The Correlation Between Interleukin 33 And Psoriasis: Systematic Review And Meta-analysis

BackgroundPsoriasis is a fairly common genetic,auto-immune disorder with a global prevalence of 2-3%.Patient reported symptoms include,scaling of the skin in 92%,pruritis in 72%,erythema in 69%,fatigue in 27%,swelling in 23%,burning in 20% and bleeding in 20% of individuals.Interleukins are secreted proteins that assists in intercellular communication.These are a type of cytokines that are produced by immune cells.Some ILs that have been associated with psoriasis are ILs 1,6,8,12,15,17 A,18,19,20,22,23 and 36 IL 33 is a new member of the IL-1 family produced by epithelial,endothelial,and fibroblast-like cells in both normal and inflamed-states.It binds with ST2 receptors and imparts various effect on mast cells,Treg cells,Th2 cells and NKT cells and performs vital functions such in homeostasis,infectious,inflammatory,metabolic,and neoplastic disease.In the recent years,research has revealed that normal healthy skin has low amount of lesional IL-33 concentration compared to human psoriatic plaques.ObjectiveTo investigate the relation between serum IL-33 levels and psoriasis.MethodsThe methodological design of this study was a systematic review and meta-analysis.Search strategies were created and used to identify relevant records in Pub Med,Google Scholar,The Cochrane Central Registry of Controlled trials(CENTRAL).To identify any records,snowballing was performed by going through the reference lists of systematic reviews and included studies.Screenings were performed using inclusion and exclusion criteria and studies were accepted into the review.Pre-developed and piloted data extraction forms were used to collect data from the study and to perform quality assessment.The data were analyzed using narrative synthesis and meta-analysis.ResultsA total 834 search records were identified of which six observational studies qualifying the inclusion and exclusion criteria were accepted in this systematic review.A total of 229 psoriatic individuals and 243 healthy individuals were included.Among the six studies,three studies were of moderate quality and three were poor quality.The range of serum IL-33 levels among the two groups were found to be 0.35 pg/ml to 586 pg/ml in the psoriatic group and 0 pg/ml to 87.7 pg/ml in the healthy control group.Although five studies out of the six reported statistically significant differences in IL-33 levels among the two-study population,this meta-analysis pooled the result to find out that there was no significant relation.However,there were significant heterogeneity among the included studies.Moreover,there were significant publication bias.ConclusionThis systematic review concluded that there is no significant difference between serum IL-33 levels in psoriatic population in comparison to healthy controls.This adds to the evidence however there is still gap in research as there is a dearth of high-quality observational research with uniform research and investigational methodology that measure the serum IL-33 levels.