Several of the induced genes, particularly proinflammatory cytokines IL1β, IL6, and PTGS2 and genes involved in antigen presentation (HLA-DRB1), have been implicated in persistent inflammation in other conditions including atopic dermatitis, psoriasis, and rheumatoid arthritis (50, 51). This evidence concerns the gene HLA-DRB1 and rheumatoid arthritis.