Successful treatment of macrophage activation syndrome complicating adult Still disease with anakinra

Efficacy and safety of therapies for Still's disease and macrophage activation syndrome (MAS): a systematic review informing the EULAR/PReS guidelines for the management of Still's disease

OBJECTIVES

To analyse the efficacy and safety of treatments for Still's disease and macrophage activation syndrome (MAS).

METHODS

Medline, Embase and Cochrane Library were searched for clinical trials (randomised, randomised controlled trial (RCT), controlled and clinical controlled trial (CCT)), observational studies (retrospective, longitudinal observational retrospective (LOR), prospective and longitudinal observational prospective (LOP)) and systematic reviews (SRs), in which the populations studied were patients with Still's disease and MAS. The intervention was any pharmacological treatment (approved or under evaluation) versus any comparator drug or placebo, and as outcomes, any relevant efficacy and safety event. The risk of bias (RoB) was assessed with the Cochrane RoB and AMSTAR-2 (Assessing the Methodological Quality of Systematic Reviews-2, version 2) for SRs.

RESULTS

128 full texts were included: 25 RCTs, 1 CCT, 11 SRs published after 2013 and 91 LOP/LOR studies. In Still's disease, interleukin (IL)-1 inhibitors (IL-1i) and IL-6R inhibitors (IL-6i) were the most studied drugs. Two meta-analyses on RCTs showed an OR, to achieve an ARC50 response rate, of 6.02 (95% CI 2.24 to 21.36) and 8.08 (95% CI 1.89 to 34.57) for IL-1i and IL-6Ri, respectively. Retrospective studies showed that early initiation of IL-1i or IL-6i was associated with high rates of clinically inactive disease. In MAS, GCs were employed in all patients, often associated with ciclosporin and/or anakinra. Rates of complete response were reported, with a range from 53% to 100%. Emapalumab was the only drug tested in a CCT, with a complete response of 93%.

CONCLUSION

IL-1i and IL-6Ri show the highest level of efficacy in the treatment of Still's disease. For MAS, IL-1 and interferon-γ inhibition appear to be effective on a background of high-dose glucocorticoids.

Adult-Onset Still's Disease (AOSD): Advances in Understanding Pathophysiology, Genetics and Emerging Treatment Options

Adult-onset Still's disease (AOSD) is a multisystemic complex disorder clinically characterised by episodes of spiking fever, evanescent rash, polyarthritis or diffuse arthralgias; multiorgan involvement may develop according to the hyper-inflammatory extent. The pathogenesis of AOSD is not completely recognised. The central role of macrophage activation, which results in T helper 1 (Th1) cell cytokine activation, is well established. Pro-inflammatory cytokines such as interleukin (IL)-1, IL-6 and IL-18 play a fundamental role in disease onset and progression. The disease may develop in both children and adults with overlapping clinical features, and although several subsets depending on the clinical manifestations and the cytokines expressed have been identified, the dichotomy between systemic juvenile idiopathic arthritis (sJIA) and AOSD nowadays has been overcome, and the pathology is considered a disease continuum between ages. Various therapeutic approaches have been evaluated thus far, and different compounds are under assessment for AOSD treatment. Historically, glucocorticoids have been employed for treating systemic manifestations of Still's disease, while conventional synthetic disease modifying anti-rheumatic drugs (csDMARDs) demonstrated efficacy in controlling the articular manifestations. Currently, biological (b) DMARDs are widely employed; IL-1 inhibitors such as anakinra and canakinumab have proven to have high efficacy and an excellent safety profile and the anti-IL-6 tocilizumab is approved for sJIA, with several trials and longitudinal studies confirming its efficacy and safety. Moreover, in the light of the 'window of opportunity', new evidence showed that the earlier these treatments are initiated, the sooner clinical inactivity can be achieved. Other treatment options are being considered since several molecules involved in the disease pathophysiology can be targeted through various mechanisms. This review will provide a broad overview of AOSD pathophysiology, insights into specific organ manifestations and the currently available treatments with the identification of potential therapeutic targets involved in AOSD pathogenesis will be outlined.

IL-1 Family Blockade in Cytokine Storm Syndromes

Interleukin-1 is a prototypic proinflammatory cytokine that is elevated in cytokine storm syndromes (CSSs), such as secondary hemophagocytic lymphohistiocytosis (sHLH) and macrophage activation syndrome (MAS). IL-1 has many pleotropic and redundant roles in both innate and adaptive immune responses. Blockade of IL-1 with recombinant human interleukin-1 receptor antagonist has shown efficacy in treating CSS. Recently, an IL-1 family member, IL-18, has been demonstrated to be contributory to CSS in autoinflammatory conditions, such as in inflammasomopathies (e.g., NLRC4 mutations). Anecdotally, recombinant IL-18 binding protein can be of benefit in treating IL-18-driven CSS. Lastly, another IL-1 family member, IL-33, has been postulated to contribute to CSS in an animal model of disease. Targeting of IL-1 and related cytokines holds promise in treating a variety of CSS.

A Novel Therapy for a Rare Condition: Continuous Anakinra Infusion for a Patient With Macrophage Activation Syndrome

Macrophage activation syndrome (MAS) is a type of hemophagocytic lymphohistiocytosis (HLH), which occurs due to excessive stimulation of the immune system. Common precipitants of MAS include disseminated infection or underlying rheumatologic disorders such as adult-onset Still's disease which is characterized as an inflammatory arthritis with daily fevers and a salmon-colored rash. We present a case of a patient with probable adult-onset Still's disease and subsequent disseminated cytomegalovirus (CMV) infection, who met the criteria for MAS based on the presence of a fever, cytopenia in multiple cell lines, elevated ferritin, presence of hemophagocytosis on bone marrow, low fibrinogen, and mild splenomegaly on physical exam. The patient responded to treatment with continuous anakinra infusion and ganciclovir for treatment of CMV. Though cytotoxic medications such as etoposide have traditionally been considered first-line treatment for HLH/MAS, interleukin-1 inhibitors such as anakinra are emerging as aless cytotoxic alternative.

Use of Intravenous Anakinra for Management of Pediatric Cytokine Storm Syndromes at an Academic Medical Center

Background: Off-label intravenous (IV) route of anakinra is increasingly recognized to enable higher and faster maximal plasma concentrations than subcutaneous route for treatment of cytokine storm syndromes. Objective: To describe off-label indications of IV anakinra, corresponding dosing and safety profiles, particularly during the coronavirus disease 19 (COVID-19) pandemic. Methods: A retrospective, single-cohort study was conducted at an academic medical center to evaluate use of IV anakinra in hospitalized pediatric patients (age ≤21 years). Institutional Review Board review was considered exempt. The primary endpoint was the primary indication(s) for IV anakinra. The key secondary endpoints were dosing of IV anakinra, previous immunomodulatory therapies, and adverse events. Results: Of 14 pediatric patients, 8 (57.1%) received IV anakinra for treatment of multisystem inflammatory syndrome in children (MIS-C) associated with COVID-19, whereas 3 and 2 were treated for hemophagocytic lymphohistiocytosis (HLH) and flares of systemic onset juvenile idiopathic arthritis (SoJIA), respectively. The initial dosing regimen of IV anakinra for MIS-C associated with COVID-19 was a median dose of 2.25 mg/kg/dose with a median dosing interval of 12 hours for a median initial treatment duration of 3.5 days. Eleven (78.6%) patients received previous immunomodulatory therapies (IV immune globulin [n = 10; 71.4%] and steroids [n = 9; 64.3%]). No adverse drug events were documented. Conclusion: IV anakinra was used off-label for treatment of MIS-C associated with COVID-19, HLH and SoJIA flares in critically ill patients with no adverse drug events documented. This study helped ascertain the off-label indications of IV anakinra and corresponding patient characteristics.

The 'cytokine storm': molecular mechanisms and therapeutic prospects

Cytokine storm syndrome (CSS) has generally been described as a collection of clinical manifestations resulting from an overactivated immune system. Cytokine storms (CSs) are associated with various pathologies, as observed in infectious diseases, certain acquired or inherited immunodeficiencies and autoinflammatory diseases, or following therapeutic interventions. Despite the role of CS in tissue damage and multiorgan failure, a systematic understanding of its underlying molecular mechanisms is lacking. Recent studies demonstrate a positive feedback loop between cytokine release and cell death pathways; certain cytokines, pathogen-associated molecular patterns (PAMPs), and damage-associated molecular patterns (DAMPs), can activate inflammatory cell death, leading to further cytokine secretion. Here, we discuss recent progress in innate immunity and inflammatory cell death, providing insights into the cellular and molecular mechanisms of CSs and therapeutics that might quell ensuing life-threatening effects.

Silencing the cytokine storm: the use of intravenous anakinra in haemophagocytic lymphohistiocytosis or macrophage activation syndrome

The term cytokine storm syndromes describes conditions characterised by a life-threatening, fulminant hypercytokinaemia with high mortality. Cytokine storm syndromes can be genetic or a secondary complication of autoimmune or autoinflammatory disorders, infections, and haematological malignancies. These syndromes represent a key area of interface between rheumatology and general medicine. Rheumatologists often lead in management, in view of their experience using intensive immunosuppressive regimens and managing cytokine storm syndromes in the context of rheumatic disorders or infection (known as secondary haemophagocytic lymphohistiocytosis or macrophage activation syndrome [sHLH/MAS]). Interleukin (IL)-1 is pivotal in hyperinflammation. Anakinra, a recombinant humanised IL-1 receptor antagonist, is licenced at a dose of 100 mg once daily by subcutaneous injection for rheumatoid arthritis, systemic juvenile idiopathic arthritis, adult-onset Still's disease, and cryopyrin-associated periodic syndromes. In cytokine storm syndromes, the subcutaneous route is often problematic, as absorption can be unreliable in patients with critical illness, and multiple injections are needed to achieve the high doses required. As a result, intravenous anakinra is used in clinical practice for sHLH/MAS, despite this being an off-licence indication and route of administration. Among 46 patients admitted to our three international, tertiary centres for sHLH/MAS and treated with anakinra over 12 months, the intravenous route of delivery was used in 18 (39%) patients. In this Viewpoint, we describe current challenges in the management of cytokine storm syndromes and review the pharmacokinetic and safety profile of intravenous anakinra. There is accumulating evidence to support the rationale for, and safety of, intravenous anakinra as a first-line treatment in patients with sHLH/MAS. Intravenous anakinra has important clinical relevance when high doses of drug are required or if patients have subcutaneous oedema, severe thrombocytopenia, or neurological involvement. Cross-speciality management and collaboration, with the generation of international, multi-centre registries and biobanks, are needed to better understand the aetiopathogenesis and improve the poor prognosis of cytokine storm syndromes.

Macrophage Activation Syndrome Versus Hemophagocytic Lymphohistiocytosis: A Diagnostic Dilemma in a Patient With Still's Disease and Epstein-Barr Virus Viremia

Macrophage activation syndrome (MAS) and hemophagocytic lymphohistiocytosis (HLH) are two overlapping, potentially fatal syndromes classified by disorganization and malfunction of the immune system that results in wide spread inflammation and end-organ damage. We present the case of a 22-year-old female with both underlying adult-onset still’s disease and active Epstein-Barr virus (EVB) viremia who presented with criteria for MAS/HLH. She ultimately improved on an immunosuppressive regimen, and during follow-up was also found to be heterozygote carrier for a known genetic mutation that has been associated with “primary” HLH. This case thus highlights the clinical spectrum of HLH/MAS, the different treatment approaches, and the new investigations into the relationship between primary and secondary HLH.

Management of adult-onset Still's disease with interleukin-1 inhibitors: evidence- and consensus-based statements by a panel of Italian experts

BACKGROUND

Adult-onset Still's disease (AOSD) is a rare inflammatory condition characterized by fever, rash, and arthritis. Because of its rarity, clinical trials are inherently small and often uncontrolled. Our objective was to develop recommendations for the use of interleukin (IL)-1 inhibitors in the management of patients with AOSD, based on the best evidence and expert opinion.

METHODS

A panel of 10 experts (9 rheumatologists and 1 pediatrician) was established. The first step was dedicated to a comprehensive literature review and development of statements. Two separate literature searches were performed on the MEDLINE (Pubmed), EMBASE, and BIOSIS databases through April 2018 to identify (1) differences and similarities between AOSD and pediatric Still's disease (systemic juvenile idiopathic arthritis [SJIA]) and (2) the efficacy and safety of IL-1 inhibitors in AOSD treatment. In the second step, the statements were submitted in a Delphi process to a panel of 67 rheumatologists. Consensus threshold was set at 66%: positive, > 66% of voters selected scores 3 to 5; negative, > 66% of voters selected scores 1 or 2. In the third step, the voting results were analyzed, and the statements were finalized.

RESULTS

Eleven statements were developed. Forty-six of 67 rheumatologists (72%) participated in the Delphi process. A positive consensus was reached after the first round of voting and was full (> 95%) on the majority of statements. A large consensus was achieved in considering AOSD and SJIA as the same disease. The use of anti-IL-1 therapies in refractory patients was considered quite safe and effective both as the first and as a subsequent line of biologic treatment, especially in systemic patients. Because of the lack of head-to-head comparisons, a different profile of efficacy among IL-1 inhibitors could not be established. There was a large consensus that failure of the first IL-1 inhibitor does not preclude response to another one. The lack of studies comparing early versus late treatment did not allow to draw conclusions; however, data from SJIA suggest a better response in early treatment.

CONCLUSIONS

The Delphi method was used to develop recommendations that we hope will help clinicians in the management of patients with AOSD refractory to conventional therapies.

Macrophage activation syndrome in adults: recent advances in pathophysiology, diagnosis and treatment

Haemophagocytic lymphohistiocytosis (HLH) is a hyperinflammatory syndrome, which if not promptly treated, can lead rapidly to critical illness and death. HLH is termed macrophage activation syndrome (MAS) when associated with rheumatic disease (where it is best characterized in systemic JIA) and secondary HLH (sHLH) when associated with other triggers including malignancy and infection. MAS/sHLH is rare and coupled with its mimicry of other conditions, is underrecognized. These inherent challenges can lead to diagnostic and management challenges in multiple medical specialties including haematology, infectious diseases, critical care and rheumatology. In this review we highlight the pathogenesis of MAS/sHLH including its underlying triggers, key clinical features and diagnostic challenges, prognostic factors and current treatments in adults.

Macrophage activation syndrome complicating rheumatic diseases in adults: case-based review

Macrophage activation syndrome (MAS) is a life-threatening complication of rheumatologic diseases. Data regarding the clinical course, management and outcome of adults with MAS is limited. Therefore, we aimed to describe the clinical features, treatment and outcome of adult patients with MAS, and review the literature for previous cohorts. We retrospectively reviewed patients with MAS complicating rheumatologic diseases between the years 2007 and 2017. Through Pubmed, Medline and Scopus literature search we identified previous cases of adult patients with MAS. We identified 7 patients with MAS complicating rheumatologic diseases (5 females and 2 males). The median age of diagnosis was 32 (range 26-57) years. The median follow-up was 30 months (range 6.95-36.5) months. The underlying rheumatologic disease was adult onset Still's disease (AOSD) in 3 patients, systemic juvenile idiopathic arthritis (sJIA) in 2 patients, systemic lupus erythematosus (SLE) in 1 patient, and systemic vasculitis in 1 patient. Four patients developed MAS concurrently with the clinical development of the rheumatologic disease. All the patients were treated with systemic corticosteroids. Five patients were treated with cyclosporine A, one of which received combination therapy with anakinra, and one received tocilizumab. Two patients deceased during the hospitalization. We identified 92 patients from literature cohorts, 73 (79%) of them with AOSD. MAS developed concurrently with the underlying rheumatologic disease in 25 (27%) patients, and 30 (33%) patients deceased. Our cohort and previous cohorts demostrate that MAS often presents concurrently with the underlying rheumatologic disease and is associated with a high mortality rate. Further larger prospective studies are needed to determine the optimal management of MAS.

Complications of Treatments for Pediatric Rheumatic Diseases

Medications to treat children with rheumatic disease include disease-modifying antirheumatic drugs, glucocorticosteroids, and biologic response modifiers that target mediators and cells involved in autoimmunity and inflammation. Although usually well-tolerated, such medications have many possible side effects, of which primary care and emergency providers should be aware. Both disease and immunosuppression contribute to susceptibility to unusual and opportunistic infections, in addition to usual childhood infections for which these children should receive all applicable nonlive vaccines. Close coordination between the rheumatologist and other medical care providers is essential, because medication side effects, infections, and disease flares are difficult to distinguish, and may occur together.

Autoinflammatory disease in the lung

Ascertaining the dominant cell type driving an immunological disease is essential to understanding the causal pathology and, therefore, selecting or developing an effective treatment. Classifying immunological diseases in this way has led to successful treatment regimens for many monogenic diseases; however, when the dominant cell type is unclear and there is no obvious causal genetic mutation, then identifying the correct disease classification and appropriate therapy can be challenging. In this review we focus on pulmonary immunological diseases where an innate immune signature has been identified as a predominant aspect of the immunopathology. We describe the molecular pathology of 'autoinflammatory diseases of the lung' and propose that small molecule and biological therapies, including recombinant interleukin-1 receptor antagonist, that target key innate immune pathways, are likely be beneficial in the control of pulmonary and systemic inflammation in these conditions. In addition, the successful use of macrolide antibiotics to treat lung infections in these conditions further confirms that the innate immune system is the key conductor of inflammation in these pulmonary diseases, as there is a strong body of evidence that macrolides are able to modulate the NLRP3 inflammasome and interleukin-1β and interleukin-18 secretion, both of which are central players in the innate immune response. Throughout this review we highlight the published evidence of autoinflammatory disease in chronic obstructive pulmonary disease, bronchiectasis, cystic fibrosis and rheumatoid lung disease and suggest that the fundamental pathology of these diseases places them towards the autoinflammatory pole of the immunological disease continuum.

Epstein-Barr Virus and Hemophagocytic Lymphohistiocytosis

Epstein–Barr virus (EBV) is a ubiquitous virus that infects nearly all people worldwide without serious sequela. However, for patients who have genetic diseases which predispose them to the development of hemophagocytic lymphohistiocytosis (HLH), EBV infection is a life-threatening problem. As a part of a themed collection of articles on EBV infection and human primary immune deficiencies, we will review key concepts related to the understanding and treatment of HLH.

Macrophage Activation Syndrome Associated with Adult-Onset Still's Disease Successfully Treated with Anakinra

Macrophage activation syndrome (MAS) is a potentially fatal complication of Adult-Onset Still's disease (Still's disease). Whereas an increasing body of evidence supports interleukin-1 (IL-1) blockade as a promising treatment for Still's disease, whether it is therapeutic for MAS associated with Still's disease remains unclear. We report a 34-year-old Caucasian man with one-decade history of TNF-blockade-responsive seronegative arthritis who presented with abrupt onset of fever, serositis, bicytopenia, splenomegaly, hepatitis, and disseminated intravascular coagulation. Striking hyperferritinemia was noted without evidence of infection, malignancy, or hemophagocytosis on bone marrow biopsy. NK cells were undetectable in the peripheral blood, whereas soluble IL-2 receptor was elevated. His multiorgan disease resolved in association with methylprednisolone pulse therapy, Anakinra, and a tapering course of prednisone. This case reinforces the notion that Still's disease is inherently poised to manifest MAS as one of the clinical phenotypes by shedding light on the role of IL-1 underlying both Still's disease and related MAS.

Successful Tocilizumab Therapy for Macrophage Activation Syndrome Associated with Adult-Onset Still's Disease: A Case-Based Review

We report the case of a 71-year-old Japanese woman with adult-onset Still's disease (AOSD) in whom macrophage activation syndrome (MAS) developed despite therapy with oral high-dose prednisolone and intravenous methylprednisolone pulse therapy twice. She was successfully treated with tocilizumab (TCZ). Soon afterward, her fever ceased and high levels of both ferritin and C-reactive protein levels decreased. Her course was complicated by disseminated intravascular coagulation, cytomegalovirus infection, and Pneumocystis jirovecii pneumonia. After these were resolved, AOSD-associated MAS was well controlled. She was discharged on hospital day 87. Although biologics such as TCZ are becoming established for the treatment of AOSD, there is no recommended therapy for AOSD-associated MAS. Several biologics have been tried for this complication, but their efficacy and safety remain controversial. We reviewed reported cases of AOSD-associated MAS successfully treated with various biologics. TCZ initiation after adequate nonselective immunosuppressive therapy, such as methylprednisolone pulse therapy or a prednisolone-based combination of immunosuppressants, can be an effective treatment for AOSD-associated MAS. On the other hand, biologics given after insufficient immunosuppressive therapy may cause MAS. A strategy combining adequate immunosuppression and a biologic could be safe if special attention is given to adverse events such as opportunistic infections or biologic-associated MAS.

Interleukin-1 Receptor Blockade Is Associated With Reduced Mortality in Sepsis Patients With Features of Macrophage Activation Syndrome: Reanalysis of a Prior Phase III Trial

OBJECTIVE

To determine the efficacy of anakinra (recombinant interleukin-1 receptor antagonist) in improving 28-day survival in sepsis patients with features of macrophage activation syndrome. Despite equivocal results in sepsis trials, anakinra is effective in treating macrophage activation syndrome, a similar entity with fever, disseminated intravascular coagulation, hepatobiliary dysfunction, cytopenias, and hyperferritinemia. Hence, sepsis patients with macrophage activation syndrome features may benefit from interleukin-1 receptor blockade.

DESIGN

Reanalysis of deidentified data from the phase III randomized interleukin-1 receptor antagonist trial in severe sepsis.

SETTING

Multicenter study recruiting through 91 centers from 11 countries in Europe and North America.

PATIENTS

Sepsis patients with multiorgan dysfunction syndrome and/or shock (original study) were regrouped based on the presence or the absence of concurrent hepatobiliary dysfunction and disseminated intravascular coagulation as features of macrophage activation syndrome. The non-hepatobiliary dysfunction/disseminated intravascular coagulation group included patients with only hepatobiliary dysfunction, only disseminated intravascular coagulation, or neither.

INTERVENTION

Treatment with anakinra or placebo.

MEASUREMENTS AND MAIN RESULTS

Main outcome was 28-day mortality. Descriptive and comparative statistics were performed. Data were available for 763 adults from the original study cohort, randomized to receive either anakinra or placebo. Concurrent hepatobiliary dysfunction/disseminated intravascular coagulation was noted in 43 patients (5.6% of total; 18-75 years old; 47% women). The 28-day survival was similar in both anakinra and placebo-treated non-hepatobiliary dysfunction/disseminated intravascular coagulation patients (71.4% vs 70.8%; p = 0.88). Treatment with anakinra was associated with significant improvement in the 28-day survival rate in hepatobiliary dysfunction/disseminated intravascular coagulation patients (65.4% anakinra vs 35.3% placebo), with hazard ratio for death 0.28 (0.11-0.71; p = 0.0071) for the treatment group in Cox regression.

CONCLUSIONS

In this subgroup analysis, interleukin-1 receptor blockade was associated with significant improvement in survival of patients with sepsis and concurrent hepatobiliary dysfunction/disseminated intravascular coagulation. A prospective randomized trial using features of macrophage activation syndrome for mortality risk stratification should be undertaken to confirm the role of interleukin-1 blockage.

Successful Treatment with Intravenous Cyclophosphamide for Refractory Adult-Onset Still's Disease

We report a 64-year-old female case of intractable adult-onset Still's disease (AOSD). Initial high-dose steroid therapy combined with cyclosporin A was ineffective against macrophage-activation syndrome (MAS), which was accompanied by the systemic type of AOSD. Treatment for MAS with intravenous cyclophosphamide resulted in remission of AOSD and a reduction in the high doses of steroids. Efficacy of biologics against MAS in AOSD is unclear. Cyclophosphamide, a conventional cytotoxic agent, should be considered as one of the therapeutic options for refractory types of AOSD with MAS.

Cross talk between neuroregulatory molecule and monocyte: nerve growth factor activates the inflammasome

BACKGROUND

Increasing evidence points to a role for the extra-neuronal nerve growth factor (NGF) in acquired immune responses. However, very little information is available about its role and underlying mechanism in innate immunity. The role of innate immunity in autoimmune diseases is becoming increasingly important. In this study, we explored the contribution of pleiotropic NGF in the innate immune response along with its underlying molecular mechanism with respect to IL-1β secretion.

METHODS

Human monocytes, null and NLRP3 deficient THP-1 cell lines were used for this purpose. We determined the effect of NGF on secretion of IL-1β at the protein and mRNA levels. To determine the underlying molecular mechanism, the effect of NGF on NLRP1/NLRP3 inflammasomes and its downstream key protein, activated caspase-1, were evaluated by ELISA, immunoflorescence, flow cytometry, and real-time PCR.

RESULTS

In human monocytes and null THP-1 cell line, NGF significantly upregulates IL-1β at protein and mRNA levels in a caspase-1 dependent manner through its receptor, TrkA. Furthermore, we observed that NGF induces caspase-1 activation through NLRP1/NLRP3 inflammasomes, and it is dependent on the master transcription factor, NF-κB.

CONCLUSIONS

To best of our knowledge, this is the first report shedding light on the mechanistic aspect of a neuroregulatory molecule, NGF, in innate immune response, and thus enriches our understanding regarding its pathogenic role in inflammation. These observations add further evidence in favor of anti-NGF therapy in autoimmune diseases and also unlock a new area of research about the role of NGF in IL-1β mediated diseases.

Increased level of H-ferritin and its imbalance with L-ferritin, in bone marrow and liver of patients with adult onset Still's disease, developing macrophage activation syndrome, correlate with the severity of the disease

In this paper, we aimed to evaluate the levels of ferritin enriched in H subunits (H-ferritin) and ferritin enriched in L subunits (L-ferritin) and the cells expressing these 2 molecules, in the bone marrow (BM) and liver biopsies obtained from adult onset Still's disease (AOSD) patients who developed macrophage activation syndrome (MAS), and correlating these data with the severity of the disease. Twenty-one patients with MAS-associated AOSD underwent BM biopsy and among them, 9 patients with hepatomegaly and elevated liver enzymes underwent liver biopsy. All the samples were stained by both immunohistochemistry and immunofluorescence. A statistical analysis was performed to estimate the possible correlation among both H-ferritin and L-ferritin tissue expression and the clinical picture of the disease. Furthermore, the same analysis was performed to evaluate the possible correlation among the number of CD68/H-ferritin or CD68/L-ferritin positive cells and the clinical picture. Both immunohistochemical and immunofluorescence analysis demonstrated an increased tissue H-ferritin expression, in the BM and liver samples of our patients. This increased expression correlated with the severity of the disease. An inflammatory infiltrate, enriched in CD68 macrophages, expressing H-ferritin was observed in both the BM and the liver samples of our patients. Furthermore, we observed, that this increased number of CD68/H-ferritin positive cells significantly correlated with the severity of clinical picture and this specific BM infiltrate correlated with the mortality rate, reported in our cohort. Our data showed an imbalance between the levels of H- and L-ferritin in different organs of patients with MAS-associated AOSD and the evidence of a strong infiltrate of CD68/H-ferritin positive cells in the same organs. Furthermore, a strong correlation among both the tissue H-ferritin and the CD68/H-ferritin positive cells and the clinical picture was observed.

An expanding role for interleukin-1 blockade from gout to cancer

There is an expanding role for interleukin (IL)-1 in diseases from gout to cancer. More than any other cytokine family, the IL-1 family is closely linked to innate inflammatory and immune responses. This linkage is because the cytoplasmic segment of all members of the IL-1 family of receptors contains a domain, which is highly homologous to the cytoplasmic domains of all toll-like receptors (TLRs). This domain, termed "toll IL-1 receptor (TIR) domain," signals as does the IL-1 receptors; therefore, inflammation due to the TLR and the IL-1 families is nearly the same. Fundamental responses such as the induction of cyclo-oxygenase type 2, increased surface expression of cellular adhesion molecules and increased gene expression of a broad number of inflammatory molecules characterizes IL-1 signal transduction as it does for TLR agonists. IL-1β is the most studied member of the IL-1 family because of its role in mediating autoinflammatory disease. However, a role for IL-1α in disease is being validated because of the availability of a neutralizing monoclonal antibody to human IL-1α. There are presently three approved therapies for blocking IL-1 activity. Anakinra is a recombinant form of the naturally occurring IL-1 receptor antagonist, which binds to the IL-1 receptor and prevents the binding of IL-1β as well as IL-1α. Rilonacept is a soluble decoy receptor that neutralizes primarily IL-1β but also IL-1α. Canakinumab is a human monoclonal antibody that neutralizes only IL-1β. Thus, a causal or significant contributing role can be established for IL-1β and IL-1α in human disease.

Adult onset Still's disease (AOSD) in the era of biologic therapies: dichotomous view for cytokine and clinical expressions

Adult onset Still's disease (AOSD) is a rare inflammatory disorder characterized by hectic spiking fever, evanescent rash and joint involvement. Prognosis is highly variable upon disease course and specific involvements, ranging from benign and limited outcome to chronic destructive polyarthritis and/or life-threatening events in case of visceral complications or reactive hemophagocytic lymphohistiocytosis (RHL). AOSD remains a debatable entity at the frontiers of autoimmune diseases and autoinflammatory disorders. The pivotal role of macrophage cell activation leading to a typical Th1 cytokine storm is now well established in AOSD, and confirmed by the benefits using treatments targeting TNF-α, IL-1β or IL-6 in refractory patients. However, it remains difficult to determine predictive factors of outcome and to draw guidelines for patient management. Herein, reviewing literature and relying on our experience in a series of 8 refractory AOSD patients, we question nosology and postulate that different cytokine patterns could underlie contrasting clinical expressions, as well as responses to targeted therapies. We therefore propose to dichotomize AOSD according to its clinical presentation. On the one hand, 'systemic AOSD' patients, exhibiting the highest inflammation process driven by excessive IL-18, IL-1β and IL-6 production, would be at risk of life-threatening complications (such as multivisceral involvements and RHL), and would preferentially respond to IL-1β and IL-6 antagonists. On the other hand, 'rheumatic AOSD' patients, exhibiting pre-eminence of joint involvement driven by IL-8 and IFN-γ production, would be at risk of articular destructions, and would preferentially respond to TNF-α blockers.

Treating inflammation by blocking interleukin-1 in humans

IL-1 is a master cytokine of local and systemic inflammation. With the availability of specific IL-1 targeting therapies, a broadening list of diseases has revealed the pathologic role of IL-1-mediated inflammation. Although IL-1, either IL-1α or IL-1β, was administered to patients in order to improve bone marrow function or increase host immune responses to cancer, these patients experienced unacceptable toxicity with fever, anorexia, myalgias, arthralgias, fatigue, gastrointestinal upset and sleep disturbances; frank hypotension occurred. Thus it was not unexpected that specific pharmacological blockade of IL-1 activity in inflammatory diseases would be beneficial. Monotherapy blocking IL-1 activity in a broad spectrum of inflammatory syndromes results in a rapid and sustained reduction in disease severity. In common conditions such as heart failure and gout arthritis, IL-1 blockade can be effective therapy. Three IL-1blockers have been approved: the IL-1 receptor antagonist, anakinra, blocks the IL-1 receptor and therefore reduces the activity of IL-1α and IL-1β. A soluble decoy receptor, rilonacept, and a neutralizing monoclonal anti-interleukin-1β antibody, canakinumab, are also approved. A monoclonal antibody directed against the IL-1 receptor and a neutralizing anti-IL-1α are in clinical trials. By specifically blocking IL-1, we have learned a great deal about the role of this cytokine in inflammation but equally important, reducing IL-1 activity has lifted the burden of disease for many patients.

Interleukin-18, more than a Th1 cytokine

Together with IL-12 or IL-15, interleukin-18 (IL-18) plays a major role in the production of interferon-γ from T-cells and natural killer cells; thus, IL-18 is considered to have a major role in the Th1 response. However, without IL-12, IL-18 is proinflammatory in an IFNγ independent manner. IL-18 is a member of the IL-1 family of cytokines and similar to IL-1β, the cytokine is synthesized as an inactive precursor requiring processing by caspase-1 into an active cytokine. IL-18 is also present as an integral membrane protein but requires caspase-1 for full activity in order to induce IFNγ. Uniquely, unlike IL-1β, the IL-18 precursor is constitutively present in nearly all cells in healthy humans and animals. The activity of IL-18 is balanced by the presence of a high-affinity, naturally occurring IL-18 binding protein (IL-18BP). In humans, increased disease severity can be associated with an imbalance of IL-18 to IL-18BP such that the levels of free IL-18 are elevated in the circulation. Increasing number of studies have expanded the role of IL-18 in mediating inflammation in animal models of disease using the IL-18BP, IL-18 deficient mice, neutralization of IL-18 or deficiency in the IL-18 receptor alpha chain. A role for IL-18 has been implicated in several autoimmune diseases, myocardial function, emphysema, metabolic syndromes, psoriasis, inflammatory bowel disease, macrophage activation syndrome, sepsis and acute kidney injury, although paradoxically, in some models of disease, IL-18 is protective. The IL-18BP has been used safely in humans and clinical trials of IL-18BP as well as neutralizing anti-IL-18 antibodies are being tested in various diseases.