Challenges in the diagnosis of hemophagocytic lymphohistiocytosis: Recommendations from the North American Consortium for Histiocytosis (NACHO)

Impaired STING Activation Due to a Variant in the E3 Ubiquitin Ligase AMFR in a Patient with Severe VZV Infection and Hemophagocytic Lymphohistiocytosis

Varicella zoster virus (VZV) is a neurotropic alphaherpesvirus exclusively infecting humans, causing two distinct pathologies: varicella (chickenpox) upon primary infection and herpes zoster (shingles) following reactivation. In susceptible individuals, VZV can give rise to more severe clinical manifestations, including disseminated infection, pneumonitis, encephalitis, and vasculopathy with stroke. Here, we describe a 3-year-old boy in whom varicella followed a complicated course with thrombocytopenia, hemorrhagic and necrotic lesions, pneumonitis, and intermittent encephalopathy. Hemophagocytic lymphohistiocytosis (HLH) was strongly suspected and as the condition deteriorated, HLH therapy was initiated. Although the clinical condition improved, longstanding hemophagocytosis followed despite therapy. We found that the patient carries a rare monoallelic variant in autocrine motility factor receptor (AMFR), encoding a ubiquitin ligase involved in innate cytosolic DNA sensing and interferon (IFN) production through the cyclic GMP-AMP synthase-stimulator of IFN genes (cGAS-STING) pathway. Peripheral blood mononuclear cells (PBMCs) from the patient exhibited impaired signaling downstream of STING in response dsDNA and 2'3'-cGAMP, agonists of cGAS and STING, respectively, and fibroblasts from the patient showed impaired type I IFN responses and significantly increased VZV replication. Overexpression of the variant AMFR R594C resulted in decreased K27-linked STING ubiquitination compared to WT AMFR. Moreover, ImageStream technology revealed reduced STING trafficking from ER to Golgi in cells expressing the patient AMFR R594C variant. This was supported by a dose-dependent dominant negative effect of expression of the patient AMFR variant as measured by IFN-β reporter gene assay. Finally, lentiviral transduction with WT AMFR partially reconstituted 2'3'-cGAMP-induced STING-mediated signaling and ISG expression in patient PBMCs. This work links defective AMFR-STING signaling to severe VZV disease and hyperinflammation and suggests a direct role for cGAS-STING in the control of viral infections in humans. In conclusion, we describe a novel genetic etiology of severe VZV disease in childhood, also representing the first inborn error of immunity related to a defect in the cGAS-STING pathway.

[Hemophagocytic lymphohistiocytosis: A retrospective analysis of 66 patients]

CONTEXT

Hemophagocytic lymphohistiocytosis is a rare syndrome with a poor prognosis, characterized by an uncontrolled dysregulation of the immune system. The rarity of this disease makes it difficult to obtain large cohorts. In this study, we analyzed the data of 66 patients: the objective was to describe the epidemiological, clinical, biological and therapeutic characteristics and to compare our results with those already published.

METHODS

We conducted a retrospective study at the University Hospital of Montpellier from 2015 to 2021. Patients were included when the diagnosis of HLH was mentioned on the hospitalization report and when the HSCORE was higher than 50% (169). Prognostic analyses were performed by comparing the patients who died from HMH to those who didn't.

RESULTS

The mean age the 66 patients included was 49.2 years, 62% were men. The percentage of deaths was 45.9%. Lymphoma was the main etiology, followed by infections, then autoimmune/autoinflammatory diseases. Fever, splenomegaly, hepatomegaly and organ failure were the main clinical manifestations. Pancytopenia was present in 62% of cases. Ferritin, triglycerides, LDH and AST were highly increased. Advanced age, associated lymphoma, and the severity of cytopenias were linked to a poor prognosis.

DISCUSSION

The study of the clinico-biological, epidemiological and survival data of the patients in our cohort allowed us to confirm previously published data but also to discuss some of them.

Laboratory Features and Pathology of Cytokine Storm Syndromes

The laboratory diagnosis of cytokine storm syndromes (CSSs), i.e., hemophagocytic lymphohistiocytosis (HLH) and macrophage activation syndrome (MAS), is often challenging. The laboratory features using routinely available tests lack specificity, whereas confirmatory testing is available in only few laboratories in the United States. The disease mechanisms are still largely unclear, particularly in adults. In this chapter, the pathogenesis of CSSs, their associated laboratory findings, and recommended diagnostic strategies are reviewed.

Criteria for Cytokine Storm Syndromes

In the past two decades, there has been a great deal of work aimed to devise diagnostic guidelines, classification criteria, and diagnostic scores for cytokine storm syndromes (CSSs). The most notable effort has been the large-scale multinational study that led to the development of the 2016 classification criteria for macrophage activation syndrome (MAS) complicating systemic juvenile idiopathic arthritis (JIA). Future studies should scrutinize the validity of the proposed criteria, particularly in systemic JIA patients treated with biologics, in children with subtle or incomplete forms of MAS, and in patients with MAS complicating other rheumatologic disorders. More generic CSS criteria are also available but often lack sensitivity and specificity in a wide variety of patient populations and CSSs of different etiologies. The coronavirus disease 2019 (COVID-19)-related lung disease led to an evolution of the concept of a "cytokine storm." Emerging and unsolved challenges in the diagnosis of the different forms of CSSs highlight the need for diagnostic tools and well-established classification criteria to enable timely recognition and correct classification of patients.

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.

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.

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.

INSPIRED Symposium Part 3: Prevention and Management of Pediatric Chimeric Antigen Receptor T Cell-Associated Emergent Toxicities

Chimeric antigen receptor (CAR) T cell (CAR-T) therapy has emerged as a revolutionary cancer treatment modality, particularly in children and young adults with B cell malignancies. Through clinical trials and real-world experience, much has been learned about the unique toxicity profile of CAR-T therapy. The past decade brought advances in identifying risk factors for severe inflammatory toxicities, investigating preventive measures to mitigate these toxicities, and exploring novel strategies to manage refractory and newly described toxicities, infectious risks, and delayed effects, such as cytopenias. Although much progress has been made, areas needing further improvements remain. Limited guidance exists regarding initial administration of tocilizumab with or without steroids and the management of inflammatory toxicities refractory to these treatments. There has not been widespread adoption of preventive strategies to mitigate inflammation in patients at high risk of severe toxicities, particularly children. Additionally, the majority of research related to CAR-T toxicity prevention and management has focused on adult populations, with only a few pediatric-specific studies published to date. Given that children and young adults undergoing CAR-T therapy represent a unique population with different underlying disease processes, physiology, and tolerance of toxicities than adults, it is important that studies be conducted to evaluate acute, delayed, and long-term toxicities following CAR-T therapy in this younger age group. In this pediatric-focused review, we summarize key findings on CAR-T therapy-related toxicities over the past decade, highlight emergent CAR-T toxicities, and identify areas of greatest need for ongoing research.

Colorectal Carcinoma-An Anomalous Trigger of Adult Hemophagocytic Lymphohistiocytosis

Hemophagocytic lymphohistiocytosis (HLH) is a rare but often fatal condition characterized by a hyperinflammatory immune response leading to multiorgan failure. It is predominantly observed in the pediatric population and can be classified as familial or acquired HLH. The latter is more common in adults, often associated with malignancy, infection, or autoimmune diseases. Among acquired HLH cases, hematologic neoplasms account for the majority, with only a few isolated reports documenting solid neoplasms as the cause. Herein, we present a case of adult HLH associated with colorectal adenocarcinoma, which, to the best of our knowledge, is only the second reported case of HLH associated with this type of cancer.

Clinical characteristics of hemophagocytic lymphohistiocytosis

BACKGROUND

There is no specificity in the clinical presentation of hemophagocytic lymphohistiocytosis (HLH).

OBJECTIVE

To study some clinical, etiological, and prognostic features of HLH to improve the clinical understanding of the disease.

METHODS

Retrospective analysis of the clinical data of 125 patients with HLH admitted to our hospital from June 2015 to August 2021, including clinical characteristics, laboratory indicators, and survival period. Statistical analysis was performed from the overall group of study indicators, which included population, children, and adults.

RESULTS

In the whole population, sex, age, blood myoglobin, and NK cell ratio of M-HLH and non-M-HLH patients (P< 0.05), serum albumin, and direct bilirubin were independent correlates of M-HLH. In the pediatric group, age and the proportion of NK cells were significantly different between M-HLH and non-M-HLH patients (P< 0.05). Multivariate Logistic regression analysis showed that all factors were not significantly associated with M-HLH. The associated regression analysis showed that all factors were not significantly associated with M-HLH. ROC curve analysis showed that the best predictive value of NK cell percentage for M-HLH diagnosis in the overall population was 4.96% in the pediatric group and 4.96% in the adult group. The best predictive value for M-HLH diagnosis was 2.08%. The univariate analysis showed that platelet count, alanine aminotransferase, aspartate aminotransferase, serum albumin, direct bilirubin and indirect bilirubin affected prognosis; COX regression showed that none of these factors had a significant relationship. The overall median survival time was 20.7 months in the adult group, 44.3 months in non-M-HLH patients, and 7.73 months in M-HLH patients (p= 0.011); univariate analysis showed that platelet count and serum albumin level affected prognosis; COX regression results in serum albumin level was an independent risk factor for prognosis.

CONCLUSION

The survival rate of non-M-HLH was significantly better than that of M-HLH; the proportion of NK cells had predictive value for the diagnosis of M-HLH; in the general population, non-M-HLH was more likely to have abnormal liver function than M-HLH: lower platelet count and serum albumin level were associated with poor prognosis, and the lower the platelet count and serum albumin level, the worse the prognosis: in addition, adults with lower serum albumin levels are also associated with poor prognosis.

Hemophagocytic Lymphohistiocytosis in the Context of Hematological Malignancies and Solid Tumors

Hemophagocytic lymphohistiocytosis (HLH) has been described for decades in association with malignancies (M-HLH). While its mechanism is unknown, M-HLH has a poor prognosis, ranging from 10% to 30% overall survival. Mature T-cell lymphomas, diffuse large B-cell lymphoma, and Hodgkin lymphoma, with or without viral co-triggers such as Epstein-Barr virus, are among the most frequent underlying entities. Most M-HLH cases occur at the presentation of malignancy, but they may also occur during therapy as a result of immune compromise from chemotherapy (HLH in the context of immune compromise, IC-HLH) and (typically) disordered response to infection or after immune-activating therapies (Rx-HLH, also known as cytokine release syndrome, CRS). IC-HLH typically occurs months after diagnosis in the context of fungal, bacterial, or viral infection, though it may occur without an apparent trigger. Rx-HLH can be associated with checkpoint blockade, chimeric antigen receptor T-cell therapy, or bispecific T-cell engaging therapy. Until recently, M-HLH diagnosis and treatment strategies were extrapolated from familial HLH (F-HLH), though optimized diagnostic and therapeutic treatment strategies are emerging.

Etoposide Therapy of Cytokine Storm Syndromes

Etoposide has revolutionized the treatment of primary as well as secondary hemophagocytic lymphohistiocytosis (HLH), and it is, together with corticosteroids, the most widely used therapy for HLH. In the early 1980s, long-term survival in primary HLH was <5% but with the etoposide-/dexamethasone-based protocols HLH-94 and HLH-2004, in combination with stem cell transplantation, 5-year survival increased dramatically to around 60% in primary HLH, and based on analyses from the HLH-2004 study, there is likely room for further improvement. Biologically, etoposide administration results in potent selective deletion of activated T cells as well as efficient suppression of inflammatory cytokine production. Moreover, etoposide has also been reported to promote programmed cell death (apoptosis) rather than proinflammatory lytic cell death (pyroptosis), conceivably ameliorating subsequent systemic inflammation, i.e., a treatment very suitable for cytokine storm syndromes (CSS). The combination of etoposide and corticosteroids may also be beneficial in cases of severe or refractory secondary HLH (sHLH) with imminent organ failure, such as infection-associated HLH caused by Epstein-Barr virus (EBV) or malignancy-triggered HLH. In CSS associated with rheumatic diseases (macrophage activation syndrome, MAS or MAS-HLH), etoposide is currently used as second- or third-line therapy. Recent studies suggest that etoposide perhaps should be part of an aggressive therapeutic intervention for patients with severe refractory or relapsing MAS, in particular if there is CNS involvement. Importantly, awareness of sHLH must be further increased since treatment of sHLH is often delayed, thereby missing the window of opportunity for a timely, effective, and potentially life-saving HLH-directed treatment.

A fatal case of hemophagocytic lymphohistiocytosis due to neonatal lupus erythematosus

Neonatal lupus erythematosus (NLE) is an autoimmune disease caused by the passive transfer of autoantibodies from mother to child during pregnancy. A rare complication of NLE is hemophagocytic lymphohistiocytosis (HLH), a potentially life-threatening hyperinflammatory state more commonly associated with other rheumatologic disorders. Herein, we describe a fatal case of NLE-associated HLH.

Inpatient recognition and management of HLH

Hemophagocytic lymphohistiocytosis (HLH) is one of the life-threatening emergencies that a hematologist may be called upon to diagnose and manage. It is a hyperinflammatory process that develops in patients with genetic abnormalities, hematologic malignancies, chronic inflammatory states, or infections. The main clinical challenges are recognizing HLH, determining whether the immune response is aberrant or appropriate, and deciding upon therapy. Patients may present with fever, central nervous system symptoms, cytopenias, or elevated liver enzymes. Recognizing HLH is challenging because its features overlap with numerous systemic disorders, thus requiring a high level of suspicion and timely investigations to confirm the diagnosis and detect the underlying trigger. Once HLH is diagnosed, careful consideration of immunosuppressive therapy's potential benefit versus harm is necessary. Such therapy can sometimes be tailored to the underlying trigger. In the acute setting, the competing pressures of completing a thorough diagnostic process (including evaluation for the presence of lymphoma and infection) and the need for expedited treatment must be balanced. During the management of an HLH patient, continuous vigilance for the presence of as-yet unrecognized disease triggers, monitoring response, and identifying emerging complications is critical. This review will discuss the recognition and management of HLH in the inpatient setting.

Inflamed-HLH, MAS, or something else?

Hemophagocytic lymphohistiocytosis (HLH) is a syndrome of excessive and maladaptive inflammation. Primary HLH is most frequently encountered in young children, and, without timely recognition and therapy, can lead to multiorgan failure and death. It is most often diagnosed using the HLH-2004 criteria and by identifying pathological mutations. However, the HLH-2004 criteria are not specific for HLH, and patients can easily fulfill these diagnostic criteria in other proinflammatory states in which HLH-therapy would not be indicated, including hematologic malignancies, infections, and rheumatologic disease. Therefore, great care must be taken to ensure that the specific disease associated with features of HLH is accurately recognized, as consequences of improper treatment can be catastrophic. We propose a diagnostic pathway for patients for whom HLH is on the differential (visual abstract). Importantly, in situations in which the initial diagnostic workup is equivocal or unrevealing, reevaluation for occult malignancy, infection, or rheumatologic disease would be prudent, as occult presentations may be missed on primary evaluation. Temporizing medications can be used in critically ill patients while awaiting secondary evaluation. By using this framework, clinicians will be able to more reliably discern primary HLH from other pro-inflammatory states and thus provide timely, appropriate disease-specific therapy.

Where have all the platelets gone? HIT, DIC, or something else?

Thrombocytopenia in ill children is common; accurately diagnosing the underlying etiology is challenging and essential for appropriate management. Triggers for accelerated consumption of platelets are numerous; common downstream mechanisms of clearance include platelet trapping in microvascular thrombi, phagocytosis, and platelet activation. Thrombocytopenia with microangiopathic hemolytic anemia (MAHA) is frequently due to disseminated intravascular coagulation. Thrombotic microangiopathy (TMA) is a subgroup of MAHA. Specific TMA syndromes include thrombotic thrombocytopenic purpura, complement-mediated TMA (CM-TMA), and Shiga toxin-mediated hemolytic uremic syndrome. Isolated thrombocytopenia is characteristic of immune thrombocytopenia; however, concomitant cytopenias are frequent in critically ill patients, making the diagnosis difficult. Immune thrombocytopenia with large vessel thrombosis is a feature of heparin-induced thrombocytopenia and antiphospholipid antibody syndrome. In addition, thrombocytopenia is common with macrophage activation, which is characteristic of hemophagocytic lymphohistiocytosis. While thrombocytopenia in ill patients can be driven by hypoproliferative processes such as myelosuppression and/or bone marrow failure, this review will focus on consumptive thrombocytopenia due to immune and nonimmune causes.

Hemophagocytic lymphohistiocytosis with jaundice as first manifestation: A case report

BACKGROUND

Hemophagocytic lymphohistiocytosis (HLH) is a rare but life-threatening condition. It is an immune-mediated disease that has a wide range of causes, elicits a hyperinflammatory response, and results in multiple organ damage. Clinical presentations vary, and in some cases, jaundice occurs as the first symptom.

CASE SUMMARY

We report the case of a 71-year-old female patient who presented with jaundice. She was admitted to our hospital because of the occurrence of "jaundice for half a month", and upon examination, obstructive jaundice with choledocholithiasis and gallstones was suggested. Cholecystectomy and choledocholithotomy were performed. However, the jaundice did not improve after surgery. We found splenomegaly, cytopenia, hypertriglyceridemia, hypofibrinogenemia, and elevated ferritin. Bone marrow biopsy revealed hemophagocytosis. Later, cardiac arrest occurred when she returned 3 wk after the surgery. We considered that HLH was triggered by septic shock. The patient's condition deteriorated rapidly, with multiple organ dysfunction and severe gastrointestinal bleeding. Corticosteroid therapy and symptomatic treatment failed to save her life.

CONCLUSION

Jaundice rarely presents as the first symptom in HLH patients. The HLH in this case was triggered by septic shock with jaundice as the first symptom. Clinicians should try hard to reduce missed diagnoses and misdiagnoses.

Elevated monocyte HLA-DR in pediatric secondary hemophagocytic lymphohistiocytosis: a retrospective study

Introduction

Hemophagocytic lymphohistiocytosis (HLH) is a life-threatening condition, and its diagnosis may be challenging. In particular, some cases show close similarities to sepsis (fever, organ failure, and high ferritin), but their treatment, while urgent, differ: prompt broad-spectrum antibiotherapy for sepsis and immunosuppressive treatment for HLH. We questioned whether monocyte human leucocyte antigen (mHLA)-DR could be a diagnostic marker for secondary HLH (sHLH).

Methods

We retrospectively reviewed data from patients with a sHLH diagnosis and mHLA-DR quantification. mHLA-DR data from healthy children and children with septic shock, whose HLA-DR expression is reduced, from a previously published study were also included for comparison.

Results

Six patients with sHLH had mHLA-DR quantification. The median level of monocyte mHLA-DR expression in patients with sHLH [79,409 antibodies bound per cell (AB/C), interquartile range (IQR) (75,734-86,453)] was significantly higher than that in healthy children and those with septic shock (29,668 AB/C, IQR (24,335-39,199), and 7,493 AB/C, IQR (3,758-14,659), respectively). Each patient with sHLH had a mHLA-DR higher than our laboratory normal values. Four patients had a second mHLA-DR sampling 2 to 4 days after the initial analysis and treatment initiation with high-dose corticosteroids; for all patients, mHLA-DR decreased to within or close to the normal range. One patient with systemic juvenile idiopathic arthritis had repeated mHLA-DR measurements over a 200-day period during which she underwent four HLH episodes. mHLA-DR increased during relapses and normalized after treatment incrementation.

Conclusion

In this small series, mHLA-DR was systematically elevated in patients with sHLH. Elevated mHLA-DR could contribute to sHLH diagnosis and help earlier distinction with septic shock.

Hemophagocytic lymphohistiocytosis with a hemizygous PRF1 c.674G>A mutation

Hemophagocytic lymphohistiocytosis(HLH) is a rare highly-fatal disease presenting with fever, hepatosplenomegaly, and pancytopenia and has a poor prognosis. Homozygous or semi-zygous or complex heterozygous variants can cause familial HLH and heterozygous carriers are frequently seen in secondary HLH. A 42-year-old male patient was admitted to the hospital for persistent fever, fatigue, and splenomegaly. Investigations revealed hypertriglyceridemia, hyperlactatemia dehydrogenaseemia, hyperferritinemia, and elevated levels of soluble cluster of differentiation 25. We found a heterozygous mutation of PRF1: c.674G>A (p.R225Q) through next-generation sequencing technology of hemophagocytic-lymphohistiocytosis-related genes. After a brief remission with dexamethasone and etoposide-based therapy, the disease relapsed quickly, and an allogeneic hematopoietic stem cell transplant was performed to achieve complete remission. To date, the patient's condition was in complete remission. Our study detected a rare missense mutation in the PRF1 gene in a patient with HLH disease and the c.674G>A mutation may be rated as a possible pathogenic variant.

A distinct cytokine network distinguishes chimeric antigen receptor T cell (CAR-T)-associated hemophagocytic lymphohistiocytosis-like toxicity (carHLH) from severe cytokine release syndrome following CAR-T therapy

BACKGROUND AIMS

With the increasing application of chimeric antigen receptor (CAR)-T cell therapy in various malignancies, an extra toxicity profile has been revealed, including a severe complication resembling hemophagocytic lymphohistiocytosis (HLH), which is usually disguised by severe cytokine release syndrome (CRS).

METHODS

In a clinical trial in whom 99 patients received B-cell maturation antigen CAR-T cells, we identified 20 (20.20%) cases of CAR-T cell-associated HLH (carHLH), most of whom possessed a background of severe CRS (grade ≥3). The overlapping features of carHLH and severe CRS attracted us to further explore the differences between them.

RESULTS

We showed that carHLH can be distinguished by extreme elevation of interferon-γ, granzyme B, interleukin-1RA and interleukin-10, which can be informative in developing prevention and management strategies of this toxicity. Moreover, we developed a predictive model of carHLH with a mean area under the curve of 0.81 ± 0.07, incorporating serum lactate dehydrogenase at day 6 post-CRS and serum fibrinogen at day 3 post-CRS.

CONCLUSIONS

The incidence of carHLH in CAR-T recipients might be relatively higher than we previously thought. relatively higher than we previously. A cytokine network distinguished from CRS is responsible for carHLH. And corresponding cytokine-directed therapies, especially targeting IL-10, are worth trying.

The 2022 EULAR/ACR Points to Consider at the Early Stages of Diagnosis and Management of Suspected Haemophagocytic Lymphohistiocytosis/Macrophage Activation Syndrome (HLH/MAS)

OBJECTIVE

Haemophagocytic lymphohistiocytosis (HLH) and macrophage activation syndrome (MAS) are life-threatening systemic hyperinflammatory syndromes that can develop in most inflammatory contexts. They can progress rapidly, and early identification and management are critical for preventing organ failure and mortality. This effort aimed to develop evidence-based and consensus-based points to consider to assist clinicians in optimising decision-making in the early stages of diagnosis, treatment and monitoring of HLH/MAS.

METHODS

A multinational, multidisciplinary task force of physician experts, including adult and paediatric rheumatologists, haematologist/oncologists, immunologists, infectious disease specialists, intensivists, allied healthcare professionals and patients/parents, formulated relevant research questions and conducted a systematic literature review (SLR). Delphi methodology, informed by SLR results and questionnaires of experts, was used to generate statements aimed at assisting early decision-making and optimising the initial care of patients with HLH/MAS.

RESULTS

The task force developed 6 overarching statements and 24 specific points to consider relevant to early recognition of HLH/MAS, diagnostic approaches, initial management and monitoring of HLH/MAS. Major themes included the simultaneous need for prompt syndrome recognition, systematic evaluation of underlying contributors, early intervention targeting both hyperinflammation and likely contributors, careful monitoring for progression/complications and expert multidisciplinary assistance.

CONCLUSION

These 2022 EULAR/American College of Rheumatology points to consider provide up-to-date guidance, based on the best available published data and expert opinion. They are meant to help guide the initial evaluation, management and monitoring of patients with HLH/MAS in order to halt disease progression and prevent life-threatening immunopathology.

Implementing a Disease-specific Multidisciplinary Team and Order Set for Hemophagocytic Lymphohistiocytosis in a Pediatric Hospital

OBJECTIVE

To improve outcomes of hemophagocytic lymphohistiocytosis (HLH), prompt recognition and treatment are necessary. A HLH multidisciplinary team was implemented at our institution, and we established an electronic order set to foster uniformity in the diagnostic approach. The goal of this study is to capture the impact of this diagnostic tool.

METHODS

This is a retrospective study analyzing the utilization of a HLH-specific order set since time of implementation in June 2019 through December 2022. The trends in the utilization of the order set by providers were analyzed to evaluate the awareness and effectiveness of this tool.

RESULTS

The order set was utilized 50 times, most commonly by hematology/oncology (50%) and infectious disease (26%). Utilization by providers on newly presenting patients included 4 times in the year 2019, 12 times in 2020, 16 times in 2021, and 18 times in 2022. Utilization was associated with the diagnosis of HLH in 9 patients (18%).

CONCLUSION

Implementation of an HLH-specific order set facilitated a systematic method to approach patients with suspected HLH. The utilization of the order set displayed an upward trend over time, indicating support of this tool among these providers. This tool can increase awareness and early identification of HLH.

The 2022 EULAR/ACR points to consider at the early stages of diagnosis and management of suspected haemophagocytic lymphohistiocytosis/macrophage activation syndrome (HLH/MAS)

OBJECTIVE

Haemophagocytic lymphohistiocytosis (HLH) and macrophage activation syndrome (MAS) are life-threatening systemic hyperinflammatory syndromes that can develop in most inflammatory contexts. They can progress rapidly, and early identification and management are critical for preventing organ failure and mortality. This effort aimed to develop evidence-based and consensus-based points to consider to assist clinicians in optimising decision-making in the early stages of diagnosis, treatment and monitoring of HLH/MAS.

METHODS

A multinational, multidisciplinary task force of physician experts, including adult and paediatric rheumatologists, haematologist/oncologists, immunologists, infectious disease specialists, intensivists, allied healthcare professionals and patients/parents, formulated relevant research questions and conducted a systematic literature review (SLR). Delphi methodology, informed by SLR results and questionnaires of experts, was used to generate statements aimed at assisting early decision-making and optimising the initial care of patients with HLH/MAS.

RESULTS

The task force developed 6 overarching statements and 24 specific points to consider relevant to early recognition of HLH/MAS, diagnostic approaches, initial management and monitoring of HLH/MAS. Major themes included the simultaneous need for prompt syndrome recognition, systematic evaluation of underlying contributors, early intervention targeting both hyperinflammation and likely contributors, careful monitoring for progression/complications and expert multidisciplinary assistance.

CONCLUSION

These 2022 EULAR/American College of Rheumatology points to consider provide up-to-date guidance, based on the best available published data and expert opinion. They are meant to help guide the initial evaluation, management and monitoring of patients with HLH/MAS in order to halt disease progression and prevent life-threatening immunopathology.

Hemophagocytic lymphohistiocytosis: A scourge for the physician and bane to the bone marrow

Background

Hemophagocytic lymphohistiocytosis (HLH) is a condition characterized by hyperinflammation. It can occur due to primary genetic defect or secondary to other etiology such as infection and rheumatological conditions. Clinical features include fever, cytopenia, organomegaly and several laboratory abnormalities. It can be a life-threatening condition secondary to worsening cytopenia and multiorgan dysfunction.

Aims and Objectives

To study the clinical profile of HLH in a tertiary care hospital in Southern India.

Materials and Methods

Our study has reviewed nine cases of HLH among adult patients presented over 5 years (2017-2022).

Results

The majority of our cases were secondary to infection and had a hospital stay over two weeks and with a good response to steroid and immunomodulators.

Conclusion

We would like to stress upon the importance of awareness of such a condition so that there can be early suspicion and workup including bone marrow examination, enabling early initiating of specific therapy for this fatal condition.

Postpartum hemophagocytic lymphohistiocytosis: A case report

BACKGROUND

Postpartum hemophagocytic lymphohistiocytosis (HLH) is a rare disease with unclear pathophysiology. It is a secondary HLH diagnosed using the pediatric diagnostic criteria; however, the clinical diagnosis of postpartum HLH remains challenging. Hence, HLH may remain undiagnosed, leading to poor patient prognosis. Therefore, improvements in the accuracy of postpartum HLH diagnoses and treatments are necessary.

CASE SUMMARY

We report the case of a 40-year-old female with postpartum HLH. The patient attended the postpartum care center for 3 wk after giving birth and underwent needle aspiration due to thyroid gland enlargement 11 d before an emergency department visit precipitated by fever and abdominal pain. Since no abnormal emergency room findings were noted, the patient was discharged with a prescription for broad-spectrum antibiotics. Three days later, she returned to the emergency room in a hemodynamically unstable state and was admitted to the intensive care unit with suspected sepsis or hematologic disease. The patient was treated, without effect, for sepsis using broad-spectrum antibiotics, and for suspected hematologic disease with steroid therapy. However, she died due to rapidly worsening symptoms.

CONCLUSION

Rapid recognition and appropriate treatment of postpartum HLH are needed to improve the prognosis.

Secondary hemophagocytic lymphohistiocytosis in children (Review)

Hemophagocytic lymphohistiocytosis (HLH) is a rare, life-threatening condition characterized by hyperinflammation in an uncontrolled and ineffective immune response. Despite great improvement in diagnosis and treatment, it still represents a challenge in clinical management, with poor prognosis in the absence of an aggressive therapeutic approach. The present literature review focuses on secondary HLH at pediatric age, which represents a heterogeneous group in terms of etiology and therapeutic approach. It summarizes the most recent evidence on epidemiology, pathophysiology, diagnosis, treatment and prognosis, and provides a detailed description and comparison of the major subtypes of secondary HLH. Finally, it addresses the open questions with a focus on diagnosis and new treatment insights.

Sepsis as the Grand Mimic of Secondary Hemophagocytic Lymphohistiocytosis: Serratia marcescens Bacteremia with Concomitant Decompensated Cirrhotic Liver Disease

Secondary hemophagocytic lymphohistiocytosis (HLH) is an elusive entity with sequelae that may be confused with sepsis. We discuss a 45-year-old man with decompensated liver cirrhosis with sepsis treated with broad-spectrum intravenous antibiotics. Further work-up initially supported sepsis-HLH overlap syndrome (SHLHOS) and corticosteroids were added. Ongoing refractory hypotension ensued, and the patient passed within 31 hours of presentation. Based on the patient's overwhelming immune activation and clinical course likely unsalvageable by cytotoxic immunosuppressive agents, the patient was diagnosed with sepsis with acute end organ dysfunction. This case report illustrates both the diagnostic challenge of sepsis versus HLH, which both require very different treatments, and the potential for rapid clinical decline without swift recognition and management of the true pathology.

Tuberculosis-Associated Hemophagocytic Lymphohistiocytosis: A Review of Current Literature

Hemophagocytic lymphohistiocytosis (HLH) is a condition of immune dysregulation and hyperinflammation, leading to organ failure and death. Malignancy, autoimmune conditions, and infections, including Mycobacterium tuberculosis (TB), are all considered triggers of HLH. The aim of this study was to review all reported cases of TB-associated HLH in English literature, and to summarize the epidemiology, diagnostics, treatment, and mortality in patients with concomitant HLH and TB. A systematic review of described cases with TB-associated HLH, via a structured literature search in the medical database PubMed, is presented. Additional articles were included through cross-referencing with existing review articles. Articles were reviewed based on a predetermined set of criteria. A total of 116 patients with TB-associated HLH were identified with a male:female ratio of about 3:2. The age at presentation ranged from 12 days to 83 years. Malignancy, autoimmunity, and renal failure were the most common comorbid conditions. Most patients received both tuberculostatic and specific immunomodulating treatment, which was associated with a 66% (48/73) survival rate compared to 56% (15/27) in those receiving only tuberculostatic treatment, and 0% (0/13) in those receiving only immunomodulating treatment. The survival rate was 55% overall. The overlapping presentation between disseminated TB and HLH poses challenging diagnostics and may delay diagnosis and treatment, leading to increased mortality. TB should be considered as a potential trigger of HLH; clinicians' knowledge and awareness of this may result in the appropriate investigations needed to ensure diagnosis and proper treatment.

First LIPA Mutational Analysis in Egyptian Patients Reveals One Novel Variant: Wolman Disease

Lysosomal acid lipase (LAL) is a necessary enzyme for the hydrolysis of both triglycerides (TGs) and cholesteryl esters (CEs) in the lysosome. Deficiency of this enzyme encoded by the lipase A (LIPA) gene leads to LAL deficiency (LAL-D). A severe disease subtype of LAL-D is known as Wolman disease (WD), present with diarrhea, hepatosplenomegaly, and adrenal calcification. Untreated patients do not survive more than a year. The aim of this study was to assess the clinical and molecular characterizations of WD patients in Egypt. A total of seven patients (from five unrelated Egyptian families) were screened by targeted next-generation sequencing (NGS), and the co-segregation of causative variants was analyzed using Sanger sequencing. Furthermore, multiple in silico analyses were performed to assess the pathogenicity of the candidate variants. Overall, we identified three diseases causing variants harbored in the LIPA gene. One of these variants is a novel missense variant (NM_000235.4: c.1122 T > G; p. His374Gln), which was classified as a likely pathogenic variant. All variants were predicted to be disease causing using in silico analyses. Our findings expand the spectrum of variants involved in WD which may help to investigate phenotype-genotype correlation and assist genetic counseling. To the best of our knowledge, this is the first clinico-genetic study carried out on Egyptian patients affected with WD.

Immune Effector Cell-Associated Hemophagocytic Lymphohistiocytosis-Like Syndrome

T cell-mediated hyperinflammatory responses, such as cytokine release syndrome (CRS) and immune effector cell-associated neurotoxicity syndrome (ICANS), are now well-established toxicities of chimeric antigen receptor (CAR) T cell therapy. As the field of CAR T cells advances, however, there is increasing recognition that hemophagocytic lymphohistiocytosis (HLH)-like toxicities following CAR T cell infusion are occurring broadly across patient populations and CAR T cell constructs. Importantly, these HLH-like toxicities are often not as directly associated with CRS and/or its severity as initially described. This emergent toxicity, however ill-defined, is associated with life-threatening complications, creating an urgent need for improved identification and optimal management. With the goal of improving patient outcomes and formulating a framework to characterize and study this HLH-like syndrome, we established an American Society for Transplantation and Cellular Therapy panel composed of experts in primary and secondary HLH, pediatric and adult HLH, infectious disease, rheumatology and hematology, oncology, and cellular therapy. Through this effort, we provide an overview of the underlying biology of classical primary and secondary HLH, explore its relationship with similar manifestations following CAR T cell infusions, and propose the term "immune effector cell-associated HLH-like syndrome (IEC-HS)" to describe this emergent toxicity. We also delineate a framework for identifying IEC-HS and put forward a grading schema that can be used to assess severity and facilitate cross-trial comparisons. Additionally, given the critical need to optimize outcomes for patients experiencing IEC-HS, we provide insight into potential treatment approaches and strategies to optimize supportive care and delineate alternate etiologies that should be considered in a patient presenting with IEC-HS. By collectively defining IEC-HS as a hyperinflammatory toxicity, we can now embark on further study of the pathophysiology underlying this toxicity profile and make strides toward a more comprehensive assessment and treatment approach.

Secondary hemophagocytic lymphohistiocytosis: an unusual complication in disseminated Mycobacterium tuberculosis

Tuberculosis-associated hemophagocytic lymphohistiocytosis (TB-HLH) is a rare and life-threatening complication of tuberculosis infection. Early recognition and treatment of TB-HLH is crucial for improving outcomes. Treatment typically involves a combination of antituberculosis therapy and immunosuppressive therapy to control the immune system's overreaction. In this report, we present the case of a 53-year-old ambulance driver who was diagnosed with TB-HLH. His CT scan revealed splenic abscesses, hepatomegaly and bilateral lung consolidation. He subsequently developed multiorgan failure, including acute respiratory distress syndrome (ARDS), transaminitis and bone marrow dysfunction. The clinical course and simultaneous increase in serum ferritin raised the suspicion of HLH. His Hscore was 254, indicating a high probability of hemophagocytic syndrome. TB diagnosis was confirmed by positive endotracheal TB GeneXpert and bone marrow aspiration (BMA) which detected acid-fast bacilli organisms. The patient was promptly started on anti-TB, dexamethasone and IVIG. The patient responded well to treatment and made a full recovery without any lasting complications. This case highlights the importance of promptly recognising HLH and identifying the underlying cause. In critically ill patients, it is crucial not to delay HLH-specific treatment while working up for differential diagnosis.

Approaching hemophagocytic lymphohistiocytosis

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

Hemophagocytic Lymphohistiocytosis in a Patient with Hodgkin Lymphoma, HIV, and Epstein-Barr Virus

Hemophagocytic lymphohistiocytosis (HLH) is an aggressive and life-threatening syndrome of excessive immune activation. It occurs in many underlying conditions and all age groups due to severe and uncontrolled inflammatory reactions, with the resultant overproduction of immune cells and cytokines. This leads to multi-organ damage (if not detected early and treated properly) with a mortality of more than 55%. We present a case of a 38-year-old male patient who presented with HLH with concurrent HIV/AIDS, and Epstein-Barr virus (EBV)-related Hodgkin lymphoma. We aim to emphasize the importance of considering HLH and cancer in patients with HIV/AIDS.

Serum sCD25/ferritin ratio combined with MCP-1 is a valid predictor for identifying LAHS with HLH as the first manifestation

PURPOSE

Lymphoma-associated haemophagocytic syndrome (LAHS) is a group of malignant diseases with rapid progression and a high mortality rate. Our study aimed to discover the significance of serum sCD25/ferritin ratio as well as cytokines in assisting the diagnosis of LAHS.

METHODS

We retrospectively analyzed the clinical data of 82 patients with LAHS with hemophagocytic lymphohistiocytosis (HLH) as the first manifestation and divided them into B-LAHS group and T/NK-LAHS group according to lymphoma pathological diagnosis for comparison. And patients with LAHS were divided into responding group, non-responding group according to the assessment of efficacy after receiving DEP/L-DEP induction therapy for 2 weeks to compare possible valuable indicators.

RESULTS

Serum sCD25/ferritin ratio and MCP-1 levels were significantly different between B-LAHS and T/NK-LAHS groups (P = 0.001, P = 0.022). An sCD25/ferritin ratio > 7.8 tended to suggest a diagnosis of B-LAHS (AUC = 0.71, 95% CI: 0.596-0.823), and the sCD25/ferritin ratio had better predictive value when combined with MCP-1 (AUC = 0.81, 95% CI: 0.699-0.922). The sCD25/ferritin ratio was also significantly different between the two groups responding or not responding to induction therapy (P = 0.002), yielding an optimal cutoff value of 11.48. An sCD25/ferritin ratio > 11.48 tended to suggest that the patient's LAHS was responsive to induction therapy.

CONCLUSION

Our study reveals that serum sCD25/ferritin ratio combined with MCP-1 is a valid predictor for identifying LAHS with HLH as the first manifestation and may assist in predicting whether the lymphoma is of B-cell or T/NK-cell origin. The sCD25/ferritin ratio can also be used to predict the early response of LAHS after induction therapy.

Hemophagocytic lymphohistiocytosis in inflammatory bowel disease: a nationwide analysis

Hemophagocytic lymphohistiocytosis (HLH) is a rare but life-threatening immune dysregulation disease. Patients with inflammatory bowel disease (IBD) can become profoundly immunocompromised due to immunosuppressive therapy, hence increasing the risk of viral infections that can trigger HLH. However, data on the association between IBD and HLH remains limited. We used data from the National Inpatient Sample (2012-2019) utilizing International Classification of Diseases (ICD)-9 or ICD-10 codes to identify individuals with IBD, either Crohn's disease (CD) or ulcerative colitis (UC), and HLH. The primary outcome was to compare the prevalence of HLH among patients with IBD with those without IBD. Secondary outcomes included in-hospital mortality, mean hospital length of stay, and description of HLH-associated triggers in IBD patients. A total of 513,322 hospitalizations included a diagnosis of IBD, 188,297 had UC and 325,025 had CD. Compared to the general population, patients with IBD were older (median age of 52 vs. 49 years, p < 0.05), more likely to be male, and of Asian/Pacific Islander descent, and had a higher median household income. There was also a higher prevalence of liver disease, autoimmune diseases, tobacco abuse, and hypothyroidism (all had p-value of < 0.001) in IBD patients. There were 94 hospitalizations identified with a diagnosis of HLH in IBD patients. Compared to patients without IBD, patients with IBD had increased odds of developing HLH (0.02% vs 0.01%, p-value < 0.001). After adjusting for various demographic characteristics, co-morbidities, and HLH-related conditions, IBD was an independent predictor for developing HLH (adjusted OR, 2.3; 95% CI, 1.847-2.866, p-value of < 0.001). There was no statistical difference between CD and UC in the odds of developing HLH. Compared to IBD patients without HLH, patients with IBD and HLH had a lower mean age at diagnosis (38 vs 52, p-value of < 0.001), higher in-hospital mortality (14.9% vs 1.5%, p-value of < 0.001), and longer mean hospital length of stay (days) (17 vs 5.4, p-value of < 0.001). Prevalence of different HLH-associated illnesses was identified in HLH patient's discharge data. Lymphoma was the most common associated malignancy (18.1%) and cytomegalovirus infection was the most common associated infection (16.0%). Our population-based study suggests that IBD is independently associated with developing HLH. Early recognition of IBD patients presenting with features suggestive of HLH is warranted to aide early diagnosis and aggressive treatment.

Cutaneous granuloma annulare in an adult patient with macrophage activation syndrome

Macrophage activation syndrome (MAS) is a rare but life-threatening disorder that is associated with multiple organ involvement. Here, we described cutaneous granuloma annulare in MAS. This novel histological finding is a reminder to explore the underlying mechanisms of skin involvement in MAS, which may reveal its pathogenesis.

Serum cytokine pattern in children with hemophagocytic lymphohistiocytosis

This study aimed to compare the serum levels of 34 cytokines of children with hemophagocytic lymphohistiocytosis (HLH) and explored the specific cytokine pattern of HLH subtypes and the relationship between cytokine levels and prognosis. This retrospective study assessed the clinical data and cytokine levels of newly diagnosed children with HLH in Beijing Children's Hospital, Capital Medical University, from January 2017 to December 2021. A total of 101 children were enrolled in the study. The levels of IFN-γ and IL-18 increased in more than 90% of patients, and MIP-1α, SDF-1α, IP-10, IL-6, IL-8, IL-10, IL-1 RA, and TNF-α increased at different levels in more than 50% of patients. The levels of IL-10 in EBV-HLH increased significantly, followed by IFN-γ and IL-18, while IL-10 and IFN-γ in CAEBV-HLH had a slight increase. Except for IL-10, the levels of IL-6, Eotaxin, IL-13, IL-18, IFN-γ, and MIP-1β in Rh-HLH increased significantly. F-HLH had significantly high IL-10 levels and a slight increase in IL-13. We showed that various cytokines could assist in differentiating HLH subtypes with ROC curve analysis. When IL-10/IL-6 was 1.37, the sensitivity and specificity of diagnosing EBV-HLH were higher than 80% (AUC = 0.837, p < 0.001). The effect of cytokine ratio on classifying HLH subtypes (17/22, 77.3%) was more significant than the single cytokine (5/22, 22.7%). The 3-year overall survival (OS) rate of children with F-HLH was the lowest during the follow-up. The 3-year OS of patients with EBV-HLH and CAEBV-HLH was significantly higher than that with F-HLH (88.1% ± 5.0% vs. 94.1% ± 5.7% vs. 57.1% ± 14.6%, p = 0.017). Cox proportional hazards model revealed that elevated GM-CSF and MCP-1, as well as CNS involvement, were independent risk factors for poor outcomes for patients with HLH. Various cytokines play important roles in HLH. Different subtypes of HLH have their specific cytokines pattern, and the ratio of cytokines may be more significant in differentiating HLH subtypes than the single one. Elevated GM-CSF and MCP-1 could be useful biomarkers for a poor prognosis for patients with HLH.

Disseminated tuberculosis in rare association with hemophagocytic lymphocytosis - A case report from central India

Hemophagocytic Lymphohistiocytosis (HLH) is an uncommon, diverse and rare genetic hyper-inflammatory syndrome. HLH associated with tuberculosis (TB-HLH) has been described as a clinical and diagnostic quandary. The co-existence leads to significantly higher morbidity and mortality. Our case highlights the presence of disseminated tuberculosis and worsening of the case due to underlying hemophagocytic syndrome leading to rapid deterioration of patient prognosis. Prompt diagnosis and treatment remains help to improve patient management.

Hemophagocytic Lymphohistiocytosis Masquerading as Autoimmune Hepatitis

Hemophagocytic lymphohistiocytosis (HLH) is a complex disease disorder that involves dysregulated activation of the immune system resulting in cytokine storm which can lead to widespread tissue injury. HLH is associated with a mortality rate of 41%. The diagnosis of HLH requires a median of 14 days to reach likely due to a varied range of symptoms and signs the disease can present with. Liver disease and HLH can have a significant overlap. Liver injury itself is frequently noticed in patients with HLH, with more than 50% of patients having elevated aspartate transaminase, alanine transaminase, and bilirubin levels. This case report describes a young individual who had developed intermittent fever, vomiting, fatigue, and weight loss with labs remarkable for elevated transaminases and bilirubin. His initial workup revealed an acute Epstein-Barr virus infection. The patient later presented again with similar signs and symptoms. He underwent a liver biopsy with histopathological features initially concerning for autoimmune hepatitis. However, by engaging a multidisciplinary team, a correct diagnosis was achieved. This case report serves to highlight the increased level of suspicion required to correctly diagnose HLH, especially in the presence of clinical features concerning for autoimmune hepatitis.

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.

Population pharmacokinetics of ruxolitinib in children with hemophagocytic lymphohistiocytosis: focus on the drug-drug interactions

PURPOSE

The optimal dose regimen of ruxolitinib (RUX) in children with hemophagocytic lymphohistiocytosis (HLH) remains to be determined. The aim was to develop and verify a population pharmacokinetic (PPK) model, and then provide references for the optimization of dose regimen of RUX in children with HLH.

METHODS

A total of 189 RUX concentrations from 32 children were included. The PPK model was established using the nonlinear mixed-effects model approach. Predictive performance and stability of the final PPK model were evaluated. The exposure of RUX in different clinical scenarios was simulated through Monte Carlo simulations.

RESULTS

A one-compartment model with first-order absorption and linear elimination was identified to describe the disposition of RUX. The absorption rate constant (K_a) in the final PPK model was 1.05 h^-1, and the apparent clearance (CL/F) and volume of distribution (V/F) were 9.80 L/h and 30.6 L, respectively. Coadministration with triazoles (TZS) and azithromycin (AZM) resulted in approximately 31.0% and 32.4% reductions in the CL/F of RUX, respectively. Multiple evaluation procedures showed satisfactory predictive performance and stability of the final model. Monte Carlo simulations showed that the exposure of RUX was significantly affected by the coadministration with TZS and/or AZM under different clinical scenarios.

CONCLUSION

For the first time, a PPK model of RUX in children with HLH was developed and evaluated. The coadministration with TZS and/or AZM were found to reduce the clearance of RUX in children. These findings could provide new insights for the precise treatment of RUX in children with HLH.

Haemophagocytic Lymphohistiocytosis Associated With Anaplastic Large-Cell Lymphoma in a Young Woman

Haemophagocytic lymphohistiocytosis is a syndrome of excessive immunological activation that can be triggered by various diseases, including haematological cancers. We report a case of a 25-year-old woman presenting with constitutional symptoms and a painful thoracic mass of four months duration. Laboratory exams showed pancytopenia, hypertriglyceridemia and extremely high serum ferritin levels. A whole-body computed tomography (CT) scan revealed splenomegaly and highlighted the mass on the deep tissues of the left breast; the biopsy was compatible with anaplastic large-cell lymphoma. Additionally, a bone marrow biopsy revealed haemophagocytosis, fulfilling the criteria for associated haemophagocytic lymphohistiocytosis. The patient was quickly sent for chemotherapy followed by autologous haematopoietic cell transplantation. She achieved a complete metabolic response and has been in clinical remission after nearly four years of follow-up. We emphasise the benefit of a timely diagnosis and intervention which were the keys to success in this case.

Case report: Durable response to ruxolitinib in a child with TREX1-related disorder

Background

JAK inhibitors are useful in treating interferonopathies, presumably because they downregulate the JAK/STAT signaling. There are limited studies about the safety and effectiveness of using JAK inhibitors in children with TREX1-related disorders.

Case presentation

We report an 8-year-old female who presented at five years of age with features suggestive of hemophagocytic lymphohistiocytosis (HLH)-like disorder. The infectious disease workup was negative. Neurological assessment was normal. A brain CT scan was performed because of headache. It showed a faint subcortical calcification at right frontal lobe and almost symmetrical calcification within the basal ganglia. Brain MRI showed bilateral symmetrical globus pallidus, high T1 signal intensities, and a few scattered nonspecific FLAIR hyperintensities in subcortical and deep white matter. IVIG as an immune modulating agent was administered initially which led to the resolution of fever, improvement of blood count parameters, inflammatory markers, and normalization of liver enzymes. The child remained afebrile with no significant events for several months, then had disease flare up. The patient was started on pulse methylprednisolone 30 mg/kg for three days, then continued on 2 mg/kg. Whole exome sequencing revealed a novel heterozygous missense TREX1 mutation NM_016381.3:c.223G > A p.(Glu75Lys). The child was started on ruxolitinib, 5 mg orally twice daily. The child has prolonged, durable remission after initiating ruxolitinib with no adverse effects. Steroids were tapered off and the patient is no longer on IVIG. The patient is still on ruxolitinib for more than two years.

Conclusion

This case highlights the potential role of ruxolitinib in the treatment of TREX1-related disorders. A longer follow-up period is required to evaluate the long-term outcome.