A role for T cell-derived interleukin 22 in psoriatic skin inflammation.
Interleukin (IL)-22 is a T cell-derived cytokine that has been reported recently to induce cutaneous inflammation in an experimental murine model of psoriasis, and to induce in vitro an inflammatory-like phenotype. In the present study, we assessed the presence of IL-22 and the IL-22 receptor 1 (IL-22R1) in skin lesions, skin-derived T cells, as well as IL-22 levels in sera from patients with psoriasis. IL-22R1 and IL-10R2 transcripts are expressed at a similar level in psoriatic and healthy skin. In contrast, IL-22 mRNA expression was up-regulated in psoriatic skin lesions compared to normal skin, whereas IL-22 mRNA levels in peripheral blood mononuclear cells from psoriatic patients and normal subjects were similar. Circulating IL-22 levels were significantly higher in psoriatic patients than in normal subjects. T cells isolated from psoriatic skin produced higher levels of IL-22 in comparison to peripheral T cells isolated from the same patients. IL-10 was expressed at similar levels in skin biopsies and peripheral blood mononuclear cells of psoriatic patients and normal subjects. Finally, we show here that supernatants of lesional psoriatic skin-infiltrating T cells induce an inflammatory response by normal human epidermal keratinocytes, resembling that observed in psoriatic lesions. Taken together, the results reported in this study indicate that IL-22 is a cytokine produced by skin-infiltrating lymphocytes that is potentially involved in initiation and/or maintenance of the pathogenesis of psoriasis.
Boniface
K
K
Université de Poitiers, CHU de Poitiers, UPRES-EA 3806, Laboratoire Cytokines et Inflammation, Poitiers, France.
Guignouard
E
E
Pedretti
N
N
Garcia
M
M
Delwail
A
A
Bernard
F-X
FX
Nau
F
F
Guillet
G
G
Dagregorio
G
G
Yssel
H
H
Lecron
J-C
JC
Morel
F
F
D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D002478:Cells, Cultured; D005260:Female; D020869:Gene Expression Profiling / Q000379:methods; D006801:Humans; D018836:Inflammation Mediators / Q000378:metabolism; D007378:Interleukins / Q000096:biosynthesis / Q000235:genetics / Q000276:immunology*; D015603:Keratinocytes / Q000276:immunology; D008297:Male; D008875:Middle Aged; D011565:Psoriasis / Q000276:immunology*; D012333:RNA, Messenger / Q000235:genetics; D018123:Receptors, Interleukin / Q000378:metabolism; D020133:Reverse Transcriptase Polymerase Chain Reaction / Q000379:methods; D012867:Skin / Q000276:immunology; D013601:T-Lymphocytes / Q000276:immunology*; D015854:Up-Regulation; D000097043:Interleukin-22
D018836:Inflammation Mediators; D007378:Interleukins; D012333:RNA, Messenger; D018123:Receptors, Interleukin; D000097043:Interleukin-22; C415369:interleukin-22 receptor