Haemophagocytic lymphohistiocytosis post-ChAdOx1 nCoV-19 vaccine: A rare case.

The severe acute respiratory syndrome coronavirus 2 pandemic started in December 2019, spread like wildfire and took an immense toll on human life. ChAdOx1 nCoV-19 vaccine was used worldwide for the prevention of Covid-19. Covid-19 has been implicated in the causation of severe haemophagocytic lymphohistiocytosis (HLH) syndrome. However, the same has not been reported with ChAdOx1 nCoV-19 vaccine in the literature. We report a young man who developed secondary HLH post-ChAdOx1 nCoV-19 vaccination.

Visceral leishmaniasis complicated with hemophagocytic lymphohistiocytosis and resistant to amphotericin B: a case report.

INTRODUCTION: Hemophagocytic lymphohistiocytosis characterized by hemophagocytosis leading to uncontrolled inflammation; the most common etiology in secondary cases of hemophagocytic lymphohistiocytosis is viral infections, especially Epstein-Barr virus. Visceral leishmaniasis is a vectorborne protozoal disease caused by Leishmania donovani complex. It is common in tropical and subtropical regions, with 50,000-90,000 new cases annually. CASE PRESENTATION: A 15-month-old Arab female was admitted to our hospital with 15 days of fever and decreased weight. On clinical examination, she had a markedly enlarged liver and spleen that were palpable 4 cm and 6 cm below the costal margin, respectively. The peripheral blood smear showed hypochromic microcytic anemia, poikilocytosis, reactive lymphocytosis, and mild thrombocytopenia. Bone marrow aspiration did not show malignancy or any other pathological findings. The patient was put on antibiotic therapy without improvement. Repeated bone marrow aspiration showed erythrophagocytosis; intracellular small round organisms looked like the amastigote form of Leishmania (Donovan bodies) with no evidence of malignancies. Her lab values showed ferritin greater than 500 ug/L, pancytopenia, and hypertriglyceridemia. The patient was diagnosed with hemophagocytic lymphohistiocytosis secondary to visceral leishmaniasis. CONCLUSION: Hemophagocytic lymphohistiocytosis secondary to visceral leishmaniasis is an extensively rare phenomenon in the medical literature that causes challenges in diagnosis and management. Steroids should be used wisely to not cover the symptoms of infections or malignancy, and amphotericin B resistance should be kept in mind in unresponsive Leishmania cases.

Hyperferritinemia Screening to Aid Identification and Differentiation of Patients with Hyperinflammatory Disorders.

High ferritin is an important and sensitive biomarker for the various forms of hemophagocytic lymphohistiocytosis (HLH), a diverse and deadly group of cytokine storm syndromes. Early action to prevent immunopathology in HLH often includes empiric immunomodulation, which can complicate etiologic work-up and prevent collection of early/pre-treatment research samples. To address this, we instituted an alert system at UPMC Children's Hospital where serum ferritin > 1000 ng/mL triggered real-time chart review, assessment of whether the value reflected "inflammatory hyperferritnemia (IHF)", and biobanking of remnant samples from consenting IHF patients. We extracted relevant clinical data; periodically measured serum total IL-18, IL-18 binding protein (IL-18BP), and CXCL9; retrospectively classified patients by etiology into infectious, rheumatic, or immune dysregulation; and subjected a subgroup of samples to a 96-analyte biomarker screen. 180 patients were identified, 30.5% of which had IHF. Maximum ferritin levels were significantly higher in patients with IHF than with either hemoglobinopathy or transplant, and highly elevated total IL-18 levels were distinctive to patients with Stills Disease and/or Macrophage Activation Syndrome (MAS). Multi-analyte analysis showed elevation in proteins associated with cytotoxic lymphocytes in all IHF samples when compared to healthy controls and depression of proteins such as ANGPT1 and VEGFR2 in samples from hyperferritinemic sepsis patients relative to non-sepsis controls. This real-time IFH screen proved feasible and efficient, validated prior observations about the specificity of IL-18, enabled early sample collection from a complex population, suggested a unique vascular biomarker signature in hyperferritinemic sepsis, and expanded our understanding of IHF heterogeneity.

Acute hepatitis A with haemophagocytic lymphohistiocytosis: G-6PD deficiency-induced haemolytic anaemia and bile cast nephropathy.

Hepatitis A virus (HAV) infection typically presents as a self-limiting illness but it can cause debilitating symptoms and rarely fulminant hepatitis (acute liver failure), which is often fatal. WHO estimates that in 2016, 7134 persons died from hepatitis A worldwide (accounting for 0.5% of the mortality due to viral hepatitis). Fulminant hepatic failure is observed in less than 1% of cases of acute viral hepatitis A. Haemophagocytic lymphohistiocytosis (HLH) is a clinical syndrome of excessive inflammation and tissue destruction owing to abnormal immune activation. Acquired HLH due to viral infections (also known as virus-associated haemophagocytic syndrome) is most commonly associated with Epstein-Barr virus and cytomegalovirus (CMV). HAV-associated HLH has been rarely reported. Haemolysis of mild to moderate degree is not unheard of in cases of hepatitis A, which is often immune-mediated. Here, we present the case of a man in his 30s, with G6PD deficiency unmasked by acute viral hepatitis A, which later on progressed to hyperacute liver failure, HLH and renal failure.

Clinicopathological characteristics, prognostic factors, and outcomes of elderly patients with lymphoma-associated hemophagocytic lymphohistiocytosis: A multicenter analysis.

BACKGROUND: Lymphoma is the most common secondary cause of hemophagocytic lymphohistiocytosis (HLH) in adults. Lymphoma-associated HLH (LA-HLH) in the elderly population is not rare, however, little has been reported regarding clinicopathological characteristics, prognostic factors, and outcomes of LA-HLH in the elderly population. METHODS: We retrospectively analyzed a multicenter cohort of elderly patients with LA-HLH. Clinicopathological features and treatment information were collected. The impacts of baseline characteristics and treatments on survival outcomes were analyzed. RESULTS: A total of 173 elderly patients with LA-HLH were included. Compared with young patients, elderly patients showed different clinical and laboratory features. Regarding lymphoma subtypes, B-cell lymphoma was more common in elderly patients (elderly 61.3% vs. young 32.3%, p < 0.001) while T/NK-cell lymphoma was more common in young patients (65.3% vs. 35.3%, p < 0.001). The median survival of elderly patients with LA-HLH was only 92 days. The prior use of HLH therapy or etoposide-containing HLH therapy was not associated with improved overall survival. T/NK-cell subtype, a lower platelet count (≤53 × 109/L), a lower albumin level (≤32.1 g/L), a higher LDH level (>1407 U/L), and a higher creatinine level (>96.8 µmol/L) were independent predictors of decreased overall survival and 60-day survival. A prognostic index was established and demonstrated to be robust in predicting the overall survival and 60-day survival of elderly patients with LA-HLH. CONCLUSIONS: LA-HLH in elderly patients displayed heterogeneous clinicopathological features and survival outcomes. Treatments need to be optimized to improve the outcomes of elderly patients with LA-HLH.

Haemophagocytic lymphohistiocytosis secondary to disseminated histoplasmosis in a patient with leprosy.

Multidrug therapy has significantly reduced the global burden of Hansen's disease; however, complications from long-term treatment persist. A male resident of southern Kentucky, in his 30s and of Micronesian descent, presented with worsening abdominal pain associated with anorexia, fatigue, functional decline and occasional haemoptysis. He was compliant with multidrug therapy for leprosy. Laboratory investigations revealed pancytopenia. He was initially treated under a sepsis protocol and later switched to high-dose steroids due to a suspected immune reaction from missed corticosteroid doses. Despite aggressive treatment for refractory pancytopenia, the patient's condition deteriorated, and he passed away from cardiac arrest. Posthumous bone marrow biopsy revealed haemophagocytic lymphohistiocytosis secondary to disseminated histoplasmosis with bone marrow infiltration. This case highlights the importance of proactive fungal screening in immunocompromised leprosy patients, particularly in endemic regions, as early detection and timely intervention can prevent severe complications.

[Splenectomy as definitive surgical treatment for hemophagocytic lymphohistiocytosis]. / Esplenectomía como tratamiento quirúrgico definitivo para linfohistiocitosis hemofagocítica.

Background: Hemophagocytic syndrome or hemophagocytic lymphohistiocytosis (HL) is an immune hyperactivation of multifactorial etiology, characterized by excessive activation of lymphocytes and macrophages, as well as numerous pro-inflammatory cytokines. It has a non-specific and highly variable clinical presentation, with splenomegaly being one of the clinical manifestations. Due to its nature, it can manifest during childhood or adult life, which is why it is a disease of diagnostic and therapeutic complexity. Clinical case: 38-year-old male patient without comorbidities, who presented with abdominal pain, choluria, fever > 38 °C and diaphoresis of more than 10 days of evolution. A bone marrow aspirate was performed as part of the diagnostic approach with data compatible with hemophagocytosis and cytopenias. The immunosuppressive management did not show the expected response, which is why an open splenectomy was performed as the last therapeutic option with adequate hematological control. A documentary review of the disease was carried out, and of the therapeutic options, emphasizing surgical management in case of refractoriness to medical treatment. Conclusions: Splenectomy increases the overall survival rate and the time free of HL progression, even though there are still no studies to determine with certainty the ideal time to perform a splenectomy in patients with pancytopenia without splenomegaly who suffer from hemophagocytic syndrome.

Introducción: el síndrome hemofagocítico o linfohistiocitosis hemofagocítica (LH) es una hiperactivación inmune de etiología multifactorial, caracterizada por activación excesiva de linfocitos y macrófagos, así como por numerosas citocinas proinflamatorias. Tiene una presentación clínica poco específica y muy variable, y la esplenomegalia es una de las manifestaciones clínicas. Debido a su naturaleza puede manifestarse durante la infancia o la vida adulta, por lo que es una enfermedad de complejidad diagnóstica y terapéutica. Caso clínico: paciente del sexo masculino de 38 años sin comorbilidades, quien presentó dolor abdominal, coluria, fiebre > 38 °C y diaforesis de más de 10 días de evolución. Se le hizo aspirado de médula ósea como parte del abordaje diagnóstico con datos compatibles con hemofagocitosis y citopenias. El manejo inmunosupresor no mostró la respuesta esperada, por lo que se hizo esplenectomía abierta como última opción terapéutica con adecuado control hematológico. Se hizo una revisión documental de la enfermedad y de las opciones terapéuticas con énfasis en el manejo quirúrgico en caso de refractariedad al tratamiento médico. Conclusiones: la esplenectomía aumenta la tasa de supervivencia general y el tiempo libre de progresión de la LH, aunque no hay todavía estudios para determinar con certeza el tiempo ideal para hacer una esplenectomía en pacientes con pancitopenia sin esplenomegalia que padezcan síndrome hemofagocítico.

Tuberculosis of the bone marrow with secondary hemophagocytic lympho-histiocytosis presenting as obstructive jaundice: A clinician's challenge for the ages.

Tuberculosis. a disease of great public concern, is spread through inhalation of micro-droplets from an infected person. Despite lungs being the primary site, there may be multisystemic involvement, very rarely involving bone marrow, a dreaded manifestation of disseminated tuberculosis, associated with high mortality and morbidity. We report a case of tuberculosis of bone marrow with concomitant secondary hemophagocytic lympho-histiocytosis, bringing into light the importance of clinical suspicion and evaluation of bone marrow being a primary site of involvement in patients of disseminated tuberculosis.

History of Hemophagocytic Lymphohistiocytosis.

Hemophagocytic lymphohistiocytosis (HLH) is a severe cytokine storm syndrome (CSS), which until the turn of the century, was barely known but is now receiving increased attention. The history of HLH dates back to 1939 when it was first described in adults, to be followed in 1952 by the first description of its primary, familial form in children. Secondary forms of HLH are far more frequent and occur with infections, malignancies, metabolic diseases, iatrogenic immune suppression, and autoinflammatory/autoimmune diseases. Identification of the genetic defects leading to the defective function of natural killer (NK) cells and cytotoxic T cells as well as the corresponding mouse models have revolutionized our understanding of HLH and of immune function. Diagnosis relies on clinical and laboratory criteria; functional and genetic tests can help separate primary from secondary forms. Treatment with immunochemotherapy and hematopoietic stem cell transplantation has considerably improved survival in children with primary HLH, a formerly uniformly fatal disease.

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.

Genetics of Acquired Cytokine Storm Syndromes : Secondary HLH Genetics.

Secondary hemophagocytic lymphohistiocytosis (sHLH) has historically been defined as a cytokine storm syndrome (CSS) occurring in the setting of triggers leading to strong and dysregulated immunological activation, without known genetic predilection. However, recent studies have suggested that existing underlying genetic factors may synergize with particular diseases and/or environmental triggers (including infection, autoimmune/autoinflammatory disorder, certain biologic therapies, or malignant transformation), leading to sHLH. With the recent advances in genetic testing technology, more patients are examined for genetic variations in primary HLH (pHLH)-associated genes, including through whole exome and whole genome sequencing. This expanding genetic and genomic evidence has revealed HLH as a more complex phenomenon, resulting from specific immune challenges in patients with a susceptible genetic background. Rather than a simple, binary definition of pHLH and sHLH, HLH represents a spectrum of diseases, from a severe complication of common infections (EBV, influenza) to early onset familial diseases that can only be cured by transplantation.

The History of Macrophage Activation Syndrome in Autoimmune Diseases.

In 1979, it became recognized in the literature that what we call hemophagocytic lymphohistiocytosis (HLH) was a nonmalignant disease of histiocytes. Subsequently a familial form and a secondary form of HLH were differentiated. When HLH is secondary to an autoimmune disease, rheumatologists refer to this entity as macrophage activation syndrome (MAS) to differentiate it from HLH itself. Although the first cases of MAS likely appeared in the literature in the 1970s, it was not until 1985 that the term activated macrophages was used to describe patients with systemic juvenile idiopathic arthritis (sJIA) complicated by MAS and the term macrophage activation syndrome first appeared in the title of a paper in 1993.MAS is one of the many types of secondary HLH and should not be confused with primary HLH. Experience has taught that MAS secondary to different autoimmune diseases is not equal. In the 30 years since initial description in patients with sJIA, the clinical spectrum, diseases associated with MAS, therapy, and understanding the pathogenesis have all made significant gains. The diagnostic/classification criteria for MAS secondary to sJIA, SLE, RA, and KD differ based on the different laboratory abnormalities associated with each (Ahn et al., J Rheumatol 44:996-1003, 2017; Han et al., Ann Rheum Dis 75:e44, 2016; Ravelli et al., Ann Rheum Dis 75:481-489, 2016; Borgia et al., Arthritis Rheumatol 70:616-624, 2018). These examples include the thrombocytosis associated with sJIA, a chronic generalized activation of the immune system, leading to elevations of fibrinogen and sIL-2R, low platelet count associated with SLE, and more acute inflammation associated with KD. Therefore, individual diagnostic criteria are required, and they all differ from the diagnostic criteria for HLH, which are based on a previously non-activated immune system (Ahn et al., J Rheumatol 44:996-1003, 2017; Han et al., Ann Rheum Dis 75:e44, 2016; Ravelli et al., Ann Rheum Dis 75:481-489, 2016; Borgia et al., Arthritis Rheumatol 70:616-624, 2018; Henter et al., Pediatr Blood Cancer 48:124-131, 2007). This helps to explain why the HLH diagnostic criteria do not perform well in MAS.The initial treatment remains high-dose steroids and IVIG followed by the use of a calcineurin inhibitor for resistant cases. IVIG can be used if there is a concern about malignancy to wait for appropriate investigations or with steroids. Interluekin-1 inhibition is now the next therapy if there is a failure to respond to steroids and calcineurin inhibitors. Advances in understanding the mechanisms leading to MAS, which has been greatly aided by the use of mouse models of MAS and advances in genome sequencing, offer a bright future for more specific therapies. More recent therapies are directed to specific cytokines involved in the pathogenesis of MAS and can lead to decreases in the morbidity and mortality associated with MAS. These include therapies directed to inhibiting the JAK/STAT pathway and/or specific cytokines, interleukin-18 and gamma interferon, which are currently being studied in MAS. These more specific therapies may obviate the need for nonspecific immunosuppressive therapies including high-dose prolonged steroids, calcineurin inhibitors, and etoposide.

Genetics of Macrophage Activation Syndrome in Systemic Juvenile Idiopathic Arthritis.

Macrophage activation syndrome (MAS) is a life-threatening episode of hyperinflammation driven by excessive activation and expansion of T cells (mainly CD8) and hemophagocytic macrophages producing proinflammatory cytokines. MAS has been reported in association with almost every rheumatic disease, but it is by far most common in systemic juvenile idiopathic arthritis (SJIA). Clinically, MAS is similar to familial or primary hemophagocytic lymphohistiocytosis (pHLH), a group of rare autosomal recessive disorders linked to various genetic defects all affecting the perforin-mediated cytolytic pathway employed by NK cells and cytotoxic CD8 T lymphocytes. Decreased cytolytic activity in pHLH patients leads to prolonged survival of target cells associated with increased production of proinflammatory cytokines that overstimulate macrophages. The resulting cytokine storm is believed to be responsible for the frequently fatal multiorgan system failure seen in MAS. Whole exome sequencing as well as targeted sequencing of pHLH-associated genes in patients with SJIA-associated MAS demonstrated increased "burden" of rare protein-altering variants affecting the cytolytic pathway compared to healthy controls, suggesting that as in pHLH, genetic variability in the cytolytic pathway contributes to MAS predisposition. Functional studies of some of the novel variants have shown that even in a heterozygous state, their presence partially reduces cytolytic activity that may lead to increased cytokine production.

Cytokine Storm Syndromes Associated with Epstein-Barr Virus.

Epstein-Barr virus (EBV) is a ubiquitous and predominantly B cell tropic virus. One of the most common viruses to infect humans, EBV, is best known as the causative agent of infectious mononucleosis (IM). Although most people experience asymptomatic infection, EBV is a potent immune stimulus and as such it elicits robust proliferation and activation of the B-lymphocytes it infects as well as the immune cells that respond to infection. In certain individuals, such as those with inherited or acquired defects affecting the immune system, failure to properly control EBV leads to the accumulation of EBV-infected B cells and EBV-reactive immune cells, which together contribute to the development of often life-threatening cytokine storm syndromes (CSS). Here, we review the normal immune response to EBV and discuss several CSS associated with EBV, such as chronic active EBV infection, hemophagocytic lymphohistiocytosis, and post-transplant lymphoproliferative disorder. Given the critical role for cytokines in driving inflammation and contributing to disease pathogenesis, we also discuss how targeting specific cytokines provides a rational and potentially less toxic treatment for EBV-driven CSS.

Cytokine Storm Syndrome Associated with Hemorrhagic Fever and Other Viruses.

A wide variety of infections can trigger cytokine storm syndromes including those caused by bacteria, viruses, fungi and parasites. The most frequent viral trigger is Epstein-.Barr virus which is covered in Chapter 16. CSS associated with COVID-19 is also discussed separately (Chapter 22). This chapter will focus on other viruses including the hemorrhagic fever viruses, influenza, parainfluenza, adenovirus, parvovirus, hepatitis viruses, measles, mumps, rubella, enterovirus, parechovirus, rotavirus, human metapneumovirus and human T-lymphotropic virus. The published literature consists of many single case reports and moderate-sized case series reporting CSS, in most circumstances meeting the 2004 diagnostic criteria for hemophagocytic lymphohistiocytosis (HLH). There is no published clinical trial evidence specifically for management of HLH associated with these viruses. In some situations, patients received supportive therapy and blood product transfusions only but in most cases, they were treated with one or more of intravenous corticosteroids, intravenous immunoglobulin and/or etoposide. These were successful in many patients although in significant numbers progression of infection to CSS was associated with mortality.

Zoonotic Bacterial Infections Triggering Cytokine Storm Syndrome.

Zoonotic infections can result in life-threatening complications that can manifest with hemophagocytic lymphohistiocytosis (HLH)/cytokine storm syndrome (CSS). Bacteria constitute the largest group of zoonotic infection-related HLH cases. The growing list of zoonotic bacterial infections associated with HLH/CSS include Brucella spp., Rickettsia spp., Ehrlichia, Coxiella burnetii, Mycobacterium spp., and Bartonella spp. Patients most commonly present with fever, cytopenias, hepatosplenomegaly, myalgias, and less frequently with rash, jaundice, and lymphadenopathy.

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.

Murine Models of Familial Cytokine Storm Syndromes.

Hemophagocytic lymphohistiocytosis (HLH) is a hyperinflammatory disease caused by mutations in effectors and regulators of cytotoxicity in cytotoxic T cells (CTL) and natural killer (NK) cells. The complexity of the immune system means that in vivo models are needed to efficiently study diseases like HLH. Mice with defects in the genes known to cause primary HLH (pHLH) are available. However, these mice only develop the characteristic features of HLH after the induction of an immune response (typically through infection with lymphocytic choriomeningitis virus). Nevertheless, murine models have been invaluable for understanding the mechanisms that lead to HLH. For example, the cytotoxic machinery (e.g., the transport of cytotoxic vesicles and the release of granzymes and perforin after membrane fusion) was first characterized in the mouse. Experiments in murine models of pHLH have emphasized the importance of cytotoxic cells, antigen-presenting cells (APC), and cytokines in hyperinflammatory positive feedback loops (e.g., cytokine storms). This knowledge has facilitated the development of treatments for human HLH, some of which are now being tested in the clinic.

Murine Models of Secondary Cytokine Storm Syndromes.

Hemophagocytic lymphohistiocytosis (HLH) comprises a broad spectrum of life-threatening cytokine storm syndromes, classified into primary (genetic) or secondary (acquired) HLH. The latter occurs in a variety of medical conditions, including infections, malignancies, autoimmune and autoinflammatory diseases, acquired immunodeficiency, and metabolic disorders. Despite recent advances in the field, the pathogenesis of secondary HLH remains incompletely understood. Considering the heterogeneity of triggering factors and underlying diseases in secondary HLH, a large diversity of animal models has been developed to explore pivotal disease mechanisms. To date, over 20 animal models have been described that each recapitulates certain aspects of secondary HLH. This review provides a comprehensive overview of the existing models, highlighting relevant findings, discussing the involvement of different cell types and cytokines in disease development and progression, and considering points of interest toward future therapeutic strategies.

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.