PTPN2 and psoriasis: The PP02 group had more up-regulated genes related to the cells of the adaptive immune system such as CTLA-4 (associated with modulation of T helper responses), IFI30 (involved in MHC Class II antigen processing), IL4IL (immunomodulatory enzyme produced by dendritic cells), PTPN2 (associated with autoimmune disorders such as type 1 diabetes mellitus and Crohn’s disease) and most interestingly SERPINB8, which has been identified through Genome-Wide Association Studies (GWAS) as a new psoriasis susceptibility locus in the Chinese population [41].