tonsil, lymph node, or selected B-cell neoplasms
membraneous and cytoplasmic
Regulatory status: IVD, FDA Class I
8385-C010: RTU, 10 capsules; 1 pack
8385-M250: RTU, 250 tests, 1 cartridge; 1 unit
In normal, healthy serum IgM is generally the third most abundant of the immunoglobulin heavy-chain classes. Immunoglobulin (Igs) are produced in mature B-cells and plasma cells, and the amount and type of Ig can vary in different stages of B-cell maturation: Igs in the earlier stages of maturation are present in the cytoplasm, whereas surface expression is more characteristic of mature B-cells in the mantle zone.
The B-cells of the germinal centers show moderate to strong cytoplasmic expression of IgM and the mantle zone B-cells show a moderate to strong membrane staining reaction.
As is typical of most tissues, weak to moderate IgM staining is seen in the extracellular spaces of the mucosa and submucosa of the esophagus.
The islets, pancreatic acinar cells and bile ducts are negative for IgM expression. Background IgM reactivity is seen in vessel lumens and extracellular spaces.