Serological Findings in Infectious Mononucleosis

To the Editor:  —It is entirely possible that lower titers than indicated in my answer may be found in infectious mononucleosis. However, there is room for a difference of opinion if one makes the assumption that the positive diagnosis of infectious mononucleosis could and should be made on the basis of serologic reactions in the range given in the above communication.The question which I had attempted to answer was as follows: "The definitive diagnosis of infectious mononucleosis rests upon what serological and clinical evidence?" In my opinion, the diagnosis of infectious mononucleosis should not be made on the basis of merely the serological findings, most particularly when these serological findings are associated with titers in the very low range. Illustrative of the confusion that may arise if complete reliance is placed on the serological findings is Case 12 in the article entitled "Ox Cell Hemolysin in Infectious Mononucleosis and