Immunity in Hodgkin's disease: importance of age at exposure.

A relatively common viral agent of low virulence and infectivity might be of etiologic importance in Hodgkin's disease. Age at initial exposure is a major determinant of the outcome of infection (immunity versus clinical disease) and the different epidemiologic patterns for this lymphoma observed internationally. Early exposure, particularly when it occurs in persons from high birth ranks, is associated with a relatively durable immunity. In contrast a delay in initial exposure, also mediated by family factors, results in higher clinical disease-to-immunity ratio. The large male excess in childhood Hodgkin's disease might be due to some sex-linked environmental factor operating early in life and the greater frequency of an asymptomatic carrier state in this sex.