Direct immunofluorescence for oral lichen planus

Summary: Abstract Body: Introduction: Oral lichen planus (OLP) is a chronic, inflammatory mucocutaneous disease characterized histologically by lymphocytic lichenoid infiltrate and shaggy fibrinogen depositions near the basement membrane zone with direct immunofluorescence (DIF).1 There is limited data describing DIF utility in OLP and DIF changes across OLP phenotypes. We aimed to describe the results of DIF in cases of clinically and histologically confirmed OLP. Methods: We retrospectively evaluated OLP cases seen at the University of Utah from 01/2011-07/2023. OLP diagnosis was made via histology and clinical appearance. OLP phenotype, etiology, patient demographics, and DIF data were collected. DIF data was extracted from clinical reports made by experienced dermatopathologists with extensive DIF’s experience. Data was analyzed descriptively, and we used logistic regression to compare odds of DIF positivity across OLP phenotypes and etiologies. Results: We identified 122 cases of OLP with DIF were identified (100 idiopathic, 10 allergic contact, 6 drug-induced). 43 were erosive at >50% of visits, 18 had extensive disease (>50% mouth affected), buccal mucosa was most affected (95/122). 95 patients were female, the median age was 62, and 112/122 were white. 75/122 cases were reported as positive and 26/122 were read as negative (sensitivity 61.5%, false negative rate 21.3%). We found no evidence for differences in DIF positivity across OLP etiologies nor disease phenotypes (p<0.05). Conclusion: While DIF is critical for ruling out other disease causes, in our cohort it had low sensitivity and a high false negative rate suggesting that DIF should not be relied on for OLP diagnosis. References: Tekin B, Hardway H, Lehman JS, Direct immunofluorescence testing for lichen planus: A retrospective cohort study of 1747 specimens, Journal of the American Academy of Dermatology (2024), doi: https://doi.org/10.1016/j.jaad.2024.06.096. Justin Lyon¹, Annabelle Huntsman¹, Rachel Seifert¹, Christiaan Noot¹, Charles Teames¹, David West¹, Jamie Rhoads¹, Christopher Hull¹, John Zone¹, Zachary Hopkins¹ 1. Dermatology, University of Utah Health, Salt Lake City, UT, United States. Clinical Research: Epidemiology and Observational Research