Infectious mononucleosis.

Infectious mononucleosis is a unique disease in its hematologic aspects; it is different from the frequently occurring acute microbial diseases in that it affects primarily the reticuloendothelial system; and it is interesting serologically because of the heterophil antibody reaction, as well as the multiplicity of antibodies which may be produced. The diagnosis should be suspected clinically before hematology is reported - by remembering the prototypes. In fact, a patient between 16 and 25 years old who complains of sore throat and fever is more likely to have infectious mononucleosis than another disease; and if - in addition - he is jaundiced, a diagnosis of infectious mononucleosis is almost certain. Finally, a negative result of treatment with corticosteroid has the diagnostic significance mentioned above. Positive effect of treatment has no diagnostic significance.