Heterophile IgM, IgA, and IgE antibodies in infectious mononucleosis.

Fifty infectious mononucleosis (IM) and 150 non-infectious mononucleosis (non-IM) sera were tested by a hemadsorption immunocapture test (HIT) for the detection of heterophile antibodies of IgM, IgA, and IgE classes. The specificity of Paul-Bunnell (PB) antibodies was ascertained by a differential absorption test. IgM PB-antibodies were demonstrated in 100% of IM sera, IgA in 92%, and IgE in 88%. PB antibodies were present only in IM sera; but other heterophile antibodies of IgM (68%), IgA (6.7%), and IgE (9.3%) classes were demonstrated in non-IM sera. IgA and IgE heterophile antibodies were thus present, especially in IM sera. HIT was found to be more sensitive than Paul-Bunnell Davidsohn test (PBD test) and suitable for the diagnosis of infectious mononucleosis.