Evaluation of salivary interleukin 6 interleukin 1 beta and interferon gamma in oral and mucocutaneous lichen planus patients

Lichen planus (LP) is an immune-mediated disorder affecting mucocutaneous tissues. This study aimed to evaluate and compare the salivary levels of interleukin (IL-6), interleukin-1 beta (IL-1β), and interferon-gamma (IFN-γ) in patients with oral lichen planus (OLP) and mucocutaneous lichen planus (MCLP) and to assess their correlation with disease severity. This prospective comparative study included 20 healthy controls (HCs) and 40 LP patients (20 OLP, 20 MCLP) matched for age and sex. All LP patients' diagnoses were clinically and histopathologically confirmed. Unstimulated saliva samples were collected. ELISA was used to measure cytokine levels. The clinical severity of OLP patients was assessed using the REU (reticulation/Erythema/ulceration) score. The level of IL-6 in patients with both OLP and MCLP was significantly greater than that in HCs (p < 0.001). The concentration of IL-1β was also greater in both groups than in the HC group, with no significant difference between the disease groups (p = 0.779). The IFN-γ levels in both groups were significantly greater than those in the HCs, with the levels in the MCLP group being significantly greater than those in the OLP group. IL-6 correlated with clinical severity in patients with OLP (ρ = 0.469; p = 0.037), while IL-1β correlated negatively with MCLP (ρ = -0.490; p = 0.028). This study is original in that it compared salivary cytokine profiles (IL-6, IL-1β, and IFN-γ) between OLPs and MCLPs. MCLP is associated with higher IFN-γ levels, and OLP is associated with higher IL-6 levels, indicating that these cytokines are promising biomarkers of disease severity. These findings support cytokine profiling as a noninvasive diagnostic tool and pave the way for personalized treatments.