COMPOSITION OF AMYLOID
Amyloidosis is a group of diseases characterized by the deposition of an extracellular protein that has specific properties.
· Individual molecular subunits form β-pleated sheets. Amorphous eosinophilic extracellular deposits of amyloid are seen on the H&E stain. These deposits stain red with the Congo red stain, and apple green birefringence of the amy-loid is seen on the Congo red stain under polarized light.
· The fibrillary protein of amyloid varies with each disease. Also present in amy-loid are serum amyloid P (SAP) and glycosaminoglycans (heparan sulfate).