Extracellular vesicles as biomarkers and disease mediators in lichen planus: a systematic review & meta-analysis

Background Lichen Planus (LP) is a chronic inflammatory disorder that can affect the skin, hair, nails, and mucous membranes. Oral lichen planus (OLP), the most common LP subtype, is a disease of the oral mucosa, often diagnosed through clinical examination and histopathological confirmation. Extracellular vesicles (EVs) transfer proteins, lipids, and nucleic acids among cells and have become increasingly studied for their potential as minimally invasive diagnostic biomarkers and therapeutic agents in inflammatory and autoimmune diseases. Methods PUBMED and Embase were searched from inception through June 27th, 2026. Human studies investigating EV-associated miRNA or protein biomarkers in LP and its subtypes were included, with risk of bias assessed using a modified Newcastle-Ottawa Scale. Diagnostic accuracy was evaluated using receiver operating characteristic (ROC) and BRMA models when sufficient data were available. Results Ten articles met the inclusion criteria, encompassing biomarker discovery, functional, and mechanistic studies of EVs in OLP. These included studies (n = 10) comprised 298 individuals with LP (weighted mean age 50.7 years; 61.5% female) and 194 controls (weighted mean age 47.8 years; 58.5% female). OLP-specific cohorts (n = 9 studies) included 261 individuals with OLP (weighted mean age 50.7 years; 61.4% female). Although no individual EV-associated miRNAs or proteins overlapped across studies, EV-associated miRNAs demonstrated substantial heterogeneity, while EV-associated protein findings centered on pathways related to antigen presentation, inflammatory signaling, and immune activation. Several candidate biomarkers, including miR-4484, miR-34a-5p, GJA1, PDIA3, and Cx43, showed potential diagnostic or prognostic relevance. ROC analyses demonstrated good diagnostic utility for miR-4484 (AUC = 0.81), and the combination of GJA1 and Cx43 showed the strongest discriminatory ability (AUC = 0.892). The diagnostic accuracy meta-analysis showed good discrimination (pooled AUC = 0.89). Functional and mechanistic studies suggested that EVs may actively contribute to OLP pathogenesis through promoting epithelial injury and activating inflammatory signalling pathways. Conclusions EV-associated miRNAs and proteins are potential biomarker candidates for LP and may provide insight into the inflammatory and immune mechanisms underlying disease pathophysiology. Functional and mechanistic evidence further suggests that EVs may play an active role in disease progression. However, current evidence has limitations such as small sample sizes and methodological heterogeneity. Larger, standardized, and longitudinal studies are needed to v