Patients may experience severe hypersensitivity reactions or anaphylaxis in the setting of detectable IgA levels following infusion of GAMMAGARD S/D. The occurrence of severe hypersensitivity reactions or anaphylaxis under such conditions should prompt consideration of an alternative therapy. GAMMAGARD S/D is contraindicated in patients with selective IgA deficiency where the IgA deficiency is the only abnormality of concern (see INDICATIONS AND USAGE and WARNINGS sections).