An IgD immunoglobulin complex in human. IgD is composed of two identical immunoglobulin heavy chains of the IgD isotype and two identical immunoglobulin light chains (kappa or lambda), held together by disulfide bonds. An IgD immunoglobulin complex may be embedded in the plasma membrane or present in the extracellular space, in mucosal areas or other tissues, or circulating in the blood or lymph. [ http://www.ncbi.nlm.nih.gov/pubmed/11282392 https://www.worldcat.org/search?q=bn%3A0781765196 ]