[Primary immunodeficiency]

Primary (inborn) immunodeficiency is caused by gene defects that impact both the innate and the adaptive immune system. Individuals with an immunedeficiency primarily come to medical attention with recurrent infections. Most diagnoses are first made in childhood and include cellular immunodeficiency, defects of phagocyte function and other primary immunodeficiencies. Antibody deficiencies, particularly common variable immunodeficiency (CVID) and complement defects may, however, not become manifested until adulthood. A pathological susceptibility to infection in adults is defined as more than three infections per year that require treatment with antibiotics and last longer than 4 weeks each. Clinical clues for immunodeficiency are pathological susceptibility to infections and immune dysregulation. The former is characterized by frequent and severe infections with often unusual pathogens, localization, course and/or intensity. Immune dysregulation comprises granulomas, autoimmune diseases, recurrent fever/chronic inflammation, tendency to eczema, lymphoproliferation and chronic enteritis. There are evidence-based guidelines and consensus documents for the diagnosis and treatment of primary immunodeficiencies. Therapeutic approaches depend on the nature of the immune defect and range from immunoglobulin substitution for antibody deficiencies to bone marrow transplantation for severe cellular immune defects.