Hypogammaglobulinemia

Synonyms

Agammaglobulinemia, humoral immunodeficiency.

Definition

Hypogammaglobulinemia (usually less than 200–250 mg/dl of IgG) results from lack of production; excessive loss of immunoglobulins; or both. It is conventionally divided into acquired and primary types. In adults the most common of the primary types is common variable immunodeficiency, the precise cause of which has not been determined, but the basis appears to be a defective gene in the class III region of the MHC. In this disorder, there is usually a deficiency in both IgG and IgA. Other primary types include severe combined immunodeficiency, adenosine deaminase deficiency, and the X-linked immunodeficiency diseases. (See definitions for these). Acquired hypogammaglobulinemia is more common than primary deficiency disorders, and malnutrition is probably the most common worldwide cause of acquired disease. Other causes for acquired hypogammaglobulinemia include neoplasms such as multiple myeloma, chronic lymphocytic...