Increased IL-17 production by peripheral T helper cells after tumour necrosis factor blockade in rheumatoid arthritis is accompanied by inhibition of migration-associated chemokine receptor expression.
OBJECTIVE
The contribution of IL-17-producing Th17 cells to the pathogenesis of T-cell-mediated inflammatory disorders such as RA and atopic dermatitis (AD) has to be viewed in relation to the role of Th1/Th2 cells and long-recognized key cytokines like TNF. We aimed to study the frequency and migration-associated phenotype of peripheral Th17, Th1 and Th2 cells in healthy individuals, RA and AD patients, and to study the influence of anti-TNF therapy in RA.


METHODS
Intracellular IL-17, IFN-γ and IL-4 production and CC-chemokine receptor CCR4 and CCR6 expression were analysed flow cytometrically in peripheral memory Th cells from healthy individuals, AD and RA patients. The latter were grouped by disease activity and presence or absence of adalimumab therapy. In RA patients initiating anti-TNF therapy, cytokine production by in vitro-stimulated peripheral mononuclear cells was measured by cytometric bead array.


RESULTS
The peripheral Th17 cell frequency is elevated in AD but not in RA. In RA, Th17 cells and IL-17 production increase after anti-TNF therapy, irrespective of disease activity. Th1 cells and IFN-γ production are elevated in remission and under anti-TNF therapy. CCR6 expression is up-regulated in Th17 cells, but RA patients in remission under anti-TNF therapy have significantly lower expression than those with active disease.


CONCLUSIONS
The increase in peripheral Th17 cells in RA patients after anti-TNF therapy is accompanied by a decrease in Th17-specific CCR6 expression, which might prevent homing of these potentially pro-inflammatory cells to the synovium.
Aerts
Nicolaas E
NE
Faculty of Medicine, Department of Immunology - Allergology - Rheumatology, University of Antwerp, University of Antwerp Hospital, Campus Drie Eiken, Universiteitsplein 1, B-2610 Antwerp, Belgium.
De Knop
Kathleen J
KJ
Leysen
Julie
J
Ebo
Didier G
DG
Bridts
Chris H
CH
Weyler
Joost J
JJ
Stevens
Wim J
WJ
De Clerck
Luc S
LS
D000068879:Adalimumab; D000911:Antibodies, Monoclonal / Q000627:therapeutic use; D061067:Antibodies, Monoclonal, Humanized; D001172:Arthritis, Rheumatoid / Q000188:drug therapy / Q000276:immunology*; D016022:Case-Control Studies; D018925:Chemokines / Q000187:drug effects / Q000276:immunology*; D005260:Female; D006801:Humans; D020381:Interleukin-17 / Q000096:biosynthesis*; D008137:Longitudinal Studies; D008297:Male; D008875:Middle Aged; D019707:Receptors, Chemokine / Q000187:drug effects / Q000276:immunology*; D006377:T-Lymphocytes, Helper-Inducer / Q000276:immunology* / Q000378:metabolism*; D000079424:Tumor Necrosis Factor Inhibitors; D048069:Tumor Necrosis Factors / Q000627:therapeutic use
D000911:Antibodies, Monoclonal; D061067:Antibodies, Monoclonal, Humanized; D018925:Chemokines; D020381:Interleukin-17; D019707:Receptors, Chemokine; D000079424:Tumor Necrosis Factor Inhibitors; D048069:Tumor Necrosis Factors; D000068879:Adalimumab