immunology allergic disorders
Overview of Immunodeficiency Disorders
Secondary Immunodeficiencies
Causes (see table Causes of Secondary Immunodeficiency ) include Systemic disorders (eg, Diabetes Mellitus (DM) , 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. Prolonged serious illness may impair immune responses; impairment is often reversible if the underlying illness resolves. Rarely, prolonged exposure to toxic substances (eg, certain pesticides, benzene) can be immunosuppressive. Immunodeficiency can result from loss of serum proteins (particularly IgG andalbumin) through the following: The kidneys in nephrotic syndrome The skin in severe burns or dermatitis The gastrointestinal (GI) tract in enteropathy Enteropathy may also lead to lymphocyte loss, resulting in lymphopenia. Treatment focuses on the underlying disorder; for example, a diet high in medium-chain triglycerides may decrease loss of immunoglobulins (Igs) and lymphocytes from the gastrointestinal tract and be remarkably beneficial. If a specific secondary immunodeficiency disorder is suspected clinically, testing should focus on that disorder (eg, diabetes, HIV infection, cystic fibrosis, primary ciliary dyskinesia). 