Pathogenic and protective roles of cytokines in pemphigus: A systematic review

•Pemphigus is a rare autoimmune disease, affecting the skin and mucous membranes.•Cytokines could have a pathogenic and protective role in pemphigus.•Increased and decreased levels of different cytokines were reported in pemphigus patients.•Manipulation of cytokine levels could be used as the treatment of pemphigus. Pemphigus is a rare and life-threatening group of blistering autoimmune diseases that affects the skin and mucous membranes. There are two major subtypes of pemphigus, including pemphigus vulgaris (PV) and pemphigus foliaceus (PF); each has different clinical manifestations. Pemphigus cannot be considered as a single disease and each patient may have a specific immunological profile. There are a lot of studies available regarding the role of different cytokines in the pathogenesis of pemphigus, although the data are not coherent between different studies. In this study, a systematic review from inception to December 25, 2019, through the MEDLINE/PubMed database had been performed to address several aspects of cytokines’ roles in PV and PF. As a result, 57 studies from 352 initially found records, containing 26 cytokines had met the inclusion criteria. We found different pieces of evidence in favor of increased levels of TNF-α, TGF-β, interleukin (IL)-8, IL-10, IL-12, IL-17, IL-21; while decreased levels of IL-2 and IL-23 in pemphigus patients. Regarding other cytokines, such as IFN-γ, IL-5, IL-15, IL-22, there are controversial results. Different studies suggested the association of TNF-α and IL-6 with disease activity and autoantibodies values. However, there is uncertainty regarding the role of IFN-γ, IL-2, IL-15, IL-27, and IL-33. Treatments with immunosuppressive agents may decrease IL-1, IL-6, IL-8, IFN-γ, IL-33, IL-17 levels. In conclusion, cytokines are deeply involved in PV and PF pathogenesis, and targeting specific cytokines may lead to development of more promising treatments for pemphigus.