Mozaffari HR, et al. - Via a systematic review and meta-analysis, researchers examined the association of several oral lichen planus (OLP) variants with interleukin 4 (IL-4) concentrations in serum and saliva. They searched Cochrane Library, Scopus, PubMed, and Web of Science and identified 108 relevant studies, of which only 10 were included and analyzed in quantitative synthesis. In patients with erosive, erythematous, bullous, and ulcerative variants of OLP vs patients with reticular OLP, 1.30 pg/mL and 1.83 pg/mL was the respective pooled mean difference of serum and salivary IL-4 level. Elevated serum and salivary IL-4 levels were found in OLP patients, suggesting the possible value of IL-4 as a potential salivary biomarker for the disease. By contrast, awareness regarding the possible impact of even other factors (eg, secondary infection) on IL-4 levels is critical among clinicians.