Macrophage Activation Syndrome: different mechanisms leading to a one clinical syndrome

Treatment intensification in Kawasaki disease - current perspectives

INTRODUCTION

Intravenous immunoglobulin is the standard of care in Kawasaki disease. However, a subset of patients exhibits resistance to intravenous immunoglobulin treatment, even when Kawasaki disease is promptly diagnosed and managed. While intravenous immunoglobulin reduces the occurrence of coronary artery abnormalities from 15-25% to 3-5%, it does not entirely eliminate the risk. Besides, management guidelines for non-coronary complications of Kawasaki disease, for instance, myocarditis, remain speculative.

AREAS COVERED

Recent literature suggests that a subset of patients with Kawasaki disease may benefit from treatment intensification with drugs, such as corticosteroids, infliximab, anakinra, and/or ciclosporin. In this manuscript, we have reviewed recent advances in the management of Kawasaki disease, especially with regard to preemptive intensification of therapy in children at high risk of cardiac complications. A comprehensive search was made using Web of Science, Scopus, and PubMed databases to gather English articles published from 1967 to 2023 on the treatment of Kawasaki disease. We incorporated the following words in the search strategy: 'Kawasaki disease,' 'intravenous immunoglobulin/IVIg,' 'intravenous immunoglobulin/IVIg-resistant Kawasaki disease,' 'treatment intensification,' or 'primary intensification of treatment/therapy.'

EXPERT OPINION

The 'high-risk' group in Kawasaki disease needs to be identified with early intensification of primary therapy for better coronary and myocardial outcomes.

Liver type 1 innate lymphoid cells undergo apoptosis in murine models of macrophage activation syndrome and are dispensable for disease

Macrophage activation syndrome (MAS) exemplifies a severe cytokine storm disorder with liver inflammation. In the liver, classical natural killer (cNK) cells and liver-resident type 1 innate lymphoid cells (ILC1s) dominate the ILC population. Thus far, research has primarily focused on the corresponding role of cNK cells. Considering the liver inflammation and cytokine storm in MAS, liver-resident ILC1s represent an interesting population to explore due to their rapid cytokine production upon environmental triggers. By utilizing a Toll-like receptor (TLR)9- and TLR3:4-triggered MAS model, we showed that ILC1s highly produce IFN-γ and TNF-α. However, activated ILC1s undergo apoptosis and are strongly reduced in numbers, while cNK cells resist inflammation-induced apoptosis. Signs of mitochondrial stress suggest that this ILC1 apoptosis may be driven by inflammation-induced mitochondrial impairment. To study whether early induction of highly cytokine-producing ILC1s influences MAS development, we used Hobit KO mice due to their paucity of liver ILC1s but unaffected cNK cell numbers. Nevertheless, neither the severity of MAS features nor the total inflammatory cytokine levels were affected in these Hobit KO mice, indicating that ILC1s are dispensable for MAS pathogenesis. Collectively, our data demonstrate that ILC1s undergo apoptosis during TLR-triggering and are dispensable for MAS pathogenesis.

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.

CD38high/HLA-DR+CD8+ T lymphocytes display pathogen-specific expansion regardless of hemophagocytic lymphohistiocytosis

The characteristic expansion of T CD38high/HLA-DR+CD8+ lymphocytes observed in hemophagocytic lymphohistiocytosis (HLH) and macrophage activation syndrome (MAS) proved able to distinguish HLH/MAS from sepsis and systemic juvenile idiopathic arthritis. However, the performance of this marker in differentiating HLH/MAS from other pediatric febrile conditions with similar clinical onset and yet entirely different treatments remains unexplored. CD38high/HLA-DR+CD8+ frequencies measured in the peripheral fresh blood of pediatric patients attended for suspicion of HLH/MAS were retrospectively recorded and clinical characteristics were retrieved. CD38high/HLA-DR+CD8+ frequencies in HLH/MAS patients (15 patients; median: 22.0%, IQR: 11.0-49.0%) were compared with those who presented febrile conditions other-than-HLH (28 patients; median: 13.0%, IQR: 3.9-28.7%; p = 0.24). HLH and non-HLH patients were subsequently regrouped based on the presence of an identified infection (22 patients; median: 27.0%, IQR: 15.2-72.1%) and compared with those without infections (21 patients; median: 7.6%, IQR: 3.7-24.3%; p = 0.0035). CD38high/HLA-DR+CD8+ percentages were significantly higher only in the infection group compared with the noninfection one, with a patent pathogen-specific expansion in Epstein-Barr virus primoinfection and visceral leishmaniasis regardless of the presence of HLH. CD38high/HLA-DR+CD8+ frequencies do not appear as an HLH-specific marker as they naturally expand in other clinical situations that are common in childhood and may mimic HLH initial presentation.

New discoveries in the genetics and genomics of systemic juvenile idiopathic arthritis

INTRODUCTION

Systemic juvenile idiopathic arthritis (sJIA) is a severe inflammatory condition with onset in childhood. It is sporadic, but elements of its stereotypical innate immune responses are likely genetically encoded by both common variants with small effect sizes and rare variants with larger effects.

AREAS COVERED

Genomic investigations have defined the unique genetic architecture of sJIA. Identification of the class II HLA locus as the strongest sJIA risk factor for the first time brought attention to T lymphocytes and adaptive immune mechanisms in sJIA. The importance of the human leukocyte antigen (HLA) locus was reinforced by recognition that HLA-DRB1*15 alleles are strongly associated with development of drug reactions and sJIA-associated lung disease (sJIA-LD). At the IL1RN locus, genetic variation relates to both risk of sJIA and may also predict non-response to anakinra. Finally, rare genetic variants may have critical roles in disease complications, such as homozygous LACC1 mutations in families with an sJIA-like illness, and hemophagocytic lymphohistiocytosis (HLH) gene variants in some children with macrophage activation syndrome (MAS).

EXPERT OPINION

Genetic and genomic analysis of sJIA holds great promise for both basic discovery of the course and complications of sJIA, and may help guide personalized medicine and therapeutic decision-making.

Clinical and genetic analysis of macrophage activation syndrome complicating juvenile idiopathic inflammatory myopathies

BACKGROUND

Macrophage activation syndrome (MAS) is a serve complication of juvenile idiopathic inflammatory myopathies (JIIMs). This study delineates the clinical manifestations and genetic underpinnings of JIIM-MAS patients.

METHODS

We retrospectively analysed clinical and UNC13D gene from JIIM patients admitted to our centre between 2011 and 2021 to identify cases of MAS. Additionally, a literature review summarising reported cases of JIIMs and MAS was performed.

RESULTS

Of 773 JIIM patients, 10 (1.3%) were diagnosed with MAS. All patients presented with persistent fever and hyperferritinaemia. Seventy percent of patients met the HLH-2004 criteria, while 90% met the 2016 sJIA-MAS criteria. Most patients received combined treatment of corticosteroids and immunosuppressants. UNC13D gene analysis was performed in six patients. A homozygous pathogenic mutation (c.2588G>A) was detected in one patient with recurrent MAS, and twenty-eight single-nucleotide polymorphisms (SNPs) were detected. Eighty percent of patients exhibiting a consistent combination of ten SNPs compared to JIIM patients without MAS (35%).

CONCLUSION

MAS is an early and often overlooked complication of JIIMs. The 2016 sJIA-MAS criteria may facilitate early diagnosis. Combined corticosteroid and immunosuppressant therapy prove effective. An increased prevalence of UNC13D gene polymorphisms was observed in JIIM-MAS patients, highlighting the necessity for further investigations.

IMPACT

This study aimed to delineate the clinical manifestations and genetic underpinnings of macrophage activation syndrome (MAS) in ten patients with juvenile idiopathic inflammatory myopathies (JIIMs). MAS has been recognised as a complication of JIIMs. However, only a few case reports provide comprehensive descriptions of MAS in JIIM patients, and there are few reports related to UNC13D mutations in these patients. This article offers single-centre clinical insights to enhance the identification and management of MAS in JIIM patients, while also highlighting the potential association between MAS occurrence and UNC13D gene polymorphisms.

Hemophagocytic Lymphohistiocytosis Triggered by Herpes Simplex Virus 1 and 2: A Narrative Review

Introduction: Hemophagocytic lymphohistiocytosis (HLH) is a rare, life-threatening syndrome characterized by an uncontrolled hyperinflammatory reaction. HLH is classified into primary (familial) and secondary (acquired). Secondary HLH is commonly triggered by infections, with viral infections being a leading cause. Its epidemiology and clinical features in cases associated with herpes simplex virus 1 and 2 remain underexplored. This study aimed to review all previously described cases of HSV-1 or -2-triggered HLH and provide information about this syndrome's epidemiology, microbiology, clinical characteristics, treatment, and outcomes. Methods: A narrative review was performed based on a search in PubMed, the Cochrane Library, and Scopus. Studies published until 27 April 2024 providing relevant data for HLH due to HSV 1 and 2 in humans were included. Results: We identified 29 eligible studies reporting HLH due to HSV 1 and 2, involving 34 patients. Half of them were adults, and half were neonates. Fever and splenomegaly were the most common clinical findings. Most patients were diagnosed with HSV-1 (64.7%), with PCR being the primary diagnostic method. The median duration of in-hospital treatment was 21 days, with acyclovir and steroids being the mainstays of therapy. The overall mortality rate was 41.2%, and AST levels emerged as an independent predictor of mortality. Conclusions: Our findings underscore the need for heightened awareness surrounding HLH triggered by HSV 1 and 2 and the importance of prompt diagnosis and tailored treatment approaches.

Immunopathology of and potential therapeutics for secondary hemophagocytic lymphohistiocytosis/macrophage activation syndrome: a translational perspective

Secondary hemophagocytic lymphohistiocytosis/macrophage activation syndrome (sHLH/MAS) is a life-threatening immune disorder triggered by rheumatic disease, infections, malignancies, or medications. Characterized by the presence of hemophagocytic macrophages and a fulminant cytokine storm, sHLH/MAS leads to hyperferritinemia and multiorgan failure and rapidly progresses to death. The high mortality rate and the lack of specific treatments necessitate the development of a new drug. However, the complex and largely unknown immunopathologic mechanisms of sHLH/MAS, which involve dysfunction of various immune cells, diverse etiologies, and different clinical contexts make this effort challenging. This review introduces the terminology, diagnosis, and clinical features of sHLH/MAS. From a translational perspective, this review focuses on the immunopathological mechanisms linked to various etiologies, emphasizing potential drug targets, including key molecules and signaling pathways. We also discuss immunomodulatory biologics, existing drugs under clinical evaluation, and novel therapies in clinical trials. This systematic review aims to provide insights and highlight opportunities for the development of novel sHLH/MAS therapeutics.

Tmem178 Negatively Regulates IL-1β Production Through Inhibition of the NLRP3 Inflammasome

OBJECTIVE

Inflammasomes modulate the release of bioactive interleukin (IL)-1β. Excessive IL-1β levels are detected in patients with systemic juvenile idiopathic arthritis (sJIA) and cytokine storm syndrome (CSS) with mutated and unmutated inflammasome components, raising questions on the mechanisms of IL-1β regulation in these disorders.

METHODS

To investigate how the NLRP3 inflammasome is modulated in sJIA, we focused on Transmembrane protein 178 (Tmem178), a negative regulator of calcium levels in macrophages, and measured IL-1β and caspase-1 activation in wild-type (WT) and Tmem178-/- macrophages after calcium chelators, silencing of Stim1, a component of store-operated calcium entry (SOCE), or by expressing a Tmem178 mutant lacking the Stromal Interaction Molecule 1 (Stim1) binding site. Mitochondrial function in both genotypes was assessed by measuring oxidative respiration, mitochondrial reactive oxygen species (mtROS), and mitochondrial damage. CSS development was analyzed in Perforin-/- /Tmem178-/- mice infected with lymphocytic choriomeningitis virus (LCMV) in which inflammasome or IL-1β signaling was pharmacologically inhibited. Human TMEM178 and IL1B transcripts were analyzed in data sets of whole blood and peripheral blood monocytes from healthy controls and patients with active sJIA.

RESULTS

TMEM178 levels are reduced in whole blood and monocytes from patients with sJIA while IL1B levels are increased. Accordingly, Tmem178-/- macrophages produce elevated IL-1β compared with WT cells. The elevated intracellular calcium levels after SOCE activation in Tmem178-/- macrophages induce mitochondrial damage, release mtROS, and ultimately promote NLRP3 inflammasome activation. In vivo, inhibition of inflammasome or IL-1β neutralization prolongs Tmem178-/- mouse survival in LCMV-induced CSS.

CONCLUSION

Down-regulation of TMEM178 levels may represent a marker of disease activity and help identify patients who could benefit from inflammasome targeting.

From multisystem inflammatory syndrome in children to secondary hemophagocytic lymphohistiocytosis a series of misfortunate events: case report and review of literature

Multisystem inflammatory syndrome of childhood (MIS-C) is a recently described entity in pediatrics post-COVID-19 pandemic. Hemophagocytic lymphohistiocytosis (HLH) is a clinical syndrome caused by an unregulated proliferation of macrophages as well as T lymphocytes. Both entities can be considered overlapping, although distinct criteria for each can be found in the literature. Herein, we report a patient with MIS-C post-COVID-19 infection, complicated with HLH secondary to Plasmodium falciparum malaria from a blood transfusion.

Immunology of Cytokine Storm Syndromes: Natural Killer Cells

Natural killer (NK) cells are innate immune lymphocytes that rapidly produce cytokines upon activation and kill target cells. NK cells have been of particular interest in primary hemophagocytic lymphohistiocytosis (pHLH) since all of the genetic defects associated with this disorder cause diminished cytotoxic capacity of NK cells and T lymphocytes, and assays of NK cell killing are used clinically for the diagnosis of HLH. Herein, we review human NK cell biology and the significance of alterations in NK cell function in the diagnosis and pathogenesis of HLH.

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.

Uncovering the Spectrum of Hemophagocytic Lymphohistiocytosis: A Nephrology Department's Analysis of 14 Cases

Introduction

Hemophagocytic lymphohistiocytosis (HLH) is a disease of multi-organ dysfunction due to excessive immune activation causing widespread inflammation and tissue destruction. It is a severe condition associated with high morbidity and mortality. Early identification is crucial for prompt treatment. The objective of this case series is to underscore the intricacy of managing HLH in individuals with renal dysfunction.

Methods

This is a retrospective study of patients diagnosed with HLH in a nephrology department over a period of 30 years. We retrospectively reviewed the medical files by applying the Revised HLH-2004 criteria.

Results

Among the 14 female patients included, the mean age was 45.2 years (range 23-78). Nine patients presented with sudden onset of fever and chills. Physical examination revealed purpura in 3 cases, hepatomegaly and splenomegaly in 6 and 5 cases respectively, and peripheral lymphadenopathy in 1 case. Hemorrhagic complications were observed in 5 cases, hypertriglyceridemia in 9 cases, and hyperferritinemia in all cases. Hypothyroidism was observed in all cases, and impaired renal function was detected in 11 of them, with 5 experiencing it as a result of lupus nephritis, and 1 case attributed to pre-eclampsia. Hemophagocytosis was confirmed through sternal puncture in 11 cases. Treatment involved etiological therapy with corticosteroids and immunosuppressants and/or anti-infectives. Intravenous immunoglobulins were administered in 6 cases, while 2 cases required coagulation factor transfusions. Unfortunately, 9 patients did not survive.

Conclusion

The study highlights the need for increased awareness and prompt recognition of HLH, particularly in patients with associated renal complications.

Outcome of patients with primary and secondary hemophagocytic lymphohistiocytosis: A retrospective analysis from a tertiary care center

Hemophagocytic lymphohistiocytosis (HLH) is a progressive and potentially life-threatening disorder. It is classified into primary and secondary HLH. The objective of our study was to determine the outcome of primary and secondary HLH in pediatric and adult patients based on HScore and treatment modality. We conducted a retrospective analysis done from July 2010 to June 2020. Variables analyzed included age, gender and history of death in siblings. HScore was used for disease classification while clinical and laboratory findings which were required to fulfill the HScore diagnostic criteria were also recorded. Continuous variables were summarized as median and categorical variables as frequencies and percentages. Categorical variables were compared using chi-square test and Fisher Exact test. Significance of different variables between primary and secondary HLH was calculated using independent-samples t test. A P value of < .05 was taken as significant. A total of 51 patients were included in the analysis (41 in primary and 10 in secondary HLH group). In primary HLH, 36 patients were in the pediatric age group and 12.2% had a history of death in sibling. All 41 patients had increased ferritin and decreased fibrinogen levels. The overall survival in primary HLH was 44%. In the secondary HLH group, viral infections were the most common etiology and ferritin was increased as well. The overall survival in secondary HLH was 60%. The median survival was 15 ± 4.8 months. The overall survival of both groups combined was 53%. Primary HLH should be considered in pediatric patients who present with pancytopenia and hepatosplenomegaly. In centers where genetic testing is not available, HScore along with serum ferritin and fibrinogen is a good substitute for disease classification.

Immune Mechanisms in Inflammatory Anemia

Maintaining the correct number of healthy red blood cells (RBCs) is critical for proper oxygenation of tissues throughout the body. Therefore, RBC homeostasis is a tightly controlled balance between RBC production and RBC clearance, through the processes of erythropoiesis and macrophage hemophagocytosis, respectively. However, during the inflammation associated with infectious, autoimmune, or inflammatory diseases this homeostatic process is often dysregulated, leading to acute or chronic anemia. In each disease setting, multiple mechanisms typically contribute to the development of inflammatory anemia, impinging on both sides of the RBC production and RBC clearance equation. These mechanisms include both direct and indirect effects of inflammatory cytokines and innate sensing. Here, we focus on common innate and adaptive immune mechanisms that contribute to inflammatory anemias using examples from several diseases, including hemophagocytic lymphohistiocytosis/macrophage activation syndrome, severe malarial anemia during Plasmodium infection, and systemic lupus erythematosus, among others.

Tmem178 negatively regulates IL-1β production through inhibition of the NLRP3 inflammasome

Objective

Inflammasomes modulate the release of bioactive IL-1β. Excessive IL-1β levels are detected in patients with systemic juvenile idiopathic arthritis (sJIA) and cytokine storm syndrome (CSS) with mutated and unmutated inflammasome components, raising questions on the mechanisms of IL-1β regulation in these disorders.

Methods

To investigate how the NLRP3 inflammasome is modulated in sJIA, we focused on Tmem178, a negative regulator of calcium levels in macrophages, and measured IL-1β and caspase-1 activation in wild-type (WT) and Tmem178 -/- macrophages following calcium chelators, silencing of Stim1, a component of store-operated calcium entry (SOCE), or by expressing a Tmem178 mutant lacking Stim1 binding site. Mitochondrial function in both genotypes was assessed by measuring oxidative respiration, mitochondrial reactive oxygen species (mtROS), and mitochondrial damage. CSS development was analyzed in Perforin -/- /Tmem178 -/- mice infected with LCMV in which inflammasome or IL-1 signaling was pharmacologically inhibited. Human TMEM178 and IL-1B transcripts were analyzed in a dataset of peripheral blood monocytes from healthy controls and active sJIA patients.

Results

TMEM178 levels are reduced in monocytes from sJIA patients while IL-1B show increased levels. Accordingly, Tmem178 -/- macrophages produce elevated IL-1β compared to WT cells. The elevated intracellular calcium levels following SOCE activation in Tmem178 -/- macrophages induce mitochondrial damage, release mtROS, and ultimately, promote NLRP3 inflammasome activation. In vivo , inhibition of inflammasome or IL-1 neutralization prolongs Tmem178 -/- mouse survival to LCMV-induced CSS.

Conclusion

Downregulation of Tmem178 levels may represent a new biomarker to identify sJIA/CSS patients that could benefit from receiving drugs targeting inflammasome signaling.

Post-COVID-19 syndrome: Insights into a novel post-infectious systemic disorder

Coronavirus disease 2019 (COVID-19) is currently considered a complex systemic infectious and inflammatory disease, determined by the infection with severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2), and the cause of one of the most important epidemiological phenomena in the last century - the COVID-19 pandemic. This infectious-inflammatory disease may generate a wide range of clinical manifestations and biological modifications, explained by the ubiquitous nature of the SARS-CoV-2 receptors, represented by the angiotensin-converting enzyme-2 (ACE-2), and by the host's violent immune and proinflammatory reaction to the viral infection. These manifestations include immunological disturbances, which, according to certain clinical findings, may persist post-infection, in the form of a presumed systemic inflammatory entity, defined by several clinical concepts with a common pathological significance: post-COVID-19 multisystem (or systemic) inflammatory syndrome, post-COVID syndrome or long-COVID. Although the pathophysiological mechanisms of the post-COVID-19 syndrome are elusive at the present moment, there are currently several studies that describe a systemic inflammatory or autoimmune phenomenon following the remission of the COVID-19 infection in some patients, which suggests the existence of molecular and cellular immune abnormalities, most probably due to the host's initial violent immune response to the viral infection, in the form of three overlapping entities: secondary hemophagocytic lymph histiocytosis (HLH), macrophage activation syndrome (MAS) and cytokine release syndrome (CRS). Thus, this is reminiscent of different classic autoimmune diseases, in which various infections are risk factors in developing the autoimmune process.

Platelet and ferritin as early predictive factors for the development of macrophage activation syndrome in children with Kawasaki disease: A retrospective case-control study

OBJECTIVE

To investigate the early predictive factors for Kawasaki disease complicated with macrophage activation syndrome (KD-MAS).

METHODS

We performed a retrospective case-control study in children with KD from August 2017 to August 2022, involving 28 cases with KD-MAS and 112 cases not developing KD-MAS. Based on the univariate analysis, binary logistic regression was used to identify the early predictive factors for KD-MAS development, and the receiver operating characteristic curve (ROC) analysis was carried out to obtain the optimal cut-off value.

RESULTS

Two predictive factors were associated with the development of KD-MAS, which were PLT (OR = 1.013, 95%CI, 1.001-1.026), and serum ferritin (OR = 0.991, 95%CI, 0.982-0.999). The cut-off value of PLT was 110 × 10⁹/L, and the cut-off value of serum ferritin was 548.4 ng/ml.

CONCLUSION

Children with KD who had a PLT count under 110 × 10⁹/L, and a serum ferritin level over 548.4 ng/ml are more likely to develop KD-MAS.

The Role of Immune Mechanisms, Inflammatory Pathways, and Macrophage Activation Syndrome in the Pathogenesis of Hemophagocytic Lymphohistiocytosis

This review article describes the pathophysiology of hemophagocytic lymphohistiocytosis (HLH). The condition is characterized by excessive stimulation of inflammatory cytokines, lymphocytes, and macrophages, leading to hyperinflammatory disorder with immune dysfunction. The main clinical and diagnostic features include fever ≥38.5°C, splenomegaly, hyperferritinemia, cytopenia, hypofibrinogenemia, hemophagocytosis on the bone marrow, low or absent of natural killer (NK) cell activity, and elevated soluble CD25. Various immunological and inflammatory mechanisms are involved in the pathogenesis of HLH. Moreover, the condition can result in multisystem organ failure, contributing to the high mortality rate in hospital settings. A thorough literature search was conducted by collecting data from multiple articles published on PubMed, Medline, and Google Scholar. The article discusses the cellular and molecular pathways that lead to HLH. Due to the high rate of morbidity and mortality, early diagnosis needs to be established. More research pertaining to molecular biology, immunology, and the genetics of HLH is needed to explore the effective management and treatment of this rare disorder.

Variation of Diagnostic Approaches and Treatment Practices for Hemophagocytic Lymphohistiocytosis/Macrophage Activation Syndrome Among Pediatric Subspecialists

OBJECTIVE

To assess the diagnostic and treatment practices among a variety of subspecialists at pediatric institutions in the US.

STUDY DESIGN

Using a web-based survey, we assessed the consultation, diagnostic, and treatment preferences of providers from the different pediatric subspecialties who care for pediatric patients with hemophagocytic lymphohistiocytosis (HLH)/macrophage activating syndrome (MAS). Domains included demographics, provider training level and specialty, experience and comfort level with the diagnosis and treatment of HLH/MAS, and institutional approaches toward the diagnosis and management of HLH/MAS. Participants also were given 2 case scenarios: one describing Epstein-Barr virus-associated HLH and another describing an underlying rheumatologic condition with MAS.

RESULTS

Of 263 respondents, 23%, 29%, 39%, and 7% identified as hematology/oncology, rheumatology, general pediatrics/critical care/hospitalist, and allergy/immunology, respectively. For Epstein-Barr virus/HLH, hematology/oncology was the preferred first consultant by most respondents other than rheumatologists, of whom only 47% agreed. For MAS, 92% of respondents from all specialties favored a rheumatology consultation. Preferred diagnostic tests varied by subspecialty, with hematology/oncology more likely than rheumatology to order an infectious workup, natural killer cell function, soluble interleukin-2 receptor, bone marrow biopsy, and genetic testing. First-line therapy also varied, with hematology/oncology preferring dexamethasone and etoposide and rheumatology more often preferring methylprednisolone and anakinra. One-half of respondents were unaware of institutional algorithms for diagnosis and treatment of HLH/MAS. Most (85.6%) favored the development of treatment algorithms for HLH/MAS, and 90% supported a multidisciplinary approach.

CONCLUSIONS

Current consulting patterns, diagnostic workup, and treatment approaches of HLH/MAS vary by specialty, highlighting the need for standardized management algorithms and institutional multidisciplinary HLH/MAS teams.

Progress, pitfalls, and path forward of drug repurposing for COVID-19 treatment

On 30 January 2020, the World Health Organization (WHO) declared the novel severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) epidemic a public health emergency of international concern. The viral outbreak led in turn to an exponential growth of coronavirus disease 2019 (COVID-19) cases, that is, a multiorgan disease that has led to more than 6.3 million deaths worldwide, as of June 2022. There are currently few effective drugs approved for treatment of SARS-CoV-2/COVID-19 patients. Many of the compounds tested so far have been selected through a drug repurposing approach, that is, by identifying novel indications for drugs already approved for other conditions. We here present an up-to-date review of the main Food and Drug Administration (FDA)-approved drugs repurposed against SARS-CoV-2 infection, discussing their mechanism of action and their most important preclinical and clinical results. Reviewed compounds were chosen to privilege those that have been approved for use in SARS-CoV-2 patients or that have completed phase III clinical trials. Moreover, we also summarize the evidence on some novel and promising repurposed drugs in the pipeline. Finally, we discuss the current stage and possible steps toward the development of broadly effective drug combinations to suppress the onset or progression of COVID-19.

Point-of-care contrast enhanced lung ultrasound and COVID-19

OBJECTIVES

Bedside lung ultrasound has been indispensable during the coronavirus disease 2019 (COVID-19) pandemic, allowing us to rapidly assess critically unwell patients. We demonstrate the unique application of contrast-enhanced ultrasound with the aim of further understanding this disease.

METHODS

Patient demographics were recorded alongside recent cross-sectional imaging and inflammatory markers. Ultrasound was conducted by experienced operators in a portable setting. Conventional six-point lung ultrasound method was used to evaluate B-lines, small (subpleural) consolidation and the pleura. Areas of small consolidation were targeted after intravenous administration of ultrasound contrast.

RESULTS

The areas of small consolidations, a potential sign of pneumonia on B-mode lung ultrasound, usually enhance on contrast-enhanced ultrasound. Our study revealed these areas to be avascular, indicating an underlying thrombotic/infarction process. Findings were present in 100% of the patients we examined. We have also shown that the degree of infarction correlates with CT severity (r = 0.4) and inflammatory markers, and that these areas improve as patients recover.

CONCLUSIONS

We confirmed the theory of immune thrombus by identifying the presence of microthrombi in the lungs of 100% of our patients, despite 79% having had a recent negative CT pulmonary angiogram study. contrast-enhanced ultrasound can be utilised to add confidence to an uncertain COVID-19 diagnosis and for prognosticating and monitoring progress in confirmed COVID-19 patients. Contrast-enhanced ultrasound is clearly very different to CT, the gold standard, and while there are specific pathologies that can only be detected on CT, contrast-enhanced ultrasound has many advantages, most notability the ability to pick up microthrombi at the periphery of the lungs.

Inflammasomes—New Contributors to Blood Diseases

Inflammasomes are intracellular multimeric complexes that cleave the precursors of the IL-1 family of cytokines and various proteins, found predominantly in cells of hematopoietic origin. They consist of pattern-recognition receptors, adaptor domains, and the enzymatic caspase-1 domain. Inflammasomes become activated upon stimulation by various exogenous and endogenous agents, subsequently promoting and enhancing inflammatory responses. To date, their function has been associated with numerous pathologies. Most recently, many studies have focused on inflammasomes’ contribution to hematological diseases. Due to aberrant expression levels, NLRP3, NLRP1, and NLRC4 inflammasomes were indicated as predominantly involved. The NLRP3 inflammasome correlated with the pathogenesis of non-Hodgkin lymphomas, multiple myeloma, acute myeloid leukemia, lymphoid leukemias, myelodysplastic neoplasms, graft-versus-host-disease, and sickle cell anemia. The NLRP1 inflammasome was associated with myeloma and chronic myeloid leukemia, whereas NLRC4 was associated with hemophagocytic lymphohistiocytosis. Moreover, specific gene variants of the inflammasomes were linked to disease susceptibility. Despite the incomplete understanding of these correlations and the lack of definite conclusions regarding the therapeutic utility of inflammasome inhibitors, the available results provide a valuable basis for clinical applications and precede upcoming breakthroughs in the field of innovative treatments. This review summarizes the latest knowledge on inflammasomes in hematological diseases, indicates the potential limitations of the current research approaches, and presents future perspectives.

Spontaneous NLRP3 inflammasome-driven IL1-β secretion is induced in severe COVID-19 patients and responds to anakinra treatment

BACKGROUND

SARS-CoV-2 infection may result in a severe pneumonia associated to elevation of blood inflammatory parameters, reminiscent of cytokine storm syndrome. Steroidal anti-inflammatory therapies have shown efficacy in reducing mortality in critically ill patients, however the mechanisms by which SARS-CoV2 virus triggers such an extensive inflammation remain unexplained.

OBJECTIVES

To dissect the mechanisms underlying SARS-CoV-2 associated inflammation in severe COVID-19 patients we studied the role of IL-1β, a pivotal cytokine driving inflammatory phenotypes, whose maturation and secretion are regulated by inflammasomes.

METHODS

We analyzed NLRP3 pathway activation by means of confocal microscopy, plasma cytokine measurement, cytokine secretion following in vitro stimulation of blood circulating monocytes and whole blood RNA sequencing. The role of ORF3a SARS-CoV2 protein was assessed by confocal microscopy analysis following nucleofection of a monocytic cell line.

RESULTS

We found that circulating monocytes from COVID-19 patients display ASC specks that colocalize with NLRP3 inflammasome and spontaneously secrete IL-1β in vitro. This spontaneous activation reverts following patient's treatment with the IL-1 receptor antagonist anakinra. Transfection of a monocytic cell line with cDNA coding for the ORF3a SARS-CoV2 protein, resulted in ASC speck formation CONCLUSIONS: These results provide further evidence that IL-1β targeting could represent an effective strategy in this disease and suggest a mechanistic explanation for the strong inflammatory manifestations associated to COVID-19.

Secondary haemophagocytic lymphohistiocytosis in COVID-19: correlation of the autopsy findings of bone marrow haemophagocytosis with HScore

BACKGROUND

Secondary haemophagocytic lymphohistiocytosis (sHLH) is characterised by a hyper activation of immune system that leads to multiorgan failure. It is suggested that excessive immune response in patients with COVID-19 could mimic this syndrome. Some COVID-19 autopsy studies have revealed the presence of haemophagocytosis images in bone marrow, raising the possibility, along with HScore parameters, of sHLH.

AIM

Our objective is to ascertain the existence of sHLH in some patients with severe COVID-19.

METHODS

We report the autopsy histological findings of 16 patients with COVID-19, focusing on the presence of haemophagocytosis in bone marrow, obtained from rib squeeze and integrating these findings with HScore parameters. CD68 immunohistochemical stains were used to highlight histiocytes and haemophagocytic cells. Clinical evolution and laboratory parameters of patients were collected from electronic clinical records.

RESULTS

Eleven patients (68.7%) displayed moderate histiocytic hyperplasia with haemophagocytosis (HHH) in bone marrow, three patients (18.7%) displayed severe HHH and the remainder were mild. All HScore parameters were collected in 10 patients (62.5%). Among the patients in which all parameters were evaluable, eight patients (80%) had an HScore >169. sHLH was not clinically suspected in any case.

CONCLUSIONS

Our results support the recommendation of some authors to use the HScore in patients with severe COVID-19 in order to identify those who could benefit from immunosuppressive therapies. The presence of haemophagocytosis in bone marrow tissue, despite not being a specific finding, has proved to be a very useful tool in our study to identify these patients.

Short-term, low-dose etoposide in refractory adult-onset Still's disease-associated macrophage activation syndrome

INTRODUCTION

In this study, we modified the classical regimen of the hemophagocytic lymphohistiocytosis-04 protocol and evaluated the efficacy and safety of short-term, low-dose etoposide in patients with refractory macrophage activation syndrome (MAS) associated with adult-onset Still's disease (AOSD).

METHODS

A total of 17 patients with refractory AOSD-associated MAS were enrolled and received short-term, low-dose etoposide (100 mg twice a week for four times). Another 11 patients, who were not treated with etoposide, were included as historical controls. Patient information, such as clinical manifestations, laboratory results, treatments, and short-term prognosis, were recorded and analyzed.

RESULTS

In this case series, 88.24% of the patients with MAS who were treated with short-term, low-dose etoposide had a favorable response in 3 weeks, which was significantly higher (p = 0.017) than that in the patients with MAS who were treated without etoposide (45.45%). The 90-day survival rate after the onset of MAS was significantly higher (p = 0.0029) among the patients in the short-term etoposide group (16/17, 94.12%) than in the control group (5/11, 45.45%).

CONCLUSION

The regimen of short-term (2 weeks), low-dose etoposide was highly effective in the treatment for patients with refractory AOSD-associated MAS with an acceptable safety profile. Key Points • There is no high level evidence to guide the management of refractory MAS-associated AOSD patients. • This study was the first to propose and confirm the efficacy and safety of short-term, low-dose etoposide in the treatment of refractory MAS-associated AOSD patients.

Efficacy of Anakinra on Multiple Coronary Arteries Aneurysms in an Infant with Recurrent Kawasaki Disease, Complicated by Macrophage Activation Syndrome

Kawasaki disease (KD) is rare in infants less than 3 months of age, and its recurrence is exceptional. Infants with KD are at higher risk of severe clinical presentation, therapy failure, complications and coronary aneurysms (CAAs), and this is the reason they deserve more aggressive therapy and a strict clinical follow-up. We report a 2-month-old male with KD, complicated by Macrophage Activation Syndrome (MAS). Despite timely and aggressive therapy with immunoglobulins, steroids and aspirin, multiple CAAs developed. Two-month therapy with anakinra completely reverted all the aneurysms. After six months, the infant experienced KD relapse and was successfully re-treated with immunoglobulins, steroids and aspirin. A strict echocardiographic follow-up did not show recurrence of aneurysms. Two years later, the child is healthy, without cardiac sequelae. In our experience, anakinra was effective in reverting multiple aneurysms and its effect proved to be long-lasting, even in front of KD recurrence. Based on this evidence, it seems reasonable to hypothesize not to limit the use of anakinra as rescue therapy for complicated or refractory KD, but to consider the possibility of adding it to first-line therapies for some subgroups of very-high-risk patients, in order to strengthen the prevention of CAAs.

Implications of SARS-CoV-2 Infection in Systemic Juvenile Idiopathic Arthritis

Systemic juvenile idiopathic arthritis (sJIA) is a serious multifactorial autoinflammatory disease with a significant mortality rate due to macrophage activation syndrome (MAS). Recent research has deepened the knowledge about the pathophysiological mechanisms of sJIA-MAS, facilitating new targeted treatments, and biological disease-modifying antirheumatic drugs (bDMARDs), which significantly changed the course of the disease and prognosis. This review highlights that children are less likely to suffer severe COVID-19 infection, but at approximately 2–4 weeks, some cases of multisystem inflammatory syndrome in children (MIS-C) have been reported, with a fulminant course. Previous established treatments for cytokine storm syndrome (CSS) have guided COVID-19 therapeutics. sJIA-MAS is different from severe cases of COVID-19, a unique immune process in which a huge release of cytokines will especially flood the lungs. In this context, MIS-C should be reinterpreted as a special MAS, and long-term protection against SARS-CoV-2 infection can only be provided by the vaccine, but we do not yet have sufficient data. COVID-19 does not appear to have a substantial impact on rheumatic and musculoskeletal diseases (RMDs) activity in children treated with bDMARDs, but the clinical features, severity and outcome in these patients under various drugs are not yet easy to predict. Multicenter randomized controlled trials are still needed to determine when and by what means immunoregulatory products should be administered to patients with sJIA-MAS with a negative corticosteroid response or contraindications, to optimize their health and safety in the COVID era.

Role of Distinct Macrophage Populations in the Development of Heart Failure in Macrophage Activation Syndrome

Macrophage activation syndrome (MAS) is one of the few entities in rheumatology with the potential to quickly cause multiple organ failure and loss of life, and as such, requires urgent clinical intervention. It has a broad symptomatology, depending on the organs it affects. One especially dangerous aspect of MAS's course of illness is myocarditis leading to acute heart failure and possibly death. Research in recent years has proved that macrophages settled in different organs are not a homogenous group, with particular populations differing in both structure and function. Within the heart, we can determine two major groups, based on the presence of the C-C 2 chemokine receptor (CCR2): CCR2+ and CCR2-. There are a number of studies describing their function and the changes in the population makeup between normal conditions and different illnesses; however, to our knowledge, there has not been one touching on the matter of changes occurring in the populations of heart macrophages during MAS and their possible consequences. This review summarizes the most recent knowledge on heart macrophages, the influence of select cytokines (those particularly significant in the development of MAS) on their activity, and both the immediate and long-term consequences of changes in the makeup of specific macrophage populations-especially the loss of CCR2- cells that are responsible for regenerative processes, as well as the substitution of tissue macrophages by the highly proinflammatory CCR2+ macrophages originating from circulating monocytes. Understanding the significance of these processes may lead to new discoveries that could improve the therapeutic methods in the treatment of MAS.

Macrophage Polarization and Plasticity in Systemic Lupus Erythematosus

Systemic lupus erythematosus (SLE) is an autoimmune disease that attacks almost every organ. The condition mostly happens to adults but is also found in children, and the latter have the most severe manifestations. Among adults, females, especially non-Caucasian, are mostly affected. Even if the etiology of SLE remains unclear, studies show a close relation between this disease and both genetics and environment. Despite the large number of published articles about SLE, we still do not have a clear picture of its pathogenesis, and no specific drug has been found to treat this condition effectively. The implication of macrophages in SLE development is gaining ground, and studying it could answer these gaps. Indeed, both in vivo and in vitro studies increasingly report a strong link between this disease and macrophages. Hence, this review aims to explore the role of macrophages polarization and plasticity in SLE development. Understanding this role is of paramount importance because in-depth knowledge of the connection between macrophages and this systemic disease could clarify its pathogenesis and provide a foundation for macrophage-centered therapeutic approaches.

The spectrum of hemophagocytic lymphohistiocytosis: a retrospective study comparing adult macrophage activation syndrome to malignancy-associated hemophagocytic lymphohistiocytosis

Secondary hemophagocytic lymphohistiocytosis (sHLH) is a life-threatening inflammatory syndrome that can be triggered by autoimmune diseases, malignancy, or infection. In rheumatologic patients, sHLH is referred to as macrophage activation syndrome (MAS). Differentiating between triggers is important for prompt treatment and prognosis. Data comparing subsets of sHLH are limited due to the rarity of this disease. We aim to explore differences in clinical features that may differentiate MAS from malignancy-associated HLH (mHLH) patients. We conducted a single-center retrospective study assessing clinical characteristics, laboratory parameters, treatment regimens and outcomes in 34 patients with sHLH over a 16 year period. We compared patients with MAS to those with mHLH. Hepatomegaly was not present in the MAS group but was present in the mHLH group (0 vs. 25%, p = 0.024). MAS patients had on average nearly double the concentration of platelets at 50.0 (IQR: 31.0–78.0 Kµ/L) vs. 29.0 Kµ/L (IQR: 14.0–37.5 Kµ/L), p = 0.003. Soluble IL-2R concentrations were four times lower in the MAS group with a median soluble IL-2R concentration of 6814.5 kU/L (IQR: 2101–2610 kU/L) vs. 27972.0 kU/L (IQR: 12,820–151,650 kU/L), p = 0.010. The MAS group fared better overall than the mHLH group but was not statistically significant (mortality 22 vs. 44%, p = 0.18). MAS and mHLH patients exhibited different laboratory parameters and clinical features, most notably differences in platelet counts, soluble IL-2R concentration and hepatomegaly, which may help differentiate these conditions early in their course.

Exosome miR-155-5p Derived from Lung Cancer Hcc827 Promotes Macrophage Activation and Lung Cancer Progression

This stud intends to assess whether exosome miR-155-5p derived from human non-small cell lung cancer cells (Hcc827) activates macrophages in lung cancer. Lung cancer Hcc827 cells were assigned into control group and expeirmental group (cultured with macrophages, THP-1 activated by exosome miR-155-5P derived from Hcc827) followed by analysis of macrophage markers inducible nitric oxide synthase (INOS), recombinant human CD163 (CD163), matrix metallopeptidase 9 (MMP9), matrix metallopeptidase 2 (MMP2), and E-cadherin by real-time fluorescent quantitative PCR (RFQ-PCR), IL-10, IL-6 and IL-8 levels by chemiluminescence, cell invasion by Transwell assay and related protein expression by Western blot. miR-155-5p treatment significantly reduced INOS and TNF-β expressions and increased CD163, TNF-α, IL-8, IL-6 and IL-10 expressions along with enhanced cell invasion. In addition, MMP9 and MMP2 expressions in experimental group were significantly increased and E-cdherin was reduced. In conclusion, exosome miR-155-5p derived from lung cancer Hcc827 cells activates macrophages and enhanced lung cancer cell invasion.

Macrophage Activation Led Acute Heart Failure Managed Successfully with Immunosuppression

Macrophage activation leading to multi-organ dysfunction/failure has been described in various hematologic disorders like hemophagocytic lympho-histiocytosis (HLH), also known as macrophage activation syndrome (MAS) and macrophage activation like syndrome (MALS). Congestive heart failure (CHF) appears to be an uncommon manifestation of macrophage activation. This novel entity of macrophage activation-associated cytokine-mediated CHF has not been well reported in the medical literature. We report two young female patients with acute CHF secondary to macrophage activation-associated cytokine storm. An extensive diagnostic workup was negative for other etiologies, such as ischemia, myocarditis, or infections. Their clinical, laboratory, and pathologic findings did not meet the diagnostic criteria for hemophagocytic syndrome (HPS)/MAS. However, both had laboratory and pathologic findings which were consistent with macrophage activation and cytokine storm. One patient met criteria for MALS. Therapeutically, our patients were promptly treated with steroids with or without anti-cytokine therapy with rapid restoration of cardiac function. Macrophage activation-induced disease may not always fulfil the diagnostic criteria for the currently known macrophage activation disorders. We suggest that markers of macrophage activation and cytokine levels should be part of the diagnostic workup in patients with otherwise unexplained acute CHF. Additional research is warranted to further elucidate the underlying mechanism of this disorder.

Cytokine-induced liver injury in coronavirus disease-2019 (COVID-19): untangling the knots

Liver dysfunction manifesting as elevated aminotransferase levels has been a common feature of coronavirus disease-2019 (COVID-19) infection. The mechanism of liver injury in COVID-19 infection is unclear. However, it has been hypothesized to be a result of direct cytopathic effects of the virus, immune dysfunction and cytokine storm-related multiorgan damage, hypoxia-reperfusion injury and idiosyncratic drug-induced liver injury due to medications used in the management of COVID-19. The favored hypothesis regarding the pathophysiology of liver injury in the setting of COVID-19 is cytokine storm, an aberrant and unabated inflammatory response leading to hyperproduction of cytokines. In the current review, we have summarized the potential pathophysiologic mechanisms of cytokine-induced liver injury based on the reported literature.

Targeting interferon-γ in hyperinflammation: opportunities and challenges

Interferon-γ (IFNγ) is a pleiotropic cytokine with multiple effects on the inflammatory response and on innate and adaptive immunity. Overproduction of IFNγ underlies several, potentially fatal, hyperinflammatory or immune-mediated diseases. Several data from animal models and/or from translational research in patients point to a role of IFNγ in hyperinflammatory diseases, such as primary haemophagocytic lymphohistiocytosis, various forms of secondary haemophagocytic lymphohistiocytosis, including macrophage activation syndrome, and cytokine release syndrome, all of which are often managed by rheumatologists or in consultation with rheumatologists. Given the effects of IFNγ on B cells and T follicular helper cells, a role for IFNγ in systemic lupus erythematosus pathogenesis is emerging. To improve our understanding of the role of IFNγ in human disease, IFNγ-related biomarkers that are relevant for the management of hyperinflammatory diseases are progressively being identified and studied, especially because circulating levels of IFNγ do not always reflect its overproduction in tissue. These biomarkers include STAT1 (specifically the phosphorylated form), neopterin and the chemokine CXCL9. IFNγ-neutralizing agents have shown efficacy in the treatment of primary haemophagocytic lymphohistiocytosis in clinical trials and initial promising results have been obtained in various forms of secondary haemophagocytic lymphohistiocytosis, including macrophage activation syndrome. In clinical practice, there is a growing body of evidence supporting the usefulness of circulating CXCL9 levels as a biomarker reflecting IFNγ production.

Regulation of myeloid-cell activation

Myeloid cells (macrophages, monocytes, dendritic cells, and granulocytes) survey the body for signs of infection and damage and regulate tissue homeostasis, organogenesis, and immunity. They express receptors that initiate the inflammatory response, send signals that alter the vascular and cytokine milieu, and oversee the recruitment, differentiation, and activation of other myeloid and adaptive immune cells. Their activation must therefore be tightly regulated, optimized for maximal innate-immune protection with a minimum of collateral tissue damage or disorganization. In this review we discuss what it means for myeloid cells to become activated, with emphasis on the receptors and signaling molecules important for the recognition of pathogen-associated and damage-associated molecular patterns. We also outline how these signals are regulated by the steric properties of proteins, by adhesive and cytoskeletal interactions, and by negative feedback to keep inflammation in check and support healthy tissue development and homeostasis. Throughout the text we highlight recent publications and reviews and direct readers therein for a comprehensive bibliography.

An Economic Comparison of Treatment Strategies with Anakinra in Systemic Juvenile Idiopathic Arthritis (sJIA)

Introduction

Systemic juvenile idiopathic arthritis (sJIA) is a rare, complex autoinflammatory disease with substantial morbidity, often characterized by fever, rash, and muscle pain, amongst other symptoms. Biologic agents, such as anakinra, have been successfully used to treat patients internationally, but their usage in some regions is limited to patients that have failed to achieve clinically inactive disease with corticosteroids and conventional synthetic disease-modifying anti-rheumatic drugs (csDMARDs). Use of anakinra early in the disease course leads to better clinical outcomes; however, longer-term costs for this treatment strategy have not been established. This study compares the economic implications of first-line versus later-line availability of anakinra for patients with sJIA.

Methods

Data for patients treated with first-line anakinra were identified from a single-center, prospective study and compared to a combination of published trial and economic evaluation information to facilitate a comparison to later-line anakinra (ie, following corticosteroids + csDMARDs). Costs were estimated for product acquisition and medical resource utilization (MRU), including planned outpatient visits and unplanned hospital admissions. Total costs over a 5-year horizon were compared.

Results

Total 5-year product acquisition cost for the first-line anakinra strategy was €24,021, and for later-line anakinra was €20,471. The corresponding MRU costs were €19,197 (first-line) versus €25,425 (later-line). Overall 5-year costs (product acquisition and MRU) were lower for the first-line strategy (€43,218 versus €45,896).

Conclusion

The use of anakinra for patients with sJIA in the first-line setting is efficacious to induce and sustain inactive disease, and the findings of this study show that this treatment strategy leads to cost savings through reduced medical expenditure.

Association of HScore Parameters with Severe COVID-19: A Systematic Review and Meta-Analysis

BACKGROUND

Several reports have associated the severe Coronavirus disease-2019 (sCOVID-19) with secondary-hemophagocytic lymphohistiocytosis (sHLH) and proposed utilizing the hemophagocytic syndrome diagnostic score (HScore) for sCOVID-19 patients. We conducted a systematic review and meta-analysis to find the possible association of HScore parameters with severity in COVID-19 patients.

METHODS

A systematic search was performed in Medline via PubMed, EMBASE, and Cochrane databases using all HScore and COVID-19 keywords. The studies were all from 2020, and the study language was limited to English. The records were screened based on inclusion/exclusion criteria. Random/fixed-effect models were employed for meta-analysis, based on the I2 index of parameters. The pooled mean differences were estimated for continuous parameters. The pooled odds-ratio was estimated for fever. The level of significance was set at 0.05.

RESULTS

Eighteen studies (comprising 2459 patients) out of 26151 screened studies were included in this meta-analysis. The results showed that the level of leukocyte, neutrophil, aspartate transaminase (AST), ferritin, and fibrinogen were significantly higher in sCOVID-19 patients than in non-severe ones. Significant lower levels of lymphocyte, platelet, and hemoglobin were also found in sCOVID-19 patients than non-severe patients. Fever was nearly associated with two times increased odds of sCOVID-19 (P=0.051).

CONCLUSION

Lymphopenia, thrombocytopenia, hypohemoglobinemia, hyperferritinemia, high levels of AST, and fever are common features of both sCOVID-19 and HLH. However, the leukocytosis, neutrophilia, and hyperfibrinogenemia found in sCOVID-19 are in contrast with HScore. Conclusively, HScore parameters could be risk factors for sCOVID-19. However, some parameters' roles are contradictory, suggesting the need for further investigation and a new way of HScore interpretation in sCOVID-19 patients.A preprint of this study was published at https://www.researchsquare.com/article/rs-54490/v2.

BTK inhibitors for severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2): A systematic review

Introduction

The Bruton tyrosine kinase (BTK) regulates B cell and macrophage signaling, development, survival, and activation. Inhibiting BTK has been hypothesized to ameliorate lung injury in patients with severe COVID-19, however clinical outcome data is inconclusive.

Objective

To evaluate the clinical outcomes of BTK inhibitors (BTKinibs) in patients with COVID-19.

Evidence review

We searched PubMed, Embase, and Web of Science:Core on December 30, 2020. Clinical studies with at least 5 COVID-19 patients treated with BTKinibs were included. Case reports and reviews were excluded.

Findings

125 articles were identified, 6 of which met inclusion criteria. The most common clinical outcomes measured were oxygen requirements (4/6) and hospitalization rate or duration (3/6). Three studies showed decreased oxygen requirements in patients who started or continued BTKinibs. All three studies that evaluated hospitalization rate or duration found favorable outcomes in those on BTKinibs.

Conclusions and relevance

BTKinib use was associated with decreased oxygen requirements and decreased hospitalization rates and duration.

The cytokine storms of COVID-19, H1N1 influenza, CRS and MAS compared. Can one sized treatment fit all?

An analysis of published data appertaining to the cytokine storms of COVID-19, H1N1 influenza, cytokine release syndrome (CRS), and macrophage activation syndrome (MAS) reveals many common immunological and biochemical abnormalities. These include evidence of a hyperactive coagulation system with elevated D-dimer and ferritin levels, disseminated intravascular coagulopathy (DIC) and microthrombi coupled with an activated and highly permeable vascular endothelium. Common immune abnormalities include progressive hypercytokinemia with elevated levels of TNF-α, interleukin (IL)-6, and IL-1β, proinflammatory chemokines, activated macrophages and increased levels of nuclear factor kappa beta (NFκB). Inflammasome activation and release of damage associated molecular patterns (DAMPs) is common to COVID-19, H1N1, and MAS but does not appear to be a feature of CRS. Elevated levels of IL-18 are detected in patients with COVID-19 and MAS but have not been reported in patients with H1N1 influenza and CRS. Elevated interferon-γ is common to H1N1, MAS, and CRS but levels of this molecule appear to be depressed in patients with COVID-19. CD4+ T, CD8+ and NK lymphocytes are involved in the pathophysiology of CRS, MAS, and possibly H1N1 but are reduced in number and dysfunctional in COVID-19. Additional elements underpinning the pathophysiology of cytokine storms include Inflammasome activity and DAMPs. Treatment with anakinra may theoretically offer an avenue to positively manipulate the range of biochemical and immune abnormalities reported in COVID-19 and thought to underpin the pathophysiology of cytokine storms beyond those manipulated via the use of, canakinumab, Jak inhibitors or tocilizumab. Thus, despite the relative success of tocilizumab in reducing mortality in COVID-19 patients already on dexamethasone and promising results with Baricitinib, the combination of anakinra in combination with dexamethasone offers the theoretical prospect of further improvements in patient survival. However, there is currently an absence of trial of evidence in favour or contravening this proposition. Accordingly, a large well powered blinded prospective randomised controlled trial (RCT) to test this hypothesis is recommended.

Hide and seek in a pandemic: review of SARS-CoV-2 infection and sequelae in children

New Findings

What is the topic of this review?

A description of the current literature relating to COVID‐19 infection in children and the associated inflammatory condition, paediatric multi‐inflammatory syndrome temporally associated with SARS‐CoV‐2 (PIMS‐TS).

What advances does it highlight?

Children with SARS‐CoV‐2 infection have a distinct clinical phenotype when compared to adults. This may relate to relative differences in their adaptive immunity and in the degree and distribution of expression of the SARS‐CoV‐2 receptor (angiotensin‐converting enzyme 2). There are several similarities between PIMS‐TS, Kawasaki disease shock syndrome and other known inflammatory disorders such as macrophage activation syndrome. Few data are available to date regarding vaccination responses of children against COVID‐19.

Abstract

Children infected with SARS‐CoV‐2 have a clinical phenotype that is distinct from that observed in adult cases. They can present with a range of respiratory, gastrointestinal and neurological symptoms, or with a delayed hyperinflammatory syndrome (paediatric multisystem inflammatory system temporally associated with SARS‐CoV‐2; PIMS‐TS) that frequently requires treatment in an intensive care unit. These manifestations may be related to unique expression of transmembrane receptors and immune physiology in children. The clinical features and inflammatory profile of PIMS‐TS are similar to other inflammatory disorders that occur in children such as Kawasaki disease, macrophage activation syndrome and sepsis. Given children are infected less frequently and have less severe disease due to COVID‐19 compared to adults, their physiological profile is of great interest. An understanding of the unique mechanisms of infection and disease in children could aid the identification of potential therapeutic targets. Like adults, children can have long‐term complications of SARS‐CoV‐2 infection, including neurological and cardiac morbidity. Vaccination against SARS‐CoV‐2 is not yet authorised in children aged <12 years, and hence we anticipate ongoing paediatric presentations of COVID‐19 in the coming months.

Macrophage activation syndrome: A diagnostic challenge (Review)

Macrophage activation syndrome (MAS) represents an acute and severe inflammatory syndrome, idiopathic (primary) or secondary to infections, rheumatic diseases, malignancies, or drugs. MAS is underdiagnosed, being confused with sepsis, adverse effects of anti-arthritic drugs or exacerbated symptoms of evolving rheumatologic or infectious diseases. Because of the late diagnosis, most patients do not benefit from effective therapy, leading to death. Elucidation of valid early diagnostic criteria of MAS would be a particularly important step in reducing the mortality due to this pathology. Thus, the purpose of this review based on 40 studies centered on the diagnostic criteria of MAS. We detailed the main diagnostic criteria and the few diagnostic scores or sets of criteria that have been recently published. The criteria most frequently encountered in the literature include: Fever, hepatosplenomegaly, hyperferritinemia, hepatopathy, coagulopathy, thrombocytopenia, hypertriglyceridemia, decrease in erythrocyte sedimentation rate and bone marrow hemophagocytosis. The most elaborate diagnostic score will result following an ongoing international project and consensus, the Delphi International Survey.

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.

Clinical and laboratory signs of haemophagocytic lymphohistiocytosis associated with pandemic influenza A (H1N1) infection in patients needing extracorporeal membrane oxygenation: A retrospective observational study

BACKGROUND

Severe pandemic influenza has been associated with the hyperinflammatory condition secondary haemophagocytic lymphohistiocytosis (HLH).

OBJECTIVES

To determine the frequency, degree, character and possible cause of influenza-associated HLH in critically ill patients with severe acute respiratory distress syndrome due to influenza A (H1N1) infection requiring extracorporeal membrane oxygenation (ECMO) support at our hospital.

DESIGN

A retrospective observational study.

PATIENTS AND SETTING

Medical data were retrieved retrospectively from 11 consenting patients of thirteen adults infected with pandemic influenza A (H1N1) 2009 requiring ECMO between July 2009 and January 2010 at the ECMO Centre of Karolinska University Hospital, Stockholm, Sweden. All patients were evaluated for HLH using HLH-2004 criteria and HScore.

RESULTS

Eleven patients (median age 31 years) were included in the study and all survived. All patients showed signs of multiple organ dysfunction and pronounced inflammation, more severe in the four patients with HLH who had significantly higher peak serum concentrations of ferritin (P = 0.024), alkaline phosphatase (P = 0.012) and gamma-glutamyl transferase (P = 0.024), lower concentration of albumin (P = 0.0086) and more frequently hepatomegaly (P = 0.048). Abnormal lymphocyte cytotoxicity (lytic units <10) and a low proportion of natural killer (NK) cells were observed in three of four patients with HLH. Notably, we found a significant inverse correlation between serum ferritin concentration and NK cell and cytotoxic T lymphocyte percentages (rs = -0.74, P = 0.0013 and rs = -0.79, P = 0.0025, respectively). One HLH patient received HLH-directed cytotoxic therapy, another intravenous immunoglobulin and the other two no specific HLH-directed therapy.

CONCLUSION

Critically ill patients, including healthy young adults, with pandemic influenza may develop HLH and should be monitored for signs of hyperinflammation and increasing organ dysfunction, and evaluated promptly for HLH because HLH-directed therapy may then be beneficial. The association of low NK percentages with hyperferritinaemia may suggest a role for reduced NK cell numbers, possibly also cytotoxic T lymphocytes, and subsequently reduced lymphocyte cytotoxicity, in the pathogenesis of hyperinflammation and secondary HLH.

The Counter Regulatory Axis of the Lung Renin-Angiotensin System in Severe COVID-19: Pathophysiology and Clinical Implications

The severe acute respiratory syndrome coronavirus (SARS-CoV)-2, which is responsible for coronavirus disease 2019 (COVID-19), uses angiotensin (ANG)-converting enzyme 2 (ACE2) as the entrance receptor. Although most COVID-19 cases are mild, some are severe or critical, predominantly due to acute lung injury. It has been widely accepted that a counter regulatory renin-angiotensin system (RAS) axis including the ACE2/ANG [1-7]/Mas protects the lungs from acute lung injury. However, recent evidence suggests that the generation of protective ANG [1-7] in the lungs is predominantly mediated by proinflammatory prolyl oligopeptidase (POP), which has been repeatedly demonstrated to be involved in lung pathology. This review contends that acute lung injury in severe COVID-19 is characterised by a) ACE2 downregulation and malfunction (inflammatory signalling) due to viral occupation, and b) dysregulation of the protective RAS axis, predominantly due to increased activity of proinflammatory POP. It follows that a reasonable treatment strategy in COVID-19-related acute lung injury would be delivering functional recombinant (r) ACE2 forms to trap the virus. Additionally, or alternatively to rACE2 delivery, the potential benefits resulting from lowering POP activity should also be explored. These treatment strategies deserve further investigation.

Future Biomarkers for Infection and Inflammation in Febrile Children

Febrile patients, suffering from an infection, inflammatory disease or autoimmunity may present with similar or overlapping clinical symptoms, which makes early diagnosis difficult. Therefore, biomarkers are needed to help physicians form a correct diagnosis and initiate the right treatment to improve patient outcomes following first presentation or admittance to hospital. Here, we review the landscape of novel biomarkers and approaches of biomarker discovery. We first discuss the use of current plasma parameters and whole blood biomarkers, including results obtained by RNA profiling and mass spectrometry, to discriminate between bacterial and viral infections. Next we expand upon the use of biomarkers to distinguish between infectious and non-infectious disease. Finally, we discuss the strengths as well as the potential pitfalls of current developments. We conclude that the use of combination tests, using either protein markers or transcriptomic analysis, have advanced considerably and should be further explored to improve current diagnostics regarding febrile infections and inflammation. If proven effective when combined, these biomarker signatures will greatly accelerate early and tailored treatment decisions.

Serum biomarkers for prediction of mortality in patients with COVID-19

BACKGROUND

There is limited information regarding the role of biomarker levels at predicting mortality in patients with the coronavirus disease (COVID-19) pandemic. The purpose of this study is to determine the differences in serum biomarker levels in adults with COVID-19 who survived hospitalization from those who did not.

METHODS

A comprehensive search was completed on PubMed, EMBASE and Cochrane libraries to identify studies of interest. Endpoints of interest were blood counts, hepatic function test, acute phase reactants, cytokines and cardiac biomarkers.

RESULTS

A total of 10 studies with 1584 patients were included in the pooled analyses. Biomarkers that were noted to be significantly higher in those who died from coronavirus disease included: white blood cell count, neutrophil count, C-reactive protein, high sensitivity C-reactive protein, procalcitonin, ferritin, D-dimer, interleukin-6, lactate dehydrogenase, creatine kinase, prothrombin time, aspartate aminotransferase, alanine aminotransferase, total bilirubin and creatinine. Lymphocyte count, platelet count and albumin were significantly lower in patients who died.

CONCLUSION

This pooled analysis of 10 studies including 1584 patients identified significant differences in biomarkers on admission in patients who survived from those who did not. Further research is needed to develop risk stratification models to help with judicious use of limited health-care resources.

Reactions Related to CAR-T Cell Therapy

The application of chimeric antigen receptor (CAR) T-cell therapy as a tumor immunotherapy has received great interest in recent years. This therapeutic approach has been used to treat hematological malignancies solid tumors. However, it is associated with adverse reactions such as, cytokine release syndrome (CRS), immune effector cell-associated neurotoxicity syndrome (ICANS), off-target effects, anaphylaxis, infections associated with CAR-T-cell infusion (CTI), tumor lysis syndrome (TLS), B-cell dysplasia, hemophagocytic lymphohistiocytosis (HLH)/macrophage activation syndrome (MAS) and coagulation disorders. These adverse reactions can be life-threatening, and thus they should be identified early and treated effectively. In this paper, we review the adverse reactions associated with CAR-T cells, the mechanisms driving such adverse reactions, and strategies to subvert them. This review will provide important reference data to guide clinical application of CAR-T cell therapy.

Na+/K+-ATPase as a Target of Cardiac Glycosides for the Treatment of SARS-CoV-2 Infection

Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), identified for the first time in Wuhan, China, causes coronavirus disease 2019 (COVID-19), which moved from epidemic status to becoming a pandemic. Since its discovery in December 2019, there have been countless cases of mortality and morbidity due to this virus. Several compounds such as chloroquine, hydroxychloroquine, lopinavir-ritonavir, and remdesivir have been tested as potential therapies; however, no effective treatment is currently recommended by regulatory agencies. Some studies on respiratory non-enveloped viruses such as adenoviruses and rhinovirus and some respiratory enveloped viruses including human respiratory syncytial viruses, influenza A, parainfluenza, SARS-CoV, and SARS-CoV-2 have shown the antiviral activity of cardiac glycosides, correlating their effect with Na⁺/K⁺-ATPase (NKA) modulation. Cardiac glycosides are secondary metabolites used to treat patients with cardiac insufficiency because they are the most potent inotropic agents. The effects of cardiac glycosides on NKA are dependent on cell type, exposure time, and drug concentration. They may also cause blockage of Na⁺ and K⁺ ionic transport or trigger signaling pathways. The antiviral activity of cardiac glycosides is related to cell signaling activation through NKA inhibition. Nuclear factor kappa B (NFκB) seems to be an essential transcription factor for SARS-CoV-2 infection. NFκB inhibition by cardiac glycosides interferes directly with SARS-CoV-2 yield and inflammatory cytokine production. Interestingly, the antiviral effect of cardiac glycosides is associated with tyrosine kinase (Src) activation, and NFκB appears to be regulated by Src. Src is one of the main signaling targets of the NKA α-subunit, modulating other signaling factors that may also impair viral infection. These data suggest that Src-NFκB signaling modulated by NKA plays a crucial role in the inhibition of SARS-CoV-2 infection. Herein, we discuss the antiviral effects of cardiac glycosides on different respiratory viruses, SARS-CoV-2 pathology, cell signaling pathways, and NKA as a possible molecular target for the treatment of COVID-19.