Standardized extracts from Chinese herbs induce IL-10 production in human monocyte-derived dendritic cells and alter their differentiation in vitro.
BACKGROUND
The efficacy of traditional Chinese medicine (TCM) as a treatment for atopic dermatitis has been evaluated in clinical trials. Until now, the underlying mechanism of this treatment has remained completely elusive; this is particularly true of its putative effects on dendritic cells (DCs), which might play a pivotal role in the disease.


OBJECTIVE
We investigated the influence of a standardized extract from 10 Chinese herbs that was successfully used in clinical trials on the generation of monocyte-derived DCs from atopic donors.


METHODS
Detailed phenotypic and functional exploration of DCs generated in the presence of IL-4 and GM-CSF and treated with different concentrations of TCM or a placebo control was performed.


RESULTS
TCM profoundly affected the morphology and phenotype of the developing DCs. They lost their typical dendritic morphology and decreased their expression of CD1a as well as the low-affinity IgE receptor CD23. Most importantly, TCM-exposed DCs exhibited a diminished stimulatory activity toward autologous antigen-specific and allogeneic T cells while secreting high amounts of IL-10.


CONCLUSIONS
TCM induces immunopharmacologic alterations on DCs from atopic donors in vitro. These alterations might account, at least in part, for the therapeutic effect of this treatment in AD in vivo.
Novak
N
N
Department of Dermatology, Friedrich-Wilhelms-University of Bonn, Germany.
Haberstok
J
J
Kraft
S
S
Siekmann
L
L
Allam
J P
JP
Bieber
T
T
D003713:Dendritic Cells / Q000145:classification / Q000187:drug effects* / Q000276:immunology; D004365:Drugs, Chinese Herbal / Q000494:pharmacology* / Q000592:standards; D006801:Humans; D016753:Interleukin-10 / Q000378:metabolism*; D015847:Interleukin-4 / Q000096:biosynthesis; D009000:Monocytes / Q000187:drug effects*; D010641:Phenotype; D010936:Plant Extracts / Q000494:pharmacology* / Q000592:standards; D017455:Receptors, IgE / Q000096:biosynthesis
D004365:Drugs, Chinese Herbal; D010936:Plant Extracts; D017455:Receptors, IgE; D016753:Interleukin-10; D015847:Interleukin-4