Yusuke Miwa

Neutrophil-derived cytokines: potential therapeutic targets in inflammation.

Polymorphonuclear neutrophils (PMNs) are usually thought of as the leukocyte population involved in acute inflammatory responses, acting as a first line of defense against invading microorganisms. These terminally differentiated cells are generally not thought of as an important source of de novo synthesis of polypeptide mediators. Recent progress has shown, however, that PMNs are able to synthesize cytokines in response to a variety of inflammatory stimuli and during certain pathological conditions. The expression profiles of PMN-derived cytokines are similar with those of monocytes/macrophages, major professional phagocytes. Like monocytes, PMNs are able to secrete proinflammatory cytokines [e.g., tumor necrosis factor (TNF)-alpha and interleukin (IL)-1beta], both CC and CXC chemokines [e.g., IL-8, interferon-inducible protein 10 (IP-10) and macrophage inflammatory protein (MIP)-1alpha], and angiogenic factors [e.g., vascular endothelial growth factor (VEGF)]. The secretion of cytokines by activated PMNs is regulated by immunoregulatory cytokines such as interferon (IFN)-gamma, IL-4, IL-10 and IL-13. In addition to acute inflammatory responses, PMNs and PMN-derived cytokines appear to be involved in the pathogenesis of such chronic inflammatory disorders as rheumatoid arthritis, inflammatory bowel diseases and mycobacterial infections. Conceivably, these findings place PMNs at a pivotal position where they regulate and orchestrate not only acute inflammatory responses but also chronic inflammation and immune regulation. As such, inhibition of PMN-derived cytokines is viewed as a potentially useful strategy for therapeutic immunointervention.

Biphasic regulation of the development of murine type ii collagen-induced arthritis by interleukin-12 : Possible involvement of endogenous interleukin-10 and tumor necrosis factor α

OBJECTIVE To examine the dose-specific effects of interleukin-12 (IL-12) on the evolution of murine type II collagen-induced arthritis (CIA). METHODS From day 24 through day 33 following primary immunization, mice received daily intraperitoneal injections of murine recombinant IL-12. Measurements of anticollagen IgG, cytokines, and corticosterone were performed using enzyme-linked immunosorbent assay and radioimmunoassay. RESULTS CIA mice injected with a low dose of IL-12 (5 ng/day) exhibited accelerated onset and increased severity of arthritis. In contrast, administration of a high dose of IL-12 (500 ng/day) attenuated arthritic inflammation. The low dose of IL-12 induced tumor necrosis factor alpha (TNFalpha) production, whereas the high dose induced production of both IL-10 and corticosterone and suppression of anticollagen antibody levels. Administration of neutralizing anti-TNFalpha and anti-IL-10 antibodies reversed the dose-specific effects of IL-12. CONCLUSION IL-12 is an important immunomodulator during the pathogenesis of CIA. It appears to act by regulating humoral and cellular immune responses, as well as by mediating the expression of immunoregulatory cytokines and glucocorticoids.

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.

Anti-TIF1-γ antibody and cancer-associated myositis A clinicohistopathologic study

Objective:We aimed to analyze the clinical and histopathologic features of cancer-associated myositis (CAM) in relation to anti–transcriptional intermediary factor 1 &ggr; antibody (anti-TIF1-&ggr;-Ab), a marker of cancer association. Methods:We retrospectively studied 349 patients with idiopathic inflammatory myopathies (IIMs), including 284 patients with pretreatment biopsy samples available. For the classification of IIMs, the European Neuromuscular Center criteria were applied. Patients with CAM with (anti-TIF1-&ggr;-Ab[+] CAM) and without anti-TIF1-&ggr;-Ab (anti-TIF1-&ggr;-Ab[−] CAM) were compared with patients with IIM without cancers within and beyond 3 years of myositis diagnosis. Results:Cancer was detected in 75 patients, of whom 36 (48%) were positive for anti-TIF1-&ggr;-Ab. In anti-TIF1-&ggr;-Ab(+) patients with CAM, cancers were detected within 1 year of myositis diagnosis in 35 (97%) and before 1 year of myositis diagnosis in 1. All the anti-TIF1-&ggr;-Ab(+) patients with CAM satisfied the dermatomyositis (DM) criteria, including 2 possible DM sine dermatitis cases, and were characterized histologically by the presence of perifascicular atrophy, vacuolated fibers (VFs), and dense C5b-9 deposits on capillaries (dC5b-9). In contrast, 39 anti-TIF1-&ggr;-Ab(−) patients with CAM were classified into various subgroups, and characterized by a higher frequency of necrotizing autoimmune myopathy (NAM). Notably, all 7 patients with CAM classified into the NAM subgroup were anti-TIF1-&ggr;-Ab(−) and exhibited no dC5b-9 or VFs. Conclusions:CAM includes clinicohistopathologically heterogeneous disease entities. Among CAM entities, anti-TIF1-&ggr;-Ab(+) CAM has characteristically shown a close temporal association with cancer detection and the histopathologic findings of dC5b-9 and VFs, and CAM with NAM is a subset of anti-TIF1-&ggr;-Ab(−) CAM.

Tacrolimus-induced pulmonary injury in rheumatoid arthritis patients.

BACKGROUND Tacrolimus (TAC) was approved in Japan in 2005 for rheumatoid arthritis (RA) patients having inadequate response to other disease-modifying anti-rheumatic drugs. As of May 2007, spontaneous reports identified twenty-seven cases of exacerbation or new development of interstitial pneumonia among RA patients given TAC in Japan. OBJECTIVE To describe the clinical and radiological characteristics of TAC-induced pulmonary injury (TIPI). PATIENTS AND METHODS Eleven RA patients diagnosed with de novo pulmonary injury or exacerbation of IP during treatment with TAC were identified. Clinical, radiological, and laboratory data of ten of these cases were retrospectively analyzed. RESULTS Baseline data for the ten patients were a mean age of 69.7 years; gender, 70% female; mean RA disease duration, 9.1 years; and pulmonary comorbidities, 90%. Six cases were classified as presumptive TAC-induced pulmonary injury (TIPI) and four as probable TIPI. Among the six presumptive cases, TIPI developed at an average of 84 days after initiation of treatment (n = 5) or four days after reinstitution of TAC (n = 1). Five cases were an exacerbation of pre-existing interstitial pneumonia and one was a de novo pulmonary injury. Radiological patterns of thoracic computed tomography (CT) scans of patients in the presumptive TIPI cases were hypersensitivity pneumonia like-pattern (n = 3), ground-glass opacity (n = 2), and organizing pneumonia-pattern (n = 1). All patients with presumptive TIPI were treated with high dosage glucocorticosteroids and one received concomitant immunosuppressants. Two of the six presumptive TIPI patients died. CONCLUSION Rheumatologists should be aware of this rare but potentially life-threatening adverse event in RA patients receiving TAC.

Tacrolimus-induced lung injury in a rheumatoid arthritis patient with interstitial pneumonitis

A 74-year-old woman was experiencing rheumatoid arthritis complicated with interstitial pneumonitis (IP), and tacrolimus treatment was started. She presented with dyspnea. Chest X-ray and computed tomography (CT) showed ground-glass opacity and IP. Although tacrolimus was stopped, she died of respiratory failure. At autopsy, both the upper and lower lung fields showed usual IP and the organizing stage of diffuse alveolar damage. The former is common, but the latter is uncommon, suggesting tacrolimus may cause severe alveolar damage.

Interaction of monocytes with vascular endothelial cells synergistically induces interferon γ-inducible protein 10 expression through activation of specific cell surface molecules and cytokines

To further understand the regulatory mechanisms involved in the process of angiogenesis, the present study was designed to determine the expression and regulation of interferon gamma-inducible protein 10 (IP-10) in peripheral blood monocytes and human umbilical vein endothelial cells (HUVECs). We found that the interaction of monocytes with HUVECs resulted in synergistic increases in IP-10 expression and secretion, which consequently inhibited endothelial tube formation in vitro. Induction of IP-10 was mediated via specific cell surface molecules, as indicated by the finding that IP-10 secretion was significantly inhibited by anti-CD40 ligand antibody, and to a lesser extent by anti-CD40 antibody. Furthermore, we examined the effects of soluble mediators, such as inflammatory and immune cytokines on IP-10 secretion. Addition of interleukin (IL)-1, as well as interferon gamma, induced a marked augmentation of IP-10 secretion by unstimulated monocytes, unstimulated HUVECs, and co-cultures of the two cell types. In contrast, IL-10, recognized as an anti-inflammatory cytokine, significantly inhibited IP-10 secretion by co-cultures. Our results suggest that the interaction of monocytes with endothelial cells results in synergistic increases in IP-10 expression and secretion, which contribute to the regulation of angiogenesis and initiation of inflammatory vascular diseases.

Synergistic induction of CX3CL1 by interleukin-1β and interferon-γ in human lung fibroblasts: involvement of signal transducer and activator of transcription 1 signaling pathways

CX3CL1 (fractalkine), a membrane-bound chemokine that induces both the adhesion and the migration of leukocytes, is involved in the recruitment of cells into tissues undergoing inflammatory responses. To explore the regulation of CX3CL1 in pulmonary inflammation and fibrosis, CX3CL1 expression in lung fibroblasts was examined. Normal human fibroblasts were obtained from Promocell (Lonza Walkersville Inc, Md) and were incubated in the presence or absence of various inflammatory stimuli. Culture supernatants were collected, and the soluble CX3CL1 levels were determined with an enzyme-linked immunosorbent assay. The expression of CX3CL1 mRNA transcripts in lung fibroblasts was assessed using quantitative TaqMan real-time polymerase chain reaction. Interleukin (IL)-1β or interferon (IFN)-γ individually induced negligible soluble CX3CL1 secretion by human lung fibroblasts after 24 h. However, the combination of IL-1β and IFN-γ induced dramatic increases in both soluble CX3CL1 protein and mRNA transcripts in a dose- and time-dependent manner. Synergistic up-regulation of cell-associated CX3CL1 protein also was observed after treatment with IL-1β and IFN-γ. The secretion and expression of lung fibroblast-derived CX3CL1 were markedly reduced by specific inhibitors of the STAT-1 transcription factor. These findings suggest that lung fibroblasts are an important cellular source of CX3CL1 and may play a role in pulmonary inflammation and fibrosis.

Correlation of serum CX3CL1 level with disease activity in adult-onset Still's disease and significant involvement in hemophagocytic syndrome

To investigate the characteristics of patients with adult-onset Stills disease (AOSD), serum cytokines and chemokines were measured to examine their associations with systemic manifestations of AOSD, especially hemophagocytic syndrome (HPS). Nineteen patients diagnosed with AOSD were enrolled. Serial serum samples were obtained from patients with AOSD in both active and inactive stages and controls. The concentrations of cytokines and chemokines, including IL-18, soluble IL-2 receptor (sIL-2R), CX3CL1, CXCL8, CXCL10, CCL2, and CCL3, were determined using enzyme-linked immunosorbent assay. Multivariate analysis was used to evaluate the correlations among serum chemokine levels, disease activity, and the clinical features of AOSD. Significantly higher serum levels of all cytokines and chemokines were observed in patients with active, untreated AOSD than in controls. The level of CX3CL1, but not other chemokines, was elevated in AOSD patients and was positively correlated with clinical activity and the levels of CRP, ferritin, IL-18, and sIL-2R. Among the 19 patients with AOSD, four patients also had HPS. Serum CX3CL1 and ferritin were significantly higher in AOSD patients with HPS than in those without HPS. The serum CX3CL1 level may be used as a clinical marker to assess the disease activity of AOSD, and high serum CX3CL1 and ferritin in patients with AOSD reflected the presence of HPS. The association between the chemokine profile and distinct clinical manifestations or various patterns of disease progression indicates that the pathogenesis of AOSD is heterogeneous.

Elevated serum levels of macrophage migration inhibitory factor and their significant correlation with rheumatoid vasculitis disease activity

Macrophage migration inhibitory factor (MIF) is recognized to be an important mediator in several inflammatory disorders, including rheumatoid arthritis (RA) and vasculitis. To evaluate the role of MIF in rheumatoid vasculitis (RV), we determined serum levels of MIF by enzyme-linked immunosorbent assay in RA patients with and without vasculitis and assessed their relationship to disease activity. Serum was obtained from 95 RA patients during active disease states [49 without vasculitis, 35 with extra-articular manifestations without histologically proven vasculitis, and 11 with histologically proven vasculitis] and from 22 healthy individuals. Vasculitis disease activity was assessed using the Birmingham Vasculitis Activity Score (BVAS). MIF levels were significantly higher in RA patients than in controls. Moreover, MIF levels were significantly higher in RA patients with vasculitis than in those without vasculitic complications. In all RA patients, a statistically significant positive correlation was observed between serum MIF levels and each of the following: serum levels of C-reactive protein, rheumatoid factor, and thrombomodulin; and the erythrocyte sedimentation rate. In the RV group, the elevation of MIF levels correlated with the BVAS. Our findings suggest that MIF may serve as an additional serologic inflammatory marker of disease activity in RV, and it may be implicated in the pathogenesis of RV.