Introduction Deposition of B cells in the rheumatoid arthritis (RA) synovium has been reported and it has been thought that these cells might contribute to the pathogenesis of RA by antigen demonstration autoantibody production and/or inflammatory cytokine production. blood B cells of healthy donors and subjects with RA expressed CC chemokine receptor Homoharringtonine (CCR)5 and CXCR3 and most B cells expressed CCR6 CCR7 CXCR4 and CXCR5. CCR5 expression was more Homoharringtonine frequent on CD27+ than CD27- peripheral blood B cells of healthy donors and RA. Synovial B cells more frequently expressed CCR5 but less often expressed CCR6 CCR7 and CXCR5 compared to peripheral blood in RA. Further functional analyses were performed on peripheral blood B cells from healthy donors. Migration of peripheral blood B cells especially CD27+ B cells was enhanced by CC chemokine ligand (CCL)20 CCL19 CCL21 and CXCL12. All four chemokines alone induced B cell proliferation; with CCL21 being the most effective. CCL21 also enhanced the proliferation of anti-immunoglobulin (Ig)M-stimulated B cells and blockade of CCR7 inhibited this effect. CCL20 CCL21 and CXCL12 enhanced TNF production by anti-IgM mAb-stimulated B cells. Finally stimulation with CXCL12 but not CCL20 CCL19 and CCL21 enhanced inducible costimulator-ligand (ICOSL) expression by peripheral blood B cells of healthy donors and RA but did not increase B cell-activating factor receptor or transmembrane activator and CAML-interactor. Conclusions The data suggest that CCR5 CCR6 CCR7 CXCR3 CXCR4 and CXCR5 may be important for the B cell migration into the synovium of RA patients and in addition their regional proliferation cytokine creation and ICOSL manifestation in the synovium. Intro Rheumatoid arthritis (RA) is characterized by chronic inflammation of multiple Homoharringtonine joints. As B cell depletion by treatment with rituximab an anti-CD20 monoclonal antibody (mAb) is beneficial for RA patients [1 2 B cells are considered to play important roles in the pathogenesis of RA. In this regard the synovial tissue of RA patients shows abundant accumulation of inflammatory cells including T cells macrophages dendritic cells and B cells [3-6]. Synovial B cells could present antigens to T cells. Importantly rheumatoid factor-expressing B cells that are found within the synovium [7] can present any antigen in the context of an immune complex and thereby trigger T cells specific for a variety of foreign antigens [8]. Notably the severity of RA correlates Rabbit Polyclonal to PDCD4 (phospho-Ser67). with levels of rheumatoid factor [9]. Furthermore activated B cells produce inflammatory cytokines such as TNF [10]. Therefore synovial B cells could contribute to the pathogenesis of RA by antigen presentation autoantibody production and inflammatory cytokine production. One of the mechanisms for accumulation of B cells in synovial tissues relates to the interaction with chemokines produced in the RA synovium and chemokine receptors expressed by the B cells [6]. Chemokines are classified into C CC CXC and CX3C subclasses based on the conserved cysteine motifs [11] and are involved in cellular migration activation of adhesion molecules cellular proliferation cytokine production and regulation of apoptosis [12 13 Chemokines contribute to homeostatic migration as well as entry into acute and chronic inflammatory sites. Expression of chemokines and chemokine receptors in the RA synovial tissue has been extensively analyzed and chemokines are thought to be potential therapeutic targets [14 15 However the role of chemokines specifically on B cells in RA has not been completely delineated. In this study we examined chemokine receptor expression by peripheral blood in both regular donors Homoharringtonine and topics with RA and in addition synovial B cells from subjects with RA and determined the functional effects of chemokines on B cells. Materials and methods Samples Peripheral blood samples were obtained from healthy donors and subjects with RA after obtaining informed Homoharringtonine consent. RA was diagnosed according to the criteria of the American College of Rheumatology [16]. Synovial tissues were obtained at the time of total knee joint replacement from RA patients. Signed consent forms were obtained prior to the operation. The analysis protocol was approved beforehand from the Ethics Committee from the Tokyo Oral and Medical University. Chemokine receptor manifestation Peripheral bloodstream mononuclear.