Primary Immunodeficiency Diseases - Immunoglobulin Disorders

Primary immunodeficiency diseases (PIDDs) result from inherited genetic defects and represent a highly heterogeneous group of disorders.  PIDDs typically present with severe, repetitive infections caused by organisms of low virulence   and are usually detected during childhood; however, the most common clinically significant PIDD, common variable immune deficiency (CVID), has a peak onset in the second and third decades of life.  PIDDs are roughly categorized as antibody deficiencies (B cell, T cell, or combined), phagocytic defects (eg, chronic granulomatous disease [CGD]), and complement disorders.  Antibody deficiencies are the most common type of PIDD  and can be broadly characterized by the presence or absence of B cells. The resulting disorders range from severe forms (CVID, X-linked agammaglobulinemia) to milder forms, which are covered here.

A careful, stepwise laboratory evaluation is recommended to diagnose an underlying PIDD.  After eliminating conditions that may increase susceptibility to infection (eg, adenoid hypertrophy, cystic fibrosis, immunosuppression), an initial workup may include CBC, quantitative serum immunoglobulins, IgG vaccine titers, and complement testing.  These tests are often insufficient to make a definitive diagnosis, so advanced tests (eg, flow cytometric-based assays to test immune cell function, cytokine production, cellular signaling pathways, and protein expression) are often necessary. Genetic testing may also be warranted. 

Tabs Content
Content Review: 
March 2019

Last Update: April 2019