COMMON VARIABLE IMMUNE DEFICIENCY (CVID)
Most patients with primary antibody deficiency are collected under the heading “common variable immune deficiency,” which is condition characterized by low serum IgG and IgA and a variable decrease in IgM and the impaired production of specific antibodies following natural microbial exposure or immunization. The estimated prevalence of CVID is between 1 in 10,000 and 1 in 50,000. Clinically, CVID is dominated by the effects of antibody deficiency. About 20 percent of patients with CVID develop autoimmune disorders (arthritis, cytopenias, endocrinopathies). Some patients with CVID develop noncaseating sarcoidlike granulomata infiltrating various organs (lungs, liver, spleen, skin). The mechanisms underlying autoimmunity and granulomatous disease in CVID are unknown.