Glial fibrillary acidic protein in chondrocytes of elastic cartilage in the human epiglottis: an immunohistochemical study with polyvalent and monoclonal antibodies.

Glial fibrillary acidic protein (GFAP), an intermediate filament, was first discovered in the cytoplasm of reactive astroglia and to this date is regarded as a rather characteristic component of both non-neoplastic and neoplastic astrocytes. It has, however, been found in other glial elements also, as well as in a few types of tissues outside the central nervous system. Chondrocytes in hyaline and fibrocartilage do not express GFAP, but in the elastic cartilage of the human epiglottis we found GFAP to be regularly present when tested with either polyclonal or monoclonal antibodies. While most types of cartilage in humans are believed to be of mesenchymal origin, embryologic relationship between epiglottal cartilage and the neural crest may play a role in the curious phenomenon of the regular presence of GFAP in the chondrocytes of the epiglottis.