Age-dependent pattern of intermediate filament protein expression in the human pineal gland.

Intermediate filament distribution was studied in children and adult human pineal glands by using immunocytochemistry and immunoblotting. The demonstration of cytokeratin positive cell clusters in the infant pineal gland may be related to ependymal cells arising from the subcommissural organ. The SCO ependymal cells and the ependymal cells in the pineal parenchyma express the neuro-ectoderm specific individual cytokeratins no. 8 and 18. Cytokeratin positive ependymocytes additionally exhibited vimentin and were serotonin negative as revealed by double immunofluorescence labelling. By contrast, in adult pineal glands cytokeratin positive cells were not clustered. An interesting but unexplained increase of neurofilament 68 KD positive nerve fibres was detectable.