Direct immunofluorescence in oral lichen planus and oral lichenoid reactions

Objective: To aid in differentiation of the two lesions, direct immunofluorescence was used to examine the fluorescence patterns in oral lichen planus and oral lichenoid reactions and to compare the degree of intensity of their fluorescence. Method and materials: Thirty patients participated in this study. Oral mucosal biopsy specimens were obtained from the edge of fresh lesions and were hemisected. One of the sections was placed in 10% neutral buffered formalin for standard light microscopic examination and the other was washed in phosphate-buffered saline and transferred to Michel's transport media for direct immunofluorescence examination. Results: Fibrinogen was deposited in specimens from 14 of 15 patients diagnosed with oral lichen planus; lesions showed an intense positive fluorescence that outlined the basement membrane zone. Eight of 10 sections from oral lichenoid reactions exhibited fibrinogen deposition along the basement membrane zone; the specimens showed a less intense, homogenous linear fluorescence. Specimens from five control samples showed no fluorescence. Conclusion: Fibrinogen was deposited at the basement membrane zone in both oral lichen planus and suspected oral lichenoid reactions, but the fluorescence was less intense in the oral lichenoid lesions.