immunology allergic disorders
Approach to the Patient With Suspected Immunodeficiency
Introduction
Immunodeficiency typically manifests as recurrent infections. However, recurrent infections are more likely to have causes other than immunodeficiency (eg, inadequate treatment, resistant organisms, other disorders that predispose to infection). Both clinical and laboratory findings are needed for diagnosis. (See also Overview of Immunodeficiency Disorders .) Immunodeficiency can be Primary Immunodeficiencies : Genetically determined, typically manifesting during infancy or childhood Secondary Immunodeficiencies : Acquired, the most common cause of immunodeficiency There are many Causes of Secondary Immunodeficiency , but most immunodeficiencies result from one or more of the following: Systemic disorders (eg, Diabetes Mellitus (DM) , Immunosuppressive treatments (eg, cytotoxic chemotherapy, bone marrow ablation before transplantation, radiation therapy) Prolonged serious illness (particularly in critically ill, older, and/or hospitalized patients) Primary immunodeficiencies are classified by the main component of the immune system that is deficient, absent, or defective: Humoral immunity deficiencies None Cellular immunity deficiencies None Combined humoral and cellular immunity deficiencies None Phagocytic cell defects None Complement deficiencies None 