Characterization of human heterophile antibodies apparently induced by alloimmunization

Human heterophile antibodies reactive with various tissues of different species may be detected by indirect immunofluorescence. Results of screening sera obtained after rhesus immunization and before and after blood transfusion and renal transplantation suggest that such antibodies can appear following alloimmunization of group A and O individuals. Eleven positive sera selected for detailed study were found to have anti-B isohaemagglutinins together with rat erythrocyte agglutinins. Absorption studies suggested that there may be some relationship between the group B antigen and the rat antigen concerned but the precise explanation for alloimmunization remains to be determined.