What is the role of serum immunoglobulin measurement in the workup of hypogammaglobulinemia?

Updated: Dec 26, 2018
  • Author: Elizabeth A Secord, MD; Chief Editor: Michael A Kaliner, MD  more...
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The evaluation of patients with suspected hypogammaglobulinemia should include quantitative measurement of serum immunoglobulins. If these levels are normal and a humoral immunodeficiency still is suggested, antibody response to specific antigens (polysaccharide and protein antigens) should be determined. [13, 8, 7, 5] The impaired antibody responses to various pathogens in hypogammaglobulinemic states may make serological diagnosis of certain infections (eg, HIV, Epstein-Barr virus [EBV]) difficult. In these patients, nucleic acid detection methods (ie, PCR or reverse PCR) may be the best diagnostic tests for certain viral infections.

Perform serum protein electrophoresis for presumptive diagnosis of hypogammaglobulinemia or monoclonal protein. Quantitative methods using immunodiffusion or nephelometry are used for the precise measurements of each isotype of Ig. Enzyme-linked immunosorbent assay is used for IgE quantitation.

Values must be compared with age-standardized reference ranges.

Common variable immunodeficiency (CVID) is defined by IgG levels less than 2 standard deviations below the mean, with equally low levels of IgA, IgM, or both. [13, 10]

Serum IgA is less than 5 mg/dL, with normal IgG and IgM levels, in selective IgA deficiency. levels of IgG2 and IgG4 also may be decreased, especially in patients with sinopulmonary infections.

In hyper-IgM syndromes, IgM may be markedly increased to levels frequently higher than 1000 mg/dL. However, the level of IgM often gradually increases with time and may be normal in children. levels of IgG, IgA, IgE, and the lymphocytes bearing these antibodies are decreased. IgM response to antigens is possible, but IgG and IgA responses are absent or diminished.

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