Immunology 131 (4): 451 - 458, 2010. doi: 10.1111 / j.1365 - 2567.2010.03360.x Secondary Immunodeficiencies Causes (see table Some Disorders That Cause Secondary Immunodeficiency) include Systemic disorders (eg, diabetes, undernutrition, HIV infection) Immunosuppressive treatments (eg, cytotoxic chemotherapy, bone marrow ablation before transplantation, radiation therapy) Prolonged serious illness Secondary immunodeficiency also occurs among critically ill, older, or hospitalized patients.