Immunoglobulin D (IgD)

IgD is mainly found on the surface of B cells and may help regulate B-cell function. IgD likely serves as an early B-cell antigen receptor; however, the function of the circulating IgD is largely unknown. IgD functions to activate some lymphocytes.

Normal value: ≤15.3 mg/dL.

Use

Diagnosis of rare IgD myelomas (greatly increased)

Interpretation

Increased In

Monoclonal

IgD multiple myeloma

MGUS

Polyclonal

Chronic infection (moderately)

Autoimmune disease

Acute viral hepatitis

COPD

After allogeneic bone marrow transplantation

Decreased In

Hereditary deficiencies

Acquired immunodeficiency

Non-IgD myeloma

Infancy, early childhood

Limitations

An elevated IgD need to be identified as monoclonal or polyclonal by immunofixation method.