Tumor necrosis factor biology in experimental and clinical arthritis

The role of the cytokine TNF-α in choroidal neovascularization: a systematic review

TNF-α is a multifunctional cytokine produced by macrophages and T cells. This proinflammatory substance is considered to play a crucial role in the inflammatory process associated with age-related macular degeneration (AMD). The current review aimed to describe evidence for an association between TNF-α and AMD reported in various studies. The MEDLINE, Embase, PubMed and Global Health databases were systematically searched to identify studies that investigated the role of TNF-α in AMD. A total of 24 studies were deemed eligible for the review. To better understand and integrate the evidence, the studies were categorised into four major groups in relation to the role of TNF-α in AMD: (1) those examining biological signalling pathways through which TNF-α exerts its effect; (2) investigating levels of TNF-α; (3) exploring the genetics underlying the role of TNF-α; and (4) assessing anti-TNF-α agents as potential treatments for AMD. TNF-α is thought to directly contribute to choroidal neovascularization (CNV) enhancement and has been shown to exert its effect by augmenting the inflammatory response through other signalling pathways. Additionally, different genes have been found to be associated with activities linked to TNF-α in AMD. Overall, measurement of systemic and local levels of TNF-α has not yielded consistent findings, with variable conclusions for the role of anti-TNF-α agents in remission of AMD symptoms. The role of TNF-α in neovascular AMD is not clear, and not all anti-TNF-α agents are safe. The potential of this cytokine in atrophic AMD has not been examined. Future studies should address these unresolved questions.

Cutaneous Autoimmune Phenomena of the Anti-TNFa Biosimilars. Casebased Review

BACKGROUND

Psoriasis (Pso) is a common chronic inflammatory disease affecting the skin, both sexes, and all ages. It can be associated with other chronic inflammatory musculoskeletal disorders and certain drugs, including tumor necrosis factor α (TNFα) antagonists.

CASE PRESENTATION

A 64-year-old man with seronegative rheumatoid arthritis (RA) refractory to leflunomide and prednisone was treated with SB-4 (Benepali), an etanercept biosimilar 50mg/week subcutaneously. He responded well to the treatment, but a year later, he developed erythematous skin eruptions affecting mainly in the palms of both hands. Skin biopsy showed a picture compatible with Pso. SB-4 was discontinued, and the skin lesions disappeared with the addition of topical steroid therapy. This is the only case of psoriatic skin lesions associated with SB-4 treatment.

CONCLUSION

Thus, we review and discuss the relevant literature of Pso cases related to SB-4 and other anti-TNFα biosimilars. Rheumatologists dealing with patients on anti-TNFα biosimilars should be aware of and recognize these complications.

An unusual case of Behcet disease with posterior scleritis: A case report

RATIONALE

Posterior scleritis is an ocular inflammatory disorder that can be associated with both infectious and non-infectious immune reactions. Behcet disease is a chronic, relapsing, multisystemic inflammatory disorder with uveitis. There are no reported cases of posterior scleritis with Bechet disease.

PATIENT CONCERNS

A 50-year-old man previously diagnosed with systemic Behcet disease presented with ocular pain and decreased vision in the left eye.

DIAGNOSIS

Posterior scleritis associated with Behcet disease was diagnosed based on optical coherence tomography showing choroidal folds, as well as contrast computed tomography and ultrasound sonography demonstrating thickening of the posterior sclera.

INTERVENTIONS

Treatment with systemic corticosteroids was initiated. Since inflammation relapsed during steroid tapering, anti-tumor necrosis factor-alpha (TNF-α) therapy was used in combination, and tapering of steroids was possible without recurrence of inflammation for 12 months.

OUTCOMES

Posterior scleritis was resolved and visual acuity improved. With the continuation of TNF-α therapy, oral prednisolone was successfully tapered and discontinued. No relapse of inflammation was observed at follow-up 1 year after discontinuation of prednisolone.

LESSONS

Ophthalmologists should be aware of the possibility of rare manifestation of posterior scleritis in patients with Behcet disease, and that combined use of systemic steroids and anti-TNF-α therapy may resolve the scleritis without recurrence of inflammation.

Granuloma annulare development in a patient with rheumatoid arthritis treated with tocilizumab: case-based review

Granuloma annulare (GA) is the most common non-infectious disease. Despite the fact that it is a benign disease, it can be associated with a variety of disorders and certain drugs including biological disease-modifying anti-rheumatic drugs (bDMARDs). A 50-year-old man with a history of rheumatoid arthritis refractory to methotrexate, hydroxychloroquine and infliximab was treated with tocilizumab (TCZ), an interleukin-6 receptor antagonist, 162 mg subcutaneously every week. The patient responded very well to TCZ treatment with a decrease of acute phase reactants and reduction of disease activity score for 28-joints count. However, 3 months later he developed erythematous polycyclic eruptions affecting the lower extremities consistent with a diagnosis of GA which was confirmed by a skin biopsy. TCZ has been discontinued and the patient was treated with prednisone presenting complete resolution of skin manifestations after 4 weeks. This is the first case of GA development during TCZ treatment. Thus, we review the literature and discuss the relevant cases of GA development in patients treated with bDMARDs. When dealing with patients treated with these agents, all physicians should be aware of possible adverse events and the potential development of such complications.

An anti-TNF-α antibody mimetic to treat ocular inflammation

Infliximab is an antibody that neutralizes TNF-α and is used principally by systemic administration to treat many inflammatory disorders. We prepared the antibody mimetic Fab-PEG-Fab (FpF_infliximab) for direct intravitreal injection to assess whether such formulations have biological activity and potential utility for ocular use. FpF_infliximab was designed to address side effects caused by antibody degradation and the presence of the Fc region. Surface plasmon resonance analysis indicated that infliximab and FpF_infliximab maintained binding affinity for both human and murine recombinant TNF-α. No Fc mediated RPE cellular uptake was observed for FpF_infliximab. Both Infliximab and FpF_infliximab suppressed ocular inflammation by reducing the number of CD45+ infiltrate cells in the EAU mice after a single intravitreal injection at the onset of peak disease. These results offer an opportunity to develop and formulate for ocular use, FpF molecules designed for single and potentially multiple targets using bi-specific FpFs.

Update on intravitreal anti-tumor necrosis factor alpha therapies for ocular disorders

Tumor necrosis factor alpha (TNF-?) is an important pro-inflammatory cytokine associated with a variety of ocular diseases. The currently available TNF-? inhibitors are etanercept, infliximab, adalimumab, golimumab, and certolizumab. Experimental and clinical studies on the intravitreal use of these agents have been reported with etanercept, infliximab, and adalimumab: etanercept has shown limited efficacy in scarce reports; infliximab has been associated with local safety concerns but appears to benefit certain cases; adalimumab has shown no efficacy in cases of age-related macular degeneration (AMD) or diabetic macular edema (DME), but the combination with bevacizumab may be effective in refractory cases of macular diseases. Further preclinical and clinical studies are warranted in order to be able to obtain a more robust conclusion on the use of intravitreal TNF-? inhibitors.

Safety and tolerability of tumor necrosis factor-α inhibitors in psoriasis: a narrative review

Tumor necrosis factor (TNF)-α inhibitors are an alternative to oral systemic therapies for psoriasis. Data regarding the safety of TNF-α inhibitors from randomized clinical trials may not fully reflect the effects on the clinic patient population receiving the therapy, but other sources of information are available. We performed a literature review to assess the safety and tolerability of the treatment of moderate-to-severe plaque psoriasis with TNF-α inhibitors. A literature search was conducted using PubMed for articles dating from January 2000 to October 2013. Randomized controlled, cohort, open-label, and observational studies were included, as well as case reports and letters to the editor. Articles found on PubMed describing the safety of anti-TNF-α therapy in psoriasis patients were included, while studies highlighting interleukin (IL)-12 and IL-23 inhibitors were excluded, as were non-English articles. In total, 58 articles were included in the review. TNF-α inhibitors exhibit both efficacy and tolerability in patients with moderate-to-severe plaque psoriasis. Adverse effects associated with these medications are not common and can be minimized with routine clinical monitoring and patient education. While the risk of severe adverse events is low, the lack of very large, long-term, randomized safety trials limits the ability to fully define the safety of these agents. TNF-α inhibitors have a good efficacy/safety ratio for use in patients with moderate-to-severe psoriasis. Serious adverse effects are not common, and common injection-site reactions are usually manageable. The benefits of TNF-α inhibitors outweigh the risks for moderate-to-severe psoriasis; however, there are potential adverse effects and the patient populations at highest risk include the elderly and those with a history of malignancy.

Review article: dermatological complications of immunosuppressive and anti-TNF therapy in inflammatory bowel disease

BACKGROUND

With the expanding list of medications available to treat patients with inflammatory bowel disease (IBD), it is important to recognise adverse events, including those involving the skin. Dermatological adverse events may be confused with extra-intestinal manifestations of IBD.

AIM

To review drug-related dermatological manifestations associated with immunosuppressive and anti-tumour necrosis factor (anti-TNF) therapy.

METHODS

The literature was searched on PubMed for dermatological adverse events in IBD.

RESULTS

Present thiopurine exposure was associated with a 5.9-fold [95% confidence interval (CI), 2.1-16.4] increased risk of developing non-melanoma skin cancer (NMSC). The peak incidence is highest in Caucasians over the age of 65 years with crude incidence rates of 4.0 and 5.7/1000 patient-years for present and previous use. In anti-TNF-exposed subjects, drug-induced lupus was reported in 1% of the cases and a psoriatic rash in up to 3% of the cases. Anti-TNF monotherapy increases the risk of NMSC ~2-fold to a rate of 0.5 cases per 1000 person-years. Cutaneous lymphomas have been rarely reported in subjects on thiopurine or anti-TNF drug monotherapy. Combination therapy seems to have an additive effect on the risk of developing NMSC and lymphoma.

CONCLUSIONS

Physicians need to be aware of the wide spectrum of dermatological complications of immunosuppressive and anti-TNF therapy in IBD, especially psoriasis and non-melanoma skin cancer. Vigilance and regular screening for non-melanoma skin cancer is recommended. Case discussions between gastroenterologists and dermatologists should be undertaken to best manage dermatological adverse events.

Light on the horizont: biologicals in Behçet uveitis

Relapsing ocular involvement is one of the major manifestations in Behçet disease (BD). When ocular BD is left untreated, it often results in blindness in <5 years. Combining systemic corticosteroids with cyclosporine A and other conventional immune modulating agents has been the only choice for treatment. More recently, the introduction of 'biologics' seems to be an effective therapy in patients affected with BD, especially in those with ocular disease. Our purpose was to survey the current knowledge regarding the biological therapeutic approaches for Behçet uveitis. We focused on the most commonly used biological agents: 'tumor necrosis factor-alpha antagonists' and 'interferon alpha'. We attempted to compare the effectiveness of these two biologicals and tried to balance on the pros and cons of these agents in clinical practice. The impressive efficacy of both approaches in sight-threatening BD argues for their expanding role. Earlier introduction of these agents in the course of disease may prevent irreversible structural damage and may result in improved long-term prognosis.

Skin manifestations induced by TNF-alpha inhibitors in juvenile idiopathic arthritis

The tumor necrosis factor alpha (TNFα) inhibitors have been used with good clinical results in the treatment of juvenile idiopathic arthritis (JIA). Anti TNFα therapy is generally well tolerated. Besides the site injection reactions, other various cutaneous manifestations have been encountered as adverse events. Here, we report four young patients receiving treatment with anti-TNFα (infliximab, adalimumab, and etanercept) for JIA developing different skin manifestations more than 1 year after the initiation of therapy. They underwent a dermatological exam. All four patients were ACR-Ped 30 responders to anti-TNF drugs. The first patient developed cutaneous vasculitis, the second one had lichen planus manifestations, while the third and the fourth developed psoriatic palmoplantar pustulosis accompanied by plaque-type psoriasis localized to the scalp. None of the patients had a personal or family history of dermatological diseases. In the first two patients, skin lesions healed with topical treatment after the discontinuation of anti-TNF agent, while psoriatic lesions did not resolve despite discontinuation of the drug and dermatological treatment. TNF inhibition can be both anti-inflammatory and pro-inflammatory. Cutaneous manifestations could be considered as a paradoxical adverse event of the anti-TNF-alpha treatment not only in rheumatoid arthritis but also in juvenile idiopathic arthritis.

Pityriasis amiantacea: a distinctive presentation of psoriasis associated with tumour necrosis factor-α inhibitor therapy

Pityriasis amiantacea (PA; also known as tinea amiantacea) is a relatively rare but distinctive scalp condition characterized by thick scales that adhere to each other and to the hair shaft, resulting in agglomeration and matting of hair. Temporary alopecia is a common complication. Although a specific cause remains unclear, PA is associated with several inflammatory diseases such as psoriasis and seborrhoeic dermatitis. We present a case of PA as a complication of underlying psoriasis, which developed during tumour necrosis factor (TNF)-α inhibitor therapy for Crohn disease. This paradoxical cutaneous reaction to anti-TNF-α therapy has been recently described as an emerging and perplexing cause of psoriasis and psoriasiform eruptions.

Psoriasis and palmoplantar pustulosis associated with tumor necrosis factor-α inhibitors: the Mayo Clinic experience, 1998 to 2010

BACKGROUND

Tumor necrosis factor (TNF)-α antagonists have been associated with the induction of de novo or worsening psoriasis.

OBJECTIVE

We sought to retrospectively examine the clinical characteristics and outcomes of patients with psoriasis associated with anti-TNF-α therapy.

METHODS

We performed a retrospective review of patients with new-onset or worsening psoriasis during TNF-α inhibitor therapy between 1998 and 2010.

RESULTS

Of the 56 patients (mean age at psoriasis onset, 48.1 years), 41 (73%) were female. In all, 22 patients (39%) had Crohn's disease and 14 (25%) had rheumatoid arthritis. Thirty patients (54%) were treated with infliximab, 19 (34%) with adalimumab, and 7 (12%) with etanercept. New-onset or worsening psoriasis occurred after a mean treatment duration of 17.1 months. Plaque psoriasis (n = 27), palmoplantar pustulosis (n = 25), scalp psoriasis (n = 12), generalized pustular psoriasis (n = 7), erythrodermic psoriasis (n = 2), and inverse psoriasis (n = 2) were the cutaneous presentations. Among the 39 patients for whom full treatment response data were available, 33 (85%) had a complete or partial response; combined response rates (complete and partial) were slightly higher among those who discontinued anti-TNF-α therapy (16 of 17 patients [94%]) than among those who continued anti-TNF-α therapy (17 of 22 patients [77%]).

LIMITATIONS

Retrospective nature, possible referral bias, and lack of complete follow-up for some patients are limitations.

CONCLUSION

Although some patients sufficiently controlled their psoriasis while continuing anti-TNF-α therapy, those who discontinued therapy achieved higher rates of complete response. Further studies should explore the efficacy and safety of switching to an alternative anti-TNF-α agent.

Regression of Macular Cavernous Hemangioma with Systemic Infliximab

Cavernous hemangioma of the retina is an unusual vascular hamartoma that has been reported to occur either sporadically or as a dominantly inherited trait. A case of a large and sporadic macular cavernous hemangioma that was successfully treated with systemic infliximab as a first line of treatment is presented. The patient was referred with decreased vision of the right eye for 6 months. Fundus examination disclosed a reddish elevated lesion in the posterior pole that obscured the macula and encroached on the fovea. It consisted of grapelike aneurysms. The patient underwent treatment with infliximab intravenously. Two weeks after the second infusion of infliximab, visual acuity improved to 20/80 with a marked involution of the tumor in the right eye. Although the data are limited, we think that a new perspective for treatment of retinal vascular tumors may appear in the future considering antibodies to tumor necrosis factor (TNF)-alpha.

Infliximab stability after reconstitution, dilution, and storage under refrigeration

PURPOSE

The purpose of this study was to investigate the stability of reconstituted infliximab solutions and determine whether infliximab is suitable for compounding for potential intravitreal use.

METHODS

Infliximab was reconstituted, and the solution was aliquoted and stored refrigerated. On each day of testing, an aliquot was serially diluted to concentrations ranging from 50,000 pg/mL to 69 pg/mL. Each dilution was assayed by microsphere immunoassay daily for 5 days and weekly for a total of 6 weeks. The outcome measure was median fluorescence intensity measured by dual laser flow analysis of fluorochrome-labeled secondary antibodies to infliximab bound to tumor necrosis factor-alpha-coated microspheres.

RESULTS

There was an increasing median fluorescence intensity for increasing infliximab concentration in a sigmoidal dose-response curve with a variable slope that was equivalent for each time point. Each respective concentration of infliximab showed nearly equivalent median fluorescence intensity for every time point over the 6-week period.

CONCLUSION

The authors found that the immunoreactivity of 2 different concentrations of infliximab stored at 4 degrees C over a 6-week period remained stable. Infliximab is suitable for compounding and could be a cost-effective intravitreal medication for use in clinical practice if further study supports its safety and efficacy.

Immune-mediated skin lesions in patients treated with anti-tumour necrosis factor alpha inhibitors

OBJECTIVE

To describe immune-mediated skin lesion (IMSL) development in patients during anti-tumour necrosis factor (TNF) therapy.

METHODS

Two hundred and fifty-two patients with rheumatoid arthritis (RA) and 183 with spondyloarthropathies (SpA) treated with anti-TNF inhibitors were analysed to identify IMSLs.

RESULTS

Of the 252 patients with RA (146 treated with infliximab, 72 with adalimumab, and 34 with etanercept), 32 developed IMSLs. Eleven patients developed psoriatic skin lesions, 10 presented with granuloma annulare (GA), five had skin vasculitis, two alopecia areata, two discoid lupus erythematosus, one lichenoid eruption (lichen planus), and one vitiligo. Of the 183 patients with SpA (138 treated with infliximab, 37 with etanercept, and eight with adalimumab), 10 cases with IMSLs were identified. All were treated with infliximab. More specifically, six patients with ankylosing spondylitis (AS) developed psoriatic skin lesions, one developed GA, one lichen planus, and one alopecia areata. In addition, one patient with psoriatic arthritis (PsA) developed skin vasculitis. The occurrence of these IMSLs ranged from 3 to 36 months with a median of 20 months. Of all the patients with IMSL development, two with psoriatic skin lesions, two with GA, and one with vasculitis stopped anti-TNF therapy because of the extent and severity of the skin lesions.

CONCLUSIONS

Our results on patients treated with TNF antagonists strongly support a link between TNF inhibition and IMSL development. Although these clinical complications are rare, clinicians should be aware of their occurrence and should recognize them.

Decoy receptor 3 is highly expressed in patients with rheumatoid arthritis

Decoy receptor 3 (DcR3), a member of the tumor necrosis factor receptor (TNFR) superfamily, is a soluble receptor that binds to the TNF family including Fas ligand (Fas-L), LIGHT, and TL1A. DcR3 is mostly expressed in tumor cells and competitively inhibits the TNF family. We previously demonstrated that overexpressed DcR3 in rheumatoid synovial cells protects the cells from apoptosis in vitro. The objective of the study was to investigate DcR3 expression in serum and joint fluids of patients with rheumatoid arthritis (RA) and osteoarthritis (OA), and to analyze the correlations with disease activities and TNFalpha expression. Sera and joint fluids were collected from patients with RA and OA. Expression of DcR3 in sera and joint fluids was measured by ELISA. The concentration of DcR3 in sera and joint fluids of RA patients was significantly higher than that in sera and joint fluids of OA patients. A correlation between serum DcR3 concentration and disease activity was not observed, but the serum DcR3 concentration was strongly correlated with the TNFalpha concentration. DcR3 was highly expressed in serum and joint fluids of RA patients.

Cutaneous side effects of anti-tumor necrosis factor biologic therapy: a clinical review

BACKGROUND

Anti-tumor necrosis factor (anti-TNF) biologic agents have been associated with a number of adverse events.

OBJECTIVE

To review the cutaneous reactions that have been reported in patients receiving anti-TNF therapy.

METHODS

We performed a systematic MEDLINE search of relevant publications, including case reports and case series.

RESULTS

Reported cutaneous events included infusion and injection site reactions, psoriasiform eruptions, lupus-like disorders, vasculitis, granulomatous reactions, cutaneous infections, and cutaneous neoplasms. Infusion reactions and injection site reactions were definitely associated with anti-TNF administration, whereas all other events had a varying strength of association and severity, not necessarily requiring drug discontinuation.

LIMITATIONS

Most information was derived from spontaneous case reports, where ascertainment biases and frequency of reporting may impair detection methodology and causal relationships.

CONCLUSIONS

As anti-TNF biologic agents are progressively being used in clinical practice, cutaneous adverse events will be encountered more frequently. Until more data are accumulated with respect to their pathogenesis and potential association with anti-TNF therapy, dermatologists should become more familiar with the clinical presentation and management of such events.

Induction and exacerbation of psoriasis with TNF-blockade therapy: a review and analysis of 127 cases

BACKGROUND

There are reports of rare adverse effects of tumor necrosis factor (TNF) inhibitors, including infections, malignancies, and induction of autoimmune conditions. Intriguing, are cases of induction or exacerbation of psoriasis in conjunction with TNF inhibitor therapy, given that they are approved for treatment of the same condition.

OBJECTIVE

Published cases of psoriasis occurring during anti-TNF therapy were analyzed, including overviews of proposed etiologies and treatment recommendations.

METHODS

A literature search using Ovid MEDLINE and PubMed was performed for articles published between January 1990 and September 2007 to collect reported cases of psoriasis in patients receiving therapy with TNF blocking agents.

RESULTS

A total of 127 cases were identified: 70 in patients on infliximab (55.1%), 35 with etanercept (27.6%), and 22 with adalimumab (17.3%). Females comprised 58% of cases; mean age of reported patients was 45.8 years, and the time from initiation of treatment to onset of lesions averaged 10.5 months. These patients suffered from a number of primary conditions, with rheumatoid arthritis, ankylosing spondylitis, and Crohn's disease accounting for the vast majority. Palmoplantar pustular psoriasis was observed in 40.5% of the cases, with plaque-type psoriasis in 33.1%, and other types comprising the remainder. Topical corticosteroids were the most commonly employed treatment modality but led to resolution in only 26.8% of cases in which they were employed solely. Switching to a different anti-TNF agent led to resolution in 15.4% of cases. Cessation of anti-TNF therapy with systemic therapy led to resolution in 64.3% of cases.

CONCLUSION

More information and cases are needed. Biopsies of TNF-blockade-induced lesions may reveal what cytokines and cell types drive the development of these lesions. Additionally, there is a need to develop an algorithm to treat this paradoxical side effect of therapy with TNF-blockers.

[Biologic therapy of rheumatoid arthritis]

Rheumatoid arthritis (RA) and juvenile idiopathic/rheumatoid arthritis (JIA) are chronic, inflammatory, systemic, autoimmune diseases characterized by chronic arthritis leading to progressive joint erosions. The individual functional and social impact of rheumatoid arthritis is of great importance. Disability and joint damage occur rapidly and early in the course of the disease. The remarkably improved outcomes have been achieved initiating biologic therapy with close monitoring of disease progression. Biologic agents are drugs, usually proteins, which can influence chronic immune dysregulation resulting in chronic arthritis. According to the mechanism of action these drugs include: 1) anti-TNF drugs (etanercept, infiximab, adalimumab); 2) IL-1 blocking drugs (anakinra); 3) IL-6 blocking drugs (tocilizumab); 4) agents blocking selective co-stimulation modulation (abatacept); 5) CD 20 blocking drugs (rituximab). Biologics targeting TNF-alpha with methotrexate have revolutionized the treatment of RA, producing significant improvement in clinical, radiographic, and functional outcomes not seen previously. The new concept of rheumatoid arthritis treatment defines early diagnosis, early aggressive therapy with optimal doses of disease modifying antirheumatic drugs (DMARDs) and, if no improvement has been achieved during six months, early introduction of biologic drugs. The three-year experience of biologic therapy in Serbia has shown a positive effect on disease outcome.

Circulating levels of TNF-like cytokine 1A (TL1A) and its decoy receptor 3 (DcR3) in rheumatoid arthritis

TL1A is a novel TNF-like cytokine, which provides co-stimulatory and Th1-polarizing signals to activated lymphocytes, via binding to death-domain receptor 3 (DR3). These functions are inhibited when TL1A associates to decoy receptor 3 (DcR3). We investigated the serum expression of TL1A and DcR3 in 81 patients with RA and 51 healthy controls. TL1A concentrations were elevated in patients by 5-fold (P<0.00001). This increase was more prominent in RFactor-positive patients and correlated with clinical activity in this subgroup. DcR3 was detected more frequently and in significantly higher values in RA-derived sera, correlated strongly with TL1A, and was present in inflammatory synovial fluid. Severe RA stage was associated with highly elevated TL1A and DcR3 serum levels. Treatment with an anti-TNF agent significantly decreased TL1A serum levels. We conclude that TL1A may serve as an inflammatory marker in RA. Interactions between TL1A and its receptors may be important in the pathogenesis of RA.

Myelodysplasia and anemia of chronic disease in human tumor necrosis factor-alpha transgenic mice

TNF-alpha is a pleitropic cytokine that expresses both pro- and anti-inflammatory activity and transgenic mice expressing human tumor necrosis factor-alpha (TNF-alpha) exhibit a progressive polyarthritis that models rheumatoid arthritis (RA). One of the common comorbidities of RA is anemia of chronic disease (ACD). The purpose of these experiments was to study the changes in the bone marrow and peripheral blood that accompany polyarthritis in TNF-alpha transgenic mice in an effort to better understand the pathogenesis of myelodysplasia and ACD. Polychromatic cytometry, hematology and serum cytokine analysis were used to study the pathogenesis of ACD in human TNF-alpha transgenic mice. Our hematological evaluation revealed a mild, compensated, microcytic hypochromic anemia, and monocytosis. In the bone marrow, we observed alterations in cell kinetics, decreased relative expression of transferrin receptor and increased apoptosis and cell death in several late precursor cell populations. Although significant levels of human TNF-alpha were found in the serum, neither change in serum murine erythropoietin nor any significant difference observed in serum levels of murine IL-beta, IL-5, IL-6, IL-10, IL-12(p70), IL-17, TNF-alpha, IFNgamma, GM-CSF, MIP-1alphaJE, MCP-5 was observed. Tg197 mice develop a compensated, microcytic, hypochromic anemia, and a functional iron deficiency by 9 weeks of age. Changes in peripheral blood are reflected in alterations in cell kinetics, transferrin receptor expression and markedly increased apoptosis and cell death in the bone marrow indicating that TNF-alpha may contribute to myelodysplasia in ACD. Moreover, since human TNF-alpha can interact only with murine TNFR1, our data suggest that TNFR1 may play an important role in the development of ACD.

Osteoclast precursor interaction with bone matrix induces osteoclast formation directly by an interleukin-1-mediated autocrine mechanism

Interleukin-1 (IL-1) and tumor necrosis factor (TNF) mediate bone resorption in a variety of diseases affecting bone. Like TNF, IL-1 is secreted by osteoclast precursors (OCPs), but unlike TNF, it does not induce osteoclast formation directly from OCPs in vitro. TNF induces IL-1 expression and activates c-Fos, a transcription factor required in OCPs for osteoclast formation. Here, we examined whether IL-1 can induce osteoclast formation directly from OCPs overexpressing c-Fos and whether interaction with bone matrix affects OCP cytokine expression. We infected OCPs with c-Fos or green fluorescent protein retrovirus, cultured them with macrophage colony-stimulating factor and IL-1 on bone slices or plastic dishes, and assessed osteoclast and resorption pit formation and expression of IL-1 by OCPs. We used a Transwell assay to determine whether OCPs secrete IL-1 when they interact with bone matrix. IL-1 induced osteoclast formation directly from c-Fos-expressing OCPs on plastic. c-Fos-expressing OCPs formed osteoclasts spontaneously on bone slices without addition of cytokines. OCPs on bone secreted IL-1, which induced osteoclast formation from c-Fos-expressing OCPs in the lower Transwell dishes. The bone matrix proteins dentin sialoprotein and osteopontin, but not transforming growth factor-beta, stimulated OCP expression of IL-1 and induced c-Fos-expressing OCP differentiation into osteoclasts. Osteoclasts eroding inflamed joints have higher c-Fos expression compared with osteoclasts inside bone. We conclude that OCPs expressing c-Fos may induce their differentiation directly into osteoclasts by an autocrine mechanism in which they produce IL-1 through interaction with bone matrix. TNF could induce c-Fos expression in OCPs at sites of inflammation in bone to promote this autocrine mechanism and thus amplify bone loss.

Alopecia areata universalis elicited during treatment with adalimumab

Adalimumab is a fully humanized recombinant anti-tumour-necrosis-factor (TNF-alpha) monoclonal antibody which has been approved for rheumatoid arthritis, active ankylosing spondylitis, psoriatic arthritis and Crohn's disease. We report a case of alopecia areata (AA) universalis occurring 6 months after administration of adalimumab monotherapy in a patient with a long-standing history of psoriatic arthritis and psoriasis. The diagnosis was confirmed by a scalp biopsy which showed a peribulbar infiltrate of both CD4+ and CD8+ T cells, CD1a+ dendritic cells as well as CD68+ and CD163+ macrophages. In addition, immunofluorescence staining for TNF-alpha was found in the mononuclear cell infiltrate. This case suggests a complex role of TNF-alpha in the induction of AA.

Tumor necrosis factor antagonists: preliminary evidence for an emerging approach in the treatment of ocular inflammation

The anti-tumor necrosis factor (TNF) monoclonal antibody infliximab and the soluble TNF receptor etanercept inhibit the pleiotropic actions of TNF and are widely used for the treatment of rheumatoid arthritis (RA), juvenile idiopathic arthritis (JIA), spondyloarthropathies (SpA), Crohn's disease, and psoriasis with an acceptable safety profile. A pathogenetic role of TNF in ocular inflammatory conditions has recently emerged from small trials reporting preliminary results on the efficacy of these agents in patients with noninfectious uveitis, regardless of the origin of the disease. The authors review the published experience, derived mostly from investigator-sponsored trials and uncontrolled case series, on the use of TNF antagonists in approximately 280 patients with various ocular conditions who were inadequately controlled on currently available therapy. These reports suggest that TNF antagonists, mainly infliximab, which may have better efficacy than etanercept, are useful in the treatment of ocular inflammation associated with Adamantiades-Behçet's disease, RA, JIA, SpA, Crohn's, sarcoidosis, and Graves' disease ophthalmopathy. Infliximab was also beneficial in small numbers of patients with idiopathic uveitis or scleritis, birdshot retinochoroiditis, uveitic and diabetic cystoid macular edema, and age-related macular degeneration. The currently available data are nonrandomized and thus preliminary, providing the foundation and justification for randomized trials to assess efficacy and safety. Until such results are available, knowledge regarding the use of anti-TNF regimens in ophthalmology is incomplete. However, the preliminary evidence points to a growing optimism for targeting TNF in patients with ocular inflammation.

Rheumatoid arthritis in dermatology

Rheumatoid arthritis (RA) is a chronic progressive disorder characterized by symmetric inflammatory arthritis in association with systemic symptoms. Although considered a "joint disease," RA is associated with involvement in diverse organ systems, including the skin. Common manifestations include Raynaud phenomenon, rheumatoid nodules, and rheumatoid vasculitis. As with other extra-articular manifestations, dermatologic involvement tends to occur in patients with more severe RA. In addition to manifestations related to the disease, there are also sundry dermatologic reactions related to the medications used to treat RA. Understanding the etiology and therapy for cutaneous manifestations of RA will help optimize patient care.

Transmembrane TNF protects mutant mice against intracellular bacterial infections, chronic inflammation and autoimmunity

Using targeted mutagenesis in mice, we have blocked shedding of endogenous murine TNF by deleting its cleavage site. Mutant mice produce physiologically regulated levels of transmembrane TNF (tmTNF), which suffice to support thymocyte proliferation but cannot substitute for the hepatotoxic activities of wild-type TNF following LPS/D-galactosamine challenge in vivo and are not sufficient to support secondary lymphoid organ structure and function. Notably, however, tmTNF is capable of exerting anti-Listerial host defenses while remaining inadequate to mediate arthritogenic functions, as tested in the tristetraprolin-deficient model of TNF-dependent arthritis. Most interestingly, in the EAE model of autoimmune demyelination, tmTNF suppresses disease onset and progression and retains the autoimmune suppressive properties of wild-type TNF. Together, these results indicate that tmTNF preserves a subset of the beneficial activities of TNF while lacking detrimental effects. These data support the hypothesis that selective targeting of soluble TNF may offer several advantages over complete blockade of TNF in the treatment of chronic inflammation and autoimmunity.

Spondyloarthropathy: disease at the crossroads of immunity

Up until recently, the prevailing paradigm relating to spondyloarthropathy (SpA) pathogenesis was that they were human leukocyte antigen (HLA)-associated, T-cell-driven autoimmune diseases. This view is now being questioned. Careful studies of well-characterised cohorts of patients with SpA, including detailed analysis of involved tissue, together with clinical trials of targeted treatments, in particular anti-tumour necrosis factor (TNF) therapies, have contributed enormously to both interest in and understanding of disease pathogenesis. In this chapter, our current knowledge and understanding of the relative contributions of the components of the innate and adaptive arms of the immune response to SpA pathogenesis is reviewed. It is clear that both arms of the immune response are involved and inter-dependent in SpA. With continued emphasis on discovery research, including detailed analysis of novel therapeutic interventions, significant additional breakthroughs in SpA are likely to be forthcoming.

The Response of Human Epithelial Cells to TNF Involves an Inducible Autocrine Cascade

Tumor necrosis factor (TNF) is a proinflammatory cytokine that induces conflicting pro- and antiapoptotic signals whose relative strengths determine the extent of cell death. TNF receptor (TNFR) has been studied in considerable detail, but it is not known how crosstalk among antagonistic pro- and antiapoptotic signals is achieved. Here we report an experimental and computational analysis of crosstalk between prodeath TNF and prosurvival growth factors in human epithelial cells. By applying classifier-based regression to a cytokine-signaling compendium of approximately 8000 intracellular protein measurements, we demonstrate that cells respond to TNF both directly, via activated TNF receptor, and indirectly, via the sequential release of transforming growth factor-alpha (TGF-alpha), interleukin-1alpha (IL-1alpha), and IL-1 receptor antagonist (IL-1ra). We refer to the contingent and time-varying series of extracellular signals induced by TNF as an "autocrine cascade." Time-dependent crosstalk of synergistic and antagonistic autocrine circuits may serve to link cellular responses to the local environment.

Botanical immunodrugs: scope and opportunities

Modulation of the immune system can be addressed through a variety of specific and non-specific approaches. Many agents of synthetic and natural origin have stimulatory, suppressive or regulatory activity. There is growing evidence that drugs or biological agents capable of modulating single pathways or targets are of limited value as immune-related therapies. Systems biology approaches are now gaining more interest compared with monovalent approaches, which can be of limited benefits with complications. This has stimulated interest in the use of 'cocktails' of immunodrugs to restore immunostasis. Botanicals are chemically complex and diverse and could therefore provide appropriate combinations of synergistic moieties useful in drug discovery. Here, the importance of traditional medicine in natural product drug discovery related to immunodrugs is reviewed.

Regression of neovascular age-related macular degeneration following infliximab therapy

PURPOSE

To describe the effects of the antitumor necrosis factor (TNF) monoclonal antibody Infliximab systemic therapy on choroidal neovacularisation (CNV) secondary to age-related macular degeneration (AMD).

DESIGN

Prospective, noncomparative series of three patients.

METHODS

A subretinal membrane secondary to AMD was documented by fluoroangiography at baseline in three elderly patients scheduled to receive Infliximab therapy for inflammatory arthritis (infusions of 5 mg/kg at weeks 0, 2, 6, and every 8 weeks thereafter). Follow-up was performed at three months post-baseline, as well as during 18 months of continuing treatment in the first patient.

RESULTS

CNV regressed partially at three months and resolved at six months in the first patient. Best-corrected visual acuity (BCVA) increased from 0.05 to 0.2; this effect was sustained at 18 months. Regression of subretinal membrane and increase of BCVA was also documented in the other patients. No ocular or extra-ocular side effects were noted.

CONCLUSIONS

These findings suggest a plausible pathogenetic role of TNF in CNV secondary to AMD. Additional patients should be studied to confirm the promising clinical results.

Psoriasis induced by anti-tumor necrosis factor therapy: A paradoxical adverse reaction

Administration of anti-tumor necrosis factor (anti-TNF) agents is beneficial in a variety of chronic inflammatory conditions, including psoriasis. We describe 5 patients in whom psoriasiform skin lesions developed 6-9 months after the initiation of anti-TNF therapy for longstanding, seropositive rheumatoid arthritis (etanercept or adalimumab), typical ankylosing spondylitis (infliximab), and Adamantiades-Behçet's disease (infliximab). In all 5 patients, the underlying disease had responded well to anti-TNF therapy. Four patients developed a striking pustular eruption on the palms and/or soles accompanied by plaque-type psoriasis at other skin sites, while 1 patient developed thick erythematous scaly plaques localized to the scalp. In 3 patients there was nail involvement with onycholysis, yellow discoloration, and subungual keratosis. Histologic findings from skin biopsies were consistent with psoriasis. None of these patients had a personal or family history of psoriasis. In all patients, skin lesions subsided either with topical treatment alone, or after discontinuation of the responsible anti-TNF agent. The interpretation of this paradoxical side effect of anti-TNF therapy remains unclear but may relate to altered immunity induced by the inhibition of TNF activity in predisposed individuals.

Discoid lupus erythematosus-like eruption induced by infliximab

Lupus erythematosus-like syndromes have been reported as an adverse effect of anti-tumour necrosis factor-alpha therapy. We report the case of a patient with rheumatoid arthritis who developed a discoid lupus erythematosus-like eruption after treatment with infliximab. The rash consisted of diffuse scaly erythematous plaques on the face, trunk and extremities, and occurred in the context of elevated anti-nuclear and anti-double-stranded DNA antibody titres. Direct immunofluorescence of lesional skin showed linear deposition of IgG, IgM and C3. The lesions resolved completely after the discontinuation of infliximab and with the use of anti-malarial therapy. We discuss the clinical, histological and immunohistochemical features of this case and review the literature with respect to the incidence of lupus erythematosus-like syndromes in patients receiving tumour necrosis factor-alpha antagonists.

Attenuation of inflammatory polyarthritis in TNF transgenic mice by diacerein: comparative analysis with dexamethasone, methotrexate and anti-TNF protocols

The impact of diacerein, an effective cartilage targeted therapy that is used in patients with osteoarthritis, on the development and progression of chronic inflammatory arthritis was evaluated in a tumor necrosis factor (TNF) transgenic mouse model (Tg197). The response to diacerein at 2, 20, or 60 mg/kg daily, as well as the comparative effects of other antiarthritis drugs including dexamethasone (0.5 mg/kg daily), methotrexate (1 mg/kg three times weekly) and an anti-TNF agent (5 mg/kg weekly), were assessed in the Tg197 mice. Treatment was initiated before the onset of arthritis and was continued for 5 weeks. A significant improvement in clinical symptoms was found in all three diacerein treated groups in comparison with untreated groups. Confirming these data, semiquantitative histopathologic analysis of the hind paws revealed a significant reduction not only in cartilage destruction but also in the extent of synovitis and bone erosion in diacerein treated groups in comparison with untreated groups. At the most effective dose tested (2 mg/kg daily), diacerein inhibited the onset of arthritis in 28% and attenuated the progression of arthritis in 35% of the Tg197 mice. Comparative analyses showed diacerein to be more potent than methotrexate but not as effective as dexamethasone or anti-TNF agents in suppressing the progression of the TNF mediated arthritis in this model. These results indicate that diacerein has a disease modifying effect on the onset and progression of TNF driven chronic inflammatory arthritis, suggesting that the prophylactic or therapeutic potential of diacerein in patients with RA should be further examined.