Vasssilios Lougaris, Giacomo Tampella, Manuela Baronio, Massimiliano Vitali and Alessandro Plebani
B cells are generated in the bone marrow and then enter the periphery, where the maturation process takes place leading to the formation of an effective humoral immune response. Defects in this highly regulated process in the periphery have been considered to be responsible for the pathogenesis of Common Variable Immunodeficiency (CVID) for more than 6 decades. CVID is traditionally characterized by low immunoglobulin serum levels and defective antibody response in the presence of normal peripheral B cell numbers. The clinical spectrum of CVID is highly variable, including recurrent infections, autoimmune complications and increased susceptibility to cancer and lymphomas. However, only in the last decade, the genetic defects underlying this maturational B cell defect have been partially elucidated in a small percentage of affected patients. This review will focus on the current state of art regarding the known genetic alterations associated with the pathogenesis of CVID.