Study Antigen targets Methodology Conventional diagnostic methods Diagnostic accuracy metrics Clinical utility Summary of main results Improvements in diagnostic accuracy or clinical decision-making
Noormohammadpour et al. [36] Nuclear constituents of cells Serum samples from OSF patients and healthy controls were tested for ANA positivity using IIF.
ANA positivity was correlated with clinical parameters like MMO and site of involvement 		Clinical examination and assessment of MMO and sites of involvement Prevalence of ANA positivity in OSF patients vs. healthy controls Presence of autoantibodies like ANAs, female predilection, and alterations in humoral and cellular immunity justify OSF as an autoimmune disease, providing a broader perspective to adopt therapies targeting autoimmune pathways. Significantly higher incidence of ANA (35.6%) in OSF patients compared to healthy controls.
Higher prevalence of ANA positivity in females (68%) than males. Significantly lower MMO in ANA positive OSF patients. Significantly more sites of involvement in ANA positive OSF cases.
Speckled, homogeneous and nucleolar fluorescence patterns observed in ANA positive cases 		Evidence supporting an autoimmune component in the etiopathogenesis of OSF, which can guide the development of targeted autoimmune therapies for this condition
Gupta et al. [37] PD-L1, CD8+, FOXP3+ T cells Tissue processing: formalin-fixed paraffin-embedded whole tissue sections.
Antigen retrieval: baked slides for 3 hours at 60 °C, stained using BOND RX™ Automated Stainer (Leica Biosystems; Wetzlar, Germany).
Analysis: nCounter® Analysis System (NanoString Technologies, Inc.) for immune gene expression 		Pathologic diagnosis verified by an expert oral pathologist, clinical phenotype verification, and gene expression profiling Cancer-free survival at 5 years, which was significantly lower in the proliferative leukoplakia group compared to the localized leukoplakia group (46.8% vs 83.6%) Evaluated immune cell infiltration and gene expression profiles to distinguish between proliferative and localized leukoplakia Proliferative leukoplakia exhibited a higher mean abundance of CD8+ T cells, PD-1+ T cells, and FOXP3+ Tregs compared to localized leukoplakia.
PD-L1 expression was significantly increased in proliferative leukoplakia samples.
Differential gene expression observed, including cytotoxic T-cell signatures and lower IFNγ expression in proliferative leukoplakia.
Specific gene overexpression noted for ICOS and other immune-related genes 		Distinct immunologic signature in proliferative leukoplakia, with higher levels of CD8+ T cells, Tregs, and PD-L1 expression compared to localized leukoplakia.
This provides a strong rationale for investigating PD-1/PD-L1 axis blockade as a preventative immunotherapy approach for high-risk proliferative leukoplakia
Hanna et al. [38] Not specified Tzanck smear evaluated using Giemsa and H&E staining. Histopathology and DIF used for definitive diagnosis Histopathology, DIF Sensitivity and specificity of Tzanck smear Tzanck smear as a rapid, inexpensive screening test for PV Sensitivity of Tzanck smear (both Giemsa and H&E) was 80.5% for PV. Specificity was 84.6% for Giemsa and 96.3% for H&E staining Tzanck smear can be used as a rapid screening test for PV prior to definitive histopathology and DIF testing
Petruzzi et al. [39] Dsg1 and Dsg3 ELISA to detect anti-Dsg1 and anti-Dsg3 antibodies, IIF Histopathological examination, DIF Sensitivity, specificity, accuracy, positive predictive value, negative predictive value Serological tests can be used as adjunctive tools for early detection and diagnosis of oral pemphigus Anti-Dsg3 ELISA had the best diagnostic performance (75% sensitivity, 100% specificity).
Anti-Dsg3 antibody titers correlated with the Oral Disease Severity Score 		Anti-Dsg3 ELISA should be considered as a first-line diagnostic test for oral pemphigus detection
Rujitharanawong et al. [40] DEJ, CBs DIF technique and slide interpretation performed according to standard criteria Clinical and histopathological examination Positive DIF yields: 79.3% in OLP, 93.3% in cutaneous LP DIF can help differentiate lichen planus from other conditions like LE and lichenoid drug reactions Deposition of immunoreactants at the DEJ was significantly greater in OLP than cutaneous LP.
Fibrin deposition with shaggy pattern at the DEJ was significantly greater in OLP than cutaneous LP.
Deposition of immunoreactants at CBs (with or without DEJ) was significantly greater in cutaneous LP than OLP.
IgM deposition at CBs was commonly detected in both groups 		Fibrin deposition with shaggy pattern at the DEJ may be the best diagnostic indicator of OLP
He et al. [41] Autoantibodies specific for PV DIF analysis of oral Tzanck smears; comparison with ELISA and IIF ELISA and IIF Sensitivity: 87.8%, specificity: 100%, area under the curve: 0.939 High diagnostic accuracy, less invasiveness, and cost-effectiveness compared to traditional methods DIF analysis of oral Tzanck smears showed high diagnostic accuracy and clinical utility for diagnosing PV, outperforming ELISA and IIF in terms of sensitivity and specificity DIF outperforms ELISA and IIF in terms of sensitivity and specificity
Mao et al. [42] Levels of CD3+ cells CD4+ cells CD8+ cells and the CD4+/CD8+ cell ratio, as well as immunoglobulins) and complement components (C3, C4) in the participants DIF examination, histopathologic tests Clinical examination, serologic testing, histopathologic tests DIF demonstrated 64.3% positive reactivity with 2 distinct distribution patterns and 8 staining patterns Enhanced understanding of OLP, potential impact on diagnosis and immune function assessment DIF and serologic testing showed significant differences in immune function markers between OLP patients and controls Combination of H&E test and DIF was found to be useful for the diagnosis of OLP. 71.2% (42/59) were diagnosed as OLP and 28.8% (17/59) were diagnosed as non-OLP using this approach
Hansen et al. [43] Not detailed Tissue processing and antigen retrieval techniques not specified in detail.
DIF samples were harvested simultaneously with light microscopic samples 		Clinical examination and histopathological analysis using light microscopy Sensitivity: 0.32, specificity: 0.88, positive predictive value: 0.68, negative predictive value: 0.61 Light microscopy alone is not sufficient for the diagnosis of OLP; combining it with DIF provides more accurate diagnosis and appropriate therapeutic regimen Light microscopy has low sensitivity but high specificity compared to DIF for diagnosing OLP.
The combination of DIF with light microscopy offers improved diagnostic accuracy and better guides treatment planning 		DIF combined with light microscopy provides more accurate diagnosis and appropriate therapeutic regimen for OLP
Korkitpoonpol et al. [44] Shaggy fibrinogen at the BMZ was the most common DIF pattern in all groups DIF analysis on tissue specimens from patients with clinical presentations of OLP Histopathological examination DIF-positivity rates among OLP, OLL, and OED groups DIF assay alone cannot reliably differentiate among OLP, OLL, and OED; histopathological examination is required 117 out of 136 patients were DIF-positive.
The highest DIF-positivity rate was in the OLP group (88.9%), followed by OLL (83.7%) and OED (81%). 		DIF assay alone is not sufficient to differentiate among OLP, OLL, and OED; careful clinicopathological correlation and long-term follow-up are necessary to diagnose and manage these lesions

ACIF = anticomplement immunofluorescence; ANA = antinuclear antibody; BMZ = basement membrane zone; C3 = complement component 3; CB = cytoid bodies; DIF = direct immunofluorescence; DG = desquamative gingivitis; Dsg1 = desmoglein 1; Dsg3 = desmoglein 3; H&E = hematoxylin and eosin; HGD = high-grade dysplasia; IIF = indirect immunofluorescence; IgG = immunoglobulin G; IgA = immunoglobulin A; IgM = immunoglobulin M; LE = lupus erythematosus; LGD = low-grade dysplasia; MMP = mucous membrane pemphigoid; MMO = maximum mouth opening; OLDR = oral lichenoid dysplasia; OLL = oral lichenoid lesions; OLP = oral lichen planus; OMLP = oral mucosal lichen planus; OSCC = oral squamous cell carcinoma; OSF = oral submucous fibrosis; PV = pemphigus vulgaris; RAS = recurrent aphthous stomatitis; T1 = tumour size classification (smallest); T4 = tumour size classification (largest); ELISA = enzyme-linked immunosorbent assay; HCV = hepatitis C virus; SCC = squamous cell carcinoma; IF = immunofluorescence