Immunoreactivity of exfoliation material for the cell adhesion-related HNK-1 carbohydrate epitope.

Objective: To study the presence of the HNK-1 epitope in exfoliation material.
Methods: Twenty-six formalin-fixed, paraffin-embedded human eyes with exfoliation syndrome and 30 control eyes were studied immunohistochemically with monoclonal antibodies HNK-1 and VC1.1 to the HNK-1 epitope.
Results: Exfoliation material reacted consistently with antibodies to the HNK-1 epitope. The zonular lamella of the lens, inner surface of the nonpigmented ciliary epithelium, and inner connective tissue layer of the ciliary body were also labeled, but the lens capsule, epithelium, and zonules were not immunoreactive. Several blood vessels of the iris showed granular immunoreaction beneath the endothelium in all exfoliation eyes and in 11 (37%) of 30 control eyes, representing older age groups.
Conclusions: The zonular lamella, nonpigmented ciliary epithelium, or the inner connective tissue layer may be responsible for the HNK-1 epitope in exfoliation material. Since this epitope is shared by many cell-adhesion molecules, its presence in exfoliation material might be of pathogenetic significance to the formation of the deposits.