Zeitschrift für Rheumatologie – Supplement 1 - Deutsche ...

S20
Abstracts
DR surface markers as well as for the T helper cell cytokine profi le after
PMA/ionomycin stimulation. Culture supernatants were collected
to measure cytokine concentrations by ELISA. Furthermore, synovial
fi broblasts (FLS) generated from synovial tissues of RA patients were
stimulated with ATV and RNA was analyzed by microarray analysis
and quantitative RT-PCR for the expression of proinfl ammatory chemokines
and cytokines.
Results: Flow cytometric analysis of T cell subsets revealed no signifi
cant diff erences for CD4, CD8, CD69 and HLA-DR surface marker
expression of PBMC in RA patients and healthy blood volunteers aft er
24h of ATV stimulation. However, ATV stimulation of PBMC resulted
in a signifi cant reduction of the percentage of IFN-γ expressing CD4 as
well as CD8+ T cells in PBMC cultures from RA patients (p=0.002). In
addition, this eff ect could also be demonstrated for cytokine concentrations
in culture supernatants of ATV-stimulated PBMC from RA-patients
(p=0.003). No signifi cant changes were observed for IL-4 and IL-
10 concentrations in the culture supernatants. Stimulation of cultured
FLS with 0.1 μM ATV resulted in downregulation of proinfl ammatory
cytokine (IL-6) and chemokine (IL-8) expression.
Conclusions: Our results demonstrate that in vitro stimulation with
ATV leads to a signifi cant reduction of IFN-γ expressing T cells in RA
patients and may also downregulate proinfl ammatory cytokine/chemokine
production in FLS. Th ese fi ndings provide a scientifi c rationale
for the potential use of statins as additional immunosuppressive agents
in RA.
FVFER2-4
Immune response in the synovial tissue of patients with rheumatoid
arthritis: Gene Expression Profi ling of Plasma cells.
Scheel T. 1 , Steinhauser G. 1 , Grützkau A. 1 , Grün J. 4 , Zacher J. 3 , Häupl T. 2 ,
Berek C. 1
1 Deutsches Rheuma Forschungszentrum, Berlin, 2 Department of Rheumatology,
Charité, Berlin, 3 Helios Klinikum, Berlin Buch, 4 Oligene GmbH
Rheumatoid arthritis is a chronic infl ammatory process, which leads to
swollen joints and fi nally to joint destruction. A hallmark of the disease
is a massive infi ltration of infl ammatory cells like T and B lymphocytes
and macrophages. To get further insights into the impact of the humoral
immune response for the pathogenesis of reumatoid arthritis,
gene expression of synovial plasma cells was analysed. Fozen tissue
sections were stained with a plasma cell specifi c antibody and using
Laser Capture Microdissection (Arcturus) cells were directly isolated.
Plasma cells diff usely distributed in the tissue or aggregated, associated
with lymphocytic infi ltrates and from the vicinity of blood vessels
were seperated, RNA extracted and their gene expression compared by
hybridisation to Aff ymetrix gene arrays. In addition, the V-gene repertoire
in the diff erent plasma cell subsets was analysed.
Th e method of Laser Capture Microdissection opens a new way to study
ex vivo the immune processes taking place in the chronically infl amed
synovial tissue of patients with rheumatoid arthritis. Comparison of
the gene expression of various synovial plasma cells with that of plasma
cells recirculating in the blood of healthy individuals and plasma cells
in the bone marrow will help to tease apart the contribution of plasmacells
to the complex pathogenesis of rheumatoid arthritis.
| Zeitschrift für Rheumatologie · Supplement 1 · 2006
FVFER3 8. Forum Experimentelle Rheumatologie
Teil 3: Signal transduction in autoimmunity
FVFER3-1
TNF receptor 1/2 and reverse signaling of membrane TNF participate
in T cell dependent activation of monocytes
Rossol M. 1 , Meusch U. 1 , Hauschildt S. 2 , Häntzschel H. 1 , Wagner U. 1
1 Department of Medicine IV, University of Leipzig, 04103 Leipzig,
2 Department of Immunobiology, Institute of Biology II, University of
Leipzig, 04103 Leipzig
T cell contact dependent activation of monocytes and macrophages
plays an important role in the production of the pro-infl ammatory cytokine
TNFα. In rheumatoid arthritis (RA), the pivotal role of TNF implies
that the interaction between transmembrane TNFa (mTNF) and
the TNF receptors (TNFR1 and TNFR2) might participate in the T cell
contact dependent activation of monocytes. Here we show that monocytes
receive two signals during contact with activated T cells: the fi rst
signal is triggered by mTNF on activated T cells and transduced to the
monocytes through both TNF receptors, the second signal is elicited
when TNFR2 molecules on T cells ligate mTNF on monocytes during
cell contact. Blockade of mTNF on activated T cells with an anti-TNF
antibody led to an inhibition of T cell induced monocyte TNF production
and phosphorylation of Erk. Downregulation of TNFR expression
by transfection with specifi c siRNAs results in a diminished TNFa
production. Blockade of TNFR2 on activated T cells also inhibits monocyte
TNFa production and phosphorylation of Erk, indicating that
mTNF on the monocyte surface mediates signaling. Ligation of mTNF
on monocytes by a soluble TNFR2:Ig receptor construct induces TNF
production due to reverse signaling by mTNF.
Both pathways initiated by mTNF-TNFR interaction are likely to be inhibited
by treatment with anti-TNF antibodies. Accordingly, treatment
of RA by administration of a TNF blocking antibody was found to signifi
cantly decrease T cell dependent TNF production by monocytes.
FVFER3-2
Twist1 expression marks Th lymphocytes from rheumatic
infl ammatory sites
Niesner U., Albrecht I., Radbruch A.
Deutsches Rheuma Forschungszentrum, Berlin
T helper (Th ) lymphocytes are considered to be key players in rheumatic
infl ammation. Identifi cation of genes allowing the direct targeting of
chronically activated, autoreactive Th cells will allow to design specifi c
therapies of chronic infl ammation. Here, we have identifi ed the basic
helix-loop-helix transcription factor Twist1 as a marker of chronically
activated Th 1 cells. Th e activation history of a Th 1 cell is refl ected in
the expression level of twist1 as expression increases with the number
of antigenic reactivations. Accordingly, in peripheral human Th cells
expression of twist1 increases along the diff erentiation pathway, namely
from CD45RA+ naïve Th cells to terminally diff erentiated CD45RA-
CCR7- CD27- eff ector memory Th cells. Th cells isolated from the site
of infl ammation of patients suff ering from rheumatic infl ammation,
Crohn’s disease and ulcerative colitis express high levels of Twist1, but
not Th cells isolated from healthy tissue. Twist1 expression is most effi
ciently induced if B cells function as antigen presenting cells (APCs),
requires interleukin-12 (IL-12), and is dependent on STAT4 signalling,
but it is not dependent on T-bet or STAT1, i.e. interferon gamma. Gene
expression is transiently up-regulated aft er T-cell receptor engagement.
Twist1 limits expression of the pro-infl ammatory cytokines IFN gamma,
IL-2 and TNF alpha, and promotes survival of activated memory
Th 1 cells. Th us, Twist1 limits immunopathology but contributes to
chronicity of Th 1 mediated infl ammation.