Abatacept treatment does not exacerbate chronicMycobacterium tuberculosis infection in mice

Immunosuppressants alter the immune response associated with Glucantime® treatment for Leishmania infantum infection in a mouse model

Background

Immunosuppression is a major risk factor for the development of visceral leishmaniasis (VL). The number of patients receiving immunosuppressant drugs such as TNF antagonist (anti-TNF) and methotrexate (MTX) is increasing. In these patients, VL is more severe, their response to treatment poorer, and they are at higher risk of relapse, a consequence (largely) of the poor and inappropriate immune response they develop.

Objectives

To examine the effect of immunosuppressive treatment on the host immune response and thus gain insight into the reduced efficacy of pentavalent antimonials in these patients. Experiments were performed using BALB/c mice immunosuppressed with anti-TNF or MTX, infected with Leishmania infantum promastigotes, and then treated with Glucantime® at clinical doses.

Results

Immunosuppression with both agents impeded parasite elimination from the spleen and bone marrow. Low pro-inflammatory cytokine production by CD4+ and CD8+ T cells was detected, along with an increase in PD-1 and IL-10 expression by B and T cells in the immunosuppressed groups after treatment.

Conclusion

The immunosuppressed mice were unable to develop specific cellular immunity to the parasite, perhaps explaining the greater risk of VL relapse seen in pharmacologically immunosuppressed human patients.

Secondary immunodeficiencies and infectious considerations of biologic immunomodulatory therapies

Biologic immunomodulatory medications have rapidly expanded in the previous decades, providing new treatment options for individuals with a spectrum of oncologic, allergic, rheumatologic, and neurologic conditions. Biologic therapies alter immune function and can impair key host defense mechanisms, resulting in secondary immunodeficiency and increased infectious risks. Biologic medications can increase general risk for upper respiratory tract infections but can also be associated with unique infectious risks owing to distinct mechanisms of action. With the widespread use of these medications, providers in every area of medicine will likely care for individuals receiving biologic therapies and understanding their potential infectious complications can help mitigate these risks. This practical review discusses the infectious implications of biologics by class of medication and provides recommendations regarding the examination and screening both before therapy initiation and while the patient is receiving the medication. With this knowledge and background, providers can reduce risk whereas patients receive the treatment benefits of these biologic medications.

Abatacept (Cytotoxic T Lymphocyte Antigen 4-Fragment Crystallizable) Reduces Allergic Inflammation of Ovalbumin-Sensitized Mice

BACKGROUND

Abatacept (Aba) is a cytotoxic T-lymphocyte antigen-4 and fragment crystallizable fusion protein. Aba blocks B7/Cluster of differentiation 28 - cytotoxic T-lymphocyte antigen-4 costimulatory pathway, inhibits cluster of differentiation 4+ T-cell activation, and is used as an anti-inflammatory drug.

OBJECTIVES

We conducted this study to assess the effectiveness of Aba in the treatment of allergic rhinitis (AR) in a mouse model.

METHODS

We divided 40 four-week-old BALB/c mice into four groups: control group (n = 10), positive control group (AR, n = 10), Aba group (AR + Aba, n = 10), and dexamethasone group (AR + Dex, n = 10). Mice in each group were challenged intranasally with daily ovalbumin (OVA) administration. Episodes of sneezing and nose rubbing were counted. Mice were sacrificed on day 42 and cytokines were measured in nasal lavage fluid. Nasal mucosae of five mice from each group were used for reverse transcriptase-polymerase chain reaction and western blot assay. Samples were collected from five mice from each group for histological analysis.

RESULTS

Symptoms of AR significantly improved in the AR + Aba and AR + Dex groups compared with the AR group. Fewer eosinophils and goblet cells were seen in the AR + Aba and AR + Dex groups compared with the AR group. Both the AR + Aba and AR + Dex groups showed a significant decrease in nasal T helper 2 cytokine levels, including interleukin (IL)-4, IL-5, IL-13 and T cell activation related IL-17A, and interferon gamma (IFN- γ). Total immunoglobulin (Ig) E and OVA-specific IgG1 levels were also significantly lower in the AR + Aba and AR + Dex groups. OVA-specific IgE level was also significantly lower in the AR + Aba than AR group.

CONCLUSIONS

Aba suppresses allergic inflammation and appears to be a good treatment for AR.

Long-term good outcome of the fibrocavitary form of pulmonary Mycobacterium avium complex disease with concomitant abatacept monotherapy in a patient with rheumatoid arthritis

A 53-year-old woman diagnosed with rheumatoid arthritis (RA) demonstrated thick-walled large cavities with consolidation in the left upper lobe on chest computed tomography (CT). Mycobacterium avium was isolated from sputum cultures, and she was diagnosed as having the fibrocavitary (FC) form of pulmonary Mycobacterium avium complex (MAC) disease. Clarithromycin-containing, multidrug, anti-MAC chemotherapy was started immediately. After 7 months, the cavitary lesions improved, and sputum cultures showed negative conversion. Thereafter, abatacept monotherapy was started due to high RA disease activity. Clinical remission of RA has been sustained and cavitary lesions disappeared by concomitant abatacept and anti-MAC therapy for more than 5 years. Immediate initiation of anti-MAC therapy and prior confirmed efficacy are needed for the treatment of the FC form. Abatacept and anti-MAC therapy could be continued, leading to the withdrawal of prednisolone, along with careful observation by strict chest CT evaluation and repeated sputum cultures. Biologics are generally contraindicated for pulmonary MAC disease, particularly the FC form. When there is a pre-existing lung lesion apparently of FC type, abatacept cannot be started without prior anti-MAC chemotherapy. This case suggests that abatacept may be carefully used to avoid progressive joint destruction after FC lesions of pulmonary MAC disease are resolved.

Abatacept for rheumatoid arthritis complicated by disseminated cryptococcosis: a case report

A 78-year-old man developed disseminated cryptococcosis with central nervous system involvement as encapsulated yeast cells were detected in transbronchial biopsy and skin biopsy specimens, and cerebrospinal fluid. Cryptococcus neoformans was confirmed by culture. He had been treated with low-dose prednisolone and methotrexate for rheumatoid arthritis. He started receiving antifungal therapy with intravenous liposomal amphotericin B followed by oral fluconazole. Methotrexate was discontinued. Approximately 4 months after the course of intravenous liposomal amphotericin B was completed, he complained of pain and swelling of the right wrist, which suggested that rheumatoid arthritis was worsening. Abatacept therapy was initiated along with antifungal therapy, and his symptoms relieved. After 24 months of antifungal therapy, although he was still receiving oral fluconazole, he was doing well and the serum cryptococcal antigen had become negative. Disseminated cryptococcosis is an important opportunistic infection associated with low-dose methotrexate for rheumatoid arthritis. Abatacept therapy may be feasible in strictly selected patients with rheumatoid arthritis complicated with cryptococcosis concomitantly with intensive anti-fungal therapy.

Effect of immunosuppressants on the parasite load developed in, and immune response to, visceral leishmaniasis: A comparative study in a mouse model

The increasing use of immunosuppressants in areas where visceral leishmaniasis (VL) is endemic has increased the number of people susceptible to developing more severe forms of the disease. Few studies have examined the quality of the immune response in immunosuppressed patients or experimental animals with VL. The present work characterises the parasite load developed in, and immune response to, Leishmania infantum-induced VL in C57BL/6 mice that, prior to and during infection, received immunosuppressant treatment with methylprednisolone (MPDN), anti-tumour necrosis factor (anti-TNF) antibodies, or methotrexate (MTX). The latter two treatments induced a significant reduction in the number of CD4+ T lymphocytes over the infection period. The anti-TNF treatment was also associated with a higher parasite load in the liver and a lower parasite load in the spleen. This, plus a possibly treatment-induced reduction in the number of cytokine-producing Th1 cells in the spleen, indicates the development of more severe VL. Interestingly, the MPDN and (especially) MTX treatments provoked a greater presence of soluble Leishmania antigen-specific multi-cytokine-producing T cells in the spleen and a lower liver parasite load than in control animals. These results highlight the need to better understand how immunosuppressant treatments might influence the severity of VL in human patients.

Tuberculosis and targeted synthetic or biologic DMARDs, beyond tumor necrosis factor inhibitors

Patients with autoimmune rheumatic diseases (ARD) have an increased risk for tuberculosis (TB). The use of tumor necrosis factor inhibitors (TNFi) and glucocorticoids in these patients has been associated with an increased prevalence of latent TB reactivation. Over the last few years, several biologic disease-modifying anti-rheumatic drugs (bDMARDs), other than TNFi (e.g. rituximab, abatacept, tocilizumab, secukinumab) and targeted synthetic DMARDs (tsDMARDs) [e.g. apremilast, Janus kinase (JAK) inhibitors] have been used for the treatment of patients with ARD. For many of these drugs, especially the newer ones like JAK inhibitors or antibodies against interleukin (IL)-23, most data stem from randomized clinical trials and few are available from real life clinical experience. We sought to review the current evidence for TB risk in patients with ARD treated with tsDMARDs or bDMARDs, other than TNFi. It seems that some of these drugs are associated with a lower TB risk, indirectly compared with TNFi treatment. In fact, it appears that rituximab, apremilast and inhibitors of IL-17 and IL-23 might be safer, while more data are needed for JAK inhibitors. As seen in TNFi, risk for TB is more pronounced in TB-endemic areas. Screening for latent TB must precede initiation of any tsDMARDs or bDMARDs. The growing use of non-TNFi agents has raised the need for more real-life studies that would compare the risk for TB between TNFi and other treatment modalities for ARD. Knowledge about the TB-safety profile of these drugs could help in the decision of drug choice in patients with confirmed latent TB infection or in TB endemic areas.

Infectious Complications of Biological and Small Molecule Targeted Immunomodulatory Therapies

The past 2 decades have seen a revolution in our approach to therapeutic immunosuppression. We have moved from relying on broadly active traditional medications, such as prednisolone or methotrexate, toward more specific agents that often target a single receptor, cytokine, or cell type, using monoclonal antibodies, fusion proteins, or targeted small molecules. This change has transformed the treatment of many conditions, including rheumatoid arthritis, cancers, asthma, and inflammatory bowel disease, but along with the benefits have come risks. Contrary to the hope that these more specific agents would have minimal and predictable infectious sequelae, infectious complications have emerged as a major stumbling block for many of these agents. Furthermore, the growing number and complexity of available biologic agents makes it difficult for clinicians to maintain current knowledge, and most review articles focus on a particular target disease or class of agent. In this article, we review the current state of knowledge about infectious complications of biologic and small molecule immunomodulatory agents, aiming to create a single resource relevant to a broad range of clinicians and researchers. For each of 19 classes of agent, we discuss the mechanism of action, the risk and types of infectious complications, and recommendations for prevention of infection.

Abatacept treatment impairs the cell migration and wound healing of oral ulcers in rats: Role of interleukin (IL)-1β, -6 and -10 and CD8/CD30 cells: Influence of abatacept treatment on oral wound healing: Experimental model on rats

The present study aimed to evaluate the healing process of ulcers in the jugal mucosa of Wistar rats treated with abatacept. The rats were randomly assigned to four groups: saline-treated control (0.3 mL/kg) abatacept-treated groups at dosages of 3.2, 8.0 and 20.0 mg/kg/week. After two weeks of subcutaneous (SC) administration, ulcers were introduced into the left jugal mucosa with an 8-mm diameter punch. SC administration was continued until euthanasia (after 1, 3, 7, 14 and 21 days of ulceration), and ulcers were clinically measured and animals weighed. Histological slides were evaluated (healing scores and polymorphonuclear, mononuclear, vessel, and fibroblast/myofibroblast counts). We also performed collagenesis analysis (Picrosirius Red) and immunohistochemistry (induced nitric oxide synthase (iNOS), interleukin (IL)-1beta (1β), -6, -10, plus the analysis of CD8 and CD30). The experiment was repeated to perform a vascular permeability assay. ANOVA 1-way or 2-way/Bonferroni and Kruskal-Wallis/Dunn tests were used for statistical analysis (GraphPad Prism 5.0®, p < 0.05). Abatacept treatment reduced the ulcer diameter and the numbers of polymorphonuclear and mononuclear cells; reduced the CD8+/CD30+ ratio and vascular permeability; and increased collagenesis and IL-10 expression at the beginning of the protocol. At the highest dose, there was a delay in repair and vascular proliferation; a reduction in the number of fibroblasts/myofibroblasts; and prolongation of iNOS, IL- and IL- expression. We conclude that abatacept accelerates the healing of oral ulcers by reducing the migration of inflammatory cells, but overdose of abatacept leads to delayed repair and prolongation of proinflammatory cytokine expression.

Comparison of adverse events of biologicals for treatment of juvenile idiopathic arthritis: a systematic review

Objectives: Treatment of juvenile idiopathic arthritis has changed rapidly since the introduction of various biologics almost twenty years ago. Many clinical trials have been performed to monitor efficacy and safety of new agents. The aim of this review is to summarize safety concerns, which were observed during prospective clinical trials. Methods: Since etanercept was the first biologic approved and remains the most frequently used, as first biologic in polyarticular JIA patients, the authors calculated the relative risk of the adverse events for all examined biologicals and compared the values with the value of etanercept. Results: Relative rates for all adverse events showed similar rates for etanercept, infliximab, golimumab, and tocilizumab, whereas adalimumab showed higher rates and abatacept lower rates. Comparison of rates for serious adverse events demonstrated, that rates seemed comparable for etanercept, adalimumab, infliximab, and tocilizumab. Again, abatacept showed a lower rate, whereas golimumab seems to have a higher relative risk for serious adverse events. Rate of infection was lowest in patients treated with abatacept or tocilizumab, patients treated with etanercept, adalimumab and Infliximab again had similar rates. Conclusion: The safety profiles of actually approved biologics are highly acceptable. However, further observation, especially long-term observation through registry studies, is required.

The YIN and YANG of lipoproteins in developing and preventing infectious arthritis by Staphylococcus aureus

Rapid bone destruction often leads to permanent joint dysfunction in patients with septic arthritis, which is mainly caused by Staphylococcus aureus (S. aureus). Staphylococcal cell wall components are known to induce joint inflammation and bone destruction. Here, we show that a single intra-articular injection of S. aureus lipoproteins (Lpps) into mouse knee joints induced chronic destructive macroscopic arthritis through TLR2. Arthritis was characterized by rapid infiltration of neutrophils and monocytes. The arthritogenic effect was mediated mainly by macrophages/monocytes and partially via TNF-α but not by neutrophils. Surprisingly, a S. aureus mutant lacking Lpp diacylglyceryl transferase (lgt) caused more severe joint inflammation, which coincided with higher bacterial loads of the lgt mutant in local joints than those of its parental strain. Coinjection of pathogenic S. aureus LS-1 with staphylococcal Lpps into mouse knee joints caused improved bacterial elimination and diminished bone erosion. The protective effect of the Lpps was mediated by their lipid moiety and was fully dependent on TLR2 and neutrophils. The blocking of CXCR2 on neutrophils resulted in total abrogation of the protective effect of the Lpps. Our data demonstrate that S. aureus Lpps elicit innate immune responses, resulting in a double-edged effect. On the one hand, staphylococcal Lpps boost septic arthritis. On the other hand, Lpps act as adjuvants and activate innate immunity, which could be useful for combating infections with multiple drug-resistant strains.

Rapid bone destruction often leads to permanent joint dysfunction in septic arthritis, which is mainly caused by S. aureus. Despite advances in the use of antibiotics, permanent reductions in joint function occur in up to 50% of patients, who may also need joint replacement surgery. Additional challenge is posed by increasing antibiotic resistance of S. aureus, causing significant clinical and economic consequences. Although the outcome is poor, the current treatments for septic arthritis remain unchanged since many decades. It is largely unknown which bacterial factors cause aggressive joint damage. Here, we show that a single intra-articular injection of S. aureus lipoproteins (Lpps) into mouse knee joints induced chronic destructive macroscopic arthritis, and the monocytes/macrophages were the main culprit. However, coinjection of pathogenic S. aureus with Lpps into mouse knee joints attenuated the disease. The protective effect of Lpps was mediated by their lipid moiety, TLR2 on the host cells, neutrophil chemokine release, and consequent neutrophil recruitment. Our finding might be used as a novel concept in the treatment of multidrug-resistant bacterial infections.

Interrupting oral infection of Porphyromonas gingivalis with anti-FimA antibody attenuates bacterial dissemination to the arthritic joint and improves experimental arthritis

Rheumatoid arthritis (RA) is a chronic autoimmune disease that typically results in strong inflammation and bone destruction in the joints. It is generally known that the pathogenesis of RA is linked to cardiovascular and periodontal diseases. Though rheumatoid arthritis and periodontitis share many pathologic features such as a perpetual inflammation and bone destruction, the precise mechanism underlying a link between these two diseases has not been fully elucidated. Collagen-induced arthritis (CIA) mice were orally infected with Porphyromonas gingivalis (Pg) or Pg preincubated with an anti-FimA antibody (FimA Ab) specific for fimbriae that are flexible appendages on the cell surface. Pg-infected CIA mice showed oral microbiota disruption and increased alveolar bone loss and had synovitis and joint bone destruction. However, preincubation with FimA Ab led to a significant reduction in the severity of both oral disease and arthritis. Moreover, FimA Ab attenuated bacterial attachment and aggregation on human gingival and rheumatoid arthritis synovial fibroblasts. In addition, we discovered bacteria may utilize dendritic cells, macrophages and neutrophils to migrate into the joints of CIA mice. These results suggest that disrupting Pg fimbriae function by FimA Ab ameliorates RA.

Treatment with Biologicals in Rheumatoid Arthritis: An Overview

Management and therapy of rheumatoid arthritis (RA) has been revolutionized by the development and approval of the first biological disease-modifying antirheumatic drugs (bDMARDs) targeting tumor necrosis factor (TNF) α at the end of the last century. Today, numerous efficacious agents with different modes of action are available and achievement of clinical remission or, at least, low disease activity is the target of therapy. Early therapeutic interventions aiming at a defined goal of therapy (treat to target) are supposed to halt inflammation, improving symptoms and signs, and preserving structural integrity of the joints in RA. Up to now, bDMARDs approved for therapy in RA include agents with five different modes of action: TNF inhibition, T cell co-stimulation blockade, IL-6 receptor inhibition, B cell depletion, and interleukin 1 inhibition. Furthermore, targeted synthetic DMARDs (tsDMARDs) inhibiting Janus kinase (JAK) and biosimilars also are approved for RA. The present review focuses on bDMARDs and tsDMARDS regarding similarities and possible drug-specific advantages in the treatment of RA. Furthermore, compounds not yet approved in RA and biosimilars are discussed. Following the American College of Rheumatology (ACR) and European League Against Rheumatism (EULAR) recommendations, specific treatment of the disease will be discussed with respect to safety and efficacy. In particular, we discuss the question of favoring specific bDMARDs or tsDMARDs in the two settings of insufficient response to methotrexate and to the first bDMARD, respectively.

Both anti-TNF and CTLA4 Ig treatments attenuate the disease severity of staphylococcal dermatitis in mice

Background

RA patients being treated with biologics are known to have an increased risk of infections. We recently demonstrated that both CTLA4 Ig and anti-TNF treatment aggravate systemic Staphylococcus aureus (S. aureus) infection in mice, but with distinct clinical manifestations. However, the effects of CTLA4 Ig and anti-TNF treatments on a local S. aureus infection (e.g., skin infection) might differ from their effects on a systemic infection.

Aims

The aim of this study was to examine the differential effects of anti-TNF versus CTLA4 Ig treatment on S. aureus skin infections in mice.

Method

Abatacept (CTLA4 Ig), etanercept (anti-TNF treatment) or PBS was given to NMRI mice subcutaneously inoculated with S. aureus strain SH1000. The clinical signs of dermatitis, along with histopathological changes due to skin infection, were compared between the groups.

Results

Both CTLA4 Ig and anti-TNF treatment resulted in less severe skin infections and smaller post-infectious hyperpigmentation compared with controls. Consistent with the clinical signs of dermatitis, smaller lesion size, more epithelial hyperplasia and more granulation were found in skin biopsies from mice receiving anti-TNF compared with PBS controls. However, both CTLA4 Ig and anti-TNF therapy tended to prolong the healing time, although this finding was not statistically significant. Serum MCP-1 levels were elevated in the anti-TNF group relative to the CTLA4 Ig and PBS groups, whereas IL-6 levels were higher in PBS controls than in the other two groups. Both anti-TNF and CTLA4 Ig treatments tended to down-regulate the necrosis/apoptosis ratio in the locally infected skin tissue. Importantly, no tangible difference was found in the bacterial burden among groups.

Conclusion

Both CTLA4 Ig and anti-TNF therapies attenuate disease severity but may prolong the healing time required for S. aureus skin infections. Neither treatment has an impact on bacterial clearance in skin tissues.

Re-administration of abatacept for the control of articular symptoms of rheumatoid arthritis during anti-tuberculous therapy

This case report describes the re-administration of abatacept to successfully reduce the articularsymptoms of a patient with rheumatoid arthritisduring the intensive phase of anti-tuberculous therapy. A 75-year-old man developed active pulmonary tuberculosis during the administration of abatacept for rheumatoid arthritis. The patient experienced a paradoxical reaction and exacerbation of rheumatoid arthritis that caused us to discontinue the abatacept. Later re-administration of abatacept along with anti-tuberculosis treatment led to well-controlled rheumatoid arthritis without exacerbation of the tuberculosis. This case shows that re-administration of abatacept may be much safer than TNF inhibitor to treat patients who are infected with mycobacteria during thetreatment of immunological diseases such asrheumatoid arthritiswith biological agents.

Controlled Mycobacterium tuberculosis infection in mice under treatment with anti-IL-17A or IL-17F antibodies, in contrast to TNFα neutralization

Antibodies targeting IL-17A or its receptor IL-17RA show unprecedented efficacy in the treatment of autoimmune diseases such as psoriasis. These therapies, by neutralizing critical mediators of immunity, may increase susceptibility to infections. Here, we compared the effect of antibodies neutralizing IL-17A, IL-17F or TNFα on murine host responses to Mycobacterium tuberculosis infection by evaluating lung transcriptomic, microbiological and histological analyses. Coinciding with a significant increase of mycobacterial burden and pathological changes following TNFα blockade, gene array analyses of infected lungs revealed major changes of inflammatory and immune gene expression signatures 4 weeks post-infection. Specifically, gene expression associated with host-pathogen interactions, macrophage recruitment, activation and polarization, host-antimycobacterial activities, immunomodulatory responses, as well as extracellular matrix metallopeptidases, were markedly modulated by TNFα blockade. IL-17A or IL-17F neutralization elicited only mild changes of few genes without impaired host resistance four weeks after M. tuberculosis infection. Further, the absence of both IL-17RA and IL-22 pathways in genetically deficient mice did not profoundly compromise host control of M. tuberculosis over a 6-months period, ruling out potential compensation between these two pathways, while TNFα-deficient mice succumbed rapidly. These data provide experimental confirmation of the low clinical risk of mycobacterial infection under anti-IL-17A therapy, in contrast to anti-TNFα treatment.

Predictive risk factors of serious infections in patients with rheumatoid arthritis treated with abatacept in common practice: results from the Orencia and Rheumatoid Arthritis (ORA) registry

OBJECTIVES

Little data are available regarding the rate and predicting factors of serious infections in patients with rheumatoid arthritis (RA) treated with abatacept (ABA) in daily practice. We therefore addressed this issue using real-life data from the Orencia and Rheumatoid Arthritis (ORA) registry.

METHODS

ORA is an independent 5-year prospective registry promoted by the French Society of Rheumatology that includes patients with RA treated with ABA. At baseline, 3 months, 6 months and every 6 months or at disease relapse, during 5 years, standardised information is prospectively collected by trained clinical nurses. A serious infection was defined as an infection occurring during treatment with ABA or during the 3 months following withdrawal of ABA without any initiation of a new biologic and requiring hospitalisation and/or intravenous antibiotics and/or resulting in death.

RESULTS

Baseline characteristics and comorbidities: among the 976 patients included with a follow-up of at least 3 months (total follow-up of 1903 patient-years), 78 serious infections occurred in 69 patients (4.1/100 patient-years). Predicting factors of serious infections: on univariate analysis, an older age, history of previous serious or recurrent infections, diabetes and a lower number of previous anti-tumour necrosis factor were associated with a higher risk of serious infections. On multivariate analysis, only age (HR per 10-year increase 1.44, 95% CI 1.17 to 1.76, p=0.001) and history of previous serious or recurrent infections (HR 1.94, 95% CI 1.18 to 3.20, p=0.009) were significantly associated with a higher risk of serious infections.

CONCLUSIONS

In common practice, patients treated with ABA had more comorbidities than in clinical trials and serious infections were slightly more frequently observed. In the ORA registry, predictive risk factors of serious infections include age and history of serious infections.

CTLA4 Immunoglobulin but Not Anti-Tumor Necrosis Factor Therapy Promotes Staphylococcal Septic Arthritis in Mice

BACKGROUND

The development of biologics has greatly increased the quality of life and the life expectancy of many patients with rheumatoid arthritis. However, a large number of these patients have an increased risk of developing serious infections. The aim of this study was to examine differential effects of anti-tumor necrosis factor (TNF) treatment and CTLA4 immunoglobulin (Ig) treatment on both immunological response and host defense in a murine model of septic arthritis.

METHODS

Abatacept (CTLA4-Ig), etanercept (anti-TNF), or phosphate-buffered saline were given to NMRI mice intravenously inoculated with Staphylococcus aureus. The clinical course of septic arthritis and histopathological and radiological changes of joints were compared among the groups.

RESULTS

Mice receiving CTLA4-Ig treatment had more-severe septic arthritis, compared with controls and mice receiving anti-TNF treatment. Anti-TNF treatment led to more-severe weight loss and kidney abscesses, as well as a higher bacterial burden in the kidneys. Mice receiving CTLA4-Ig therapy had lower serum levels of interleukin 4, whereas mice receiving anti-TNF therapy had higher levels of TNF-α. Both iNOS and arginase-1 expression were reduced in peritoneal macrophages from mice receiving CTLA4-Ig, compared with expression in the anti-TNF group.

CONCLUSIONS

CTLA4-Ig therapy significantly increased the susceptibility to S. aureus septic arthritis in mice, whereas anti-TNF therapy deteriorated host bacterial clearance, resulting in more-severe weight loss and kidney abscesses.

Antibiotic-killed Staphylococcus aureus induces destructive arthritis in mice

OBJECTIVE

Permanent reduction in joint function is a severe postinfectious complication in patients with Staphylococcus aureus septic arthritis. We undertook this study to determine whether this reduction in joint function might be caused by persistent joint inflammation after the adequate eradication of bacteria by antibiotics.

METHODS

After intraarticular injection of cloxacillin-killed S aureus into mouse knee joints, we investigated whether antibiotic-killed S aureus induced joint inflammation and elucidated the molecular and cellular mechanisms of this type of arthritis.

RESULTS

Intraarticular injection of antibiotic-killed S aureus induced mild-to-moderate synovitis and bone erosions that lasted for a minimum of 14 days. Compared with wild-type animals, mice deficient in tumor necrosis factor receptor type I (TNFRI), receptor for advanced glycation end products (RAGE), or Toll-like receptor 2 (TLR-2) had a significantly reduced frequency and severity of synovitis. Combined depletion of monocytes and neutrophils also resulted in a significantly lower frequency of synovitis. Among bacterial factors, insoluble cell debris played a more important role than bacterial DNA or soluble components in inducing joint inflammation. Importantly, anti-TNF therapy abrogated joint inflammation induced by antibiotic-killed S aureus.

CONCLUSION

Antibiotic-killed S aureus induced and maintained joint inflammation mediated through TLR-2, TNFRI, and RAGE. The cross-talk between neutrophils and monocytes is responsible for this type of arthritis. Anti-TNF therapy might be used as a novel strategy, in combination with antibiotics, to treat staphylococcal septic arthritis.

Bedfellows: mycobacteria and rheumatoid arthritis in the era of biologic therapy

In modern times a relationship between tuberculosis (TB) and rheumatoid arthritis (RA) has been firmly recognized, and is primarily attributable to the immunosuppressive therapies used to treat RA. Whereas TB can complicate the successful management of RA, nontuberculous mycobacteria have now perhaps become as important as (if not more so than) TB in the setting of RA, and can represent an even greater challenge to the rheumatologist wishing to use immunosuppressive therapies. This article reviews our most recent understanding of the epidemiological and clinical aspects of mycobacterial disease as it relates to RA, and the existing and emerging immunosuppressive therapies used to treat this disease.

Overview of safety of non-biologic and biologic DMARDs

Safety data come from a number of sources. Randomized clinical trials tend to be relatively short, exclude patients with significant comorbidity, have limited numbers of subjects and are primarily powered for efficacy. The most useful post-marketing data come from large national registries, such as Britain's BSRBR, Sweden's ARTIS, Germany's RABBIT, France's DANBIO, Spain's BIODASER and North America's CORRONA. Among the most commonly used non-biologic DMARDs, MTX is associated with risks of hepatotoxicity and cytopenia, as well as pneumonitis, particularly during the first year of treatment. Regarding TNF inhibitors, there is an increased risk of infection (including serious infections) by bacterial pathogens, atypical fungi and opportunistic pathogens. When possible, pneumococcal and influenza vaccines should be given before initiation of treatment with any biologic DMARD. Screening for latent tuberculosis is recommended for all TNF inhibitors, and has been shown to reduce the risk of reactivation. Evidence from registries suggests that there is no increased risk of solid tumours with TNF inhibitor treatment; however, non-melanoma skin cancers are more common. Specific risks with other biologic DMARDs include gastrointestinal perforation with tocilizumab, progressive multifocal leucoencephalopathy with rituximab and pulmonary infections with abatacept. Overall, the safety of biologic and non-biologic DMARDs appears to be reasonable, particularly compared with the risks associated with the disease itself.

Tuberculosis in CBA/J mice

Tuberculosis (TB) develops in 5% to 10% of people infected with Mycobacterium tuberculosis (M.tb), but we do not understand how TB develops. CBA/J mice may model these events, as sick mice share features with TB patients, including weight loss, M.tb growth, extensive granulomatous infiltrates, neutrophils, necrosis, and fibrosis. Here, M.tb-infected CBA/J mice were categorized clinically: those with no signs or those with 10% weight loss to determine whether clinical state was associated with lung lesions. The type and distribution of infiltrates (granulomatous with lymphoid aggregates and scattered neutrophils) were similar in mice with weight loss and in mice with no signs. The amount of infiltration and neutrophil foci were higher in mice with weight loss than in mice with no clinical signs. Necrosis and fibrosis were only identified in mice that lost weight. Our results suggest that CBA/J mice may be useful to determine if and how neutrophils contribute to TB disease progression in mouse models.

Infections and biologic therapy in rheumatoid arthritis: our changing understanding of risk and prevention

Patients with rheumatoid arthritis are at higher risk for serious infections and death from infection than the general public. Prednisone and biologic agents increase this risk, although the risk associated with biologics can be mitigated when such agents act as prednisone-sparing therapies. Some of the important causes of infectious morbidity in this setting are preventable with screening (eg, tuberculosis) or vaccination (eg, herpes zoster).

Abatacept use in rheumatoid arthritis: evidence review and recommendations

OBJECTIVE

To review the clinical evidence on abatacept and to formulate recommendations in order to clear up points related to its use in rheumatology.

METHOD

An expert panel of rheumatologists objectively summarized the evidence on the mechanism of action, practicalities, effectiveness and safety of abatacept, and formulated recommendations following a literature review. The level of evidence and degree of recommendation was established.

RESULTS

The document presents 21 statements focused on evidence or recommendations on abatacept (14 evidence summaries and 9 recommendations). The level of evidence was 2b or higher according to the Oxford Centre for Evidence-Based Medicine scale on 14 occasions. The degree of the recommendation was A in two recommendations, C in one, and D in the rest. It was considered important to make recommendations on aspects with lower levels of evidence.

CONCLUSIONS

This is a practical document to supplement the summary of product characteristics.

Concordance of preclinical and clinical pharmacology and toxicology of therapeutic monoclonal antibodies and fusion proteins: cell surface targets

Monoclonal antibodies (mAbs) and fusion proteins directed towards cell surface targets make an important contribution to the treatment of disease. The purpose of this review was to correlate the clinical and preclinical data on the 15 currently approved mAbs and fusion proteins targeted to the cell surface. The principal sources used to gather data were: the peer reviewed Literature; European Medicines Agency 'Scientific Discussions'; and the US Food and Drug Administration 'Pharmacology/Toxicology Reviews' and package inserts (United States Prescribing Information). Data on the 15 approved biopharmaceuticals were included: abatacept; abciximab; alefacept; alemtuzumab; basiliximab; cetuximab; daclizumab; efalizumab; ipilimumab; muromonab; natalizumab; panitumumab; rituximab; tocilizumab; and trastuzumab. For statistical analysis of concordance, data from these 15 were combined with data on the approved mAbs and fusion proteins directed towards soluble targets. Good concordance with human pharmacodynamics was found for mice receiving surrogates or non-human primates (NHPs) receiving the human pharmaceutical. In contrast, there was poor concordance for human pharmacodynamics in genetically deficient mice and for human adverse effects in all three test systems. No evidence that NHPs have superior predictive value was found.

Choice of Biologic Therapy for Patients with Rheumatoid Arthritis: The Infection Perspective

Biologicals revolutionized the treatment of Rheumatoid Arthritis (RA). The targeted suppression of key inflammatory pathways involved in joint inflammation and destruction allows better disease control, which, however, comes at the price of an elevated infection risk due to relative immunosuppression. The disease-related infection risk and the infection risk associated with the use of TNF-α inhibitors (infliximab, adalimumab, etanercept, golimumab and certolizumab pegol), rituximab, abatacept and tocilizumab are discussed. Risk factors clinicians need to take into account when selecting the most appropriate biologic therapy for RA patients, as well as precautions and screening concerning a number of specific infections, such as tuberculosis, intracellular bacterial infections, reactivation of chronic viral infections and HIV are reviewed.

Inhibition of T cells provides protection against early invasive pneumococcal disease

Infections caused by Streptococcus pneumoniae are major causes of morbidity and mortality, which are in part mediated by immune cell-dependent mechanisms. Yet, the specific contributions of individual cell types to immunopathology are only partially understood. T cells are well characterized with respect to their function in protective humoral immune responses; however, their roles during early stages of infection and invasive pneumococcal disease (IPD) are less well defined. Using a mouse model of pneumococcal sepsis, we found that CD4(+) T cells were recruited to the lung as early as 12 h after intranasal infection. Recruitment was accompanied by upregulation of CD69 and B7-H1, reflecting T-cell activation. Unexpectedly, major histocompatibility complex (MHC) class II-deficient mice, which lack CD4(+) T cells, displayed an increased survival despite comparable bacterial titers in the blood, spleen, and lung. The higher survival correlated with a lower cytokine and chemokine response upon S. pneumoniae challenge in MHC class II-deficient mice, suggesting that inflammation may contribute to the mortality of IPD. Comparable to the case for MHC class II-deficient mice, antibody-mediated depletion of CD4(+) T cells and drug-induced inhibition of T-cell function with cyclosporine, or interference with T-cell activation using CTLA4-immunoglobulin (Abatacept), led to significant increases in survival during IPD. Our results reveal an important and adverse role of CD4(+) T cells in the pathogenesis of IPD and suggest that modulation of T-cell activation during early phases of S. pneumoniae invasive infection may provide a therapeutic option.

Abatacept in the treatment of rheumatoid arthritis

Rheumatoid arthritis (RA) is a chronic inflammatory arthritis affecting 1% of the population. The immunologic dysfunction underlying this immune disorder is complex and intricate with the involvement of various immune cells as well as cytokines and surface molecules. While inhibition of TNF-alpha has changed the outlook of patients with this disorder, it regulates only one aspect of the inflammatory cascade associated with RA. This is corroborated by experience in the clinic, where a significant proportion of the patients do not have clinical benefit with such therapies. Furthermore, a number of patients experience blunting of the initial therapeutic benefits of TNF-alpha-targeted therapies. Thus, a different approach to regulate the immune dysfunction associated with RA is necessary. T cells are considered important in the pathogenesis of RA and abatacept, a fusion protein, was developed to abolish the activation of the T cell by blocking its interaction with the antigen-presenting cell. Abatacept has demonstrated promising clinical improvements in patients with RA. Although clinical experience with this new drug is limited and its mechanism of action remains to be understood, the data on the safety profile are reassuring.

Infectious complications of biological therapy

PURPOSE OF REVIEW

Although the remarkable efficacy of biological therapy has resulted in significant success in rheumatic disease management, susceptibility to infections remains a concern. Here we review the latest publications on infectious complications of biological therapy in rheumatic diseases.

RECENT FINDINGS

The recent data on anti-tumor necrosis factor agents show encouraging results in relation to infections. The majority of the infections are minor, and opportunistic infections including tuberculosis are rare. The incidence of infections decreases with time on biologic therapy. Vaccination is effective while on biological agents, although live vaccines should be avoided. Biologic therapy in the setting of HIV, HCV and HBV continues to be studied, but data are accumulating in support of a favorable safety profile. There are degrees of differential susceptibility to infection across the rheumatic diseases, which should be taken into account in weighing the infectious risks of biologics in the respective diseases.

SUMMARY

Biological medications have a favorable safety profile but continued vigilance is appropriate. Most infectious reported episodes are minor and the risk of infection appears to decrease with duration of treatment.

Latent infection and tuberculosis disease in rheumatoid arthritis patients

New drug classes, biologics, have been developed over the past 10 years based on human or chimeric antibodies against cytokines or receptors with pivotal roles in the inflammatory pathways of immune-mediated inflammatory disease. Anti-tumor necrosis factor agents carry the largest infection risk of all the biologics, predisposing patients to mycobacterial infections. Patients receiving biologics are at higher risk for developing tuberculosis. New cases of tuberculosis or reactivation of latent tuberculosis infections may occur during the course of treatment, so a high level of vigilance is highly recommended.

Efficacy, safety, and tolerability of abatacept in the management of rheumatoid arthritis

The management of rheumatoid arthritis (RA) has undergone an impressive transformation over the past few decades. Further understanding of the pathophysiology of the disease process has resulted in the development of biologic agents that target proinflammatory cytokines and both B and T lymphocytes. By blocking an important costimulatory pathway, abatacept leads to a dramatic reduction in T cell stimulation and proliferation. Multiple clinical trials have revealed consistent benefit with regards to clinical and radiographic efficacy, quality of life, and disability in patients suffering from RA who have had inadequate responses to methotrexate or tumor necrosis factor inhibitors. The possibility of remission when used early in the disease course has also been demonstrated. Importantly, abatacept has been very well tolerated with a low rate of serious infections and no apparent increase in malignancies to date. Continued surveillance of the benefits and risks will help to better define its place amongst the other biologic agents in the treatment of RA.

B7 costimulation is critical for host control of chronic Mycobacterium tuberculosis infection

Although much is understood regarding the role of B7/CD28 family of costimulatory molecules in regulating host resistance in the context of several pathogens, analogous information with Mycobacterium tuberculosis is lacking. To address the requirements of B7-mediated costimulation in host resistance against tuberculosis, mice deficient in both B7.1 and B7.2 (B7DKO) were aerosol infected with M. tuberculosis Erdman and disease progression was monitored. We report herein that B7DKO mice are initially able to contain the bacterial load in the lung, but exhibit enhanced susceptibility during chronic infection. Despite the early control of bacterial replication, B7DKO mice essentially start off with compromised Th1 immunity and slower granulomatous response in the lung, characterized by markedly reduced lymphocytic infiltration. As the infection progresses from acute phase to the chronic phase, the nascent granulomas in the B7DKO lungs never fully achieve the architecture of granulomas developing in wild-type mice. Instead, lesions spread progressively to involve much of the lung in the B7DKO mice, ultimately leading to necrosis. Thus, early control of M. tuberculosis growth in the lung can occur in the absence of B7 costimulation and is less dependent on Th1 immunity and formation of a granulomatous structure. However, B7 costimulation is critical for long-term containment of infection within lung granulomas. These findings suggest that the use of costimulation-based immunomodulators may have significant repercussions on the induction of host protective immunity against tuberculosis.

The risk of infections with biologic therapies for rheumatoid arthritis

OBJECTIVES

To assess the risk of serious and nonserious bacterial and viral infections associated with the use of biologic therapy (abatacept, adalimumab, anakinra, etanercept, infliximab, and rituximab) in patients with rheumatoid arthritis (RA).

METHODS

Information was derived from PubMed, EMBASE, and the Cochrane clinical trials register and database of systematic reviews and relevant congress abstracts up to and including February 2008.

RESULTS

Compared with the general population, patients with RA have a heightened risk of infection, including tuberculosis. Long-term clinical trials and postmarketing studies indicate that anakinra and the tumor necrosis factor (TNF) inhibitors are associated with an increased risk of infections versus conventional disease-modifying antirheumatic drugs (DMARDs), especially early in the course of treatment. The most common sites of infection are the respiratory tract (including pneumonia), skin and soft tissue, and the urinary tract. The risk of tuberculosis also appears higher with TNF inhibitors (in particular, infliximab) versus DMARDs, although this can be reduced by screening and prophylaxis. TNF inhibitors do not appear to significantly increase the risk of reactivating chronic viral infections. Influenza and pneumococcal vaccinations are generally effective in the face of TNF inhibitors or abatacept. Available data suggest that the risk of infections and serious infections with abatacept and rituximab may be similar to that of the TNF inhibitors. To date, there have been no reports from clinical trials of increased tuberculosis or opportunistic infections with abatacept or rituximab.

CONCLUSIONS

All marketed TNF inhibitors for compared to control RA appear to increase the risk of serious and nonserious infections compared with DMARDs. Although suggestive, data for abatacept and rituximab are less definitive and longer periods of patient exposure to these agents are needed before an assessment of their risks can be made.