Hemophagocytic lymphohistiocytosis: review of etiologies and management

Haemophagocytic lymphohistiocytosis secondary to Epstein-Barr and cytomegalovirus coinfection

Haemophagocytic lymphohistiocytosis (HLH) is a rare and life-threatening disorder caused by uncontrolled activation of the immune system, leading to phagocytosis of blood cells and cytokine storm. HLH can manifest in childhood due to a genetic mutation, but in adults HLH arises secondary to viral infections, autoimmune diseases or neoplastic processes. The most common viral infections associated with HLH are Epstein-Barr virus (EBV) and cytomegalovirus (CMV). EBV and CMV coinfection associated with HLH, however, is exceedingly rare. We present a case of HLH secondary to EBV and CMV coinfection in a young adult who presented with recurrent intermittent high-grade fevers and epistaxis. This case illustrates the importance of considering HLH in patients with idiopathic fevers and to consider all the potential aetiologies for HLH to ensure proper treatment.

Cytomegalovirus-Induced Hemophagocytic Lymphohistiocytosis in an Immunocompromised Patient with Inflammatory Bowel Disease

Hemophagocytic lymphohistiocytosis (HLH) is a rare and often fatal syndrome of immune hyperactivation, cytokine dysregulation, and severe inflammation. This severe syndrome is commonly triggered by infection, malignancy, autoimmunity, or immunosuppression. We present herein the case of a 56-year-old-female diagnosed with HLH triggered by an acute cytomegalovirus (CMV) infection with viremia in the context of immunosuppression for inflammatory bowel disease. This case highlights the importance of utilizing multiple diagnostic tools, prompt initiation of anti-hemophagocytic treatment, and management of the underlying etiology, to prevent significant morbidity and mortality.

Persistent Fever after COVID-19 Vaccination in a Patient with Ulcerative Colitis: A Call for Attention

The development of vaccinations has been game-changing in the ongoing effort to combat the COVID-19 pandemic. Until now, adverse effects are being reported at low frequency, including thrombocytopenia and myocarditis. Careful monitoring for any suspicious symptoms and signs following vaccination is necessary. We report a case of hemophagocytic lymphohistiocytosis (HLH) after mRNA COVID-19 vaccine in a 23-year-old female with ulcerative colitis. Diagnosis was made according to HLH-2004 criteria and the patient was treated with dexamethasone with response. Our report aimed to draw attention to the potential relation between COVID-19 vaccines and HLH and the necessity of continued surveillance, especially in at-risk populations such as those with underlying immune dysregulation.

Hemophagocytic lymphohistiocytosis in Egyptian children: diagnosis, treatment challenges, and outcome

BACKGROUND

Hemophagocyticlymphohistiocytosis (HLH) is a spectrum of immune activation which could be genetically determined, or secondary to an underlying illness. Our aim was to present the clinico-genetic aspects of HLH among Egyptian children and to evaluate the patterns of reactivation and outcome with illustrations of overlap manifestations.

RESEARCH DESIGNAND METHODS

We retrospectively collected the data of 55 patients with HLH, registered at Ain Shams University Children's Hospital,Cairo, Egypt.

RESULTS

Median age at diagnosis was 19 months (range 2-180), 33 patients (60%) fulfilled the diagnostic HLH criteria at presentation. Fourteen (25.45%) patients had secondary HLH, 15 (27.27%) patients had genetically documented familial HLH (11 had variants in UNC13D gene and one in PRF1 gene), 3 had Griscelli and Chediak-Higashi syndromes. Sixteen patients (29.1%) had reactivations, 8 (50%) of them had molecularly confirmed HLH. We report the death of 40 patients, the median duration from the diagnosis to death of 5 months mostly due to disease activity.

CONCLUSIONS

This study confirms that the nonspecific signs and symptoms of HLH are challenging. Genetic testing, though expensive and sophisticated, is integral for the diagnosis. The difficulty in finding non-related donors for stem cell transplantation and the early reactivations are the causes of the inferior outcome.

Cytokine Storm Syndrome Responsive to IL-1 Inhibition in Trisomy 21

Background

Cytokine storm syndromes (CSS) are life-threatening systemic inflammatory disorders caused by immune system dysregulation. They can lead to organ failure and are triggered by various factors, including infections, malignancy, inborn errors of immunity, and autoimmune conditions. Trisomy 21 (TS21), also known as Down syndrome, is a genetic disorder associated with immune dysfunction, increased infection susceptibility, and inflammation. While TS21 has been linked to infectious-triggered hyperinflammation, its role as a primary cause of CSS has not been confirmed. Case Presentation. We present a case of a 16-year-old male with TS21 with fever, rash, joint pain, and abdominal symptoms. Extensive investigations ruled out infections, autoimmune conditions, malignancies, and inborn errors of immunity as triggers for a CSS. The patient's symptoms improved with treatment using IL-1 inhibition and corticosteroids.

Conclusions

This case reinforces that TS21 is an immune dysregulation disorder and highlights the importance of considering CSS in TS21 patients, even when triggers are unclear. The positive response to IL-1 inhibition in this patient suggests that dysregulation of the IL-1 superfamily and the NLRP3 inflammasome may contribute to CSS in TS21. This finding raises the possibility of using IL-1 inhibition as a treatment approach for CSS in TS21 patients.

Infectious Diseases Evaluation of the Child With Suspected Hemophagocytic Lymphohistiocytosis

Hemophagocytic lymphohistiocytosis (HLH) is a syndrome of excessive and maladaptive inflammation. In this review, we discuss how the clinical and laboratory features of HLH overlap with infection and propose a diagnostic and treatment strategy to identify patients with infections mimicking HLH.

A Rare Case of Extranodal Natural Killer/T-cell Lymphoma, Nasal Type Associated With Hemophagocytic Lymphohistiocytosis in a Patient With Recurrent Sinusitis

We present a rare case of hemophagocytic lymphohistiocytosis (HLH) secondary to nasal-type extranodal natural killer/T-cell lymphoma (ENKL). Nasal-type ENKL is a rare subtype of non-Hodgkin's lymphoma usually associated with Epstein-Barr virus (EBV). The patient was a 19-year-old woman who presented with facial numbness, diminished hearing, and dysgeusia. She was febrile with palatal necrosis, loss of gag reflex, and cranial nerve palsies. Labs revealed neutropenia. Broad-spectrum antimicrobials, including amphotericin, were started. Given concern for invasive fungal disease, she underwent surgical debridement, which revealed inflamed fibrous tissue and extensive necrosis. Pathology showed no fungal elements or malignancy. Lack of clinical improvement and worsening palatal necrosis prompted additional debridement. Histology identified an atypical CD3+/CD56+ cellular infiltrate. Bone marrow biopsy showed prominent hemophagocytosis, but no malignancy. She met the criteria for HLH and high-dose dexamethasone was started. Her fevers resolved. Additional labs and nasal tissue sampling with EBV-encoded RNA staining were recommended. Flow cytometry was negative, but histology revealed ENKL nasal-type, with positive EBV-encoded RNA in situ hybridization. Plasma EBV DNA level was 11,518 IU/mL. The M-SMILE (dexamethasone, methotrexate, ifosfamide, l-asparaginase, and etoposide) regimen was initiated; one cycle led to marked improvement. EBV level returned to zero. Subsequent radiation and chemotherapy, followed by autologous stem cell transplant consolidation, led to complete remission. We conclude that ENKL may mimic invasive sinusitis clinically. Fibrinoid necrosis in vessels and surrounding tissues often leads to diagnostic delay. It is important to have a high degree of clinical suspicion for malignancy in cases of HLH and sinusitis unresponsive to appropriate therapy. Obtaining proper tissue, communication with the pathologist, and prompt initiation of therapy are crucial.

Hemophagocytic Lymphohistiocytosis (HLH) in Patients with Tick-Borne Illness: A Scoping Review of 98 Cases

Hemophagocytic lymphohistiocytosis (HLH) secondary to tick-borne infections is a rare but potentially life-threatening syndrome. We performed a scoping review according to PRISMA guidelines to systematically analyze the existing literature on the topic. A total of 98 patients were included, with a mean age of 43.7 years, of which 64% were men. Most cases, 31%, were reported from the USA. Immunosuppression was present in 21.4%, with the most common cause being previous solid organ transplantation. Constitutional symptoms were the most common, observed in 83.7% of the patients, while fever was reported in 70.4% of cases. Sepsis was present in 27.6%. The most common laboratory abnormalities in this cohort were thrombocytopenia in 81.6% of patients, while anemia, leukopenia, and leukocytosis were observed in 75.5%, 55.1%, and 10.2%, respectively. Liver enzyme elevation was noted in 63.3% of cases. The H-score was analyzed in 64 patients, with the mean value being 209, and bone marrow analysis was performed in 61.2% of patients. Ehrlichia spp. was the main isolated agent associated with HLH in 45.9%, followed by Rickettsia spp. in 14.3% and Anaplasma phagocytophilum in 12.2%. Notably, no patient with Powassan virus infection or Lyme borreliosis developed HLH. The most common complications were acute kidney injury (AKI) in 35.7% of patients, shock with multiple organ dysfunction in 22.5%, encephalopathy/seizure in 20.4%, respiratory failure in 16.3%, and cardiac complications in 7.1% of patients. Treatment included antibiotic therapy alone in 43.9%, while 5.1% of patients were treated with immunosuppressants alone. Treatment with both antibiotics and immunosuppressants was used in 51% of patients. Appropriate empiric antibiotics were used in 62.2%. In 43.9% of cases of HLH due to tick-borne disease, patients received only antimicrobial therapy, and 88.4% of those recovered completely without the need for immunosuppressive therapy. The mortality rate in our review was 16.3%, and patients who received inappropriate or delayed empiric therapy had a worse outcome. Hence, we suggest empiric antibiotic treatment in patients who are suspected of having HLH due to tick-borne disease or in whom diagnostic uncertainty persists due to diagnostic delay in order to minimize mortality.

Molecular Mutations in Histiocytosis: A Comprehensive Survey of Genetic Alterations

Histiocytosis represents a group of uncommon disorders characterized by the abnormal accumulation of specialized immune cells, such as macrophages, dendritic cells, or monocyte-derived cells, in various tissues and organs. Over 100 distinct subtypes have been documented, each displaying a broad spectrum of clinical presentations and histological characteristics. Till today, histiocytosis has been addressed through a combination of chemotherapy, radiotherapy, and surgery, with varying responses from individual patients. Due to its atypical symptoms, it has been prone to misdiagnosis. Advances in our understanding of the cellular and molecular aspects of these conditions are paving the way for improved diagnostic methods and targeted therapies. Researchers have extensively investigated various mutations in patient samples. However, no paper has yet provided a comprehensive summary of the collective analysis of mutations and pathways. Hence, this paper consolidates research efforts that specifically concentrate on gene mutations identified in patient samples of different subtypes of histiocytosis. These insights are essential for developing targeted therapies and improving diagnosis. Further, it provides potential insights to enhance the development of more effective therapeutic approaches for rare diseases.

Human PLCG2 haploinsufficiency results in a novel natural killer cell immunodeficiency

BACKGROUND

Although most individuals effectively control herpesvirus infections, some suffer from severe and/or recurrent infections. A subset of these patients possess defects in natural killer (NK) cells, lymphocytes that recognize and lyse herpesvirus-infected cells; however, the genetic etiology is rarely diagnosed. PLCG2 encodes a signaling protein in NK-cell and B-cell signaling. Dominant-negative or gain-of-function variants in PLCG2 cause cold urticaria, antibody deficiency, and autoinflammation. However, loss-of-function variants and haploinsufficiency have not been reported to date.

OBJECTIVES

The investigators aimed to identify the genetic cause of NK-cell immunodeficiency in 2 families and herein describe the functional consequences of 2 novel loss-of-function variants in PLCG2.

METHODS

The investigators employed whole-exome sequencing in conjunction with mass cytometry, microscopy, functional assays, and a mouse model of PLCG2 haploinsufficiency to investigate 2 families with NK-cell immunodeficiency.

RESULTS

The investigators identified novel heterozygous variants in PLCG2 in 2 families with severe and/or recurrent herpesvirus infections. In vitro studies demonstrated that these variants were loss of function due to haploinsufficiency with impaired NK-cell calcium flux and cytotoxicity. In contrast to previous PLCG2 variants, B-cell function remained intact. Plcg2+/- mice also displayed impaired NK-cell function with preserved B-cell function, phenocopying human disease.

CONCLUSIONS

PLCG2 haploinsufficiency represents a distinct syndrome from previous variants characterized by NK-cell immunodeficiency with herpesvirus susceptibility, expanding the spectrum of PLCG2-related disease.

Clinical approach to a child with hemophagocytic lymphohistiocytosis and bilateral optic nerve head infiltration: A case report and brief literature review

Key Clinical Message

Infiltrative optic neuropathy in hemophagocytic lymphohistiocytosis is rare but could potentially lead to visual loss. Cytomegalovirus (CMV) optic neuritis, drug toxicity, and CNS involvement with increased intracranial pressure (ICP) are differential diagnoses that have to be considered.

Abstract

In this report, we introduced a known case of hemophagocytic lymphohistiocytosis (HLH) with progressive visual loss due to bilateral optic nerve head (ONH) involvement. A 9-year-old boy with a history of HLH from 6 months ago was referred to the ophthalmic emergency department with a complaint of painless progressive blurred vision in his right eye. The fundus examination found an optic disc swelling and peripapillary hemorrhage in the right eye. The left fundus examination showed a mild ONH blurred margin. Systemic evaluations including brain and orbital MRI with gadolinium enhancement and CSF analysis showed optic nerve and brain involvement with tumoral cells. Despite systemic chemotherapy with etoposide, the disease had a progressive course so in the last follow-up visit, fundus examination revealed disc swelling, retinal edema, and epiretinal hemorrhage in both eyes and visual acuity deteriorated to no light perception and counting fingers in the right and left eye, respectively. ONH involvement in HLH is rare but could be sight-threatening. Differential diagnoses that should be investigated include neoplastic infiltrative optic neuropathy, cytomegalovirus (CMV) optic neuritis, drug toxicity, and CNS involvement with increased intracranial pressure (ICP).

Macrophage activation syndrome induced by Staphylococcus Epidermidis in a pediatric patient with cystic fibrosis and familial Mediterranean fever

Staphylococcus epidermidis (S. epidermidis) is the most frequently isolated member of the coagulase-negative staphylococci, which colonizes the skin and mucous membranes of the human body. Despite being a component of the normal flora, S. epidermidis can act as an opportunistic pathogen and is frequently implicated in both bacterial and nosocomial infections. Macrophage activation syndrome (MAS) is a rare but potentially fatal disease that occurs as a result of increased activation and proliferation of T lymphocytes and macrophages in response to infections and immune mediated diseases. It is very rare in patients with cystic fibrosis. Here we report a case of an 8-year-old girl with cystic fibrosis and familial Mediterranean fever who developed MAS after contracting a S. epidermidis infection.

Haemophagocytic syndrome caused by disseminated nontuberculous mycobacterial infection

A female patient in her 30s presented to the emergency department with a 10-day history of fever, weakness and diaphoresis. Subsequent investigations revealed a diagnosis of haemophagocytic syndrome, secondary to disseminated non-tuberculous mycobacterial infection affecting the bone marrow, lungs, lymph nodes and skin. The bone marrow culture confirmed the presence of Mycobacterium avium infection. The patient's haemophagocytic syndrome was managed using the HLH-2004 chemoimmunotherapy, and M. avium infection was treated with a combination of clarithromycin, ethambutol, rifampicin, ciprofloxacin and amikacin. Throughout her hospitalisation, the patient faced several serious complications arising from both the medications and the prolonged hospital stay (lasting 12 months). However, these complications were promptly identified and effectively managed through a multidisciplinary and comprehensive approach. This approach was crucial in achieving a favourable patient outcome and successful recovery.

Hyperferritinemia in Severe Dengue Infection: Single-Center Retrospective Cohort Study

OBJECTIVES

Hyperferritinemia in the critical phase of dengue infections may correlate with severe dengue ( sd ) disease, and our primary objective was to examine the association between ferritin level on day 1 of PICU admission and 2009 World Health Organization (WHO) criteria for sd . Our secondary objective was outcome in relation to care. It is unclear whether immunomodulatory therapy during the critical phase may restore immune homeostasis and mitigate disease severity.

DESIGN, SETTING, AND PATIENTS

Retrospective cohort study of children with dengue 1 month to 16 years old with admission ferritin greater than or equal to 500 ng/mL requiring PICU admission. Demographics, clinical, and laboratory parameters, presence of the 2009 WHO sd criteria and outcomes were analyzed. Immunomodulatory therapy was used when there was persistent hyperinflammation beyond the critical phase of plasma leakage.

INTERVENTIONS

None.

MEASUREMENTS AND MAIN RESULTS

Fifty-five patients were admitted in the critical phase of dengue with median (interquartile range) ferritin levels of 8,105 ng/mL (2,350-15,765 ng/mL). Patients with at least one WHO sd category had higher ferritin levels compared to those without any sd criteria, with the highest levels in eight patients with all three sd categories. In our cohort of 55, 52 patients (94%) recovered with standard supportive therapy. Recovery was associated with decreased ferritin levels that occurred in parallel with improved circulation and platelet counts; this included 22 of 24 patients with admission ferritin levels greater than or equal to 10,000 ng/mL and two with ferritin greater than 1,00,000 ng/mL. Immunomodulation was used in three patients with unremitting fever, persistent hyperferritinemia, and progressive multiple organ dysfunction beyond the critical phase, of whom two died.

CONCLUSIONS

Hyperferritinemia in the critical phase of sd is associated with the number of 2009 WHO sd criteria present. Our data also indicate that many patients with sd recover well with supportive care.

A Rare Case of Disseminated Histoplasmosis With Hemophagocytic Lymphohistiocytosis Mimicking a Flare of Systemic Lupus Erythematosus in a Middle-Aged Man: A Case Report

Disseminated histoplasmosis is a progressive granulomatous disease caused by Histoplasma capsulatum, which is an intracellular dimorphic fungus endemic to the Ohio and Mississippi River valleys in the United States. It is usually thought to be due to the failure of the activation of the T-cell-mediated immune response. Hemophagocytic lymphohistiocytosis (HLH) is a rare but potentially fatal condition, in which histiocytes and lymphocytes build up in and damage organs and other blood cells. We present a 37-year-old man with a past medical history of systemic lupus erythematosus (SLE) complicated by lupus nephritis on immunosuppressive therapy who presented to the emergency department with hypotension and was admitted for acute kidney injury. Prior to the presentation, he had persistent fever, myalgias, cough, mild shortness of breath, and back pain. Computed tomography (CT) chest shows "eggshell" calcification; microbiology evaluation of peripheral blood smear revealed intracellular organism, morphologically consistent with H. capsulatum; and urine histoplasmosis antigen test confirmed the diagnosis of histoplasmosis. HLH diagnosis was made clinically after "clinical and testing criteria" were evaluated. Despite further management, he developed coagulopathy and sepsis, which led to his death. At autopsy, we found organomegaly of the liver, spleen, and kidneys. Microscopically, these enlarged organs show old fibrotic granulomas and granulomatous inflammation with suspected fungal organisms. Gomori's methenamine silver special stain confirmed these fungal organisms to be consistent with Histoplasma species (3-5 micron budding yeasts). This case highlights that physicians should be aware of the diagnostic challenge that disseminated histoplasmosis with HLH could pose in a patient with SLE, especially in patients on immunosuppression. Failure to recognize the infection promptly could lead to grievous complications and possibly death.

Secondary Hemophagocytic Lymphohistiocytosis: A Series of Three Cases

Hemophagocytic lymphohistiocytosis (HLH) is a disease of abnormal activation of the immune system, either due to a familial cause or a sporadic cause, in relation to various triggering agents. Secondary HLH is a complication of various diseases, such as infections, malignancies, and autoimmune disorders. In our case series, we present three cases of secondary HLH with varied etiologies. Case 1 involved an 18-year-old male with a history of pulmonary tuberculosis, presenting with fever, hepatosplenomegaly, and elevated inflammatory markers. HLH was treated with steroids alongside antitubercular therapy (ATT). In case 2, a 17-year-old male presented with dengue fever, fever, hepatosplenomegaly, and elevated inflammatory markers. HLH was managed with steroids and etoposide. In case 3, a 29-year-old female with systemic lupus erythematosus (SLE) presented with fever, hepatosplenomegaly, and a positive antinuclear antibody (ANA) test. Steroid therapy was initiated for HLH. The prognosis depends on various factors. The management of such cases necessitates expeditious treatment of the underlying disease in conjunction with amelioration of the cytokine storm with the immunosuppressive agents precipitated by the secondary conditions. Once the underlying cause of the cytokine storm is treated, the lethal progression of the disease may come to a halt.

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.

Ebola Virus Disease Features Hemophagocytic Lymphohistiocytosis/Macrophage Activation Syndrome in the Rhesus Macaque Model

BACKGROUND

Ebola virus (EBOV) disease (EVD) is one of the most severe and fatal viral hemorrhagic fevers and appears to mimic many clinical and laboratory manifestations of hemophagocytic lymphohistiocytosis syndrome (HLS), also known as macrophage activation syndrome. However, a clear association is yet to be firmly established for effective host-targeted, immunomodulatory therapeutic approaches to improve outcomes in patients with severe EVD.

METHODS

Twenty-four rhesus monkeys were exposed intramuscularly to the EBOV Kikwit isolate and euthanized at prescheduled time points or when they reached the end-stage disease criteria. Three additional monkeys were mock-exposed and used as uninfected controls.

RESULTS

EBOV-exposed monkeys presented with clinicopathologic features of HLS, including fever, multiple organomegaly, pancytopenia, hemophagocytosis, hyperfibrinogenemia with disseminated intravascular coagulation, hypertriglyceridemia, hypercytokinemia, increased concentrations of soluble CD163 and CD25 in serum, and the loss of activated natural killer cells.

CONCLUSIONS

Our data suggest that EVD in the rhesus macaque model mimics pathophysiologic features of HLS/macrophage activation syndrome. Hence, regulating inflammation and immune function might provide an effective treatment for controlling the pathogenesis of acute EVD.

Epidemiology, characteristics, and outcomes of adult haemophagocytic lymphohistiocytosis in the USA, 2006-19: a national, retrospective cohort study

Background

Haemophagocytic lymphohistiocytosis (HLH) is a rare and life-threatening syndrome characterized by an excessive inflammatory response. Limited data exist on adult HLH.

Methods

In this national, retrospective cohort study, we analysed data from the US National Inpatient Sample database collected between October 1, 2006 and December 31, 2019. Using the International Classification of Diseases (ICD) codes, we identified all adult patients who were admitted non-electively with the diagnosis of HLH. We described demographic characteristics, triggers, and associated conditions. Trends of diagnosis, treatment, and in-hospital mortality were analysed using joinpoint models. In-hospital mortality rates were compared using multivariable logistic regression models that adjusted for demographic characteristics and associated conditions. Finally, we described resource utilization outcomes including cost of hospitalization and length of stay.

Findings

We identified 16,136 non-elective adult HLH admissions. The population pyramid showed a bimodal distribution, with peaks in young adults (16-30 years) and older adults (56-70 years). Joinpoint regression analysis revealed a significant increase in HLH incidence per 100,000 admissions over the study period (Average Annual Percent Change [APC] = 25.3%, p < 0.0001), and no significant change in rates of in-hospital mortality (slope = -0.01; p = 0.95) or administration of in-hospital HLH treatment (slope = 0.46, p = 0.20). The most common associated conditions were malignancy (4953 admissions [30.7%]), infections (3913 admissions [24.3%]), autoimmune conditions (3362 admissions [20.8%]), organ transplant status (639 admissions [4%]), and congenital immunodeficiency syndromes (399 admissions [2.5%]). In-hospital mortality was higher in older adults and males. Furthermore, Congenital immunodeficiency syndromes had the worst in-hospital mortality rate (mortality rate 31.1%, adjusted OR 2.36 [1.56-3.59]), followed by malignancies (mortality rate 28.4%, adjusted OR 1.80 [1.46-2.22]), infections (mortality rate 21.4%, adjusted OR 1.33 [1.10-1.62]), other/no trigger (mortality rate 13.6%, adjusted OR 0.73 [0.58-0.92]), autoimmune (mortality rate 13%, adjusted OR 0.72 [0.57-0.92]), and post-organ transplant status (mortality rate 14.1%, adjusted OR 0.64 [0.43-0.97]). The overall mean length of stay was 14.3 ± 13.9 days, and the mean cost of hospitalization was $54,900 ± 59,800.

Interpretation

We provide insight into the burden of adult HLH in the USA. The incidence has been increasing and the outcomes remain dismal. This signifies the growing need for the development of updated diagnosis and treatment protocols that are specific to adult HLH.

Funding

None.

Complex considerations - Fever and pancytopenia after solid organ transplantation

This case describes a 42-year-old man who underwent kidney transplantation and developed fevers, pancytopenia, and elevated liver function tests starting on post-operative day 9. An extensive microbiologic and molecular workup was performed, ultimately leading to a diagnosis of donor-derived toxoplasmosis with associated hemophagocytic lymphohistiocytosis in the recipient. This case highlights the potential for post-transplant toxoplasmosis in high-risk mismatch (D+/R-) recipients, as well as the role of Toxoplasma-targeted prophylaxis in such patients.

Griscelli Syndrome With Hemophagocytic Lymphohistiocytosis: A Rare Case Report

Griscelli syndrome type 2 (GS2) is a rare, autosomal recessive condition caused by a mutation of the RAB27A gene that causes primary immunodeficiency and pigmentary dilution of skin and hair. It is a rare occurrence, with only 160 cases reported all over the world. It commonly progresses to hemophagocytic lymphohistiocytosis (HLH) due to immunodeficiency. We herein represent the case of a seven-month-old male child, the firstborn of a third-degree consanguineous marriage, who presented with recurrent viral infections and silvery grey hair. A definitive diagnosis of GS 2 was made in accordance with the pathognomonic appearance of hair on microscopic examination and whole genome sequencing, which revealed a homozygous missense mutation in exon 3 of the RAB27A gene. This article is being reported to highlight the rare incidence of this disease, its overlapping clinical features with malnutrition, the challenges faced in diagnosis, and the treatment modalities for it.

Cytokine storm associated with severe COVID-19 infections: The potential mitigating role of omega-3 fatty acid triglycerides in the ICU

Cytokine storm during severe COVID-19 infection increases the risk of mortality in critically ill patients in the intensive care unit. Multiple therapeutic proposals include, for example, anti-inflammatory and immunosuppressive agents, selective inhibitors of key pro-inflammatory receptors, and key enzymes necessary for viral replication. Unfortunately, safe and effective therapy remains an elusive goal. An alternative anti-inflammatory approach vis á vis omega-3 fatty acids, which yields less pro-inflammatory mediators by altering eicosanoid metabolism, has been proposed. Although theoretically promising, enteral tube delivery or oral capsules containing specific doses of omega-3 fatty acids take precious time (7 days to 6 weeks) to be incorporated in plasma cell membranes to be most effective, making this route of administration in the acute care setting an unfeasible therapeutic approach. Parenteral administration of precise doses of omega-3 fatty acid triglycerides in an injectable emulsion can greatly accelerate the incorporation and potential therapeutic effects (within hours), but at present, there is no commercially available product designed for this purpose. We describe a potential formulation that may address this deficiency, while recognizing that the high incidence of hyperlipidemia that occurs during severe COVID-19 infection must be recognized as a complicating factor, and, therefore, caution is advised.

Ehrlichia-Induced Hemophagocytic Lymphohistiocytosis (HLH) With No Response to Doxycycline Treatment

Hemophagocytic lymphohistiocytosis (HLH) is a rare, life-threatening condition characterized by the persistent activation of antigen-presenting cells and multisystemic inflammation. Ehrlichiosis is a tick-born infection that primarily infects the white blood cells and can present with a variety of symptoms, including fever, fatigue, and multisystemic complications. Here, we present a 58-year-old female hospitalized for a urinary tract infection. Her hospital course was complicated by HLH, which was later discovered to be precipitated by an Ehrlichia chaffeensis infection. The patient did not respond to the doxycycline treatment, developed multiorgan failure, and passed away after a few weeks of treatment trials.

Innate and adaptive immunity to SARS-CoV-2 and predisposing factors

The coronavirus disease 2019 (COVID-19) pandemic, caused by severe acute respiratory syndrome coronavirus (SARS-CoV-2), has affected all countries worldwide. Although some symptoms are relatively mild, others are still associated with severe and even fatal clinical outcomes. Innate and adaptive immunity are important for the control of SARS-CoV-2 infections, whereas a comprehensive characterization of the innate and adaptive immune response to COVID-19 is still lacking and the mechanisms underlying immune pathogenesis and host predisposing factors are still a matter of scientific debate. Here, the specific functions and kinetics of innate and adaptive immunity involved in SARS-CoV-2 recognition and resultant pathogenesis are discussed, as well as their immune memory for vaccinations, viral-mediated immune evasion, and the current and future immunotherapeutic agents. We also highlight host factors that contribute to infection, which may deepen the understanding of viral pathogenesis and help identify targeted therapies that attenuate severe disease and infection.

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.

Brain MRI Findings of Hemophagocytic Lymphohistiocytosis With a Heterozygous PRF1 Gene Mutation Masquerading As CLIPPERS: A Case Report

Familial hemophagocytic lymphohistiocytosis is a rare and potentially life-threatening genetic condition characterized by unsuppressed immune activation and hypercytokinemia. Chronic Lymphocytic Inflammation with Pontine Perivascular Enhancement Responsive to Steroids (CLIPPERS) is a central nervous system inflammatory disorder characterized by punctate and curvilinear gadolinium-enhancing lesions in the brainstem, cerebellum, and spinal cord, which responds well to corticosteroid treatment. Hemophagocytic lymphohistiocytosis has been known to mimic CLIPPERS on neuroimaging, and patients previously diagnosed with CLIPPERS may carry familial hemophagocytic lymphohistiocytosis-related gene mutations that serve as predisposing factors. In this article, we describe a case initially diagnosed with CLIPPERS based on characteristic magnetic resonance imaging features and clinical course, who was later diagnosed with hemophagocytic lymphohistiocytosis based on a heterozygous familial hemophagocytic lymphohistiocytosis-associated PRF1 gene mutation.

Hemophagocytic Lymphohistiocytosis Caused by a Severe Epstein-Barr Virus Infection in a Young Patient Presenting With Hiccups

Hemophagocytic lymphohistiocytosis (HLH) is a life-threatening hyperinflammatory syndrome characterized by a pathologic immune response in the setting of infection, malignancy, acute illness, or any immunological stimulus. Infection is the most common etiology of HLH. HLH involves aberrant activation of lymphocytes and macrophages with resultant hypercytokinemia due to an inappropriately stimulated and ineffective immune response. Here, we present the case of a previously healthy 19-year-old male presenting with hiccups and scleral icterus, who was found to have HLH due to a severe Epstein-Barr virus infection. Despite a morphologically normal bone marrow biopsy, the patient met the diagnostic criteria for HLH, including a low natural killer cell count and elevated soluble interleukin-2 receptor. Notably, ferritin was severely elevated at 85,810 ng/mL. The patient was treated with an induction course of dexamethasone intravenously for eight weeks. Since HLH can progress into multi-organ failure, timely diagnosis and prompt initiation of treatment are critical. Novel disease-modifying therapies and further clinical trials are warranted to treat this potentially fatal immunological disease with multisystem ramifications.

Haemophagocytic lymphohistiocytosis in pregnancy and the postpartum period: A retrospective case series analysis

Introduction

Haemophagocytic lymphohistiocytosis (HLH) is an extremely rare condition characterised by excessive immune activation leading to haemophagocytic activity and has seldom been reported in pregnancy. HLH manifests as relapsing fevers with features of multi- organ failure and has a high mortality.

Methods

A retrospective case series analysis using national data from MBRRACE-UK maternal death reports (n=5) and case notes from patients diagnosed with HLH during pregnancy at New Cross Hospital, Wolverhampton (n=2) between 2012 and 2021.

Results

A total of seven cases were included. Cases uniformly presented with fever and experienced prodromal illnesses consisting of lymphadenopathy, fevers, and malaise. Gestation at presentation ranged from 9/40 to 11 months postpartum. All patients had multiple cytopaenias. Other common features included elevated liver enzymes (n=5), hyperferritinaemia (n=5), splenomegaly (n=4), hypofibrinogenemia (n=4) and elevated soluble interleukin-2 receptor α (CD25) levels (n=3). Underlying causes were identified in four cases. Median time from presentation to diagnosis was 35 days. Bone marrow biopsy was diagnostic in a majority of cases. Corticosteroids and ciclosporin were the most frequently used treatments. In some cases early delivery by caesarean section or termination of pregnancy was necessary to permit maternal treatment. Progression to multi-organ failure resulting in maternal death occurred in five cases: two cases survived. Pregnancy outcomes were: livebirth at term (n=2), preterm livebirth (n=3), termination of pregnancy (n=1), and miscarriage (n=1). Of the surviving infants, one had bone marrow suppression with anaemia at birth and sensorineural deafness.

Conclusions

Due to the rarity of the condition, diagnosis is often delayed. In view of the high mortality, clinicians should consider HLH early when reviewing pregnant patients with unexplained pyrexia and multi-organ dysfunction. Early involvement of haematology should be sought, as prompt diagnosis is crucial for meaningful attempts at curative therapy. Important treatment considerations include fetal viability, maternal condition and treatment toxicity.

Treatment and mortality of hemophagocytic lymphohistiocytosis in critically ill children: A systematic review and meta-analysis

OBJECTIVE

Risk factors of mortality in critically ill children with hemophagocytic lymphohistiocytosis (HLH) are not well described. This systematic review aims to determine overall mortality of critically ill children with HLH, and describes etiologies, treatment, and pediatric intensive care unit (PICU) support employed.

DATA SOURCES

PubMed, Embase, Web of Science, CINAHL, and Cochrane Library from inception until February 28, 2022.

STUDY SELECTION

Observational studies and randomized controlled trials reporting children aged 18 years or below, diagnosed with HLH and admitted to the PICU.

DATA EXTRACTION

Etiologies, treatment modalities, PICU therapies, and mortality outcomes were summarized. Random-effects meta-analysis was performed.

DATA SYNTHESIS

Total 36 studies (total patients = 493, mean age: 49.5 months [95% confidence interval (CI): 30.9-79.5]) were included. Pooled mortality rate was 32.6% (95% CI: 23.4-42.4). The most frequent etiologies for HLH were infections (53.3%) and primary HLH (12.8%), while the remaining cases were due to other causes of secondary HLH, including autoimmune diseases, malignancy, and drug-induced and idiopathic HLH. Pooled mortality rate was higher in primary than secondary HLH (72.2%, 95% CI: 57.8-84.5 vs. 23.9%, 95% CI: 14.4-35.02; p < .01). Univariate analysis found that treatment with etoposide was associated with higher mortality, while intravenous immunoglobulins (IVIGs) were associated with lower mortality. Conversely, multivariable analysis adjusted for etiology demonstrated no association between etoposide and IVIG use, and mortality. Twenty-one studies (total patients = 278) had detailed information on PICU therapies. Mechanical ventilation (MV), continuous renal replacement therapy, and inotropes were used in 107 (38.5%), 66 (23.7%), and 51 patients (18.3%), respectively. Need for MV was associated with increased risk of mortality (mean difference = 28%, 95% CI: 9-47).

CONCLUSION

Critically ill children with HLH have high mortality rates and require substantial PICU support. Collaborative work between multiple centers with standardized data collection can potentially provide more robust data.

Mortality and Associated Causes in Hemophagocytic Lymphohistiocytosis: A Multiple-Cause-of-Death Analysis in France

Hemophagocytic lymphohistiocytosis (HLH) is a severe hyperinflammatory syndrome with an overall mortality rate of 40%. A multiple-cause-of-death analysis allows for the characterization of mortality and associated causes over an extended period. Death certificates, collected between 2000 and 2016 by the French Epidemiological Centre for the Medical Causes of Death (CepiDC, Inserm), containing the ICD10 codes for HLH (D76.1/2), were used to calculate HLH-related mortality rates and to compare them with the general population (observed/expected ratios, O/E). HLH was mentioned in 2072 death certificates as the underlying cause of death (UCD, n = 232) or as a non-underlying cause of death (NUCD, n = 1840). The mean age at death was 62.4 years. The age-standardized mortality rate was 1.93/million person-years and increased over the study period. When HLH was an NUCD, the most frequently associated UCDs were hematological diseases (42%), infections (39.4%), and solid tumors (10.4%). As compared to the general population, HLH decedents were more likely to have associated CMV infections or hematological diseases. The increase in mean age at death over the study period indicates progress in diagnostic and therapeutic management. This study suggests that the prognosis of HLH may be at least partially related to coexisting infections and hematological malignancies (either as causes of HLH or as complications).

A young Saudi female with combined hemophagocytic lympho-histiocytosis and Kikuchi's disease: A case report

Kikuchi's disease is an idiopathic self-limiting condition first reported in Japan in 1972. However, hemophagocytic lympho-histiocytosis is a condition that occurs due to overstimulation of the immune system. The presence of the two conditions is rare, and the clinical observation of this unusual clinical syndrome is worth reporting. We are reporting an 18-year-old Saudi female patient who presented with high-grade fever and diaphoresis 3 weeks before her presentation. Physical examination showed palpable cervical and axillary lymphadenopathy; laboratory investigation found neutropenia, a high lactate dehydrogenase of 550 U/L, and high ferritin levels. A thoracoabdominal computed tomographic study revealed generalized lymphadenopathy. She was diagnosed with hemophagocytic lympho-histiocytosis based on a bone marrow biopsy finding and Kikuchi's disease based on an excisional cervical lymph node biopsy. She received a high dose of dexamethasone with complete resolution of the condition. In conclusion, hemophagocytic lympho-histiocytosis and Kikuchi's Disease are uncommon conditions. The presence of a combination of such two conditions is extremely rare and worth reporting. Early diagnosis and initiation of the management with high dexamethasone dose could save patient life.

Prognostic factors in patients with bone marrow hemophagocytosis and its association with hematologic malignancies

Hemophagocytic lymphohistiocytosis (HLH) is a heterogeneous group of hyperinflammatory statuses that are difficult to diagnose and can be life-threatening. Bone marrow (BM) hemophagocytosis is one of the diagnostic criteria according to HLH 2004 diagnostic criteria and HS score. Limited studies have focused on the prognostic factors of BM hemophagocytosis and its association with hematologic malignancies. We aimed to analyze the clinical significance of BM hemophagocytosis. Patients with BM hemophagocytosis, either by cytology or pathology, were enrolled at Taipei Veterans General Hospital from January 2002 to July 2021. Relevant clinical and laboratory data were extracted from medical records. Of 119 patients with BM hemophagocytosis, 57 were diagnosed with hematologic malignancies. The median age of the patients was 58, ranging from 21 to 90. Splenomegaly (adjusted odds ratio [aOR] 2.96; 95% confidence interval [CI] 1.13-7.79) was a risk factor for hematologic malignancies, while autoimmune disease (aOR 0.07; 95% CI 0.01-0.39) and increased D-dimer (aOR 0.25; 95% CI 0.07-0.92) were protective factors. Risk factors for mortality in patients with BM hemophagocytosis were hematologic malignancies (adjusted hazard ratio [aHR] 2.34; 95% CI 1.24-4.44), Eastern Cooperative Oncology Group score ≥3 (aHR 2.42; 95% CI 1.20-4.89) and thrombocytopenia (aHR 3.09; 95% CI 1.04-9.16). In conclusion, among patients with BM hemophagocytosis, splenomegaly was a predictor of hematologic malignancies. Patients with hematologic malignancies, poor performance status, or thrombocytopenia had a higher mortality risk. Further validation studies are warranted.

Hypertriglyceridemia with pancreatitis at disease onset in systemic lupus erythematosus

Systemic lupus erythematosus (SLE) is an autoimmune disease characterised by the presence of several autoantibodies, immune complex formation and multiple organ system involvement. SLE has a wide range of manifestations involving nearly all organ systems. Hypertriglyceridemia (HTG) in SLE is a well-established and a common abnormality, which is generally mild and not included in the diagnostic criteria of SLE. HTG as the initial manifestation of SLE in adult patients in association with acute pancreatitis at levels below 1000 mg/dL has not been previously reported. Here, we report a case of rare presentation of moderate HTG (TG-869 mg/dL) with pancreatitis at disease onset in an adult women which later proved to be due to SLE and progressed to levels of severe HTG during the course of illness. The patient was successfully treated with plasma exchanges and cyclophosphamide.

Hemophagocytic lymphohistiocytosis: a case series analysis in a pediatric hospital

INTRODUCTION

Hemophagocytic lymphohistiocytosis (HLH) is a rare clinical laboratory condition with high mortality rates, resulting from ineffective overactivation of the immune system. Data in the Brazilian literature is scarce, contributing to the challenge in standardizing conducts and performing an early diagnosis of HLH.

OBJECTIVE

To describe the clinical, laboratory, and evolutionary findings on HLH patients treated at a pediatric hospital.

METHODS

This is an observational, cross-sectional and retrospective study on children diagnosed with HLH, hospitalized between 2009 and 2019. The diagnostic criteria were those described in the Histiocyte Society protocol. The authors evaluated HLH patient laboratory tests, myelograms and bone marrow biopsies, clinical characteristics and therapy.

RESULTS

Twenty-three patients were included, 52.2% of whom were males. The age at diagnosis ranged from one to one hundred and eighty months. Four cases were classified as Primary HLH and nineteen, as Secondary HLH. The main triggers were infections and rheumatological diseases. All children had bicytopenia, and 95.4% had hyperferritinemia. Nineteen patients had liver dysfunction, sixteen had neurological disorders and fourteen had kidney injury. Pulmonary involvement was seen in 61.9%, acting as a worse prognosis for death (p = 0.01). Nine patients underwent the immuno-chemotherapy protocol proposed in the HLH 2004. The time to confirm the diagnosis varied from five to eighty days. The lethality found was 56.3%.

CONCLUSIONS

The present study is the most extensive retrospective exclusively pediatric study published in Brazil to date. Despite the limitations, it was possible to demonstrate the importance of discussing HLH as a pediatric emergency.

Ruxolitinib as an Effective Treatment for Hemophagocytic Lymphohistiocytosis Secondary to SARS-Cov-2 Infection: A Case Report

Background

Hemophagocytic lymphohistiocytosis (HLH) is a life-threatening hyperinflammatory syndrome. SARS-CoV-2 infection can induce secondary HLH, as described in previous case reports, but diagnosis and treatment are challenging.

Case Study

We described an older male patient diagnosed with HLH related to previous SARS-CoV-2 infection. Fever was the only clinical manifestation initially but deterioration in clinical condition and laboratory parameters was observed during hospitalization. He responded poorly to classical therapy but was successfully treated with ruxolitinib.

Conclusion

Clinicians should be aware of the possibility of HLH secondary to mild SARS-CoV-2 infection and take timely therapeutic measures to inhibit an inflammatory factor storm. Ruxolitinib is a potential choice for COVID-19 related HLH.

The hyperinflammatory spectrum: from defects in cytotoxicity to cytokine control

Cytotoxic lymphocytes kill target cells through polarized release of the content of cytotoxic granules towards the target cell. The importance of this cytotoxic pathway in immune regulation is evidenced by the severe and often fatal condition, known as hemophagocytic lymphohistiocytosis (HLH) that occurs in mice and humans with inborn errors of lymphocyte cytotoxic function. The clinical and preclinical data indicate that the damage seen in severe, virally triggered HLH is due to an overwhelming immune system reaction and not the direct effects of the virus per se. The main HLH-disease mechanism, which links impaired cytotoxicity to excessive release of pro-inflammatory cytokines is a prolongation of the synapse time between the cytotoxic effector cell and the target cell, which prompts the former to secrete larger amounts of cytokines (including interferon gamma) that activate macrophages. We and others have identified novel genetic HLH spectrum disorders. In the present update, we position these newly reported molecular causes, including CD48-haploinsufficiency and ZNFX1-deficiency, within the pathogenic pathways that lead to HLH. These genetic defects have consequences on the cellular level on a gradient model ranging from impaired lymphocyte cytotoxicity to intrinsic activation of macrophages and virally infected cells. Altogether, it is clear that target cells and macrophages may play an independent role and are not passive bystanders in the pathogenesis of HLH. Understanding these processes which lead to immune dysregulation may pave the way to novel ideas for medical intervention in HLH and virally triggered hypercytokinemia.

Case report: Hemorrhagic fever with renal syndrome presenting as hemophagocytic lymphohistiocytosis

Hemophagocytic lymphohistiocytosis may occur in patients with genetic predisposition and in sporadic cases due to malignancy or infection. We describe a 49-year old man with hemorrhagic fever, type 1 respiratory insufficiency and acute kidney injury. Diagnostic work up showed a hyperinflammatory syndrome, hypertriglyceridemia, hemophagocytosis, very high ferritin and significantly elevated sCD25. The findings were compatible with hemophagocytic lymphohistiocytosis based on the HLH-2004 criteria. Serological testing indentified Puumala virus as the causal pathogen. The patient was successfully treated with pulse corticosteroids, intravenous immunoglobins and supportive therapy.

Late Diagnosis of Disseminated Sporothrix brasiliensis Infection with Bone Marrow Involvement in an HIV-Negative Patient

Sporotrichosis is a fungal disease that causes symptoms similar to those of other infectious and non-infectious diseases, making diagnosis difficult and challenging. Here, we report a case of an HIV-negative patient presenting disseminated sporotrichosis with widespread cutaneous lesions mimicking pyoderma gangrenosum, with bone marrow infection, pancytopenia, and hemophagocytic syndrome. However, all the clinical manifestations and a bacterial coinfection delayed the request for a fungal diagnosis. Therefore, sporotrichosis should always be investigated in patients from endemic areas presenting with widespread cutaneous lesions associated with pancytopenia.

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

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

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

OBJECTIVE

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

STUDY DESIGN

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

RESULTS

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

CONCLUSIONS

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

Development of a screening score for Hemophagocytic Lymphohistiocytosis among pediatric patients with acute infection of Epstein-Barr virus

Background and aims

Deciding when to suspect hemophagocytic lymphohistiocytosis (HLH) and perform diagnostic tests in patients with acute infection of Epstein-Barr virus (EBV) is challenging, given the high prevalence of EBV infection, the life-threatening risk of EBV-HLH, the relatively low incidence of EBV-HLH, and the wide spectrum of disease presentations. The aim of this study was to develop an EBV-HLH screening model for pediatric patients diagnosed with acute infection of EBV.

Methods

An inpatient cohort with 3183 pediatric patients who were diagnosed with active infection of EBV was used to construct and validate the EBV-HLH screening score model. The model parameters were selected from common laboratory parameters using the method of Akaike Information Criterion-optimal selection through cross-validation under logistic regression. Performance of the score was evaluated and compared with the performance of screening methods using the number of cytopenias lineages.

Results

The EBV-HLH screening score has five parameters, including hemoglobin, platelet, neutrophil, albumin, and lactate dehydrogenase. Using a cut-of value of 29, the scoring model had a sensitivity of 89.2% and a specificity of 89.5% in the validation set. The false negative rate, false positive rate, positive predictive value, and negative predictive value in the validation set was 10.8%, 10.5%, 26.8%, and 99.5%, respectively, similar to that of the training set.

Conclusions

With five common laboratory parameters, the EBV-HLH score provides a simple tool to assist the identification of EBV patients who require further evaluation of HLH. Further studies are needed to evaluate the generalizability of the score and optimize the diagnose process for EBV-HLH.

Parvovirus B19-triggered hemophagocytic lymphohistiocytosis in a patient with Crohn’s disease

Background: Hemophagocytic lymphohistiocytosis (HLH) is a life threatening condition caused by inappropriate immune activity. Infection is often the trigger, both in genetically predisposed and in sporadic cases. Although more commonly seen in the paediatric population, patients of all ages can be affected. Case presentation: A 26-year-old male patient with Crohn’s disease, treated with ustekinumab, presented with high fever, epistaxis and anorexia. Laboratory results showed pancytopenia, and a high serum levels of ferritin and LDH. Colonoscopy revealed only mild signs of disease activity. CT-scan showed splenomegaly and multiple lymphadenopathies. Bone marrow aspirate was suggestive for hemophagocytosis. PCR & serology for parvovirus B19 came back positive. Treatment with ustekinumab was temporarily put on hold and supportive care was given. Viral replication decreased and he recovered completely. Conclusion: There is a known association between HLH and Crohn’s disease. This is probably because they are more susceptible to infections with CMV, EBV and parvovirus B19, all known as triggers for HLH. The role of ustekinumab is unclear: did it play a role in the pathophysiological evolution of this primo-infection with parvovirus B19? On the other hand, did it contribute to the rather mild course of the disease, acting as a immunomodulator that works on interleukin-12, a cytokine that plays a role in HLH? Further study is warranted to answer these questions.

Long COVID-19 Liver Manifestation in Children

OBJECTIVES

Severe acute respiratory syndrome coronavirus 2, the novel coronavirus responsible for coronavirus disease (COVID-19), has been a major cause of morbidity and mortality worldwide. Gastrointestinal and hepatic manifestations during acute disease have been reported extensively in the literature. Post-COVID-19 cholangiopathy has been increasingly reported in adults. In children, data are sparse. Our aim was to describe pediatric patients who recovered from COVID-19 and later presented with liver injury.

METHODS

This is a retrospective case series study of pediatric patients with post-COVID-19 liver manifestations. We collected data on demographics, medical history, clinical presentation, laboratory results, imaging, histology, treatment, and outcome.

RESULTS

We report 5 pediatric patients who recovered from COVID-19 and later presented with liver injury. Two types of clinical presentation were distinguishable. Two infants aged 3 and 5 months, previously healthy, presented with acute liver failure that rapidly progressed to liver transplantation. Their liver explant showed massive necrosis with cholangiolar proliferation and lymphocytic infiltrate. Three children, 2 aged 8 years and 1 aged 13 years, presented with hepatitis with cholestasis. Two children had a liver biopsy significant for lymphocytic portal and parenchyma inflammation, along with bile duct proliferations. All 3 were started on steroid treatment; liver enzymes improved, and they were weaned successfully from treatment. For all 5 patients, extensive etiology workup for infectious and metabolic etiologies was negative.

CONCLUSIONS

We report 2 distinct patterns of potentially long COVID-19 liver manifestations in children with common clinical, radiological, and histopathological characteristics after a thorough workup excluded other known etiologies.

Case report and literature review: Hemophagocytic lymphohistiocytosis in a pregnant woman with systemic lupus erythematosus with Syntaxin 11 gene defect

Hemophagocytic lymphohistiocytosis is an extremely rare occurrence during pregnancy. Early recognition of its signs and symptoms is critical for early intervention, and delays in diagnosis may be life-threatening. A 23-year-old nulliparous woman presented with a persistent fever as high as 39°C with bilateral edema of the lower limbs at 24 weeks of gestation. Typical laboratory findings included pancytopenia, high triglycerides, ferritin, transaminases, bilirubin, and hypoproteinemia. Active systemic lupus erythematosus was diagnosed using an autoimmune work-up and a Systemic Lupus Erythematosus Disease Activity Index 2000 score of 17 points. Her bone marrow aspirate revealed prominent hemophagocytosis; hence, HLH was confirmed. Genetic tests showed mutations in Syntaxin 11 mutations. Considering the potential impact of drugs on the fetus, the patient and her family members chose to terminate the pregnancy through medical induction of labor. Afterwards, her condition improved with immunosuppressive therapy.

A Case of Macrophage Activation Syndrome Manifesting as the Initial Presentation of Systemic Lupus Erythematosus

Macrophage activation syndrome (MAS) is a potentially fatal complication of an autoimmune rheumatologic disease characterized by overwhelming inflammation, multiorgan failure, and high mortality if untreated. We report a rare case of a 56-year-old man who presented with fever for three weeks and had a constellation of clinical features and laboratory findings, meeting the diagnostic criteria for systemic lupus erythematosus (SLE) and SLE-associated MAS. He was treated with high dose intravenous corticosteroid and hydroxychloroquine, resulting in resolution of fever and dramatic clinical improvement.

Features of Hemophagocytic Lymphohistiocytosis in Infants With Severe Combined Immunodeficiency: Our Experience From Chandigarh, North India

Background

Hemophagocytic lymphohistiocytosis (HLH) is characterized by uncontrolled and excessive inflammation leading to high mortality. Aetiology of HLH can be primarily due to genetic causes or secondarily due to infections or rheumatological illness. However, rarely T-cell deficiencies like severe combined immunodeficiency (SCID) can develop HLH.

Objective

To describe clinical and laboratory features of SCID cases who developed HLH.

Methods

We collected clinical, laboratory, and molecular details of patients with SCID who developed HLH at our center at Chandigarh, North India.

Results

Of the 94 cases with SCID, 6 were noted to have developed HLH-like manifestations. Male-female ratio was 5:1. Median (inter-quartile range) age of onset of clinical symptoms was 4.25 months (2-5 months). Median (inter-quartile range) delay in diagnosis was 1 month (1-3.5 months). Family history of deaths was seen in 4 cases. Molecular defects in IL2RG were seen in 5 out of 6 cases. Documented infections include disseminated bacillus calmette-guerin (BCG) infection (n=2), blood stream infections (n=3) with Staphylococcal aureus (n=1), Klebsiella pneumonia (n=1), and Pseudomonas aeruginosa (n=1), pneumonia (influenza H1N1 strain, and K. pneumoniae (n=1).

Conclusion

Children with SCID can present with HLH-like manifestations secondary to fulminant infections. A high index of suspicion of SCID is needed in infants who present with HLH who have an associated infection or a suggestive family history. Occurrence of HLH-like manifestations in SCID suggests that T-lymphocytes may not have a significant role in immunopathogenesis of HLH.