Primary Immunodeficiencies (PI) are a group of disorders that affect the function of one or more parts of the immune system. These disorders can affect people of any age, with an estimated prevalence of 1:1200 individuals. The most common consequence of immunodeficiency is recurrent, severe, persistent or unusual infections. An abnormal immune system also increases the risk of autoimmune disorders, inflammatory diseases, allergic diseases and cancer. The most common forms of primary immunodeficiency are due to defects in production of antibodies, such as common variable immunodeficiency (CVID), selective IgA deficiency, and specific antibody deficiency. The adult PI center focuses on early recognition, essential diagnostic workup, selection of appropriate long-term therapy, and a multidisciplinary approach to management.