A foreign-body giant cell is a collection of fused macrophages (giant cell) which are generated in response to the presence of a large foreign body. This is particularly evident with catheters, parasites, or biomaterials that are inserted into the body for replacement or regeneration of diseased or damaged tissues.[1][2] Foreign body giant cells are also produced to digest foreign material that is too large for phagocytosis.[3] The inflammatory process that creates these cells often leads to a foreign body granuloma.
The human body goes through several steps when exposed to foreign biomaterial including acute and chronic inflammation, and formation of new tissue and a fibrous capsule along the surface of the implantation.[1] Foreign body reactions, which are a type of chronic inflammation, are characterized by the presence of macrophages, monocytes, and foreign-body giant cells (FBGCs).[1][4] The response of the foreign body reaction determines how compatible the implanted material will be in the body, and the members of the foreign body reaction, including the FBGC's, remain along the surface of the biomaterial for its lifetime in the body.[1]
Foreign body giant cells are formed through signaling from IL-4 and IL-13, and may fuse to produce a multinucleated cell with up to 200 nuclei within its cytoplasm.[5]