Background: Chronic progressive conjunctival cicatrisation is poorly understood, and therapy of this condition remains difficult. This study assessed the value of immunohistochemical investigations in the evaluation of patients who present with chronic cicatrising conjunctivitis similar to cicatricial pemphigoid (CP).
Methods: Bulbar conjunctival biopsies from 36 patients with acute (n = 5), subacute (n = 13) and chronic (n = 18) ocular disease were studied. The biopsy was retaken in 7 patients to evaluate the present immunological findings in comparison with a biopsy more then 5 years ago. All the specimens were investigated for the presence of immunoglobulins and complement at the epithelial basement membrane, and the phenotype of the inflammatory cellular infiltrate was analysed. Twenty-nine patients were evaluated for the presence of circulating IgG-anti-basement membrane zone antibodies.
Results: CP was confirmed by immunoglobulins and/or complement deposition at the epithelial basement membrane in 11 patients (31%). IgA was found to be the most frequent deposit. Eleven CP patients, mainly those with active or "burnt-out" disease, showed absence of immunoglobulins and/or complement at the conjunctival basement membrane. In 14 of 36 patients, conjunctival cicatrisation was subsequently felt to be caused by conditions other than CP. The cellular phenotype in the subepithelial conjunctiva was unspecific, but in CP the disease activity was reflected by the number of neutrophils and macrophages. Circulating IgG antibodies were found in none of the patients' serum.
Conclusion: Immunoglobulin and/or complement deposition at the epithelial basement membrane confirms the diagnosis of mucous membrane pemphigoid. Their absence, however, does not rule it out and is a frequent feature in very active conjunctival disease or after immunosuppressive treatment. The analysis of the cellular phenotype in mucous membrane pemphigoid may be useful in the assessment of disease activity but does not help in determining the underlying disease process causing the cicatrising conjunctivitis.