Anti-cytokine therapy for rheumatoid arthritis

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

The aim of this study was to analyze the change of serum chemokins levels of CXCL16, CX3CL1/Fractalkine, and CXCL10/interferon-gamma inducible protein-10 (IP-10) with rheumatoid arthritis (RA), by infliximab treatment. The effects of infliximab treatment were studied in 23 patients with RA, over a period of 30 weeks. The serum levels of CXCL16, Fractalkine, and IP-10, were measured at the baseline, just before initial treatment, and at 14 and 30 weeks after the initial treatment, with infliximab by ELISA. The higher levels of serum CXCL16 in the RA patients before treatment with infliximab significantly decreased at 14 and 30 weeks after the initial treatment with infliximab, but the serum Fractalkine and IP-10 levels did not decrease significantly. Infliximab treatment significantly lowered the serum levels of CXCL16 in patients with RA. CXCL16 is one of the crucial chemokines regulated by infliximab treatment.

Rhinovirus replication in human macrophages induces NF-kappaB-dependent tumor necrosis factor alpha production

Rhinoviruses (RV) are the major cause of acute exacerbations of asthma and chronic obstructive pulmonary disease (COPD). Rhinoviruses have been shown to activate macrophages, but rhinovirus replication in macrophages has not been reported. Tumor necrosis factor alpha (TNF-alpha) is implicated in the pathogenesis of acute exacerbations, but its cellular source and mechanisms of induction by virus infection are unclear. We hypothesized that rhinovirus replication in human macrophages causes activation and nuclear translocation of NF-kappaB, leading to TNF-alpha production. Using macrophages derived from the human monocytic cell line THP-1 and from primary human monocytes, we demonstrated that rhinovirus replication was productive in THP-1 macrophages, leading to release of infectious virus into supernatants, but was limited in monocyte-derived macrophages, likely due to type I interferon production, which was robust in monocyte-derived but deficient in THP-1-derived macrophages. Similar to bronchial epithelial cells, only small numbers of cells supported complete virus replication. We demonstrated RV-induced activation of NF-kappaB and colocalization of p65/NF-kappaB nuclear translocation with virus replication in both macrophage types. The infection induced TNF-alpha release in a time- and dose-dependent, RV serotype- and receptor-independent manner and was largely (THP-1 derived) or completely (monocyte derived) dependent upon virus replication. Finally, we established the requirement for NF-kappaB but not p38 mitogen-activated protein kinase in induction of TNF-alpha. These data suggest RV infection of macrophages may be an important source of proinflammatory cytokines implicated in the pathogenesis of exacerbations of asthma and COPD. They also confirm inhibition of NF-kappaB as a promising target for development of new therapeutic intervention strategies.

Targeting lymphangiogenesis to prevent tumour metastasis

Recent studies involving animal models of cancer and clinicopathological analyses of human tumours suggest that the growth of lymphatic vessels (lymphangiogenesis) in or nearby tumours is associated with the metastatic spread of cancer. The best validated molecular signalling system for tumour lymphangiogenesis involves the secreted proteins vascular endothelial growth factor-C (VEGF-C) and VEGF-D that induce growth of lymphatic vessels via activation of VEGF receptor-3 (VEGFR-3) localised on the surface of lymphatic endothelial cells. In this review, we discuss the evidence supporting a role for this signalling system in the spread of cancer and potential approaches for blocking this system to prevent tumour metastasis.

CD64-Directed Immunotoxin Inhibits Arthritis in a Novel CD64 Transgenic Rat Model

Macrophages are known to play a key role during inflammation in rheumatoid arthritis (RA). Inflammatory macrophages have increased expression of CD64, the high-affinity receptor for IgG. Targeting this receptor through a CD64-directed immunotoxin, composed of an Ab against CD64 and Ricin A, results in effective killing of inflammatory macrophages. In this study, we show elevated levels of CD64 on synovial macrophages in both synovial lining and synovial fluid in RA patients. The CD64-directed immunotoxin efficiently eliminates activated synovial macrophages in vitro, while leaving quiescent, low CD64-expressing macrophages unaffected. To examine whether killing of CD64 macrophages results in therapeutic effects in vivo, we established an adjuvant arthritis (AA) model in newly generated human CD64 (hCD64) transgenic rats. We demonstrate that hCD64 regulation in this transgenic rat model is similar as in humans. After AA induction, treatment with CD64-directed immunotoxin results in significant inhibition of disease activity. There is a direct correlation between immunotoxin treatment and decreased macrophage numbers, followed by diminished inflammation and bone erosion in paws of these hCD64 transgenic rats. These data support synovial macrophages to play a crucial role in joint inflammation in AA in rats and in human RA. Selective elimination of inflammatory macrophages through a CD64-directed immunotoxin may provide a novel approach for treatment of RA.

The comparative study of Sprague-Dawley and Lewis rats in adjuvant-induced arthritis

The outbred Sprague-Dawley (SD) rats, similar to the inbred Lewis (LEW) rats, have been recently demonstrated to be highly susceptible to adjuvant-induced arthritis (AIA). We herein compared AIA in SD and LEW rats in terms of clinical, histological, radiological, and immuno-inflammatory features. The results showed that, following inoculation with a ground Mycobacterium tuberculosis (MT) suspension, SD and LEW rats manifested closely similar disease progression, with 100% incidence and similar severity. The development of arthritis was accompanied by significantly higher erythrocyte sedimentation rate (ESR) and C-reactive protein (CRP) levels than in control rats. Radiographic examination of the hind paws showed that both SD and LEW AIA rats manifested conspicuous soft tissue swelling, bone matrix resorption, periosteal new bone formation and bone erosion, while histopathological analysis of the synovial joints revealed marked cellular infiltration, angiogenesis, synovial hyperplasia, pannus formation, narrowing of joint space, and cartilage and bone destruction. Moreover, in relation to disease progression, serum tumor necrosis factor-alpha (TNF-alpha), interleukin-1beta (IL-1beta), and IL-6 levels were markedly overexpressed in both SD and LEW AIA versus control rats, and SD and LEW AIA rats exhibited divergent profiles for the expression of TNF-alpha and IL-1beta. Taken together, these results demonstrated that the SD rat AIA model shares several arthritic features with the comparable model in LEW rats. Hence, given the more favorable characteristics of SD rats than LEW rats (i.e., lower cost, wider availability, and heterogenic background), this SD rat AIA model is more cost effective and advantageous for screening and testing novel anti-arthritic agents.

Biologics in the treatment of transplant rejection and ischemia/reperfusion injury: new applications for TNFalpha inhibitors?

Tumor necrosis factor (TNF)-alpha inhibitors have proven efficacy in various autoimmune diseases such as Crohn disease, rheumatoid arthritis, psoriasis, and ankylosing spondylitis. Indeed, some TNFalpha inhibitors have already been approved for the management of the inflammatory manifestations associated with Crohn disease and rheumatoid arthritis. These agents are increasingly used for treatment of corticosteroid-resistant graft-versus-host disease after bone marrow transplantation, and case reports have documented their efficacy in treating corticosteroid- and muromonab-resistant rejection after intestinal transplantation. Thus, the potential role of TNFalpha inhibitors in transplantation of other vascularized solid organs is worthy of investigation. Experimental evidence indicates that TNFalpha plays a key role in mediating ischemia/reperfusion (IR) injury after liver, kidney, intestine, heart, lung, and pancreas transplantation. TNFalpha was also identified as a marker cytokine during organ rejection. Single-center studies evaluating the role of TNFalpha inhibitors in kidney transplantation have been initiated but the results are not yet available. TNFalpha is known to be a contributing factor in kidney allograft rejection, and may have value in predicting the onset of steroid-resistant acute rejection after liver transplantation. Experimental and preliminary clinical data have shown that circulating levels of TNFalpha are increased during cardiac graft rejection, and indicate that TNFalpha plays a role in the pathogenesis of acute cardiac allograft rejection. Anti-TNFalpha therapy was shown to prolong cardiac allograft survival when used alone or in combination with other drugs. TNFalpha genotype has been strongly associated with mortality in humans due to acute cell-mediated heart transplant rejection. In addition, there is evidence for a genetic predisposition toward acute rejection after kidney and simultaneous kidney-pancreas transplantation. TNFalpha inhibition has been used successfully as part of an induction therapy for pancreatic islet cell transplantation. Apart from IR injury and acute rejection after lung transplantation, TNFalpha was also found to be involved in the pathoimmunology of obliterative bronchiolitis. In conclusion, a substantial body of experimental evidence and preliminary clinical data suggest that TNFalpha inhibitors may play an important role in solid-organ transplantation, both in the amelioration of IR injury and in the treatment and prevention of acute rejection. Pharmacodynamic monitoring and pharmacogenetic screening may help to identify patients most likely to benefit from TNFalpha blockade. Randomized controlled trials in patients undergoing solid-organ transplantation are needed to further elucidate the clinical value of TNFalpha inhibition.

The shared epitope is a marker of severity associated with selection for, but not with response to, infliximab in a large rheumatoid arthritis population

OBJECTIVE

To determine whether joint destruction, indication for, and response to infliximab in rheumatoid arthritis are associated with the shared epitope (SE) or selected cytokine gene polymorphisms (interleukin (IL) 1B, IL1-RN, and tumour necrosis alpha).

METHODS

In a large rheumatoid arthritis population of 930 patients from the same area (Rhône-Alpes, France), patients with (n = 198) or without infliximab treatment (n = 732) were compared according to their genetic status. Clinical, biological, and radiological data were collected. Typing for SE status and cytokine polymorphisms was carried out using enzyme linked oligosorbent assay. Statistical analysis was by chi(2) testing and calculation of odds ratios (OR).

RESULTS

A dose relation was observed between the number of SE copies and joint damage in the whole rheumatoid population (OR, 1 v 0 SE copy = 2.38 (95% confidence interval, 1.77 to 3.19), p<0.001; OR 2 v 0 SE copy = 3.92 (2.65 to 5.80), p<0.001. The SE effect increased with disease duration but was not significant before two years. Selection for infliximab treatment (n = 198) was associated with increased disease activity, joint damage, and the presence of the SE with a dose effect. In all, 66.2% patients achieved an ACR20 improvement. No clinical or genetic factors were able to predict the clinical response to infliximab.

CONCLUSIONS

This post-marketing study in a large cohort of rheumatoid arthritis patients indicates a linkage between rheumatoid arthritis severity, selection for treatment with infliximab, and the presence and dose of the SE.

The effect of infliximab on bone metabolism markers in patients with rheumatoid arthritis

OBJECTIVE

The aim of this study was to evaluate urinary excretion of N-telopeptide of type I collagen (NTX) and deoxypyridinoline (DPD), markers of bone resorption, and serum bone alkaline phosphatase (BAP) level, a marker of bone formation and an early marker of osteoblast differentiation, in patients with rheumatoid arthritis (RA) treated with infliximab.

METHODS

Seventeen male and female patients (age 60.7+/-2.53 yr; mean disease duration 12.9+/-3.01 yr; Steinbrocker's class II-IV) with RA, diagnosed according to the criteria of the American College of Rheumatology (ACR), took part in the study between March 2003 and January 2005. None of the patients had a history of oestrogen replacement therapy. All patients were treated with infliximab combined with methotrexate. Infliximab was infused intravenously at 3 mg/kg at baseline, 2 and 6 weeks, then every 8 weeks. To evaluate disease activity, ESR, CRP, the numbers of swollen and tender joints, modified Stanford Health Assessment Questionnaire (mHAQ) score and ACR score were measured. Levels of NTX and DPD in urine and BAP in serum were measured in all patients.

RESULTS

ESR, CRP, the number of swollen joints and tender joints, and mHAQ score had decreased significantly 6 weeks after initial treatment and were still low 6 months after initial treatment. NTX levels had decreased significantly 6 weeks after the initial treatment and were still low 6 months after initial treatment. DPD levels had decreased 6 months after initial infusion. Mean serum BAP level did not differ significantly among the three time points. NTX levels were statistically corresponding with the number of swollen joints and mHAQ scores. DPD levels were statistically lower corresponding with ESR.

CONCLUSION

Infliximab therapy may inhibit generalized bone loss in patients with RA. NTX is a more sensitive marker than DPD.

Protein Expression of TNF-α in Psoriatic Skin Is Regulated at a Posttranscriptional Level by MAPK-Activated Protein Kinase 2

Alterations in specific signal transduction pathways may explain the increased expression of proinflammatory cytokines seen in inflammatory diseases such as psoriasis. We reveal increased TNF-alpha protein expression, but similar TNF-alpha mRNA levels, in lesional compared with nonlesional psoriatic skin, demonstrating for the first time that TNF-alpha expression in lesional psoriatic skin is regulated posttranscriptionally. Increased levels of activated MAPK-activated protein kinase 2 (MK2) together with increased MK2 kinase activity were found in lesional compared with nonlesional psoriatic skin. Immunohistochemical analysis showed that activated MK2 was located in the basal layers of the psoriatic epidermis, whereas no positive staining was seen in nonlesional psoriatic skin. In vitro experiments demonstrated that both anisomycin and IL-1beta caused a significant activation of p38 MAPK and MK2 in cultured normal human keratinocytes. In addition, TNF-alpha protein levels were significantly up-regulated in keratinocytes stimulated with anisomycin or IL-1beta. This increase in TNF-alpha protein expression was completely blocked by the p38 inhibitor, SB202190. Transfection of cultured keratinocytes with MK2-specific small interfering RNA led to a significant decrease in MK2 expression and a subsequent significant reduction in the protein expression of the proinflammatory cytokines TNF-alpha, IL-6, and IL-8, whereas no change in the expression of the anti-inflammatory cytokine IL-10 was seen. This is the first time that MK2 expression and activity have been investigated in an inflammatory disease such as psoriasis. The results strongly suggest that increased activation of MK2 is responsible for the elevated and posttranscriptionally regulated TNF-alpha protein expression in psoriatic skin, making MK2 a potential target in the treatment of psoriasis.

Effect of inflammation on lacrimal gland function

The lacrimal gland is the main contributor to the aqueous layer of the tear film. It secretes proteins, electrolytes and water, which helps to nourish and protect the ocular surface. Lacrimal gland secretion is primarily under neural control, which is achieved through a neural reflex arc. Stimuli to the ocular surface activate afferent sensory nerves in the cornea and conjunctiva. This in turn activates efferent parasympathetic and sympathetic nerves in the lacrimal gland to stimulate secretion. Sex steroid hormones are also important regulators of lacrimal gland functions. A decrease or lack of lacrimal gland secretion is the leading cause of aqueous tear deficient dry eye syndrome (DES). It has been suggested that DES is an inflammatory disorder that affects the ocular surface and the lacrimal gland. In several pathological instances, the lacrimal gland can become a target of the immune system and show signs of inflammation. This can result from autoimmune diseases (Sjögren's syndrome), organ transplantation (graft versus host disease), or simply as a result of aging. The hallmarks of lacrimal gland inflammation are the presence of focal lymphocytic infiltrates and increased production of proinflammatory cytokines. The mechanisms leading to lacrimal gland dysfunction are still poorly understood. Apoptosis, production of autoantibodies, hormonal imbalance, alterations in signaling molecules, neural dysfunction, and increased levels of proinflammatory cytokines have been proposed as possible mediators of lacrimal gland insufficiency in disease states.

Essential role of STAT3 in cytokine-driven NF-kappaB-mediated serum amyloid A gene expression

Serum amyloid A (SAA) is a sensitive marker of acute-phase responses and known as a precursor protein of amyloid fibril in amyloid A (AA) (secondary) amyloidosis. Since the serum SAA level is also closely related to activity of chronic inflammatory disease and coronary artery disease, it is important to clarify the exact induction mechanism of SAA from the clinical point of view. Here we provide evidence that STAT3 plays an essential role in cytokine-driven SAA expression, although the human SAA gene shows no typical STAT3 response element (RE) in its promoters. STAT3 and nuclear factor kappaB (NF-kappaB) p65 first form a complex following interleukin (IL)-1 and IL-6 (IL-1+6) stimulation, after which STAT3 interacts with nonconsensus sequences at a 3' site of the SAA gene promoter's NF-kappaB RE. Moreover, co-expression of p300 with STAT3 dramatically enhances the transcriptional activity of SAA. The formation of a complex with STAT3, NF-kappaB p65, and p300 is thus essential for the synergistic induction of the SAA gene by IL-1+6 stimulation. Our findings are expected to aid the understanding of the inflammatory status of AA amyloidosis to aid development of a therapeutic strategy for this disease by means of normalization of serum SAA levels.

Suppressive effects of QFGJS, a preparation from an anti-arthritic herbal formula, on rat experimental adjuvant-induced arthritis

To analyze the anti-arthritic effects of QFGJS (a pharmaceutical preparation from herbs) on rheumatoid arthritis, adjuvant-induced arthritis (AIA) was established in male SD rats, and two administration protocols, i.e., oral treatment with different doses of QFGJS on the day of arthritis induction or on the day when visible clinical signs of arthritis occurred, were initiated and continued until day 30. Treatments with QFGJS using both administration protocols significantly suppressed the incidence and severity of arthritis in a dose-dependent manner, showing dramatic reduction of paw swelling and ESR throughout the disease progression of AIA. Radiological and histopathological examinations showed markedly decreased tissue and bone destruction of ankle joints in the QFGJS-treated rats. The serum levels of TNF-alpha, IL-1beta, and IL-6 were significantly decreased in the QFGJS-treated rats. QFGJS demonstrates pronounced anti-arthritic effects on AIA, indicating that this herbal preparation would be a potent candidate as a novel botanical drug for further investigation.

Study of etanercept, a tumor necrosis factor-alpha inhibitor, in recurrent ovarian cancer

PURPOSE

Convincing data support the link between inflammation and ovarian cancer. Tumor necrosis factor-alpha (TNF-alpha), a major mediator of inflammation, is chronically produced in the ovarian tumor microenvironment and may enhance tumor growth and invasion by inducing the secretion of cytokines, proangiogenic factors, and metalloproteinases. Etanercept is a recombinant human soluble p75 TNF receptor that binds to TNF-alpha and renders it biologically unavailable. In the current study, we sought to determine the toxicity, biologic activity, and therapeutic efficacy of etanercept in recurrent ovarian cancer.

PATIENTS AND METHODS

We initiated a phase I-B, nonrandomized, open-label study in patients with recurrent ovarian cancer. Etanercept was administered subcutaneously at a dose of 25 mg twice weekly (cohort one) and 25 mg thrice weekly (cohort two) until disease progression.

RESULTS

Thirty patients were recruited (cohort one, 17 patients; cohort two, 13 patients). Eighteen of the 30 patients (cohort one, 11 patients; cohort two, seven patients) completed > or = 12 weeks of treatment. Six patients achieved prolonged disease stabilization (cohort one, two patients [40 and 25 weeks]; cohort two, four patients [34, 24, 22, and 24 weeks]). A significant rise in immunoreactive TNF was seen in all patients (pretreatment compared with end of treatment). A phytohemagglutinin-stimulated whole-blood cytokine assay showed a significant fall in interleukin-6 (cohort one [11 of 17]) and CCL2 (cohort one [13 of 17]) levels. Common adverse effects were injection-site reactions and fatigue.

CONCLUSION

We provide evidence for the biologic activity and safety of etanercept in recurrent ovarian cancer. Our data suggest possible clinical activity that must be confirmed in future studies.

FK506 inhibits prostaglandin E2 production from synovial cells by suppressing peripheral blood mononuclear cells

FK506, an immunosuppressive drug for T cells, reduces pain in patients with rheumatoid arthritis. However, the mechanism for pain reduction remains uncharacterized. In this study, we investigated the effect of FK506 on prostaglandin E(2) (PGE(2)) production from synovial cells in vitro. Human synovial cells were cultured with supernatant from peripheral blood mononuclear cells (PBMC) stimulated with anti-CD3 plus anti-CD28 antibodies. Cultured synovial cells with PBMC supernatant produced a high amount of PGE(2) and FK506 inhibited PGE(2) induction from synovial cells. Culture supernatant contained interleukin-1beta (IL-1beta) and TNFalpha, and FK506 suppressed both in PBMC supernatant. Anti-IL-1beta neutralizing antibody, but not anti-TNFalpha neutralizing antibody, completely inhibited PGE(2) induction by PBMC supernatant. These results suggest that FK506 suppresses inflammation by inhibiting PGE(2) production from synovial cells through suppression of IL-1beta production from leukocytes.

Infliximab treatment reduces complement activation in patients with rheumatoid arthritis

BACKGROUND

Tumour necrosis factor (TNF) blocking agents decrease C reactive protein (CRP) levels in rheumatoid arthritis (RA). It has been shown that CRP may contribute to complement activation in RA.

OBJECTIVE

To assess the effect of intravenous infliximab treatment on complement activation, especially that mediated by CRP, in RA.

METHODS

35 patients with active RA (28 joint count Disease Activity Score (DAS28) >4.4) were treated with intravenous injections of infliximab (3 mg/kg, at weeks 0, 2, 6, 14, and 22). Clinical response and plasma levels of complement activation products, of CRP and of CRP-complement complexes, which are specific markers for CRP mediated complement activation, were assessed at the indicated time points up to 22 weeks. The relationship between CRP and CRP-complement complexes was analysed by paired t test between two time points and by generalised estimated equation, to test differences of variables over time.

RESULTS

At 2 weeks after the first dose, infliximab significantly reduced overall C3 and C4 activation and plasma levels of CRP and CRP-complement complexes were also significantly reduced at this time point. The effects of infliximab on CRP and complement continued throughout the observation period and were more pronounced in patients with a good response to infliximab treatment.

CONCLUSION

Treatment with infliximab decreases plasma levels of CRP and CRP dependent complement activation products and concomitantly may reduce complement activation in RA. Complement activation may be among the effector mechanisms of TNF in RA.

Anti-inflammatory and analgesic effects of atorvastatin in a rat model of adjuvant-induced arthritis

Statins exert favorable effects on lipoprotein metabolism but may also possess anti-inflammatory effects. Here, we explored the effects of atorvastatin in a model of adjuvant-induced arthritis in rat. Oral treatment with atorvastatin (1-10 mg/kg) from days 10 to 15 after arthritis induction caused inhibition of the increase in paw volume. Maximal inhibition occurred at a dose of 10 mg/kg. At this dose, atorvastatin markedly ameliorated the histopathological findings of joints obtained from day 16 of arthritic animals. This was mirrored by an effective blockade of neutrophil influx, as assessed by the tissue myeloperoxidase levels. The concentrations of the cytokines interleukin-1beta, interleukin-6 and tumor necrosis factor-alpha and the chemokines CCL5 and CCL2 were significantly decreased in arthritic rats treated with atorvastatin. In contrast, the levels of interleukin-10 were enhanced by the drug treatment. The drug also prevented the hypernociception observed in the inflamed joints. These data clearly illustrate the therapeutic potential of a statin-sensitive pathway in inflammatory arthritis.

Tumour necrosis factor alpha as a therapeutic target for immune-mediated inflammatory diseases

Preclinical studies have identified and validated tumour necrosis factor alpha (TNFalpha) as a key disease molecule and therapeutic target for immunotherapeutic intervention in many immune-mediated inflammatory diseases. Clinical indications include rheumatoid arthritis, Crohn's disease, ankylosing spondylitis and psoriasis. Recent clinical findings indicate that many chronic inflammatory disorders share certain pathogenic pathways, whereas others are limited to particular disease phenotypes. Better understanding of these pathogenic pathways will inform the development of new therapeutic approaches leading to more complete and sustained disease remissions.

Involvement of TNF and NF-κB in the Transcriptional Control of Cyclooxygenase-2 Expression by IFN-γ in Macrophages

IFN-gamma induces cyclooxygenase (COX)-2 expression and PG production in mouse macrophage cells. IFN-gamma activates COX-2 promoter-driven transcription. Deletion of the IFN sequence regulatory element (ISRE) I -1541/-1522 and ISRE II -1215/-1206 sites of the mouse COX-2 promoter minimally decrease this IFN-gamma induction. In contrast, deletion of the -965/-150 region from the COX-2 promoter abrogated IFN-gamma induction. In this region a NF-kappaB site has been described and mutation of this site impairs the induction of the full COX-2 promoter by IFN-gamma. Moreover, IFN-gamma induction of the COX-2 promoter was also strongly reduced by transfection of plasmid encoding the NF-kappaB inhibitor, IkappaBalpha. Interestingly, IFN-gamma induction of the COX-2 and PGE(2) synthesis was absent in macrophages from TNF(-/-) mice, and neutralizing anti-TNF Abs inhibited COX-2 promoter induction by IFN-gamma in RAW 264.7 macrophages. Moreover, NF-kappaB activity was induced late after stimulation with IFN-gamma correlating with the effect of autocrine TNF, and this NF-kappaB activation was absent in macrophages from TNF(-/-) mice. Taken together our results suggest a model in which IFN-gamma-induced TNF activates NF-kappaB, which is required for full COX-2 expression.

Reduction of the incidence and severity of collagen-induced arthritis by constitutive Nur77 expression in the T cell lineage

OBJECTIVE

To test the hypothesis that constitutive expression of Nur77 in the T cell lineage will suppress the development and pathogenesis of collagen-induced arthritis (CIA) and to understand the mechanisms by which Nur77 overexpression influences the arthritogenic response to type II collagen (CII).

METHODS

Nur77-transgenic and wild-type C57BL/6 mice were immunized with CII and were monitored for the development and severity of arthritis. Pathologic changes were examined by histology and radiography. The effects of Nur77 overexpression on immune responses were evaluated by cytokine production in vitro and serum levels of CII-specific antibodies. Sensitivity of T cells to apoptosis induction was analyzed in vitro following stimulation with anti-CD3 monoclonal antibody or glucocorticoid.

RESULTS

The incidence and severity of CIA was significantly decreased in Nur77-transgenic mice compared with wild-type controls. Attenuation of the disease was associated with increased apoptosis induction in transgenic T cells and decreased production of CII-specific IgG2a antibodies in transgenic mice. Overexpression of Nur77 in the T cell compartment did not affect Th1/Th2 cytokine production or balance.

CONCLUSION

Nur77 overexpression in the T cell lineage attenuates the development and progression of CIA, probably by promoting activation-induced T cell apoptosis and by inhibiting CII-specific antibody production.

Targeting interleukin-15 in patients with rheumatoid arthritis: A proof-of-concept study

OBJECTIVE

Interleukin-15 (IL-15) is a proinflammatory, innate response cytokine that mediates pleiotropic effector function in rheumatoid arthritis (RA) inflammatory synovitis. Our objective was to study the ability of HuMax-IL15, a human IgG1 anti-IL-15 monoclonal antibody, to neutralize exogenous and endogenous IL-15 activity in vitro and to perform a phase I-II dose-escalation trial with HuMax-IL15 in patients with active RA.

METHODS

Mononuclear cells from blood and synovial fluid (SF) of RA patients were isolated and cultured in vitro under experimental conditions involving the addition of HuMax-IL15. HuMax-IL15 was administered to 30 RA patients who received no other disease-modifying antirheumatic drugs in a 12-week, dose-ascending, placebo-controlled, double-blind, phase I-II proof-of-concept study.

RESULTS

In vitro studies showed that HuMax-IL15 suppressed proliferation and induced apoptosis in an IL-15-dependent cell line, BDB2, and was capable of suppressing the release of interferon-gamma by synovial fluid mononuclear cell (SFMC) cultures induced by exogenous IL-15. Furthermore, HuMax-IL15 F(ab')2 fragments suppressed exogenous IL-15-induced CD69 expression in RA peripheral blood mononuclear cells and SFMCs, which indicates that HuMax-IL15 can specifically neutralize several biologic effects of IL-15 in synovial tissue in vitro. In a phase I-II clinical trial, HuMax-IL15 was well tolerated clinically, with no significant effects on T lymphocyte subset and natural killer cell numbers. Substantial improvements in disease activity were observed according to the American College of Rheumatology criteria for 20% improvement (63% of patients), 50% improvement (38%), and 70% improvement (25%).

CONCLUSION

These clinical data suggest for the first time that IL-15 could represent a novel therapeutic target in RA.

Blockade of lymphotoxin pathway exacerbates autoimmune arthritis by enhancing the Th1 response

OBJECTIVE

To study the role of the lymphotoxin (LT) signaling pathway in the development and pathogenesis of collagen-induced arthritis (CIA), and to understand the mechanisms by which blockade of the LT pathway influences the arthritogenic response to type II collagen (CII).

METHODS

LTalpha-deficient and wild-type C57BL/6 mice were immunized with CII. Male DBA/1 mice were immunized with CII and treated with LTbeta receptor immunoglobulin fusion protein (LTbetaR-Ig) or control Ig. Mice were monitored for the development and severity of arthritis. The effects of LT blockade on immune responses were evaluated by cytokine production and antigen-specific proliferation in vitro, the delayed-type hypersensitivity (DTH) response, and serum levels of CII-specific antibodies.

RESULTS

CIA that developed in LTalpha-deficient mice was more severe and prolonged than that which developed in wild-type mice. Blocking LT signaling with LTbetaR-Ig significantly exacerbated the disease. Exacerbation of CIA was associated with an enhanced Th1-type response, including increased type 1 cytokine production, an enhanced DTH response, and elevated production of CII-specific IgG2a antibodies.

CONCLUSION

Blockade of the LT signaling pathway exacerbates the development and progression of CIA, probably by skewing the Th1/Th2 balance that determines the outcome of autoimmune responses.

Decrease of anti-cyclic citrullinated peptide antibodies and rheumatoid factor following anti-TNFalpha therapy (infliximab) in rheumatoid arthritis is associated with clinical improvement

OBJECTIVE

To investigate the effect of infliximab treatment on anti-cyclic citrullinated peptide antibodies (anti-CCP) and rheumatoid factor (RF) in patients with rheumatoid arthritis.

METHODS

43 patients with rheumatoid arthritis not responding to disease modifying anti-rheumatic drugs (DMARD) received intravenous infliximab at a dose of 3 mg/kg at baseline and after two and six weeks, and subsequently bimonthly, in combination with methotrexate. Serum samples were collected at baseline and at week 24. A commercial enzyme linked immunosorbent assay was used to test for anti-CCP antibodies; RF were detected using a quantitative nephelometric assay.

RESULTS

At baseline, 38 of the 43 patients (88%) were positive for anti-CCP antibodies, and 41 (95%) were positive for RF. The serum titre of anti-CCP and RF decreased significantly after six months of treatment (p = 0.0001 and p<0.0001, respectively). When the patients were grouped on the basis of their clinical response to infliximab, a significant decrease in serum anti-CCP antibodies and RF was observed only in patients who had clinical improvement (ACR 20 and ACR 50).

CONCLUSIONS

Anti-TNFalpha treatment in rheumatoid arthritis results in a decrease in the serum titres of RF and anti-CCP antibodies in patients showing clinical improvement, suggesting that these measurements may be a useful adjunct in assessing treatment efficacy.

Molecular targeting of angiogenesis for imaging and therapy

Angiogenesis, i.e. the proliferation of new blood vessels from pre-existing ones, is an underlying process in many human diseases, including cancer, blinding ocular disorders and rheumatoid arthritis. The ability to selectively target and interfere with neovascularisation would potentially be useful in the diagnosis and treatment of angiogenesis-related diseases. This review presents the authors' views on some of the most relevant markers of angiogenesis described to date, as well as on specific ligands which have been characterised in pre-clinical animal models and/or clinical studies. Furthermore, we present an overview on technologies which are likely to have an impact on the way molecular targeting of angiogenesis is performed in the future.

Current Gene-Mapping Strategies in Experimental Models of Multiple Sclerosis

Both family-based linkage analyses and population-based association studies have failed to identify disease-regulatory non-human leucocyte antigen genes of importance in multiple sclerosis (MS). Instead, investigators have employed experimental models, which offer major advantages in genetic studies. We summarize the current main methodologies used and the status of both the human and experimental approaches. Why is it important to find genes regulating MS? There is an immense number of cellular and molecular interactions defined in the immunological field and it is very difficult to unravel those that are critical to an inflammatory disease, such as MS, by classical hypothesis-driven research. Unbiased genetics defines evolutionary conserved gene polymorphisms and pathways regulated by these genes, which are central in the pathogenesis. These, in turn, are of interest as therapeutic targets and pharmacogenetic markers.

Secretion of oncostatin M by neutrophils in rheumatoid arthritis

OBJECTIVE

Neutrophils are known to express and release a large number of proinflammatory cytokines when they are stimulated by inflammatory stimuli. The objective of this study was to determine whether neutrophils express oncostatin M (OSM), a member of the interleukin-6 family of cytokines that has been implicated in the pathogenesis of inflammatory joint disease.

METHODS

Neutrophils were isolated from the blood of healthy volunteer donors and from the blood and synovial fluid of patients with rheumatoid arthritis (RA). OSM levels were measured in cell extracts and in culture supernatants by Western blotting. Total RNA was isolated from control and granulocyte-macrophage colony-stimulating factor (GM-CSF)-treated neutrophils, and OSM messenger RNA levels were quantified by hybridization of a radiolabeled probe.

RESULTS

GM-CSF stimulated a rapid and transient expression and release of OSM from blood neutrophils, which was more rapid than the expression and release from blood monocytes. A 28-kd protein was identified in cell extracts, but an additional 25-kd isoform was detected in culture supernatants. Synovial fluid neutrophils could not be stimulated to express OSM, but this cytokine was detected in cell-free supernatants at various levels.

CONCLUSION

Blood neutrophils can be stimulated to express and rapidly release large quantities of OSM. We propose that this important cytokine is released from neutrophils as they infiltrate rheumatoid joints and, thus, contribute to the complex cytokine network that characterizes RA.

In vitro study of regulation of IL-6 production in bronchiectasis

Persistent airway inflammation is an important pathogenetic factor in bronchiectasis, and interleukin (IL)-6 is among the mediators implicated in regulation of inflammation in bronchiectatic airways. We postulated that airway secretion with its constituents of cytokines and enzymes would provide an environment for perpetuation of inflammation in vivo. We aimed to determine the action of sputum from patients with bronchiectasis on IL-6 production from cultured normal human bronchial epithelial (NHBE) cells and its modulation by anti-inflammatory drugs in vitro. Cultures of NHBE cells were tested with (i) sputum of bronchiectatic patients, (ii) anti-tumor necrosis factor-alpha (TNF-alpha) pre-treated sputum, or (iii) recombinant human (rh)-TNF-alpha. Alternatively, NHBE cells were incubated with one of the anti-inflammatory drugs before treatment with sputum or rh-TNF-alpha. IL-6 produced into the medium was assayed by ELISA. Sputum in bronchiectasis stimulated IL-6 production from NHBE cells by 1.9 times. This was largely attributable to TNF-alpha as pre-incubation of sputum sol with anti-TNF-alpha almost neutralized the sputum effect. Apart from dexamethasone, the other drugs exerted inhibitory effects on IL-6 production. Ibuprofen suppressed sputum-stimulated IL-6 production to levels above control and effect levelled off at 50-100 microg/mi, contrasting the dose-dependent suppression to control level with MK-663 (0.1-10 microg/ml) and to sub-control levels with triptolide (20-1000 ng/ml). Our results support that sputum in bronchiectasis can stimulate IL-6 production from NHBE cells, and TNF-alpha is an important cytokine mediating the process. The suppressive effects observed with ibuprofen, triptolide and MK-663 warrant further study.

Tumour necrosis factor in sarcoidosis and its potential for targeted therapy

Tumour necrosis factor (TNF)-alpha is a potent cytokine involved in the inflammatory reactions of many acute and chronic diseases. Recently, agents that block TNFalpha either directly or indirectly have been successful in the treatment of a variety of immune-mediated inflammatory disorders including rheumatoid arthritis and Crohn's disease. Sarcoidosis is an immune-mediated inflammatory disorder characterised by the formation of granulomas. TNFalpha is important in the initiation and perpetuation of inflammation in sarcoidosis, contributing to the initiation of granulomas and the progression of fibrosis, as well as to nongranulomatous inflammation. Various agents used to treat sarcoidosis affect TNF, including the most widely used drug class, corticosteroids, which are usually effective in blocking TNFalpha release from cells. Other agents that nonspecifically inhibit TNFalpha release include methotrexate, azathioprine and pentoxifylline. Specific TNF-antagonising biological agents such as infliximab and etanercept are being tested in patients with sarcoidosis, with mixed success. Infliximab has been shown to produce clinical improvement and reduce the requirement for corticosteroids in a small number of patients with sarcoidosis. However, as infliximab can be associated with reactivation of tuberculosis, which could be mistaken as worsening sarcoidosis, it should be used with caution in this patient group.

The non-classical export routes: FGF1 and IL-1alpha point the way

Non-classical protein release independent of the ER-Golgi pathway has been reported for an increasing number of proteins lacking an N-terminal signal sequence. The export of FGF1 and IL-1alpha, two pro-angiogenic polypeptides, provides two such examples. In both cases, export is based on the Cu2+-dependent formation of multiprotein complexes containing the S100A13 protein and might involve translocation of the protein across the membrane as a 'molten globule'. FGF1 and IL-1alpha are involved in pathological processes such as restenosis and tumor formation. Inhibition of their export by Cu2+ chelators is thus an effective strategy for treatment of several diseases.

Comparison of ultrasonographic assessment of synovitis and joint vascularity with radiographic evaluation in a randomized, placebo-controlled study of infliximab therapy in early rheumatoid arthritis

OBJECTIVE

To investigate sensitive ultrasonographic imaging methods for detection of synovial thickness and vascularity to discriminate between patients with early rheumatoid arthritis (RA) receiving infliximab + methotrexate (MTX) versus placebo + MTX over 18 weeks, and to compare the relationship between synovial thickening and vascularity at baseline and radiologic damage to joints of the hands and feet at 54 weeks.

METHODS

Patients with early RA (duration <3 years) receiving stable dosages of MTX were randomly assigned to receive blinded infusions of 5 mg/kg infliximab (n = 12) or placebo (n = 12) at weeks 0, 2, 6, and then every 8 weeks until week 46. At baseline and week 18, clinical assessments were performed, and metacarpophalangeal joints were assessed by high-frequency ultrasonography and power Doppler ultrasonography measurements. Radiographs of the hands and feet taken at baseline and at 54 weeks were evaluated using the van der Heijde modification of the Sharp method (vdH-Sharp score).

RESULTS

Using changes in the total vdH-Sharp score over 54 weeks and changes in synovial thickening and joint vascularity at 18 weeks, we were able to distinguish those patients receiving infusions of infliximab + MTX from those receiving placebo + MTX. Sonographic measurements of synovial thickening and vascularity at baseline in the placebo + MTX group demonstrated clear relationships with the magnitude of radiologic joint damage at week 54. Infliximab + MTX treatment abolished these relationships.

CONCLUSION

The delay or reversal of inflammatory and joint-destructive mechanisms in patients with early RA was already apparent following 18 weeks of treatment with infliximab + MTX and was reflected in radiologic changes at 54 weeks.

Tumor necrosis factor-alpha blockade for the treatment of acute GVHD

Despite posttransplantation immunosuppressive therapy, acute graft-versus-host disease (GVHD) remains a major cause of sickness and death. Tumor necrosis factor-alpha (TNF-alpha) is implicated in the pathophysiology of GVHD at several steps in the process. Infliximab is a genetically constructed immunoglobulin G1 (IgG1) murine-human chimeric monoclonal antibody that binds the soluble subunit and the membrane-bound precursor of TNF-alpha, blocking its interaction with receptors and causing lysis of cells that produce TNF-alpha. In this study we retrospectively evaluated 134 patients who had steroid-refractory acute GVHD. Of these, 21 who received infliximab as a single agent were analyzed. The overall response rate was 67% (n = 14), and 13 patients (62%) experienced complete response (CR). Five patients (24%) did not respond, and 2 (10%) had progressive GVHD. None had a toxic reaction to infliximab. Ten patients (48%) had 18 fungal infections, including Aspergillus species in 7 and Candida species in 10. Seventeen patients (81%) had bacterial infections, including 32 gram-positive and 8 gram-negative infections. Viral infections, primarily cytomegalovirus reactivation, occurred in 14 patients (67%). The Kaplan-Meier estimate of overall survival was 38%. In conclusion, infliximab was well tolerated and active for the treatment of steroid-resistant acute GVHD, particularly with gastrointestinal tract involvement. Survival after steroid-resistant acute GVHD continues to be problematic. The possibility of excessive fungal and other infections must be explored further.

Regulation of the human acute phase serum amyloid A genes by tumour necrosis factor-alpha, interleukin-6 and glucocorticoids in hepatic and epithelial cell lines

The major acute-phase protein serum amyloid A, A-SAA, is upregulated by a variety of inflammatory stimuli, including cytokines and glucocorticoids (GCs). Elevated systemic concentrations of both A-SAA and tumour necrosis factor (TNF)-alpha are a feature of inflammatory diseases, such as rheumatoid arthritis and inflammatory bowel disease. Here, we examine the roles of TNF-alpha, interleukin-6 (IL-6) and GCs on the transcriptional regulation of the two human A-SAA genes (SAA1 and SAA2) and show that these stimuli have different effects on the SAA1 and SAA2 promoters in HepG2 hepatoma and KB epithelial cell lines. Both genes are induced modestly by TNF-alpha and IL-6 alone and synergistically by TNF-alpha plus IL-6. The TNF-driven induction of SAA1, but not that of SAA2, can be enhanced by GCs in both cell lines, whereas GCs alone can upregulate SAA1 only in epithelial cells. The upregulation of both genes by cytokines, and of SAA1 by GCs, is more rapid in epithelial cells than hepatoma cells. We established that the order in which either cell line was treated with TNF-alpha and IL-6 influenced A-SAA promoter transcriptional activation. Treatment with TNF-alpha followed by IL-6 resulted in a much greater induction of both A-SAA genes than treatment with IL-6 followed by TNF-alpha.

Short- and long-term effects of T-cell modulating agents in experimental autoimmunity

Due to the easy and reliable induction of a disease condition with many of the features present in human autoimmunity, mercury-induced autoimmunity (mHgAI) in rodents is a favourable autoimmune model. Genetically susceptible (H-2(s)) mice develop in response to mercury (Hg) a systemic autoimmune condition with antinucleolar antibodies (ANoA) targeting the protein fibrillarin, transient polyclonal B-cell activation, hyperimmunoglobulinemia, and systemic immune-complex (IC) deposits. In order to study the short- and long-term effects of treatment with immunomodulating agents on the disease parameters in HgAI, groups of B10.S (H-2(s)) mice were given 6 mg HgCl(2)/l drinking water for 22 weeks. Three weeks initial treatment with cyclosporin A (CyA), a high dose of tacrolimus (HD tacrolimus), or anti-CD4 monoclonal antibody (a-CD4) inhibited induction of ANoA and IC deposit by Hg. This effect persisted for the subsequent 19 weeks when the mice were only treated with Hg. Initial treatment with anti-IL-4 monoclonal antibody (a-IL-4) for 3 weeks inhibited induction of IgE and IC deposits by Hg, but not ANoA. However, subsequent treatment with Hg without a-IL-4 for 19 weeks induced IC deposits. The T-cell modulating agents aggravated some of the HgAI disease parameters: a-CD4 stimulated the polyclonal B-cell activation, a-IL-4 increased the IgG antichromatin antibody response, and a low dose of tacrolimus (LD tacrolimus) enhanced the ANoA, the polyclonal B-cell activation, and the IC deposits. We conclude that a short initial treatment with a-CD4 or CyA efficiently protects against induction of systemic autoimmunity for an extended period of time. However, some of the T-cell modulating agents, especially a low dose of tacrolimus, aggravate autoimmune manifestations not only during ongoing treatment, but also after treatment with these agents has ceased.

Drugs that block tumour necrosis factor: experience in patients with rheumatoid arthritis

Three biological response modifiers that inhibit tumour necrosis factor-alpha (TNF-alpha) are approved for treating rheumatoid arthritis (RA). Etanercept is a fusion protein comprising two soluble human TNF-alpha receptors linked to the Fc fragment of human immunoglobulin G1. Infliximab is a chimeric (human/mouse) monoclonal antibody and adalimumab is a humanised monoclonal antibody. In placebo-controlled trials in established disease-modifying antirheumatic drug (DMARD)-refractory RA, the anti-TNF-alpha agents have reduced disease activity, as monotherapy or in combination with methotrexate. In long-term, open-label studies with etanercept or adalimumab, clinical response was sustained for up to 5 years. In early RA, etanercept has similar efficacy to methotrexate. However, etanercept was more effective than methotrexate in preventing radiographic progression. Preventing or delaying disease progression and disability with etanercept therapy in early RA may reduce costs associated with long-term disease outcomes. Data also suggest a benefit of infliximab plus methotrexate or adalimumab plus methotrexate in early RA. All three agents have been shown to improve functionality as assessed by health assessment questionnaire (HAQ) disability scores. Health-related quality of life is also improved in terms of physical and mental health and vitality. Furthermore, etanercept and adalimumab are associated with a reduction in fatigue. Long-term etanercept or infliximab therapy is associated with increased job employment and etanercept also reduces healthcare utilisation. Mild, transient injection-site reactions occur in about 33% of patients treated with etanercept and 20% of patients treated with adalimumab. In patients treated with infliximab, 16-20% have infusion reactions. The incidence of serious infection associated with etanercept and infliximab was low, about 2-3% in etanercept studies of up to 5 years duration, and 5% in a survey of more than 10 infliximab trials. This paper reviews the evidence for efficacy, safety and effectiveness of anti-TNF-alpha agents in RA.

Infliximab: a new therapeutic agent in acute pancreatitis?

PURPOSE

Tumor necrosis factor alpha (TNF-alpha) has a central role in the pathogenesis of acute pancreatitis and related systemic complications. The aim of this study is to investigate the therapeutic effectiveness of monoclonal TNF antibody (infliximab) in acute edematous and severe necrotizing pancreatitis models in rats.

METHODS

One hundred rats were randomly divided into 10 groups. Acute edematous pancreatitis (AEP) was induced by injection of cerulein 20 microg/kg 4 times subcutaneously at hourly intervals. Severe necrotizing pancreatitis (SNP) was induced by retrograde injection of 3% taurocholate into the common biliopancreatic duct. Infliximab 8 mg/kg was given via intravenous infusion. Serum amylase activity, pancreatic histopathology, myeloperoxidase enzyme activity (MPO), and pulmonary changes were assessed.

RESULTS

Infliximab treatment significantly decreased serum amylase activity (11939 +/- 1914 U/L versus 3458 +/- 915 U/L, P < 0.001) and histopathologic score (4.1 +/- 0.5 versus 1.5 +/- 0.3, P < 0.001) in AEP. It also suppressed neutrophil infiltration and MPO activity of the pancreatic tissue. In SNP, infliximab treatment was found to decrease pathologic score (9.4 +/- 1.2 versus 3.6 +/- 0.8, P < 0.001) and serum amylase activity (20442 +/- 2375 versus 8990 +/- 1730, P < 0.01). It ameliorated both parenchymal and fatty tissue necrosis of the pancreas. Infliximab also alleviated alveolar edema and acute respiratory distress syndrome like pulmonary complications, but the difference was not significant.

CONCLUSIONS

Chimeric TNF antibody, infliximab, should be evaluated for treatment of acute pancreatitis.

CITED2-mediated regulation of MMP-1 and MMP-13 in human chondrocytes under flow shear

CITED2 (CBP/p300-interacting transactivator with ED-rich tail 2) is a member of the Cited family of nuclear regulators, previously known as mrg1 (melanocyte-specific gene-related gene 1). CITED2 is inducible by varying stimuli including lipopolysaccharide, hypoxia, and cytokines such as interleukin 9 and interferon gamma. Using the immortalized human chondrocyte cell line, C-28/I2, we investigated whether CITED2 could be responsive to mechanical stimuli, and if so, whether CITED2 could mediate shear-driven regulation of matrix metalloproteinase (MMP) genes. The C-28/I2 cells were cultured under flow shear at 1-20 dyn/cm2, and the role of CIT-ED2 in regulation of MMPs was examined using the plasmids encoding sense and antisense CITED2 DNA sequences. The results showed that flow shear at 5 dyn/cm2 increased CITED2 mRNA and protein levels and down-regulated MMP-1 and MMP-13 mRNA and protein levels as well as enzyme activities. Consistent with the coordinated expression patterns of CITED2 and MMPs, overexpression of CITED2 repressed MMP-1 and MMP-13 mRNA levels and activities, whereas antisense CITED2 plasmids prevented the shear-induced down-regulation of MMP expression. Interleukin-1beta induced the formation of p300-Ets-1 complexes without affecting expression of CITED2. Transforming growth factor-beta as well as flow shear at 5 dyn/cm2 stimulated not only the expression of CITED2 but also the association of CIT-ED2 with p300 by dissociating Ets-1 from p300. These results indicate that CITED2 plays a major role in shear-induced down-regulation of MMP-1 and MMP-13 via a transforming growth factor-beta-dependent pathway.

Regulation and localization of endogenous human tristetraprolin

Tumor necrosis factor (TNF) has been implicated in the development and pathogenicity of infectious diseases and autoimmune disorders, such as septic shock and arthritis. The zinc-finger protein tristetraprolin (TTP) has been identified as a major regulator of TNF biosynthesis. To define its intracellular location and examine its regulation of TNF, a quantitive intracellular staining assay specific for TTP was developed. We establish for the first time that in peripheral blood leukocytes, expression of endogenous TTP is confined to the cytoplasm. Baseline expression of TTP was higher in monocytes than in lymphocytes or neutrophils. After in vitro incubation with lipopolysaccharide (LPS), leukocyte TTP levels increased rapidly, peaking after approximately 2 hours. Monocytes showed the greatest response to LPS stimulation and lymphocytes the least. TTP levels were also studied in leukocytes isolated from healthy volunteers infused with a bolus dose of LPS. TTP expression and initial upregulation in response to LPS infusion were consistent with the in vitro data. Neutrophil TTP levels responded first, reaching an initial peak within 1 hour, monocyte levels peaked next at 2 hours, followed by lymphocytes at 4 hours. This response paralleled plasma TNF levels, which peaked 2 hours after infusion and were no longer detectable after 12 hours. A second rise in intracellular TTP levels, which did not parallel plasma TNF levels, was observed in all leukocyte populations, starting 12 hours after infusion. These data establish the cytoplasmic location of TTP, supporting a major role for this protein in regulating TNF production, and suggest that TTP levels are not regulated solely by TNF.

Human cellular inflammation in the pathology of acute cerebral ischaemia

Leucocytes form important effector pathways for inflammation. This article reviews the clinical evidence for the presence of a cellular inflammatory response in cerebral ischaemia, and attempts to define its temporal profile and spatial distribution. The processes involved in recruitment and activation of leucocytes in this context are addressed, and the successes and failures of interventions aimed at these processes discussed.

Expression, localization, and functional activity of TL1A, a novel Th1-polarizing cytokine in inflammatory bowel disease

TL1A is a novel TNF-like factor that acts as a costimulator of IFN-gamma secretion through binding to the death domain-containing receptor, DR3. The aim of this study was to test the hypothesis that TL1A may play an important role in inflammatory bowel disease (IBD) by functioning as a Th1-polarizing cytokine. The expression, cellular localization, and functional activity of TL1A and DR3 were studied in intestinal tissue specimens as well as isolated lamina propria mononuclear cells from IBD patients and controls. TL1A mRNA and protein expression was up-regulated in IBD, particularly in involved areas of Crohn's disease (CD; p < 0.03 vs control). TL1A production was localized to the intestinal lamina propria in macrophages and CD4(+) and CD8(+) lymphocytes from CD patients as well as in plasma cells from ulcerative colitis patients. The amount of TL1A protein and the number of TL1A-positive cells correlated with the severity of inflammation, most significantly in CD. Increased numbers of immunoreactive DR3-positive T lymphocytes were detected in the intestinal lamina propria from IBD patients. Addition of recombinant human TL1A to cultures of PHA-stimulated lamina propria mononuclear from CD patients significantly augmented IFN-gamma production by 4-fold, whereas a minimal effect was observed in control patients. Our study provides evidence for the first time that the novel cytokine TL1A may play an important role in a Th1-mediated disease such as CD.

Tumor necrosis factor α activation of the apoptotic cascade in murine articular chondrocytes is associated with the induction of metalloproteinases and specific pro-resorptive factors

OBJECTIVE

Tumor necrosis factor alpha (TNFalpha) blockade provides substantive reduction of the symptoms of rheumatoid arthritis (RA). While the biologic actions of TNFalpha have been well characterized in immune and synovial cells, which are known to be major contributors to the progression of cartilage destruction in RA, the current studies were designed to assess the direct effects of TNFalpha on chondrocytes.

METHODS

We examined the expression of several groupings of messenger RNA (mRNA) that define key biologic pathways that have previously been associated with either the general actions of TNFalpha or cartilage destruction, in murine articular chondrocytes isolated from wild-type mice and TNFalpha receptor-null (p55/p75(-/-)) mice.

RESULTS

TNFalpha induced the expression of multiple mRNA that facilitate apoptosis and lead to apoptosis-induced cell death. The induction of apoptosis was accompanied by the increased expression of several factors involved in the regulation of skeletal tissue proteolysis and resorption. Quantitative increases from 2-fold to >10-fold were seen for inducible nitric oxide synthase, matrix metalloproteinase 3, macrophage colony-stimulating factor, and osteoprotegerin mRNA expression. The dependence of the induction of these mRNA on TNFalpha was confirmed by comparison with the effects of TNFalpha on chondrocytes isolated from receptor-null mice.

CONCLUSION

These findings demonstrate that TNFalpha alters the expression of a complex array of genes within murine chondrocytes that contribute to the destruction of joint surfaces, independent of its actions on synovial and immune cells. Further studies are needed to clarify the biologic actions of TNFalpha in human cartilage cells.

Secondary immune deficiencies associated with biological therapeutics

Biological therapeutics have been utilized in the past several years for the treatment of various autoimmune, cardiovascular, and neoplastic conditions. As these agents target both pathologic and physiologic components of inflammatory and immune systems, the scientific community has been challenged to identify potential secondary immune deficiencies associated with their use. This article will focus on biological agents used for the treatment of rheumatoid arthritis, including tumor necrosis factor-a inhibitors, cytotoxic T lymphocyte-associated antigen-4 (CTLA-4 Ig), rituximab, and interleukin-1 receptor agonist (IL-1Ra). Both clinical and in vitro studies have been done to explore the potential immunomodulatory and immunosuppressive effects of these agents.

Successful infliximab treatment of steroid and OKT3 refractory acute cellular rejection in two patients after intestinal transplantation

Acute rejection resistant to established immunosuppressive rescue protocols remains the most prominent risk factor after intestinal transplantation. In two patients presenting with steroid-resistant severe acute cellular rejection 9 months and 2 years after intestinal transplantation, complete resolution was not achieved despite 5 and 10 days of OKT3 treatment, respectively, and high-dose triple baseline immunosuppression with tacrolimus, rapamycin, and steroids. There was a dissociated course of rejection with persistent moderate to severe rejection in the terminal portion of the graft despite complete recovery from rejection in the proximal parts. Both patients were treated with four subsequent infusions of infliximab (3 mg/kg body weight), a chimeric anti-tumor necrosis factor-alpha antibody. There was an immediate response regarding macroscopic appearance, graft histology, and clinical symptoms. Both patients recovered. In conclusion, infliximab has proven to be an effective rescue therapy in a selected group of patients with steroid and OKT3 refractory severe acute rejection after intestinal transplantation.

Calcineurin inhibitors exert rapid reduction of inflammatory pain in rat adjuvant-induced arthritis

1. FK506 and cyclosporin A (CsA) are immunosuppressive drugs, that specifically inhibit T-cell activation via calcineurin inhibition. This study was undertaken to investigate whether calcineurin inhibitors exert analgesic actions in rat adjuvant-induced arthritis (AIA), an animal model of rheumatoid arthritis (RA). 2. AIA was induced in female Lewis rats. Single doses of FK506 and CsA were orally administered to arthritic rats 17 days after arthritis induction. Intensity of hyperalgesia was assessed by measuring the pain threshold of hind paws. Tumor necrosis factor (TNF)-alpha, IL-1beta and PGE(2) levels in paw extracts were determined by ELISA. TNF activity was measured by L929 cell cytotoxicity assay. IL-1beta and cyclooxygenase (COX) mRNA expression in arthritic paws were measured by RT-PCR. 3. Single doses of FK506 and CsA markedly reduced joint hyperalgesia 24 h after drug administration, without affecting inflammation in an advanced stage of AIA. 4. The calcineurin inhibitors partially reduced the elevated level of TNF-alpha in arthritic paws, however, the analgesic effects of these drugs were not associated with the reduction in TNF-alpha level. 5. Moreover, treatment with anti-rat TNF-alpha antibody did not affect the hyperalgesia, when TNF-alpha activity was suppressed in arthritic paws by that treatment. 6. Both calcineurin inhibitors reduced the elevated level of IL-1beta in arthritic paws to a normal level, 24 h after drug administration. 7. FK506 reduced IL-1beta and COX-2 mRNA expression and PGE(2) level in arthritic paws. 8 In conclusion, calcineurin inhibitors rapidly reduce joint hyperalgesia probably by downregulating IL-1beta, but not TNF-alpha, in AIA. Our findings may provide a new strategy for the treatment of pain in RA.