Macrophage Activation Syndrome in Patients with Systemic Juvenile Idiopathic Arthritis under Treatment with Tocilizumab

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.

Macrophage activation syndrome in patients with systemic juvenile idiopathic arthritis on anti-interleukin-1 or -6 therapy

OBJECTIVES

The aim of this study is to investigate the effect of anti-interleukin (IL)-1/-6 biologics on systemic juvenile idiopathic arthritis (sJIA)-associated macrophage activation syndrome (MAS).

METHODS

Demographic, clinical and laboratory data of patients followed up with a diagnosis of sJIA-associated MAS assessed from sixteen paediatric rheumatology centres across the country. The clinical and laboratory features of MAS developing while on biological drugs were compared with those without this treatment.

RESULTS

One hundred and sixty-two patients were included in the study. Forty-five of the MAS events were detected under the effect of anti-IL-1/-6 biologics, while the patients experiencing the remaining 155 events have not received biological treatment in the last three months. Platelet count [128 (72-232) vs 199 (130-371) 109/l], ferritin level on admission [1107 (676-2050) vs 2863 (1193-9562) ng/ml], C-reactive protein level [15.4 (2.9-56) vs 90 (32-160) mg/l], erythrocyte sedimentation rate [13 (3-36) vs 43.5 (13-77) mm/h] and fever duration [5 (4-7.5) vs 10 (7-14.3) days] were found lower in the group under the impact of anti-IL-1/-6 biologics. Among patients treated with biologics, 26.6% did not meet the published 2016 MAS classification criteria at presentation. The rates of hepatomegaly and splenomegaly were relatively lower in the canakinumab-treated group when compared with those receiving other biologicals or to patients, not on biologicals.

CONCLUSION

Anti-IL-1/-6 therapies can mask the clinical and laboratory features of MAS, and proposed guidelines for MAS classification criteria may not be met.

Interleukin-6 Immunology in Macrophage Activation Syndrome Related to Neuroimmunological Diseases

Macrophage activation syndrome (MAS) involves an excessive amount of acute inflammatory responses to inflammatory cytokines, particularly interleukin-6 (IL-6). IL-6 is also strongly associated with the pathophysiology of certain neuroimmunological diseases. However, there have so far been few reports of MAS being accompanied by neuroimmunological diseases. We herein report two cases of MAS comorbid with myasthenia gravis or neuromyelitis optica spectrum disorders, IL-6 related neuroimmunological diseases. Standard immunosuppressive therapies could not stabilize the symptoms in our cases until antibodies against the IL-6 receptor were administered. This finding suggests that it is important to consider the underlying pathophysiology of MAS in relation to these neuroimmunological diseases when treating affected patients.

Hemophagocytic lymphohistiocytosis after solid organ transplantation: A challenge for clinicians

Hemophagocytic lymphohistiocytosis (HLH) is a rare inflammatory disorder with a high mortality rate and a wide range of symptoms. Solid organ transplantation, which provides patients with a unique immunosuppressive state, is a less common predisposing factor for HLH. HLH after solid organ transplantation (HLH-SOT) is very rare and fatal. It is hard to diagnose and treat and extremely understudied. The use of immunosuppressants makes the situation of HLH-SOT more complex. This review summarizes the existing literature on HLH after solid organ transplantation and describes its triggers and symptoms, focusing on its diagnosis and treatment. We performed a literature search of case reports, case series, letters to the editor, and clinical quizzes describing patients with HLH after solid organ transplantation (HLH-SOT). We provide recommendations on the diagnosis protocol and treatment strategy based on the existing evidence.

Cytokine Storm Syndrome Associated with Systemic Juvenile Idiopathic Arthritis

The cytokine storm syndrome (CSS) associated with systemic juvenile idiopathic arthritis (sJIA) has widely been referred to as macrophage activation syndrome (MAS). In this chapter, we use the term sJIA-associated CSS (sJIA-CSS) when referring to this syndrome and use the term MAS when referencing publications that specifically report on sJIA-associated MAS.

Risk of Macrophage Activation Syndrome in Patients with Adult-Onset Still's Disease Treated with IL-1 and IL-6 Inhibitors: A Meta-analysis and Single-Center Experience

INTRODUCTION

Patients with adult-onset Still's disease (AOSD) are at risk of developing macrophage activation syndrome (MAS), a life-threatening condition. Some cases of MAS have been reported following the use of biological agents, highlighting the need to identify contributing factors. This study aims to examine the characteristics of MAS in patients with AOSD treated with anakinra (ANA) or tocilizumab (TCZ).

METHODS

A systematic search was conducted across four online databases to identify studies reporting the incidence rates of MAS in patients with AOSD treated with ANA or TCZ. Meta-analysis was performed using a random-effects model and the generic inverse variance method to estimate the pooled incidence rates. The difference in incidence rates of MAS between TCZ and ANA was assessed. Additionally, we analyzed laboratory data and clinical features of AOSD cases at our institution, stratifying them into two groups: those who developed MAS after TCZ administration and those who did not.

RESULTS

Of the 455 screened articles, we included five ANA and six TCZ studies. The pooled incidence rates of MAS were 1.50% (95% confidence interval [CI], 0-3.36) for ANA (345 patients) and 14.01% (95% CI 4.51-23.51) for TCZ (94 patients). MAS incidence was significantly higher in the TCZ group (P = 0.01). Among the 17 patients from our institution, the six patients who developed MAS had significantly higher white blood cell and neutrophil counts, as well as elevated levels of lactate dehydrogenase, C-reactive protein, and ferritin before TCZ induction (P < 0.05).

CONCLUSIONS

In patients with AOSD, the manifestation of MAS is influenced by multiple causative factors. Consequently, the administration of TCZ should be approached with caution, particularly in patients exhibiting elevated inflammatory markers.

TRIAL REGISTRATION

This study was registered with the Clinical Trial Registry of the University Hospital Medical Information Network (Japan) as UMIN000049243.

IL-18 in Autoinflammatory Diseases: Focus on Adult Onset Still Disease and Macrophages Activation Syndrome

Interleukin-18 (IL-18) is a potent pro-inflammatory cytokine that is involved in various innate and adaptive immune processes related to infection, inflammation, and autoimmunity. Therefore, it is described as a key mediator of autoinflammatory diseases associated with the development of macrophage activation syndrome (MAS), including systemic juvenile idiopathic arthritis and adult-onset Still's disease. This review focuses on the role of IL-18 in inflammatory responses, placing emphasis on autoinflammatory diseases associated with chronic excess of serum IL-18, which correlate with clinical and biological signs of the disease. Therefore, it is useful for the diagnosis and monitoring of disease activity. Researchers are currently investigating IL-18's role as a therapeutic target for the treatment of inflammatory diseases. The inhibition of IL-18 signaling through recombinant human IL-18BP (IL-18 binding protein) seems to be an effective therapeutic strategy, though further studies are necessary to clarify its importance as a therapeutic target.

Biological therapies for hemophagocytic lymphohistiocytosis: current knowledge and future perspectives

INTRODUCTION

Hemophagocytic lymphohistiocytosis (HLH) is a hyperinflammatory syndrome with a dismal prognosis. The underlying causes of HLH are diverse. However, the overabundance of cytokines was shared by all forms of HLH. Cytokine-targeted biotherapies have been increasingly used in HLH treatment.

AREAS COVERED

In this review, we aim to provide an overview of biological treatment options for HLH.

EXPERT OPINION

Biological therapies offer alternative treatment options for patients with refractory/relapsed HLH or who are intolerant to conventional chemotherapies. As a complement to traditional treatment, biological agents improve response rates, maintain more protracted periods of remission, and reduce treatment related toxicity. A combination of biological agents may be a promising direction for HLH treatment. However, they may induce HLH to deteriorate and even trigger HLH.

Treatment for macrophage activation syndrome associated with systemic juvenile idiopathic arthritis in Japan

OBJECTIVES

To clarify how pediatric rheumatologists treat systemic juvenile idiopathic arthritis (s-JIA) associated macrophage activation syndrome (MAS) in the real world and to assess the efficacy and safety of dexamethasone palmitate (DEX-P) in the treatment of s-JIA-associated MAS.

METHODS

This multicenter, retrospective study was conducted at 13 pediatric rheumatology institutes in Japan. This study included 28 patients with s-JIA-associated MAS. Clinical findings, such as treatment details and adverse events, were evaluated.

RESULTS

Methylprednisolone (mPSL) pulse therapy was selected as the first-line treatment in more than half of the patients with MAS. Cyclosporine A (CsA) was used as first-line therapy in combination with corticosteroids in half of the patients with MAS. DEX-P and/or CsA were selected as the second-line therapy in 63% of patients with corticosteroid-resistant MAS. Plasma exchange was selected as the third-line therapy for DEX-P and CsA-resistant MAS. All patients improved and there were no characteristically severe adverse events associated with DEX-P.

CONCLUSIONS

The first-line treatment for MAS in Japan is mPSL pulse therapy and/or CyA. DEX-P could be an effective and safe therapeutic option for patients with corticosteroid-resistant MAS.

Therapeutic plasma exchange in refractory macrophage activation syndrome complicating systemic juvenile idiopathic arthritis: a case-based review

Juvenile idiopathic arthritis (JIA) is a heterogeneous group of arthritis of autoimmune aetiology. Systemic-onset juvenile idiopathic arthritis (soJIA) presents with fever, transient erythematous rash, hepatomegaly, splenomegaly, lymphadenopathy, and serositis. SoJIA presents multiple complications, and the most severe is the macrophage activation syndrome (MAS); the timely treatment of MAS must be established early and aggressively to avoid a fatal outcome. Therapeutic plasma exchange has anecdotally been used in refractory cases. A 66-month-old male with a 1-year illness characterized by evening-predominant, intermittent fever, adenomegalies, urticarial-like rash, arthralgia, and arthritis. Biochemical analysis revealed anaemia, leukocytosis, neutrophilia, hypertriglyceridemia, hyperferritinemia, and hypofibrinogenemia; bone marrow aspirate showed hemophagocytosis. He was diagnosed with SoJIA complicated with MAS. He received multiple treatments with IV human gammaglobulin, cyclosporine, dexamethasone, and tocilizumab without improvement. Plasma replacement treatment was performed. Afterwards, he presented significant improvement. After 3-year-follow-up, he remains in good general condition. We present a refractory case of soJIA complicated with MAS successfully treated with plasma exchange.

Hemophagocytic lymphohistiocytosis: a case series analysis in a pediatric hospital

INTRODUCTION

Hemophagocytic lymphohistiocytosis (HLH) is a rare clinical laboratory condition with high mortality rates, resulting from ineffective overactivation of the immune system. Data in the Brazilian literature is scarce, contributing to the challenge in standardizing conducts and performing an early diagnosis of HLH.

OBJECTIVE

To describe the clinical, laboratory, and evolutionary findings on HLH patients treated at a pediatric hospital.

METHODS

This is an observational, cross-sectional and retrospective study on children diagnosed with HLH, hospitalized between 2009 and 2019. The diagnostic criteria were those described in the Histiocyte Society protocol. The authors evaluated HLH patient laboratory tests, myelograms and bone marrow biopsies, clinical characteristics and therapy.

RESULTS

Twenty-three patients were included, 52.2% of whom were males. The age at diagnosis ranged from one to one hundred and eighty months. Four cases were classified as Primary HLH and nineteen, as Secondary HLH. The main triggers were infections and rheumatological diseases. All children had bicytopenia, and 95.4% had hyperferritinemia. Nineteen patients had liver dysfunction, sixteen had neurological disorders and fourteen had kidney injury. Pulmonary involvement was seen in 61.9%, acting as a worse prognosis for death (p = 0.01). Nine patients underwent the immuno-chemotherapy protocol proposed in the HLH 2004. The time to confirm the diagnosis varied from five to eighty days. The lethality found was 56.3%.

CONCLUSIONS

The present study is the most extensive retrospective exclusively pediatric study published in Brazil to date. Despite the limitations, it was possible to demonstrate the importance of discussing HLH as a pediatric emergency.

Efficacy and safety of canakinumab as a second line biologic after tocilizumab treatment failure in children with systemic juvenile idiopathic arthritis: A single-centre cohort study using routinely collected health data

Background

A significant number of systemic juvenile idiopathic arthritis (sJIA) patients discontinue biologic disease-modifying antirheumatic drugs (bDMARDs) due to lack of efficacy or safety concerns. Studies of biologic therapy switch regimens in sJIA are required.

Methods

Patients with sJIA who switched from tocilizumab (due to lack of efficacy or safety) to canakinumab (4 mg/kg every 4 weeks) and were hospitalized at the rheumatology department from August 2012 to July 2020 were included. Primary efficacy outcomes were 30% or greater improvement based on the paediatric criteria of the American College of Rheumatology (ACR30), achievement of inactive disease (JADAS-71 = 0) and clinical remission (ACR sJIA clinical inactive disease criteria). Follow-up from time first canakinumab dose administered was 12 months or the closest time point (not less than 6 and not more than 18 months). Data were extracted from electronic outpatient medical records.

Results

During the study period, 46 patients with sJIA switched from tocilizumab to canakinumab. Median age at baseline was 8.2 [interquartile range (IQR) 4.0-12.9] years, with the median sJIA duration being 1.8 (IQR 0.8-5.8) years; 37 (80%) patients received at least one conventional DMARD (cDMARD; oral corticosteroids, methotrexate and/or cyclosporine A). Study outcomes were followed up in 45 patients (one patient did not attend the follow-up for an unknown reason); median follow-up was 359 (IQR 282-404) days. During the follow-up, 1 patient discontinued canakinumab due to tuberculosis detection and the dose was reduced or the injection interval increased in 4 (9%) patients. In total, 27 (60%) patients continued to receive at least one cDMARD. Improvement according to the ACR30 criteria was achieved in 43 patients [96%; 95% confidence interval (CI) 85-99], inactive disease in 42 (93%; 95%CI 82-98), and remission in 37 (82%; 95% CI 69-91); after adjustment for actual time-at-risk, the rates were 83, 85 and 73 events per 100 person-years, respectively. During follow-up, 23 AEs (most frequently infections) were reported in 19/45 (42%) patients; 5/45 (11%) patients developed macrophage activation syndrome, with a favorable outcome in all cases.

Conclusions

One-year canakinumab therapy was found to be potentially effective as second-line biologic therapy after discontinuation of tocilizumab in patients with sJIA.

Adult-Onset Still's Disease-A Complex Disease, a Challenging Treatment

Adult-onset Still's disease (AOSD) is a systemic inflammatory disorder with an unknown cause characterized by high-spiking fever, lymphadenopathy, hepatosplenomegaly, hyperferritinemia, and leukocytosis. The clinical course can be divided into three significant patterns, each with a different prognosis: Self-limited or monophasic, intermittent or polycyclic systemic, and chronic articular. Two criteria sets have been validated. The Yamaguchi criteria are the most generally used, although the Fautrel criteria offer the benefit of adding ferritin and glycosylated ferritin values. AOSD's pathogenesis is not yet completely understood. Chemokines and pro-inflammatory cytokines, including interferon (IFN)-γ, tumor necrosis factor α (TNFα), interleukin (IL)-1, IL-6, IL-8, and IL-18, play a crucial role in the progression of illness, resulting in the development of innovative targeted therapeutics. There are no treatment guidelines for AOSD due to its rarity, absence of controlled research, and lack of a standard definition for remission and therapy objectives. Non-steroidal anti-inflammatory drugs (NSAIDs), corticosteroids (CS), and conventional synthetic disease-modifying antirheumatic drugs (csDMARDs) are used in AOSD treatment. Biological therapy, including IL-1, IL-6, IL-18, and IL-17 inhibitors, as well as TNFα or Janus-kinases (JAKs) inhibitors, is administered to patients who do not react to CS and csDMARDs or achieve an inadequate response.

Renal involvement as a unique manifestation of hemophagocytic syndrome

Renal-limited hemophagocytic syndrome (HPS) is a rare clinical setting characterized by abnormal activation of the immune system. Fever associated with pancytopenia, hepatosplenomegaly with liver dysfunction, and hypofibrinogenemia are usually observed in HPS. From a histological level, the presence of non-malignant macrophages infiltrating bone marrow and organs represents the hallmark of this condition. Non-malignant macrophages are associated with phagocytizing activities involving other blood cells. While primary HPS is usually associated with inherited dysregulation of the immune system, secondary HPS usually occurs in the context of infection or is linked to a neoplastic process. Clinical presentation varies and can potentially lead to life-threatening settings. While renal involvement has frequently been reported, however, detailed descriptions of the kidney manifestations of HPS are lacking. More critically, the diagnosis of HPS is rarely supported by renal biopsy specimens. We report four rare cases of biopsy-proven renal-limited HPS in patients presenting with acute kidney injury (AKI). The available evidence on this topic is critically discussed in light of the possible emergence of an autonomous entity characterized by an isolated kidney involvement.

Pathogenic roles and diagnostic utility of interleukin-18 in autoinflammatory diseases

Interleukin (IL)-18 is a pleiotropic, pro-inflammatory cytokine involved in the regulation of innate and adaptive immune responses. IL-18 has attracted increasing attention as a key mediator in autoinflammatory diseases associated with the development of macrophage activation syndrome (MAS) including systemic juvenile idiopathic arthritis and adult-onset Still’s disease. In these diseases, dysregulation of inflammasome activity and overproduction of IL-18 might be associated with the development of MAS by inducing natural killer cell dysfunction. Serum IL-18 levels are high in patients with these diseases and therefore are useful for the diagnosis and monitoring of disease activity. In contrast, a recent study revealed the overproduction of IL-18 was present in cases of autoinflammation without susceptibility to MAS such as pyogenic sterile arthritis, pyoderma gangrenosum, and acne (PAPA) syndrome. The pathogenic and causative roles of IL-18 remain unclear in these autoinflammatory diseases. Further investigations are necessary to clarify the role of IL-18 and its importance as a therapeutic target in the pathogenesis of autoinflammatory diseases.

Consensus statement on blocking interleukin-6 receptor and interleukin-6 in inflammatory conditions: an update

BACKGROUND

Targeting interleukin (IL)-6 has become a major therapeutic strategy in the treatment of immune-mediated inflammatory disease. Interference with the IL-6 pathway can be directed at the specific receptor using anti-IL-6Rα antibodies or by directly inhibiting the IL-6 cytokine. This paper is an update of a previous consensus document, based on most recent evidence and expert opinion, that aims to inform on the medical use of interfering with the IL-6 pathway.

METHODS

A systematic literature research was performed that focused on IL-6-pathway inhibitors in inflammatory diseases. Evidence was put in context by a large group of international experts and patients in a subsequent consensus process. All were involved in formulating the consensus statements, and in the preparation of this document.

RESULTS

The consensus process covered relevant aspects of dosing and populations for different indications of IL-6 pathway inhibitors that are approved across the world, including rheumatoid arthritis, polyarticular-course and systemic juvenile idiopathic arthritis, giant cell arteritis, Takayasu arteritis, adult-onset Still's disease, Castleman's disease, chimeric antigen receptor-T-cell-induced cytokine release syndrome, neuromyelitis optica spectrum disorder and severe COVID-19. Also addressed were other clinical aspects of the use of IL-6 pathway inhibitors, including pretreatment screening, safety, contraindications and monitoring.

CONCLUSIONS

The document provides a comprehensive consensus on the use of IL-6 inhibition to treat inflammatory disorders to inform healthcare professionals (including researchers), patients, administrators and payers.

Cytokine storm and targeted therapy in hemophagocytic lymphohistiocytosis

Hemophagocytic lymphohistiocytosis (HLH) is a life-threatening systemic hyperinflammatory syndrome. The central pathogenesis is an explosive cytokine storm characterized by a significant increase in proinflammatory cytokines, including IL-1β, IL-6, IL-18, IFN-γ, and TNF-α. Meanwhile, negative regulatory factors, such as IL-10 and TGF-β, are also related to the production of HLH. Exploring the specific mechanism of cytokine storms could provide ideas regarding targeted therapy, which could be helpful for early treatment to reduce the mortality of HLH. Although some research has focused on the advantages of targeted therapies, there is still a lack of a comprehensive discourse. This article attempts to summarize the mechanisms of action of various cytokines and provide a therapeutic overview of the current targeted therapies for HLH.

Baseline clinical features predicting macrophage activation syndrome in patients with systemic adult-onset Still's disease receiving interleukin-6 inhibitor treatment

AIM

Macrophage activation syndrome (MAS), a severe complication of systemic adult-onset Still's disease (AOSD), has been reported to occur during interleukin-6 (IL-6) inhibitor treatment. However, predictors for MAS development are unknown. Therefore, this study investigated predictive features for MAS development after starting IL-6 inhibitor treatment in systemic AOSD patients.

METHOD

In a single-center retrospective study involving systemic AOSD patients who were refractory to high-dose glucocorticoids with immunosuppressants and started IL-6 inhibitor treatment between April 2008 and March 2020, we compared the baseline clinical features between patients who developed AOSD flare with MAS features (MAS group) and those who did not (non-MAS group) during IL-6 inhibitor treatment.

RESULTS

Only tocilizumab was used as an IL-6 inhibitor. Six of 14 refractory systemic AOSD patients developed AOSD flares with MAS features during tocilizumab treatment, including 4 who developed them shortly after initiation. The MAS group had significantly lower neutrophil counts, fibrinogen, and higher IL-18/C-reactive protein (CRP) ratio at starting tocilizumab (baseline) than the non-MAS group. Before starting tocilizumab, neutrophil counts were trending downward and upward in the MAS and non-MAS groups, respectively, with significant differences in changes. Receiver operating characteristic analysis showed that baseline neutrophil counts and fibrinogen and their changes before tocilizumab treatment and baseline IL-18/CRP ratio had significant discriminatory abilities for subsequent MAS development.

CONCLUSION

We identified baseline laboratory features associated with MAS development after initiating an IL-6 inhibitor in refractory systemic AOSD patients. These features may reflect the suppression of IL-6 signaling, and further suppression of IL-6 signaling might trigger early-onset MAS.

COVID‑19: Main findings after a year and half of unease and the proper scientific progress (Review)

Since the emergence of the disease in late December 2019, numerous studies have been published to date regarding clinical, laboratory and treatment aspects associated with COVID-19. The present study attempts to compare and unify the clinical, para-clinical and therapeutic aspects that have come to light regarding coronavirus disease-19 (COVID 19), mainly in adults. Between April 2020 and September 2021, a comprehensive systematic literature review was performed, which we added to from our own medical experiences. The search was performed on the PubMed, Scopus and Google Scholar databases, comprising studies with analyzable data that were identified alongside studies and documents containing general scientific data. All published studies were written in English, and were from different countries. A 95% confidence interval (CI95) was also calculated for almost each study using the Wilson formula. When compared with preliminary reports between December 2019 and January 2020, the most frequent symptoms were still identified as being fever (68.6%; CI95: 67.5-69.7) and cough (72.7%; CI95: 71.7-73.8). Nevertheless, asymptomatic cases also increased (by 21.4%; CI95: 16.6-27.1). Severe and critical cases accounted for 10.4% (CI95: 9.6-11.1) of all cases. The mean fatality rate was found to be 4% (CI95: 3.6-4.5). The primary co-morbidity found was hypertension (28.9%; CI95: 27-30.8), followed by other underlying cardiovascular diseases (15.4%; CI95: 13.9-16.9) and diabetes (14.5%; CI95: 13.1-16.1). The majority of studies showed lower white blood cell numbers with neutropenia and lymphopenia, and lower platelet levels. The levels of the biomarkers C-reaction protein and erythrocyte sedimentation rate were positive in all studied cases alongside other lab tests, such as examining the D-dimer levels and those of other hepatic, cardiac and renal injury markers. The procalcitonin level was also found to be elevated in many cases, resulting in high usage of antibiotics (83.7%; CI95: 81.2-85.9). Approximately 31.6% (CI95: 29.1-34.1) of the patients required non-invasive ventilation, whereas 9.9% (CI95: 8.1-12.1) of the patients were intubated or placed on extracorporeal membrane oxygenation. The most used antivirals were ribavirin (67.3%; CI95: 63.4-70.9), oseltamivir (52.5%; CI95: 49.4-55.5) and Arbidol™ (34.5%; CI95: 32-37.1). General admittance to the intensive care unit was ~7.2% (CI95: 6.5-7.9) of patients.

Anakinra in Patients With Systemic Juvenile Idiopathic Arthritis: Long-term Safety From the Pharmachild Registry

OBJECTIVE

To evaluate the long-term safety profile of anakinra in patients with systemic juvenile idiopathic arthritis (sJIA).

METHODS

Data from patients with sJIA enrolled in the Pharmachild registry (ClinicalTrials.gov: NCT03932344) prior to September 30, 2018, and treated with anakinra were analyzed. The study endpoints were the occurrence of non-serious adverse events (SAEs) of at least moderate severity and SAEs, including macrophage activation syndrome (MAS), and the duration of anakinra treatment with reasons for discontinuation. All endpoints were analyzed overall by 6-month time windows, and in different treatment sets represented by those patients treated continuously with anakinra for at least 12, 18, and 24 months (set-12, -18, and -24, respectively).

RESULTS

Three hundred six patients were enrolled. Of these patients, 46%, 34%, and 28% had been treated for at least 12, 18, and 24 months, respectively. Two hundred and one AEs, mostly represented by infections, were reported for 509.3 patient-years (PY) with an overall incidence rate (IR) of 39.5 per 100 PY. Among 56 SAEs (IR 11.0/100 PY), 23.2% were infections and 19.6% MAS episodes. The IR of AEs was higher during the first 6 months of anakinra treatment, followed by decreasing IRs in the long-term treatment sets. Treatment discontinuation occurred in 76% of patients, most frequently in the first 6 months, because of inefficacy (43%), remission (31%), or AEs/intolerance (15%). No deaths or malignancies occurred during anakinra treatment.

CONCLUSION

The results of the present study confirm the long-term safety profile of anakinra in patients with sJIA and demonstrate an overall decreasing incidence of AEs over time. [ClinicalTrials.gov: NCT01399281 and NCT03932344].

A Case of Macrophage Activation Syndrome During the Treatment of Adult-onset Still's Disease With Tocilizumab

Macrophage activation syndrome (MAS) is a fatal complication of adult-onset Still's disease (AOSD). Although anti-cytokine agents have been recommended for refractory AOSD or complicated with MAS, MAS cases have been rarely reported during anti-cytokine treatment. Herein, we describe the first AOSD case complicated with MAS during the treatment with tocilizumab in Korea. Two years after tocilizumab maintenance therapy, high fever and hypertransaminasemia recurred. MAS was diagnosed based on hyperferritinemia, elevated soluble IL-2 receptor levels, and the presence of hemophagocytic histiocytes in the bone marrow. However, she had normal white blood cell counts and acute phase reactant levels. High-dose glucocorticoid and anakinra therapies were not effective, but her disease improved with etoposide. This case shows that tocilizumab may not prevent MAS development and can modify clinical features making it challenging to diagnose. Cytotoxic therapy such as etoposide may be required in MAS cases that develop during anti-cytokine therapy.

Macrophage activation syndrome in patients with adult-onset Still's disease under tocilizumab treatment: A single-center observational study

OBJECTIVES

Macrophage activation syndrome (MAS) developed under tocilizumab treatment poses a diagnostic challenge. This study aims to demonstrate the frequency and the clinical features of MAS developed in patients with adult-onset Still's disease (AOSD) receiving tocilizumab.

METHODS

The consecutive AOSD patients treated with tocilizumab in our institution from April 2008 to March 2020 were studied. The frequency of clinically diagnosed MAS during tocilizumab treatment, their conformity to the several criteria relevant for MAS, and laboratory characteristics compared to AOSD flare were investigated.

RESULTS

Of the 20 AOSD patients treated with tocilizumab, six developed clinically diagnosed MAS, four immediately after starting tocilizumab and two after long-term treatment. Some of them had already met the MAS criteria before starting tocilizumab. At MAS diagnosis, although some did not meet the MAS criteria due to lack of fever and/or the lower ferritin levels, all consistently showed sharp increases in ferritin along with marked abnormal changes in two or more different markers of organ damage, unlike the AOSD flares.

CONCLUSION

MAS is not a rare complication in AOSD patients receiving tocilizumab. The clinical similarities between systemic AOSD and MAS, and substantial alterations in MAS features by inhibition of interleukin-6 signaling may limit the utility of the existing diagnostic/classification criteria in diagnosing MAS under tocilizumab treatment. The emergence of abnormalities in MAS-related organ damage markers with a rapid elevation of ferritin should be considered as MAS development in AOSD patients receiving tocilizumab even if the patients are afebrile or have relatively low ferritin levels.

Interluekin-6 inhibitors for the treatment of adult-onset Still's disease

Adult-onset Still's disease is a systemic inflammatory disease characterized by high spiking fever, arthritis, evanescent skin rash, leukocytosis, and hyperferritinemia. The pathogenesis of adult-onset Still's disease has not been fully understood yet; however, multiple proinflammatory cytokines, such as IL-1β and IL-6, play important roles in the development of adult-onset Still's disease. IL-6 is a multifunctional cytokine that accelerates the differentiation of macrophages and cytotoxic T-cells and chemotaxis of neutrophils and macrophages. Serum concentrations of IL-6 well correlate with disease activity of adult-onset Still's disease, and blockade of IL-6 has been proven to be effective in active adult-onset Still's disease. This review will focus on the recent understanding of the role of proinflammatory cytokines of adult-onset Still's disease and the efficacy of IL-6 inhibitors for the treatment of adult-onset Still's disease.

Pathogenesis and Treatment of Refractory Disease Courses in Systemic Juvenile Idiopathic Arthritis: Refractory Arthritis, Recurrent Macrophage Activation Syndrome and Chronic Lung Disease

Systemic juvenile idiopathic arthritis is a distinct and heterogeneous disease presently classified under the umbrella of juvenile idiopathic arthritis, with some patients following a monophasic remitting course, whereas others have persistent disease with chronic organ- and life-threatening complications. Although biologic therapies have revolutionized treatment, recent follow-up studies report significant numbers of children with persistently active disease on long term follow-up. This review focuses on refractory disease courses, specifically refractory arthritis, systemic juvenile idiopathic arthritis with recurrent, or longstanding signs of macrophage activation syndrome, and systemic juvenile idiopathic arthritis associated with suspected, probable, or definite lung disease.

Treatment of Connective Tissue Disease-Related Intractable Disease with Biological Therapeutics

The treatment of connective tissue disease (CTD) and CTD-related intractable diseases (CTD-IDs) currently depends on the use of steroid therapy. Approximately 20 years have passed since the approval of infliximab for rheumatoid arthritis in 2003. Since then, several biological therapeutics have been marketed and adapted for many CTDs and CTD-IDs other than rheumatoid arthritis. Although conventional treatment for patients with these diseases is rarely used because of their poor prognosis, these cases may benefit from biological therapeutics. However, choosing biological therapeutics is difficult because they have different target molecules compared with conventional therapeutics. In this review, we address the current situation of biological therapeutics for CTD-IDs including Behcet's disease, psoriatic arthritis, ankylosing spondylitis, anti-neutrophil cytoplasmic antibody-related arthritis, and adult Still's disease, as well as the choice of biological therapeutics in clinical practice.

Interleukin-6 inhibition: a therapeutic strategy for the management of adult-onset Still's disease

Introduction:Patients with adult-onset Still's disease have markedly elevated serum levels of proinflammatory cytokines, such as IL-1β, IL-6, and IL-18, suggesting the potential of these molecules as therapeutic targets. IL-6 accelerates macrophage and cytotoxic T-cell differentiation and neutrophil and macrophage chemotaxis and is one of the most important cytokines in the pathogenesis of adult-onset Still's disease.Areas covered:The review summarizes the importance of IL-6 in the pathogenesis of adult-onset Still's disease and clinical aspects of IL-6 inhibition from retrospective and prospective studies.Expert opinion:Adult-onset Still's disease is a systemic inflammatory disease of unknown etiology and characterized by elevated various proinflammatory cytokines. In particular, serum concentrations of IL-6 is significantly high in patients with active adult-onset Still's disease, and many case reports, cohort studies and one randomized, placebo-controlled trail have shown the efficacy of IL-6 blockade in patients with adult-onset Still's disease who were refractory to glucocorticoids and other immunosuppressive treatments. IL-6 inhibition is effective for both systemic and joint manifestations with arthritis improving slowly. There is still a concern over the triggering of macrophage activation syndrome; however, the IL-6 inhibition strategy has introduced better management of adult-onset Still's disease.

Macrophage activation syndrome in systemic juvenile idiopathic arthritis

Macrophage activation syndrome (MAS) is a severe, potentially life-threatening complication of systemic juvenile idiopathic arthritis (s-JIA). An immunological feature is the excessive activation and proliferation of T lymphocytes and macrophages. Massive hypercytokinemia is strongly associated with its pathogenesis, particularly the overproduction of interleukin (IL)-1, IL-6 and IL-18; interferon (IFN)-γ; and tumor necrosis factor (TNF)-α. Furthermore, heterozygous mutations in causative genes for primary hemophagocytic lymphohistiocytosis and in vivo exposure to highly elevated levels of IL-6 and IL-18 might induce natural killer cell dysfunction and decrease their numbers, respectively. A proper diagnosis is important to begin appropriate therapeutic interventions and change an unfavorable prognosis. The 2016 ACR/EULAR classification criteria for MAS have a high diagnostic performance; however, the diagnostic sensitivity for onset is relatively low. Therefore, careful monitoring of laboratory values during the course of MAS is necessary to diagnose it early in s-JIA. Further studies on the diagnosis and monitoring of disease activity using serum cytokine profile and a targeted cytokine strategy are required.

The Pathogenic Role of Interferons in the Hyperinflammatory Response on Adult-Onset Still's Disease and Macrophage Activation Syndrome: Paving the Way towards New Therapeutic Targets

Adult-onset Still's disease (AOSD) is a systemic inflammatory disorder of unknown aetiology affecting young adults, which is burdened by life-threatening complications, mostly macrophage activation syndrome (MAS). Interferons (IFNs) are signalling molecules that mediate a variety of biological functions from defence against viral infections, to antitumor and immunomodulatory effects. These molecules have been classified into three major types: IFN I, IFN II, IFN III, presenting specific characteristics and functions. In this work, we reviewed the role of IFNs on AOSD and MAS, focusing on their pathogenic role in promoting the hyperinflammatory response and as new possible therapeutic targets. In fact, both preclinical and clinical observations suggested that these molecules could promote the hyperinflammatory response in MAS during AOSD. Furthermore, the positive results of inhibiting IFN-γ in primary hemophagocytic lymphohistiocytosis may provide a solid rationale to arrange further clinical studies, paving the way for reducing the high mortality rate in MAS during AOSD.

Immune cartography of macrophage activation syndrome in the COVID-19 era

A hyperinflammatory 'cytokine storm' state termed macrophage activation syndrome (MAS), culminating from a complex interplay of genetics, immunodeficiency, infectious triggers and dominant innate immune effector responses, can develop across disparate entities including systemic juvenile idiopathic arthritis (sJIA) and its counterpart adult-onset Still disease (AOSD), connective tissue diseases, sepsis, infection, cancers and cancer immunotherapy. Classifying MAS using the immunological disease continuum model, with strict boundaries that define the limits of innate and adaptive immunity, at one boundary is MAS with loss of immune function, as occurs in the 'perforinopathies' and some cases of sJIA-AOSD. Conversely, at the other boundary, immune hypersensitivity with gain of immune function in MHC class II-associated sJIA-AOSD and with chimeric antigen receptor (CAR) T cell therapy also triggers MAS. This provides a benchmark for evaluating severe inflammation in some patients with COVID-19 pneumonia, which cripples primary type I interferon immunity and usually culminates in a lung-centric 'second wave' cytokine-driven alveolitis with associated immunothrombosis; this phenomenon is generally distinct from MAS but can share features with the proposed 'loss of immune function' MAS variant. This loss and gain of function MAS model offers immune cartography for a novel mechanistic classification of MAS with therapeutic implications.

Novel Coronavirus Disease 2019 (COVID-19) and Cytokine Storms for More Effective Treatments from an Inflammatory Pathophysiology

The Novel Coronavirus Disease 2019 (COVID-19) has swept the world and caused a global pandemic. SARS-CoV-2 seems to have originated from bats as their reservoir hosts over time. Similar to SARS-CoV, this new virus also exerts its action on the human angiotensin-converting enzyme 2. This action causes infections in cells and establishes an infectious disease, COVID-19. Against this viral invasion, the human body starts to activate the innate immune system in producing and releasing proinflammatory cytokines such as IL-6, IL-1β, IL-8, TNF-α, and other chemokines, such as G-CSF, IP10 and MCPl, which all develop and increase the inflammatory response. In cases of COVID-19, excessive inflammatory responses occur, and exaggerated proinflammatory cytokines and chemokines are detected in the serum, resulting in cytokine release syndrome or cytokine storm. This causes coagulation abnormalities, excessive oxidation developments, mitochondrial permeability transition, vital organ damage, immune system failure and eventually progresses to disseminated intravascular coagulation and multiple organ failure. Additionally, the excessive inflammatory responses also cause mitochondrial dysfunction due to progressive and persistent stress. This damages cells and mitochondria, leaving products containing mitochondrial DNA and cell debris involved in the excessive chronic inflammation as damage-associated molecular patterns. Thus, the respiratory infection progressively leads to disseminated intravascular coagulation from acute respiratory distress syndrome, including vascular endothelial cell damage and coagulation-fibrinolysis system disorders. This condition causes central nervous system disorders, renal failure, liver failure and, finally, multiple organ failure. Regarding treatment for COVID-19, the following are progressive and multiple steps for mitigating the excessive inflammatory response and subsequent cytokine storm in patients. First, administering of favipiravir to suppress SARS-CoV-2 and nafamostat to inhibit ACE2 function should be considered. Second, anti-rheumatic drugs (monoclonal antibodies), which act on the leading cytokines (IL-1β, IL-6) and/or cytokine receptors such as tocilizumab, should be administered as well. Finally, melatonin may also have supportive effects for cytokine release syndrome, resulting in mitochondrial function improvement. This paper will further explore these subjects with reports mostly from China and Europe.

Association of novel rare coding variants with juvenile idiopathic arthritis

OBJECTIVE

Juvenile idiopathic arthritis (JIA) is the most common type of arthritis among children, but a few studies have investigated the contribution of rare variants to JIA. In this study, we aimed to identify rare coding variants associated with JIA for the genome-wide landscape.

METHODS

We established a rare variant calling and filtering pipeline and performed rare coding variant and gene-based association analyses on three RNA-seq datasets composed of 228 JIA patients in the Gene Expression Omnibus against different sets of controls, and further conducted replication in our whole-exome sequencing (WES) data of 56 JIA patients. Then we conducted differential gene expression analysis and assessed the impact of recurrent functional coding variants on gene expression and signalling pathway.

RESULTS

By the RNA-seq data, we identified variants in two genes reported in literature as JIA causal variants, as well as additional 63 recurrent rare coding variants seen only in JIA patients. Among the 44 recurrent rare variants found in polyarticular patients, 10 were replicated by our WES of patients with the same JIA subtype. Several genes with recurrent functional rare coding variants have also common variants associated with autoimmune diseases. We observed immune pathways enriched for the genes with rare coding variants and differentially expressed genes.

CONCLUSION

This study elucidated a novel landscape of recurrent rare coding variants in JIA patients and uncovered significant associations with JIA at the gene pathway level. The convergence of common variants and rare variants for autoimmune diseases is also highlighted in this study.

Monocyte and bone marrow macrophage transcriptional phenotypes in systemic juvenile idiopathic arthritis reveal TRIM8 as a mediator of IFN-γ hyper-responsiveness and risk for macrophage activation syndrome

OBJECTIVES

Systemic juvenile idiopathic arthritis (SJIA) confers high risk for macrophage activation syndrome (MAS), a life-threatening cytokine storm driven by interferon (IFN)-γ. SJIA monocytes display IFN-γ hyper-responsiveness, but the molecular basis of this remains unclear. The objective of this study is to identify circulating monocyte and bone marrow macrophage (BMM) polarisation phenotypes in SJIA including molecular features contributing to IFN response.

METHODS

Bulk RNA-seq was performed on peripheral blood monocytes (n=26 SJIA patients) and single cell (sc) RNA-seq was performed on BMM (n=1). Cultured macrophages were used to define consequences of tripartite motif containing 8 (TRIM8) knockdown on IFN-γ signalling.

RESULTS

Bulk RNA-seq of SJIA monocytes revealed marked transcriptional changes in patients with elevated ferritin levels. We identified substantial overlap with multiple polarisation states but little evidence of IFN-induced signature. Interestingly, among the most highly upregulated genes was TRIM8, a positive regulator of IFN-γ signalling. In contrast to PBMC from SJIA patients without MAS, scRNA-seq of BMM from a patient with SJIA and MAS identified distinct subpopulations of BMM with altered transcriptomes, including upregulated IFN-γ response pathways. These BMM also showed significantly increased expression of TRIM8. In vitro knockdown of TRIM8 in macrophages significantly reduced IFN-γ responsiveness.

CONCLUSIONS

Macrophages with an 'IFN-γ response' phenotype and TRIM8 overexpression were expanded in the bone marrow from an MAS patient. TRIM8 is also upregulated in SJIA monocytes, and augments macrophage IFN-γ response in vitro, providing both a candidate molecular mechanism and potential therapeutic target for monocyte hyper-responsiveness to IFNγ in cytokine storms including MAS.

Comparison of serum biomarkers for the diagnosis of macrophage activation syndrome complicating systemic juvenile idiopathic arthritis during tocilizumab therapy

BACKGROUND

To compare the accuracy of serum biomarkers for the diagnosis of macrophage activation syndrome (MAS) complicating systemic juvenile idiopathic arthritis (s-JIA) during tocilizumab therapy.

METHODS

Serum cytokine levels of neopterin, IL-18, C-X-C motif chemokine ligand 9, soluble tumor necrosis factor receptor (sTNFR)-I, and sTNFR-II were determined by enzyme-linked immunosorbent assay in 36 patients with MAS complicating s-JIA including 12 patients receiving tocilizumab. Furthermore, the serum sTNFR-II/I ratio was compared with the clinical features of MAS.

RESULTS

The levels of all serum cytokines at MAS diagnosis were significantly lower in the tocilizumab-treated group than in the tocilizumab-untreated group. In contrast, the serum sTNFR-II/I ratio at MAS diagnosis was comparable between the tocilizumab-treated and the tocilizumab-untreated groups. The receiver operating characteristic curve analysis revealed that the area under the curve and cut-off values of sTNFR-II/I ratio were 0.9722 and 4.71, respectively. The serum sTNFR-II/I ratio, which was significantly elevated in patients with MAS complicating s-JIA, was correlated positively with disease activity.

CONCLUSIONS

These findings suggest that the serum sTNFR-II/I ratio might be a useful indicator to evaluate disease activity in MAS complicating s-JIA and a useful diagnostic marker for the transition from active-phase s-JIA to MAS even in tocilizumab-treated patients.

IMPACT

This is the first study to analyze the role of tocilizumab in modifying the serum levels of biomarkers used for the diagnosis of MAS complicating s-JIA. We found the biomarker for the diagnosis of MAS complicating s-JIA during tocilizumab therapy. We hope our results might be useful for the development of a new criteria for the diagnosis of MAS complicating s-JIA in patients treated with tocilizumab in future.

Reintroduction of tocilizumab elicited macrophage activation syndrome in a patient with adult-onset Still's disease with a previous successful tocilizumab treatment

Macrophage activation syndrome (MAS) is a form of secondary hemophagocytic lymphohistiocytosis and is a rapidly progressive, life-threatening complication of adult-onset Still's disease (AOSD). An anti-IL-6 receptor monoclonal antibody, tocilizumab, has shown to be effective in the treatment of AOSD but may precipitate MAS in patients with AOSD. The precise mechanism of MAS developed during anti-cytokine biologic agents remains unknown, but selective inhibition of a subset of pathways could impact other immune signalling pathways and trigger MAS. We herein describe a case of AOSD with the opposite outcomes of tocilizumab therapy, remission and development of MAS, after tocilizumab treatment at the initial flare and the relapse. From the comparison of clinical characteristics and concomitant treatment around the time of starting tocilizumab in both flares, the type and intensity of concomitant immunosuppressive therapy might strongly affect MAS development during tocilizumab therapy.

Proceedings from the 2nd Next Gen Therapies for Systemic Juvenile Idiopathic Arthritis and Macrophage Activation Syndrome symposium held on October 3-4, 2019

For reasons poorly understood, and despite the availability of biological medications blocking IL-1 and IL-6 that have markedly improved overall disease control, children with Systemic Juvenile Idiopathic Arthritis (SJIA) are now increasingly diagnosed with life-threatening chronic complications, including hepatitis and lung disease (SJIA-LD). On October 3-4, 2019, a two-day meeting, NextGen Therapies for Systemic Juvenile Idiopathic Arthritis (SJIA) & macrophage activation syndrome (MAS) organized by the Systemic JIA Foundation ( www.systemicjia.org/ ) in Washington, DC brought together scientists, clinicians, parents and FDA representatives with the objectives (1) to integrate clinical and research findings in MAS and SJIA-LD, and (2) to develop a shared understanding of this seemingly new pulmonary complication of SJIA. The current manuscript summarizes discussions and conclusions of the meeting.

Hemophagocytic lymphohistiocytosis: a review inspired by the COVID-19 pandemic

Hemophagocytic syndrome (HPS) or hemophagocytic lymphohistiocytosis (HLH) is an acute and rapidly progressive systemic inflammatory disorder characterized by cytopenia, excessive cytokine production, and hyperferritinemia. Common clinical manifestations of HLH are acute unremitting fever, lymphadenopathy, hepatosplenomegaly, and multiorgan failure. Due to a massive cytokine release, this clinical condition is considered as a cytokine storm syndrome. HPS has primary and acquired (secondary, reactive) forms. Its primary form is mostly seen in childhood and caused by various mutations with genetic inheritance and, therefore, is called familial HLH. Secondary HLH may be caused in the presence of an underlying disorder, that is, secondary to a malignant, infectious, or autoimmune/autoinflammatory stimulus. This paper aims to review the pathogenesis and the clinical picture of HLH, and its severe complication, the cytokine storm, with a special emphasis on the developed classification criteria sets for rheumatologists, since COVID-19 infection has clinical symptoms resembling those of the common rheumatologic conditions and possibly triggers HLH. MED-LINE/Pubmed was searched from inception to April 2020, and the following terms were used for data searching: “hemophagocytic syndrome” OR “macrophage activation syndrome” OR “hemophagocytic lymphohistiocytosis”, OR “cytokine storm”. Finally, AND “COVID-19” was included in this algorithm. The selection is restricted to the past 5 years and limited numbers of earlier key references were manually selected. Only full-text manuscripts, published in an English language peer-reviewed journal were included. Manuscript selection procedure and numbers are given in Fig. 2. Briefly, the database search with the following terms of “Hemophagocytic syndrome” OR “Macrophage activation syndrome” OR “Hemophagocytic lymphohistiocytosis” OR “Cytokine storm” yielded 6744 results from inception to April 2020. The selection is restricted to the past 5 years and only limited numbers of earlier key references were selected, and this algorithm resulted in 3080 manuscripts. The addition of (AND “COVID-19”) resulted in 115 publications of which 47 studies, together with four sections of an online book were used in the final review. No statistical method was used. HLH is triggered by genetic conditions, infections, malignancies, autoimmune-autoinflammatory diseases, and some drugs. In COVID-19 patients, secondary HLH and cytokine storm may be responsible for unexplained progressive fever, cytopenia, ARDS, neurological and renal impairment. Differentiation between the primary and secondary forms of HLH is utterly important, since primary form of HLH requires complicated treatments such as hematopoietic stem cell transplantation. Further studies addressing the performance of HScore and other recommendations in the classification of these patients is necessary.

The Role of Cytokines including Interleukin-6 in COVID-19 induced Pneumonia and Macrophage Activation Syndrome-Like Disease

Severe COVID-19 associated pneumonia patients may exhibit features of systemic hyper-inflammation designated under the umbrella term of macrophage activation syndrome (MAS) or cytokine storm, also known as secondary haemophagocytic lymphohistocytosis (sHLH). This is distinct from HLH associated with immunodeficiency states termed primary HLH -with radically different therapy strategies in both situations. COVID-19 infection with MAS typically occurs in subjects with adult respiratory distress syndrome (ARDS) and historically, non-survival in ARDS was linked to sustained IL-6 and IL-1 elevation. We provide a model for the classification of MAS to stratify the MAS-like presentation in COVID-19 pneumonia and explore the complexities of discerning ARDS from MAS. We discuss the potential impact of timing of anti-cytokine therapy on viral clearance and the impact of such therapy on intra-pulmonary macrophage activation and emergent pulmonary vascular disease.

Hemophagocytic lymphohistiocytosis: An update on pathogenesis, diagnosis, and therapy

Hemophagocytic lymphohistiocytosis (HLH) is a rare, life-threatening state of immune hyperactivation that arises in the setting of genetic mutations and infectious, inflammatory, or neoplastic triggers. Sustained, aberrant activation of cytotoxic CD8⁺ T cells and resultant inflammatory cytokine release are core pathogenic mechanisms. Key clinical features include high persistent fever, hepatosplenomegaly, blood cytopenia, elevated aminotransferase and ferritin levels, and coagulopathy. HLH is likely under-recognized, and mortality remains high, especially in adults; thus, prompt diagnosis and treatment are essential. Familial forms of HLH are currently treated with chemotherapy as a bridge to hematopoietic stem cell transplantation. HLH occurring in rheumatic disease (macrophage activation syndrome) is treated with glucocorticoids, IL-1 blockade, or cyclosporine A. In other forms of HLH, addressing the underlying trigger is essential. There remains a pressing need for more sensitive, context-specific diagnostic tools. Safer, more effective therapies will arise with improved understanding of the cellular and molecular mechanisms of HLH.

Pediatric macrophage activation syndrome, recognizing the tip of the Iceberg

Macrophage activation syndrome (MAS) is the name given to secondary hemophagocytic lymphohistiocytosis (sHLH) associated with rheumatic diseases. Previously, MAS has been best studied in children with systemic juvenile idiopathic arthritis (sJIA), who are at high risk of developing MAS. MAS/sHLH is a cytokine storm that results in multi-organ system failure and is frequently fatal. Early diagnosis and treatment is critical for improving survival. Various diagnostic tools have been developed for identifying MAS in the setting of sJIA, as well as for all forms of MAS/sHLH. These are largely based on clinical (e.g., fever) and laboratory features (e.g., cytopenias). None are perfectly sensitive and specific, however, increasing awareness of this condition is also paramount in making the diagnosis. Rare familial forms of HLH can also be diagnosed based on homozygous mutation in genes largely involved in perforin-mediated cytolytic function of lymphocytes (natural killer cells and CD8 T cells). Intriguingly, heterozygous defects in these same genes are frequently identified in patients with sHLH and MAS. Decreased cytolytic function results in prolonged interaction of the lytic lymphocytes and their target antigen presenting cells, thus resulting in the pro-inflammatory cytokine storm believed responsible for the multi-organ failure. Novel cytokine-targeted therapies are currently being explored for a less toxic yet effective alternative to chemotherapeutic approaches to treating children with sHLH/MAS. As increased recognition and diagnosis of MAS is on the rise, an earlier and cytokine-targeted approach to therapy will likely save many lives of children with this disorder.

Clinical and laboratory features, treatment, and outcomes of macrophage activation syndrome in 80 children: a multi-center study in China

BACKGROUND

Macrophage activation syndrome (MAS) is a major cause of morbidity and mortality in pediatric rheumatology. We aimed to further understand the clinical features, treatment, and outcome of MAS in China.

METHODS

A multi-center cohort study was performed in seven hospitals in China from 2012 to 2018. Eighty patients with MAS were enrolled, including 53 cases with systemic juvenile idiopathic arthritis (SJIA-MAS), 10 cases of Kawasaki disease (KD-MAS), and 17 cases of connective tissue disease (CTD-MAS). The clinical and laboratory data were collected before (pre-), at onset, and during full-blown stages of MAS. We compared the data among the SJIA-MAS, KD-MAS, and CTD-MAS subjects.

RESULTS

51.2% of patients developed MAS when the underlying disease was first diagnosed. In patients with SJIA, 22.6% (12/53) were found to have hypotension before the onset of SJIA-MAS. These patients were also found to have significantly increased aspartate aminotransferase (AST) and lactate dehydrogenase (LDH), as well as decreased albumin (P < 0.05), but no difference in alanine aminotransferase, ferritin, and ratio of ferritin/erythrocyte sedimentation rate (ESR) at onset of MAS when compared to pre-MAS stages of the disease. In addition, ferritin and ratio of ferritin/ESR were significantly elevated in patients at full-blown stages of SJIA-MAS compared to pre-MAS stage. Significantly increased ferritin and ratio of ferritin/ESR were also observed in patients with SJIA compared to in KD and CTD. Receiver-operating characteristic analysis showed that 12,217.5 μg/L of ferritin and 267.5 of ferritin/ESR ratio had sensitivity (80.0% and 90.5%) and specificity (88.2% and 86.7%), respectively, for predicting full-blown SJIA-MAS. The majority of the patients received corticosteroids (79/80), while biologic agents were used in 12.5% (10/80) of cases. Tocilizumab was the most commonly selected biologic agent. The overall mortality rate was 7.5%.

CONCLUSIONS

About half of MAS occurred when the underlying autoimmune diseases (SJIA, KD, and CTD) were first diagnosed. Hypotension could be an important manifestation before MAS diagnosis. Decreased albumin and increased AST, LDH, ferritin, and ratio of ferritin/ESR could predict the onset or full blown of MAS in patient with SJIA.

[Adult-onset Still's disease complications]

Adult-onset Still's disease (AOSD), first described in 1971 by Bywaters, is a rare systemic auto-inflammatory disorder of unknown etiology, characterized by a symptomatic triad associating prolonged fever, polyarthritis and rash. The management of this disease has significantly improved since its first description, and, although the overall prognosis of the AOSD is good, with a low attributable mortality, below 3% (but up to 18% depending on the series), some rare complications are still possible, can be life-threatening and change the prognosis of the disease. A literature search was performed to review AOSD's complications: reactive hemophagocytic lymphohystiocytosis, coagulation disorders, fulminant hepatitis, cardiovascular (pericarditis, myocarditis, HTAP) or pulmonary complications, neurologic, renal complications, and AA amyloidosis. For most of AOSD-related complications, corticosteroids remain the first-line treatment, in association with supportive care measures in case of severe complications. In case of inadequate response, multidisciplinary care with concil from a referral center is advised, and IL-1 or IL-6 blockers, but also ciclosporine, are the molecule to use in second intention.

Tocilizumab modifies clinical and laboratory features of macrophage activation syndrome complicating systemic juvenile idiopathic arthritis

BACKGROUND

This study aimed to determine the influence of tocilizumab (TCZ) in modifying the clinical and laboratory features of macrophage activation syndrome (MAS) complicating systemic juvenile idiopathic arthritis (s-JIA). Furthermore, we assessed the performance of the 2016 MAS classification criteria for patients with s-JIA-associated MAS while treated with TCZ.

METHODS

A panel of 15 pediatric rheumatologists conducted a combination of expert consensus and analysis of real patient data. Clinical and laboratory features of s-JIA-associated MAS in 12 TCZ-treated patients and 18 untreated patients were evaluated. Possible MAS was defined as having characteristic laboratory features but lack of clinical features of MAS, or atypical MAS, or early treatment that prevented full-blown MAS.

RESULTS

Clinically, the TCZ-treated patients with s-JIA-associated MAS were less likely febrile and had significantly lower ferritin, triglyceride, and CRP levels than the untreated patients with s-JIA-associated MAS. Other laboratory features of MAS including lower platelet counts and lower fibrinogen were more pronounced in TCZ-treated patients. The TCZ-treated patients with s-JIA-associated MAS were less likely to be classified as MAS based on the MAS classification criteria (25% vs 83.3%, p < 0.01). This is ascribed to the absence of fever or insufficient ferritin elevation, compared with the untreated patients.

CONCLUSION

TCZ could modify the clinical and laboratory features of s-JIA-associated MAS. When evaluating the s-JIA patients while treated with TCZ, it is not applicable to use MAS classification criteria. Care must be taken to not underdiagnose MAS based on the MAS classification criteria.

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.

Systemic Juvenile Idiopathic Arthritis-Associated Lung Disease: Characterization and Risk Factors

OBJECTIVE

Systemic juvenile idiopathic arthritis (JIA) is associated with a recently recognized, albeit poorly defined and characterized, lung disease (LD). The objective of this study was to describe the clinical characteristics, risk factors, and histopathologic and immunologic features of this novel inflammatory LD associated with systemic JIA (designated SJIA-LD).

METHODS

Clinical data collected since 2010 were abstracted from the medical records of patients with systemic JIA from the Cincinnati Children's Hospital Medical Center. Epidemiologic, cellular, biochemical, genomic, and transcriptional profiling analyses were performed.

RESULTS

Eighteen patients with SJIA-LD were identified. Radiographic findings included diffuse ground-glass opacities, subpleural reticulation, interlobular septal thickening, and lymphadenopathy. Pathologic findings included patchy, but extensive, lymphoplasmacytic infiltrates and mixed features of pulmonary alveolar proteinosis (PAP) and endogenous lipoid pneumonia. Compared to systemic JIA patients without LD, those with SJIA-LD were younger at the diagnosis of systemic JIA (odds ratio [OR] 6.5, P = 0.007), more often had prior episodes of macrophage activation syndrome (MAS) (OR 14.5, P < 0.001), had a greater frequency of adverse reactions to biologic therapy (OR 13.6, P < 0.001), and had higher serum levels of interleukin-18 (IL-18) (median 27,612 pg/ml versus 5,413 pg/ml; P = 0.047). Patients with SJIA-LD lacked genetic, serologic, or functional evidence of granulocyte-macrophage colony-stimulating factor pathway dysfunction, a feature that is typical of familial or autoimmune PAP. Moreover, bronchoalveolar lavage (BAL) fluid from patients with SJIA-LD rarely demonstrated proteinaceous material and had less lipid-laden macrophages than that seen in patients with primary PAP (mean 10.5% in patients with SJIA-LD versus 66.1% in patients with primary PAP; P < 0.001). BAL fluid from patients with SJIA-LD contained elevated levels of IL-18 and the interferon-γ-induced chemokines CXCL9 and CXCL10. Transcriptional profiling of the lung tissue from patients with SJIA-LD identified up-regulated type II interferon and T cell activation networks. This signature was also present in SJIA-LD human lung tissue sections that lacked substantial histopathologic findings, suggesting that this activation signature may precede and drive the lung pathology in SJIA-LD.

CONCLUSION

Pulmonary disease is increasingly detected in children with systemic JIA, particularly in association with MAS. This entity has distinct clinical and immunologic features and represents an uncharacterized inflammatory LD.

Interleukin-6 in juvenile idiopathic arthritis

Juvenile idiopathic arthritis (JIA) is a chronic childhood arthritis. Its pathogenesis is very complicated, with the involvement of not only immune cells but various types of parenchymal cells, and is affected by both genetic and environmental predispositions. The clinical spectrum from inflammation to related conditions is largely mediated by cytokines including interleukin (IL)-6. Fluctuations in IL-6 and its related molecules can modulate the pathogenesis and the clinical presentation positively or negatively. The recent clinical impact of IL-6 blockade on JIA has begun a therapeutic paradigm shift. This review describes the characteristics of JIA, mainly focused on IL-6 with the current therapeutic perspective.

Calm in the midst of cytokine storm: a collaborative approach to the diagnosis and treatment of hemophagocytic lymphohistiocytosis and macrophage activation syndrome

BACKGROUND

Hemophagocytic lymphohistiocytosis (HLH) and macrophage activation syndrome (MAS) were historically thought to be distinct entities, often managed in isolation. In fact, these conditions are closely related. A collaborative approach, which incorporates expertise from subspecialties that previously treated HLH/MAS independently, is needed. We leveraged quality improvement (QI) techniques in the form of an Evidence-Based Guideline (EBG) to build consensus across disciplines on the diagnosis and treatment of HLH/MAS.

METHODS

A multidisciplinary work group was convened that met monthly to develop the HLH/MAS EBG. Literature review and expert opinion were used to develop a management strategy for HLH/MAS. The EBG was implemented, and quality metrics were selected to monitor outcomes.

RESULTS

An HLH/MAS clinical team was formed with representatives from subspecialties involved in the care of patients with HLH/MAS. Broad entry criteria for the HLH/MAS EBG were established and included fever and ferritin ≥500 ng/mL. The rheumatology team was identified as the "gate-keeper," charged with overseeing the diagnostic evaluation recommended in the EBG. First-line medications were recommended based on the acuity of illness and risk of concurrent infection. Quality metrics to be tracked prospectively based on time to initiation of treatment and clinical response were selected.

CONCLUSION

HLH/MAS are increasingly considered to be a spectrum of related conditions, and joint management across subspecialties could improve patient outcomes. Our experience in creating a multidisciplinary approach to HLH/MAS management can serve as a model for care at other institutions.

The Immunology of Macrophage Activation Syndrome

Synonymous with secondary hemophagocytic lymphohistiocytosis, macrophage activation syndrome (MAS) is a term used by rheumatologists to describe a potentially life-threatening complication of systemic inflammatory disorders, most commonly systemic juvenile idiopathic arthritis (sJIA) and systemic lupus erythematosus (SLE). Clinical and laboratory features of MAS include sustained fever, hyperferritinemia, pancytopenia, fibrinolytic coagulopathy, and liver dysfunction. Soluble interleukin-2 receptor alpha chain (sCD25) and sCD163 may be elevated, and histopathology often reveals characteristic increased hemophagocytic activity in the bone marrow (and other tissues), with positive CD163 (histiocyte) staining. A common hypothesis as to the pathophysiology of many cases of MAS proposes a defect in lymphocyte cytolytic activity. Specific heterozygous gene mutations in familial HLH-associated cytolytic pathway genes (e.g., PRF1, UNC13D) have been linked to a substantial subset of MAS patients. In addition, the pro-inflammatory cytokine environment, particularly IL-6, has been shown to decrease NK cell cytolytic function. The inability of NK cells and cytolytic CD8 T cells to lyse infected and otherwise activated antigen presenting cells results in prolonged cell-to-cell (innate and adaptive immune cells) interactions and amplification of a pro-inflammatory cytokine cascade. The cytokine storm results in activation of macrophages, causing hemophagocytosis, as well as contributing to multi-organ dysfunction. In addition to macrophages, dendritic cells likely play a critical role in antigen presentation to cytolytic lymphocytes, as well as contributing to cytokine expression. Several cytokines, including tumor necrosis factor, interferon-gamma, and numerous interleukins (i.e., IL-1, IL-6, IL-18, IL-33), have been implicated in the cytokine cascade. In addition to broadly immunosuppressive therapies, novel cytokine targeted treatments are being explored to dampen the overly active immune response that is responsible for much of the pathology seen in MAS.