Replacement therapy in adults, and children and adolescents (0-18 years) in: • Primary immunodeficiency syndromes (PID) with impaired antibody production • Secondary immunodeficiencies (SID) in patients who suffer from severe or recurrent infections, ineffective antimicrobial treatment and either proven specific antibody failure (PSAF)* or serum IgG level of <4g/l. *PSAF=failure to mount at least a 2-fold rise in IgG antibody titre to pneumococcal polysaccharide and polypeptide antigen vaccines Immunomodulation in adults, and children and adolescents (0-18 years) in: • Primary immune thrombocytopenia (ITP), in patients at high risk of bleeding or prior to surgery to correct the platelet count • Guillain Barré syndrome • Kawasaki disease (in conjunction with acetylsalicylic acid; see 4.2) • Chronic inflammatory demyelinating polyradiculoneuropathy (CIDP) • Multifocal motor neuropathy (MMN) Immunomodulation in adults with: • Active dermatomyositis treated with immunosuppressive drugs including corticosteroids, or with intolerance or contra-indications to those drugs