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. This evidence concerns the gene IL4 and oral lichen planus.