Common variable immunodeficiency.

Common variable immunodeficiency (CVID) is characterized by defective differentiation of B lymphocytes, hypogammaglobulinemia, and infections, although its clinical presentation is much more heterogeneous, with autoimmunity, interstitial lung disease, enteropathy, lymphoproliferation, malignancy, among others. Patients with CVID should undergo extensive immunological evaluations and regular assessment of the multiple organs that may be affected, ideally by multidisciplinary teams specialized in immunodeficiencies. Infections usually improve significantly after the initiation of immunoglobulin replacement therapy and other preventive measures, with non-infectious manifestations now posing the greatest therapeutic challenge. Identifying a genetic cause allows for the reclassification of patients, it has prognostic and therapeutic implications, and enables genetic counseling for family members.