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Unit Code 300157:
Immunoglobulin A (IgA), Serum

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Useful For

Detecting and monitoring of monoclonal gammopathies and

immune deficiencies

Clinical Information

The gamma-globulin band as seen in conventional serum protein

electrophoresis consists of five immunoglobulins. In normal serum,

about 15% is IgA.

 

Monoclonal elevation of IgA characterize multiple myeloma.

 

Monoclonal gammopathies of all types may lead to a spike in the

gamma-globulin zone seen on serum protein electrophoresis.

 

Decreased immunoglobulin levels are found in patients with congenital

deficiencies.

 

Reference Values

0-4 months:  5-64 mg/dL

5-8 months:  10-87 mg/dL

9-14 months:  17-94 mg/dL

15-23 months:  22-178 mg/dL

2-3 years:  24-192 mg/dL

4-6 years:  26-232 mg/dL

7-9 years:  33-258 mg/dL

10-12 years:  45-285 mg/dL

13-15 years:  47-317 mg/dL

16-17 years:  55-377 mg/dL

> or = 18 years:  50-400 mg/dL

Interpretation

Increased serum immunoglobulin concentrations occur due to

polyclonal or oligoclonal immunoglobulin proliferation in hepatic

disease (hepatitis, liver cirrhosis), connective tissue diseases,

acute and chronic infections, as well as in the cord blood of

neonates with intra-uterine and perinatal infections.

 

Elevation of IgA may occur in monoclonal gammopathies such as

multiple myeloma, primary systemic amyloidosis, monoclonal gammo-

pathy of undetermined significance, and related disorders.

 

Decreased levels are found in patients with primary or secondary

immune deficiencies.

Cautions

Electrophoresis is usually required to interpret an elevated

immunoglobulin class as polyclonal vs. monoclonal.

Immunofixation is usually required to characterize

a monoclonal protein.

 

If there is a discrete M-peak, the monoclonal

protein can be monitored with quantitative immunoglobulins.

If immunoglobulin quantitation is used to monitor the size of a

monoclonal protein which is contained in a background of polyclonal

immunoglobulins, however, changes in the immunoglobulin quantitation

may reflect changes in the background immunoglobulins, and serum

protein electrophoresis should therefore be used to monitor the

monoclonal protein.

Clinical Reference

Webster ADB: Laboratory Investigation of primary deficiency

of the lymphoid system. In Clinics in Immunology and Allergy.

Vol. 5. Third edition. Philadelphia, PA, Saunders, 1985, pp 447-468

 

Pinching AJ: Laboratory investigation of secondary immunodeficiency.

In Clinics in Immunology and Allergy. Vol. 5. Third edition. Philadelphia,

PA, Saunders, 1985, pp 469-490

 

Dispenzieri A, Gertz MA, Kyle RA: Distribution of diseases associated

with moderate polyclonal gammopathy in patients seen at Mayo

Clinic during 1991. Blood 90:353, 1997

 

Kyle RA, Greipp PR: The laboratory investigation of monoclonal gamm-

opathies. Mayo Clin Proc 53:719-739, 1978

 

Ballow M, O'Neil KM: Approach to the patient with recurrent

infections.  In Allergy:  Principles and Practice. Vol. 2. Fourth

edition. Edited by E Middleton Jr, CE Reed, EF Ellis, et al. St.

Louis, MO, Mosby-Year Book, Inc., 1993, pp 1027-1058

 

Kyle RA: Detection of quantitation of monoclonal proteins. Clin

Immunol Newsletter 10:84-86, June 1990

Key