Medical Algorithm: Diagnosis and Management of Antibody Immunodeficiencies.

Primary antibodydeficiencies (PAD) constitute the majority of all primary immunodeficiency diseases (PID) also termed in born errors of immunity (IEI). This category (PAD) representsaround 52% of all IEI and the proportion overall is still greater given that antibody deficiency is a component of other groups including combined and severe combined immunodeficiencies (SCID), autoinflammatory disorders, diseases of immune dysregulation and other well defined PIDs(1,2). Secondary antibody deficiencies (SAD) represent a larger and expanding number of individuals resulting from the use of a wide range of immunosuppressive therapies, in particular those targeting B cells, and may also result from renal orgastrointestinal immunoglobulin losses, infections, for example HIVormalaria,malnutritionorothers(3).