Does immunohistochemistry allow easy detection of lymphatics in the optic nerve sheath?

We evaluated the validity of anti-D2-40 and anti-LYVE-1 (antibodies against lymphatic endothelium) for IHC diagnosis and semiquantification of lymphatic vessels in the dura mater of the intraorbital portion of the human optic nerve (ON). Fourteen specimens were analyzed using light microscopy within 12 hr postmortem. We found in all specimens that both D2-40 and LYVE-1 stained lymphatic vessels as well as venules and arterioles. Our findings show lymphatic vessels in the meninges of the intraorbital portion of the human ON. Anti-D2-40 and anti-LYVE-1 antibodies, however, are not found to be exclusively specific to the endothelial layer of lymphatics because they also stain the endothelial layer of venules and arterioles. For the unequivocal identification of lymphatics, additional morphological criteria are necessary. Nevertheless, D2-40 and LYVE-1 staining allows rapid identification of endothelial layers.