Sixty-eight children with acute lymphoblastic leukaemia were tested for antibodies to Epstein-Barr (EB) virus and to other viruses. The antibody response to the test viruses in these children was unremarkable, with the exception of EB virus, where the presence of complement-fixing antibodies in children tested during the first month of their illness suggested that a higher proportion had previous experience with this virus than was the case in control children. The implications of this observation with regard to leukaemogenesis are discussed.
