Principles of biological therapy in psoriasis.

Psoriasis is a chronic, systemic T-cell mediated autoimmune skin disease, potentially associated with arthritis. The new understanding of immunopathogenesis and inflammatory cytokine pathways was actually the rationale for developing and introducing biological drugs in the treatment of moderate to severe psoriasis and psoriatic arthritis. Different from the traditional systemic drugs that impact the entire immune system, bio-logics target only specific points of the immune system. This review focuses on five biologics which target either T-cells (alefacept) or TNF-alpha (etanercept, adalimumab and infliximab) or interleukin IL-12/IL-23 (ustekinumab)--their efficacy, safety, patient monitoring and recommended dosage. The purpose of the treatment guidelines presented here is to provide a high standard of continuing care of psoriasis and psoriatic arthritis patients.