Impairment of Immunological Function in Aplastic Anaemia*

Summary: Since the bone marrow is now believed to be the source of many of the cells participating in immune reactions immunological function was tested in eleven patients with aplastic anaemia. Nine were lymphocytopenic and seven were monocytopenic. Various abnormalities were detected, the most common being failure to show intradermal hypersensitivity in six patients and failure to produce antibody to tetanus toxoid in six. Immunological impairment may be a factor in some of the clinical manifestations of aplastic anaemia.