The Subepithelial Bandlike Distribution Pattern of the CD4 Biomarker May Determine Oral Lichen Planus in the Absence of Typical Microscopic Features

Given higher compatible rates between oral lichen planus (OLP) and oral lichenoid lesions (OLLs) in histopathological and clinical features, this study aims to delineate a boundary between equivocal OLP and OLLs by biomarkers. The updated OLP diagnostic criteria in 2016 was our guideline in defining study cases of typical OLP and typical OLL with triggers, which include topical offending agents (OLL-agent), dental restorations (OLL-dental), and systemic offending drugs (OLL-drug). The expression intensity and distribution patterns of CD4, CD8, and CGRP in four groups were detected by immunohistochemistry assay (IHC). A total of 79 cases including OLP (24), OLL-agent (15), OLL-dental (21), and OLL-drug (19) were collected from an oral biopsy laboratory. Band-like distribution patterns of CD4 (100%, score 3), CD8 (54.17%, score 2), and CGRP (87.5%, score 3) in the subepithelial regions of the OLP group significantly differ from the OLL groups (each comparison pair, p = 0.0001). The sensitivity of CD4 (100%), specificity of CD4 (83.64%), negative predictive value of CD4 (100%), and accuracy of CD4 (83.80%) in the OLP group provide results for the diagnostic test evaluation. The band-like distribution pattern of CD4 in the subepithelial region may determine OLP when the biopsy specimen does not show typical microscopic features.