ar1611 ARJ Poster presentation <p>Gene expression in chronically activated Th cells</p> Niesner U Albrecht I Baumgrass R Janitz M Lehrach H Haeupl T Grun J Burmester GR Grutzkau A Radbruch A

German Arthritis Research Centre, Berlin, Germany

Department of Vertebrate Genomics, Max Planck Institute for Molecular Genetics, Berlin, Germany

Department of Rheumatology and Clinical Immunology, Charité University Medical Centre, Berlin, Germany

Oligene Inc., Berlin, Germany

 Arthritis Research & Therapy <p>25<sup>th</sup> European Workshop for Rheumatology Research</p> The organizer would like to thank the following companies who have generously supported the meeting: Abbott Immunology (Main sponsor), Bristol-Myers Squibb, Schering-Plough, Wyeth, AstraZeneca, MSD, Amgen Meeting abstracts <p>25<sup>th</sup> European Workshop for Rheumatology Research</p> Glasgow, UK 24-27 February 2005 1478-6354 2005 7 Suppl 1 P90 10.1186/ar1611 11 1 2005 17 2 2005 2005 BioMed Central Ltd

Th lymphocytes are considered to be key players in chronic inflammation. Upon repeated re-stimulation and differential instruction, they can develop a stable memory for the expression of distinct genes coding for cytokines, chemokines, adhesion molecules, and so on. This functional memory contributes considerably to the chronicity of inflammation and its eventual refraction to therapy.

Here, we describe the global gene expression profiles of in vitro repeatedly reactivated murine Th1 and Th2 cells, and compare them with those of naïve and once activated Th1 and Th2 cells, both before and after re-stimulation (Fig. 1).

Among differentially expressed genes is a novel transcription factor, which down-modulates NF-κB signalling and is exclusively expressed in repeatedly re-activated Th1 cells. High expression of this gene can be detected in Th cells isolated from the site of inflammation of patients suffering from distinct forms of rheumatic diseases or ulcerative colitis, but not in Th cells isolated from healthy tissue or from blood.

Expression of this gene in Th cells at the site of inflammation highlights the role of chronic T-cell activation in chronic inflammation and may represent an endogenous mechanism to limit inflammation. Apart from its diagnostic value, this molecular pathway also points to a new therapeutic target.

<p>Figure 1</p>

Hierarchical clustering of differentially expressed genes among doublets of the nine investigated cell populations (w, weeks in culture; res, 3 hours re-stimulated) using Affymetrix Mouse Genome 430A 2.0 Arrays and DNA-Chip Analyzer (dChip)

Hierarchical clustering of differentially expressed genes among doublets of the nine investigated cell populations (w, weeks in culture; res, 3 hours re-stimulated) using Affymetrix Mouse Genome 430A 2.0 Arrays and DNA-Chip Analyzer (dChip).