Increased IL-6 production by monocytes and keratinocytes in patients with psoriasis.
Interleukin-6 (IL-6) is a multifunctional inflammatory cytokine that is produced by monocytes and keratinocytes upon stimulation. Because psoriasis is a skin disease characterized by a hyperproliferative activity of keratinocytes and an inflammatory infiltrate, in the present study IL-6 production of monocytes and keratinocytes of patients with psoriasis was investigated. Peripheral blood mononuclear cells (PBMC) derived from psoriatics, atopics, and healthy controls were incubated for 24 h and, subsequently, supernatant IL-6 activity was measured using an IL-6-dependent hybridoma cell line (B9). Compared to controls and atopics, PBMC of psoriatics produced significantly increased amounts of biologically active IL-6. These findings were also confirmed by Western blot analysis using a specific antiserum directed against IL-6. Moreover, when the sera of the same patients were tested for IL-6 activity, sera of psoriatics contained significantly elevated amounts of circulating IL-6 in comparison to samples from atopics and healthy controls. In contrast to normal or uninvolved skin, keratinocytes in psoriatic lesions were remarkably positive for IL-6 as detected by immunohistochemistry and in situ hybridization. In addition, IL-6 also was found to induce its own synthesis and release by monocytes. These findings indicate that keratinocytes and monocytes in psoriasis are activated to produce increased amounts of IL-6, which may be one of the mediators involved in the regulation of both local and systemic inflammatory reactions occurring in skin diseases such as psoriasis.
Neuner
P
P
Department of Dermatology II, University of Vienna, Austria.
Urbanski
A
A
Trautinger
F
F
Möller
A
A
Kirnbauer
R
R
Kapp
A
A
Schöpf
E
E
Schwarz
T
T
Luger
T A
TA
D000328:Adult; D002478:Cells, Cultured; D005260:Female; D006801:Humans; D015850:Interleukin-6 / Q000032:analysis / Q000096:biosynthesis* / Q000494:pharmacology; D015603:Keratinocytes / Q000378:metabolism*; D008297:Male; D008875:Middle Aged; D009000:Monocytes / Q000378:metabolism*; D011565:Psoriasis / Q000378:metabolism* / Q000628:therapy
D015850:Interleukin-6