Expression of K2P5.1 potassium channels on CD4+ T lymphocytes correlates with disease activity in rheumatoid arthritis patients

• Published in: Arthritis research & therapy 2011-02, Vol.13 (1), p.R21-R21, Article R21
• Main Authors: Bittner, Stefan, Bobak, Nicole, Feuchtenberger, Martin, Herrmann, Alexander M, Göbel, Kerstin, Kinne, Raimund W, Hansen, Anker J, Budde, Thomas, Kleinschnitz, Christoph, Frey, Oliver, Tony, Hans-Peter, Wiendl, Heinz, Meuth, Sven G
• Format: Article
• Language: English
• Subjects: Arthritis, Rheumatoid - immunology; Arthritis, Rheumatoid - metabolism; Arthritis, Rheumatoid - physiopathology; Blotting, Western; CD4-Positive T-Lymphocytes - metabolism; Cell Separation; Female; Flow Cytometry; Fluorescent Antibody Technique; Humans; Male; Potassium Channels, Tandem Pore Domain - biosynthesis; Real-Time Polymerase Chain Reaction; Reverse Transcriptase Polymerase Chain Reaction
• ISSN: 1478-6362; 1478-6354; 1478-6362
• DOI: 10.1186/ar3245

CD4+ T cells express K(2P)5.1 (TWIK-related acid-sensitive potassium channel 2 (TASK2); KCNK5), a member of the two-pore domain potassium channel family, which has been shown to influence T cell effector functions. Recently, it was shown that K(2P)5.1 is upregulated upon (autoimmune) T cell stimulation. The aim of this study was to correlate expression levels of K(2P)5.1 on T cells from patients with rheumatoid arthritis (RA) to disease activity in these patients. Expression levels of K(2P)5.1 were measured by RT-PCR in the peripheral blood of 58 patients with RA and correlated with disease activity parameters (C-reactive protein levels, erythrocyte sedimentation rates, disease activity score (DAS28) scores). Twenty patients undergoing therapy change were followed-up for six months. Additionally, synovial fluid and synovial biopsies were investigated for T lymphocytes expressing K(2P)5.1. K(2P)5.1 expression levels in CD4+ T cells show a strong correlation to DAS28 scores in RA patients. Similar correlations were found for serological inflammatory parameters (erythrocyte sedimentation rate, C-reactive protein). In addition, K(2P)5.1 expression levels of synovial fluid-derived T cells are higher compared to peripheral blood T cells. Prospective data in individual patients show a parallel behaviour of K(2P)5.1 expression to disease activity parameters during a longitudinal follow-up for six months. Disease activity in RA patients correlates strongly with K(2P)5.1 expression levels in CD4+ T lymphocytes in the peripheral blood in cross-sectional as well as in longitudinal observations. Further studies are needed to investigate the exact pathophysiological mechanisms and to evaluate the possible use of K(2P)5.1 as a potential biomarker for disease activity and differential diagnosis.