CELL PROLIFERATION AND CYTOKINE INDUCTION BY TNF-alpha OF PSORIATIC KERATINOCYTES ARE NOT DIFFERENT FROM NORMAL KERATINOCYTES IN VITRO.
BACKGROUND
Recent studies indicate that various cytokines including tumor necrosis factor-alpha (TNF-alpha) play an essential role in the induction and maintenance of psoriatic lesion.


OBJECTIVE
To compare the cell proliferation of keratinocytes by various cytokines and TNF-alpha-induced cytokine secretion among normal keratinocytes, uninvolved, and involved keratinocytes.


METHODS
The keratinocytes from normal skin, uninvolved, and involved psoriasis were cultured in the presence of IL-6, IL-8, epidermal growth factor (EGF), hepatocyte growth factor (HGF), transforming growth factor-alpha (TGF-alpha) epiregulin, amphiregulin, and TNF-alpha and then MTT assay for keratinocytes proliferation was performed. Furthermore, TNF-alpha-induced secretion of IL-6, IL-8, EGF, HGF, TGF-alpha, epiregulin, and amphiregulin were compared among these keratinocytes.


RESULTS
IL-6, IL-8, EFG, TGF-alpha, epiregulin, and amphiregulin, but not TNF-alpha increased keratinocyte proliferation of normal, psoriatic uninvolved, and involved skin. The increased cell proliferation by these cytokines and growth factors were not different among the keratinocytes derived from normal skin, uninvolved, and involved psoriasis. The significant induction of TNF-alpha increased IL-6, IL-8, EGF, HGF, TGF-alpha, epiregulin, and amphiregulin, but the increase in these cytokines and growth factors were not different among normal skin, uninvolved, and involved psoriasis.


CONCLUSIONS
Cell proliferation by various cytokines and growth factors and TNF-alpha-induced cytokine secretion are not different between normal and psoriatic keratinocytes.
Takahashi
Hidetoshi
H
Department of Dermatology, Asahikawa Medical College, 2-1-1-1 Midorigaokahigashi, Asahikawa 078-8510, Japan.
Tsuji
Hitomi
H
Hashimoto
Yoshio
Y
Ishida-Yamamoto
Akemi
A
Iizuka
Hajime
H