Primary antibody deficiencies (PAD) constitute the majority of all primary immunodeficiency diseases (PID) also termed inborn errors of immunity (IEI). This category (PAD) represents around 52% of all IEI and the proportion overall is still greater given that antibody deficiency is a component of other groups including combined immunodeficiencies (CID and 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 or gastrointestinal immunoglobulin losses, infections (HIV, malaria) and globally malnutrition (3).

The manifestations of PADs are protean and encompass a range of infectious and non-infectious complications, including autoimmune, lymphoproliferative, granulomatous and allergy manifestations due to an immunedysregulation, and increased risk of malignancy in some forms of PADs (4,5).