Salivary and Serum Interferon-Gamma/Interleukin-4 Ratio in Oral Lichen Planus Patients: A Systematic Review and Meta-Analysis.

Background and Objectives: Interferon-gamma (IFN-γ)/interleukin-4 (IL-4) ratio may indicate a change in the immune response with a potential pathological effect presented in oral lichen planus (OLP) patients. Herein, this meta-analysis evaluated the role of serum and salivary interferon-gamma/interleukin-4 ratio in the severity and development of OLP. Materials and Methods: The Scopus, Cochrane Library, PubMed, and Web of Science databases were systematically searched to retrieve the relevant studies published up from the database inception to March 2019. The crude mean difference (MD) and 95% confidence interval (CI) were calculated by RevMan 5.3 software using a random-effects model. A sensitivity analysis was performed on the results using the CMA 2.0 software. A total of 98 studies were retrieved from the databases, of which at last seven studies were included in this meta-analysis. Results: The findings showed that the pooled MDs of serum and salivary IFN-γ/IL-4 ratio were -0.22 (95% CI: -1.16, 0.72; p = 0.64) and 0.17 (95% CI: -1.50, 1.84; p = 0.84) in OLP patients compared to controls, respectively. In addition, the pooled MDs of serum and salivary IFN-γ/IL-4 ratio were -0.15 (95% CI: -0.53, 0.23; p = 0.43) and -0.39 (95% CI: -0.63, -0.15; p = 0.001) in patients with erythematous/ulcerative subtype compared to patients with reticular subtype, respectively. Conclusions: In conclusion, the results of meta-analysis demonstrated that serum and salivary IFN-γ/IL-4 ratio cannot play a major role in OLP development and severity.