present. Difficulty was encountered in separating the unknown isoagglutinin from the anti-Rh isoagglutinin by absorption experiments. A separation between them was readily effected, however, when it was found that the anti-Rh isoagglutinin acted strongly at body temperature, and not at all at refrigerator temperature, while the unidentified isoagglutinin acted only in the cold.

In order to ascertain the nature of the fourth isoagglutinin, it was necessary to test a larger series of bloods. On account of the presence in the patient's serum of anti-A and anti-B isoagglutinins, bloods of groups A, B, and AB could not be tested directly. It was found that by the simple addition to the patient's serum of a solution of the group substances A and B (Table I), the action of the interfering α and β isoagglutinins could be completely neutralized without affecting the activity of the anti-Rh isoagglutinin or the other irregular isoagglutinin.