Direct Immunofluorescence in Oral Lichen Planus

Introduction: Oral lichen planus (OLP) is a common immunemediated oral mucosal disease. Diagnosis of OLP depends mainly on both clinical and histopathological features. Direct immunofluorescence (DIF) is a useful investigation method to distinguish between similar lesions and to confirm diagnosis in cases of uncharacterized features. Aim: The purpose of this study was to evaluate the prevalence and pattern of DIF in a group of Thai patients with OLP. Materials and Methods: Records of clinically and histologically diagnosed OLP patients attending the Oral Medicine Clinic, Faculty of Dentistry, Mahidol University, Bangkok, Thailand were consecutively reviewed for DIF results. The DIF patterns in these patients were analysed. Results: There were 82 atrophic and/or erosive OLP patients with a mean age of 51.6 years. Male to female ratio was 1: 5. Of these, 82.9% showed positive DIF. Buccal mucosa was superior to the gingiva and palate in terms of sensitivity for DIF. All specimens except one (98.5%) demonstrated deposition of fibrinogen at the basement membrane zone (BMZ) in a shaggy pattern. The most common DIF pattern was shaggy fibrinogen at BMZ with IgM deposition on the colloid bodies (CB) (35.3%) followed by shaggy fibrinogen along BMZ (27.9%). Conclusion: The prevalence of positive DIF in Thai OLP patients was 82.9%. The most common finding was shaggy fibrinogen at BMZ. The typical pattern was shaggy fibrinogen along BMZ with or without positive IgM at CB. DIF pattern could be evaluated for the diagnosis of OLP lacking clinical and/or histopathological characteristic features.