Performance of current guidelines for diagnosis of macrophage activation syndrome complicating systemic juvenile idiopathic arthritis

Differences and similarities in cytokine profiles of macrophage activation syndrome in systemic lupus erythematosus and adult-onset Still's disease

To clarify the differences and similarities in the cytokine profiles of macrophage activating syndrome (MAS) between systemic lupus erythematosus (SLE) and adult-onset Still's disease (AOSD). The study participants included 9 patients with MAS-SLE, 22 with non-MAS-SLE, 9 with MAS-AOSD, and 13 with non-MAS-AOSD. Serum cytokine levels were measured using a multiplex bead assay. Cytokine levels were compared between patients with SLE and AOSD with/without MAS. Moreover, cytokine patterns were examined using principal component analysis (PCA) and cluster analysis. IL-6, IL-8, IL-18, and TNF-α levels were elevated in patients with SLE and AOSD. IFN-α levels were elevated in SLE, whereas IL-1β and IL-18 levels were elevated in AOSD. In SLE, IFN-α and IL-10 levels were higher in MAS than in non-MAS and controls. PCA revealed distinctive cytokine patterns in SLE and AOSD, SLE with IFN-α and IP-10, AOSD with IL-1β, IL-6, and IL-18, and enhanced cytokine production in MAS. PCA and cluster analysis showed no differences in cytokine patterns between the MAS and non-MAS groups. However, serum ferritin levels were correlated with IFN-α levels in SLE. Cytokine profiles differed between SLE and AOSD but not between MAS and non-MAS. MAS is induced by the enhancement of underlying cytokine abnormalities rather than by MAS-specific cytokine profiles. Type I IFN may be involved in MAS development in patients with SLE.

Approaching hemophagocytic lymphohistiocytosis

Hemophagocytic Lymphohistiocytosis (HLH) is a rare clinical condition characterized by sustained but ineffective immune system activation, leading to severe and systemic hyperinflammation. It may occur as a genetic or sporadic condition, often triggered by an infection. The multifaceted pathogenesis results in a wide range of non-specific signs and symptoms, hampering early recognition. Despite a great improvement in terms of survival in the last decades, a considerable proportion of patients with HLH still die from progressive disease. Thus, prompt diagnosis and treatment are crucial for survival. Faced with the complexity and the heterogeneity of syndrome, expert consultation is recommended to correctly interpret clinical, functional and genetic findings and address therapeutic decisions. Cytofluorimetric and genetic analysis should be performed in reference laboratories. Genetic analysis is mandatory to confirm familial hemophagocytic lymphohistiocytosis (FHL) and Next Generation Sequencing is increasingly adopted to extend the spectrum of genetic predisposition to HLH, though its results should be critically discussed with specialists. In this review, we critically revise the reported laboratory tools for the diagnosis of HLH, in order to outline a comprehensive and widely available workup that allows to reduce the time between the clinical suspicion of HLH and its final diagnosis.

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.

Multisystem Inflammatory Syndrome in a Young Adult (MIC-A) Following SARS-CoV-2 Infection

Multisystem Inflammatory Syndrome (MIS) is a rare but increasingly recognized complication of SARS-CoV-2 infection, usually presenting 2 to 6 weeks after the onset of COVID-19 infection symptoms and affecting mainly children. However, there have been reported several cases of a similar multisystem inflammatory syndrome in adults (MIS-A). We describe the case of a previously healthy 28-year-old male who presented with a clinical profile with multiorgan involvement within four weeks after confirmed SARS-CoV-2 infection, suggestive for multisystem inflammatory syndrome (MIS-A). The clinical presentation included persistent high grade of fever, gastrointestinal and mucocutaneous lesions, lymphadenopathy, elevated cardiac and inflammatory biomarkers, cytopenia and shock. This case report illustrates the wide range of presentations, diagnosis, and treatment modalities of multisystem inflammatory syndrome. The pathophysiology and the mechanisms by which SARS-CoV-2 triggers an abnormal immune response leading to MIS remain poorly understood. Better characterization of MIS-A and early recognition of MIS is important because it is associated with high mortality if left untreated.

Infection-Triggered Hyperinflammatory Syndromes in Children

An association between infectious diseases and macrophage activation syndrome (MAS) has been reported, yet the exact role of infection in MAS development is still unclear. Here, a retrospective analysis of the clinical records of patients with rheumatic diseases complicated with MAS who were treated in a pediatric tertiary care center between 2011 and 2020 was performed. Any infection documented within the 30 days preceding the onset of MAS was reported. Out of 125 children in follow-up for systemic rheumatic diseases, 12 developed MAS, with a total of 14 episodes. One patient experienced three episodes of MAS. Clinical and/or laboratory evidence of infection preceded the onset of MAS in 12 events. Clinical features, therapeutic strategies, and patient outcomes were described. The aim of this study was to evaluate the possible role of infection as a relevant trigger for MAS development in children with rheumatic conditions. The pathogenetic pathways involved in the cross-talk between uncontrolled inflammatory activity and the immune response to infection deserve further investigation.

Immunotherapy of COVID-19: Inside and Beyond IL-6 Signalling

Acting on the cytokine cascade is key to preventing disease progression and death in hospitalised patients with COVID-19. Among anti-cytokine therapies, interleukin (IL)-6 inhibitors have been the most used and studied since the beginning of the pandemic. Going through previous observational studies, subsequent randomised controlled trials, and meta-analyses, we focused on the baseline characteristics of the patients recruited, identifying the most favourable features in the light of positive or negative study outcomes; taking into account the biological significance and predictivity of IL-6 and other biomarkers according to specific thresholds, we ultimately attempted to delineate precise windows for therapeutic intervention. By stimulating scavenger macrophages and T-cell responsivity, IL-6 seems protective against viral replication during asymptomatic infection; still protective on early tissue damage by modulating the release of granzymes and lymphokines in mild-moderate disease; importantly pathogenic in severe disease by inducing the proinflammatory activation of immune and endothelial cells (through trans-signalling and trans-presentation); and again protective in critical disease by exerting homeostatic roles for tissue repair (through cis-signalling), while IL-1 still drives hyperinflammation. IL-6 inhibitors, particularly anti-IL-6R monoclonal antibodies (e.g., tocilizumab, sarilumab), are effective in severe disease, characterised by baseline IL-6 concentrations ranging from 35 to 90 ng/mL (reached in the circulation within 6 days of hospital admission), a ratio of partial pressure arterial oxygen (PaO2) and fraction of inspired oxygen (FiO2) between 100 and 200 mmHg, requirement of high-flow oxygen or non-invasive ventilation, C-reactive protein levels between 120 and 160 mg/L, ferritin levels between 800 and 1600 ng/mL, D-dimer levels between 750 and 3000 ng/mL, and lactate dehydrogenase levels between 350 and 500 U/L. Granulocyte-macrophage colony-stimulating factor inhibitors might have similar windows of opportunity but different age preferences compared to IL-6 inhibitors (over or under 70 years old, respectively). Janus kinase inhibitors (e.g., baricitinib) may also be effective in moderate disease, whereas IL-1 inhibitors (e.g., anakinra) may also be effective in critical disease. Correct use of biologics based on therapeutic windows is essential for successful outcomes and could inform future new trials with more appropriate recruiting criteria.

Clinical characteristics of children with MIS-C fulfilling classification criteria for macrophage activation syndrome

BACKGROUND

Macrophage activation syndrome (MAS) is a potentially life-threatening complication of various inflammatory disorders, including multisystem inflammatory syndrome in children (MIS-C). MIS-C refractory to treatment should raise suspicion of MAS, which can be fatal if a definitive diagnosis is delayed. Unfortunately, there is a lack of data on MAS in children with MIS-C.

OBJECTIVE

Our study aims to analyze the risk factors for the development of MAS in MIS-C, its clinical course and response to treatment, and identify predictive factors for pediatric intensive care.

MATERIAL AND METHODS

We analyzed data from the Polish MIS-C registry of the MultiOrgan Inflammatory Syndromes COVID-19 Related Study. Patients were diagnosed according to the WHO MIS-C definition and treated according to national guidelines (Polish Pediatric Society) based on international consensus. MAS definition was based on 2016 Classification Criteria for Macrophage Activation Syndrome Complicating Systemic Juvenile Idiopathic Arthritis.

RESULTS

Two-hundred and seventy four children met the study inclusion criteria. Fifty-nine patients fulfilled MAS classification criteria, nine of which required admission to the pediatric intensive care unit (PICU). MIS-C patients with MAS were significantly older than patients without MAS (median 11.2 vs. 8.1 years). Multivariable analysis showed that age, symptoms characteristic of atypical Kawasaki disease, and skin erosions were significant factors associated with MAS in MIS-C patients. Analysis of laboratory parameters showed that on admission, MIS-C patients with MAS had significantly lower median lymphocyte and platelet counts, albumin and sodium levels, and higher median levels of C-reactive protein, procalcitonin, ferritin, D-dimers, triglycerides, serum creatinine, urea, and γ-glutamyl transpeptidase, and neutrophil count. Multivariate analysis showed that higher procalcitonin, ferritin, and fibrinogen levels at admission were predictive of MAS. Only elevated troponin level was a factor indicating a requirement of PICU hospitalization for children with MAS. MIS-C patients fulfilling MAS criteria were treated more often with intravenous immunoglobulins and steroids than children without MAS. Children with MAS more often required mechanical ventilation. None of the patients required biological agents.

CONCLUSIONS

The clinical course of MAS in MIS-C seems milder, treatment less aggressive, and the prognosis better than expected based on the current knowledge on MAS complicating other rheumatological diseases.

Thrombotic Microangiopathy Associated with Macrophage Activation Syndrome: A Multinational Study of 23 Patients

OBJECTIVE

To describe the clinical characteristics, treatment, and outcomes of a multinational cohort of patients with macrophage activation syndrome (MAS) and thrombotic microangiopathy (TMA).

STUDY DESIGN

International pediatric rheumatologists were asked to collect retrospectively the data of patients with the co-occurrence of MAS and TMA. Clinical and laboratory features of patients with systemic juvenile idiopathic arthritis (sJIA)-associated MAS and TMA were compared with those of an historical cohort of patients with sJIA and MAS.

RESULTS

Twenty-three patients with MAS and TMA were enrolled: 17 had sJIA, 2 systemic lupus erythematosus, 1 juvenile dermatomyositis, 1 mixed connective tissue disease, and 2 undifferentiated connective tissue disease. Compared with the historical cohort of MAS, patients with sJIA with coexistent MAS and TMA had higher frequencies of renal failure and neurologic involvement, hemorrhage, jaundice, and respiratory symptoms, as well as more severe anemia and thrombocytopenia, higher levels of alanine aminotransferase, lactate dehydrogenase, bilirubin and D-dimer, and lower levels of albumin and fibrinogen. They also required admission to the intensive care unit more frequently. Among patients tested, complement abnormalities and reduced ADAMTS13 activity were observed in 64.3% and 44.4% of cases, respectively. All patients received glucocorticoids. Treatment for TMA included plasma-exchange, eculizumab, and rituximab.

CONCLUSIONS

The possible coexistence of MAS and TMA in rheumatic diseases may be underrecognized. This association should be considered in patients with MAS who develop disproportionate anemia, thrombocytopenia, and lactate dehydrogenase increase, or have multiorgan failure.

Sudden Hypotension and Increased Serum Interferon-γ and Interleukin-10 Predict Early Macrophage Activation Syndrome in Patients with Systemic Juvenile Idiopathic Arthritis

OBJECTIVE

To identify clinical and laboratory predictors for early macrophage activation syndrome (MAS) associated with systemic juvenile idiopathic arthritis (sJIA).

STUDY DESIGN

This is a retrospective cohort study of 149 patients with sJIA, of whom 27 had 31 episodes of MAS. We evaluated the clinical and laboratory features of patients with sJIA and MAS and compared them with those without MAS. We focused our analysis on the overall process of MAS development, especially MAS onset.

RESULTS

As shown in previous studies, we found a high percentage of fever, absence of arthritis, and central nervous system dysfunction at MAS onset in our study cohort. We also found that 35% of patients with MAS had hypotension although not shock, and 22.6% of patients with MAS had gastrointestinal involvement at MAS onset. Compared with patients with MAS without hypotension, patients with MAS and hypotension had greater rates of admission to the intensive care unit; presented with more arthritis, serositis, pneumonia, and gastrointestinal involvement; and had greater white blood cell and absolute neutrophil counts and serum bilirubin levels and lower serum total protein. We confirmed laboratory markers such as platelet counts, lactate dehydrogenase, and aspartate aminotransferase can help to identify early MAS and that ferritin/erythrocyte sedimentation rate ratio of approximately 20.0 had a high diagnostic sensitivity and specificity for MAS. In addition, we discovered that the combination of interferon-γ >17.1 pg/mL and interleukin-10 >7.8 pg/mL appeared to be a good cytokine pattern for the recognition of MAS onset.

CONCLUSIONS

Sudden hypotension, elevated ferritin/erythrocyte sedimentation rate ratio, and the cytokine pattern of significantly increased interferon-γ and interleukin-10 levels are important markers for early identification of MAS in addition to the traditional characteristics of sJIA-associated MAS.

The combined prevalence of classified rare rheumatic diseases is almost double that of ankylosing spondylitis

BACKGROUND

Rare diseases (RDs) affect less than 5/10,000 people in Europe and fewer than 200,000 individuals in the United States. In rheumatology, RDs are heterogeneous and lack systemic classification. Clinical courses involve a variety of diverse symptoms, and patients may be misdiagnosed and not receive appropriate treatment. The objective of this study was to identify and classify some of the most important RDs in rheumatology. We also attempted to determine their combined prevalence to more precisely define this area of rheumatology and increase awareness of RDs in healthcare systems. We conducted a comprehensive literature search and analyzed each disease for the specified criteria, such as clinical symptoms, treatment regimens, prognoses, and point prevalences. If no epidemiological data were available, we estimated the prevalence as 1/1,000,000. The total point prevalence for all RDs in rheumatology was estimated as the sum of the individually determined prevalences.

RESULTS

A total of 76 syndromes and diseases were identified, including vasculitis/vasculopathy (n = 15), arthritis/arthropathy (n = 11), autoinflammatory syndromes (n = 11), myositis (n = 9), bone disorders (n = 11), connective tissue diseases (n = 8), overgrowth syndromes (n = 3), and others (n = 8). Out of the 76 diseases, 61 (80%) are classified as chronic, with a remitting-relapsing course in 27 cases (35%) upon adequate treatment. Another 34 (45%) diseases were predominantly progressive and difficult to control. Corticosteroids are a therapeutic option in 49 (64%) syndromes. Mortality is variable and could not be determined precisely. Epidemiological studies and prevalence data were available for 33 syndromes and diseases. For an additional eight diseases, only incidence data were accessible. The summed prevalence of all RDs was 28.8/10,000.

CONCLUSIONS

RDs in rheumatology are frequently chronic, progressive, and present variable symptoms. Treatment options are often restricted to corticosteroids, presumably because of the scarcity of randomized controlled trials. The estimated combined prevalence is significant and almost double that of ankylosing spondylitis (18/10,000). Thus, healthcare systems should assign RDs similar importance as any other common disease in rheumatology.

Brucellosis-Induced Hemophagocytic Lymphohistiocytosis

Hemophagocytic lymphohistiocytosis (HLH) is a fatal syndrome, which can be primary or triggered by a systemic disease or an infection. The commonly reported infectious causes of secondary HLH include Epstein-Barr virus (EBV), cytomegalovirus (CMV), mycobacterium, and leishmaniasis among other infections. In this case report, we report a 50-year-old woman with brucellosis-related HLH after presenting with prolonged fever, hepatosplenomegaly, and cytopenia.

Bidirectional association between systemic lupus erythematosus and macrophage activation syndrome: a nationwide population-based study

OBJECTIVES

To determine the bidirectional relationship between macrophage activation syndrome (MAS) and systemic lupus erythematosus (SLE).

METHODS

Using the 1997-2013 Taiwan's National Health Insurance Research Database, we identified patients with newly diagnosed SLE from 2001 to 2013 from the whole beneficiaries and selected individuals without SLE from a one-million representative population. Propensity score (PS) matching was performed to balance incident SLE patients and individuals without SLE according to age, sex, comorbidities and medical utilization. The association between a history of MAS and SLE was studied using conditional logistic regression analysis shown as adjusted odds ratio (aOR). The risk of MAS associated with SLE was analyzed using Cox proportional regression analysis shown as hazard ratio (aHR), and we conducted a sensitivity analysis using various definitions of MAS.

RESULTS

We finally included 10,481 SLE patients and 20,962 PS-matched (1:2) non-SLE individuals. The correlation between a history of MAS and SLE did not reach statistical significance after adjustment for potential confounders (aOR, 1.18; 95% confidence interval, 0.80-1.75) in the age/sex-matched populations. In the 1:2 PS-matched populations, the risk of MAS markedly increased in patients with SLE (aHR, 7.18; 95% confidence interval, 4.97-10.36). Other risk factors for MAS included female, age ≥ 65 years, low income, a history of inflammatory bowel disease, and MAS history.

CONCLUSION

This nationwide, population-based study revealed that a history of MAS was not significantly associated with SLE risk. However, the risk of MAS was markedly associated with SLE and history of MAS.

Comparison of baseline laboratory findings of macrophage activation syndrome complicating systemic juvenile idiopathic arthritis and multisystem inflammatory syndrome in children

AIMS

Recently, multisystem inflammatory syndrome in children (MIS-C) has been recognized in association with coronavirus disease 2019 as a cytokine storm syndrome. MIS-C presents with symptoms similar to Kawasaki disease and macrophage activation syndrome (MAS). We aimed to better understand this cytokine storm syndrome by comparing the initial laboratory findings of MIS-C and MAS.

METHODS

Patients who were diagnosed with MAS due to systemic juvenile idiopathic arthritis in our clinic between March 2002 and November 2020 and with MIS-C between 20 September and 20 October 2020 were enrolled into the study. The medical files of all patients were reviewed retrospectively.

RESULTS

A total of 13 MAS (9 boys, 4 girls) and 26 MIS-C (16 boys,10 girls) patients were included in the study. Hemoglobin, absolute neutrophil and lymphocyte counts, C-reactive protein (CRP), ferritin, fibrinogen and lactate dehydrogenase (LDH) levels showed significant differences between the two groups (P < 0.05). Patients with MAS had lower hemoglobin (10.10 g/dL) and fibrinogen (2.72 g/dL), but higher ferritin (17 863 mg/dL) and LDH (890.61 U/L) at the time of diagnosis. Patients with MIS-C had higher absolute neutrophil count (12 180/mm³ ) and CRP (194.23 mg/dL) values, but lower absolute lymphocyte count (1140/mm³ ) at the time of diagnosis. Left ventricle ejection fraction was significantly lower in the MIS-C group in echocardiographic evaluation (P < 0.001).

CONCLUSION

Ferritin, hemoglobin, LDH, and fibrinogen levels were significantly changed in MAS compared with MIS-C. However, patients with MIS-C have more severe signs than MAS, such as cardiac involvement.

Macrophage Activation Syndrome in Adults: A Retrospective Case Series

Macrophage activation syndrome (MAS) is a form of hemophagocytic lymphohistocytosis that occurs in patients with a variety of inflammatory rheumatologic conditions. Traditionally, it is noted in pediatric patients with systemic juvenile idiopathic arthritis and systemic lupus erythematous. It is a rapidly progressive and life-threatening syndrome of excess immune activation with an estimated mortality rate of 40% in children. It has become clear recently that MAS occurs in adult patients with underlying rheumatic inflammatory diseases. In this article, we describe 6 adult patients with likely underlying MAS. This case series will outline factors related to diagnosis, pathophysiology, and review present therapeutic strategies.

Multi-System Inflammatory Syndrome in Children (MIS-C) Following SARS-CoV-2 Infection: Review of Clinical Presentation, Hypothetical Pathogenesis, and Proposed Management

Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection may result in the multisystem inflammatory syndrome in children (MIS-C). The clinical presentation of MIS-C includes fever, severe illness, and the involvement of two or more organ systems, in combination with laboratory evidence of inflammation and laboratory or epidemiologic evidence of SARS-CoV-2 infection. Some features of MIS-C resemble Kawasaki Disease, toxic shock syndrome, and secondary hemophagocytic lymphohistiocytosis/macrophage activation syndrome. The relationship of MIS-C to SARS-CoV-2 infection suggests that the pathogenesis involves post-infectious immune dysregulation. Patients with MIS-C should ideally be managed in a pediatric intensive care environment since rapid clinical deterioration may occur. Specific immunomodulatory therapy depends on the clinical presentation. The relationship between the immune response to SARS-CoV-2 vaccines in development and MIS-C requires further study.

Systemic autoinflammatory diseases

Systemic autoinflammatory diseases (SAIDs) are a growing group of disorders caused by a dysregulation of the innate immune system leading to episodes of systemic inflammation. In 1997, MEFV was the first gene identified as disease causing for Familial Mediterranean Fever, the most common hereditary SAID. In most cases, autoinflammatory diseases have a strong genetic background with mutations in single genes. Since 1997 more than 30 new genes associated with autoinflammatory diseases have been identified, affecting different parts of the innate immune system. Nevertheless, for at least 40-60% of patients with phenotypes typical for SAIDs, a distinct diagnosis cannot be met, leading to undefined SAIDs (uSAIDs). However, SAIDs can also be of polygenic or multifactorial origin, with environmental influence modulating the phenotype. The implementation of a disease continuum model combining the adaptive and the innate immune system with autoinflammatory and autoimmune diseases shows the complexity of SAIDs and the importance of new methods to elucidate molecular changes and causative factors in SAIDs. Diagnosis is often based on clinical presentation and genetic testing. The timeline from onset to diagnosis takes up to 7.3 years, highlighting the indisputable need to identify new treatment and diagnostic targets. Recently, other factors are under investigation as additional contributors to the pathogenesis of SAIDs. This review gives an overview of pathogenesis and etiology of SAIDs, and summarizes recent diagnosis and treatment options.

Macrophage Activation Syndrome and Secondary Hemophagocytic Lymphohistiocytosis in Childhood Inflammatory Disorders: Diagnosis and Management

Macrophage activation syndrome (MAS), a form of secondary hemophagocytic lymphohistiocytosis, is a frequently fatal complication of a variety of pediatric inflammatory disorders. MAS has been most commonly associated with systemic juvenile idiopathic arthritis (sJIA), as approximately 10% of children with sJIA develop fulminant MAS, with another 30-40% exhibiting a more subclinical form of the disease. Children with other rheumatologic conditions such as systemic lupus erythematosus and Kawasaki disease are also at risk for MAS. Moreover, MAS also complicates various genetic autoinflammatory disorders such as gain of function mutations in the cytosolic inflammasome NLRC4, pediatric hematologic malignancies (e.g., T-cell lymphoma), and primary immunodeficiencies characterized by immune dysregulation. Disease-specific and broadly inclusive diagnostic criteria have been developed to facilitate the diagnosis of MAS. Recently, simple screening tools such as the serum ferritin to erythrocyte sedimentation rate ratio have been proposed. Early diagnosis and rapid initiation of immunosuppression are essential for the effective management of MAS. With a better understanding of the pathophysiology of MAS and the advent of novel therapeutics, a broad immunosuppressive approach to treatment is giving way to targeted anti-cytokine therapies. These treatments include agents that block interleukin-1 (IL-1), IL-6, IL-18, interferon-γ, as well as inhibitors of downstream targets of cytokine signaling (e.g., Janus kinases). Increased early recognition of MAS among pediatric inflammatory disorders combined with the use of effective and less toxic cytokine-targeted therapies should lower the mortality of this frequently fatal disorder.

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.

Macrophage activation syndrome in pediatrics

Macrophage activation syndrome (MAS) is a serious, potentially life-threatening, hyperinflammatory condition, which belongs to the spectrum of hemophagocytic lymphohistiocytosis (HLH) and can complicate several immunologic and rheumatic disorders. MAS is characterized by a dysfunctional immune response that is similar to that seen in other forms of HLH. Because MAS may pursue a rapidly fatal course, prompt recognition of its clinical and laboratory features and immediate therapeutic intervention are fundamental. Recently, a set of classification criteria for MAS complicating sJIA has been developed through a multinational collaborative effort. High-dose parenteral corticosteroids remain the mainstay of treatment of MAS.

Benefit of Anakinra in Treating Pediatric Secondary Hemophagocytic Lymphohistiocytosis

OBJECTIVE

To assess the benefit of the recombinant human interleukin-1 receptor antagonist anakinra in treating pediatric patients with secondary hemophagocytic lymphohistiocytosis (HLH)/macrophage activation syndrome (MAS) associated with rheumatic and nonrheumatic conditions.

METHODS

A retrospective chart review of all anakinra-treated patients with secondary HLH/MAS was performed at Children's of Alabama from January 2008 through December 2016. Demographic, clinical, laboratory, and genetic characteristics, outcomes data, and information on concurrent treatments were collected from the records and analyzed using appropriate univariate statistical approaches to assess changes following treatment and associations between patient variables and outcomes.

RESULTS

Forty-four patients with secondary HLH/MAS being treated with anakinra were identified in the electronic medical records. The median duration of hospitalization was 15 days. The mean pretreatment serum ferritin level was 33,316 ng/ml and dropped to 14,435 ng/ml (57% decrease) within 15 days of the start of anakinra treatment. The overall mortality rate in the cohort was 27%. Earlier initiation of anakinra (within 5 days of hospitalization) was associated with reduced mortality (P = 0.046), whereas thrombocytopenia (platelet count <100,000/μl) and STXBP2 mutations were both associated with increased mortality (P = 0.008 and P = 0.012, respectively). In considering patients according to their underlying diagnosis, those with systemic juvenile idiopathic arthritis (JIA) had the lowest mortality rate, with no deaths among the 13 systemic JIA patients included in the study (P = 0.006). In contrast, those with an underlying hematologic malignancy had the highest mortality rate, at 100% (n = 3).

CONCLUSION

These findings suggest that anakinra appears to be effective in treating pediatric patients with non-malignancy-associated secondary HLH/MAS, especially when it is given early in the disease course and when administered to patients who have an underlying rheumatic disease.

Efficient management of secondary haemophagocytic lymphohistiocytosis with intravenous steroids and γ-immunoglobulin infusions

BACKGROUND

Secondary haemophagocytic lymphohistiocytosis (sHLH) is a rare life-threatening condition mainly associated with underlying infections, malignancies, and autoimmune or immune-mediated diseases.

AIM

To analyse all sHLH cases that were diagnosed and managed under real-world circumstances in our department focusing on the treatment schedule and the outcome.

METHODS

Prospectively collected data from all adult patients fulfilling the criteria of sHLH who diagnosed and managed from January 1, 2010 to June 1, 2018, in our department of the tertiary care university hospital of Larissa, Greece, were analysed retrospectively (n = 80; 52% male; median age: 55 years). The electronic records and/or written charts of the patients were reviewed for the demographic characteristics, clinical manifestations, underlying causes of sHLH, laboratory parameters, treatment schedule and 30-d-mortality rate. Most of patients had received after consent intravenous γ-immunoglobulin (IVIG) for 5 d (total dose 2 g/kg) in combination with intravenous steroid pulses followed by gradual tapering of prednisolone.

RESULTS

Seventy-five patients (94%) reported fever > 38.5 °C, 47 (59%) had liver or spleen enlargement and 76 (95%) had ferritin > 500 ng/mL including 20 (25%) having considerably high levels (> 10000 ng/mL). Anaemia and thrombocytopenia occurred in 72% and leucopoenia in 47% of them. Underlying infections were diagnosed in 59 patients (74%) as follows: leishmaniasis alone in 15/80 (18.9%), leishmaniasis concurrently with Coxiella Burnetti or non-Hodgkin lymphoma in 2/80 (2.5%), bacterial infections in 14/80 (17.5%) including one case with concurrent non-Hodgkin lymphoma, viral infections in 13/80 (16.3%), fungal infections in 2/80 (2.5%), infections by mycobacteria in 1/80 (1.3%) and unidentified pathogens in 12/80 (15%). Seventy-two patients (90%) had received combination treatment with IVIG and intravenous steroids. Overall, sHLH resolved in 76% of patients, 15% died within the first month but 82.5% of patients were still alive 6 mo after diagnosis. Univariate analysis showed older age, anaemia, thrombocytopenia, low fibrinogen, disseminated intravascular coagulation (DIC), and delay of diagnosis as factors that negatively affected remission. However, multivariate analysis showed low platelets and DIC as the only independent predictors of adverse outcome.

CONCLUSION

sHLH still carries a remarkable morbidity and mortality. Underlying infections were the major cause and therefore, they should be thoroughly investigated in patients with sHLH. Early recognition and combination treatment with IVIG and corticosteroids seem an efficient treatment option with successful outcome in this life-threatening condition.

New Onset Autoimmune Disease or Macrophage Activation Syndrome?

Macrophage activation syndrome (MAS) is a potentially life-threatening condition that may complicate many pediatric rheumatologic diseases. Because of its similarity in presentation to other conditions with overlapping manifestations, such as flares of rheumatologic disease or systemic infection, and the fact that there exists no single pathognomonic clinical finding or laboratory parameter to aid in diagnosis, MAS presents a significant diagnostic challenge to the practicing pediatrician with limited access to consulting pediatric rheumatologists. Along with a review of the physiology and manifestations of the condition, we have included the most current consensus for diagnosing MAS. [Pediatr Ann. 2019;48(10):e395-e399.].

Macrophage activation syndrome in juvenile dermatomyositis: a systematic review

Macrophage activation syndrome (MAS) is a potentially fatal complication of a number of rheumatological conditions, but few studies assessed it in juvenile dermatomyositis (JDM). Indeed, MAS is not considered as a frequent complication of JDM, but its occurrence could be under-estimated. In order to address this issue, we performed a revision of the available medical literature, describing and assessing patients with both MAS and JDM. After retrieving 253 records initially, 11 papers were selected as appropriate for our research objective, which provided a total of 12 patients affected with both MAS and JDM. Our pooled case series suggested that MAS in JDM may not be very rare, even though no final conclusion about its incidence and mortality rate can be made. However, JDM-related MAS seems to be difficult to treat, since methylprednisolone pulse therapy alone was not sufficient in most cases. Moreover, MAS in JDM patients often occurred at the onset of the rheumatic disease, before the final diagnosis of JDM could be established. Finally, MAS criteria validated for systemic Juvenile Idiopathic Arthritis (sJIA) resulted to be a very useful guidance to diagnose MAS in JDM patients as well, but their reliability may not be absolute. Therefore, cohort and multicenter studies are needed to assess the incidence and improve the diagnostic criteria for MAS in JDM patients.

Pediatric rheumatologic diseases: A review for primary care NPs

Rheumatologic diseases are uncommon in children but have the potential for significant morbidity, mortality, and disability. This article reviews the most common rheumatologic diseases in children, their diagnostic evaluations, and the NP's role in the management and coordination of these conditions.

Ferritin to Erythrocyte Sedimentation Rate Ratio: Simple Measure to Identify Macrophage Activation Syndrome in Systemic Juvenile Idiopathic Arthritis

Objective

Macrophage activation syndrome (MAS) is a life-threatening complication of systemic juvenile idiopathic arthritis (sJIA). Early diagnosis is critical. Classification criteria for MAS in sJIA perform less well in the setting of cytokine-directed therapies. The goal herein was to explore a simple ratio of serum ferritin to the erythrocyte sedimentation rate (ESR) for diagnosis of MAS in the setting of sJIA, and to assess ferritin alone as a screening tool for identifying MAS of multiple etiologies.

Methods

Data from a large international cohort of sJIA patients with and without MAS, and from hospitalized patients with systemic infection (SI), were assessed for the ferritin:ESR ratio and ferritin alone to identify MAS among sJIA patients. Moreover, data from a smaller cohort of MAS patients associated with multiple etiologies and febrile hospitalized controls were explored. For both cohorts and controls, receiver operating characteristic curves (ROCs) for the ferritin:ESR ratio and ferritin alone were constructed, and areas under the curves (AUCs) were calculated. The Youden index was used to determine the optimal ferritin:ESR ratio and ferritin alone cut points for diagnosis.

Results

A ferritin:ESR ratio of 21.5 was 82% sensitive and 78% specific for diagnosing sJIA-MAS versus active sJIA without MAS. Ferritin alone with a set sensitivity of 95% (screening tool) had an 89.3% specificity of identifying all-cause MAS versus febrile hospitalized children.

Conclusion

The ferritin:ESR ratio is a practical tool for diagnosing MAS among sJIA patients, and serum ferritin alone is a remarkable screening tool for identifying MAS among febrile hospitalized children.

Development and initial validation of the MS score for diagnosis of macrophage activation syndrome in systemic juvenile idiopathic arthritis

OBJECTIVE

To develop and validate a diagnostic score that aids in identifying macrophage activation syndrome (MAS) in patients with systemic juvenile idiopathic arthritis (sJIA).

METHODS

The clinical and laboratory features of 362 patients with sJIA-associated MAS and 404 patients with active sJIA without evidence of MAS were collected in a multinational collaborative project. Eighty percent of the study population was used to develop the score and the remaining 20% constituted the validation sample. A Bayesian Model Averaging approach was used to assess the role of each clinical and laboratory variables in the diagnosis of MAS and to obtain the coefficients of selected variables. The final score, named MAS/sJIA (MS) score, resulted from the linear combination of these coefficients multiplied by the values of each variable. The cut-off that best discriminated MAS from active sJIA was calculated by means of receiver operating characteristic (ROC) curve analysis. Score performance was evaluated in both developmental and validation samples.

RESULTS

The MS score ranges from -8.4 to 41.8 and comprises seven variables: central nervous system dysfunction, haemorrhagic manifestations, active arthritis, platelet count, fibrinogen, lactate dehydrogenase and ferritin. A cut-off value ≥-2.1 revealed the best performance in discriminating MAS from active sJIA, with a sensitivity of 0.85, a specificity of 0.95 and a kappa value of 0.80. The good performance of the MS score was confirmed in the validation sample.

CONCLUSION

The MS score is a powerful and feasible tool that may assist practitioners in making a timely diagnosis of MAS in patients with sJIA.

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.

Fatal case of macrophage activation syndrome (MAS) in a patient with dermatomyositis and cytomegalovirus (CMV) viraemia

We describe a case of an adult with dermatomyositis (DM) who presents with a rash, high fevers, tachycardia and hypotension, initially concerning for an infectious aetiology or a DM flare. She was found to have cytomegalovirus viraemia which improved after starting valganciclovir. After extensive workup and lack of improvement with broad-spectrum antimicrobial therapy, intravenous immunoglobulin and steroids, the patient was diagnosed with macrophage activation syndrome after bone marrow biopsy and levels of soluble CD25 (soluble interleukin (IL)-2 receptor) and IL2 were obtained. Unfortunately, despite therapy with dexamethasone, anakinra and etoposide, the patient decompensated and the patient's family opted for comfort care. The patient subsequently expired in the intensive care unit.

Recommendations for the Use of Etoposide-Based Therapy and Bone Marrow Transplantation for the Treatment of HLH: Consensus Statements by the HLH Steering Committee of the Histiocyte Society

Hemophagocytic lymphohistiocytosis (HLH) is a life-threatening hyperinflammatory syndrome requiring aggressive immunosuppressive therapy. Following 2 large international studies mainly targeting pediatric patients with familial disease and patients without underlying chronic or malignant disease, the HLH-94 protocol is recommended as the standard of care when using etoposide-based therapy by the Histiocyte Society. However, in clinical practice, etoposide-based therapy has been widely used beyond the study inclusion criteria, including older patients and patients with underlying diseases (secondary HLH). Many questions remain around these extended indications and published reports do not address several practical issues. To tackle these concerns, the HLH Steering Committee of the Histiocyte Society decided to issue guidance for use of the HLH-94 protocol. The group convened in a structured consensus finding process to define recommendations that are based largely on expert opinion backed up by available data from the literature. The recommendations address all main elements of HLH-94 including corticosteroids, cyclosporin, etoposide, intrathecal therapy, and hematopoietic stem cell transplantation (HSCT) and consider various forms of HLH and all age groups. Aspects covered include indications, applications, dosing, side effects, duration of therapy, salvage therapy, and HSCT. These recommendations aim to provide a framework to guide treatment decisions in this severe disease.

Role of Skin Biopsies in the Diagnosis of Hemophagocytic Lymphohistiocytosis

This is a report of a 15-year-old female who presented with a skin eruption and clinical features consistent with severe sepsis and septic shock. A diagnosis of acquired hemophagocytic lymphohistiocytosis (HLH) was made and confirmed by bone marrow analysis. Skin biopsy showed hemophagocytosis and CD163-positive staining of macrophages. We briefly review the clinical, histologic, and laboratory findings of hemophagocytic lymphohistiocytosis in addition to the potential role of skin biopsies in this condition.

Macrophage Activation Syndrome

Hemophagocytic lymphohistiocytosis (HLH), or termed macrophage activation syndrome (MAS) when associated with rheumatic disorders, is a frequently fatal complication of infections, rheumatic disorders, and hematopoietic malignancies. Clinically, HLH/MAS is a life-threatening condition that is usually diagnosed among febrile hospitalized patients (children and adults) who commonly present with unremitting fever and a shock-like multiorgan dysfunction scenario. Laboratory studies reveal pancytopenia, elevated liver enzymes, elevated markers of inflammation (ESR, CRP), hyperferritinemia, and features of coagulopathy. In about 60% of cases, excess hemophagocytosis (macrophages/histiocytes engulfing other hematopoietic cell types) is noted on biopsy specimens from the bone marrow, liver, lymph nodes, and other organs. HLH/MAS has been hypothesized to occur when a threshold level of inflammation has been achieved, and genetic and environmental risk factors are believed to contribute to the hyperinflammatory state. A broad variety of infections, from viruses to fungi to bacteria, have been identified as triggers of HLH/MAS, either in isolation or in addition to an underlying inflammatory disease state. Certain infections, particularly by members of the herpesvirus family, are the most notorious triggers of HLH/MAS. Treatment for infection-triggered MAS requires therapy for both the underlying infection and dampening of the hyperactive immune response.

Effect of Biologic Therapy on Clinical and Laboratory Features of Macrophage Activation Syndrome Associated With Systemic Juvenile Idiopathic Arthritis

OBJECTIVE

To assess performance of the 2016 macrophage activation syndrome (MAS) classification criteria for patients with systemic juvenile idiopathic arthritis (JIA) who develop MAS while treated with biologic medications.

METHODS

A systematic literature review was performed to identify patients with MAS while being treated with interleukin (IL)-1 and IL-6 blocking agents. Clinical and laboratory information was compared to a large previously compiled historical cohort.

RESULTS

Eighteen publications were identified, and after removing duplicates, 35 patients treated with canakinumab and 49 patients with tocilizumab were available for analysis; 5 anakinra-treated patients were excluded due to limited numbers. MAS classification criteria were less likely to classify tocilizumab-treated patients as having MAS compared to the historical cohort or canakinumab-treated patients (56.7%, 78.5%, and 84%, respectively; P < 0.01). Patients who developed MAS while treated with canakinumab trended towards lower ferritin at MAS onset than the historical cohort (4,050 versus 5,353 ng/ml; P = 0.18) but had no differences in other cardinal clinical or laboratory features. In comparison, patients who developed MAS while treated with tocilizumab were less likely febrile and had notably lower ferritin levels (1,152 versus 5,353 ng/ml; P < 0.001). Other features of MAS were more pronounced in patients treated with tocilizumab, including lower platelet counts, lower fibrinogen, and higher aspartate aminotransferase levels. Mortality rates for patients with MAS treated with tocilizumab or canakinumab were not significantly different from the historical cohort.

CONCLUSION

These findings show substantial alterations in MAS features that may limit utility of defined criteria for diagnosis of systemic JIA patients treated with biologic agents.

The influence of various therapeutic regimens on early clinical and laboratory response and outcome of children with secondary hemophagocytic lymphohistiocytosis

INTRODUCTION

Secondary hemophagocytic lymphohistiocytosis (sHLH) is a life-threatening syndrome of severe hyperinflammation which is often triggered by infection or autoimmune disease (macrophage activation syndrome - MAS). The aim of our study was to assess the frequency of sHLH/MAS in children treated in our institution and to compare the effectiveness of various therapeutic interventions.

MATERIAL AND METHODS

Between 2005 and 2013, 24 children (age: 1-17 years) were consecutively treated for sHLH/MAS. Therapy was based on glucocorticoids (GCs) in high or standard doses (hd-GCs or sd-GCs), intravenous immunoglobulin (IVIG), and cyclosporin A (CyA). A comparison of selected laboratory and clinical parameters during the first 72 h of treatment and after a week from the last intervention applied in the first 72 h after diagnosis was performed retrospectively.

RESULTS

The majority of patients (14/24, 58%) suffered from sHLH/MAS in the course of an autoimmune disease (12 patients diagnosed with a systemic form of juvenile idiopathic arthritis). We found with a confidence level of 95% that the application of hd-GCs in the first 24 h caused rapid alleviation of fever, reduction of hepatosplenomegaly, and an increase in thrombocytes and s-fibrinogen concentrations. The use of combination therapy with hd-GCs, IVIG, and CyA in the first 72 h caused a faster increase in s-fibrinogen. All patients survived and were alive at the follow-up of 1-8 years.

CONCLUSIONS

The results indicate that treatment of sHLH/MAS based on hd-GCs, CyA and IVIG is an effective therapy in children.

Hyperferritinemia and inflammation

Understanding of ferritin biology has traditionally centered on its role in iron storage and homeostasis, with low ferritin levels indicative of deficiency and high levels indicative of primary or secondary hemochromatosis. However, further work has shown that iron, redox biology and inflammation are inexorably linked. During infection, increased ferritin levels represent an important host defense mechanism that deprives bacterial growth of iron and protects immune cell function. It may also be protective, limiting the production of free radicals and mediating immunomodulation. Additionally, hyperferritinemia is a key acute-phase reactants, used by clinicians as an indication for therapeutic intervention, aimed at controlling inflammation in high-risk patients. One school of thought maintains that hyperferritinemia is an 'innocent bystander' biomarker of uncontrolled inflammation that can be used to gauge effectiveness of intervention. Other schools of thought maintain that ferritin induction could be a protective negative regulatory loop. Others maintain that ferritin is a key mediator of immune dysregulation, especially in extreme hyperferritinemia, via direct immune-suppressive and pro-inflammatory effects. There is a clear need for further investigation of the role of ferritin in uncontrolled inflammatory conditions both as a biomarker and mediator of disease because its occurrence identifies patients with high mortality risk and its resolution predicts their improved survival.

Weiss J, Weitzman S, Wouters C, Wulffraat N, Zletni M, Arico M, Egeler RM, Filipovich AH, Gadner H, Imashuku S, Janka G, Ladisch S, McClain KL, Webb D. Development and Initial Validation of the Macrophage Activation Syndrome/Primary Hemophagocytic Lymphohistiocytosis Score, a Diagnostic Tool that Differentiates Primary Hemophagocytic Lymphohistiocytosis from Macrophage Activation Syndrome

OBJECTIVE

To develop and validate a diagnostic score that assists in discriminating primary hemophagocytic lymphohistiocytosis (pHLH) from macrophage activation syndrome (MAS) related to systemic juvenile idiopathic arthritis.

STUDY DESIGN

The clinical, laboratory, and histopathologic features of 362 patients with MAS and 258 patients with pHLH were collected in a multinational collaborative study. Eighty percent of the population was assessed to develop the score and the remaining 20% constituted the validation sample. Variables that entered the best fitted model of logistic regression were assigned a score, based on their statistical weight. The MAS/HLH (MH) score was made up with the individual scores of selected variables. The cutoff in the MH score that discriminated pHLH from MAS best was calculated by means of receiver operating characteristic curve analysis. Score performance was examined in both developmental and validation samples.

RESULTS

Six variables composed the MH score: age at onset, neutrophil count, fibrinogen, splenomegaly, platelet count, and hemoglobin. The MH score ranged from 0 to 123, and its median value was 97 (1st-3rd quartile 75-123) and 12 (1st-3rd quartile 11-34) in pHLH and MAS, respectively. The probability of a diagnosis of pHLH ranged from <1% for a score of <11 to >99% for a score of  ≥123. A cutoff value of ≥60 revealed the best performance in discriminating pHLH from MAS.

CONCLUSION

The MH score is a powerful tool that may aid practitioners to identify patients who are more likely to have pHLH and, thus, could be prioritized for functional and genetic testing.

Macrophage activation syndrome in systemic lupus erythematosus: a multicenter, case-control study in China

The objective of this study was to describe the clinical and laboratory characteristics, precipitating factors, treatment, and outcome of macrophage activation syndrome (MAS) complicating systemic lupus erythematosus (SLE). A multicenter case-control study was performed across six tertiary hospitals from 1997 to 2014. A total of 32 patients with SLE-associated MAS were enrolled. Sixty-four age- and sex-matched SLE patients diagnosed in the same period without MAS episodes were selected as controls. The most frequent clinical feature was fever, followed by splenomegaly. Hyperferritinemia, hypoalbuminemia, and hyper-lactate dehydrogenase (LDH)-nemia were among the most common laboratory abnormalities. Compared with pre-MAS visit, patients at the onset of MAS had greater frequencies of renal involvement, liver dysfunction, and cytopenia. Receiver operating characteristic (ROC) analysis identified optimal cutoff values of ferritin (>662.5 ng/mL) and LDH (>359 U/mL) to predict the occurrence of MAS in SLE. SLE flare and infection were the common triggers of MAS in SLE. Abortion and parturition were recorded as well. The overall mortality rate was 12.5%. All patients received corticosteroids. Cyclosporine A, cyclophosphamide, and etoposide were the three most commonly used immunosuppressants. Rituximab was given to one patient. Intravenous immunoglobulin (IVIG) was added for 46.9% patients. MAS is a potentially fatal complication of SLE. Its occurrence is most frequently associated with active SLE disease or infection. The presentation of unexplained fever, cytopenia, or liver dysfunction, with high levels of ferritin and LDH, in patients with SLE should raise the suspicion of MAS. Corticosteroids with immunosuppressants and IVIG may be an appropriate treatment.

Diagnosing haemophagocytic syndrome

Haemophagocytic syndrome, or haemophagocytic lymphohistiocytosis (HLH), is a hyperinflammatory disorder characterised by uncontrolled activation of the immune system. It can result from mutations in multiple genes involved in cytotoxicity or occur secondary to a range of infections, malignancies or autoimmune rheumatic diseases. In the latter case, it is also known as macrophage activation syndrome (MAS). Characteristic features are persistent fever, hepatosplenomegaly, petechial/purpuric rash, progressive cytopenias, coagulopathy, transaminitis, raised C reactive protein, falling erythrocyte sedimentation rate, hypertriglyceridaemia, hypofibrinogenaemia and extreme hyperferritinaemia often associated with multi-organ impairment. Distinguishing HLH from systemic sepsis can present a major challenge. Criteria for diagnosis and classification of HLH and MAS are available and a serum ferritin >10 000 µg/L is strongly supportive of HLH. Without early recognition and appropriate treatment, HLH is almost universally fatal. However, with prompt referral and advancements in treatment over the past two decades, outcomes have greatly improved.