IgDs
Immunoglobulin D (IgD) is one of the five major classes of immunoglobulins found in jawed vertebrates. In humans, IgD is primarily expressed on the surface of naive B lymphocytes as part of the B cell receptor (BCR) together with membrane-bound IgM; circulating IgD exists at relatively low levels in serum, and its precise functions are less well defined.
IgD is encoded by the delta heavy-chain (IGHD) gene within the immunoglobulin heavy-chain locus. On B cells,
Naive B cells typically co-express IgM and IgD on their surface, and signaling through the IgD-containing BCR
Clinical and research notes: IgD deficiency is rare and not widely documented. Some conditions, such as hyper-IgD