Interleukin-19 upregulates keratinocyte growth factor and is associated with psoriasis.
BACKGROUND
Interleukin (IL)-19, a member of the IL-10 family, signals through the IL-20R1/IL-20R2 heterodimer, which is shown to be involved in abnormal keratinocyte differentiation and proliferation. Little is known about its in vitro biological functions or its role in psoriasis.


OBJECTIVE
To investigate the role of IL-19 in the psoriatic process.


METHODS
The expression of keratinocyte growth factor (KGF) transcripts was measured by polymerase chain reaction in CD8+ T cells treated with IL-19. Next, we developed monoclonal and polyclonal antibodies to measure the levels of IL-19 in the sera of patients with psoriasis and healthy volunteers using an enzyme-linked immunosorbent assay. In addition, we performed immunohistochemical staining on psoriatic skin and normal controls.


RESULTS
We found that IL-19 upregulated KGF transcripts on CD8+ T cells. Patients with psoriasis had a lower level of IL-19 in serum than healthy volunteers. The difference between these two groups was statistically significant (P < 0.05). IL-19 expression was seen in basal and suprabasal keratinocytes in a continuous pattern, and was increased in psoriatic epidermis.


CONCLUSIONS
These results suggest that IL-19 plays a role in the complex pathological cytokine network in psoriasis.
Li
Hsing-Hui
HH
Institute of Basic Medical Sciences, Medical College, National Cheng Kung University, no. 1 Ta-Hsueh Road, Tainan 704, Taiwan.
Lin
Y-C
YC
Chen
P-J
PJ
Hsiao
C-H
CH
Lee
J Y-Y
JY
Chen
W-C
WC
Tzung
T-Y
TY
Wu
J-C
JC
Chang
Ming-Shi
MS
D018414:CD8-Positive T-Lymphocytes / Q000187:drug effects / Q000378:metabolism*; D016022:Case-Control Studies; D004797:Enzyme-Linked Immunosorbent Assay / Q000379:methods; D004817:Epidermis / Q000276:immunology* / Q000378:metabolism; D051523:Fibroblast Growth Factor 7; D005346:Fibroblast Growth Factors / Q000235:genetics* / Q000378:metabolism; D006801:Humans; D007150:Immunohistochemistry / Q000379:methods; D016753:Interleukin-10 / Q000097:blood / Q000494:pharmacology / Q000502:physiology*; D007378:Interleukins; D015603:Keratinocytes / Q000737:chemistry; D016133:Polymerase Chain Reaction / Q000379:methods; D011565:Psoriasis / Q000276:immunology* / Q000378:metabolism; D012333:RNA, Messenger / Q000032:analysis; D015854:Up-Regulation
C496453:FGF7 protein, human; C421250:IL19 protein, human; D007378:Interleukins; D012333:RNA, Messenger; D051523:Fibroblast Growth Factor 7; D016753:Interleukin-10; D005346:Fibroblast Growth Factors