Diagnostic significance of direct immunofluorescence in oral lichen planus

Oral lichen planus (OLP) is a common chronic inflammatory mucosal disease. Diagnosis of OLP depends mainly on clinical and histopathologic features. Objective: The purpose of this study was to evaluate the value of Direct immunofluorescence (DIF) in the diagnosis of OLP. Methods: Files of OLP patients attending Oral Medicine Clinic, Faculty of Dentistry, Mahidol University from 1995-2005 were reviewed for diagnostic methods including medical and dental history, clinical, histopathologic and DIF examinations. Results: Of the total 181 OLP patients, 75 patients had biopsy performed for histopathologic and DIF examinations. Histopathologic diagnosis revealed 42 cases of OLP, 17 cases of compatible with or suggestive of OLP and 16 cases of inflamed oral mucosa. The typical DIF patterns for OLP were found in 58 of 75 cases (77.3%). These included shaggy fibrinogen along the basement membrane zone or fibrinogen deposit and IgM- or less often IgA positive cytoid-like bodies in the lower epithelium and papillary submucosa or IgM-positive without fibrinogen deposit. Complement component C3 was also positive in 11/58 cases. Negative DIF was observed in 22.7% (17/75). The typical DIF patterns were presented in 73.8% (31/42) of histopathologic diagnosed OLP, in 88.2% (15/17) of compatible of OLP cases and in 75% (12/16) of inflamed oral mucosal cases. Therefore, the diagnosis of OLP was established by a typical DIF pattern in 81.8% (27/33) of inconclusive histopathologic findings. Conclusion: DIF is a valuable diagnostic test in most OLP cases with inconclusive diagnosis by histopathologic examination.