Costimulatory molecules in ocular cicatricial pemphigoid

PURPOSE: To examine normal and inflamed conjunctiva from patients with ocular cicatricial pemphigoid (OCP) for the presence of costimulatory molecule CD28 and its ligands B7-1 (CD80) and B7-2 (CD86). METHODS: Conjunctival biopsy specimens from 12 patients with OCP and from five healthy persons undergoing cataract surgery were analyzed by light microscopy and immunohistochemical examination with monoclonal antibody probes for CD28, B7-1, and B7-2 molecules and for mononuclear cell subtypes. RESULTS: Epithelium of OCP conjunctiva showed more Langerhans' cells, B7-1-positive (+) cells, and B7-2 expression (ratio of B7-2-positive cells to antigen-presenting cells). In the substantia propria, OCP specimens showed significantly increased numbers of T cells (CD3 +), macrophages (CD68+), CD28+ cells, B7-2+ cells (CD86+), Langerhans' cells (CD1a), and B7-1+ cells (CD80). Most of the B7-2+ cells, macrophages, and Langerhans' cells were located subepithelially. B7-2 expression was significantly higher in OCP conjunctival substantia propria compared with normal conjunctiva. CONCLUSIONS: The results of this study indicate that the expression of the costimulatory molecule B7-2 is upregulated in conjunctiva of patients with active OCP. This increased subepithelial B7-2 expression may contribute to the sustained immune activation in OCP conjunctiva.