Foreign-body giant cell

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Histopathologic image of aspiration pneumonia in an elderly patient with debilitating neurologic illness. Note foreign-body giant cell reaction. Autopsy case. H & E stain.

A foreign-body giant cell is a collection of fused

foreign body granuloma
.

The human body goes through several steps when exposed to foreign biomaterial including

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]

Formation

Macrophages are phagocytic cells that are produced during an injury or infection.[1] They defend against infectious microorganisms, but also play a role in homeostasis and wound healing.[1] Through the release of Interleukin 4 (IL-4) and Interleukin 13 (IL-13) by TH2, or T helper cells, and mast cells, these macrophages can fuse to form foreign body giant cells.[1][4]

The macrophages are initially attracted to the injury/infection site through a variety of

E-cadherin, CD206, MFR, and CD47, which are different types of receptors.[5] Fusion of these macrophages involves many other proteins, receptors, and molecules as well, but the ones previously mentioned are the most crucial.[5] Finally, macrophages also use filopedia to assist in fusion through sharing cytoplasm between cells.[5]

Function

Foreign body giant cells are involved in the foreign body reaction, phagocytosis, and subsequent degradation of biomaterials which may lead to failure of the implanted material.[4] When produced, the FBGC's place themselves along the surface of the implantation, and will remain there for as long as the foreign material remains in the body.[1]

Macrophages and FBGC's will begin to produce inflammatory molecules in response to the biomaterial.[4] These inflammatory molecules will signal other molecules to respond and begin the process of wound healing.[4]

Microorganisms, particles, and debris that were produced from inserting the biomaterial may be engulfed by macrophages.[1] If the substance is too large for one macrophage, the FBGC's can attempt to engulf the foreign material for degradation.[1]

FBGC's will also begin to produce

reactive oxygen intermediates, enzymes for degradation, and acid between their cell membranes and the surface of the biomaterial.[1][4] The composition of the biomaterial will determine how compatible and durable it is in the body.[4] If too much damage occurs due to the chemicals that are produced, the biomaterial may fail and have to be replaced.[4]

  • Foreign-body giant cell reaction to a suture. H&E stain.
    Foreign-body giant cell reaction to a suture. H&E stain.
  • Micrograph showing a foreign body engulfed by a giant cell. H&E stain.
    Micrograph showing a foreign body engulfed by a giant cell. H&E stain.
  • Foreign body giant cell reaction to silicone leakage from breast implant. H&E stain.
    Foreign body giant cell reaction to silicone leakage from breast implant. H&E stain.

References

  1. ^
    PMID 28793529
    .
  2. PMID 24069561
    .
  3. PMID 19057205
    .
  4. ^
    PMID 18162407
    .
  5. ^
    Elsevier Science Direct
    .

External links
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