Role of regulatory T cells in pathogenesis and therapeutics of psoriatic arthritis

Psoriatic arthritis (PsA) is broadly defined as inflammatory arthritis associated with psoriasis, an inflammatory skin disease. Recent studies reinforce the concept of PsA as an autoimmune disease and provide a rationale for the study of regulatory T cells (Tregs) in this disease. In this chapter, we review studies on Tregs in peripheral blood Tregs and also Tregs at inflammation sites, namely, skin lesions and arthritic joints, where pro-inflammatory cytokines are likely to impair Tregs suppressive function or to render effector T cells resistant to suppression by Tregs. Tregs may be targeted therapeutically and antiinflammatory agents, low-dose interleukin-2, tolerogenic dendritic cells, dietary supplements, or restoring gut dysbiosis to increase their presence in PsA.