(1) Acute stressful illness—e.g., myocardial infarction, pneumonia, sepsis; (2) glucocorticoid therapy; (3) lymphoma (esp. Hodgkin's lymphoma); (4) immunodeficiency syndromes—ataxia telangiectasia and Wiskott-Aldrich and DiGeorge syndromes; (5) immunosuppressive therapy—e.g., antilymphocyte globulin, cyclophosphamide; (6) large-field radiation therapy (esp. for lymphoma); (7) intestinal lymphangiectasia (increased lymphocyte loss); (8) chronic illness—e.g., congestive heart failure, uremia, SLE, disseminated malignancies; (9) bone marrow failure/replacement—e.g., aplastic anemia, miliary tuberculosis.