Three decades of psoriasis research: where has it led us?
Psoriasis is a common chronic skin disease. Its pathogenesis has intensively been investigated in the last 3 decades. In the 1970s, the observed increased proliferation of keratinocytes and their altered differentiation were considered to be the most important signs and causes of psoriatic skin lesions. Since the early 1980s, T cells slid into the focus of psoriasis research. It was then postulated that a subpopulation of T cells, so-called T1 cells, and their prominent cytokine interferon-gamma, had a dominant role in the pathogenesis of psoriasis. In the last decade, new data regarding macrophages and dendritic cells and the high therapeutic success of anti-tumor necrosis factor alpha biologics led to the assumption that antigen-presenting cells are important not only in the induction of psoriasis but also in its maintenance. The knowledge gained over the past 3 decades let us postulate that psoriasis is an immunologically induced, overshot, regeneration-like reaction of the skin in which various cells play a dominant role at different stages. This hypothesis is also supported by the very recent discoveries about interleukin (IL)-22, IL-20, and IL-23.
Sabat
Robert
R
Interdisciplinary Group of Molecular Immunopathology, Dermatology/Medical Immunology, University Hospital Charité, D-10117 Berlin, Germany. robert.sabat@charite.de
Sterry
Wolfram
W
Philipp
Sandra
S
Wolk
Kerstin
K
D002908:Chronic Disease; D016207:Cytokines / Q000276:immunology / Q000378:metabolism*; D003713:Dendritic Cells / Q000276:immunology / Q000502:physiology; D006801:Humans; D007371:Interferon-gamma / Q000276:immunology / Q000378:metabolism*; D015603:Keratinocytes / Q000276:immunology / Q000502:physiology*; D008213:Lymphocyte Activation; D011565:Psoriasis / Q000276:immunology / Q000503:physiopathology; D012867:Skin / Q000276:immunology; D016176:T-Lymphocyte Subsets / Q000276:immunology / Q000378:metabolism; D014409:Tumor Necrosis Factor-alpha / Q000276:immunology / Q000378:metabolism*
D016207:Cytokines; D014409:Tumor Necrosis Factor-alpha; D007371:Interferon-gamma