The subepithelial band-like distribution pattern of CD4 may determine oral lichen planus in the absence of typical microscopic features

Abstract

Abstract Oral lichen planus (OLP) is a common oral mucosal disease. Oral lichenoid lesions (OLLs) are listed as differential diagnoses of OLP considering their similar clinical and pathological features. According to the updated OLP diagnostic criteria in 2016, a definitive diagnosis of OLP applies only if clinical and histopathological features both completely fit the required typical appearance. The term “histopathologically compatible with OLP” is suggested for a case where microscopic features do not show the typical appearance. This case could be an undetermined OLP or one type of OLLs. Our study aims to identify OLP from mimics by biomarkers. It is crucial for precise management because the treatment plans of OLP and OLLs are different. We only selected the defined typical OLP cases and typical OLL cases with triggers for study. Triggers include topical offending agents (OLL-agent), dental restorations (OLL-dental), and systemic offending drugs (OLL-drug). We investigated the expression intensity and distribution pattern of CD4, CD8, and CGRP in four groups by immunohistochemistry assay. The expression intensity of immune-positive cells was observed in the intraepithelial, subepithelial, and submucosal regions respectively, while only the subepithelial region recorded a distribution pattern. A total of 79 cases of OLP (24), OLL-agent (15), OLL-dental (21), and OLL-drug (19) were collected from the archive of an Oral Biopsy Service (2018-2021). The Chi-square with Yates’ correction is used for the comparison analysis. The diagnostic accuracy is evaluated by MedCalc software, which is reported according to the STARD 2015 checklist. The band-like distribution patterns of CD4 (100%), CD8 (54.17%), and CGRP (87.5%) in the subepithelial region observed in the OLP group significantly differ from OLL groups (each comparison pair, p = 0.0001). The sensitivity of CD4 (100%), specificity of CD8 (96.36%), negative predictive value of CD4 (100%), and accuracy of CD8 (95.94%) in the OLP group represented the highest rates in the diagnostic test evaluation. In conclusion, the band-like distribution pattern of CD4 in the subepithelial region may determine OLP when the biopsy specimen does not show typical microscopic features, whereas CD8 could be the second option.