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Infectious mononucleosis and acute leukemia.

To the Editor.— Interest in the possible relation of infectious mononucleosis to leukemia and lymphoma has quickened recently with the detection of the Epstein-Barr (EB) virus in patients with mononucleosis and Burkitt's lymphoma. 1 Many workers have felt that if mononucleosis and lymphoreticular neoplasms are induced by the same agent, one disorder might protect against the other. Therefore, when a series of children was observed with mononucleosis and acute leukemia, Freedman et al ( 214 :1677, 1970) suggested that the two diseases were etiologically unrelated. Support for this interpretation comes from data of the National Cooperative Leukemia Survey, in which 12 medical centers participated. 2 The Survey was conducted by interviewing the parents of 484 leukemic children under 16 years of age and the parents of neighborhood controls matched by age, birth order, family size, and race. The inquiry included a question on the occurrence of infectious mononucleosis among the leukemic