Hemophagocytic lymphohistiocytosis (HLH): A heterogeneous spectrum of cytokine-driven immune disorders

Myeloma-associated hemophagocytic lymphohistiocytosis - A comprehensive case study and a novel chemotherapy-free approach with anakinra

Hemophagocytic lymphohistiocytosis (HLH) is an immune response syndrome characterized by excessive inflammation and tissue destruction. A limited number of cases involving HLH patients with concomitant multiple myeloma (MM), leading to significant mortality, have been documented, underscoring the importance of timely diagnosis. We present the case of a 78-year-old previously healthy male admitted to our hospital with a newly diagnosed MM. Subsequently, he was diagnosed with HLH and received treatment with anakinra, intravenous immunoglobulin, and dexamethasone. This case report highlights the unique aspect of being the first documented instance of myeloma-associated HLH treated with anakinra.

A Novel Engineering Cell Therapy Platform Mimicking the Immune Thrombocytopenia-Derived Platelets to Inhibit Cytokine Storm in Hemophagocytic Lymphohistiocytosis

Hemophagocytic lymphohistiocytosis (HLH) is a common and highly fatal hyperinflammatory syndrome characterized by the aberrant activation of macrophages. To date, there is a lack of targeted therapies for HLH. It is validated that macrophages in HLH efficiently phagocytose anti-CD41-platelets (anti-CD41-PLTs) from immune thrombocytopenia (ITP) patients in previous research. Hence, the pathological mechanisms of ITP are mimicked and anti-CD41-PLTs are utilized to load the macrophage-toxic drug VP16 to construct macrophage-targetable engineered platelets anti-CD41-PLT-VP16, which is a novel targeted therapy against HLH. Both in vitro and in vivo studies demonstrate that anti-CD41-PLT-VP16 has excellent targeting and pro-macrophage apoptotic effects. In HLH model mice, anti-CD41-PLT-VP16 prevents hemophagocytosis and inhibits the cytokine storm. Mechanistic studies reveal that anti-CD41-PLT-VP16 increases the cytotoxicity of VP16, facilitating precise intervention in macrophages. Furthermore, it operates as a strategic "besieger" in diminishing hyperinflammation syndrome, which can indirectly prevent the abnormal activation of T cells and NK cells and reduce the Ab-dependent cell-mediated cytotoxicity effect. The first platelet-based clinical trial is ongoing. The results show that after treatment with anti-CD41-PLT-VP16, HLH patients have a threefold increase in the overall response rate compared to patients receiving conventional chemotherapy. In conclusion, anti-CD41-PLT-VP16 provides a general insight into hyperinflammation syndrome and offers a novel clinical therapeutic strategy for HLH.

Hemophagocytic lymphohistiocytosis associated with brucellosis

Hemophagocytic lymphohistiocytosis (HLH) is a life-threatening immune disorder categorized as familial HLH or secondary HLH. Our case report describes a 63-year-old woman with epilepsy whose clinical signs were unremitting fever and altered consciousness. Primary abnormalities consisted of fever, splenomegaly, cytopenia, hypertriglyceridemia, hyperferritinemia and hemophagocytosis in the bone marrow. Results of blood next generation sequencing and blood culture confirmed Brucella infection. This report illustrates a sHLH case caused by Brucella melitensis infection. Here, we review the classification, clinical features, diagnostic methods, treatment regimens, differential diagnosis, and prognosis of HLH and brucellosis.

Successful Second CBT for Graft Failure After First CBT for Adult-Onset Familial Hemophagocytic Lymphohistiocytosis Type 3: A Case Report

Familial hemophagocytic lymphohistiocytosis (FHL) is a rare inherited autosomal recessive immune deficiency that usually manifests during infancy or early childhood, rarely occurring in adults. Hematopoietic stem cell transplantation (HSCT) is the only curative treatment for FHL. However, optimal conditioning regimens for adult-onset FHL have not yet been established. Herein, we report a case of adult-onset FHL. A 37-year-old man presented with fever, liver dysfunction, and pancytopenia, which improved temporarily with corticosteroid therapy. However, he later developed encephalitis and myelitis. Genetic analysis revealed rare variants of UNC13D (c.2367+1 g>a and c.2588 g>a), which were compound heterozygous pathogenic mutations. FHL type 3 was diagnosed, and treatment based on the hemophagocytic lymphohistiocytosis (HLH) 1994 protocol was initiated. The patient underwent cord blood transplantation (CBT) with myeloablative conditioning using fludarabine, melphalan, and total-body irradiation (TBI), which resulted in graft rejection. The patient was successfully rescued by a second CBT following reduced-intensity conditioning with fludarabine, cyclophosphamide, and TBI. Although graft failure is an important complication especially in CBT, it could be managed by appropriate treatment, and that cord blood would be a promising alternative source with the advantages of rapidity and avoidance of related donors with a high risk of harboring the same genetic mutation.

Heterogeneity of macrophage activation syndrome and treatment progression

Macrophage activation syndrome (MAS) is a rare complication of autoimmune inflammatory rheumatic diseases (AIIRD) characterized by a progressive and life-threatening condition with features including cytokine storm and hemophagocytosis. Predisposing factors are typically associated with microbial infections, genetic factors (distinct from typical genetically related hemophagocytic lymphohistiocytosis (HLH)), and inappropriate immune system overactivation. Clinical features include unremitting fever, generalized rash, hepatosplenomegaly, lymphadenopathy, anemia, worsening liver function, and neurological involvement. MAS can occur in various AIIRDs, including but not limited to systemic juvenile idiopathic arthritis (sJIA), adult-onset Still's disease (AOSD), systemic lupus erythematosus (SLE), Kawasaki disease (KD), juvenile dermatomyositis (JDM), rheumatoid arthritis (RA), and Sjögren's syndrome (SS), etc. Although progress has been made in understanding the pathogenesis and treatment of MAS, it is important to recognize the differences between different diseases and the various treatment options available. This article summarizes the cell types and cytokines involved in MAS-related diseases, the heterogeneity, and treatment options, while also comparing it to genetically related HLH.

Does your unwell patient have haemophagocytic lymphohistiocytosis?

Haemophagocytic lymphohistiocytosis is a severe systemic hyperinflammatory syndrome characterised by dysregulation of immune cells and excessive production of cytokines, also known as a cytokine storm. It has distinctive clinical features with fever, hyperferritinaemia and falling blood counts. In adults, this usually occurs secondary to an underlying driver or trigger including infection, malignancy or rheumatic diseases. Prompt treatment with immunomodulatory therapy, including corticosteroids and the recombinant IL-1 receptor antagonist anakinra, is recommended to switch off the cytokine storm. Etoposide-based regimens are sometimes needed, and newer therapies such as emapalumab and JAK inhibitors are increasingly being used. The incidence of haemophagocytic lymphohistiocytosis has increased significantly over the last 20 years which may partly reflect increased awareness of the condition. Although relatively rare, haemophagocytic lymphohistiocytosis can be encountered by a broad range of hospital physicians, so knowing how to diagnose and treat this condition is essential. This article reviews the pathogenesis, clinical features, causes, diagnosis and treatment of haemophagocytic lymphohistiocytosis to improve physician recognition and management of this condition to improve future patient outcomes.

Immunopathology of and potential therapeutics for secondary hemophagocytic lymphohistiocytosis/macrophage activation syndrome: a translational perspective

Secondary hemophagocytic lymphohistiocytosis/macrophage activation syndrome (sHLH/MAS) is a life-threatening immune disorder triggered by rheumatic disease, infections, malignancies, or medications. Characterized by the presence of hemophagocytic macrophages and a fulminant cytokine storm, sHLH/MAS leads to hyperferritinemia and multiorgan failure and rapidly progresses to death. The high mortality rate and the lack of specific treatments necessitate the development of a new drug. However, the complex and largely unknown immunopathologic mechanisms of sHLH/MAS, which involve dysfunction of various immune cells, diverse etiologies, and different clinical contexts make this effort challenging. This review introduces the terminology, diagnosis, and clinical features of sHLH/MAS. From a translational perspective, this review focuses on the immunopathological mechanisms linked to various etiologies, emphasizing potential drug targets, including key molecules and signaling pathways. We also discuss immunomodulatory biologics, existing drugs under clinical evaluation, and novel therapies in clinical trials. This systematic review aims to provide insights and highlight opportunities for the development of novel sHLH/MAS therapeutics.

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 Features of Cytokine Storm Syndrome

Cytokine storm syndrome (CSS) is a severe life-threatening condition characterized by a clinical phenotype of overwhelming systemic inflammation, hyperferritinemia, hemodynamic instability, and multiple organ failure (MOF), and, if untreated, it can potentially lead to death. The hallmark of CSS is an uncontrolled and dysfunctional immune response involving the continual activation and expansion of lymphocytes and macrophages, which secrete large amounts of cytokines, causing a cytokine storm. Many clinical features of CSS can be explained by the effects of pro-inflammatory cytokines, such as interferon (IFN)-γ, tumor necrosis factor (TNF), interleukin (IL)-1, IL-6, and IL-18 [1-7]. These cytokines are elevated in most patients with CSS as well as in animal models of CSS [8, 9]. A constellation of symptoms, signs, and laboratory abnormalities occurs that depends on the severity of the syndrome, the underlying predisposing conditions, and the triggering agent.

Murine Models of Familial Cytokine Storm Syndromes

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

The Role of the IL-33/ST2 Axis in CpG-Induced Macrophage Activation Syndrome

Background

Macrophage activation syndrome (MAS) is a fatal inflammatory condition, which is often associated with the elevation of multiple proinflammatory cytokines and multiple organ dysfunction. Previous studies have shown that ST2 contributes to T cell overactivation and plays a detrimental role in mouse models of primary hemophagocytic lymphohistiocytosis. The purpose of this study was to investigate the role of the IL-33/ST2 axis in a mouse model of MAS induced by repeated injections of cytosine-phosphate-guanine (CpG).

Methods

Serum cytokines were determined using the cytometric bead array by flow cytometry. IL-33 and ST2 were detected by immunohistochemistry and real-time quantitative PCR in the liver and spleen of mice. CD3 and F4/80 in the liver were detected by immunohistochemistry. Inflammatory macrophages and effector memory T lymphocytes were detected by flow cytometry.

Result

The CpG-induced MAS model was successfully induced after repeated CpG injections, presenting with hypercytokinemia and hepatosplenomegaly. The numbers of IL-33 positive cells in the liver and spleen decreased significantly, while the expression of ST2 in the liver tended to increase in the mice with MAS. IL-33 and St2 knockout mice showed similar levels of hepatosplenomegaly, peripheral blood count, and cytokine storm when compared with wild-type (WT) mice after induction of MAS. There were also no significant differences in liver pathology (including inflammatory cell infiltration of CD3 and F4/80) and levels of splenic inflammatory macrophages and effector memory T cells between the WT and knockout mice.

Conclusion

These results suggested that IL-33 decreased in the liver and spleen tissues of MAS mice. Further results suggest that IL-33 and St2 knockout mice have no treatment potential in CpG-induced MAS. Thus, the IL-33/ST2 axis has little effect on the prognosis of CpG-induced MAS.

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.

The Multifaceted Immunology of Cytokine Storm Syndrome

Cytokine storm syndromes (CSSs) are potentially fatal hyperinflammatory states that share the underpinnings of persistent immune cell activation and uninhibited cytokine production. CSSs can be genetically determined by inborn errors of immunity (i.e., familial hemophagocytic lymphohistiocytosis) or develop as a complication of infections, chronic inflammatory diseases (e.g., Still disease), or malignancies (e.g., T cell lymphoma). Therapeutic interventions that activate the immune system such as chimeric Ag receptor T cell therapy and immune checkpoint inhibition can also trigger CSSs in the setting of cancer treatment. In this review, the biology of different types of CSSs is explored, and the current knowledge on the involvement of immune pathways and the contribution of host genetics is discussed. The use of animal models to study CSSs is reviewed, and their relevance for human diseases is discussed. Lastly, treatment approaches for CSSs are discussed with a focus on interventions that target immune cells and cytokines.

Insights into the cellular pathophysiology of familial hemophagocytic lymphohistiocytosis

Familial hemophagocytic lymphohistiocytosis (fHLH) encompasses a group of rare inherited immune dysregulation disorders characterized by loss-of-function mutations in one of several genes involved in the assembly, exocytosis, and function of cytotoxic granules within CD8+ T cells and natural killer (NK) cells. The resulting defect in cytotoxicity allows these cells to be appropriately stimulated in response to an antigenic trigger, and also impairs their ability to effectively mediate and terminate the immune response. Consequently, there is sustained lymphocyte activation, resulting in the secretion of excessive amounts of pro-inflammatory cytokines that further activate other cells of the innate and adaptive immune systems. Together, these activated cells and pro-inflammatory cytokines mediate tissue damage that leads to multi-organ failure in the absence of treatment aimed at controlling hyperinflammation. In this article, we review these mechanisms of hyperinflammation in fHLH at the cellular level, focusing primarily on studies performed in murine models of fHLH that have provided insight into how defects in the lymphocyte cytotoxicity pathway mediate rampant and sustained immune dysregulation.

Cytokine nanosponges suppressing overactive macrophages and dampening systematic cytokine storm for the treatment of hemophagocytic lymphohistiocytosis

Hemophagocytic lymphohistiocytosis (HLH) is a highly fatal condition with the positive feedback loop between continued immune cell activation and cytokine storm as the core mechanism to mediate multiple organ dysfunction. Inspired by macrophage membranes harbor the receptors with special high affinity for proinflammation cytokines, lipopolysaccharide (LPS)-stimulated macrophage membrane-coated nanoparticles (LMNP) were developed to show strong sponge ability to both IFN-γ and IL-6 and suppressed overactivation of macrophages by inhibiting JAK/STAT signaling pathway both in vitro and in vivo. Besides, LMNP also efficiently alleviated HLH-related symptoms including cytopenia, hepatosplenomegaly and hepatorenal dysfunction and save the life of mouse models. Furthermore, its sponge effect also worked well for five human HLH samples in vitro. Altogether, it's firstly demonstrated that biocompatible LMNP could dampen HLH with high potential for clinical transformation, which also provided alternative insights for the treatment of other cytokine storm-mediated pathologic conditions such as COVID-19 infection and cytokine releasing syndrome during CAR-T therapy.

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LMNP functioned better as a multiple-cytokine sponging tool when compared with conventional macrophage coated nanoparticles.

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LMNP sponged inflammation cytokines and suppressed macrophage overactivation by inhibiting JAK/STAT signaling pathway.

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LMNP calmed down systematic cytokine storm and dampened HLH in HLH mice models.

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LMNP also worked well in sponging cytokines in human HLH samples which indicated high potential of clinical transformation.

Epstein-Barr virus-associated haemophagocytic lymphohistiocytosis complicated by neurological involvement in a patient with dermatomyositis: A case report and literature review

Haemophagocytic lymphohistiocytosis (HLH) is an extremely high mortality condition that can occur at any age and lacks specific diagnostic characteristics. Despite its rarity, HLH is increasingly alarming because of the high mortality rate. It is a systemic hyperinflammatory immune response syndrome associated with abnormal activation of T cells and macrophages, which may be caused by genetic mutations or acquired factors, such as infection, autoimmune condition, and malignancy. Here, we present a fatal case of Epstein-Barr virus-associated HLH complicated by neurological involvement in a patient with dermatomyositis. We describe and discuss the pathological features, classification, and effective treatment options of HLH and discuss separately the special characteristics of Epstein-Barr virus-associated HLH and dermatomyositis-associated HLH.

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 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.

Secondary hemophagocytic lymphohistiocytosis triggered by peripheral T-cell lymphoma: An unusual case report

Hemophagocytic lymphohistiocytosis (HLH) is a severe syndrome of pathological immune activation caused by activated macrophages and cytotoxic T cells. We report a 65-year-old male Chinese patient with typical HLH features caused by peripheral T-cell lymphoma and then received chemotherapy. However, though the patient's symptoms and signs improved much, his liver function, especially bilirubin, worsened which could be caused by overwhelming cytokines production. Therefore, plasmapheresis was conducted two times and then his liver function significantly recovered. The patient got temporary remission and good quality of life for nearly 2 months but died because of disease progression. In conclusion, as HLH is associated with multiorgan failure, high rates of morbidity and mortality, there are three points to be mentioned. First, it is critical that HLH should be screened as early as possible and initiate effective therapies. Second, plasmapheresis could be a useful method to eliminate excess cytokines production and improve liver function. Third, organs support and nutrient supply are also necessary and important.

Limited efficacy of tocilizumab in adult patients with secondary hemophagocytic lymphohistiocytosis: a retrospective cohort study

Background

Interleukin (IL)-6 is one of the key cytokines in the pathogenesis of secondary hemophagocytic lymphohistiocytosis (sHLH); however, the efficacy and safety of tocilizumab (TCZ), a monoclonal IL-6 receptor antibody, in patients with sHLH is uncertain.

Methods/Results

This study included 64 adult patients who were diagnosed with sHLH based on the HLH-2004 criteria. Patients were classified into two groups based on treatment regimen at baseline: tocilizumab (TCZ group, n = 8) versus other treatments (control group), including HLH-2004 protocol (n = 35), chemotherapy (n = 7), glucocorticoid alone (n = 8), and with other immunosuppressants (n = 6). Primary outcome was overall 8-week survival. Baseline characteristics between the two groups were comparable. At day 56, one patient (12.5%) in the TCZ group and twenty-eight patients (51.9%) in the control group survived. Univariable and multivariable Cox proportional hazard analysis showed that TCZ significantly increased the risk of death (adjusted hazard ratio 5.55; 95% CI 2.13–14.49). The complete or partial response rate at day 14 was 44.6% in the control group, and nil in the TCZ group. In contrast, infectious complications occurred more frequently in the TCZ group than in the control group (14.3% vs. 50.0%).

Conclusion

Our results suggest that tocilizumab has limited efficacy in treating adult patients with sHLH and could increase the risk of infectious complications compared to the conventional treatments.

Supplementary Information

The online version contains supplementary material available at 10.1186/s13023-022-02516-1.

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.

Excessive neutrophil recruitment promotes typical T-helper 17 responses in Coronavirus disease 2019 patients

Coronavirus disease 2019 (COVID-19) is caused by a recently identified virus, severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) and the disease is a pandemic. Although the hallmarks of severe COVID-19 have been established, the underlying mechanisms that promote severe pathology have not been thoroughly studied. A better understanding of the immune response in severe COVID-19 patients may help guide the development of therapeutic strategies and predict immuno-pathogenicity. This study was set to determine the lymphocyte and cytokine profiles associated with COVID-19 severity. A total of 43 hospitalised COVID-19 patients were recruited for the study and whole blood samples were drawn from each patient. Complete blood counts, lymphocyte subset profiles and C-reactive protein statuses of patients were determined. Cytometric bead array was performed to analyse the cytokine profiles of each patient. The demographic characteristics showed that the median age of the patients was 48.72 years, with an interquartile range from 40 to 60 years, and 69.77% of the patients were male. COVID-19 patients exhibited significantly low CD4⁺ lymphocyte expansion and leucocytosis augmented by elevated neutrophil and immature granulocytes. Stratification analysis revealed that reduced monocytes and elevated basophils and immature granulocytes are implicated in severe pathology. Additionally, cytokine results were noted to have significant incidences of interleukin 17A (IL-17A) expression associated with severe disease. Results from this study suggest that a systemic neutrophilic environment may preferentially skew CD4⁺ lymphocytes towards T-helper 17 and IL-17A promotion, thus, aggravating inflammation. Consequently, results from this study suggest broad activity immunomodulation and targeting neutrophils and blocking IL-17 production as therapeutic strategies against severe COVID-19.

Case report: Cytokine hemoadsorption in a case of hemophagocytic lymphohistiocytosis secondary to extranodal NK/T-cell lymphoma

We discuss a single case of Hemophagocytic lymphohistiocytosis (HLH) due to NK-type non-Hodgkin lymphoma and Epstein-Barr virus reactivation with multiorgan dysfunction and distributive shock in which we performed cytokine hemoadsorption with Cytosorb ^®. A full microbiological panel was carried out, including screening for imported disease, standard serologies and cultures for bacterial and fungal infection. A liver biopsy and bone marrow aspirate were performed, confirming the diagnosis. The patients fulfilled the HLH-2004 diagnostic criteria, and according to the 2018 Consensus Statements by the HLH Steering Committee of the Histiocyte Society, dexamethasone and etoposide were started. There was an associated hypercytokinemia and, due to refractory distributive shock, rescue therapy with cytokine hemoadsorption was performed during 24 h (within day 2 and 3 from ICU admission). After starting this procedure, rapid hemodynamic control was achieved with a significant reduction in vasopressor support requirements. This case report highlights that cytokine hemoadsorption can be an effective since rapid decrease in IL-10 levels and a significant hemodynamic improvement was achieved.

A fatal SARS-coronavirus-2 induced bone marrow aplasia complicated with invasive fungal infection and severe neutropenic enterocolitis

Background

Immunization against the coronavirus disease 2019 (COVID-19) began in January 2021 in Iran; nonetheless, due to a lack of vaccination among children under 12, this age group is still at risk of SARS-CoV-2 infection and its complications.

Case presentation

SARS-CoV-2 infection was diagnosed in a 6-year-old girl who had previously been healthy but had developed a fever and pancytopenia. The bone marrow aspiration/biopsy demonstrated just hypocellular marrow without signs of leukemia. She was worked up for primary and secondary causes of pancytopenia. Except for a repeated reactive HIV antibody/Ag P24 assay, all test results were inconclusive. After a thorough diagnostic investigation, the cross-reactivity of the HIV antibody/Ag P24 test with SARS-CoV-2 antibodies was confirmed. The patient did not develop any COVID-19-related signs and symptoms, but she did get a severe invasive fungal infection and neutropenic enterocolitis. She died as a result of disseminated intravascular coagulopathy.

Conclusion

It is critical to recognize children infected with SARS-CoV-2 who exhibit atypical clinical manifestations of COVID-19, such as persistent pancytopenia. SARS-CoV-2 infection can cause severe and deadly consequences in children; thus, pediatricians should be aware of COVID-19’s unusual signs and symptoms mimicking other conditions such as aplastic anemia.

nCD64 index as a novel inflammatory indicator for the early prediction of prognosis in infectious and non-infectious inflammatory diseases: An observational study of febrile patients

Background

Generally, febrile patients admitted to the Department of Infectious Diseases, Fudan University Affiliated Huashan Hospital, China may eventually be diagnosed as infectious (ID) or non-infectious inflammatory diseases (NIID). Furthermore, mortality from sepsis remains incredibly high. Thus, early diagnosis and prognosis evaluation of sepsis is necessary. Here, we investigated neutrophil (n)CD64 index profile in a cohort of febrile patients and explored its diagnostic and prognostic value in ID and NIID.

Methods

This observational cohort study enrolled 348 febrile patients from the Emergency Department and Department of Infectious Diseases. nCD64 index were detected using flow cytometry, and dynamically measured at different timepoints during follow-up. Procalcitonin (PCT), C-reactive protein (CRP), and ferritin levels were measured routinely. Finally, the diagnostic and prognostic value of nCD64 index were evaluated by receiver operating characteristic (ROC) analysis and Kaplan-Meier curve analysis.

Results

Of included 348 febrile patients, 238, 81, and 29 were categorized into ID, NIID, and lymphoma groups, respectively. In ID patients, both SOFA score and infection site had impact on nCD64 index expression. In NIID patients, adult-onset Still’s disease patients had the highest nCD64 index value, however, nCD64 index couldn’t distinguish between ID and NIID. Regardless of the site of infection, nCD64 index was significantly higher in bacterial and viral infections than in fungal infections, but it could not discriminate between bacterial and viral infections. In bloodstream infections, gram-negative (G-) bacterial infections showed an obvious increase in nCD64 index compared to that of gram-positive (G+) bacterial infections. nCD64 index has the potential to be a biomarker for distinguishing between DNA and RNA virus infections. The routine measurement of nCD64 index can facilitate septic shock diagnosis and predict 28-day hospital mortality in patients with sepsis. Serial monitoring of nCD64 index in patients with sepsis is helpful for evaluating prognosis and treatment efficacy. Notably, nCD64 index is more sensitive to predict disease progression and monitor glucocorticoid treatment in patients with NIID.

Conclusions

nCD64 index can be used to predict 28-day hospital mortality in patients with sepsis and to evaluate the prognosis. Serial determinations of nCD64 index can be used to predict and monitor disease progression in patients with NIID.

Pediatric inborn errors of immunity causing hemophagocytic lymphohistiocytosis: Case report and review of the literature

Inborn errors of immunity are a group of genetic disorders caused by mutations that affect the development and/or function of several compartments of the immune system, predisposing patients to infections, autoimmunity, allergy and malignancies. In this regard, mutations that affect proteins involved in trafficking, priming, docking, or membrane fusion will impair the exocytosis of lytic granules of effector NK and cytotoxic T lymphocytes. This may predispose patients to hemophagocytic lymphohistiocytosis, a life-threatening immune disorder characterized by systemic lymphocyte and macrophage activation, and increased levels of cytokines, which lead to an uncontrolled hyperinflammation state and progressive multiorgan damage. In this review, we will describe a clinical case and recent advances in inborn errors of immunity predisposing to hemophagocytic lymphohistiocytosis. Summary sentence: Review of recent advances in inborn errors of immunity predisposing to hemophagocytic lymphohistiocytosis.

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.

Comprehensive Cytokine Profiling of Patients with COVID-19 Receiving Tocilizumab Therapy

Coronavirus disease 2019 (COVID-19) is characterized by immune activation in response to viral spread, in severe cases leading to the development of cytokine storm syndrome (CSS) and increased mortality. Despite its importance in prognosis, the pathophysiological mechanisms of CSS in COVID-19 remain to be defined. Towards this goal, we analyzed cytokine profiles and their interrelation in regard to anti-cytokine treatment with tocilizumab in 98 hospitalized patients with COVID-19. We performed a multiplex measurement of 41 circulating cytokines in the plasma of patients on admission and 3-5 days after, during the follow-up. Then we analyzed the patient groups separated in two ways: according to the clusterization of their blood cytokines and based on the administration of tocilizumab therapy. Patients with and without CSS formed distinct clusters according to their cytokine concentration changes. However, the tocilizumab therapy, administered based on the standard clinical and laboratory criteria, did not fully correspond to those clusters of CSS. Furthermore, among all cytokines, IL-6, IL-1RA, IL-10, and G-CSF demonstrated the most prominent differences between patients with and without clinical endpoints, while only IL-1RA was prognostically significant in both groups of patients with and without tocilizumab therapy, decreasing in the former and increasing in the latter during the follow-up period. Thus, CSS in COVID-19, characterized by a correlated release of multiple cytokines, does not fully correspond to the standard parameters of disease severity. Analysis of the cytokine signature, including the IL-1RA level in addition to standard clinical and laboratory parameters may be useful to define the onset of a cytokine storm in COVID-19 as well as the indications for anti-cytokine therapy.

Familial hemophagocytic lymphohistiocytosis hepatitis is mediated by IFN-γ in a predominantly hepatic-intrinsic manner

Interferon gamma (IFN-γ) is the main cytokine driving organ dysfunction in Familial Hemophagocytic Lymphohistiocytosis (FHL). Blockade of IFN-γ pathway ameliorates FHL hepatitis, both in animal models and in humans with FHL. Hepatocytes are known to express IFN-γ receptor (IFN-γ-R). However, whether IFN-γ induced hepatitis in FHL is a lymphocyte or liver intrinsic response to the cytokine has yet to be elucidated. Using a IFNgR-/- bone marrow chimeric model, this study showed that non-hematopoietic IFN-γ response is critical for development of FHL hepatitis in LCMV-infected Prf1-/- mice. Lack of hepatic IFN-γ responsiveness results in reduced hepatitis as measured by hepatomegaly, alanine aminotransferase (ALT) levels and abrogated histologic endothelial inflammation. In addition, IFN-γ non-hematopoietic response was critical in activation of lymphocytes by soluble interleukin 2 receptor (sIL-2r) and recruitment of CD8+ effector T lymphocytes (CD8+ CD44hi CD62Llo) (Teff) and inflammatory monocytes. Lastly, non-hematopoietic IFN-γ response results in increased hepatic transcription of type 1 immune response and oxidative stress response pathways, while decreasing transcription of genes involved in extracellular matrix (ECM) production. In summary, these findings demonstrate that there is a hepatic transcriptional response to IFN-γ, likely critical in the pathogenesis of FHL hepatitis and hepatic specific responses could be a therapeutic target in this disorder.

Hemophagocytic Syndrome-Like Tuberculosis-Immune Reconstitution Inflammatory Syndrome After the Initiation of Hepatic Tuberculosis Treatment

A 25-year-old Nepalese woman was referred to our hospital because of fever and intermittent abdominal pain with inguinal lymphadenopathy, which had lasted for several months. A liver biopsy of the positron emission tomography-positive lesion led to a diagnosis of hepatic tuberculosis. After the initiation of antituberculosis treatment, her symptoms resolved. However, 11 days after treatment initiation, chest and back pain, high-grade fever, and vomiting appeared and gradually worsened. She developed anemia and her serum ferritin level was elevated. Hemophagocytic syndrome due to the initial deterioration of tuberculosis was suspected and steroid therapy was initiated with the continuation of the antituberculosis drugs. Thereafter, the patient’s condition improved remarkably.

Natural Killer Cells in Multiple Sclerosis: Entering the Stage

Studies investigating the immunopathology of multiple sclerosis (MS) have largely focused on adaptive T and B lymphocytes. However, in recent years there has been an increased interest in the contribution of innate immune cells, amongst which the natural killer (NK) cells. Apart from their canonical role of controlling viral infections, cell stress and malignancies, NK cells are increasingly being recognized for their modulating effect on the adaptive immune system, both in health and autoimmune disease. From different lines of research there is now evidence that NK cells contribute to MS immunopathology. In this review, we provide an overview of studies that have investigated the role of NK cells in the pathogenesis of MS by use of the experimental autoimmune encephalomyelitis (EAE) animal model, MS genetics or through ex vivo and in vitro work into the immunology of MS patients. With the advent of modern hypothesis-free technologies such as single-cell transcriptomics, we are exposing an unexpected NK cell heterogeneity, increasingly blurring the boundaries between adaptive and innate immunity. We conclude that unravelling this heterogeneity, as well as the mechanistic link between innate and adaptive immune cell functions will lay the foundation for the use of NK cells as prognostic tools and therapeutic targets in MS and a myriad of other currently uncurable autoimmune disorders.

Mechanistic Insights in Hemophagocytic Lymphohistiocytosis: Subsequent Acute Hepatic Failure in a Multiple Myeloma Patient following Therapy with Ixazomib-Lenalidomide-Dexamethasone

Hemophagocytic lymphohistiocytosis (HLH) is a rare, elusive, and life-threatening condition that is characterized by the pathologic and uncontrolled secondary activation of the cytotoxic T-cells, natural killer cells (NK-cells), and macrophages of the innate immune system. This condition can develop in sporadic or familial contexts associated with hematological malignancies, as a paraneoplastic syndrome, or linked to an infection related to immune system deficiency. This leads to the systemic inflammation responsible for the overall clinical manifestations. Diagnosis should be thorough, and treatment should be initiated as soon as possible. In the current manuscript, we focus on classifying the HLH spectrum, describing the pathophysiology and the tools needed to search for and correctly identify HLH, and the current therapeutic opportunities. We also present the first case of a multiple myeloma patient that developed HLH following therapy with the ixazomib-lenalidomide-dexamethasone protocol.

Successful treatment of hemophagocytic syndrome in a patient with T cell lymphoma, EBV infection, and bone marrow necrosis: A case report

RATIONALE

Hemophagocytic syndrome (HPS) is associated with a high mortality rate, and Epstein-Barr virus infection and hematological malignancies, especially T/natural killer cell lymphomas, are the most common causes; however, due to the complexity of clinical manifestations, the diagnosis is usually delayed. There are few reports of lymphoma-associated HPS (LAPS) in combination with bone marrow necrosis, and there is still no standard treatment for LAPS.

PATIENT CONCERNS

A 64-year-old man developed a fever, mild jaundice, fatigue, and bone pain. Positron emission tomography and bone marrow biopsy with immunohistochemistry were performed.

DIAGNOSIS

Imaging analysis and bone marrow examinations were compatible with HPS, T-cell lymphoma, and bone marrow necrosis.

INTERVENTIONS

The patient received combination therapy of rituximab and Cyclophosphamide, epirubicin, vincristine, glucocorticoid, etoposide.

OUTCOMES

The patient achieved complete remission and a disease-free survival of 52 months.

LESSONS

HPS and its potential diseases should be diagnosed and treated as soon as possible. Clinicians should be aware of the presence of lymphoma in patients with HPS. Rituximab plays an important role in the prognosis of HPS, particularly Epstein-Barr virus positivity. Cyclophosphamide, epirubicin, vincristine, glucocorticoid remains an effective regimen for the treatment of T-cell LAPS. This study provides a better understanding of the diagnosis and treatment of LAPS.

Treatment Strategies for Central Nervous System Effects in Primary and Secondary Haemophagocytic Lymphohistiocytosis in Children

Purpose of Review

This review presents an appraisal of current therapeutic options for the treatment of central nervous system haemophagocytic lymphohistiocytosis (CNS-HLH) in the context of systemic disease, as well as when CNS features occur in isolation. We present the reader with a diagnostic approach to CNS-HLH and commonly used treatment protocols. We discuss and evaluate newer treatments on the horizon.

Recent Findings

Mortality is high in patients who do not undergo HSCT, and while larger studies are required to establish benefit in many treatments, a number of new treatments are currently being evaluated. Alemtuzumab is being used as a first-line treatment for CNS-HLH in a phase I/II multicentre prospective clinical trial as an alternative to traditional HLH-1994 and 2004 protocols. It has also been used successfully as a second-line agent for the treatment of isolated CNS-HLH that is refractory to standard treatment. Ruxolitinib and emapalumab are new immunotherapies that block the Janus kinase—Signal Transducer and Activator of Transcription (JAK-STAT) pathway that have shown efficacy in refractory HLH, including for CNS-HLH disease.

Summary

Treatment of CNS-HLH often requires HLH-94 or 2004 protocols followed by haematopoietic stem cell transplantation (HSCT) to maintain remission, although relapse can occur, particularly with reduced intensity conditioning if donor chimerism falls. CNS features have been shown to improve or stabilise following HSCT in CNS-HLH in the context of systemic disease and in isolated CNS-HLH. Encouraging reports of early cohort studies suggest alemtuzumab and the Janus kinase (JAK) inhibitor ruxolitinib offer potential salvage therapy for relapsed and refractory CNS-HLH. Newer immunotherapies such as tocilizumab and natalizumab have been shown to be beneficial in sporadic cases. CNS-HLH due to primary gene defects may be amenable to gene therapy in the future.

Disseminated tuberculosis complicated by hemophagocytic lymphohistiocytosis in an immunocompetent adult with favorable outcomes: A case report

Hemophagocytic lymphohistiocytosis (HLH) is an uncommon hyperinflammatory syndrome characterized by excessive activation of macrophages and T-cells with high cytokines levels, causing multiorgan dysfunction.HLH has been associated with variable infectious etiologies, such as tuberculosis(TB). TB-associated HLH (TB-HLH) is a rare condition, but it is fatal if not treated. The diagnosis of TB-HLH is challenging and might be missed if not highly considered. The classic manifestations of HLH include pancytopenia, organomegaly, lymphadenopathy, and coagulopathy. Herein, we present a young immunocompetent adult diagnosed with disseminated TB complicated by HLH. Our patient responded well to the combination of antituberculosis therapy(ATT), corticosteroid, and intravenous immunoglobulin(IVIG). This case highlights the importance of considering this fatal complication in TB patients.

Digenic Inheritance: Evidence and Gaps in Hemophagocytic Lymphohistiocytosis

Hemophagocytic lymphohistiocytosis (HLH) is a hyperinflammatory disorder characterized by the inability to properly terminate an immune response. Familial HLH (FHLH) and related immune dysregulation syndromes are associated with mutations in the genes PRF1, UNC13D, STX11, STXBP2, LYST, AP3B1, and RAB27A, all of which are required for the assembly, exocytosis, and function of cytotoxic granules within CD8+ T cells and natural killer (NK) cells. Loss-of-function mutations in these genes render the cytotoxicity pathway ineffective, thereby failing to eradicate immune stimuli, such as infectious pathogens or malignant cells. The resulting persistent immune system stimulation drives hypercytokinemia, ultimately leading to severe tissue inflammation and end-organ damage. Traditionally, a diagnosis of FHLH requires the identification of biallelic loss-of-function mutations in one of these degranulation pathway genes. However, this narrow definition fails to encompass patients with other genetic mechanisms underlying degranulation pathway dysfunction. In particular, mounting clinical evidence supports a potential digenic mode of inheritance of FHLH in which single loss-of-function mutations in two different degranulation pathway genes cooperate to impair pathway activity. Here, we review the functions of the FHLH-associated genes within the degranulation pathway and summarize clinical evidence supporting a model in which cumulative defects along this mechanistic pathway may underlie HLH.

Prognostic death factors in secondary hemophagocytic lymphohistiocytosis children with multiple organ dysfunction syndrome receiving continuous renal replacement therapy: A multicenter prospective nested case-control study

Introduction

Multiple organ dysfunction syndrome (MODS) with secondary hemophagocytic lymphohistiocytosis (SHLH) causes significant mortality. We aimed to identify the predictor factors for death in pediatric patients with SHLH‐associated MODS receiving continuous renal replacement therapy (CRRT).

Methods

This multicentered nested case–control study was conducted from 2016 to 2020. The characteristics were compared between survivors and non‐survivors. Logistic regression was applied to identify the risk factors for death. The cutoff values were assessed by receiver operating characteristics curves.

Results

Fifty two patients were enrolled in this study. Interleukin‐6 level (p = 0.018) and the number of organ dysfunction (p = 0.047) were independent risk factors for death. The cutoff value of 13.12 pg/ml interleukin‐6 and three organs dysfunction at CRRT initiation presented a high sensitivity and specificity.

Conclusion

The number of organ dysfunction and interleukin‐6 at CRRT initiation are independent risk factors for death in pediatric patients with SHLH‐associated MODS.

Graft-versus-host disease after liver transplantation is associated with bone marrow failure, hemophagocytosis, and DNMT3A mutations

Graft-versus-host disease after liver transplantation (LT-GVHD) is rare, frequently fatal, and associated with bone marrow failure (BMF), cytopenias, and hyperferritinemia. Given hyperferritinemia and cytopenias are present in hemophagocytic lymphohistiocytosis (HLH), and somatic mutations in hematopoietic cells are associated with hyperinflammatory responses (clonal hematopoiesis of indeterminate potential, CHIP), we identified the frequency of hemophagocytosis and CHIP mutations in LT-GVHD. We reviewed bone marrow aspirates and biopsies, quantified blood/marrow chimerism, and performed next-generation sequencing (NGS) with a targeted panel of genes relevant to myeloid malignancies, CHIP, and BMF. In all, 12 marrows were reviewed from 9 LT-GVHD patients. In all, 10 aspirates were evaluable for hemophagocytosis; 7 had adequate DNA for NGS. NGS was also performed on marrow from an LT cohort (n = 6) without GVHD. Nine of 10 aspirates in LT-GVHD patients showed increased hemophagocytosis. Five (71%) of 7 with LT-GVHD had DNMT3A mutations; only 1 of 6 in the non-GVHD LT cohort demonstrated DNMT3A mutation (p = .04). Only 1 LT-GVHD patient survived. BMF with HLH features was associated with poor hematopoietic recovery, and DNMT3A mutations were over-represented, in LT-GVHD patients. Identification of HLH features may guide prognosis and therapeutics. Further studies are needed to clarify the origin and impact of CHIP mutations on the hyperinflammatory state.

The prevalence and prognosis of hyponatraemia in non-Hodgkin lymphoma-associated hemophagocytic lymphohistiocytosis

Non-Hodgkin lymphoma associated hemophagocytic lymphohistiocytosis (NHL-HLH) in adult secondary HLH is a common and universally highly lethal critical disorder. Hyponatraemia is the most common electrolyte disorder in the critical illness setting and acts as a negative prognostic factor. The aim of our study was to evaluate the prognostic role of hyponatraemia among patients with NHL-HLH. The results showed that 81 (52.9%) patients had hyponatraemia. After a median follow up 47 (range 14-180) days, there were 72 (88.9%) cumulative deaths in hyponatraemia group while 50 (69.4%) in normonatremia group. After adjustment for confounders, multivariate analysis revealed that hyponatraemia was an independent prognostic factor for OS (HR:1.51, 95% CI: 1.03-2.20; p = 0.033). Restricted cubic spline confirmed a linear and positive association between serum sodium and the risk of mortality. Hyponatraemia is relatively frequent in NHL-HLH. As a readily available biomarker in clinical routine, it was a promising prognostic predictor for NHL-HLH.

Interferon gamma immunotherapy in five critically ill COVID-19 patients with impaired cellular immunity: A case series

BACKGROUND

Prolonged severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) shedding has been described in immunocompromised coronavirus disease 2019 (COVID-19) patients, resulting in protracted disease and poor outcome. Specific therapy to improve viral clearance and outcome for this group of patients is currently unavailable.

METHODS

Five critically ill COVID-19 patients with severe defects in cellular immune responses, high SARS-CoV-2 viral RNA loads, and no respiratory improvement were treated with interferon gamma, 100 μg subcutaneously, thrice weekly. Bronchial secretion was collected every 48 h for routine diagnostic SARS-CoV-2 RT-PCR and viral culture.

FINDINGS

Interferon gamma administration was followed by a rapid decline in SARS-CoV-2 load and a positive-to-negative viral culture conversion. Four patients recovered, and no signs of hyperinflammation were observed.

CONCLUSIONS

Interferon gamma may be considered as adjuvant immunotherapy in a subset of immunocompromised COVID-19 patients.

FUNDING

A.v.L. and R.v.C. are supported by National Institutes of Health (R01AI145781). G.J.O. and R.P.v.R. are supported by a VICI grant (016.VICI.170.090) from the Dutch Research Council (NWO). W.F.A. is supported by a clinical fellowship grant (9071561) of Netherlands Organization for Health Research and Development. M.G.N. is supported by an ERC advanced grant (833247) and a Spinoza grant of the Netherlands Organization for Scientific Research.

Chronic active Epstein-Barr virus-associated secondary hemophagocytic lymphohistiocytosis in pregnancy: a case report

BACKGROUND

Secondary hemophagocytic lymphohistiocytosis (sHLH) is a rare and fatal disease characterized by uncontrolled immune cell activation that can lead to a cytokine storm. Unfortunately, this condition can occur even during pregnancy, threatening both maternal and fetal lives.

CASE PRESENTATION

A 23-year-old nulliparous woman at 26 weeks of gestation presented with continuous fever, coughing, and sore throat. Upon arrival at our hospital, her temperature was >38°C and laboratory findings indicated cytopenia (neutrophil count, 779/μL; hemoglobin level, 10.2 g/dL; platelet count, 29,000/μL), elevated ferritin level (1,308 ng/mL), and elevated soluble interleukin-2 receptor level (11,200 U/mL). Computed tomography showed marked splenomegaly. Bone marrow examination revealed hemophagocytosis, and blood examination showed a plasma Epstein-Barr virus (EBV) DNA level of 8.9 × 10⁵ copies/μg. The monoclonal proliferation of EBV-infected T cells was confirmed by Southern blotting, and the patient was diagnosed with chronic active EBV-associated sHLH and T-cell lymphoproliferative disease. Immediately after admission, the patient's condition suddenly deteriorated. She developed shock and disseminated intravascular coagulation, requiring endotracheal intubation along with methylprednisolone pulse and etoposide therapy. Although the patient recovered, she delivered a stillborn baby. After delivery, she was treated with reduced-dose dexamethasone, etoposide, ifosfamide, and carboplatin (DeVIC) and steroid (dexamethasone), methotrexate, ifosfamide, L-asparaginase, and etoposide (SMILE) chemotherapies. Five months after diagnosis, she received human leukocyte antigen-haploidentical allogeneic bone marrow transplantation from her sister. She remains in remission for 5 months from the time of transplantation to the present.

CONCLUSIONS

sHLH, which may cause maternal and fetal death, should be carefully considered in critically ill pregnant women, particularly those presenting with continuous fever and cytopenia.

Cleavage of DNA and RNA by PLD3 and PLD4 limits autoinflammatory triggering by multiple sensors

Phospholipase D3 (PLD3) and PLD4 polymorphisms have been associated with several important inflammatory diseases. Here, we show that PLD3 and PLD4 digest ssRNA in addition to ssDNA as reported previously. Moreover, Pld3^−/−Pld4^−/− mice accumulate small ssRNAs and develop spontaneous fatal hemophagocytic lymphohistiocytosis (HLH) characterized by inflammatory liver damage and overproduction of Interferon (IFN)-γ. Pathology is rescued in Unc93b1^3d/3dPld3^−/−Pld4^−/− mice, which lack all endosomal TLR signaling; genetic codeficiency or antibody blockade of TLR9 or TLR7 ameliorates disease less effectively, suggesting that both RNA and DNA sensing by TLRs contributes to inflammation. IFN-γ made a minor contribution to pathology. Elevated type I IFN and some other remaining perturbations in Unc93b1^3d/3dPld3^−/−Pld4^−/− mice requires STING (Tmem173). Our results show that PLD3 and PLD4 regulate both endosomal TLR and cytoplasmic/STING nucleic acid sensing pathways and have implications for the treatment of nucleic acid-driven inflammatory disease.

Loss of function polymorphisms of phospholipase D3 and D4 are associated with inflammatory diseases and their function is unclear. Here the authors show that PLD3/4 function as RNAses and deletion of these proteins in mice leads to accumulation of ssRNA which exacerbates inflammation through TLR signalling.

Consensus-Based Guidelines for the Recognition, Diagnosis, and Management of Hemophagocytic Lymphohistiocytosis in Critically Ill Children and Adults

OBJECTIVE

Hemophagocytic lymphohistiocytosis is a hyperinflammatory syndrome that often requires critical care support and remains difficult to diagnose. These guidelines are meant to aid in the early recognition, diagnosis, supportive care, and treatment of patients with hemophagocytic lymphohistiocytosis in ICUs.

DATA SOURCES

The literature searches were performed with PubMed (MEDLINE).

STUDY SELECTION

Keywords and medical subject headings terms for literature search included "macrophage activation syndrome," hemophagocytic lymphohistiocytosis," and "hemophagocytic syndrome."

DATA EXTRACTION

The Histiocyte Society developed these consensus recommendations on the basis of published reports and expert opinions with level of evidence provided for each recommendation. They were endorsed by the Society of Critical Care Medicine.

DATA SYNTHESIS

Testing for hemophagocytic lymphohistiocytosis should be initiated promptly in all patients admitted to ICUs with an unexplained or disproportionate inflammatory response, especially those with rapid clinical deterioration. Meeting five or more of eight hemophagocytic lymphohistiocytosis 2004 diagnostic criteria serves as a valuable diagnostic tool for hemophagocytic lymphohistiocytosis. Early aggressive critical care interventions are often required to manage the multisystem organ failure associated with hemophagocytic lymphohistiocytosis. Thorough investigation of the underlying triggers of hemophagocytic lymphohistiocytosis, including infections, malignancies, and autoimmune/autoinflammatory diseases, is essential. Early steroid treatment is indicated for patients with familial hemophagocytic lymphohistiocytosis and is often valuable in patients with acquired hemophagocytic lymphohistiocytosis (i.e., secondary hemophagocytic lymphohistiocytosis) without previous therapy, including macrophage activation syndrome (hemophagocytic lymphohistiocytosis secondary to autoimmune/autoinflammatory disease) without persistent or relapsing disease. Steroid treatment should not be delayed, particularly if organ dysfunction is present. In patients with macrophage activation syndrome, whose disease does not sufficiently respond, interleukin-1 inhibition and/or cyclosporine A is recommended. In familial hemophagocytic lymphohistiocytosis and severe, persistent, or relapsing secondary macrophage activation syndrome, the addition of prompt individualized, age-adjusted etoposide treatment is recommended.

CONCLUSIONS

Further studies are needed to determine optimal treatment for patients with hemophagocytic lymphohistiocytosis in ICUs, including the use of novel and adjunct therapies.

Clinical Characteristics of Adult Hemophagocytic Lymphohistiocytosis in the Emergency Department

Purpose

To determine the clinical manifestations and results of adult hemophagocytic lymphohistiocytosis (HLH) patients in our emergency department.

Methods

We retrospectively evaluated patients with HLH from 1 April 2018 to 31 December 2020. The clinical data of these patients (basic information, symptoms, vital signs, laboratory results, HLH diagnostic criteria, H Score, main treatments, outcomes) were collected.

Results

Thirty-three patients (23 males and 10 females; 40.55±18.78 years) with 34 clinical episodes (one male had two clinical episodes and died during the second episode) were enrolled. Twenty-five patients were placed in a “survivor” group, and nine patients were categorized into a “deceased” group. Fever, splenomegaly, hemoglobin <90 g/L and platelet count <100×10⁹/L most commonly met the diagnostic standard for HLH. The H Score results in the survival group and deceased group was 212.4±37.18 and 252.1±40.95, respectively. Viral infection was the most common reason for HLH, followed by immune-system disease and cancer. Laboratory tests showed that deceased-group patients had multiple-organ dysfunction. Multivariate logistic regression showed that the lactate dehydrogenase (lactate dehydrogenase) level (P = 0.039; odds ratio, 0.999) was significantly related to death.

Conclusion

In the emergency department, HLH should be considered for critically ill patients with fever, splenomegaly, low hemoglobin and low platelet count. The H Score might be useful to diagnose HLH quickly. In our study, 26.47% of HLH patients died in the emergency department, and patients with a significantly increased lactate dehydrogenase level had a markedly increased risk of death.

A validation study of the identification of haemophagocytic lymphohistiocytosis in England using population-based health data

We assessed the validity of coded healthcare data to identify cases of haemophagocytic lymphohistiocytosis (HLH). Hospital Episode Statistics (HES) identified 127 cases within five hospital Trusts 2013-2018 using ICD-10 codes D76.1, D76.2 and D76.3. Hospital records were reviewed to validate diagnoses. Out of 74 patients, 73 were coded D76.1 or D76.2 (positive predictive value 89·0% [95% Confidence Interval {CI} 80·2-94·9%]) with confirmed/probable HLH. For cases considered not HLH, 44/53 were coded D76.3 (negative predictive value 97·8% [95% CI 88·2-99·9%]). D76.1 or D76.2 had 68% sensitivity in detecting HLH compared to an established active case-finding HLH register in Sheffield. Office for National Statistics (ONS) mortality data (2003-2018) identified 698 patients coded D76.1, D76.2 and D76.3 on death certificates. Five hundred and forty-one were coded D76.1 or D76.2 of whom 524 (96·9%) had HLH in the free-text cause of death. Of 157 coded D76.3, 66 (42·0%) had HLH in free text. D76.1 and D76.2 codes reliably identify HLH cases, and provide a lower bound on incidence. Non-concordance between D76.3 and HLH excludes D76.3 as an ascertainment source from HES. Our results suggest electronic healthcare data in England can enable population-wide registration and analysis of HLH for future research.

The cytokine storms of COVID-19, H1N1 influenza, CRS and MAS compared. Can one sized treatment fit all?

An analysis of published data appertaining to the cytokine storms of COVID-19, H1N1 influenza, cytokine release syndrome (CRS), and macrophage activation syndrome (MAS) reveals many common immunological and biochemical abnormalities. These include evidence of a hyperactive coagulation system with elevated D-dimer and ferritin levels, disseminated intravascular coagulopathy (DIC) and microthrombi coupled with an activated and highly permeable vascular endothelium. Common immune abnormalities include progressive hypercytokinemia with elevated levels of TNF-α, interleukin (IL)-6, and IL-1β, proinflammatory chemokines, activated macrophages and increased levels of nuclear factor kappa beta (NFκB). Inflammasome activation and release of damage associated molecular patterns (DAMPs) is common to COVID-19, H1N1, and MAS but does not appear to be a feature of CRS. Elevated levels of IL-18 are detected in patients with COVID-19 and MAS but have not been reported in patients with H1N1 influenza and CRS. Elevated interferon-γ is common to H1N1, MAS, and CRS but levels of this molecule appear to be depressed in patients with COVID-19. CD4+ T, CD8+ and NK lymphocytes are involved in the pathophysiology of CRS, MAS, and possibly H1N1 but are reduced in number and dysfunctional in COVID-19. Additional elements underpinning the pathophysiology of cytokine storms include Inflammasome activity and DAMPs. Treatment with anakinra may theoretically offer an avenue to positively manipulate the range of biochemical and immune abnormalities reported in COVID-19 and thought to underpin the pathophysiology of cytokine storms beyond those manipulated via the use of, canakinumab, Jak inhibitors or tocilizumab. Thus, despite the relative success of tocilizumab in reducing mortality in COVID-19 patients already on dexamethasone and promising results with Baricitinib, the combination of anakinra in combination with dexamethasone offers the theoretical prospect of further improvements in patient survival. However, there is currently an absence of trial of evidence in favour or contravening this proposition. Accordingly, a large well powered blinded prospective randomised controlled trial (RCT) to test this hypothesis is recommended.

Monocyte-driven atypical cytokine storm and aberrant neutrophil activation as key mediators of COVID-19 disease severity

Epidemiological and clinical reports indicate that SARS-CoV-2 virulence hinges upon the triggering of an aberrant host immune response, more so than on direct virus-induced cellular damage. To elucidate the immunopathology underlying COVID-19 severity, we perform cytokine and multiplex immune profiling in COVID-19 patients. We show that hypercytokinemia in COVID-19 differs from the interferon-gamma-driven cytokine storm in macrophage activation syndrome, and is more pronounced in critical versus mild-moderate COVID-19. Systems modelling of cytokine levels paired with deep-immune profiling shows that classical monocytes drive this hyper-inflammatory phenotype and that a reduction in T-lymphocytes correlates with disease severity, with CD8+ cells being disproportionately affected. Antigen presenting machinery expression is also reduced in critical disease. Furthermore, we report that neutrophils contribute to disease severity and local tissue damage by amplification of hypercytokinemia and the formation of neutrophil extracellular traps. Together our findings suggest a myeloid-driven immunopathology, in which hyperactivated neutrophils and an ineffective adaptive immune system act as mediators of COVID-19 disease severity.

Quantitative analysis of the natural history of prolidase deficiency: description of 17 families and systematic review of published cases

PURPOSE

Prolidase deficiency is a rare inborn error of metabolism causing ulcers and other skin disorders, splenomegaly, developmental delay, and recurrent infections. Most of the literature is constituted of isolated case reports. We aim to provide a quantitative description of the natural history of the condition by describing 19 affected individuals and reviewing the literature.

METHODS

Nineteen patients were phenotyped per local institutional procedures. A systematic review following PRISMA criteria identified 132 articles describing 161 patients. Main outcome analyses were performed for manifestation frequency, diagnostic delay, overall survival, symptom-free survival, and ulcer-free survival.

RESULTS

Our cohort presented a wide variability of severity. Autoimmune disorders were found in 6/19, including Crohn disease, systemic lupus erythematosus, and arthritis. Another immune finding was hemophagocytic lymphohistiocytosis (HLH). Half of published patients were symptomatic by age 4 and had a delayed diagnosis (mean delay 11.6 years). Ulcers were present initially in only 30% of cases, with a median age of onset at 12 years old.

CONCLUSION

Prolidase deficiency has a broad range of manifestations. Symptoms at onset may be nonspecific, likely contributing to the diagnostic delay. Testing for this disorder should be considered in any child with unexplained autoimmunity, lower extremity ulcers, splenomegaly, or HLH.