A comprehensive search was done in four databases, including PubMed/Medline, Scopus, Web of Science, Cochrane Library as well as Iranian databases with key terms (“oral lichen planus” or “OLP”), (“immunoglobulin”, “IgA”, “IgG”, or “IgM”), and (“saliva”, “salivary, or “serum”) up to January 2018, without language restriction. The gene discussed is CD79A; the disease is oral lichen planus.