Anti-inflammatory effects of atorvastatin on peripheral blood mononuclear cells and synovial fibroblasts in rheumatoid arthritis.

Statins, such as atorvastatin (ATV), are 3-hydroxy-3-methylglutaryl coenzyme A (HMG-CoA) reductase inhibitors known to exert lipid-lowering but also anti-inflammatory, effects. In this study, we analysed the in vitro effects of ATV on peripheral blood mononuclear cells (PBMCs) and fibroblast-like synoviocytes (FLS) in rheumatoid arthritis (RA), a chronic inflammatory joint disease. PBMCs isolated from 25 RA patients and 20 healthy blood donors were stimulated in vitro with 0.1 microM ATV for 24 h. PBMC cultures were analysed for cell surface markers to characterize T-cell subtypes (CD4, CD8, CD69, HLA-DR) by flow cytometry and for T helper cell type 1 (Th1) and type 2 (Th2) cytokines [interferon-gamma (IFN-gamma), interleukin-4 (IL-4), IL-10] in culture supernatants by enzyme-linked immunosorbent assay (ELISA). Furthermore, RNA isolated from ATV-stimulated RA-FLS pre- and post-ATV stimulation was analysed by microarray and quantitative reverse transcription polymerase chain reaction (RT-PCR). Flow cytometric analysis of T-cell subsets revealed no significant differences for CD4, CD8, CD69, and HLA-DR surface marker expression of PBMCs in RA patients and healthy controls after ATV stimulation. However, the proportion of IFN-gamma expressing CD4+ T cells and the IFN-gamma cytokine concentrations in culture supernatants were significantly reduced in T-cell cultures from RA patients. In ATV-stimulated FLS a significant downregulation of proinflammatory cytokine (IL-6) and chemokine (IL-8) expression was detected (p<0.001). Our study demonstrates a marked in vitro anti-inflammatory activity of ATV in RA including a systemic effect on a pathogenic CD4+ T-cell population (Th1) and a local effect on FLS. These findings may provide a scientific rationale for statins as add-on therapy in RA.

Blaschke S ，Viereck V ，Schwarz G ，Klinger HM ，Guerluek S ，Müller GA ... -  《-》

Analysis of Th1 and Th2 cytokines expressing CD4+ and CD8+ T cells in rheumatoid arthritis by flow cytometry.

A Th1/Th2 cytokine imbalance with a predominance of Th1 cytokines has been suggested to be of pathogenetic importance in rheumatoid arthritis (RA). To evaluate the role of Th1/Th2 cytokines in RA, we used intracellular cytokine flow cytometry to determine cytokine profiles of CD4+ and CD8+ T cells in 34 peripheral blood (PB) and 10 synovial fluid (SF) samples from patients with RA. Results were compared with 10 PB samples from healthy controls (HC) and 5 SF samples from patients with non-RA synovitis. After stimulating cells with PMA and ionomycin or alternatively with anti-CD3/CD28 in the presence of brefeldin A, intracellular levels of Th1 [interleukin 2 (IL-2), interferon-gamma (IFN-gamma)] and Th2 cytokines (IL-4, IL-5, IL-10, IL-13) were determined for CD3+CD8- (i.e., CD4+ Th1 and Th2 cells) and CD3+CD8+ (i.e., CD8+ Tc1 and Tc2 cells) T cells. The percentages of CD4+ and CD8+ Th1 and Th2 cytokines producing T cells (PB) were similar in patients with RA and healthy controls (HC), with a clear predominance of Th1 cytokines expressing, T cells. With regard to T cell subsets, IFN-gamma-producing T cells were significantly more frequently detected in the CD8+ subset [CD8+: median 45.1% (RA; p < 0.001), 38.2% (HC; p = 0.009) vs CD4+: 10.8%(RA), 17.0% (HC)]. Conversely, IL-2 was found in a higher percentage of CD4+ T cells [CD4+: median 33.4% (RA), 17.9% (HC) vs CD8+: 23.6% (RA), 12.3% (HC)]. Patients not in disease remission tended to have more IFN-gamma-producing CD8+ and IL-2-producing CD4+ T cells than patients in remission [CD8+: median 45.9% (IFN-gamma) vs 23.0% (IFN-gamma); CD4+: median 34.1% (IL-2) vs 18.2% (IL-2)1. In all PB samples, the proportion of T cells producing the Th2 cytokines IL-4, IL-5, IL-10, and IL-13 did not exceed 2%. Cytokine profiles did not differ between patients receiving immunosuppressive treatment and patients treated only with nonsteroidal antiinflammatory drugs. In comparison to PB, RA SF analysis revealed a significant increase in the percentage of IFN-gamma-producing CD4+ (p < 0.001) and CD8+ T cells (p < 0.001). In addition, the percentage of IL-10-producing CD4+ (p < 0.001) as well as CD8+ T cells (p = 0.001) was significantly elevated in SF. However, production of the other Th2 cytokines (IL-4, IL-5, IL-13) was similar in SF and PB. These data indicate similar cytokine profiles of T cells in PB of RA patients and healthy controls, with a strong predominance of Th1 cytokines producing T cells in the CD4+ and CD8+ T cell subset of both groups. PB cytokine profiles did not significantly differ in patients with active and non-active disease or between patients receiving and those not receiving immunosuppressive medication. In SF, the proportion of Th1 and Tcl cells was significantly elevated compared to PB, emphasizing the local importance of these cells for inflammation. CD8+ T cells (Tc1 cells) mainly contributed to the production of IFN-gamma, indicating an underestimated role of this cell subset for local cytokine production. The upregulation of IL-10-producing Th2 and Tc2 cells in SF may reflect an insufficient effort to down-regulate chronic inflammation in the joint. Modifying this cytokine imbalance in the joints may be a promising therapeutic approach in RA.

Berner B ，Akça D ，Jung T ，Muller GA ，Reuss-Borst MA ... -  《JOURNAL OF RHEUMATOLOGY》

Proinflammatory role of fractalkine (CX3CL1) in rheumatoid arthritis.

Fractalkine (CX3CL1) represents the sole member of the so-called CX3C chemokines. In rheumatoid arthritis (RA), functional studies suggest a role for this chemokine in monocyte chemotaxis and angiogenesis in the rheumatoid synovium. We analyzed the expression of fractalkine within different T cell subsets of the peripheral blood and expression of its receptor CX3CR1 within the rheumatoid synovium to further characterize its pathogenic role in RA. Peripheral blood mononuclear cells (PBMC) were isolated from 17 patients with RA and analyzed by flow cytometry in comparison to healthy blood donors. To identify the T helper cell cytokine profile of fractalkine-expressing cells, flow cytometric analysis of PBMC was performed after stimulation with PMA and ionomycin. Expression of fractalkine and its receptor was characterized in RA synovium by immunohistochemistry and laser capture microdissection microscopy. Flow cytometric analysis of fractalkine-expressing T cell subsets revealed a low proportion of fractalkine-expressing CD4+ and CD8+ T cells in both RA patients and controls. In addition, fractalkine was predominantly expressed in CD4+ T cells with a Th1-type cytokine expression profile. In RA synovium, fractalkine was detected in synovial macrophages, dendritic cells, endothelial cells, and a small proportion of T cells. The fractalkine receptor CX3CR1 was found in synovial macrophages, dendritic cells, and T cells as well as in synovial fibroblasts. Fractalkine stimulation of cultured synovial fibroblasts resulted in a marked upregulation of matrix metalloproteinase-2 (MMP-2) production. The results suggest that fractalkine may represent a Th1-type chemokine. Upregulation of MMP-2 production in synovial fibroblasts upon fractalkine stimulation in vitro supports the hypothesis of a proinflammatory role of this chemokine in RA.

Blaschke S ，Koziolek M ，Schwarz A ，Benöhr P ，Middel P ，Schwarz G ，Hummel KM ，Müller GA ... -  《JOURNAL OF RHEUMATOLOGY》

Reduced expression of the regulatory CD4+ T cell subset is related to Th1/Th2 balance and disease severity in rheumatoid arthritis.

Yudoh K ，Matsuno H ，Nakazawa F ，Yonezawa T ，Kimura T ... -  《ARTHRITIS AND RHEUMATISM》

Expression of activation-induced, T cell-derived, and chemokine-related cytokine/lymphotactin and its functional role in rheumatoid arthritis.

To evaluate the possible role of activation-induced, T cell-derived, and chemokine-related cytokine (ATAC)/lymphotactin (Lptn) in the pathogenesis of rheumatoid arthritis (RA). ATAC/Lptn levels in serum and synovial fluid samples were measured by sandwich enzyme-linked immunosorbent assay. Expression of messenger RNA for ATAC/Lptn in synovial tissues was analyzed by reverse transcription-polymerase chain reaction (PCR) and by in situ hybridization, and was quantitated by real-time PCR. The phenotype of peripheral blood mononuclear cells (PBMCs) expressing ATAC/Lptn was analyzed by intracellular cytokine staining and flow cytometry. Levels of ATAC/Lptn were similar in sera and synovial fluids from RA patients (n = 20) and osteoarthritis controls (n = 15). In phorbol myristate acetate/ionomycin-stimulated PBMCs, ATAC/Lptn expression was detected in CD8+ T cells and in a significantly increased proportion of CD4+,CD28- T cells from RA patients as compared with healthy controls. In synovial tissues, ATAC/Lptn was predominantly localized in CD3+ T cells in the sublining layer. Lymphocytes, synovial macrophages, and, unexpectedly, fibroblast-like synoviocytes (FLS) were identified as major target cells for ATAC/Lptn in RA synovium, as determined by analysis of the ATAC/Lptn receptor XCR1. In vitro, ATAC/Lptn stimulation of FLS resulted in a marked down-regulation of matrix metalloproteinase 2 production. These data indicate that in RA synovium, ATAC/Lptn is mainly produced by T cells. Considering its function as a lymphocyte-specific chemoattractant, ATAC/Lptn might be a key modulator for T cell trafficking in the pathogenesis of RA. In addition, functional studies suggest that ATAC/Lptn may exert additional immunomodulatory effects in RA.

Blaschke S ，Middel P ，Dorner BG ，Blaschke V ，Hummel KM ，Kroczek RA ，Reich K ，Benoehr P ，Koziolek M ，Müller GA ... -  《ARTHRITIS AND RHEUMATISM》