Use

Measurement of the concentrations of IgG subclass proteins in serum is useful in evaluating patients with clinical signs and symptoms of humoral immunodeficiency or combined immunodeficiency (cellular and humoral). Diminished concentrations of one or more IgG subclass proteins may occur in conditions like hypogammaglobulinemia, common variable immunodeficiency, or may be selective. Most patients with IgG subclass 2 deficiency present with recurrent infections such as sinusitis and pulmonary infections, and children may exhibit deficient antibody responses to antigens. Isolated deficiencies of IgG subclass 3 or 4 occur rarely, and their clinical significance is not well understood.