Anti-tumor necrosis factor-alpha antibody treatment reduces serum CXCL16 levels in patients with rheumatoid arthritis

Differentially Expressed Genes of Natural Killer Cells Can Distinguish Rheumatoid Arthritis Patients from Healthy Controls

Rheumatoid arthritis (RA) is one of the most prevalent autoimmune diseases, while its molecular triggers are not fully understood. A few studies have shown that natural killer (NK) cells may play either a pathogenic or a protective role in RA. In this study, we sought to explore NK cell markers that could be plausibly used in evaluating the differences among healthy controls and RA patients. Publicly available transcriptome datasets from RA patients and healthy volunteers were analyzed, in order to identify differentially expressed genes (DEGs) between 1. different immune cells as compared to NK cells, and 2. NK cells of RA patients and healthy controls. The identified DEGs were validated using 16 healthy controls and 17 RA patients. Peripheral blood mononuclear cells (PBMCs) were separated by Ficoll density gradient method, while NK cells were isolated using RosetteSep technique. RNA was extracted and gene expression was assessed using RT-qPCR. All selected genes were differentially expressed in NK cells compared to PBMCs. CD56, CXCL16, PECAM-1, ITGB7, BTK, TLR10, and IL-1β were significantly upregulated, while CCL2, CCR4, RELA and IBTK were downregulated in the NK cells of RA patients when compared to healthy controls. Therefore, these NK specific genes might be used as promising biomarkers for RA diagnosis.

Heightened Levels of Antimicrobial Response Factors in Patients With Rheumatoid Arthritis

Rheumatoid arthritis (RA) is a chronic progressive autoimmune disease leading to considerable disability over time. The disease can be characterized by the presence of multiple autoantibodies in the serum and synovial fluid. Microbial dysbiosis is proposed to play a role in the pathogenesis of RA. Increased systemic bacterial exposure leads to elevated levels of antimicrobial response factors (ARFs) in the circulation. In the present study, we tested whether RA patients have increased levels of ARFs by analyzing the levels of multiple ARFs in serum from RA patients and healthy age and sex-matched controls. The levels of soluble CD14 (sCD14), lysozyme, and CXCL16 were significantly elevated in RA patients compared to healthy controls. Lipopolysaccharide binding protein (LBP) levels remained unchanged in RA patients compared to healthy controls. A positive correlation of LBP with rheumatoid factor (RF) was also found in RA subjects. Interestingly, the levels of anti-endotoxin core antibodies (EndoCAb) IgM, total IgM, EndoCAb IgA, and total IgA were significantly elevated in RA patients compared to healthy controls. No significant changes in the levels of EndoCAb IgG and total IgG were observed in RA patients compared to healthy controls. Furthermore, lysozyme and CXCL16 levels were positively correlated with disease severity among RA subjects. Increases in the levels of several ARFs and their correlations with clinical indices suggest systemic microbial exposure in the RA cohort. Modulation of microbial exposure may play an important role in disease pathogenesis in individuals with RA.

The role of CXC chemokine ligand 16 in physiological and pathological pregnancies

The survival and development of a semi-allogeneic fetus during pregnancy require the involvement of a series of cytokines and immune cells. Chemokines are a type of special cytokine those were originally described as having a role in leukocyte trafficking. CXC chemokine ligand (CXCL) 16 is a member of the chemokine family, and CXC chemokine receptor (CXCR) 6 is its sole receptor. Emerging evidence has shown that CXCL16/CXCR6 is expressed at the maternal-fetal interface, by cell types that include trophoblast cells, decidual stroma cells, and decidual immune cells (eg, monocytes, γδT cells, and natural killer T (NKT) cells). The regulation of expression of CXCL16 is quite complex, and this process involves a multitude of factors. CXCL16 exerts a critical role in the establishment of a successful pregnancy through a series of molecular interactions at the maternal-fetal interface. However, an abnormal expression of CXCL16 is associated with certain pathological states associated with pregnancy, including recurrent miscarriage, pre-eclampsia, and gestational diabetes mellitus (GDM). In the present review, the expression and pleiotropic roles of CXCL16 under conditions of physiological and pathological pregnancy are systematically discussed.

Increased plasma sCXCL16 levels may have a relationship with Th1/Th2 imbalance in primary immune thrombocytopenia

Primary immune thrombocytopenia (ITP) is a disease of autoimmunity in which there are Th1/Th2 imbalance and disordered cytokine profiles. CXC chemokine ligand 16 (CXCL16) was proved to implicate in some autoimmune diseases. Our research aimed to determine plasma soluble CXCL16 (sCXCL16) levels and its effects in ITP. We used ELISA to measure plasma sCXCL16, IFN-γ and IL-4 and flow cytometry to determine expression of CXCR6 on lymphocyte subsets. We used real-time PCR to detect the CXCL16 and CXCR6 mRNA expression. Additionally, plasma sCXCL16, CXCL16 and CXCR6 mRNA levels of 8 patients were monitored before and after treatment. We found that patients with active ITP had higher circulating sCXCL16 in plasma than healthy controls and patients in remission. Meanwhile, negative relationships between sCXCL16 and platelet count, IL-4 and positive relationships between sCXCL16 and IFN-γ, IFN-γ/IL-4 ratio were observed. Besides, expression of CXCR6 on lymphocyte subsets and mRNA levels of CXCL16 and CXCR6 were all increased in active ITP. Additionally, plasma sCXCL16 and IFN-γ levels and CXCR6 mRNA expression were down-regulated after effective treatment compared with those before treatment. Thus, increased plasma sCXCL16 might be implicated in the pathogenesis of ITP and have a relationship with Th1/Th2 imbalance.

Endothelial cells: From innocent bystanders to active participants in immune responses

The endothelium is crucially important for the delivery of oxygen and nutrients throughout the body under homeostatic conditions. However, it also contributes to pathology, including the initiation and perpetuation of inflammation. Understanding the function of endothelial cells (ECs) in inflammatory diseases and molecular mechanisms involved may lead to novel approaches to dampen inflammation and restore homeostasis. In this article, we discuss the various functions of ECs in inflammation with a focus on pathological angiogenesis, attraction of immune cells, antigen presentation, immunoregulatory properties and endothelial-to-mesenchymal transition (EndMT). We also review the current literature on approaches to target these processes in ECs to modulate immune responses and advance anti-inflammatory therapies.

CXCL16 upregulates RANKL expression in rheumatoid arthritis synovial fibroblasts through the JAK2/STAT3 and p38/MAPK signaling pathway

OBJECTIVE

To explore the influence of chemokine, CXCL16, on the expression of the receptor activator nuclear factor κB ligand (RANKL) in rheumatoid arthritis (RA) fibroblast-like synoviocytes (RA-FLS).

METHODS

The expression of CXCL16/CXCR6 and RANKL in RA or osteoarthritis (OA) patient synovia was examined by Western blot and immunohistochemistry. The serum concentration of CXCL16 and RANKL was measured by enzyme-linked immunosorbent assay (ELISA). RA-FLS were treated with recombinant CXCL16, and RANKL mRNA and protein were measured using PCR, Western blot and ELISA.

RESULTS

The synovial expression of CXCL16, CXCR6, and RANKL was higher in RA patients than in patients with OA. The serum CXCL16 and RANKL levels were higher in RA patients compared with OA patients and healthy controls. CXCL16 correlated with erythrocyte sedimentation rate, C reactive protein, disease activity, serum rheumatoid factor, and RANKL. RA-FLS treated with CXCL16 showed markedly increased expression of RANKL. When STAT3 or p38 activation was blocked by an inhibitor, CXCL16 failed to upregulate RANKL expression. In contrast, inhibiting the Akt or Erk pathway did not achieve the same effect.

CONCLUSIONS

CXCL16 upregulates RANKL expression in RA-FLS and these effects are mainly mediated by the JAK2/STAT3 and p38/MAPK signaling pathways.

The Interplay Between Monocytes/Macrophages and CD4(+) T Cell Subsets in Rheumatoid Arthritis

Rheumatoid arthritis (RA) is a chronic inflammatory disease characterized by inflammation of the synovial lining (synovitis). The inflammation in the RA joint is associated with and driven by immune cell infiltration, synovial hyperproliferation, and excessive production of proinflammatory mediators, such as tumor necrosis factor α (TNFα), interferon γ (IFNγ), interleukin (IL)-1β, IL-6, and IL-17, eventually resulting in damage to the cartilage and underlying bone. The RA joint harbors a wide range of immune cell types, including monocytes, macrophages, and CD4(+) T cells (both proinflammatory and regulatory). The interplay between CD14(+) myeloid cells and CD4(+) T cells can significantly influence CD4(+) T cell function, and conversely, effector vs. regulatory CD4(+) T cell subsets can exert profound effects on monocyte/macrophage function. In this review, we will discuss how the interplay between CD4(+) T cells and monocytes/macrophages may contribute to the immunopathology of RA.

Serum macrophage migration inhibitory factor levels are correlated with response to tocilizumab therapy in patients with rheumatoid arthritis

To examine the relationship between serum cytokine levels and response to tocilizumab in patients with RA. The disease status of 21 RA patients was assessed at baseline and after 12 weeks of tocilizumab treatment, using the clinical disease activity index (CDAI). Clinical response to tocilizumab was defined as an improvement of >50% from the baseline CDAI. Serum cytokine levels were quantified using double-ligand ELISA for TNF-α, IL-6, CCL2, CCL3, CXCL8, CXCL10, CX3CL1, and macrophage migration inhibitory factor (MIF). After 12 weeks of tocilizumab treatment, there was a significant overall reduction in RA disease activity (CDAI), from 22.4 ± 11.3 to 9.2 ± 6.6 (p < 0.0001), across the entire patient group. After 12 weeks of tocilizumab treatment, 14 patients achieved a >50% improvement (the responder group), but there were no significant responses in the other 7 patients (the non-responder group). The erythrocyte sedimentation rate levels, the positive % of anti-cyclic citrullinated protein antibody and patients (%) receiving methotrexate in combination with tocilizumab were significantly higher in the responder group than in the non-responder group. Although serum baseline levels of CCL2 and CXCL8 were higher in the responder group than in the non-responder group, there were no significant changes in these chemokine levels after treatment. The serum MIF levels, but not the levels of other cytokines, in the responder group were significantly decreased after tocilizumab treatment. Our results suggest that tocilizumab differentially regulates serum cytokine profiles in patients with RA, and MIF regulation in patients with active RA may be sensitive to anti-IL-6 therapy.

Serum interleukin 6 before and after therapy with tocilizumab is a principal biomarker in patients with rheumatoid arthritis

OBJECTIVE

Biologic treatments including the humanized anti-interleukin 6 (anti-IL-6) receptor antibody tocilizumab (TCZ) provide therapeutic options for patients with rheumatoid arthritis (RA). We investigated useful biomarkers to predict the responsiveness to TCZ by measurement of serum proinflammatory cytokine concentrations.

METHODS

Serum samples were collected from 61 patients with RA before biologic treatment and at 4 weeks after initial administration of either TCZ (n = 32) or infliximab (IFX; n = 29) and from 13 healthy serum donor controls. Disease Activity Score of 28 joints (DAS28) was determined at baseline and after treatment.

RESULTS

Although IL-1β, IL-2, IL-6, IL-17A, IL-17F, interferon-α, and tumor necrosis factor-α (TNF-α) were all increased in sera from patients with RA compared with controls, only the IL-6 level was significantly correlated with DAS28 before treatment. The IL-6 level before treatment was positively correlated with DAS28 after TCZ treatment, and was significantly lower in TCZ-responsive patients (as judged by a post-treatment DAS28 < 3.2) than in TCZ-resistant patients (post-treatment DAS28 ≥ 3.2). DAS28 after TCZ was significantly lower than after administration of IFX in patients with low pretreatment IL-6 (< 51.5 pg/ml, the mean baseline value of IL-6 in all RA patients), but not in those with high pretreatment IL-6. These results indicate that low serum IL-6 is associated with a favorable response to TCZ.

CONCLUSION

Although both TNF-α and IL-6 are major targets of therapeutic intervention in RA, baseline serum IL-6 but not baseline TNF-α level is a potential biomarker reflecting disease activity. Measurement of serum IL-6 in RA before treatment may be useful to estimate residual disease activity after TCZ treatment and to predict responsiveness to TCZ treatment.

Fractalkine stimulates cell growth and increases its expression via NF-κB pathway in RA-FLS

BACKGROUND

After the onset of rheumatoid arthritis (RA), fibroblast-like synoviocytes (RA-FLS) which are specialized types of fibroblasts, become tumor-like, keeping their ability to increase proliferation and invasion. The mechanism of their tumor-like growth is unclear. Fractalkine (FKN), also called CX3CL1, plays an important role in the proliferation of cells. FKN may stimulate the proliferation of RA-FLS and the by nuclear factor κB (NF-κB) pathway may be one of the steps in this process.

OBJECTIVE

To investigate whether FKN can stimulate cell growth and increase its expression in RA-FLS, and the relationship between the NF-κB pathway and the function of FKN.

METHODS

FLS were isolated from primary synovial tissue obtained from three patients with RA who had undergone total joint replacement surgery or synovectomy in the Third Hospital Affiliated to Sun Yat-sen University from February 2009 to January 2010. FKN was used in different concentrations to stimulate RA-FLS with or without NF-κB pathway blocker (PDTC), and to test the proliferation of FLS after 24 h by 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay. RA-FLS was treated with 100 ng/mL FKN or 100 μM PDTC for different periods, and messenger RNA (mRNA) expression of FKN and CX3CR1 in RA-FLS was detected by reverse transcription - polymerase chain reaction. We then tested the protein expression of NF-κBp65 in the cytoplasm and nucleus, respectively by Western blotting after treating the RA-FLS with 100 ng/mL FKN for different time periods.

RESULTS

FKN stimulated cell growth in RA-FLS at the concentration of 50 or 100 ng/mL (P = 0.005 and P = 0.022, respectively). NF-κB pathway blocker inhibited FKN, promoting proliferation of RA-FLS. RA-FLS could express FKN and CX3CR1 mRNA in vitro. FKN up-regulated FKN expression after 18-h treatment (P = 0.012). PDTC disturbed the expression of FKN mRNA after 16-18 h treatment (P = 0.001 and P < 0.001, respectively). After stimulation with FKN for 1 h, the expression of NF-κBp65 in cytoplasm began to decrease (P = 0.010), and the expression of NF-κBp65 in the nucleus began to increase after 2 h (P = 0.011).

CONCLUSION

These results suggest that FKN stimulates cells growth in RA-FLS and NF-κB pathway blocker inhibits FKN, promoting proliferation of RA-FLS. FKN induced activation of NF-κB activity. FKN up-regulates FKN mRNA expression in RA-FLS via the NF-κB pathway.

Overexpression of CXCL16 in lesional psoriatic skin

BACKGROUND

Psoriasis is characterized as an autoimmune disease resulting in an exaggerated innate immune response. The CXC-chemokine ligand 16 (CXCL16) is described to function as an adhesion molecule, a scavenger receptor or as a soluble molecule it acts as a chemoattractant. CXCL16 has been reported to be expressed in a variety of inflammatory diseases. However, no information has been reported in the literature about the expression of CXCL16 in psoriatic skin.

PURPOSE

The present study was designed to analyze the expression and localization of CXCL16 in human psoriatic skin tissues.

RESULTS

In normal skin, cytpoplasmic expression of CXCL16 was increased in keratinocytes of upper epidermal cell layers as compared to the lower epidermal cell layers. In lesional psoriatic skin, CXCL16 immunoreactivity was increased in the cytoplasm of keratinocytes of lower epidermal layer kerartinocytes as compared to the normal epidermis. Cytoplasmic CXCL16 expression was increased in the capillary endothelial cells of psoriatic dermis as compared to capillary endothelial cells of the normal dermis. Notably, almost all inflammatory cells in the dermis were negative for CXCL16.

MATERIALS AND METHODS

Ten paraffinized specimens of human lesional psoriatic skin and five paraffinized specimens of normal skin were studied using an immunohistochemical streptavidinperoxidase technique.

CONCLUSION

We here report for the first time alterations in the immunohistochemical staining pattern of CXCL16 in lesional psoriatic skin compared to the normal skin. These results suggest that CXCL16 may play a role in the pathogenesis of psoriasis.

Effect of posttranslational processing on the in vitro and in vivo activity of chemokines

The CXC and CC chemokine gene clusters provide an abundant number of chemotactic factors selectively binding to shared G protein-coupled receptors (GPCR). Hence, chemokines function in a complex network to mediate migration of the various leukocyte subsets, expressing specific GPCRs during the immune response. Further fine-tuning of the chemokine system is reached through specific posttranslational modifications of the mature proteins. Indeed, enzymatic processing of chemokines during an early phase of inflammation leads to activation of precursor molecules or cleavage into even more active or receptor specific chemokine isoforms. At a further stage, proteolytic processing leads to loss of GPCR signaling, thereby providing natural chemokine receptor antagonists. Finally, further NH(2)-terminal cleavage results in complete inactivation to dampen the inflammatory response. During inflammatory responses, the two chemokines which exist in a membrane-bound form may be released by proteases from the cellular surface. In addition to proteolytic processing, citrullination and glycosylation of chemokines is also important for their biological activity. In particular, citrullination of arginine residues seems to reduce the inflammatory activity of chemokines in vivo. This goes along with other positive and negative regulatory mechanisms for leukocyte migration, such as chemokine synergy and scavenging by decoy receptors.

Etanercept treatment reduces the serum levels of interleukin-15 and interferon-gamma inducible protein-10 in patients with rheumatoid arthritis

Tumor necrosis factor-alpha (TNF-alpha) has an essential role in the pathogenesis of rheumatoid arthritis (RA) and has been known to induce the production of several inflammatory molecules in vivo. To analyze in vivo the active mechanism of the TNF-alpha blocking agent, etanercept, the serum levels of the cytokine interleukin-15 (IL-15) and the chemokines growth-regulated protein-alpha (Gro-alpha), and interferon-gamma inducible protein-10 (IP-10) in RA patients were measured. Twenty-two patients with RA were administered etanercept once or twice a week for more than 6 months. The clinical and laboratory parameters were measured and serum levels of IL-15, Gro-alpha, and IP-10 were determined using enzyme-linked immunosorbent assay (ELISA) kits at the baseline and at 3 and 6 months after the initial treatment. Additionally, the production of IL-15 and IP-10 by cultured synovial cells stimulated with TNF-alpha from RA patients was determined by ELISA. A significant decrease in serum levels of IL-15 and IP-10 was observed at 3 and 6 months after initial treatment with etanercept, but not in those of Gro-alpha. TNF-alpha induced production of IP-10, but not IL-15 in cultured synovial cells from RA patients. This study demonstrated for the first time the reduction of IP-10 and IL-15 production in RA patients as active mechanisms of etanercept.

CXCL 9 and CXCL 10 as Sensitive markers of disease activity in patients with rheumatoid arthritis

OBJECTIVE

To assess whether serum levels of CC and CXC chemokines correlate with disease activity in patients with rheumatoid arthritis (RA), and to determine whether these effects predict clinical response.

METHODS

Serum levels of the chemokines CC (CCL2, CCL5) and CXC (CXCL8, CXCL9, CXCL10) were quantified at baseline and after 12 weeks of treatment with disease-modifying antirheumatic drugs or biologic agents in 28 patients using flow cytometry. Serum from 40 healthy individuals was collected for comparison at baseline. Response to treatment was classified according to the European League Against Rheumatism (EULAR) response criteria. Remission of disease was defined as a Disease Activity Score < 2.6.

RESULTS

The baseline serum concentrations of CC and CXC chemokines were significantly elevated in patients with active RA compared to healthy controls (p < 0.05) except for CCL2. Significant improvement in all disease activity measurements was observed after 12 weeks of treatment. Seventeen (60.7%) patients achieved good to moderate response based on the EULAR response criteria, and 5 (17.9%) patients achieved remission. The improvement in clinical activity in patients with RA was accompanied by a significant reduction in the serum concentration of CXCL9 and CXCL10 (p < 0.001). A significant reduction in the serum level of CXCL10 was also observed in the group that achieved EULAR response. Serum concentration of CCL5 remained significantly elevated in patients with RA (n = 5) who achieved remission compared to the healthy controls (p < 0.05).

CONCLUSION

Serum concentration of CXCL9 and CXCL10 may serve as sensitive biomarkers for disease activity in patients with RA.

CXCL16 in HIV infection - a link between inflammation and viral replication

BACKGROUND

While some chemokines are thought to be protective in HIV-infected individuals by their ability to block HIV entry into T cells and macrophages, chemokines could also have harmful effects in HIV infection through their ability to promote inflammation. Here, we examined the regulation and the effects of CXCL16, a newly discovered chemokine of the CXC family, in HIV-infected patients.

MATERIALS AND METHODS

We examined serum levels of CXCL16 in clinically well-defined subgroups of HIV-infected individuals both before (n = 62) and during HAART (n = 40) as well as in age- and sex-matched healthy controls (n = 30). We also examined the effects of CXCL16 on inflammatory and anti-inflammatory cytokines and HIV replication in peripheral blood mononuclear cells (PBMC).

RESULTS

Our main and novel findings were: (i) HIV-infected patients had significant raised CXCL16 levels according to disease severity and progression. (ii) During HAART, the immunological improvement was accompanied by a modest increase in CXCL16 level. (iii) While soluble CXCL16 promoted an anti-inflammatory response in PBMC from those on successful HAART, it induced an inflammatory response and enhanced HIV replication in PBMC from those with high viral load irrespectively of ongoing HAART. (iv) Recombinant HIV-tat protein significantly increased CXCL16 release in THP-1 macrophages.

CONCLUSIONS

Our findings suggest a complex interaction between CXCL16 and HIV, promoting both inflammatory and anti-inflammatory effects as well as HIV replication, partly dependent on accompanying HIV replication.

Immunosuppressive effects of mesenchymal stem cells in collagen-induced mouse arthritis

OBJECTIVE

The objective of this study was to investigate the efficacy of mesenchymal stem cell (MSC) in the treatment of arthritis.

METHODS

Mesenchymal stem cells were injected intravenously into mice with collagen-induced arthritis (CIA). Arthritic indexes were evaluated, and the levels of the pro- and anti-inflammatory cytokines interleukin-10 (IL-10), gamma interferon (IFN-gamma)-inducible protein 10 (IP-10), chemokine (C-X-C motif) receptor 3 (CXCR3), interleukin-17A (IL-17A), and tumor necrosis factor alpha (TNF-alpha) in serum or splenic cells were determined using real-time RT-PCR, Western blotting, and enzyme-linked immunosorbent assay (ELISA). The proliferation of dendritic cell line D2SC cells was determined using (3)H-TdR incorporation assay.

RESULTS

Upon injection of MSCs, overall arthritis symptoms were significantly improved in the CIA mouse models as indicated by the paw edema. Consistent with this observation, serum levels of pro-inflammatory cytokine TNF-alpha and inflammatory cell infiltration decreased significantly 12 days after MSC injection, while the expression of anti-inflammatory cytokines IL-10, IP-10, and CXCR3 was increased in splenocytes. In addition, we provided evidence that MSCs may directly promote the proliferation of D2SC cells and the expression of IP-10 in D2SC cells in vitro.

CONCLUSION

Mesenchymal stem cells significantly enhance the efficacy of collagen-induced arthritis treatment, likely through the modulation of the expression of various cytokines.

E-selectin, interleukin 18, serum amyloid a, and matrix metalloproteinase 9 are associated with clinical response to golimumab plus methotrexate in patients with active rheumatoid arthritis despite methotrexate therapy

OBJECTIVE

To assess the effect of golimumab (human monoclonal antibody to tumor necrosis factor-alpha) plus methotrexate (MTX) on selected inflammatory biomarkers, and to determine if these effects predict clinical response in rheumatoid arthritis (RA).

METHODS

Sera from adults with active RA despite MTX therapy, who received subcutaneous injections of placebo + MTX (MTX alone, n = 34) or golimumab 50 or 100 mg every 2 or 4 weeks + MTX (n = 137), were analyzed for levels of C-reactive protein (CRP), serum amyloid A (SAA), interleukin 18 (IL-18), E-selectin, matrix metalloproteinase 9 (MMP-9), and tissue inhibitor of matrix metalloproteinase 1 (TIMP-1).

RESULTS

Golimumab + MTX treatment significantly decreased serum CRP, SAA, IL-18, E-selectin, TIMP-1, and MMP-9 levels (median percent changes of -4.1% to -74.3% across treatment groups) versus MTX alone (-5.8% to 9.7%) when first measured at Week 4; decreases were sustained through Week 16. Larger magnitudes of decrease in all biomarkers were observed for clinical responders versus nonresponders. For golimumab + MTX, regression analyses including all biomarkers and select clinical measures showed that reductions in levels of several markers (SAA, E-selectin, MMP-9) as early as Week 4 correlated significantly with improvement in swollen joint count (SJC) at Week 16, as did reductions in E-selectin with improvement in tender joint count at Week 16. After accounting for the biomarkers, however, treatment group was no longer significant for SJC.

CONCLUSION

Significant decreases in several inflammatory biomarkers were associated with golimumab + MTX therapy. Decreases in serum levels of SAA, E-selectin, and MMP-9 at Week 4 may be useful in predicting clinical response at Week 16.

Correlation of CX3CL1 and CX3CR1 Levels with Response to Infliximab Therapy in Patients with Rheumatoid Arthritis

Objective.

To examine the relation between serum chemokine levels and patient responsiveness to infliximab, and the influence of infliximab administration on serum chemokine levels.

Methods.

Serum levels of the chemokines CX3CL1, CXCL8, CCL3, and CXCL10 were quantified prior to (at baseline) and after 30 weeks of treatment with infliximab in 20 patients using enzyme-linked immunosorbent assays. Disease status was assessed using the Disease Activity Score (DAS28). The response to infliximab was classified according to the European League Against Rheumatism (EULAR) response criteria.

Results.

By 30 weeks, infliximab produced a significant overall reduction in DAS28 among the 20 patients with RA, although only 12 achieved a good to moderate response based on EULAR response criteria. A significant reduction in CX3CL1 was seen in the responsive group, although infliximab treatment had no significant effect on the serum levels of the other 3 chemokines. Comparison of patients with lower (< 2000 pg/ml) and higher (≥ 2000 pg/ml) basal CX3CL1 levels revealed that DAS28, erythrocyte sedimentation rate, C-reactive protein, and CX3CL1 levels were all significantly diminished by infliximab in RA patients with lower basal CX3CL1 levels, but not in those with higher basal levels. In addition, cell-surface expression of CX3CR1 protein in peripheral blood CD8+CD3+ T cells and mRNA expression of CX3CR1 in lymphocytes were both significantly downregulated after infliximab treatment in the responsive group.

Conclusion.

Our results suggest that the CX3CL1-CX3CR1 system in patients with active RA may be sensitive to anti-tumor necrosis factor-α therapy, and confirm that CX3CL1 plays a crucial role in the pathogenesis of RA.

Common inflammatory mediators orchestrate pathophysiological processes in rheumatoid arthritis and atherosclerosis

RA is characterized by a systemic inflammatory state, in which immune cells and soluble mediators play a crucial role. These inflammatory processes resemble those in other chronic inflammatory diseases, such as atherosclerosis. The chronic systemic inflammation in RA can be considered as an independent risk factor for the development of atherosclerosis, and represents an important field to investigate the reasons of the increase of acute cardiovascular events in RA. In the present review, we focused on several mediators of autoimmunity, inflammation and endothelial dysfunction, which can be considered the most promising targets to prevent atherogenesis in RA. Among several mediators, the pro-inflammatory cytokine TNF-alpha has been shown as a crucial factor to induce atherosclerosis in RA patients.

Anti-TNF antibodies: lessons from the past, roadmap for the future

Tumor necrosis factor alpha (TNF) is an important cell-signaling component of the immune system. Since its discovery over 20 years ago, much has been learned about its functions under normal and disease conditions. Nonclinical studies suggested a role for TNF in chronic immune-mediated inflammatory diseases, such as rheumatoid arthritis, Crohn's disease, and psoriasis, and therefore neutralizing monoclonal antibodies specific to human TNF were developed for clinical evaluation. Treatment with anti-TNF monoclonal antibodies (infliximab, adalimumab, and certolizumab pegol) has been shown to provide substantial benefit to patients through reductions in both localized and systemic expression of markers associated with inflammation. In addition, there are beneficial effects of anti-TNF treatment on markers of bone and cartilage turnover. Further exploration of changes in these markers and their correlation with clinical measures of efficacy will be required to allow accurate prediction of those patients most in need of these treatments. Both the clinical and commercial experience with these anti-TNF antibodies provide a wealth of information regarding their pharmacological effects in humans.