Fatal Infectious Mononucleosis in a Family

Abstract

A 16-year-old boy with a fulminating lymphoproliferative disease, initially believed to be infectious mononucleosis, died within eight days. A herpes-group virus was found on electron microscopy of cells from a lymph-node biopsy. Its identification as Epstein-Barr virus was supported by evidence for transformation of cord-blood leukocytes by spleen extracts, a reaction that was inhibited by neutralizing antibody against the Epstein-Barr virus. Virus DNA sequences were demonstrated in spleen extracts. Immunofluorescent studies disclosed replacement of T lymphocytes by atypical B lymphocytes in blood, in association with loss of mitogen-stimulated leukocyte transformation. These observations are compatible with either an inadequate host response to a common virus or a uniquely aggressive lymphoproliferative disease caused by, or associated with, the Epstein-Barr virus. Since three male cousins died of a strikingly similar disease between the ages of seven and 22 years, a genetically determined defect in host response to the virus is a more likely explanation. (N Engl J Med 290:363–367, 1974)