Abstract
A higher incidence of malignancy as well as greater susceptibility to infection has been found to be associated with primary immunodeficiencies. An increased incidence of leukemia has been associated with X-linked infantile agammaglobulinemia-an isolated defect of humoral immunities. An increased frequency of a wide variety of malignancies have been found to accompany several different forms of primary immunodeficiency. Secondary immunodeficiencies produced by immunosuppressant therapy to facilitate renal transplantation have also been found to have far too much cancer to be explained by chance assocaition. Many experimental associations between immunity and malignancy have also been encountered, indicating that these two adaptive processes have an essential relationship that must be elucidated.