Immunohistochemical Distribution of Basement Membrane Components in Healthy Conjunctiva, Conjunctiva of Patients With Glaucoma and Normal Skin

Abstract

Abstract: : Purpose: Cicatricial pemphigoid, a disease of the basement membrane zone (BMZ), involves skin and mucous membranes including the conjunctiva. It is often associated with glaucoma. The skin is typically used as a model for the BMZ without considering potential differences between skin and conjunctiva. Moreover, it is not known whether glaucoma or glaucoma treatment leads to changes in the antigen distribution of the BMZ. Methods: Normal conjunctiva (n=41) of patients aged 15–92 years and 16 conjunctival biopsies of glaucoma patients (10–90 years) under antiglaucomatous therapy were obtained during surgery. Immunohistochemistry was performed with the APAAP–method using the following antibodies: Laminin α, α1, α2, α3, ß1, ß3, γ1, γ2, γ3, Kalinin, ß4–Integrin, Collagen I, IV, VII. Results obtained in conjunctiva were compared to normal skin. Statistical analysis was performed using cross charts. Results: The BMZ of the skin stained positive for Laminin α, α1, α3, ß3, γ2, Kalinin, ß4–Integrin and Collagen IV. Laminin α2, ß1, γ1, γ3, and collagen I were diffusely distributed in the epithelium with pronounced staining of the basal epithelial layers and the BMZ. In contrary to the skin, the epithelium and the BMZ of the conjunctiva did not show staining for Laminin α2, ß1, ß3, γ2, and γ3. In comparison to the skin, blood vessels in the conjunctiva were preferentially negative for Laminin α2, ß1 and γ3. The BMZ of healthy conjunctiva exhibited significantly more often positivity for ß4–Integrin as compared to the conjunctival BMZ of glaucoma patients (p=0.03). Collagen VII only showed nonspecific staining and was therefore excluded from the evaluation. Conclusions: Characteristic differences in the antigenicity of the BMZ in normal skin, healthy conjunctiva and conjunctiva from patients with glaucoma were observed, especially for Laminin side–chains and ß4–Integrin. These differences may explain the variable involvement of skin and mucous membranes as well as the increased incidence of glaucoma in cicatricial pemphigoid.

Keywords: autoimmune disease • conjunctivitis • conjunctiva