Inhibition of immunoreactive tumor necrosis factor-alpha by a chimeric antibody in patients infected with human immunodeficiency virus type 1

A Review of the Use of Biological Agents in Human Immunodeficiency Virus Positive Patients With Rheumatological Diseases

After approval, initial biologics etanercept, infliximab, and adalimumab became useful in the therapeutic armamentarium to treat rheumatoid arthritis (RA) patients who had an inadequate response to disease-modifying anti-rheumatic drugs (DMARDs). However, all phase-III clinical trials submitted to the FDA, by design, excluded patients who were human immunodeficiency virus (HIV) positive. They are another subset of patients with low immunity due to their HIV-positive status. Very little information is available about the use of biologics in this new group of patients if they fail to respond to DMARDS. The available literature is limited to case reports about HIV-positive RA patients with reported side effects. These side effects range from no opportunistic infections (OIs) in some to acute respiratory distress syndrome (ARDS) and disseminated intravascular coagulopathy (DIC) reported in others. Some HIV cases may initially present with rheumatological manifestations. With growing epidemiologic evidence of frequent joint manifestations in HIV-positive patients, HIV testing should be done more frequently in patients with RA, even those who deny risk factors for HIV. This review may help develop future guidelines on how to manage HIV-positive RA patients.

Remicade® (infliximab): 20 years of contributions to science and medicine

On August 24, 1998, Remicade^® (infliximab), the first tumor necrosis factor-α (TNF) inhibitor, received its initial marketing approval from the US Food and Drug Administration for the treatment of Crohn’s disease. Subsequently, Remicade was approved in another five adult and two pediatric indications both in the USA and across the globe. In the 20 years since this first approval, Remicade has made several important contributions to the advancement of science and medicine: 1) clinical trials with Remicade established the proof of concept that targeted therapy can be effective in immune-mediated inflammatory diseases; 2) as the first monoclonal antibody approved for use in a chronic condition, Remicade helped in identifying methods of administering large, foreign proteins repeatedly while limiting the body’s immune response to them; 3) the need to establish Remicade’s safety profile required developing new methods and setting new standards for postmarketing safety studies, specifically in the real-world setting, in terms of approach, size, and duration of follow-up; 4) the study of Remicade has improved our understanding of TNF’s role in the immune system, as well as our understanding of the pathophysiology of a range of diseases characterized by chronic inflammation; and 5) Remicade and other TNF inhibitors have transformed treatment practices in these chronic inflammatory diseases: remission has become a realistic goal of therapy and long-term disability resulting from structural damage can be prevented. This paper reviews how, over the course of its development and 20 years of use in clinical practice, Remicade was able to make these contributions.

2018 update of the APLAR recommendations for treatment of rheumatoid arthritis

AIM

To update recommendations based on current best evidence concerning the treatment of rheumatoid arthritis (RA), focusing particularly on the role of targeted therapies, to inform clinicians on new developments that will impact their current practice.

MATERIALS AND METHODS

A search of relevant literature from 2014 to 2016 concerning targeted therapies in RA was conducted. The RA Update Working Group evaluated the evidence and proposed updated recommendations using the Grading of Recommendations, Assessment, Development and Evaluations (GRADE) approach, to describe the quality of evidence and strength of recommendations. Recommendations were finalized through consensus using the Delphi technique.

RESULTS

This update provides 16 RA treatment recommendations based on current best evidence and expert clinical opinion. Recommendations 1-3 deal with the use of conventional synthetic disease-modifying antirheumatic drugs. The next three recommendations (4-6) cover the need for screening and management of infections and comorbid conditions prior to starting targeted therapy, while the following seven recommendations focus on use of these agents. We address choice of targeted therapy, switch, tapering and discontinuation. The last three recommendations elaborate on targeted therapy for RA in special situations such as pregnancy, cancer, and major surgery.

CONCLUSION

Rheumatoid arthritis remains a significant health problem in the Asia-Pacific region. Patients with RA can benefit from the availability of effective targeted therapies, and these updated recommendations provide clinicians with guidance on their use.

Assessment and management of musculoskeletal disorders among patients living with HIV

HIV is a global pandemic. However, anti-retroviral therapy has transformed the prognosis and, providing compliance is good, a normal life expectancy can be anticipated. This has led to increasing numbers of people with chronic prevalent, treated infection living to older ages. Musculoskeletal pain is commonly reported by HIV patients and, with resumption of near-normal immune function, HIV-infected patients develop inflammatory rheumatic diseases that require assessment and management in rheumatology clinics. Moreover, it is becoming apparent that avascular necrosis and osteoporosis are common comorbidities of HIV. This review will contextualize the prevalence of musculoskeletal symptoms in HIV, informed by data from a UK-based clinic, and will discuss the management of active inflammatory rheumatic diseases among HIV-infected patients taking anti-retroviral therapy, highlighting known drug interactions.

Rates of Serious Infections in HIV-Infected Patients Receiving Tumor Necrosis Factor Inhibitor Therapy for Concomitant Autoimmune Diseases

OBJECTIVE

To estimate the incidence of serious infections in patients with HIV infection and autoimmune disease who were treated with tumor necrosis factor (TNF) inhibitors, and to compare these rates by stratified viral load levels.

METHODS

Using a unified search strategy, 4 centers identified HIV-infected patients exposed to TNF inhibitors. Patient characteristics and infection data were assessed via chart review in all patients who were ≥18 years old and who received TNF inhibitor therapy after HIV diagnosis, between January 1999 and March 2015.

RESULTS

We studied 23 patients with 26 uses of TNF inhibitor therapy (86.7 person-years of followup). Two (8.7%) experienced at least 1 serious infection episode, for an overall incidence rate of 2.55 per 100 patient-years (95% confidence interval [95% CI] 0.28-9.23). The incidence rate per 100 patient-years was 3.28 (95% CI 0.04-18.26) among patients with a viral load >500 copies/ml at therapy initiation and 2.09 (0.03-11.65) among patients with a viral load ≤500 copies/ml.

CONCLUSION

This study suggests that the rate of serious infections in patients with HIV infection under active care who have received treatment with TNF inhibitors may be comparable to the rates observed in registry databases.

Targeting TNF and TNF Receptor Pathway in HIV-1 Infection: from Immune Activation to Viral Reservoirs

Several cellular functions such as apoptosis, cellular proliferation, inflammation, and immune regulation involve the tumor necrosis factor-α (TNF)/TNF receptor (TNFR) pathway. Human immunodeficiency virus 1 (HIV-1) interacts with the TNF/TNFR pathway. The activation of the TNF/TNFR pathway impacts HIV-1 replication, and the TNF/TNFR pathway is the target of HIV-1 proteins. A hallmark of HIV-1 infection is immune activation and inflammation with increased levels of TNF in the plasma and the tissues. Therefore, the control of the TNF/TNFR pathway by new therapeutic approaches could participate in the control of immune activation and impact both viral replication and viral persistence. In this review, we will describe the intricate interplay between HIV-1 proteins and TNF/TNFR signaling and how TNF/TNFR activation modulates HIV-1 replication and discuss new therapeutic approaches, especially anti-TNF therapy, that could control this pathway and ultimately favor the clearance of infected cells to cure HIV-infected patients.

Use of etanercept to treat rheumatoid arthritis in an HIV-positive patient: a case-based review

Rheumatoid arthritis (RA) is a relatively common autoimmune disease that is associated with progressive disability and systemic complications, with a relatively high socioeconomic burden. The treatment of RA has been revolutionized by the use of biological drugs, such as anti-tumor necrosis factor (TNF) agents. A wide spectrum of RA disease severity has been reported among patients with human immunodeficiency virus (HIV) infection. Yet, only a few cases using anti-TNF therapy have been described in this clinical population. Therefore, the aim of our case-based review was to describe the successful use of etanercept in a 38-year-old female patient with RA concomitant with HIV infection, who had been resistant to the first-line anti-rheumatic therapies. As per routine care guidelines, the patient was screened for hepatitis virus infection, latent tuberculosis, and other infectious conditions, prior to the initiation of etanercept treatment. CD4 cell count, HIV viral load, and adverse effects were closely monitored during the treatment. The HIV infection remained stable with etanercept treatment, without the need for anti-retrovirus agents. No adverse effects and serious infections were identified during the treatment. Therefore, anti-TNF therapy is a viable alternative for the treatment of RA in patients with HIV, who do not respond to conventional anti-rheumatic therapies. The relationship between TNF-α and HIV infection, as well as cautionary guidelines regarding the utilization of anti-TNF therapy in this clinical population, is discussed.

Use of tumor necrosis factor (TNF) inhibitors in patients with HIV/AIDS

Patients with HIV and AIDS are living longer because of advancements in antiretroviral therapy. These patients are often susceptible to debilitating inflammatory disorders that are refractory to standard treatment. We discuss the relationship of tumor necrosis factor-alpha and HIV and then review 27 published cases of patients with HIV being treated with tumor necrosis factor-alpha inhibitors. This review is limited because no randomized controlled trials have been performed with this patient population. Regardless, we propose that reliable seropositive patients, who are adherent to medication regimens and frequent monitoring and have failed other treatment modalities, should be considered for treatment with tumor necrosis factor-alpha inhibitors.

Treatment of severe non-infectious uveitis in high-risk conditions (Part 2): systemic infections; management and safety issues

INTRODUCTION

Management of patients with severe immune-mediated uveitis requires the use of immunosuppressive (IS) drugs in selected cases. This may be particularly challenging in certain patients with associated conditions, which may increase the risk of side effects or modify guidelines for the use of such drugs. Chronic viral and mycobacterial infections in the setting of non-infectious uveitis create a number of diagnostic but also therapeutic dilemmas to clinicians because they can be exacerbated by IS therapies with detrimental effects.

AREAS COVERED

In this review, we will focus on very specific chronic infections that can be affected by IS therapies: human immunodeficiency virus infection, chronic hepatitis virus infection and tuberculosis. The main aim of this review is to provide an updated and comprehensive practical guide for practitioners regarding the therapeutic decision-making and management of patients with non-infectious uveitis affected by the aforementioned infectious conditions.

EXPERT OPINION

Clinicians should be aware of the risk of viral and mycobacterial reactivation of an underlying infection during IS therapy. However, most of these conditions do not represent an absolute contraindication if one were able to apply an appropriate prior screening and close monitoring of such therapy.

Review article: the intersection of mucosal pathophysiology in HIV and inflammatory bowel disease, and its implications for therapy

BACKGROUND

The immunopathology of inflammatory bowel diseases (IBD) and HIV in the gastrointestinal (GI) tract can be viewed as ends of a spectrum with IBD being associated with 'immune excess' and HIV with 'immune paucity' within the GI tract.

AIM

To review the pathophysiology of IBD and HIV as they intersect in the gut immune system.

METHODS

A search was conducted in PubMed using defined keywords 'IBD, inflammatory bowel disease, Crohn's disease, ulcerative colitis, HIV, innate immunity, mucosal layer, macrophage, cytokine, dendritic cells, adaptive immunity, CD4, T cells, Th1, Th2, natural killer T cells (NKT)'.

RESULTS

Both the mucosal innate defence and adaptive immunity are profoundly affected by IBD and HIV. The pathophysiology of IBD and HIV with regard to mucosal barrier, macrophages, dendritic cells, NK cells, NKT cells and T-cell subsets is distinct yet closely interwoven. There is limited information on the clinical manifestations of patients who have both IBD and HIV. However, recent studies suggest that the clinical course of IBD may be attenuated by concurrent HIV infection - a premise that is reasonably supported by what is known of their pathophysiology.

CONCLUSIONS

It is apparent that through specific pathophysiological mechanisms, HIV is capable of attenuating inflammation in IBD. In the absence of experimental models, further clinical studies are necessary to better understand patients with concurrent disease and decipher the clinical and mechanistic relationship between HIV and IBD at mucosal surfaces. Such studies are critical to guide therapeutic decisions in the management of patients with IBD infected with HIV.

TNF and TNF receptor superfamily members in HIV infection: new cellular targets for therapy?

Tumor necrosis factor (TNF) and TNF receptors (TNFR) superfamily members are engaged in diverse cellular phenomena such as cellular proliferation, morphogenesis, apoptosis, inflammation, and immune regulation. Their role in regulating viral infections has been well documented. Viruses have evolved with numerous strategies to interfere with TNF-mediated signaling indicating the importance of TNF and TNFR superfamily in viral pathogenesis. Recent research reports suggest that TNF and TNFRs play an important role in the pathogenesis of HIV. TNFR signaling modulates HIV replication and HIV proteins interfere with TNF/TNFR pathways. Since immune activation and inflammation are the hallmark of HIV infection, the use of TNF inhibitors can have significant impact on HIV disease progression. In this review, we will describe how HIV infection is modulated by signaling mediated through members of TNF and TNFR superfamily and in turn how these latter could be targeted by HIV proteins. Finally, we will discuss the emerging therapeutics options based on modulation of TNF activity that could ultimately lead to the cure of HIV-infected patients.

Clinical use of anti-TNF therapy and increased risk of infections

Biologics such as antitumor necrosis factor (anti-TNF) drugs have emerged as important agents in the treatment of many chronic inflammatory diseases, especially in cases refractory to conventional treatment modalities. However, opportunistic infections have become a major safety concern in patients on anti-TNF therapy, and physicians who utilize these agents must understand the increased risks of infection. A literature review of the published data on the risk of bacterial, viral, fungal, and parasitic infections associated with anti-TNF therapy was performed and the clinical presentation, diagnostic tests, management, and prevention of opportunistic infections in patients receiving anti-TNF therapy were reviewed. Awareness of the therapeutic potential and associated adverse events is necessary for maximizing therapeutic benefits while minimizing adverse effects from anti-TNF treatments. Patients should be adequately vaccinated when possible and closely monitored for early signs of infection. When serious infections occur, withdrawal of anti-TNF therapy may be necessary until the infection has been identified and properly treated.

Reduced inflammation and lymphoid tissue immunopathology in rhesus macaques receiving anti-tumor necrosis factor treatment during primary simian immunodeficiency virus infection

BACKGROUND

Human immunodeficiency virus (HIV) and simian immunodeficiency virus (SIV) infections induce robust, generalized inflammatory responses that begin during acute infection and lead to pathological systemic immune activation, fibrotic damage of lymphoid tissues, and CD4⁺ T-cell loss, pathogenic processes that contribute to disease progression.

METHODS

To better understand the contribution of tumor necrosis factor (TNF), a key regulator of acute inflammation, to lentiviral pathogenesis, rhesus macaques newly infected with SIVmac239 were treated for 12 weeks in a pilot study with adalimumab (Humira), a human anti-TNF monoclonal antibody.

RESULTS

Adalimumab did not affect plasma SIV RNA levels or measures of T-cell immune activation (CD38 or Ki67) in peripheral blood or lymph node T cells. However, compared with untreated rhesus macaques, adalimumab-treated rhesus macaques showed attenuated expression of proinflammatory genes, decreased infiltration of polymorphonuclear cells into the T-cell zone of lymphoid tissues, and weaker antiinflammatory regulatory responses to SIV infection (ie, fewer presumed alternatively activated [ie, CD163⁺] macrophages, interleukin 10-producing cells, and transforming growth factor β-producing cells), along with reduced lymphoid tissue fibrosis and better preservation of CD4⁺ T cells.

CONCLUSIONS

While HIV/SIV replication drives pathogenesis, these data emphasize the contribution of the inflammatory response to lentiviral infection to overall pathogenesis, and they suggest that early modulation of the inflammatory response may help attenuate disease progression.

Tumor necrosis factor blockade and the risk of viral infection

Tumor necrosis factor (TNF) blockers are widely used to treat rheumatoid arthritis and other chronic inflammatory diseases. Many studies have demonstrated an increased risk of opportunistic infections such as tuberculosis and fungal infection in patients treated with TNF blockers, which is thought to be related to the primary role of TNF both in host defense and in the immune response. Little is known, however, about the association between TNF blockade and the development of viral infection. Owing to the critical role of TNF in the control of viral infection, depletion of this cytokine with TNF blockers could facilitate the development or reactivation of viral infection. A number of large observational studies have found an increased risk of herpes zoster in patients receiving TNF blockers for the treatment of rheumatoid arthritis. This Review draws attention to the risk of several viral infections, including HIV, varicella zoster virus, Epstein-Barr virus, cytomegalovirus, and human papillomavirus, in patients receiving TNF-blocking therapy for chronic inflammatory conditions. In addition, implications for clinical practice and possible preventative approaches are discussed.

Review article: chronic viral infection in the anti-tumour necrosis factor therapy era in inflammatory bowel disease

BACKGROUND

Anti-tumour necrosis factor (TNF) therapy is now well established in the treatment of inflammatory bowel disease and the risk of opportunistic infection is recognized. However, specific considerations regarding screening, detection, prevention and treatment of chronic viral infections in the context of anti-TNF therapy in inflammatory bowel disease are not widely adopted in practice.

AIM

To provide a detailed and comprehensive review of the relevance of chronic viral infections in the context of anti-TNF therapy in inflammatory bowel disease.

METHODS

Literature search was conducted using Medline, Pubmed and Embase using the terms viral infection, hepatitis, herpes, CMV, EBV, HPV, anti-TNF, infliximab, adalimumab, certolizumab pegol and etanercept. Hepatitis B and C and HIV had the largest literature associated and these have been summarized in Tables.

RESULTS

Particular risks are associated with the use of anti-TNF drugs in patients with hepatitis B infection, in whom reactivation is common unless anti-viral prophylaxis is used. Reactivation of herpes zoster is the most common viral problem associated with anti-TNF treatment, and may be particularly severe. Primary varicella infection may present with atypical features in patients on anti-TNF.

CONCLUSION

Appreciation of risks of chronic viral disease associated with anti-TNF therapy may permit early recognition, prophylaxis and treatment.

Infliximab therapy for HIV positive Crohn's disease: A case report

Anti-TNF-alpha is now established as a major player in the treatment of Crohn's disease, however the use of anti-TNF-alpha therapy in patients concomitantly having HIV infection and Crohn's disease is a relatively unexplored subject. There is generally some apprehension and anxiety to use infliximab in patients with HIV. One case has been reported in literature of usage of anti-TNF-alpha in HIV positive patient with Crohn's disease who was on anti-retroviral therapy. We report for the first time the successful usage of infliximab in treating Crohn's disease in an HIV positive patient who is not on any anti-retroviral treatment.

Incidence and nature of infectious disease in patients treated with anti-TNF agents

Tumor necrosis factor alpha (TNF-alpha) inhibitors offer a targeted therapeutic strategy that contrasts with the nonspecific immunosuppressive agents traditionally used to treat most inflammatory diseases. These biologic agents have had a significant impact in ameliorating the signs and symptoms of inflammatory rheumatoid disease and improving patient function. From the onset of clinical trials, a central concern of cytokine blockade has been a potential increase in susceptibility to infections. Not surprisingly, a variety of infections have been reported in association with the use of TNF-alpha inhibitor agents. In particular, there is evidence suggesting an increased rate of granulomatous infections in patients treated with monoclonal TNF-alpha inhibitors. This review provides the incidence and nature of infections in patients treated with TNF-alpha inhibitor agents and reminds the clinician of the required vigilance in monitoring patients.

The implications of anti-tumour necrosis factor therapy for viral infection in patients with inflammatory bowel disease

INTRODUCTION

Anti-tumour necrosis factor (TNF) therapy is increasingly used in the management of inflammatory bowel disease; however, concerns have been raised regarding risk of infection with such drugs. Little is known about their effect upon viral infection.

SOURCES OF DATA

A search of PubMed using the terms 'infliximab', 'etanercept', 'adalimumab' or 'anti-TNF therapy' combined with the names of specific viruses was performed. A search of cited papers was used to identify further relevant reports.

AREAS OF AGREEMENT

Numerous reports of the use of anti-TNF in patients with chronic or latent viral infection appear in the literature. Specific problems related to hepatitis B virus and varicella zoster virus may exist. The safety profile of anti-TNF in chronic viral infection is generally reassuring.

AREAS OF CONTROVERSY

Numerous consensus statements relating to pre-treatment serology or vaccination have recently appeared; however, significant variation exists in their recommendations.

GROWING POINTS

Increasing awareness of the implications of anti-TNF therapy on viral infection may allow safer use of such drugs.

AREAS TIMELY FOR DEVELOPING RESEARCH

The clinical and cost-effectiveness of screening for viral infections prior to anti-TNF requires further study.

Rheumatic conditions in human immunodeficiency virus infection

Many rheumatic diseases have been observed in HIV-infected persons. We, therefore, conducted a comprehensive literature search in order to review the prevalence, presentation and pathogenesis of rheumatic manifestations in HIV-infected subjects. Articular conditions (arthralgia, arthritis and SpAs) are either caused by the HIV infection itself, triggered by adaptive changes in the immune system, or secondary to microbial infections. Muscular symptoms may result from rhabdomyolysis, myositis or from side-effects of highly active anti-retroviral therapy (HAART). Osseous complications include osteonecrosis, osteoporosis and osteomyelitis. Some conditions such as the diffuse infiltrative lymphocytosis syndrome and sarcoidosis affect multiple organ systems. SLE may be observed but may be difficult to differentiate from HIV infection. Some anti-retroviral agents can precipitate hyperuricaemia and are associated with arthralgia. When indicated, immunosuppressants and even anti-TNF-alpha agents can be used in the carefully monitored HIV patient. Thus, rheumatic diseases and asymptomatic immune phenomena remain prevalent in HIV-infected persons even after the widespread implementation of highly active anti-retroviral therapy.

Problems encountered during anti-tumour necrosis factor therapy

Worldwide, over 400,000 patients have been treated with tumour necrosis factor (TNF)-alpha antagonists for indications that include rheumatoid arthritis, juvenile rheumatoid arthritis, inflammatory bowel disease, psoriatic arthritis and ankylosing spondylitis. Since their approval, concerns regarding safety have been raised. There is a risk of re-activation of granulomatous diseases, especially tuberculosis, and measures should be taken for detection and treatment of latent tuberculosis infections. Preliminary data suggest that anti-TNF therapy may be safe in chronic hepatitis C. However, TNF-alpha antagonists have resulted in re-activation of chronic hepatitis B if not given concurrently with antiviral therapy. Solid tumours do not appear to be increased with anti-TNF therapy. Variable rates of increased lymphoma risk have been described with anti-TNF therapy compared with the general population, although no increased risk was found compared with a rheumatoid arthritis population. Large phase II and III trials with TNF-alpha antagonists in advanced heart failure have shown trends towards a worse prognosis, and should therefore be avoided in this population. Both etanercept and infliximab are associated with the formation of autoantibodies, and these autoantibodies are rarely associated with any specific clinical syndrome. Rare cases of aplastic anaemia, pancytopenia, vasculitis and demyelination have been described with anti-TNF therapy. This chapter will discuss the safety profile and adverse events of the three commercially available TNF-alpha antagonists: etanercept, infliximab and adalimumab. The data presented in this review have been collected from published data, individual case reports or series, package inserts, the Food and Drug Administration postmarketing adverse events surveillance system, and abstracts from the American College of Rheumatology and European Congress of Rheumatology meetings for 2005.

Use of etanercept in human immunodeficiency virus (HIV) and acquired immunodeficiency syndrome (AIDS) patients

BACKGROUND

Etanercept (Enbrel, Amgen, Thousand Oaks, CA), a soluble p75 tumor necrosis factor receptor:FC (TNFR:FC) fusion protein for plasma cytokines, specifically tumor necrosis factor-alpha (TNF-alpha), is used in the treatment of immune-mediated rheumatic diseases. To our knowledge, the use of etanercept in patients with human immunodeficiency virus (HIV) and acquired immunodeficiency syndrome (AIDS) is relatively uncommon.

OBJECTIVE

The main purpose of this short review is to examine the safety of etanercept in patients with HIV/AIDS.

METHODS

A Medline search was conducted using the keywords etanercept and HIV and/or AIDS for any published articles between 1966 to the present (September 2004).

RESULTS

A case report, one case series, and one clinical trial pertained to the use of etanercept in HIV patients. No reports were found on the use of etanercept in AIDS. In addition, two case reports were found documenting the use of infliximab in HIV patients.

DISCUSSION

Preliminary reports indicate that the administration of etanercept does not appear to increase the morbidity or mortality rates in HIV. The inhibition of TNF-alpha may actually improve the symptoms of HIV/AIDS-associated aphthous ulcers, cachexia, dementia, fatigue, and fever, as well as help manage concomitant rheumatic diseases and psoriasis.

CONCLUSION

The use of etanercept shows promise for applications in disease management in patients with HIV/AIDS. Continued research efforts are necessary to establish the long-term safety and efficacy of etanercept and other biologic agents in this patient population.

Safety of antitumour necrosis factor (anti-TNF) therapy in patients with chronic viral infections: hepatitis C, hepatitis B, and HIV infection

Tumour necrosis factor alpha (TNFalpha) is a pivotal cytokine in host defences with broad ranging effects on the innate and adaptive immune systems. Clinically, TNFalpha inhibitors have demonstrated remarkable efficacy in a wide range of autoimmune and inflammatory disorders but clearly at the cost of heightened susceptibility to a variety of infections in those treated with these agents. Most reports to date have described increased susceptibility to intracellular pathogens in patients with underlying chronic viral infections, but little in the way of adverse event reporting in these patients has occurred. While the reported experience to date is rather limited, TNFalpha inhibitors have displayed a reasonable safety profile in the setting of some chronic viral infections and in certain circumstances have demonstrated adjunctive activity in the treatment of these infections. Given the high prevalence of chronic viral infections in patients who are candidates for anti-TNF therapy and the potential for these agents in the treatment of chronic viral illness, additional studies are urgently needed to assess the risks and benefits of such therapy in these populations.

Artificial T-cell receptors

Artificial T-cell receptors are generated by joining an Ag-recognizing domain (ectodomain) to the transmembrane and intracellular portion of a signaling molecule (endodomain). The ectodomain is most often derived from Ab variable chains, but may also be generated from T-cell receptor variable chains, as well as from other molecules. Various alternative ectodomain designs exist, with some comparative studies suggesting optimal forms. The endodomain most often used is the intracellular portion of CD-zeta. Although signaling by CD-zeta leads to IFN-n release and cell killing, it fails to transmit a full activation signal. Recently, unions of different signaling molecule segments have facilitated transmission of more potent signals, stimulating T-cell proliferation and overcoming this major limitation. Artificial T-cell receptors allow grafting of nearly any specificity to T cells. This allows generation of large numbers of specific T cells, without laborious selection and expansion procedures. Efficacy against tumors has been demonstrated in animal models. Phase I and II studies of T-cells transduced with artificial T-cell receptors as therapy for HIV infection have been performed. This rapidly advancing technology will make new strategies of adoptive immunotherapy possible.

Safety of Tumour Necrosis Factor-?? Antagonists

Tumour necrosis factor-alpha (TNFalpha) is a proinflammatory cytokine that is synthesised by a variety of cell types in response to infectious or inflammatory stimuli. Although TNFalpha plays an adaptive role in immune protection and wound healing at 'physiological' levels, excess TNFalpha production can lead to adverse consequences. TNFalpha is a pivotal cytokine involved in the pathogenesis and progression of rheumatoid arthritis (RA). TNFalpha antagonists have been shown to be effective in the treatment of signs and symptoms of RA and the US FDA has approved three TNFalpha antagonists, etanercept, infliximab, and most recently, adalimumab, for the treatment of RA. However, differences have emerged, with respect to their demonstrated efficacy in other diseases (e.g. Crohn's disease). Worldwide, over half a million patients have been treated with TNFalpha antagonists and concerns regarding their safety have been raised. There is a risk of reactivation of granulomatous diseases, especially tuberculosis, with all three agents and appropriate measures should be taken for detection and treatment of latent infections. An association between non-Hodgkin's lymphoma and treatment with TNFalpha antagonists has been reported, although patients with active, long-standing RA are already known to have an increased incidence of non-Hodgkin's lymphoma. No associations with solid tumours have been found to date. The biological plausibility of lymphomas associated with immunomodulatory agents raises concern and vigilance is appropriate until the relationship is fully characterised. Large phase II and III trials have shown a detrimental effect of TNFalpha antagonists in advanced heart failure and these agents should be avoided in this population. Rare case reports of drug-induced lupus, seizure disorder, pancytopenia and demyelinating diseases have been noted after TNFalpha antagonists and continued vigilance is warranted in patients on TNFalpha antagonists for the development of these diseases. At present there is no evidence implicating TNFalpha antagonists with embryotoxicity, teratogenicity or increased pregnancy loss.

Effect of tumour necrosis factor alpha antagonists on serum transaminases and viraemia in patients with rheumatoid arthritis and chronic hepatitis C infection

BACKGROUND

Tumour necrosis factor alpha (TNF alpha) antagonists are effective for the treatment of rheumatoid arthritis (RA), but concerns remain about the safety of these agents in the presence of chronic infections, including hepatitis C virus (HCV) infection.

OBJECTIVE

To examine the influence of treatment with TNF alpha antagonists on levels of HCV viraemia and serum transaminases in patients with RA and HCV.

METHODS

In a retrospective survey the course of 16 HCV infected patients with RA who had received the TNF alpha antagonists etanercept or infliximab was analysed. Eight additional patients with RA and HCV were also enrolled into a three month prospective trial of etanercept. Serum concentrations of albumin, alkaline phosphatase, aspartate aminotransferase, alanine aminotransferase, and HCV were followed.

RESULTS

Viraemia was measured in 22 patients receiving a TNF alpha antagonist at the start of treatment and after 1-34 months (median 9 months follow up). Twenty four patients had serial tests of liver related enzymes and albumin. None of the differences between liver related tests at baseline and at follow up achieved significance (p>0.05). Similarly, the mean HCV measurement at 1-3, 4-6, 7-12, and 13-34 months did not differ significantly from baseline (p>0.05).

CONCLUSION

In this study, liver related blood tests and HCV viral load measurements did not change substantially. These findings suggest that TNF alpha antagonists merit further study for the treatment of RA in HCV infected patients. Larger and longer term studies are still needed.

The induction of Toll-like receptor tolerance enhances rather than suppresses HIV-1 gene expression in transgenic mice

Microbial-induced proinflammatory pathways are thought to play a key role in the activation of human immunodeficiency virus type 1 (HIV-1) gene expression. The induction of Toll-like receptor (TLR) tolerance leads to a complex reprogramming in the pattern of inflammatory gene expression and down-modulates tumor necrosis factor alpha (TNF-alpha), interleukin (IL)-1, and IL-6 production. Using transgenic (Tg) mice that incorporate the entire HIV-1 genome, including the long-terminal repeat, we have previously demonstrated that a number of different TLR ligands induce HIV-1 gene expression in cultured splenocytes as well as purified antigen-presenting cell populations. Here, we have used this model to determine the effect of TLR-mediated tolerance as an approach to inhibiting microbial-induced viral gene expression in vivo. Unexpectedly, Tg splenocytes and macrophages, rendered tolerant in vitro to TLR2, TLR4, and TLR9 ligands as assessed by proinflammatory cytokine secretion and nuclear factor-kappaB activation, showed enhanced HIV-1 p24 production. A similar enhancement was observed in splenocytes tolerized and then challenged with heterologous TLR ligands. Moreover, TLR2- and TLR4-homotolerized mice demonstrated significantly increased plasma p24 production in vivo despite lower levels of TNF-alpha. Together, these results demonstrate that HIV-1 expression is enhanced in TLR-reprogrammed host cells, possibly reflecting a mechanism used by the virus to escape the effects of microbial-induced tolerance during natural infection in vivo.

Mechanisms of CD4+ T lymphocyte cell death in human immunodeficiency virus infection and AIDS

AIDS, caused by the retroviruses human immunodeficiency virus type 1 and type 2 (HIV-1 and HIV-2), has reached pandemic proportions. Therefore, it is critical to understand how HIV causes AIDS so that appropriate therapies can be formulated. Primarily, HIV infects and kills CD4(+) T lymphocytes, which function as regulators and amplifiers of the immune response. In the absence of effective anti-retroviral therapy, the hallmark decrease in CD4(+) T lymphocytes during AIDS results in a weakened immune system, impairing the body's ability to fight infections or certain cancers such that death eventually ensues. The major mechanism for CD4(+) T cell depletion is programmed cell death (apoptosis), which can be induced by HIV through multiple pathways. Death of HIV-infected cells can result from the propensity of infected lymphocytes to form short-lived syncytia or from an increased susceptibility of the cells to death. However, the apoptotic cells appear to be primarily uninfected bystander cells and are eradicated by two different mechanisms: either a Fas-mediated mechanism during activation-induced cell death (AICD), or as a result of HIV proteins (Tat, gp120, Nef, Vpu) released from infected cells stimulating apoptosis in uninfected bystander cells. There is also evidence that as AIDS progresses cytokine dysregulation occurs, and the overproduction of type-2 cytokines (IL-4, IL-10) increases susceptibility to AICD whereas type-1 cytokines (IL-12, IFN-gamma) may be protective. Clearly there are multiple causes of CD4(+) T lymphocyte apoptosis in AIDS and therapies that block or decrease that death could have significant clinical benefit.

Effect of etanercept (Enbrel) on interleukin 6, tumor necrosis factor alpha, and markers of immune activation in HIV-infected subjects receiving interleukin 2

The effect of etanercept, a soluble p75 tumor necrosis factor (TNF) receptor:Fc fusion protein (Enbrel; Immunex, Seattle, WA) on plasma cytokines was evaluated in 11 HIV-infected subjects receiving highly active antiretroviral therapy (HAART) for 28 weeks with or without subcutaneous or intravenous recombinant human interleukin 2 (rhIL-2). Plasma IL-6 and C-reactive protein (CRP) levels increased after rhIL-2 treatment. Etanercept pretreatment attenuated these increases. Median plasma IL-6 levels were 20.29 pg/ml 4 days after rhIL-2 and 7.87 pg/ml 4 days after etanercept and rhIL-2 (p = 0.22); median CRP levels were 78.73 and 46.16 microg/ml, respectively (p = 0.03). An effect on TNF bioactivity could not be assessed as all measurements were below limits of detection. No significant changes were seen in temperature or plasma levels of IL-4, IL-10, IL-12, interferon gamma, or HIV-1 RNA levels. All subjects had undetectable or low-level HIV-1 RNA levels before etanercept dosing. One subject died; however, her death was thought to be unrelated to etanercept. Pretreatment with etanercept may blunt activation of IL-6 and CRP expression induced by rhIL-2. The safety and utility of etanercept in HIV-infected persons should be explored further.

Mechanisms of HIV-associated lymphocyte apoptosis

Infection with the human immunodeficiency virus (HIV) is associated with a progressive decrease in CD4 T-cell number and a consequent impairment in host immune defenses. Analysis of T cells from patients infected with HIV, or of T cells infected in vitro with HIV, demonstrates a significant fraction of both infected and uninfected cells dying by apoptosis. The many mechanisms that contribute to HIV-associated lymphocyte apoptosis include chronic immunologic activation; gp120/160 ligation of the CD4 receptor; enhanced production of cytotoxic ligands or viral proteins by monocytes, macrophages, B cells, and CD8 T cells from HIV-infected patients that kill uninfected CD4 T cells; and direct infection of target cells by HIV, resulting in apoptosis. Although HIV infection results in T-cell apoptosis, under some circumstances HIV infection of resting T cells or macrophages does not result in apoptosis; this may be a critical step in the development of viral reservoirs. Recent therapies for HIV effectively reduce lymphoid and peripheral T-cell apoptosis, reduce viral replication, and enhance cellular immune competence; however, they do not alter viral reservoirs. Further understanding the regulation of apoptosis in HIV disease is required to develop novel immune-based therapies aimed at modifying HIV-induced apoptosis to the benefit of patients infected with HIV.

Mechanisms of HIV-associated lymphocyte apoptosis

Infection with the human immunodeficiency virus (HIV) is associated with a progressive decrease in CD4 T-cell number and a consequent impairment in host immune defenses. Analysis of T cells from patients infected with HIV, or of T cells infected in vitro with HIV, demonstrates a significant fraction of both infected and uninfected cells dying by apoptosis. The many mechanisms that contribute to HIV-associated lymphocyte apoptosis include chronic immunologic activation; gp120/160 ligation of the CD4 receptor; enhanced production of cytotoxic ligands or viral proteins by monocytes, macrophages, B cells, and CD8 T cells from HIV-infected patients that kill uninfected CD4 T cells; and direct infection of target cells by HIV, resulting in apoptosis. Although HIV infection results in T-cell apoptosis, under some circumstances HIV infection of resting T cells or macrophages does not result in apoptosis; this may be a critical step in the development of viral reservoirs. Recent therapies for HIV effectively reduce lymphoid and peripheral T-cell apoptosis, reduce viral replication, and enhance cellular immune competence; however, they do not alter viral reservoirs. Further understanding the regulation of apoptosis in HIV disease is required to develop novel immune-based therapies aimed at modifying HIV-induced apoptosis to the benefit of patients infected with HIV.

Lipopolysaccharide-induced HIV-1 expression in transgenic mice is mediated by tumor necrosis factor-alpha and interleukin-1, but not by interferon-gamma nor interleukin-6

BACKGROUND

As serum HIV-1 load correlates well with the prognosis of the disease, it is suggested that the viral load is one of the major determinants of the disease progression of AIDS. Accordingly, HIV-1 activation mechanisms were extensively studied in vitro, and involvement of cytokines including tumor necrosis factor (TNF)-alpha, interleukin (IL)-1, IL-6 and interferon (IFN)-gamma has been suggested in this process. However, so far the roles of these cytokines in the HIV-1 expression in vivo have not been well elucidated because of the lack of appropriate animal disease models.

OBJECTIVE

To elucidate the roles of cytokines in HIV-1 activation in vivo.

DESIGN AND METHODS

Transgenic mice carrying a defective HIV-1 genome were used as a model for HIV-1 carriers. In order to examine the possible involvement of cytokines in HIV-1 expression, TNF-alpha-, IL-1-, IL-6- and IFN-gamma-deficient HIV-1 transgenic mice, were produced and HIV-1 expression was analyzed after activation with bacterial lipopolysaccharides (LPS).

RESULTS

HIV-1 expression in the transgenic mouse spleen was activated 10- to 20-fold by LPS, and the serum p24 Gag protein levels reached 400 pg/ml, which is nearly equal to the levels that occur in AIDS patients. However, this augmentation was suppressed by 60% in TNF-alpha-deficient mice and by 40% in IL-1alpha/beta-deficient mice. In contrast, no suppression was observed in either IL-6-, IFN-gamma-, IL-1alpha, or IL-1beta-deficient mice.

CONCLUSIONS

Results suggest that TNF-alpha and IL-1 play important roles in HIV-1 gene activation and selective suppression of these cytokines could improve clinical prognosis and potentially slow progression of the disease.

HMG-1 as a late mediator of endotoxin lethality in mice

Endotoxin, a constituent of Gram-negative bacteria, stimulates macrophages to release large quantities of tumor necrosis factor (TNF) and interleukin-1 (IL-1), which can precipitate tissue injury and lethal shock (endotoxemia). Antagonists of TNF and IL-1 have shown limited efficacy in clinical trials, possibly because these cytokines are early mediators in pathogenesis. Here a potential late mediator of lethality is identified and characterized in a mouse model. High mobility group-1 (HMG-1) protein was found to be released by cultured macrophages more than 8 hours after stimulation with endotoxin, TNF, or IL-1. Mice showed increased serum levels of HMG-1 from 8 to 32 hours after endotoxin exposure. Delayed administration of antibodies to HMG-1 attenuated endotoxin lethality in mice, and administration of HMG-1 itself was lethal. Septic patients who succumbed to infection had increased serum HMG-1 levels, suggesting that this protein warrants investigation as a therapeutic target.

Effect of a chimeric antibody to tumor necrosis factor-alpha on cytokine and physiologic responses in patients with severe sepsis--a randomized, clinical trial

OBJECTIVES

Tumor necrosis factor (TNF)-alpha appears central to the pathogenesis of severe sepsis, but aspects of the cytokine cascade and the link to physiologic responses are poorly defined. We hypothesized that a monoclonal antibody to TNF-alpha given early in the course of severe sepsis would modify the pattern of systemic cytokine release and, as a consequence, resuscitation fluid requirements, net proteolysis, and hypermetabolism would be reduced.

DESIGN

Randomized, double-blind, placebo-controlled trial.

SETTING

Critical Care Unit and University Department of Surgery in a single tertiary care center.

PATIENTS

Fifty-six patients (from 92 eligible patients) with severe sepsis. Twenty-eight patients were randomized to treatment, and were comparable with the placebo group for age, gender, race, Acute Physiology and Chronic Health Evaluation II score, and site and type of infection.

INTERVENTIONS

A 300-mg single dose of cA2 (a chimeric neutralizing antibody to TNF-alpha) was given intravenously within 12 hrs of the onset of severe sepsis. Standard surgical and intensive care therapy was otherwise delivered.

MEASUREMENTS AND MAIN RESULTS

Plasma concentrations of TNF-alpha, interleukin (IL)-1beta IL-6, IL-8, IL-10, soluble 75-kilodalton TNF-alpha receptor (sTNFR-75), and IL-1beta receptor antagonist (IL-1ra) were measured by sandwich enzyme-linked immunosorbent assay before cA2 infusion, 8 hrs later, and then daily for a minimum of 4 days. Sequential changes in total body protein, body water spaces, and resting energy expenditure over 21 days were measured, as soon as patients achieved hemodynamic stability, by in vivo neutron activation analysis, tritium and bromide dilution, and indirect calorimetry, respectively. Twenty-one patients died, ten having received cA2. Suppression of measurable TNF-alpha was observed at 8 hrs with subsequent rebound by 24 hrs after cA2 treatment. The concentrations of other cytokines were high, were not reduced by intervention, and decreased logarithmically over 5 days. Both groups reached hemodynamic stability at similar times (57.5 +/- 11.8 hrs in controls vs. 58.6 +/- 9.2 hrs in the cA2 group) and following similar volumes of infused fluids (29.1 +/- 3.4 L vs. 28.9 +/- 4.4 L). No differences in net proteolysis, resolution of body water expansion, or alteration in resting energy expenditure were demonstrated.

CONCLUSION

A single dose of cA2 did not alter the overall pattern of cytokine activation or the profound derangements in physiologic function that accompany severe sepsis.

Cytokines and chemokines in HIV infection: implications for therapy

HIV infection is associated with both a hyperactivity of the immune system and decreased immune responses against specific antigens. A similar pattern is observed when considering cytokine production in HIV-infected patients. Several cytokines are spontaneously produced at an increased level, whereas other cytokines playing an important role during cell-mediated immune responses are produced at a low level following stimulation. This deregulation of cytokine production may participate to the immune deficiency, both by impairing immune responses and by accelerating CD4+ T lymphocyte destruction. Chemokine receptors have recently been shown to function as coreceptors for the virus, and to govern its cellular tropism. Heterogeneous expression of chemokine receptor may contribute to differences in infectability as well as in rate of progression of the disease between individuals. Better understanding of the role of cytokines and chemokines in HIV infection suggests new therapeutic approaches where administration of cytokines or cytokine antagonists may allow the immune system to function in better conditions, to stimulate antiviral and antiinfectious immune defenses, and to limit viral spread.

Correlation between plasma levels of cytokines and HIV-1 RNA copy number in HIV-infected patients

The plasma levels of HIV-1 RNA, tumor necrosis factor alpha (TNF-alpha), soluble receptors type II of TNF-alpha (sTNF-alpha RII), soluble receptors of interleukin-4 (sR IL-4), interleukin-6 (IL-6), soluble receptors of interleukin-6 (sR IL-6), granulocyte macrophage colony stimulating factor (GM-CSF), soluble receptors of GM-CSF (sR GM-CSF), RANTES, MIP-1 alpha and MIP-1 beta were measured in 80 HIV-infected patients. All patients had not been treated previously with antiretroviral drugs and did not present a recent history of opportunistic infection. A statistically significant correlation was found between HIV-1 RNA and TNF-alpha (p = 0.005) or sTNF-alpha RII levels (p < 0.001). RANTES and MIP-1 alpha levels did not correlate with HIV-1 RNA. MIP-1 beta levels were correlated with plasma RNA titers in patients with CD4+ T cells < 200 x 10(6)/l (p = 0.03). MIP-1 alpha and sR IL-4 levels were significantly different according to the CD4+ T cell range (p = 0.003 and p = 0.0002, respectively). GM-CSF and sR GM-CSF were undetectable in each case. These data confirm that HIV-1 replication in the plasma is correlated with TNF-alpha levels, but do not show a clear correlation with levels of the chemokines studied.

A double-blind placebo-controlled phase II trial of thalidomide in asymptomatic HIV-positive patients: clinical tolerance and effect on activation markers and cytokines

A randomized double-blind, placebo-controlled study was performed to determine the safety, efficacy, and effect of thalidomide on a variety of immunological and biochemical parameters in asymptomatic human immunodeficiency virus (HIV)-positive patients. Nineteen male patients with elevated markers of immune activation and CD4 cell counts above 400/mm3 were randomized to either placebo or thalidomide at 100 mg/day for 24 weeks. However, only 3 (of 10) patients receiving thalidomide completed all 24 weeks compared to 6 (of 9) patients receiving placebo. This was mainly due to fatigue (somnolence is a recognized side effect), although this was also seen to a lesser extent in the placebo group and so may not be drug attributable. No significant changes in CD4/CD8 count, activation markers, TNF-alpha, or TNFR1 were observed. However, a nonsignificant trend toward inhibition of mitogen-induced TNF-alpha production was observed in the thalidomide arm. The lack of systemic effect and the lower tolerance of thalidomide (at this dose) in asymptomatic patients highlights the need for pharmacokinetic analysis to address possible absorption problems and the need for more potent and less toxic TNF-alpha inhibitors to be developed for use in this type of study.

Single-dose pharmacokinetics of thalidomide in human immunodeficiency virus-infected patients

The pharmacokinetics of thalidomide in nine human immunodeficiency virus-infected patients were studied. Single doses of thalidomide were well absorbed, with mean peak concentrations (+/- standard deviations) of 1.17 +/- 0.21 and 3.47 +/- 1.14 microg/ml in the 100- and 300-mg dosing groups, respectively, and the mean elimination half-life was approximately 6 h. Adverse effects were mild, with drowsiness being reported for seven of nine patients.

Structure-based design and characterization of exocyclic peptidomimetics that inhibit TNF alpha binding to its receptor

Exocyclic small peptidomimetics corresponding to three critical binding sites of tumor necrosis factor (TNF)-receptor(I) have been designed based on atomic features deduced from the crystal structures of TNF alpha and the TNF beta/TNF-receptor(I) complex and a model of an anti-TNF alpha monoclonal antibody. TNF alpha antagonistic activities were evaluated by binding assays using soluble receptor or intact receptor on cells as well as an apoptosis/cytotoxicity assay. The most critical interaction site for rational design of peptidomimetics was localized to the loop1/domain3 of the TNF-receptor. The best antagonist showed 5 microM inhibition in the binding assay. Biologically, the mimetics inhibited TNF alpha-mediated apoptosis.