Haemophagocytic lymphohistiocytosis in adult critical care

Hemophagocytic lymphohistiocytosis in pregnancy-a case report

Hemophagocytic lymphohistiocytosis (HLH) is a life-threatening condition that is a rare occurrence in pregnancy and can be elusive in its diagnosis thereby delaying treatment. We report the case of a 30-year-old female patient at 36 weeks of pregnancy who presented with a persistent fever that did not respond to antibiotics. After we investigated her thoroughly, considering the persistent fever, we performed a bone marrow biopsy as part of the workup for prolonged pyrexia. We diagnosed her with HLH secondary to cytomegalovirus pneumonia. As her laboratory investigations fulfilled the criteria for HLH we treated her with the appropriate therapy using a multidisciplinary approach, resulting in her complete recovery. HLH should be considered a potential differential diagnosis in pregnant patients complaining of persistent fever, cytopenia, or declining clinical condition despite delivery of the baby.

Tocilizumab and immune signatures for targeted management of cytokine release syndrome in immune checkpoint therapy

BACKGROUND

This study aimed to identify specific biomarkers in oncology patients experiencing immune-related cytokine release syndrome (irCRS)-like symptoms during immune checkpoint inhibitor (ICI) therapy, including severe cases like hemophagocytic lymphohistiocytosis (irHLH), and to distinguish these from sepsis. A secondary objective was to retrospectively analyze the efficacy of tocilizumab (TCZ) in treating corticosteroid (CS)-refractory high-grade irCRS.

PATIENTS AND METHODS

A cohort of 35 patients presenting with irCRS-like symptoms was studied, including 9 with irHLH-like manifestations and 8 with sepsis. Immune profiling was carried out using 48 mass cytometry markers, along with an analysis of 45 serum biomarkers, including 27 cytokines and 18 additional markers from the HScore. Twelve patients with high-grade irCRS refractory to CS were treated with TCZ.

RESULTS

Twenty-four biomarkers significantly distinguished between irHLH and grade 3 irCRS (P = 0.0027-0.0455). Hepatocyte growth factor (HGF) and ferritin had superior predictive values compared with the traditional HScore, both with a positive predictive value (PPV) and negative predictive value (NPV) of 100%. CXCL9 differentiated irHLH from grade 3 irCRS and predicted the need for TCZ treatment intensification (PPV = 90%, NPV = 100%). Additional biomarkers, including leukocyte count, neutrophils, ferritin, interleukin (IL)-6, IL-7, epidermal growth factor, fibrinogen, and granulocyte-macrophage colony-stimulating factor (GM-CSF), discriminated sepsis from high-grade irCRS (PPV = 75%-80%, NPV = 100%). Elevated frequencies of CXCR5+ or CCR4+ CD8 memory cells, CD38+ intermediate monocytes, and CD62L+ neutrophils were observed in high-grade irCRS compared with sepsis. All 12 patients with high-grade irCRS refractory to CS treated with TCZ experienced complete resolution.

CONCLUSIONS

This study highlights the importance of specific immunologic biomarkers in determining irCRS severity, predicting outcomes, and distinguishing between irHLH, irCRS, and sepsis. It also demonstrates the efficacy of TCZ in managing high-grade irCRS, underscoring the need for personalized therapeutic strategies based on these biomarkers.

Markers of Hemophagocytic Lymphohistiocytosis Are Associated with Mortality in Critically Ill Patients

Background: Critically ill patients often display systemic immune dysregulation and increased inflammatory activity. Hemophagocytic lymphohistiocytosis (HLH) represents a rare syndrome defined by the inappropriate survival of cytotoxic T cells and the occurrence of cytokine storms. Although HLH is characterized by relatively high mortality rates, little is known about the predictive value of its diagnostic criteria. Accordingly, our objective was to evaluate these properties within an unselected cohort of critically ill patients admitted to a tertiary intensive care unit (ICU). Methods: This single-center prospective observational study included 176 consecutive patients. Available HLH criteria at admission were assessed, including sCD25 measurements performed using ELISA. Results: Overall, 30-day mortality rates were significantly higher in patients exhibiting two or more criteria of HLH (21.9% vs. 43.3%, p = 0.033). Moreover, sCD25 emerged as an independent risk predictor of 30-day mortality independent of age, sex, the use of vasopressors, and mechanical ventilation (HR 2.72 for the highest tertile vs. lowest tertile, p = 0.012). Additionally, fibrinogen was significantly decreased in non-survivors (p = 0.019), and its addition to the SAPS II score significantly increased its prognostic capability (p = 0.045). In contrast, ferritin and triglyceride levels were not different in survivors versus non-survivors. Conclusions: Critically ill patients displaying two or more HLH criteria exhibit a dramatic increase in 30-day mortality, even in the absence of an established HLH diagnosis. Furthermore, elevated levels of sCD25 and decreased levels of fibrinogen were found to be significant predictors of mortality.

Optimising Care for Haemophagocytic Lymphohistiocytosis in District General Hospitals: Best Practice Insights and Review of Literature

Haemophagocytic lymphohistiocytosis (HLH) is a hyper-inflammatory syndrome characterised by widespread, uncontrolled T cell and histiocyte activation with accompanying cytokine storm. It can be inherited or acquired, with acquired forms triggered by infection, malignancy or autoimmune disease. There is high mortality, with patients commonly requiring critical care support. HLH is a relatively rare condition (though it is likely underdiagnosed), and there is an incomplete understanding of its pathogenesis, diagnosis and optimal management. As such, HLH presents a challenge to the critical care physician, particularly in a non-specialist centre. In our District General Hospital (DGH) intensive therapy unit, we experienced an unusually high volume of HLH cases in a short period. By presenting this case series and our improvement strategies, we aim to distil key lessons to other centres to improve the understanding of HLH for critical care physicians. There were seven confirmed cases of HLH between January 2022 and August 2024. We analysed each case, in turn, documenting the initial symptomatology, blood test results, including ferritin, and when specialist teams such as haematology and critical care became involved. We then noted when HLH treatment was started and the outcome of each case. We found that implementing a protocol to encourage early requests of an HLH blood test panel and, thereafter, early review and input by the local haematology teams, as well as critical care input for any patient with suspected HLH, improved patient outcomes: two patients died during admission pre-intervention. However, none of the patients died within their admission after our interventions. We also found that pharmacy input to ensure the emergency stock of medications used to treat HLH allowed more prompt administration of HLH treatment. Although the cornerstone of management for the critical care physician includes supportive care and organ support, HLH-specific treatments targeting the underpinning inflammation and the cytokine storm are also pivotal to controlling the disease process. Early escalation to the haematology team based on abnormally high ferritin levels and early critical care input was the cornerstone of the pathway we developed in our hospital. This system that has been developed will stand to be useful in other DGHs where HLH remains an unfamiliar condition that carries a high mortality rate.

Beyond Septic Encephalopathy: A Case Report of Severe RCVS and PRES in a Patient With HLH due to Appendicitis

Background and Objectives: We report a rare case of severe posterior reversible encephalopathy syndrome (PRES) and reversible cerebral vasoconstriction syndrome (RCVS) in an adult patient with hemophagocytic lymphohistiocytosis (HLH), and speculate that these three diagnoses are related by similar mechanisms of vascular endothelial dysfunction. Methods: Informed consent for this case report was obtained from the patient's legally authorized surrogate decision maker. Discussion and Practical Implications: Our patient initially presented with HLH secondary to intra-abdominal sepsis, and was later found to have severe PRES and RCVS resulting in extensive border-zone cortex infarction. Improvement of the severe systemic inflammatory syndrome characteristic of HLH and arrest of PRES and RCVS progression occurred only after HLH-specific treatment was initiated. In addition to illustrating the potential of HLH to manifest as PRES and RCVS, this case emphasizes the importance of prompt recognition and treatment of HLH and the role the neurologist can play in this process. This case also sheds light on the pathophysiological links between PRES, RCVS, and HLH. These three diagnoses may be related by similar mechanisms of vascular endothelial dysfunction caused by uncontrolled and severe systemic inflammation.

Immune biomarkers and secondary hemophagocytic lymphohistiocytosis: a scoping review protocol

OBJECTIVE

The objective of this review is to identify immunological pathways and markers of severity of illness associated with clinical outcomes that may represent potential therapeutic targets in the management of secondary hemophagocytic lymphohistiocytosis.

INTRODUCTION

A broad range of immunomodulatory therapies is used to manage hemophagocytic lymphohistiocytosis, however, the supporting evidence for these therapies is scarce. Identifying patients likely to experience more severe disease or die is currently extremely difficult, if not impossible. The identification of implicated cytokines in secondary disease can provide further support for the identification of high-risk patients and the development of targeted therapies.

INCLUSION CRITERIA

Studies reporting immune biomarker and cytokine measurement in adult patients (age ≥18 years) with secondary hemophagocytic lymphohistiocytosis will be considered for inclusion.

METHODS

The proposed review will be conducted in line with the JBI methodology for scoping reviews. MEDLINE (Ovid) and Embase (Ovid) will be searched, without date limitations. Data will be extracted using a data extraction tool developed by the reviewers. Relevant sources will be retrieved, and their citation details imported into the JBI System for the Unified Management, Assessment and Review of Information.

REVIEW REGISTRATION

Open Science Framework https://osf.io/9524e.

Prognostic Impact of Aetiology in Adult Hemophagocytic Lymphohistiocytosis: Insights from an Intensive Care Unit Experience

Background

Hemophagocytic lymphohistiocytosis (HLH) is a rare, life-threatening hyperinflammatory syndrome marked by excessive immune activation. It can be triggered by various factors, including infections, malignancies, and autoimmune diseases, making the diagnosis challenging due to its overlap with other severe conditions.

Case reports

We discuss two intensive care unit (ICU) cases illustrating the diverse manifestations of HLH and the critical importance of early recognition and treatment. The first case involves natural killer-cell leukaemia, and the second, a suspected viral trigger. Both highlight the necessity of a multidisciplinary approach in diagnosis and management, emphasizing the complexity of HLH in ICU settings.

Conclusions

High mortality rates, particularly in malignancy-associated HLH, underscore the importance of tailored treatment strategies based on the underlying aetiology.

LEARNING POINTS

Hemophagocytic lymphohistiocytosis (HLH) in adults can arise from a variety of triggers, including infections and malignancies, each influencing disease progression and prognosis differently. Recognizing these underlying aetiologies is crucial for tailoring management strategies and anticipating clinical outcomes.Due to its life-threatening nature, HLH requires prompt diagnosis and a coordinated, multidisciplinary approach. Early intervention, incorporating immunosuppressive therapies and supportive care, is essential to improve patient outcomes, particularly in intensive care unit settings where disease severity is often pronounced.Utilizing diagnostic tools such as the HScore and HLH-2004 criteria can facilitate early identification of HLH in critically ill patients with unexplained inflammatory symptoms. These tools, along with a high index of suspicion, help distinguish HLH from other hyperinflammatory conditions, enabling timely and appropriate therapeutic interventions.

Into the storm: the imbalance in the yin-yang immune response as the commonality of cytokine storm syndromes

There is a continuous cycle of activation and contraction in the immune response against pathogens and other threats to human health in life. This intrinsic yin-yang of the immune response ensures that inflammatory processes can be appropriately controlled once that threat has been resolved, preventing unnecessary tissue and organ damage. Various factors may contribute to a state of perpetual immune activation, leading to a failure to undergo immune contraction and development of cytokine storm syndromes. A literature review was performed to consider how the trajectory of the immune response in certain individuals leads to cytokine storm, hyperinflammation, and multiorgan damage seen in cytokine storm syndromes. The goal of this review is to evaluate how underlying factors contribute to cytokine storm syndromes, as well as the symptomatology, pathology, and long-term implications of these conditions. Although the recognition of cytokine storm syndromes allows for universal treatment with steroids, this therapy shows limitations for symptom resolution and survival. By identifying cytokine storm syndromes as a continuum of disease, this will allow for a thorough evaluation of disease pathogenesis, consideration of targeted therapies, and eventual restoration of the balance in the yin-yang immune response.

Successful Treatment of Severe Steroid-Resistant Engraftment Syndrome Following Haploidentical Allogeneic Hematopoietic Stem Cell Transplantation for Acute Myeloid Leukemia with Emapalumab: A Case Report

Engraftment syndrome (ES) is an early complication of hematopoietic stem cell transplantation (HSCT) characterized by fever and additional clinical manifestations including rash, diarrhea, lung infiltrates, weight gain, and neurological symptoms. Steroid-resistant ES following HSCT significantly affects the efficacy of transplantation and may even result in patient mortality. As ES essentially represents a cytokine storm induced by engrafted donor cells with interferon-gamma (IFN-γ) playing a central role, we hypothesized that emapalumab (an anti-IFN-γ monoclonal antibody) may be an effective approach to treat steroid-resistant ES. Here, we present a case report of a 14-year-old female patient who received a second haploidentical HSCT due to a relapse of acute myeloid leukemia. Nine days after the transplantation, the patient developed a fever and exhibited a poor response to antimicrobials (ceftazidime/avibactam). A few days later, the patient presented with a new-onset rash, weight gain, and impaired liver function, leading to a diagnosis of ES. Initial immunosuppressive (tacrolimus and mycophenolate mofetil) treatment failed to control the disease. On day 16 post-transplantation, the patient received two infusions of 50 mg of emapalumab. Following the initiation of emapalumab treatment, the patient's fever returned to normal and ES was effectively controlled. This case report demonstrated that emapalumab had a possible efficacy for steroid-resistant ES and provided a novel therapeutic strategy to treat this clinical complication.

X-linked Inhibitor of Apoptosis (XIAP) Deficiency Complicated by Hemophagocytic Lymphohistiocytosis on Immunotherapy Leading to Acute Respiratory Distress Syndrome and Multiorgan Failure Secondary to Opportunistic Infections

X-linked inhibitor of apoptosis (XIAP) deficiency is a rare primary immunodeficiency with a broad spectrum of clinical manifestations, including susceptibility to hemophagocytic lymphohistiocytosis (HLH), inflammatory bowel disease (IBD), hypogammaglobulinemia, and severe infections. We present a case of a 39-year-old male with a past medical history of XIAP deficiency complicated by HLH, Crohn's disease, and hypogammaglobulinemia, who developed acute respiratory distress syndrome (ARDS) due to Pneumocystis jiroveci pneumonia (PJP) and concurrent multiorgan failure due to disseminated Mycobacterium avium intracellulare (MAI) infection. This case highlights the challenges in managing XIAP deficiency, emphasizing the importance of early recognition, and the need for further research to improve outcomes in this population.

[Hemophagocytic lymphohistiocytosis and macrophage activation syndrome : A multidisciplinary challenge]

Hemophagocytic lymphohistiocytosis (HLH) is a life-threatening hyperinflammatory syndrome that is characterized by hyperferritinemia, cytopenia, disseminated intravascular coagulopathy and functional disorders of the liver and the central nervous system. The term macrophage activation syndrome is predominantly used for secondary HLH in the context of autoimmune diseases (e.g., systemic juvenile idiopathic arthritis). In addition, malignancies and genetic inborn errors of immunity can predispose to the development of HLH. Infections (e.g., Epstein-Barr virus) in turn represent possible triggers of an acute episode. Due to the unspecific manifestation of the disease, a systematic evaluation of the organ systems is recommended in the clinical and laboratory analytical clarification of hyperinflammatory syndromes. In general, the treatment should be carried out by a multidisciplinary team with expertise in rheumatology, hematological oncology, infectious diseases and intensive care medicine. The primary treatment of HLH usually consists of glucocorticoids and in cases of a rapid deterioration of the condition anakinra (interleukin 1 block) and intravenous immunoglobulins can be employed. Treatment of the underlying disease should be consequently carried out in parallel, together with antimicrobial treatment.

Hemophagocytic Lymphohistiocytosis: A Case Report

The hemophagocytic syndrome (HS) or hemophagocytic lymphohistiocytosis (HLH) is a syndrome with apoptosis deficiency that results in the impairment of a regulatory pathway with consequent immune and inflammatory responses. Fever, cytopenias, splenomegaly, and hemophagocytosis are cardinal signs. It may be familial or secondary to infection, autoimmunity, or neoplasia. Impaired natural killer (NK)-cell cytotoxicity is the hallmark of HLH. All genetic defects in familial HLH are related to granule-dependent cytotoxicity. The authors present a 50-year-old black female patient with a history of drepanocytosis who attended the emergency department due to fever, asthenia, lethargy, and hypogastric pain. Her laboratory workup on admission revealed severe pancytopenia. She was ultimately diagnosed with HLH due to sepsis of urinary origin, with a fatal outcome. HLH is a rare and life-threatening syndrome. The delay in its diagnosis due to the variability of the clinical and laboratory findings constitutes the main obstacle to a successful prognosis, as illustrated in this case report.

Cytokine Storm and Sepsis-Induced Multiple Organ Dysfunction Syndrome

There is extensive overlap of clinical features among familial or primary HLH (pHLH), reactive or secondary hemophagocytic lymphohistiocytosis (sHLH) [including macrophage activation syndrome (MAS) related to rheumatic diseases], and hyperferritinemic sepsis-induced multiple organ dysfunction syndrome (MODS); however, the distinctive pathobiology that causes hyperinflammatory process in each condition requires careful considerations for therapeutic decision-making. pHLH is defined by five or more of eight HLH-2004 criteria [1], where genetic impairment of natural killer (NK) cells or CD8+ cytolytic T cells results in interferon gamma (IFN-γ)-induced hyperinflammation regardless of triggering factors. Cytolytic treatments (e.g., etoposide) or anti-IFN-γ monoclonal antibody (emapalumab) has been effectively used to bridge the affected patients to hematopoietic stem cell transplant. Secondary forms of HLH also have normal NK cell number with decreased cytolytic function of varying degrees depending on the underlying and triggering factors. Although etoposide was uniformly used in sHLH/MAS in the past, the treatment strategy in different types of sHLH/MAS is increasingly streamlined to reflect the triggering/predisposing conditions, severity/progression, and comorbidities. Accordingly, in hyperferritinemic sepsis, the combination of hepatobiliary dysfunction (HBD) and disseminated intravascular coagulation (DIC) reflects reticuloendothelial system dysfunction and defines sepsis-associated MAS. It is demonstrated that as the innate immune response to infectious organism prolongs, it results in reduction in T cells and NK cells with subsequent lymphopenia even though normal cytolytic activity continues (Figs. 30.1, 30.2, 30.3, and 30.4). These changes allow free hemoglobin and pathogens to stimulate inflammasome activation in the absence of interferon-γ (IFN-γ) production that often responds to source control, intravenous immunoglobulin (IVIg), plasma exchange, and interleukin 1 receptor antagonist (IL-1Ra), similar to non-EBV, infection-induced HLH.

Diagnosis and investigation of suspected haemophagocytic lymphohistiocytosis in adults: 2023 Hyperinflammation and HLH Across Speciality Collaboration (HiHASC) consensus guideline

Haemophagocytic lymphohistiocytosis (HLH) is a hyperinflammatory syndrome characterised by persistently activated cytotoxic lymphocytes and macrophages, which, if untreated, leads to multiorgan dysfunction and death. HLH should be considered in any acutely unwell patient not responding to treatment as expected, with prompt assessment to look for what we term the three Fs-fever, falling blood counts, and raised ferritin. Worldwide, awareness of HLH and access to expert management remain inequitable. Terminology is not standardised, classification criteria are validated in specific patient groups only, and some guidelines rely on specialised and somewhat inaccessible tests. The consensus guideline described in this Health Policy was produced by a self-nominated working group from the UK network Hyperinflammation and HLH Across Speciality Collaboration (HiHASC), a multidisciplinary group of clinicians experienced in managing people with HLH. Combining literature review and experience gained from looking after patients with HLH, it provides a practical, structured approach for all health-care teams managing adult (>16 years) patients with possible HLH. The focus is on early recognition and diagnosis of HLH and parallel identification of the underlying cause. To ensure wide applicability, the use of inexpensive, readily available tests is prioritised, but the role of specialist investigations and their interpretation is also addressed.

Iatrogenic HLH

Hemophagocytic lymphohistiocytosis (HLH) can be categorized as either primary (familial, generally occurring in infants) or secondary (sHLH, occurring at any age in association with a variety of conditions) and is mainly triggered by infections, autoimmune diseases, and malignant conditions. Our understanding of the pathophysiology of sHLH is still evolving, and among the causes and associations with the syndrome, those putatively associated with iatrogenic causes remain among the most poorly understood due to the rarity of these entities and the multiple confounders so often present in the patients in whom they are reported. Herein, we present a review of the literature to describe the diagnostic and therapeutic challenges of sHLH associated with iatrogenic causes and discuss some of the challenges and future directions in our efforts to better understand these complex conditions for the advancement of patient outcomes.

Anakinra Removal by Continuous Renal Replacement Therapy: An Ex Vivo Analysis

OBJECTIVES

Patients with sepsis are at significant risk for multiple organ dysfunction, including the lungs and kidneys. To manage the morbidity associated with kidney impairment, continuous renal replacement therapy (CRRT) may be required. The extent of anakinra pharmacokinetics in CRRT remains unknown. The objectives of this study were to investigate the anakinra-circuit interaction and quantify the rate of removal from plasma.

DESIGN

The anakinra-circuit interaction was evaluated using a closed-loop ex vivo CRRT circuit. CRRT was performed in three phases based on the method of solute removal: 1) hemofiltration, 2) hemodialysis, and 3) hemodiafiltration. Standard control samples of anakinra were included to assess drug degradation.

SETTING

University research laboratory.

PATIENTS

None.

INTERVENTIONS

Anakinra was administered to the CRRT circuit and serial prefilter blood samples were collected along with time-matched control and hemofiltrate samples. Each circuit was run in triplicate to assess inter-run variability. Concentrations of anakinra in each reference fluid were measured by enzyme-linked immunosorbent assay. Transmembrane filter clearance was estimated by the product of the sieving coefficient/dialysate saturation constant and circuit flow rates.

MEASUREMENTS AND MAIN RESULTS

Removal of anakinra from plasma occurred within minutes for each CRRT modality. Average drug remaining (%) in plasma following anakinra administration was lowest with hemodiafiltration (34.9%). The average sieving coefficient was 0.34, 0.37, and 0.41 for hemodiafiltration, hemofiltration, and hemodialysis, respectively. Transmembrane clearance was fairly consistent across each modality with the highest during hemodialysis (5.53 mL/min), followed by hemodiafiltration (4.99 mL/min), and hemofiltration (3.94 mL/min). Percent drug remaining within the control samples (93.1%) remained consistent across each experiment, indicating negligible degradation within the blood.

CONCLUSIONS

The results of this analysis are the first to demonstrate that large molecule therapeutic proteins such as anakinra, are removed from plasma with modern CRRT technology. Current dosing recommendations for patients with severe renal impairment may result in subtherapeutic anakinra concentrations in those receiving CRRT.

Hemophagocytic Lymphohistiocytosis Secondary to Obstructive Uropathy and Escherichia coli Bacteremia

Hemophagocytic lymphohistiocytosis (HLH) is a rare syndrome in which widespread activation of the immune system causes multi-organ tissue damage. HLH is a serious and potentially fatal disorder characterized by excessive immune system activation. It is characterized by a dysregulation in natural killer (NK) T-cell function, causing activation of lymphocytes and histiocytes. These cells secrete a large number of inflammatory cytokines and infiltrate various tissues causing multi-organ system failure. The spectrum consists of hereditary or "primary" HLH that comprises genetically heterogeneous conditions, occurring during childhood. The secondary form presents later in life and is associated with several conditions mainly malignancy, autoimmune diseases, viral or bacterial infections, and hematological diseases. Here we present an interesting case in which a 39-year-old patient presented with a complaint of shortness of breath. He was diagnosed with obstructive uropathy in the emergency department and subsequently developed acute liver injury, acute kidney injury, Escherichia coli bacteremia, and was diagnosed with HLH with comorbid bacteremia.

Severe Mycobacterial Immune Reconstitution Inflammatory Syndrome (IRIS) in Advanced Human Immunodeficiency Virus (HIV) Has Features of Hemophagocytic Lymphohistiocytosis and Requires Prolonged Immune Suppression

BACKGROUND

People with HIV and mycobacterial infections can develop immune reconstitution inflammatory syndrome (IRIS) after starting antiretroviral therapy (ART). Severe mycobacterial IRIS has an overlapping clinical phenotype with hemophagocytic lymphohistiocytosis (HLH). We evaluated the pathophysiologic similarities between mycobacterial IRIS and HLH to identify clinical and immune predictors of mycobacterial IRIS severity.

METHODS

HLH criteria were applied to a longitudinal cohort of 80 patients with HIV (CD4 <100 cells/µL) and mycobacterial infections. Participants were subdivided into IRIS meeting HLH criteria (HLH-IRIS), IRIS without HLH (IRIS), and those without IRIS (non-IRIS). Clinical outcomes were evaluated by regression analyses. Soluble biomarkers and T-cell subsets were assessed at baseline and IRIS-equivalent time points.

RESULTS

HLH-IRIS patients required corticosteroids more frequently (OR: 21.5; 95%CI: 5.6-114.8) and for longer duration (21.2; 95%CI: 10.7-31.7 weeks) than those not meeting HLH criteria. Utilizing decision tree analyses, hemoglobin <9.2 g/dL was the best predictor of HLH-IRIS before ART, whereas ferritin, CXCL9 and sCD25 were most diagnostic for HLH at IRIS onset. At the IRIS timepoint, but not baseline, HLH-IRIS patients had lower regulatory and higher activated T cells along with greater production of IFNγ-IL-18 axis biomarkers compared with both IRIS and non-IRIS groups. Principal component analysis corroborated the distinct clustering of HLH-IRIS patients.

CONCLUSIONS

Severe mycobacterial IRIS and HLH have an overlapping pathogenesis involving IFNγ and unopposed T-cell activation causing severe inflammatory disease clinically distinguished by hyperferritinemia (hyperferritinemic IRIS [FIRIS]). Hemoglobin, ferritin, CXCL9, and sCD25 identify high-risk patients and may improve risk stratification and therapeutic strategies for mycobacterial IRIS.

"A Dangerous Black Box:" Idiopathic Hemophagocytic Lymphohistiocytosis in Adult Patients-A Case Report and Review of the Literature

Hemophagocytic lymphohistiocytosis (HLH) is a rare potentially life-threatening condition characterized by aberrant inflammation that can be related to genetic or sporadic forms. In both forms, triggering factors may be involved. Early detection of the underlying cause is crucial for therapeutic decision, while early intervention might be associated with better outcomes. The largest descriptions in the literature on HLH refer to pediatric cases. Adolescents and adults may also be affected, but there is scarce evidence regarding their diagnosis and management. We describe here the case of a 68-year-old Swiss woman with HLH, in whom an extensive search for underlying causes was performed, but neither trigger nor pathogenic variant was found. An early intervention first with dexamethasone and later with cyclosporine was performed. The patient showed a favorable response and did not require further hospitalization; however, one year after diagnosis, it was not possible to suspend cyclosporine due to recurrence of laboratory inflammation signs by drug tapering. The occurrence of HLH idiopathic forms represents a challenge; failure to identify the underlying triggering cause generates uncertainty, endless diagnostic investigations, and consequently additional delays in the treatment. This manuscript addresses the difficulties on this issue.

Anakinra for the Treatment of Hemophagocytic Lymphohistiocytosis: 21 Cases

Hemophagocytic lymphohistiocytosis (HLH) is a life-threatening cytokine storm syndrome. There are no definitive guidelines for the management of secondary HLH (sHLH). A recent report by a National Health Service (NHS) clinical panel has recommended anakinra as a treatment option. We aimed to analyse the efficacy and safety of anakinra for the treatment of all-cause sHLH. We conducted a multicentric retrospective study in two French University hospitals and included all patients who had a diagnosis of sHLH and who received anakinra. Among 21 patients (median age, 45 years), 13 were men. Anakinra was used as first-line therapy in 10 patients, and as monotherapy in 5 patients. We found that anakinra was effective in 19/21 patients (90.5%), with fever resolution in 19 patients (90.5%) within a median of 1.0 day (1, 2). At the Day 7 assessment, the mean CRP concentration decreased significantly (p < 0.001), as did the mean ferritin (p = 0.011). Anakinra was generally safe and well tolerated and was discontinued for side effects in only three patients (14.3%). Anakinra is an efficient and safe treatment to control sHLH of various causes. These data, together with the recent report of the NHS panel, call for the rapid conduct of prospective randomized clinical trials.

Murine typhus complicated by sHLH mimicking adult-onset Still's disease

INTRODUCTION

Adult-onset Still's disease (AOSD) is a rare multisystemic disorder and a diagnostic challenge for physicians because of the wide range of differential diagnoses. Common features of AOSD and secondary hemophagocytic lymphohistiocytosis (sHLH) could favour diagnostic uncertainty, in particular in case of infection-related sHLH.

OBSERVATION

A 61-year-old man was admitted to our internal medicine department for suspected AOSD. He reported a 2-week history of sudden onset fever, headaches, myalgia, sore throat, diarrhoea, and an erythematous macular rash of the trunk as well as petechial purpuric lesions on both legs on return from Reunion Island. Laboratory tests found cytopenia, hepatic cytolysis, hypertriglyceridaemia, and hyperferritinaemia. Hemophagocytosis was diagnosed on bone marrow aspiration in favour of the diagnosis of secondary hemophagocytic lymphohistiocytosis (sHLH). Subcutaneous anakinra (100mg) was initiated to treat sHLH with favourable course. Oral doxycycline was added 3days later because of atypical features for AOSD diagnosis such as diarrhoea, hypergammaglobulinaemia, and doubtful serologies for Rickettsia and Coxiella. Three weeks later, Rickettsia typhi serology was checked again and revealed an increase in IgG titer>4 times that confirmed the diagnosis of murine typhus. A diagnosis of murine typhus complicated by sHLH was retained, successfully treated by anakinra and doxycycline.

CONCLUSION

Our observation shows that AOSD diagnosis has to be stringent due to the many differential diagnoses, particularly infection complicated by sHLH, which may be rare. It is important to consider murine typhus in patients returning from endemic areas, such as La Reunion or other tropical areas, when they present fever of unknown origin with non-specific clinical features. Moreover, this case illustrates the effectiveness of IL-1 blockers as a treatment for symptomatic sHLH without severity criteria, regardless of the aetiology.

Still's Disease Mortality Trends in France, 1979-2016: A Multiple-Cause-of-Death Study

Still’s disease (SD) is often considered a benign disease, with low mortality rates. However, few studies have investigated SD mortality and its causes and most of these have been single-center cohort studies. We sought to examine mortality rates and causes of death among French decedents with SD. We performed a multiple-cause-of-death analysis on data collected between 1979 and 2016 by the French Epidemiological Center for the Medical Causes of Death. SD-related mortality rates were calculated and compared with the general population (observed/expected ratios, O/E). A total of 289 death certificates mentioned SD as the underlying cause of death (UCD) (n = 154) or as a non-underlying causes of death (NUCD) (n = 135). Over the study period, the mean age at death was 55.3 years (vs. 75.5 years in the general population), with differences depending on the period analyzed. The age-standardized mortality rate was 0.13/million person-years and was not different between men and women. When SD was the UCD, the most frequent associated causes were cardiovascular diseases (n = 29, 18.8%), infections (n = 25, 16.2%), and blood disorders (n = 11, 7.1%), including six cases (54%) with macrophage activation syndrome. As compared to the general population, SD decedents aged <45 years were more likely to die from a cardiovascular event (O/E = 3.41, p < 0.01); decedents at all ages were more likely to die from infection (O/E = 7.96–13.02, p < 0.001).

Hemophagocytic lymphohistiocytosis in COVID-19: Case reports of a stepwise approach

RATIONALE

The immunologic syndrome induced by severe acute coronavirus disease 2019 (COVID-19) is yet not fully understood. Typical patterns of clinical and laboratory features match secondary hemophagocytic lymphohistiocytosis (sHLH). However, the optimal approach to COVID-19 patients testing positive for sHLH is still unclear.

PATIENT CONCERNS

Three patients with COVID-19 are reviewed. All showed hyperinflammation and cytokine storm, necessitating intensive care treatment including mechanical ventilation.

DIAGNOSIS

Secondary hemophagocytic lymphohistiocytosis due to severe COVID-19; diagnosed via HScore.

INTERVENTIONS

A treatment regimen of methylprednisolone, pentaglobin, and anakinra was developed and administered.

OUTCOMES

One patient survived the ICU stay. Two other patients, in whom sHLH was diagnosed too late, deceased.

LESSONS

A routine screening of COVID-19 patients for secondary HLH by using the HScore is feasible; especially those patients deteriorating clinically with no sufficient response to shock management might be at particular high risk. A stepwise therapeutic approach comprising corticosteroids, immunoglobulins and anakinra, accompanied by immunoadsorption, may dampen cytokine storm effects, and potentially reduce mortality.

An Intriguing Presentation of Epstein-Barr Virus-Associated Hemophagocytic Lymphohistiocytosis

Hemophagocytic lymphohistiocytosis (HLH) is an immune related clinical syndrome with protean manifestations, varying presentation, clinically complex, with diverse causes, and is an under-recognized entity which carries high morbidity and mortality. It is precipitated by an immunological trigger in a susceptible host resulting in immune activation and dysregulation leading to disruption of immune homeostasis, cytokine storm and multi-organ failure. We describe a case of Epstein-Barr virus (EBV) associated HLH with its typical diagnostic challenges and associated high mortality rate. Certain diagnostic criteria and online tools may help to arrive at an earlier presumptive diagnosis which, in turn, may expedite treatment and lead to better clinical outcomes.

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

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