Hemophagocytic lymphohistiocytosis-how common and how severe is it as a complication of malaria? Retrospective case series and review of the literature

BACKGROUND

Infection-associated secondary hemophagocytic lymphohistiocytosis (sHLH) is a potentially life-threatening hyperinflammatory condition caused by various infectious diseases. Malaria has rarely been described as trigger. The aim of this study is to collect data on frequency, clinical spectrum, and outcome of sHLH induced by malaria.

METHODS

We collected case numbers on malaria and malaria-associated sHLH from specialized centers in Germany from 2015 to 2022. In addition, we conducted a literature search on published cases of malaria-associated sHLH and systematically analyzed the literature regarding clinical and diagnostic criteria.

RESULTS

We obtained data from 13 centers treating 1461 malaria cases with different Plasmodium species, of which 5 patients (0.34%) also were diagnosed with sHLH. The literature search revealed detailed case reports from further 51 patients and case series comprising the description of further 24 patients with malaria-associated sHLH. Most cases (48/80; 60%) were reported from Asia. The median time interval between onset of malaria symptoms and hospital admission was 7 days. Severe complications of sHLH were documented in 36% (20/56) of patients, including two patients with multiple organ failure in our case series. Only 41% (23/56) of patients received specific treatment for sHLH, nevertheless the mortality rate (CFR) of 5% is lower compared to the CFR reported for sHLH triggered by other infectious diseases (e.g., 25% in sHLH due to EBV infection).

CONCLUSION

Malaria-associated sHLH appears to have a comparatively good prognosis but may still represent an underdiagnosed and potentially fatal complication of malaria, especially in resource-poor settings.

Neonatal hemophagocytic lymphohistiocytosis: A meta-analysis of 205 cases

BACKGROUND

Neonatal hemophagocytic lymphohistiocytosis (nHLH), defined as HLH that presents in the first month of life, is clinically devastating. There have been few large descriptive studies of nHLH.

OBJECTIVES

The objective of this study was to perform a meta-analysis of published cases of nHLH.

METHODS

A comprehensive literature database search was performed. Cases of HLH were eligible for inclusion if clinical analysis was performed at age ≤30 days. Up to 70 variables were extracted from each case.

RESULTS

A total of 544 studies were assessed for eligibility, and 205 cases of nHLH from 142 articles were included. The median age of symptom onset was day of life 3 (interquartile range [IQR]: 0-11, n = 141). Median age at diagnosis was day of life 15 (IQR: 6-27, n = 87). Causes of HLH included familial HLH (48%, n = 99/205), infection (26%, n = 53/205), unknown (17%, n = 35/205), macrophage activation syndrome/rheumatologic (2.9%, n = 4/205), primary immune deficiency (2.0%, n = 5/205), inborn errors of metabolism (2.4%, n = 5/205), and malignancy (2.0%, n = 4/205). Fever was absent in 19% (n = 28/147) of all neonates and 39% (n = 15/38) of preterm neonates. Bicytopenia was absent in 26% (n = 47/183) of patients. Central nervous system (CNS) manifestations were reported in 63% of cases (n = 64/102). Liver injury (68%, n = 91/134) and/or liver failure (24%, n = 32/134) were common. Flow cytometry was performed in 22% (n = 45/205) of cases. Many patients (63%, n = 121/193) died within the period of reporting. Discernable values for HLH diagnostic criteria were reported between 30% and 83% of the time.

CONCLUSIONS

Evaluation of nHLH requires rapid testing for a wide range of differential diagnoses. HLH diagnostic criteria such as fever and bicytopenia may not occur as frequently in the neonatal population as in older pediatric populations. Neurologic and hepatic manifestations frequently occur in the neonatal population. Current reports of nHLH suggest a high mortality rate. Future publications containing data on nHLH should improve reporting quality by reporting all clinically relevant data.

Clinical Efficacy of Programmed Cell Death Ligand 1 Antibody in Treatment of Extranodal Natural Killer/T-Cell Lymphoma With Hemophagocytic Lymphohistiocytosis

Extranodal natural killer/T-cell lymphoma-associated hemophagocytic lymphohistiocytosis (ENKTCL-LAHS) is a rare disease with poor prognosis. Currently, there are no well-established treatments for LAHS. Almost 50% of patients experience relapsed or refractory disease to anti-hemophagocytic lymphohistiocytosis (HLH) treatment, and the regimen for salvage therapy is limited. We report a case of ENKTCL-LAHS that was successfully treated with a programmed cell death ligand 1 (PD-L1) antibody (sugemalimab) alone and provide a literature review on existing ENKTCL-LAHS treatment options. A 31-year-old man with relapsed ENKTCL complicated by HLH was admitted to our hospital. Following the administration of the PD-L1 antibody sugemalimab, fever was resolved, Epstein-Barr virus (EBV) DNA copy number was negative, and HLH-related blood biochemical markers were decreased in the patient. Consequently, the patient achieved complete remission with a progression-free time (PFS) of 44 months. The prognosis of ENKTCL-LAHS is extremely poor, and the clinical treatment of ENKTCL-HLH is challenging. No previous reports exist regarding the use of PD-L1 antibodies in ENKTCL-LAHS treatment. This study is the first to report a patient with ENKTCL-LAHS treated with the PD-L1 antibody alone, who achieved a long PFS of 44 months. Our results suggest the effectiveness and safety of sugemalimab in the treatment of ENKTCL-LAHS; however, more clinical cases are required for validation. The PD-L1 antibody presents a novel treatment option for patients with ENKTCL-LAHS and warrants further clinical promotion.

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.

Novel Presentation of Major Histocompatibility Complex Class II Deficiency with Hemophagocytic Lymphohistiocytosis

PURPOSE

Major histocompatibility complex (MHC) class II deficiency is one of the combined immune deficiency disorders caused by defects in the MHC class II regulatory genes leading to abnormal T cells development and function. Therefore, patients mainly present with increased susceptibility to infections, diarrhea, and failure to thrive. In this report, we present one MHC class II deficient patient with a novel presentation with Hemophagocytic Lymphohistiocytosis (HLH).

METHODS

Immunophenotyping of lymphocyte subpopulations and HLA-DR expression was assess by flow cytometry. Gene mutational analysis was performed by whole exome and Sanger sequencing.

RESULTS

We reported a 7-year-old girl, who was diagnosed at age of 2 years with MHC class II deficiency by genetic testing and flow cytometry. Two years later, she developed disseminated BCGitis which was treated with proper antimicrobial agents. At the age of 7 years, she presented with clinical features fulfilling 6 diagnostic criteria of HLH including evidence of hemophagocytic activity in bone marrow aspiration. Accordingly, the diagnosis of HLH was established and the patient was started on IV Dexamethasone, Anakinra and IVIG. Eventually, patient started to improve and was discharged in good condition. Few months later, the patient was readmitted with severe pneumonia and sepsis leading to death.

CONCLUSION

Patients with MHC class II deficiency might present with disseminated BCGitis especially if the patient has severe T cell lymphopenia. Additionally, this immune defect might be added to the list of inborn errors of immunity that can be complicated with HLH.

Drug Allergy Mimics

When approaching a case of apparent drug allergy, the consulting clinician should consider a broad differential diagnosis. This article presents a series of cases that could be commonly referred to an allergist for assessment as "drug allergy," however, a real diagnosis exists that mandates a different diagnostic and treatment strategy, including a case of inducible laryngeal obstruction, multiple drug intolerance syndrome, viral rash, seizure due to metastatic malignancy, and hemophagocytic lymphohistiocytosis initially diagnosed as drug reaction and eosinophilia with systemic symptoms. The initial misdiagnoses of these patients delayed or interfered with their medical care, emphasizing the importance of accurate diagnoses for the benefit of our patients.

Liver Dysfunction in Adult Hemophagocytic Lymphohistiocytosis: A Narrative Review

Hemophagocytic lymphohistiocytosis (HLH) is a rare, life-threatening condition that has been increasingly recognized in adults and is characterized by a hyperinflammatory state due to immune dysregulation. Its nonspecific presentation, the lack of clinician familiarity given its rarity, and shared clinical features with sepsis and other syndromes can lead to a delay in diagnosis and a poor prognosis. Significant liver function abnormalities as the initial manifestation of HLH are uncommon and can range from mild elevation of aminotransferases to fulminant hepatic failure with high mortality rates. The authors encountered a case of adult HLH mimicking acute viral hepatitis in which a markedly elevated ferritin level led to a prompt diagnosis, early initiation of treatment, and a successful outcome. Clinicians, including gastroenterologists and hepatologists, are often called upon to evaluate patients with abnormal liver tests and may lack experience in the early diagnosis and management of liver dysfunction in the context of HLH. Thus, we expand our reporting to a narrative review of literature which explores the pathogenesis of HLH, challenges associated with its diagnosis, previous reports of liver disease associated with the syndrome, recommended treatments for the familial and adult variations including the role of liver transplantation, and the outcomes of these treatments.

Hemophagocyte morphology and hypertriglyceridemia correlate with diagnosis of hemophagocytic lymphohistiocytosis in patients with bone marrow hemophagocytes

OBJECTIVES

To investigate laboratory and bone marrow findings that can help predict a diagnosis of hemophagocytic lymphohistiocytosis (HLH) for patients who have demonstrated hemophagocytes (HPCs) in the bone marrow.

METHODS

A total of 57 cases from 48 patients with HPCs present on bone marrow examination were included. The numbers and morphologic characteristics of HPCs with ingested nucleated cells (nHPC) were counted. Pertinent medical history, relevant laboratory values, and flow cytometry data at the time of bone marrow biopsy were collected.

RESULTS

A total of 24 patients fulfilled diagnostic criteria for HLH, and the remaining 24 patients did not. By using HLH-2004 cutoffs, only hypertriglyceridemia (≥265 mg/dL) was significantly associated with HLH diagnosis. The HLH cases more frequently had nHPC-ingesting granulocytic cells (gHPC) (75.9% vs 24.1%, P = .009). The percentage of gHPC to all nHPC was also significantly higher in HLH cases (median, 15.4% vs 0%; P = .0002). Both triglyceride level (area under the curve [AUC]  = 0.88, P < .0001) and gHPC percentage (AUC = 0.81, P = .0005) were significant in predicting HLH diagnosis. Finally, no overt immunophenotypic abnormality was noted for 19 HLH cases with available flow cytometry data.

CONCLUSIONS

The presence of hypertriglyceridemia and more frequent gHPC has predictive value for HLH diagnosis in patients with bone marrow HPC.

Heartland Virus Disease-An Underreported Emerging Infection

First recognized 15 years ago, Heartland virus disease (Heartland) is a tickborne infection contracted from the transmission of Heartland virus (HRTV) through tick bites from the lone star tick (Amblyomma americanum) and potentially other tick species. Heartland symptoms include a fever <100.4 °F, lethargy, fatigue, headaches, myalgia, a loss of appetite, nausea, diarrhea, weight loss, arthralgia, leukopenia and thrombocytopenia. We reviewed the existing peer-reviewed literature for HRTV and Heartland to more completely characterize this rarely reported, recently discovered illness. The absence of ongoing serosurveys and targeted clinical and tickborne virus investigations specific to HRTV presence and Heartland likely contributes to infection underestimation. While HRTV transmission occurs in southern and midwestern states, the true range of this infection is likely larger than now understood. The disease's proliferation benefits from an expanded tick range due to rising climate temperatures favoring habitat expansion. We recommend HRTV disease be considered in the differential diagnosis for patients with a reported exposure to ticks in areas where HRTV has been previously identified. HRTV testing should be considered early for those matching the Heartland disease profile and nonresponsive to initial broad-spectrum antimicrobial treatment. Despite aggressive supportive therapy, patients deteriorating to sepsis early in the course of the disease have a very grim prognosis.

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

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

Clinical characteristics of hemophagocytic lymphohistiocytosis

BACKGROUND

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

OBJECTIVE

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

METHODS

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

RESULTS

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

CONCLUSION

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

Case Report: Successful avoidance of etoposide for primary hemophagocytic lymphohistiocytosis-induced multiple organ dysfunction syndrome using emapalumab

We describe the case of an infant who presented with simple rhinovirus/enterovirus bronchiolitis whose condition worsened with rapid progression to multiple organ dysfunction syndrome (MODS). The patient was presumed to have either primary or secondary hemophagocytic lymphohistiocytosis (HLH), and treatment was initiated using dexamethasone, anakinra, and intravenous immunoglobulin to modulate the immune system. Due to the organ dysfunction, the use of etoposide was avoided and instead, emapalumab, an interferon gamma antagonist, was administered at a dose of 6 mg/kg. The patient's organ failure improved, and the levels of inflammatory markers decreased. The flow cytometry analysis revealed that cytotoxic cells lacked perforin expression, and subsequent genetic analysis confirmed homozygous pathogenic mutations in the perforin gene. This case highlights the potential avoidance of etoposide in cases of primary HLH, the possible benefit of an elevated initial dose of emapalumab, and the contribution offered by a multi-specialty team approach to complex diagnosis.

[Hemophagocytic lymphohistiocytosis: A retrospective analysis of 66 patients]

CONTEXT

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

METHODS

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

RESULTS

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

DISCUSSION

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

Cytophagic Histiocytic Panniculitis Presenting as Subcutaneous Nodules and Generalized Edema - A Case Report

Background

Cytophagic histiocytic panniculitis (CHP) is a rare form of nodular panniculitis characterized by clinical manifestations such as skin erythema, nodules, fever, pancytopenia, liver failure, plasmacytosis, and hepatosplenomegaly. We report a case of CHP that was initially misdiagnosed as subcutaneous panniculitis-like T-cell lymphoma (SPTCL) but achieved complete remission with a favorable prognosis.

Methods

A 38-year-old female presented to the dermatology department with a 15-day history of subcutaneous nodules, generalized edema, and continuous fever.

Results

The patient was diagnosed as CHP combined with hemophagocytic syndrome by typical clinical manifestations, low value of SUVmax in positron emission tomography/computed tomography (PET/CT), benign differentiated T cells, negative TCR gene rearrangement, pancytopenia, abnormal coagulation, hypertriglyceridemia, decreased NK cell count, impaired liver function, and the presence of hemophagocytic cells observed in bone biopsy smears.

Conclusion

In our case, the patient presented with hemophagocytic syndrome with hemodynamic instability, indicating an intensive treatment is needed. The diagnosis of SPTCL necessitates a meticulous process of differential diagnosis, along with the cautious administration of an aggressive chemotherapy regimen. Extended follow-up is imperative to ascertain the long-term outcomes.

Successful use of subcutaneous anakinra in hemophagocytic lymphohistiocytosis precipitated by candidiasis in a patient with systemic lupus erythematosus: A case report and description of a novel therapeutic regimen

Hemophagocytic lymphohistiocytosis (HLH) is a rare and often fatal condition characterized by inappropriate immune system activation leading to a "cytokine storm", and ultimately resulting in end-organ damage. Causes include primary defects in genes involved in immune-mediated cytolytic pathways, or secondary triggers such as infection or malignancy. We describe a case of HLH precipitated by fungal infection which occurred as a consequence of immunosuppression for management of systemic lupus erythematosus (SLE) and necrotizing myopathy. The patient presented with immune-mediated disease of the muscles and lung which was treated with high-dose corticosteroids and aggressive immunosuppression. HLH emerged in the context of confirmed candidiasis and features of severe sepsis. The patient responded rapidly to antifungal therapy and high-dose anakinra, which was administered subcutaneously and progressively weaned over 4 weeks. She completed HLH treatment as an outpatient and remains well at 12 months with controlled SLE and no recurrence of HLH.

Predictive model for early death risk in pediatric hemophagocytic lymphohistiocytosis patients based on machine learning

Background

Hemophagocytic Lymphohistiocytosis (HLH) is a rare and life-threatening disease in children, with a high early mortality rate. This study aimed to construct machine learning model to predict the risk of early death using clinical indicators at the time of HLH diagnosis.

Methods

This observational cohort study was conducted at the National Clinical Research Center for Child Health and Disease. Data was collected from pediatric HLH patients diagnosed by the HLH-2004 protocol between January 2006 and December 2022. Six machine learning models were constructed using the Least Absolute Shrinkage and Selection Operator (LASSO) to select key clinical indicators for model construction.

Results

The study included 587 pediatric HLH patients, and the early mortality rate was 28.45 %. The logistic and XGBoost model with the best performance after feature screening were selected to predict early death of HLH patients. The logistic model had an AUC of 0.915 and an accuracy of 0.863, while the XGBoost model had an AUC of 0.889 and an accuracy of 0.829. The risk factors most associated with early death were the absence of immunochemotherapy, decreased TC levels, increased BUN and total bilirubin, and prolonged TT. We developed an online calculator tool for predicting the probability of early death in children with HLH.

Conclusions

We developed the first web-based early mortality prediction tool for pediatric HLH to assist clinicians in risk stratification at diagnosis and in developing personalized treatment protocols. This study is registered on the China Clinical Trials Registry platform (ChiCTR2200061315).

Clinical Symptoms, Laboratory Parameters and Long-Term Follow-up in a National DADA2 Cohort

Deficiency of adenosine deaminase-2 (DADA2) is an autosomal recessive autoinflammatory disease with an extremely variable disease presentation. This paper provides a comprehensive overview of the Dutch DADA2 cohort. We performed a retrospective cohort study in 29 ADA2-deficient patients from 23 families with a median age at inclusion of 26 years. All patients had biallelic pathogenic variants in the ADA2 gene. The most common clinical findings included cutaneous involvement (79.3%), (hepato)splenomegaly (70.8%) and recurrent infections (58.6%). Stroke was observed in 41.4% of the patients. The main laboratory abnormalities were hypogammaglobulinemia and various cytopenias. Patients presented most often with a mixed phenotype involving vasculopathy, immunodeficiency and hematologic manifestations (62.1%). In this cohort, malignancies were reported in eight patients (27.6%), of whom five presented with a hematologic malignancy and two with a basal cell carcinoma. Four patients developed hemophagocytic lymphohistiocytosis (HLH) or an HLH-like episode, of whom three passed away during or shortly after the occurrence of HLH. TNF-inhibitors (TNFi) were effective in treating vasculopathy-associated symptoms and preventing stroke, but were hardly effective in the treatment of hematologic manifestations. Three patients underwent hematopoietic cell transplantation and two of them are doing well with complete resolution of DADA2-related symptoms. The overall mortality in this cohort was 17.2%. In conclusion, this cohort describes the clinical, genetic and laboratory findings of 29 Dutch DADA2 patients. We describe the occurrence of HLH as a life-threatening disease complication and report a relatively high incidence of malignancies and mortality.

Hemophagocytic lymphohistiocytosis secondary to unrecognized Bartonella henselae infection: a case report

BACKGROUND

Bartonella henselae is a species of intracellular bacteria transmitted to humans through animal bites and scratches contaminated with the feces of arthropod vectors, and are most commonly associated with cat exposure although transmission from other mammals has been reported. Bartonella henselae infection has a spectrum of clinical manifestations and has rarely been reported as cause of hemophagocytic lymphohistiocytosis (HLH) in immunocompromised hosts.

CASE PRESENTATION

We present a report of Bartonella henselae infection progressing to HLH in an immunocompetent patient. The patient initially presented with regional lymphadenopathy but the diagnosis was not suspected as the patient reported no exposure to cats. On further history, he did report a scratch from a dog prior to development of symptoms. The patient was treated with methylprednisolone, intravenous immunoglobulin and anakinra for the HLH and three months of Doxycycline for Bartonella infection, with complete resolution of symptoms.

CONCLUSIONS

Although commonly associated with cat exposure, Bartonella henselae transmission can occur after exposure to other animals and vectors including dogs and clinicians need to maintain an index of suspicion for timely diagnosis. Bartonella henselae is associated with a spectrum of clinical manifestations which can include disseminated infection with severe complications such as hemophagocytic lymphohistiocytosis. Prompt initiation of Bartonella treatment is essential when thought to be the trigger for hemophagocytic lymphohistiocytosis although the optimal treatment regimen is unclear.

Hemophagocytic Lymphohistiocytosis and Pancreatic Cancer: A Rare Association

Introduction

Hemophagocytic lymphohistiocytosis (HLH) or hemophagocytic syndrome (HPS) is a life-threatening and relatively rare condition that usually presents as a multisystem febrile illness. It is associated with excessive activation of the immune system and hypercytokinemia, leading to an unregulated aggregation of macrophages and lymphocytes. Here, we present the first likely case of HLH with metastatic pancreatic carcinoma being the underlying etiology.

Case

A 44-year-old male with past medical history significant for heart transplant for which he was on tacrolimus, End-Stage Renal Disease (ESRD) on hemodialysis, recently treated CMV viremia, and necrotizing pancreatitis presented to the emergency with complaints of chills, decreased appetite, worsening non-bloody emesis, and dull left upper quadrant abdominal pain with radiation to the back for four days. No shortness of breath, fever, diarrhea, or blood in the stool was reported. Vitals on admission were blood pressure of 90/61 mmHg, a heart rate of 110 beats per minute, temperature of 98.1 °F, and respiratory rate of 18 per minute. Physical exam was significant for scleral icterus, decreased bibasilar breath sounds, moderate abdominal tenderness in the left flank and left upper abdominal quadrant without any palpable mass, and 1+ bilateral pedal edema. The remainder of the physical examination was benign. Electrocardiogram (EKG) showed sinus tachycardia without any ischemic changes, and chest x-ray showed mild pulmonary edema. Initial blood workup revealed WBC at 8.3 k/uL, hemoglobin of 10.2 g/dL, platelet count of 90 k/uL, and BUN/creatinine of 45/5.8 (baseline 40/5.0). Cardiac workup showed an elevated high sensitivity troponin level of 2479 pg/mL and brain natriuretic peptide (BNP) of 600 (0-100 pg/mL). The hepatobiliary profile showed an aspartate transaminase (AST) level of 2645 U/L, an alanine transaminase (ALT) of 2935 U/L, alkaline phosphatase (ALP) of 106 U/L, and lipase of 61 U/L, with total and conjugated bilirubin of 3.5 mg/dL and 2.1 mg/dL, respectively. Transthoracic echocardiogram (TTE) showed reduced left ventricular size with hyperdynamic systolic function. Computerized tomography (CT) scan of the abdomen (Fig. 1) revealed numerous new pulmonary nodules, ring-enhancing lesions within the liver, hyperenhancement of the pancreas with walled-off necrosis, and splenomegaly. Microbiological work-up was positive for cytomegalovirus (CMV) serologies (IgM and IgG) but absent viral load on Polymerase Chain Reaction (PCR). The initial diagnosis was systemic inflammatory respiratory syndrome (SIRS), likely septic versus distributive in the setting of pancreatitis, demand mediated non-ST segment elevation myocardial infarction (NSTEMI), and shock liver. Tacrolimus was held, and the patient was started on broad-spectrum antibiotics including vancomycin and cefepime for sepsis of unknown origin along with vasopressors for hypotension, requiring admission to the medical intensive care unit. Blood and urine cultures were collected on admission which remained negative throughout the course of hospital. CA19-9 levels were found elevated at 5587 U/mL. Liver biopsy was consistent with poorly differentiated adenocarcinoma of pancreatic origin. Both Infectious Disease and Hematology were consulted due to broad differential diagnoses. Due to the patient's continued hemodynamic instability and nonresponsiveness to the antibiotics, HLH was suspected with supporting labs as follows: ferritin 55,740 ng/mL (22-322 ng/mL), triglycerides 177 mg/dL (30-150 mg/dL), and fibrinogen 244 mg/dL (173-454 mg/dL), thus conferring 70-80% probability of HPS based on H-score. Soluble IL-2 R levels came out at 19,188 pg/mL (ref range 175-858 pg/mL). The patient couldn't be started on HLH treatment due to initial concerns of underlying infection and the delay in results of soluble IL-2 Receptor (IL-2 R) levels. The infection as a possible etiology was ruled out due to negative blood and urine cultures and HLH was attributed to pancreatic cancer. A marrow biopsy couldn't be pursued as the patient died within a week of hospitalization. An autopsy was not performed as per family's request.

Conclusion

HLH can occur secondary to solid cell malignancies including those from the pancreas and should be kept high in the differential in critically ill cancer patients who are nonresponsive to antibiotics. H-score has been reported to be a more sensitive tool compared to the HLH protocol, especially if used earlier during the presentation. Further research is needed to compare diagnostic efficacy for HLH protocol verses H-score especially in critically ill patients as they might benefit from steroid trial.

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.

Wolman disease presenting with hemophagocytic lymphohistiocytosis syndrome and a novel LIPA gene variant: a case report and review of the literature

BACKGROUND

Wolman disease is a rare disease caused by the absence of functional liposomal acid lipase due to mutations in LIPA gene. It presents with organomegaly, malabsorption, and adrenal calcifications. The presentations can resemble hemophagocytic lymphohistiocytosis, the life threatening hyperinflammatory disorder. Since the disease is very rare, clinicians might not think of it when a patient presents with hemophagocytic lymphohistiocytosis, and the opportunity to treat it properly can be lost, thus leading to demise of the child.

CASE PRESENTATION

We present a 4.5-month-old Caucasian boy with fever, icterus, and hepatosplenomegaly who was treated according to presumed hemophagocytic lymphohistiocytosis disease. Wolman disease was diagnosed after the death of the child. There are some case reports in the literature presenting patients with Wolman disease primarily diagnosed as hemophagocytic lymphohistiocytosis, which we discuss in this review. The genetic analysis revealed after his demise was compatible with Wolman disease, introducing a novel mutation in LIPA gene: exon 4: NM_001127605: c. G353A (p.G118D), which converts the glycine amino acid to aspartic acid.

CONCLUSIONS

Considering the similarities in presentation of Wolman disease and hemophagocytic lymphohistiocytosis, the patient's life can be saved if special attention is paid to presenting features of a patient with suspected hemophagocytic lymphohistiocytosis, that is special attention to symptoms, findings on physical exams, laboratory values, and radiologic findings, and the proper treatment is urgently initiated. Reporting the novel mutations of Wolman disease can help geneticists interpret the results of their patients' genetic studies appropriately, leading to correct diagnosis and treatment.

An analysis of reported cases of hemophagocytic lymphohistiocytosis (HLH) after COVID-19 vaccination

Although COVID-19 vaccines are an effective public health tool to combat the global pandemic, serious adverse events, such as hemophagocytic lymphohistiocytosis (HLH), caused by them are a concern. In this systematic review, cases of HLH reported after COVID-19 vaccination have been examined to understand the relationship between the two and propose effective therapeutic strategies. Furthermore, ruxolitinib's potential as a cytokine inhibitor and its affinity for CD25 were initially assessed through molecular docking, aiming to aid targeted HLH therapy. PubMed and Web of Science databases were searched for published individual case reports on the occurrence of HLH after the administration of any COVID-19 vaccine. A total of 17 articles (25 patients) were included in this qualitative analysis. Furthermore, molecular docking was employed to investigate the therapeutic potential of ruxolitinib for HLH after COVID-19 vaccination. The mean age of patients who developed HLH after COVID-19 vaccination was 48.1 years. Most HLH episodes occurred after the BNT162b2 mRNA COVID-19 vaccination (14/25 cases) and to an extent after the ChAdOx1 nCov-19 vaccination (5/25 cases). Almost all affected patients received steroid and antibiotic therapy. Three patients died despite treatment because of esophagus rupture, neutropenic fever, bacteroides bacteremia, refractory shock, and encephalopathy and shock. Visual docking results of IL-2 Rα and ruxolitinib using the Discovery Studio 2019 Client software yielded a model score of 119.879. The findings highlight the importance of considering and identifying the adverse effects of vaccination and the possibility of using ruxolitinib for treating HLH after COVID-19 vaccination.

Hyperinflammatory syndrome in a paediatric patient with a recent diagnosis of HIV/AIDS infection: hemophagocytic lymphohistiocytosis or immune reconstitution syndrome?

INTRODUCTION

Haemophagocytic lymphohistiocytosis is a rare and life-threatening condition caused by uncontrolled immune activation leading to excessive inflammation and tissue destruction. It could either be due to a primary genetic defect or be triggered by secondary causes such as infections, autoimmune diseases, rheumatological diseases or post-transplant immunosuppression. We here report the case of a 4-year-old child with a recent AIDS diagnosis who developed a severe systemic inflammation.

CASE REPORT

We here report the case of a 4-year-old child with a recent AIDS diagnosis who was admitted to the ER with acute respiratory failure due to Pneumocystis jiroveci infection and Aspergillosis; the following microbiological assessment also showed a CMV, HSV, EBV and HHV-7 coinfection. On the 51st day after she'd started antiretroviral therapy, 39th after she'd followed a course of Bactrim and Caspofungin for PJI and Ambisome for pulmonary Aspergillosis, she started presenting fever, unresponsive to broad-spectrum antibiotic therapy. She also presented worsening of her clinical conditions, with evidence at the laboratory assessments of progressive raise in inflammatory indexes, coagulopathy, trilinear cytopenia and hyperferritinemia. To perform the differential diagnosis between IRIS and HLH, HLA-DR on T cells was studied, turning out negative for IRIS. Therefore, in the suspicion of HLH, a bone marrow aspirate and biopsy were performed with evidence of trilinear cytopenia, prevalence of T-cells and macrophages with signs of phagocytosis. She was started on high-dose steroids and Anakinra for a total of 29 days, resulting in prompt apyrexia and progressive improvement of her clinical conditions and laboratory results.

CONCLUSION

To the best of our knowledge there is poor literature available about the differential diagnosis of HLH and IRIS, therefore medical management in the concurrence of these two conditions needs to be further investigated, especially in a setting where immunological testing is not quickly available. The clinical differences between these pathologies are blurred and the bone marrow biopsy within marker for IRIS helped us to distinguish these two entities.

Infections Associated Hemophagocytosis-Secondary HLH Mimics in Children!"

Infection-associated hemophagocytosis is a diagnostic challenge. The varied presentation makes timely diagnosis difficult. We report two cases with unusual presentation of well-established secondary triggers for hemophagocytic lymphohistiocytosis.

Intravenous anakinra for the treatment of haemophagocytic lymphohistiocytosis/macrophage activation syndrome: A systematic review

BACKGROUND

Haemophagocytic lymphohistiocytosis (HLH) or macrophage activation syndrome (MAS) has a potentially high mortality rate. Anakinra, an interleukin-1 receptor antagonist, is now recommended early in HLH/MAS, with intravenous (IV) use proposed in critically unwell patients. This systematic review establishes the literature relating to IV anakinra in secondary HLH/MAS (sHLH/MAS).

METHODS

We screened Embase, PubMed, and Medline, including all reports of IV anakinra for HLH or MAS. We extracted age, HLH/MAS trigger, continuous infusion or bolus dosing, and survival.

RESULTS

Twenty-nine case reports/series identified 87 patients (median age 22 years, range 22 months to 84 years), all with sHLH. Amongst identifiable triggers, 43% were systemic infection, 33% rheumatological, 9% oncological. Children had predominantly a rheumatological trigger (48%), whilst adults were more commonly infection-driven (50%). Overall, rheumatologically triggered disease showed greater survival (83.3%), particularly compared with oncological triggers (42.9%). Children had a greater survival, particularly under 10 years (83%, vs. adults, 63%).

CONCLUSIONS

Despite IV anakinra recipients likely to be critically unwell, this cohort had similar disease triggers and survival compared to large historical cohorts, and enhances awareness of age and trigger-specific survival patterns. IV anakinra had a wide therapeutic dosing range and tolerability, regardless of trigger, demonstrating substantial utility in severe sHLH/MAS.

1-year survival in haemophagocytic lymphohistiocytosis: a nationwide cohort study from England 2003-2018

Haemophagocytic lymphohistiocytosis (HLH) is a lethal syndrome of excessive immune activation. We undertook a nationwide study in England of all cases of HLH diagnosed between 2003 and 2018, using linked electronic health data from hospital admissions and death certification. We modelled interactions between demographics and comorbidities and estimated one-year survival by calendar year, age group, gender and comorbidity (haematological malignancy, auto-immune, other malignancy) using Cox regression. There were 1628 people with HLH identified. Overall, crude one-year survival was 50% (95% Confidence interval 48-53%) which varied substantially with age (0-4: 61%; 5-14: 76%; 15-54: 61%; > 55: 24% p < 0.01), sex (males, 46%, worse than females, 55% p < 0.01) and associated comorbidity (auto-immune, 69%, haematological malignancy 28%, any other malignancy, 37% p < 0.01). Those aged < 54 years had a threefold increased risk of death at 1-year amongst HLH associated with malignancy compared to auto-immune. However, predicted 1-year survival decreased markedly with age in those with auto-immune (age 0-14, 84%; 15-54, 73%; > 55, 27%) such that among those > 55 years, survival was as poor as for patients with haematological malignancy. One-year survival following a diagnosis of HLH varies considerably by age, gender and associated comorbidity. Survival was better in those with auto-immune diseases among the young and middle age groups compared to those with an underlying malignancy, whereas in older age groups survival was uniformly poor regardless of the underlying disease process.

A rare case of hemophagocytic lymphohistiocytosis mimicking flare of systemic lupus erythematosus

The Ohio and Mississippi River Valleys are endemic to histoplasmosis. It is usually self-limiting in immunocompetent people, but it can cause morbidity and mortality if not detected early in people with an underlying autoimmune disease. Disseminated Histoplasmosis induced hemophagocytic lymphohistiocytosis (HLH) mimicking the flare of an underlying autoimmune disease, is uncommon in the published literature. Disseminated histoplasmosis (DH) can cause multiorgan involvement, especially in a patient with an underlying autoimmune disease. We present the case of a 24-year-old female with HLH who was initially treated as a flare of autoimmune disease but later etiology was confirmed as disseminated histoplasmosis on bone marrow histopathological examination.

Identification and Characterization of PRE Genes in Moso Bamboo (Phyllostachys edulis)

Basic helix-loop-helix (bHLH)/HLH transcription factors are involved in various aspects of the growth and development of plants. Here, we identified four HLH genes, PePRE1-4, in moso bamboo plants that are homologous to Arabidopsis PRE genes. In bamboo seedlings, PePRE1/3 were found to be highly expressed in the internode and lamina joint by using quantitative RT-PCR analysis. In the elongating internode of bamboo shoots, PePRE genes are expressed at higher levels in the basal segment than in the mature top segment. Overexpression of PePREs (PePREs-OX) in Arabidopsis showed longer petioles and hypocotyls, as well as earlier flowering. PePRE1 overexpression restored the phenotype due to the deficiency of AtPRE genes caused by artificial micro-RNA. PePRE1-OX plants showed hypersensitivity to propiconazole treatment compared with the wild type. In addition, PePRE1/3 but not PePRE2/4 proteins accumulated as punctate structures in the cytosol, which was disrupted by the vesicle recycling inhibitor brefeldin A (BFA). PePRE genes have a positive function in the internode elongation of moso bamboo shoots, and overexpression of PePREs genes promotes flowering and growth in Arabidopsis. Our findings provided new insights about the fast-growing mechanism of bamboo shoots and the application of PRE genes from bamboo.

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

BACKGROUND

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

CASE PRESENTATION

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

CONCLUSIONS

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

Hypocomplementemic urticarial vasculitis case with hemophagocytic lymphohistiocytosis following SARS-CoV-2 mRNA vaccination

A 61-year-old man with no previous record of autoimmune disease developed fever, polyarthralgia, purpura, and urticaria-like rash 2 weeks after the first dose of the Moderna mRNA-1273 vaccine, and symptoms deteriorated following the second dose. He presented reduced erythrocyte and platelet counts, hyperferritinemia, high sIL-2R levels, and severe hypocomplementemia. We diagnosed hypocomplementemic urticarial vasculitis (HUVS), and his symptoms as well as laboratory findings improved following treatment with mPSL 1000 mg/day for 3 days and PSL 40 mg/day. Twelve weeks following treatment initiation, the patient relapsed with fever, sore throat, pancytopenia, and hyperferritinemia when the PSL dose was reduced to 12.5 mg/day. Bone marrow biopsy and MRI presented fatty marrow and hemophagocytosis. The patient's blood cells started recovering using ATG + CsA + EPAG therapy for hemophagocytic lymphohistiocytosis (HLH). This is the first case report of HUVS and HLH following SARS-CoV-2 mRNA vaccination. It is presumed that SARS-CoV-2 mRNA vaccine can induce the excessive production of certain types of cytokines, such as TNF-α, IL-1, IL-4, IL-5, IL-6, and IL-17 as a consequence of IL-6 Amplification (IL-6 Amp). SARS-CoV-2 mRNA-vaccines can cause disruption of immune homeostasis in healthy individuals. An extremely rare disease of HUVS complicated by HLH can be developed as a consequence.

An Unusual Case of Hemophagocytic Lymphohistiocytosis Associated with Mycobacterium chimaera or Large-Cell Neuroendocrine Carcinoma

Hemophagocytic lymphohistiocytosis (HLH) is a rare and very dangerous condition characterized by abnormal activation of the immune system, causing hemophagocytosis, inflammation, and potentially widespread organ damage. The primary (genetic) form, caused by mutations affecting lymphocyte cytotoxicity, is most commonly seen in children. Secondary HLH is commonly associated with infections, malignancies, and rheumatologic disorders. Most current information on diagnosis and treatment is based on pediatric populations. HLH is a disease that should be diagnosed and treated promptly, otherwise it is fatal. Treatment is directed at treating the triggering disorder, along with symptomatic treatment with dexamethasone and etoposide. We present a 56-year-old patient who was admitted with worsening weakness, exertional dyspnea, dry and nonproductive cough, and a 5-pound weight loss associated with loss of appetite. This is among the rare disorders that are not commonly encountered in day-to-day practice. Our differential diagnoses were broad, including infection, such as visceral leishmaniasis, atypical/tuberculous mycobacteria, histoplasmosis, Ehrlichia, Bartonella, Brucella, Adenovirus, disseminated herpes simplex virus (HSV), hematological-like Langerhans cell histiocytosis, or multicentric Castleman disease; drug reaction, such as drug rash with eosinophilia and systemic symptoms (DRESS); and metabolic disorder, including Wolman's disease (infantile lysosomal acid lipase deficiency) or Gaucher's disease. Based on our investigations as described in our case report, it was narrowed down to hemophagocytic lymphohistiocytosis and COVID-19. Two COVID-19 tests were negative. His lab abnormalities and diagnostic testing revealed hemophagocytic lymphohistiocytosis. He was empirically started on antibiotics and dexamethasone, to be continued for 2 weeks then tapered if the patient showed continued improvement. Dexamethasone was tapered over 8 weeks. He improved on just one of the Food and Drug Administration (FDA)-approved medications, proving that treatment should be tailored to the patient. In addition, in this case study, we included the background, etiology, pathogenesis, diagnosis, management, and prognosis of HLH.

Diagnosis and Management of Adult Malignancy-Associated Hemophagocytic Lymphohistiocytosis

Hemophagocytic lymphohistiocytosis (HLH) is a syndrome of severe, dysregulated inflammation driven by the inability of T cells to clear an antigenic target. When associated with malignancy (mHLH), the HLH syndrome is typically associated with extremely poor survival. Here, we review the diagnosis of secondary HLH (sHLH) syndromes in adults, with emphasis on the appropriate workup and treatment of mHLH. At present, the management of HLH in adults, including most forms of mHLH, is based on the use of corticosteroids and etoposide following the HLH-94 regimen. In some cases, this therapeutic approach may be cohesively incorporated into malignancy-directed therapy, while in other cases, the decision about whether to treat HLH prior to initiating other therapies may be more complicated. Recent studies exploring the efficacy of other agents in HLH, in particular ruxolitinib, offer hope for better outcomes in the management of mHLH. Considerations for the management of lymphoma-associated mHLH, as well as other forms of mHLH and immunotherapy treatment-related HLH, are discussed.

CD38high/HLA-DR+ CD8+ T cells as potential biomarker of hemophagocytic lymphohistiocytosis secondary to visceral Leishmania infection

Leishmaniasis is a cause of infection associated with hemophagocytic lymphohistiocytosis (HLH). The measurement of the CD8⁺ CD38^high/HLA-DR⁺ T cells in children presenting with acute onset of shock and multisystem organ failure represents an important parameter to distinguish HLH from sepsis or healthy control.

CONCLUSION

We report a case series of 4 Italian children suffering from HLH secondary to visceral Leishmaniasis in which the lymphocyte subset assay suggests a potential role of CD38^high/HLA-DR⁺ CD8⁺ T cells as HLH diagnostic biomarkers.

WHAT IS KNOWN

• Visceral Leishmaniasis is a well-known cause of infection associated with hemophagocytic lymphohistiocytosis (HLH). • The measurement of the CD8⁺ CD38^high/HLA-DR⁺ T cells in children presenting with acute onset of shock and multisystem organ failure represents an important diagnostically useful parameter to readily distinguish HLH from sepsis or healthy controls.

WHAT IS NEW

• We report a case series of 4 Italian children suffering from HLH secondary to visceral Leishmaniasis in which the lymphocyte subset assay suggests a potential role of CD38^high/HLA-DR⁺ CD8⁺ T cells as HLH diagnostic biomarker. • The flow cytometry assay, performed at the disease onset before starting treatment, revealed a mean percentage value of CD38 cells of 36.95% among CD8⁺ T cells.

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).

Changing Disease Course of Crimean-Congo Hemorrhagic Fever in Children, Turkey

Crimean-Congo hemorrhagic fever (CCHF), endemic in certain regions of the world, is listed as a priority disease with pandemic potential. Since CCHF was first identified in Turkey, children have been known to experience milder disease than adults. However, during the COVID-19 pandemic, we observed an unusually severe disease course, including hemophagocytic lymphohistiocytosis (HLH). We examined cytokine/chemokine profiles of 9/12 case-patients compared with healthy controls at 3 time intervals. Interferon pathway-related cytokines/chemokines, including interleukin (IL) 18, macrophage inflammatory protein 3α, and IL-33, were elevated, but tumor necrosis factor-α, IL-6, CXCL8 (formerly IL-8), and cytokines acting through C-C chemokine receptor 2 and CCR5 were lower among case-patients than controls. Interferon pathway activation and cytokines/chemokines acting through CCR2 and CCR5 improved health results among children with severe CCHF. Children can experience severe CCHF, including HLH, and HLH secondary to CCHF can be successfully treated with intravenous immunoglobulin and steroid therapy.

Case Report: Parvovirus B19 infection complicated by hemophagocytic lymphohistiocytosis in a heart-lung transplant patient

Immunosuppressed patients can contract parvovirus B19, and some may experience hemophagocytic lymphohistiocytosis (HLH). Herein, we describe the first report of hemophagocytic lymphohistiocytosis in a heart-lung transplant patient with concomitant parvovirus B19 infection. The patient was treated with intravenous immune globulin (IVIG) and the features of HLH were remission. This instance emphasizes the significance of parvovirus B19 monitoring in transplant patients with anemia; if HLH complicates the situation, IVIG may be an adequate remedy. Finally, a summary of the development in diagnosing and managing parvovirus B19 infection complicated by HLH is provided.

Selected severe &#8222;haematological&#8220; syndromes in adult intensive care patients

Haemophagocytic syndrome, diffuse alveolar haemorrhage, catastrophic antiphospholipid syndrome and various types of thrombotic microangiopathies are rare conditions with significant morbidity and mortality. A common feature is late diagnosis, which can affect the success of treatment. The aim of this review article is to summarize the basic diagnostic and therapeutic steps of the present subpopulation of critically ill patients.

Case report: Optimized ruxolitinib-based therapy in an infant with familial hemophagocytic lymphohistiocytosis type 3

Familial hemophagocytic lymphohistiocytosis (FHL) is a rare and fatal autosomal recessive immune disorder characterized by uncontrolled activation of T and NK cells, macrophages, and overproduction of inflammatory cytokines. Early hematopoietic cell transplantation (HCT) is required for long-term survival. Current therapy is based on the HLH-94/2004 protocol, but is insufficient to fully control disease activity. This case report describes an infant with FHL type 3 who, despite initial therapy with dexamethasone and etoposide, showed aberrant cytokine levels, including interleukin-18 (IL-18), chemokine ligand 9 (CXCL9), soluble interleukin-2 receptor (sIL-2R), and soluble tumor necrosis factor receptor type II (sTNF-RII). The Janus kinase inhibitor ruxolitinib was therefore coadministered. The patient was treated with dose-adjusted ruxolitinib guided by cytokine profiles, and was successfully prepared for HCT. The results demonstrate the effectiveness and safety of dose-adjusted ruxolitinib as a bridging therapy for FHL, and the value of monitoring cytokine levels, especially IL-18, CXCL9, sIL-2R, and sTNF-RII, as disease-activity markers for FHL.

Hemophagocytic lymphohistocytosis in trisomy 21: successful treatment with interferon inhibition

BACKGROUND

Hemophagocytic lymphohistiocytosis (HLH) is a life-threatening condition of immune dysregulation primarily driven by the cytokine interferon gamma. It can be either a genetic or acquired disorder associated with infection, malignancy, and rheumatologic disorders. Trisomy 21 can express a wide range of phenotypes which include immune dysregulation and shares inherent pathophysiology with a group of disorders termed interferonopathies. Knowledge of this overlap in seemingly unrelated conditions could provide a basis for future research, and most importantly, alternative therapeutic interventions in acute life threatening clinical scenarios. Herein, we describe two patients with trisomy 21 presenting with HLH that was refractory to conventional treatment. Both patients were successfully managed with novel interventions targeting the interferon pathway.

CASE PRESENTATION

We describe a 17-month-old male and 15-month-old female with trisomy 21 presenting with a myriad of signs and symptoms including fever, rash, cytopenias, and hyperferritinemia, both ultimately diagnosed with HLH. Each had relapsing, refractory HLH over time requiring several admissions to the hospital receiving conventional high dose corticosteroids and interleukin-1 inhibition therapy. Successful steroid-free remission was achieved after targeting interferon inhibition with emapalumab induction followed by long-term maintenance on baricitinib.

CONCLUSION

To our knowledge, these are the first reported cases of relapsed, refractory HLH in patients with trisomy 21 successfully treated with emapalumab and transitioned to a steroid-sparing regimen with oral baricitinib for maintenance therapy. Trisomy 21 autoimmunity and HLH are both thought to be driven by interferon gamma. Targeting therapy toward interferon signaling in both HLH and autoimmunity in trisomy 21 may have potential therapeutic benefits. Further investigation is needed to determine if trisomy 21 may predispose to the development of HLH given this common pathway.

Treatment-related hemophagocytic lymphohistiocytosis due to atezolizumab: a case report and review of the literature

Background

Immune checkpoint inhibitors avoid inhibition of T-cell responses, upregulating antitumor immune response. Moreover, a dysregulation with hyperactive immune response can be caused, some of them underdiagnosed. Hemophagocytic lymphohistiocytosis is a rare and often fatal syndrome of uncontrolled and ineffective hyperinflammatory response that triggers an inflammatory cascade that can lead in many cases to death.

Case presentation

We report the case of a 67-year-old Caucasian man with stage IV lung adenocarcinoma who developed hemophagocytic lymphohistiocytosis after initiation of atezolizumab, an antagonist of programmed death-ligand 1. Even with early diagnosis and proper treatment, death occurs in approximately half of all cases reported.

Conclusion

Key markers are needed to better identify patients at risk of developing severe immune-related adverse events. In addition to key markers, a higher degree of suspicion and early intervention are needed to improve outcomes in acquired hemophagocytic lymphohistiocytosis, especially with the increasingly and expanding use of immune activation.

Hemophagocytic lymphohistiocytosis in HIV-associated lymphoproliferative disorders

Compared to the general population the incidence of lymphoproliferative disorders (LPDs) is significantly elevated among people living with HIV (PLHIV). In high-income countries LPDs have become the most common HIV-associated cause of death among PLHIV. Lymphomas are one of the most frequent triggers of Hemophagocytic Lymphohistiocytosis (HLH), a life-threatening inflammatory syndrome that manifests as a sepsis-like syndrome thus obscuring the underlying condition and delaying its diagnosis and therapy. We performed this retrospective cohort study comprising all adult HIV-infected patients who started treatment for histologically proven LPDs between October 2013 and July 2019, to analyse risk factors, frequency and outcome of HLH among HIV-infected patients with LPDs. Of 75 patients, six (8%) presented with or developed HLH. Three patients had Hodgkin lymphoma and three had HHV-8 associated diseases. There was a significant correlation (p<0.01) between bone marrow involvement and the development of HLH. HLH was associated with lower overall survival (HR: 5.09; 95%CI: 1.53 - 16.91 p=0.008). In conclusion HLH appears to be more frequent in HIV-associated lymphomas than in HIV-negative lymphomas. The probability of developing HLH was particularly high in patients with Hodgkin lymphoma, lymphoma with bone marrow infiltration and HHV-8 associated lymphoma. Mortality was significantly increased in the presence of HLH.

Aberrant inflammatory responses to type I interferon in STAT2 or IRF9 deficiency

BACKGROUND

Inflammatory phenomena such as hyperinflammation or hemophagocytic lymphohistiocytosis are a frequent yet paradoxical accompaniment to virus susceptibility in patients with impairment of type I interferon (IFN-I) signaling caused by deficiency of signal transducer and activator of transcription 2 (STAT2) or IFN regulatory factor 9 (IRF9).

OBJECTIVE

We hypothesized that altered and/or prolonged IFN-I signaling contributes to inflammatory complications in these patients.

METHODS

We explored the signaling kinetics and residual transcriptional responses of IFN-stimulated primary cells from individuals with complete loss of one of STAT1, STAT2, or IRF9 as well as gene-edited induced pluripotent stem cell-derived macrophages.

RESULTS

Deficiency of any IFN-stimulated gene factor 3 component suppressed but did not abrogate IFN-I receptor signaling, which was abnormally prolonged, in keeping with insufficient induction of negative regulators such as ubiquitin-specific peptidase 18 (USP18). In cells lacking either STAT2 or IRF9, this late transcriptional response to IFN-α2b mimicked the effect of IFN-γ.

CONCLUSION

Our data suggest a model wherein the failure of negative feedback of IFN-I signaling in STAT2 and IRF9 deficiency leads to immune dysregulation. Aberrant IFN-α receptor signaling in STAT2- and IRF9-deficient cells switches the transcriptional output to a prolonged, IFN-γ-like response and likely contributes to clinically overt inflammation in these individuals.

Late haemophagocytic lymphohistiocytosis in a patient treated with Axicabtagene ciloleucel

Secondary haemophagocytic lymphohistiocytosis (sHLH) is a life-threatening disorder described in the setting of infections, neoplastic and immune dysregulations. Recently, sHLH has been reported following chimeric antigen receptor T-cell (CAR-T) therapy as a severe manifestation of cytokine release syndrome (CRS) which generally occurs during the early phase after a CAR-T infusion. CAR-T therapy for both relapse/refractory acute lymphoblastic B-cell leukaemia (B-ALL) and non-Hodgkin lymphoma, (diffuse large B-cell lymphoma (DLBCL) and primary mediastinal B-cell lymphoma (PMBCL)), has been approved by FDA and EMA as a third line treatment. CRS is on-target off-tumour side effect of CAR-T therapy which results in an acute state of hyperinflammation due to both tumour lysis and the proliferation of CAR-T cells. Its clinical presentation has a wide spectrum of severity, in the worst case it could rapidly lead to a multiorgan failure and progress to a fatal sHLH. Here, we present a late occurrence of sHLH after CAR-T treatment.

L-DEP regimen is effective as an initial therapy for adult EBV-HLH

We performed a single-center, prospective trial to investigate the efficacy of PEG- asparaginase combined with liposomal doxorubicin, etoposide, and methylprednisolone (L-DEP) as an initial therapy for Epstein-Barr virus driven hemophagocytic lymphohistiocytosis (EBV-HLH). None of the patients received any chemotherapy after the diagnosis of EBV-HLH between September 2019 and September 2021. The efficacy was evaluated 2 weeks and 4 weeks after initiating L-DEP primary therapy. Forty-seven eligible patients with EBV-HLH were enrolled. The overall response rate (ORR) was 80.9% (38/47, 12 in clinical CR, 26 in clinical PR) at 2 weeks after the L-DEP regimen; at 4 weeks, the ORR was 75.6% (34/45, 21 in clinical CR, 13 in clinical PR). EBV-DNA loads in blood and plasma were significantly decreased 2 and 4 weeks after the L-DEP regimen (P < 0.001). Ferritin, soluble CD25 (sCD25), triglycerides (TGs), and ultrasonic spleen longitude, and thickness were all decreased significantly 2 and 4 weeks after the L-DEP regimen (P < 0.001). Thus, the L-DEP regimen is an effective initial therapy for EBV-HLH. However, the L-DEP regimen was poor in terms of long-term prognosis and that allo-HSCT should be received as soon as possible once a complete response is achieved.

TNFAIP3 mutation causing haploinsufficiency of A20 with a hemophagocytic lymphohistiocytosis phenotype: a report of two cases

BACKGROUND

A20 haploinsufficiency (HA20) is a newly introduced autosomal dominant autoinflammatory disorder, also known as Behcet's-like disease. Some of the most common symptoms of the disease are recurrent oral, genital, and/or gastrointestinal (GI) ulcers, episodic fever, musculoskeletal symptoms, cutaneous lesions, and recurrent infections. Hemophagocytic lymphohistiocytosis (HLH) is a life-threatening condition of multi-organ failure due to excessive immune activation. HLH has been reported in a few HA20 patients. Herein, we report two children with the primary presentation of HLH, with a mutation in TNFAIP3, in favor of HA20.

CASE PRESENTATIONS

Our first patient was a 4-month-old boy who presented with fever, irritability, pallor, and hepatosplenomegaly. Pancytopenia, elevated ferritin, and decreased fibrinogen levels were found in laboratory evaluation. He was diagnosed with HLH and was treated with methylprednisolone and cyclosporine. Two years later, whole exome sequencing (WES) indicated a mutation in TNFAIP3 at NM_001270507: exon3: c.C386T, p.T129M, consistent with A20 haploinsufficiency. Etanercept, a TNF inhibitor, was prescribed, but the parents were reluctant to initiate the therapy. The patient passed away with the clinical picture of cerebral hemorrhage. The second patient was a 3-month-old boy who presented with a fever and hepatosplenomegaly. Laboratory evaluation found pancytopenia, hyperferritinemia, hypoalbuminemia, hypertriglyceridemia, and hypofibrinogenemia. With the establishment of the HLH diagnosis, he was treated with etoposide, dexamethasone, and cyclosporine, and recovered. WES results revealed a heterozygous de novo variant of TNFAIP3 (c. T824C in exon 6, 6q23.3) that leads to a proline to leucine amino acid change (p. L275P). He was treated with etanercept and has been symptom-free afterward.

CONCLUSIONS

This report is a hypothesis for developing of the HLH phenotype in the presence of TNFAIP3 mutation. Our results provide a new perspective on the role of TNFAIP3 mutation in HLH phenotypes, but more extensive studies are required to confirm these preliminary results.

The diagnostic importance of multiple cytokines in adult hemophagocytic lymphohistiocytosis

BACKGROUND

Hemophagocytic lymphohistiocytosis (HLH) is a category of immunological illnesses that cause out-of-control T cells and macrophages to release life-threatening cytokines. The HLH-2004 diagnostic criteria are the gold standard for HLH diagnosis, but there is a need to investigate the usefulness of various cytokines for HLH diagnosis.

METHODS

Patients admitted to Beijing Friendship Hospital of Capital Medical University from January 2016 to December 2020 were included in this retrospective study, with 166 patients with confirmed HLH and 142 febrile patients requiring differential diagnosis completing the sum. Multiplex cytokine assays using multifactor liquid phase microarray technology-based multifactor liquid phase microarray technology were used to detect 33 cytokines. Twenty-eight cytokines detected using the Luminex analytical platform technology were ultimately included in the analysis.

RESULTS

Interleukin-1 receptor antagonist (IL-1 RA), IL-18, interferon-γ (IFN-γ), and interferon-induced protein 10 (IP-10) regulated upon activation normal T cell expressed and secreted (RANTES), eotaxin, growth-related oncogene α (GRO-α), and macrophage inflammatory protein-1 α (MIP-1α) were higher in the HLH group than in the non-HLH group, and the differences were statistically significant. Among them, the area under the curve (AUC) for IL-18 for HLH diagnosis was reported for the first time as 82.69%, with a sensitivity of 76.32% and a specificity of 79.61%; the AUC of IL-1 RA was 72.34%, with a sensitivity of 62.71% and a specificity of 75.97%; and the AUC of IP-10 was 71.73%, with a sensitivity of 60.14% and a specificity of 75.15%. Moreover, the AUC of the combined diagnostic tests for IL-1 RA, IL-18, IFN-γ, IP-10, and RANTES was 99.6%, with a sensitivity of 95.8% and a specificity of 98.6%.

CONCLUSION

Our study concluded that multiple cytokines are valid biological markers for the diagnosis of HLH. The findings of this study remain to be validated in an external dataset.

Serum soluble interleukin-2 receptor (sIL-2R) is an accurate biomarker for dengue-associated hemophagocytic lymphohistiocytosis syndrome diagnosed by Hscore

Objective

Hemophagocytic lymphohistiocytosis is a potentially fatal complication of severe dengue fever. Here we evaluated the serum soluble IL-2R levels as potential biomarker for identifying HLH in patients with dengue fever.

Methods

In this cross-sectional study conducted in a tertiary care center of a teaching hospital, subjects with dengue and fever of more than 5 days, leukopenia/thrombocytopenia and/or hepatosplenomegaly were studied. Data were collected to compare sIL-2R values and serum ferritin with Hscore and Histiocyte Society 2004 criteria. Relevant statistical methods were used.

Results

80 subjects with severe dengue fever were analyzed with relevant investigations. Mean H score was 219.2 ± 17.6 in 18 dengue patients with HLH v/s 166.2 ± 11.2 in 62 patients without HLH (p =  < 0.001). Serum ferritin (11,230.5 v/s 7853.5, p = 0.013) and sIL-2R (32,917.5 v/s 6210, p = < 0.001) were significantly higher in those patients with HLH. sIL-2R correlated very well with HScore (r = 0.98, p < 0.001) compared to ferritin (r = 0.51, p < 0.001) with an AUROC of 1.00 compared to 0.694 (95% CI 0.557–0.831) of serum ferritin for diagnosing HLH. A cut-off value of 10,345 pg/ml for sIL-2R had a sensitivity and specificity of 100% for HLH, whereas, a ferritin value of 8613 ng/ml had only 67% sensitivity and 55% specificity.

Conclusion

sIL-2R could be a single most useful biomarker to differentiate dengue fever patients who are likely to progress to HLH, from those that are not. Full workup for HLH could be limited only to those patients with elevated sIL-2R, especially in resource limited settings.

Supplementary Information

The online version contains supplementary material available at 10.1007/s15010-022-01906-8.

Anakinra for the treatment of adult secondary HLH: a retrospective experience

Anti-cytokine therapies have been gaining attention as a means of improving outcomes in adult secondary HLH (asHLH), which currently has poor outcomes when treated with standard etoposide-based therapies. Anakinra is an interleukin-1 antagonist that is increasingly being used in the management of asHLH. Here is described a multi-hospital series of 16 adult patients with secondary HLH treated with anakinra. Provoking factors of secondary HLH included hematologic malignancy (n = 7, 44%), bacterial infection (n = 7, 44%), viral infection (n = 5, 31%), rheumatologic disorder (n = 4, 25%), and unknown (n = 1, 6%). Five patients remained alive at time of last follow-up (OS = 31%). Median OS was 1.7 months from initiation of anakinra (range 0.2–59). OS among patients with rheumatologic causes of secondary HLH was 75%, whereas only 17% of patients with other provoking factors survived (p = 0.0293). Anakinra was well tolerated, with only 1 patient experiencing associated toxicity (grade 3 liver injury). Anakinra may be useful in the management of asHLH provoked by rheumatologic conditions, although its benefit in asHLH provoked by other factors may be limited.