Differences in basement membrane zone components of normal conjunctiva, conjunctiva in glaucoma and normal skin.

PURPOSE

To describe the distribution of basement membrane zone (BMZ) components in normal conjunctiva, conjunctiva of patients with glaucoma and normal skin.

METHODS

Thirty-five normal conjunctival biopsies and 16 conjunctival biopsies of patients with glaucoma under topical anti-glaucomatous therapy were examined by immunohistochemistry. Antibodies were directed against laminin α chains, laminin subchains α1, α2, α3, β1, β3, γ1, γ2, γ3, kalinin, β4-integrin, and collagens IV and VII. Results were compared to the antigen distribution at the BMZ in normal skin.

RESULTS

The BMZ of skin stained positive for all antibodies tested. In contrast to skin, the BMZ of normal conjunctiva was negative for laminin subunits α2, β1, β3, γ2 and γ3 in most or all specimens. Positive findings at the conjunctival BMZ of patients with glaucoma were comparable to normal conjunctiva for laminin α, α1, β3, γ1, γ3, laminin 5, β4-integrin, collagen IV and collagen VII. However, staining of the BMZ with antibodies to laminin β1 (p=0.002) and γ2 (p=0.017) was seen in a significantly higher rate in glaucoma compared to controls.

CONCLUSION

Characteristic differences exist in the antigenicity of the BMZ in normal skin, normal conjunctiva and conjunctiva from patients with glaucoma, especially for laminin subchains. These differences may explain the variable ocular involvement in diseases of the BMZ. Moreover, they may explain the susceptibility of patients with glaucoma to develop mucous membrane pemphigoid-like disease. Alterations in conjunctival BMZ in glaucoma may be induced by long-term topical anti-glaucoma medications including various preservation agents.