Fatal disseminated BCG infection. An investigation of the immunodeficiency.

A 2-year-old boy had a fatal disseminated BCG infection. Immunologic assessment showed a normal humoral response and normal numbers of E rosettes, normal thymus weight and histological features, but an abnormal response of lymphocytes in vitro and negative skin tests. Histological examination showed the presence of Gram-negative acid-fast bacilli within the macrophages. The possible mechanisms of immunodeficiency in this patient are discussed.