Common Variable Immunodeficiency (CVID)

Common Variable Immunodeficiency (CVID) refers to a heterogeneous group of primary immune deficiency disorders (PIDD) presenting with recurrent sinopulmonary infections, hypogammagloblunemia, inadequate vaccination responses, and in a subset, co-existent autoimmune and inflammatory disease. The definition and diagnosis of CVID has evolved since its recognition in 1971 from one of exclusion to include the laboratory and clinical manifestations of hypogammaglobulinemia. In 1991, the European Society for Immunodeficiency and the Pan American Group for Immunodeficiency (ESID/PAGID) established formal diagnostic criteria as probable indicators of CVID: a decrease in serum immunoglobulin G (IgG) of at least two standard deviations below the mean for age, a decrease in one or both of the isotypes IgM and IgA, age of onset greater than 2 years, absent hemagglutinins or poor response to vaccines, and a lack of other causes for hypogammaglobulinemia. These diagnostic criteria remained in effect until 2014 when the ESID registry released slightly refined criteria that contains the following additions and alterations: minimum age of diagnosis of 4 years, at least one symptom related to the PIDD or evidence of family history of the disorder, and no evidence of profound T cell deficiency. As there is no universally accepted definition or diagnostic criteria, efforts are continuously being made to more clearly define exactly what constitutes CVID both clinically and biologically with the recognition that it likely represents several different genetic defects with phenotypic variation.