Primary Immunodeficiency

Key points

• Primary immunodeficiency disorders may be classified according to which component of the immune system they affect
• B-cell disorders (e.g. common variable immunodeficiency, selective IgA deficiency): typically cause recurrent bacterial infections, particularly of the respiratory tract
• T-cell disorders (e.g. DiGeorge syndrome): predispose to recurrent viral, fungal and opportunistic infections
• Combined B- and T-cell disorders (e.g. severe combined immunodeficiency, Wiskott-Aldrich syndrome): cause severe, recurrent infections from infancy
• Phagocytic disorders (e.g. chronic granulomatous disease): cause recurrent pneumonias and abscesses, particularly due to catalase-positive organisms
• Complement disorders (e.g. C1-INH deficiency): predispose to recurrent angioedema and, in some cases, autoimmune disease and recurrent infections