D2-40 expression demonstrates lymphatic vessel characteristics in the dural portion of the optic nerve sheath

Purpose: To investigate the presence or absence of lymphatic vessels in the human optic nerve by means of immunohistochemistry. Methods: Use of selective molecular markers to differentiate lymphatics from blood vessels in optic nerve specimens obtained after enucleation or exenteration procedures. Specifically, the lymphatic-specific monoclonal antibody 132-40 was used to identify lymphatic endothelial cells in contrast to CD-34 identification of endothelial cells of blood vessels. Optic nerves obtained from 10 enucleation and 2 exenteration specimens submitted for routine pathology. Paraffin-embedded sections of human optic nerve were immumostained with the lymphatic specific endothelial marker D2-40 and the vascular specific endothelial marker CD-34, using a double-staining method. Results: Immunostaining with the lymphatic selective marker D2-40 positively demonstrated lymphatic vessels in the dura mater of the optic nerve. CD-34 counter-immunostaining identified blood vessels as separate vascular structures within the optic nerve meninges and adjacent ocular tissues. Positive 132-40 staining of the arachnoid mater in a nonvascular pattern was identified. Conclusions: Vessels with features compatible with lymphatic vessels were demonstrated by means of a selective monoclonal immunohistochemical marker for lymphatic endothelium in the dura mater of the human optic nerve.