Abstract

The immune status of 33 mothers, 17 fathers, and 14 sibs of children with acute lymphoblastic leukaemia was studied with the following tests: peripheral blood lymphocyte counts, lymphocyte transformation with phytohaemagglutinin, serum immunoglobulin levels, isohaemagglutinin titres, and levels of antibody to herpes simplex and Epstein-Barr viruses. No significant abnormality was shown by these tests, with the exception of a lymphocytosis detected in parents at an early stage of their child's disease. The significance of these findings is discussed in the light of the concept that viral infection relates to the aetiology of childhood leukaemia. It is concluded that there is no defect of immunity in these families.