Emapalumab for adult and pediatric patients with hemophagocytic lymphohistiocytosis

Management of hematological patients requiring emergency chemotherapy in the intensive care unit

Hematological malignancies may require rapid-onset treatment because of their short doubling time, notably observed in acute leukemias and specific high-grade lymphomas. Furthermore, in targeted onco-hematological scenarios, chemotherapy is deemed necessary as an emergency measure when facing short-term, life-threatening complications associated with highly chemosensitive hematological malignancies. The risks inherent in the disease itself, or in the initiation of treatment, may then require admission to the intensive care unit (ICU) to optimize monitoring and initial management protocols. Hyperleukocytosis and leukostasis in acute leukemias, tumor lysis syndrome, and disseminated intravascular coagulation are the most frequent onco-hematological complications requiring the implementation of emergency chemotherapy in the ICU. Chemotherapy must also be started urgently in secondary hemophagocytic lymphohistiocytosis. Tumor-induced microangiopathic hemolytic anemia and plasma hyperviscosity due to malignant monoclonal gammopathy represent infrequent yet substantial indications for emergency chemotherapy. In all cases, the administration of emergency chemotherapy in the ICU requires close collaboration between intensivists and hematology specialists. In this review, we provide valuable insights that aid in the identification and treatment of patients requiring emergency chemotherapy in the ICU, offering diagnostic tools and guidance for their overall initial management.

Case Report: Refractory macrophage activation syndrome requiring high-dose anakinra, emapalumab, and etoposide therapy in early-onset systemic juvenile idiopathic arthritis associated with adenoviremia

Macrophage activation syndrome (MAS) is a life-threatening condition characterized by the excessive stimulation of macrophages and T lymphocytes, provoked by infections, malignancy, and autoimmune or autoinflammatory conditions such as systemic juvenile idiopathic arthritis (sJIA). Clinical signs of sJIA may include high-spiking, quotidian fevers, lymphadenopathy, hepatosplenomegaly, and a salmon-colored migratory, evanescent rash. By contrast, MAS is characterized by unremitting fevers and diffuse, fixed, maculopapular rashes. In addition to hepatosplenomegaly and lymphadenopathy, patients with MAS may also have clinical signs of coagulopathy, as well as cardiac, lung, renal, and central nervous system dysfunction. The empiric treatment for MAS is initially high-dose IV corticosteroids, but usually requires addition of immunomodulators such as tacrolimus or a biologic such as Anakinra to control. The addition of immunotherapies for MAS has improved patient outcomes. We present a 2-year-old male patient with a history of early-onset sJIA, who presented with MAS refractory to corticosteroids and anakinra triggered by adenoviremia that required addition of emapalumab to control. We believe this is the first reported case of a combination of immunosuppressive therapy of emapalumab, etoposide, anakinra, tacrolimus, and corticosteroids used in the successful treatment of infection-induced MAS in early-onset sJIA. Given the lack of treatment guidelines and approved therapies for MAS, alternative strategies should be considered for patients with an intractable course.

Targeted Treatment of Diseases of Immune Dysregulation

Increasing molecular knowledge of autoinflammatory and autoimmune disorders has enabled more targeted treatment of these conditions. Treatment of inflammasomopathies is often aimed at interleukin-1 (IL-1) blockade, with potential use of other inhibitors targeting cytokines such as IL-18 and IL-6. Interferonopathies and some disorders with overlap features of autoimmunity and autoinflammation may improve with Janus kinase inhibition. Autoimmune conditions may also respond to inhibition of different cytokines, as well as to inhibition of T and B lymphocytes. Effective treatment is increasingly possible through targeted/precision medicine approaches.

When to suspect inborn errors of immunity in Epstein-Barr virus-related lymphoproliferative disorders

BACKGROUND

More than 95% of humans have been infected with Epstein-Barr virus (EBV) and develop anti-EBV IgG antibodies, conferring immunity. However, among specific populations, EBV may induce a range of B-cell lymphoproliferative disorders (LPDs). EBV may also contribute to T-cell and natural killer (NK)-cell lymphoproliferation. The immune system is essential to prevent infection and development of cancer. Inborn errors of immunity (IEIs) are a heterogenous group of more than 450 genetic disorders predisposing to severe and/or recurrent infection, autoimmunity, autoinflammation, or early-onset/severe neoplasia or lymphoproliferation. Monogenic disorders of T-cell and B-cell signalling are classic IEIs that predispose to EBV-associated LPDs.

OBJECTIVES

We aimed to outline the various clinical manifestations of EBV-associated LPDs and the underlying IEIs associated with such presentations and discuss the recommended management and therapeutic options pertaining to these disorders.

SOURCES

We searched PubMed, Embase, and Web of Science Core Collection on 30 September 2021. Clinical studies, systematic reviews, narrative reviews, and case reports were identified through search strategy and cross reference from primary literature.

CONTENT

Effective T-cell and NK-cell cytotoxicity towards EBV-infected B cells relies on intact MAGT1-dependent NKG2D pathways and signalling lymphocyte activation molecular-associated protein-dependent signalling lymphocyte activation molecular receptors. The interaction between CD27 and CD70 is also critical to drive the expansion of EBV-specific T cells. IEIs due to T-cell and B-cell signalling defects and/or impaired T-cell and NK-cell cytotoxicity predispose to EBV-related lymphoproliferation. This includes classic disorders such as X-linked lymphoproliferative disease 1 (due to SH2D1A mutations), X-linked lymphoproliferative disease 2 (XIAP), and other genetic diseases, such as ITK, MAGT1, CD27, CD70, CTPS1, RASGRP1, and CORO1A deficiencies. EBV-driven lymphoproliferation may manifest to a lesser degree in MST1/STK4, DOCK8, STIM1, CORO1A, IL21R, PIK3CD gain-of-function, and PI3KR1 deficiencies.

IMPLICATIONS

Early screening for IEIs is indicated in cases of EBV-related lymphoproliferation because different forms of IEIs have specific prognostic and therapeutic implications.

Successful use of emapalumab in refractory hemophagocytic lymphohistiocytosis in a child with Chédiak-Higashi syndrome: a case report

BACKGROUND

Hemophagocytic lymphohistiocytosis is a life-threatening disease heralded by fever, cytopenia, hepatosplenomegaly, and multisystem organ failure. Its association with genetic mutations, infections, autoimmune disorders, and malignancies is widely reported.

CASE PRESENTATION

A 3-year-old male Arab Saudi patient with insignificant past medical history and parental consanguinity presented with abdominal distension of moderate severity and persistent fever despite receiving antibiotics. This was accompanied by hepatosplenomegaly and silvery hair. The clinical and biochemical profiles were suggestive of Chédiak-Higashi syndrome with hemophagocytic lymphohistiocytosis. The patient received the hemophagocytic lymphohistiocytosis-2004 chemotherapy protocol and had multiple hospital admissions mainly due to infections and febrile neutropenia. After achieving the initial remission, the patient's disease reactivated and did not respond to reinduction with the hemophagocytic lymphohistiocytosis-2004 protocol. Due to the disease reactivation and intolerance of conventional therapy, the patient commenced emapalumab. The patient was successfully salvaged and underwent an uneventful hematopoietic stem cell transplantation.

CONCLUSIONS

Novel agents such as emapalumab can be helpful for the management of refractory, recurrent, or progressive disease, while avoiding the toxicities of conventional therapy. Due to a paucity of available data on emapalumab, additional data are needed to establish its role in hemophagocytic lymphohistiocytosis treatment.

Hemophagocytic Lymphohistiocytosis and Clostridium difficile Infection: A Diagnostic Dilemma

Hemophagocytic lymphohistiocytosis (HLH) is a life-threatening condition that often goes underdiagnosed because of broad and non-specific symptomatology, usually consisting of fever, hepatosplenomegaly, and multiorgan failure. This disorder can be driven by genetic components (primary) or acquired (secondary) causes related to infectious, autoimmune, or malignant processes. HLH pathogenesis derives from overactive and dysregulated immune system responses. This disorder often goes misdiagnosed because of similar clinical and laboratory findings to septicemia. Cases of HLH most commonly coexist with Epstein-Barr virus (EBV). Clostridium difficile (C. difficile) infection causing HLH has also rarely been described in the literature. A firm knowledge of HLH association with clostridial infection is essential to recognize. A presumed diagnosis of HLH in a decompensating patient may prompt the initiation of appropriate treatment earlier and improve clinical outcomes. We discuss the diagnostic and management difficulties associated with these concurrent conditions.

Biomarkers in Systemic Juvenile Idiopathic Arthritis, Macrophage Activation Syndrome and Their Importance in COVID Era

Systemic juvenile idiopathic arthritis (sJIA) and its complication, macrophage activation syndrome (sJIA-MAS), are rare but sometimes very serious or even critical diseases of childhood that can occasionally be characterized by nonspecific clinical signs and symptoms at onset-such as non-remitting high fever, headache, rash, or arthralgia-and are biologically accompanied by an increase in acute-phase reactants. For a correct positive diagnosis, it is necessary to rule out bacterial or viral infections, neoplasia, and other immune-mediated inflammatory diseases. Delays in diagnosis will result in late initiation of targeted therapy. A set of biomarkers is useful to distinguish sJIA or sJIA-MAS from similar clinical entities, especially when arthritis is absent. Biomarkers should be accessible to many patients, with convenient production and acquisition prices for pediatric medical laboratories, as well as being easy to determine, having high sensitivity and specificity, and correlating with pathophysiological disease pathways. The aim of this review was to identify the newest and most powerful biomarkers and their synergistic interaction for easy and accurate recognition of sJIA and sJIA-MAS, so as to immediately guide clinicians in correct diagnosis and in predicting disease outcomes, the response to treatment, and the risk of relapses. Biomarkers constitute an exciting field of research, especially due to the heterogeneous nature of cytokine storm syndromes (CSSs) in the COVID era. They must be selected with utmost care-a fact supported by the increasingly improved genetic and pathophysiological comprehension of sJIA, but also of CSS-so that new classification systems may soon be developed to define homogeneous groups of patients, although each with a distinct disease.

COVID‐19‐associated secondary hemophagocytic lymphohistiocytosis requiring hematopoietic cell transplant

Coronavirus disease 2019 (COVID‐19) infection causes a variety of extrapulmonary complications in pediatric patients. Multisystem inflammatory syndrome and hemophagocytic lymphohistiocytosis (HLH) are related to hypercytokinemia in COVID‐19 patients. HLH is a disorder of exaggerated inflammation resulting in a cytokine storm and unrestricted hemophagocytosis. HLH can be primary (familial) or secondary (acquired). Secondary HLH (sHLH) can occur in patients with rheumatologic, oncologic, or infectious diseases. The link between COVID‐19 and HLH has been reported in pediatric patients. Here we report a case of a pediatric patient who developed refractory sHLH secondary to COVID‐19 infection and required a hematopoietic cell transplant for the cure.