Infectious mononucleosis prior to acute leukemia: A possible role for the epstein‐barr virus

Three cases of ALL preceded by IM are reported. One patient developed leukemia associated with an apparent recurrence of IM 17 months later. The other two patients, who were diagnosed as having IM one month prior to the appearance of their leukemia, had a poor response to chemotherapy and died after a brief illness. All patients had antibody to the EBV viral capsid antigen, and two had antibody to the EBV‐associated early antigen. Although IM and ALL are suspected of being caused by a virus, epidemiologic and laboratory studies indicate that the etiology of these diseases is distinct. Since IM has been well documented as a preceding event in cases of ALL as well as other lymphocytic neoplasms, it is possible that EBV may be able to activate or “switch‐on” an oncogenic process in a manner similar to that described for murine leukemia.