Current Treatment of Psoriasis with Biologics

Psoriasis is a chronic inflammatory skin disease with a significant number of patients suffering from additional joint involvement and other co-morbidities. The precise pathomechanisms of this disease are still unknown. But based on recent findings a picture emerges putting a new subset of inflammatory T cells, so-called Th17 T cells, into the centre of psoriasis pathogenesis. These cells secrete interleukin (IL)-17 and a further set of so-called Th17 cytokines such as IL-21 and IL-22, the latter of which appears to significantly contribute to the epidermal changes observed in this disease. Differentiation and maintenance of Th17 cells depends on IL-23 and transforming growth factor (TGF)-β, secreted by activated monocytes or macrophages within the dermal compartment. In recent years, a plethora of new treatment approaches was introduced using antibodies or small molecule inhibitors specifically targeting inflammatory cytokines, cellular receptors or signalling mechanisms. Based on current results from large clinical trials, a more individualized treatment for affected patients may be achieved in the near future. In this review, we summarize the current knowledge about treatment of psoriasis with biological agents targeting inflammatory mechanisms.