Concurrent infectious mononucleosis and acute leukemia: Case reports. Review of the literature and serologic studies with the herpes-type virus (EB virus)

Abstract

The development of infectious mononucleosis (IM) in the course of acute lymphocytic leukemia (ALL) appears to have a favorable effect on the latter disease, as determined from published cases, unpublished data tabulated in this report and two closely followed cases presented in detail. In addition, after convalescence these patients appear to have high titers to EB virus (EBV), the agent considered by many to cause IM. When serial serum specimens were available, a secondary rise in antibody titer well after recovery from IM was documented. This rise possibly is unique to the concurrence of these two diseases, since titers in patients without leukemia fall after recovery from IM and remain relatively constant, and we have shown here that in ALL titers do not rise routinely. Serum samples from patients with long survival after ALL (three and a half to fifteen years) without a history of concurrent IM were also assayed and found to have a geometric mean anti-EBV titer higher than various control groups. However, there was considerable overlap in individual titers, and expanded study of this phenomenon is required to assess its significance. The features of IM in patients with ALL are noted. Seroconversion to EBV is indicated in one case during the incubation period and before symptoms of IM, in contrast to earlier reports; this is thought to be related to the sensitivity of the assay method. If further study supports an association of IM, clinical and subclinical EBV infection, titer of EBV antibodies and favorable course of leukemia, the mechanism remains to be elucidated. Precedents from laboratory investigation and clinical observation are noted, and some hypotheses are briefly discussed.