Cold-haemagglutinin disease with an autoantibody exhibiting different specificities at different temperatures

A case of chronic cold-haemagglutinin disease is reported in which an agglutinin apparently carrying two specificities was present. At first, specificity was anti-not-I and anti-I respectively: in the course of time anti-I was replaced by anti-A-1. Both anti-I and anti-A-1 could be demonstrated at room temperature only while specificity was anti-not-I at 4 degrees C. The antibody displayed haemolytic activity at room temperature and gave stronger reactions when treated biphasically. The same pattern of specificity was apparent in haemolysis tests, i.e. anti-not-I in the biphasical reaction 4 degrees C goes to 37 degrees C and first anti-I and later anti-A-1 at room temperature and at 22 degrees C goes to 37 degrees C. Anti-A-1 was not neutralized by A bloodgroup substance of animal origin nor by secretor saliva.