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Flea-borne typhus (FBT), also known as murine typhus, is a zoonotic infection caused by R. typhi with world-wide distribution. In the United States, the infection is uncommon but remains endemic in some areas, including Los Angeles County. It typically manifests as a benign acute febrile illness but can be complicated in a minority of cases. Associated hemophagocytic lymphohistiocytosis (HLH) has been described in a limited number of cases. Here, we present a case of a patient with FBT complicated by HLH treated empirically with doxycycline with subsequent resolution of HLH. Also included is a review of the literature of other published cases.

Hemophagocytic lymphohistiocytosis (HLH) is a life-threatening hyperinflammatory disorder that occurs as a consequence of immune dysregulation. HLH can be primary (familial or non-familial) or secondary to infection, autoimmune disease or malignancy. Malignancy-associated HLH is often accompanied by hematologic and lymphoid neoplasms. This report describes the case of a 3-year-old girl with an initial diagnosis of acute lymphoblastic leukemia who subsequently developed HLH during primary chemotherapy. She was admitted with a pulmonary infection, and initial blood tests showed thrombocytopenia and anemia. Whole-exome sequencing of gene and whole transcriptome RNA sequencing data indicated mutations of UNC13D. The hospital course was complicated by multiple infections, altered mental status and acute respiratory distress syndrome. HLH secondary to multiple infections that achieved remission following targeted therapy with ruxolitinib, in conjunction with corticosteroids and other complementary treatments. This report provides a synopsis of the diagnostic and treatment procedures implemented in this case. [ABSTRACT FROM AUTHOR]

Background: Subcutaneous panniculitis-like T-cell lymphoma (SPTCL) is a rare subtype of non-Hodgkin lymphoma associated with hemophagocytic lymphohistiocytosis (HLH)/HLH-like systemic illnesses and germline HAVCR2 mutations. Although previous studies suggested successful treatment of SPTCL with immunosuppressive therapy (IST) without chemotherapy, IST data in pediatric SPTCL remain scarce. To explore characteristics and therapeutic outcomes, comparing IST-based and chemotherapy-based regimens in pediatric SPTCL, in this retrospective cohort study, patients with SPTCL diagnosed at age ≤20 years during 2007-2023 were enrolled from 6 hematology/oncology centers in Thailand. HAVCR2 exon 2 sequencing was performed using DNA extracted from peripheral blood or bone marrow. Presence of HLH/HLH-like systemic illnesses, treatment outcomes, and adverse events (AEs) were reviewed and analyzed. Results: Of 22 patients with SPTCL (median age at diagnosis, 11.5 years [range, 6.0-19.0]; 63.6% males), 86.4% harbored germline HAVCR2 mutation, either homozygous (77.3%) or heterozygous (9.1%) p.Y82C variant, while 68.2% developed HLH/HLH-like systemic illnesses. Overall, 36.4% received IST as first-line treatment. Durable complete remission (CR) was achieved in 71.4% and 50.0% after first-line chemotherapy and IST, respectively (P=0.45); however, chemotherapy tended to increase any AEs compared to IST (57.1% vs. 12.5%; P=0.07). The most common AEs were hypertension (27.3%), febrile neutropenia (18.2%), and fungal infection (13.6%). Among the relapsed cases, 71.4% could reach CR after subsequent-line therapy. Fatality (4.5%) only occurred in the chemotherapy group. Conclusions: Pediatric SPTCL in Thailand frequently involves germline HAVCR2 mutations and/or HLH/HLH-like systemic illnesses. With comparable response and modest therapy-related toxicity, IST-based regimens may alternatively be considered as first-line treatment for pediatric SPTCL. [ABSTRACT FROM AUTHOR]

Chimeric antigen receptor (CAR) T-cell therapy represents a highly efficacious treatment modality demonstrated to enhance outcomes in patients afflicted with malignancies, particularly those enduring relapsed or refractory hematological malignancies. However, the escalating adoption of CAR T-cell therapy has unveiled several life-threatening toxicities, notably cytokine release syndrome (CRS), immune effector cell-associated neurotoxicity syndrome (ICANS), infections, and hematological toxicities (HTs), thereby hindering the broad implementation of CAR T-cell therapy. HTs encompass a spectrum of adverse effects, including cytopenias, hemophagocytic lymphohistiocytosis (HLH), coagulopathies, and B-cell aplasia. While our comprehension of the underlying mechanisms governing CRS and ICANS is advancing, the intricate pathophysiology of HTs remains inadequately elucidated. Such knowledge gaps may precipitate suboptimal therapeutic decisions, potentially culminating in substantial medical resource depletion and detriment to patients' quality of life. In this comprehensive review, based on recent updated findings, we delineate various mechanisms contributing to HTs subsequent to CAR T-cell therapy, explicate manifestations of HTs, and proffer strategic interventions to mitigate this relevant clinical challenge. [ABSTRACT FROM AUTHOR]

Fever is common in the ICU, with infectious causes accounting for only half of febrile episodes. This case examines a young male who developed high‐grade fevers and pulmonary infiltrates unresponsive to broad‐spectrum antibiotics. Examination revealed hepatosplenomegaly, hypertriglyceridemia, anemia, and thrombocytopenia, suggestive of hemophagocytic lymphohistiocytosis (HLH). Meeting 5 of 8 HLH criteria, high‐dose steroids were administered, resulting in clinical improvement. HLH, with a high mortality risk, demands early recognition, complicated by nonspecific symptoms. This case highlights the rare manifestation of ARDS in HLH, adding diagnostic challenges in critical care settings. [ABSTRACT FROM AUTHOR]

Purpose: GATA2 deficiency is an autosomal dominant disease that manifests with a range of clinical symptoms, including increased susceptibility to viral, bacterial, and fungal infections. Furthermore, the increased susceptibility to infections in GATA2 deficiency can trigger hemophagocytic lymphohistiocytosis (HLH) in these patients. Our systematic review evaluates reported cases of GATA2 deficiency and HLH in the literature. Methods: A systematic review of case reports was conducted following PRISMA 2020 guidelines, encompassing studies retrieved from Ovid MEDLINE ALL, Embase via Ovid SP, Scopus, Web of Science, and Google Scholar from inception until June 14, 2024. This review included studies reporting patients diagnosed with GATA2 deficiency or having a documented history of the condition, who subsequently developed or were concurrently diagnosed with HLH. Various study types were considered, such as case reports, case series, letters to editors, original articles, correspondences, and commentaries, without any restrictions on language. Results: In our systematic review, 15 studies from 2016 to 2024 were analyzed, encompassing 23 patients with GATA2 deficiency and HLH. the mean (SD) age of patients was 23.48 (10.54) years, ranging from 7 to 57 years. These patients exhibited diverse genetic mutations and a spectrum of infections, particularly Mycobacterium avium (M. avium), Mycobacterium kansasii (M. kansasii), Epstein-Barr virus (EBV), cytomegalovirus (CMV), varicella-zoster virus (VZV), herpes simplex virus (HSV), and influenza A, often leading to HLH. Family histories of GATA2-deficient patients with HLH occasionally reveal confirmed GATA2 mutations or suspicious cases among first-degree relatives. Hematopoietic stem cell transplantation (HSCT) was performed in 8 patients with GATA2 deficiency and HLH. Among them, 6 patients survived post-therapy, while 2 patients died following HSCT. Currently, 1 patient is being considered for HSCT. The overall mortality rate among GATA2 deficiency patients who experienced HLH was 39.13%. Conclusions: This systematic review highlights GATA2 deficiency's association with diverse infections triggering HLH, emphasizing early infection management to mitigate mortality risks. This comprehensive analysis contributes to scientific knowledge, offering important insights for clinicians and researchers in diagnosing and managing this rare condition. [ABSTRACT FROM AUTHOR]

The article presents a case study of a 6-month-old African American girl diagnosed with familial hemophagocytic lymphohistiocytosis (HLH) triggered by enterovirus, characterized by prolonged fever, pancytopenia, and abnormal liver function. Topics include the diagnostic criteria and challenges of HLH, the therapeutic strategies employed to manage the condition, and genetic underpinnings associated with PRF1 mutations, which affect the perforin protein critical for immune response regulation.

Objective: Adult‐onset Still's disease (AOSD) and secondary hemophagocytic lymphohistiocytosis (sHLH) are both hyperferritinemic cytokine storm syndromes that can be difficult to distinguish from each other in hospitalized patients. The objective of this study was to compare the inflammatory markers ferritin, D‐dimer, C‐reactive protein (CRP), and soluble CD25 (sCD25) in patients with AOSD and sHLH. These four markers were chosen as they are widely available and represent different aspects of inflammatory diseases: macrophage activation (ferritin); endothelialopathy (D‐dimer); interleukin‐1/interleukin‐6/tumour necrosis factor elevation (CRP) and T cell activation (sCD25). Methods: This was a single‐center retrospective study. Patients diagnosed by the Hematology service at Vancouver General Hospital for AOSD or sHLH from 2009 to 2023 were included. Results: There were 16 AOSD and 44 sHLH patients identified. Ferritin was lower in AOSD than HLH (median 11 360 μg/L vs. 29 020 μg/L, p =.01) while D‐dimer was not significantly different (median 5310 mg/L FEU vs. 7000 mg/L FEU, p =.3). CRP was higher (median 168 mg/L vs. 71 mg/L, p <.01) and sCD25 was lower (median 2220 vs. 7280 U/mL, p =.004) in AOSD compared to HLH. The combined ROC curve using CRP >130 mg/L and sCD25< 3900 U/mL to distinguish AOSD from HLH had an area under the curve (AUC) of 0.94 (95% confidence interval 0.93–0.97) with sensitivity 91% and specificity 93%. Conclusions: These findings suggest that simple, widely available laboratory tests such as CRP and sCD25 can help clinicians distinguish AOSD from HLH in acutely ill adults with extreme hyperferritinemia. Larger studies examining a wider range of clinically available inflammatory biomarkers in a more diverse set of cytokine storm syndromes are warranted. [ABSTRACT FROM AUTHOR]

Secondary hemophagocytic lymphohistiocytosis (sHLH) is a hyperinflammatory syndrome characterized by immune disorders. It is imperative to elucidate the immunophenotypic panorama and the interactions among these cells in patients. Human peripheral blood mononuclear cells were collected from healthy donors and sHLH patients and tested using multicolor flow cytometry. We used FlowSOM to explore and visualize the immunophenotypic characteristics of sHLH. By demonstrating the phenotypes of immune cells, we discovered that sHLH patients had significantly higher levels of CD56+ monocytes, higher levels of myeloid-derived suppressor cells, low-density neutrophil-to-T cell ratio, and higher heterogeneous T cell activation than healthy donors. However, natural killer cell cytotoxicity and function were impaired. We then assessed the correlations among 30 immune cell types and evaluated metabolic analysis. Our findings demonstrated polymorphonuclear myeloid-derived suppressor cells, CD56+ monocytes, and neutrophil-to-T cell ratio were elevated abnormally in sHLH patients, which may indicate an association with immune overactivation and inflammatory response. We are expected to confirm that they are involved in the occurrence of the disease through further in-depth research. [ABSTRACT FROM AUTHOR]

The characteristic expansion of T CD38high/HLA‐DR+CD8+ lymphocytes observed in hemophagocytic lymphohistiocytosis (HLH) and macrophage activation syndrome (MAS) proved able to distinguish HLH/MAS from sepsis and systemic juvenile idiopathic arthritis. However, the performance of this marker in differentiating HLH/MAS from other pediatric febrile conditions with similar clinical onset and yet entirely different treatments remains unexplored. CD38high/HLA‐DR+CD8+ frequencies measured in the peripheral fresh blood of pediatric patients attended for suspicion of HLH/MAS were retrospectively recorded and clinical characteristics were retrieved. CD38high/HLA‐DR+CD8+ frequencies in HLH/MAS patients (15 patients; median: 22.0%, IQR: 11.0–49.0%) were compared with those who presented febrile conditions other‐than‐HLH (28 patients; median: 13.0%, IQR: 3.9–28.7%; p = 0.24). HLH and non‐HLH patients were subsequently regrouped based on the presence of an identified infection (22 patients; median: 27.0%, IQR: 15.2‐72.1%) and compared with those without infections (21 patients; median: 7.6%, IQR: 3.7–24.3%; p = 0.0035). CD38high/HLA‐DR+CD8+ percentages were significantly higher only in the infection group compared with the noninfection one, with a patent pathogen‐specific expansion in Epstein–Barr virus primoinfection and visceral leishmaniasis regardless of the presence of HLH. CD38high/HLA‐DR+CD8+ frequencies do not appear as an HLH‐specific marker as they naturally expand in other clinical situations that are common in childhood and may mimic HLH initial presentation. [ABSTRACT FROM AUTHOR]

Background Haemophagocytic lymphohistiocytosis (HLH) is a rare complication of dengue fever with potentially life-threatening consequences and high mortality. Therefore, this study aims to investigate the prevalence, management and outcome of HLH in dengue fever. Methods The major electronic databases, including PubMed, ScienceDirect and Ovid SP, were searched from inception until 31 January 2024 to identify relevant studies. Pooled prevalence and mortality were calculated using the random-effects generic inverse variance model with a 95% CI. All the statistical analysis was conducted using R programming. Results A total of nine studies with 157 patients with HLH, 576 patients with severe dengue and 5081 patients with dengue fever were included in this meta-analysis. The prevalence of HLH in severe dengue (22.1%, 95% CI 8.07 to 48.0%) was significantly higher than the prevalence in dengue fever (3.12%, 95% CI 0.37 to 21.9%). The prevalence of HLH in severe dengue was higher in the paediatric population (22.8%, 95% CI 3.9 to 68.4%) compared with the adult population (19.0%, 95% CI 3.0 to 63.9%). The overall mortality rate was 20.2% (95% CI 9.7 to 37.2%). Conclusion The prevalence of dengue-associated HLH was low in patients with dengue fever but is significantly higher in patients with severe dengue and a high mortality rate. [ABSTRACT FROM AUTHOR]

Introduction: Inborn errors of immunity (IEI) are a group of genetically heterogeneous disorders with a wide-ranging clinical phenotype, varying from increased predisposition to infections to dysregulation of the immune system, including autoimmune phenomena, autoinflammatory disorders, lymphoproliferation, and malignancy. Lymphoproliferative disorder (LPD) in IEI refers to the nodal or extra-nodal and persistent or recurrent clonal or non-clonal proliferation of lymphoid cells in the clinical context of an inherited immunodeficiency or immune dysregulation. The Epstein-Barr virus (EBV) plays a significant role in the etiopathogenesis of LPD in IEIs. In patients with specific IEIs, lack of immune surveillance can lead to an uninhibited proliferation of EBV-infected cells that may result in chronic active EBV infection, hemophagocytic lymphohistiocytosis, and LPD, particularly lymphomas. Areas covered: We intend to discuss the pathogenesis, diagnosis, and treatment modalities directed toward EBV-associated LPD in patients with distinct IEIs. Expert opinion: EBV-driven lymphoproliferation in IEIs presents a diagnostic and therapeutic problem that necessitates a comprehensive understanding of host–pathogen interactions, immune dysregulation, and personalized treatment approaches. A multidisciplinary approach involving immunologists, hematologists, infectious disease specialists, and geneticists is paramount to addressing the diagnostic and therapeutic challenges posed by this intriguing yet formidable clinical entity. [ABSTRACT FROM AUTHOR]

Background: Hemophagocytic lymphohistiocytosis (HLH) is characterized by immune dysregulation that results in an uncontrolled hyperinflammatory state. HLH is classified into two main categories: primary (familial) HLH and secondary (acquired) HLH. Secondary HLH can result from various underlying, including infection-associated hemophagocytic syndrome (IAHS) and macrophage activation syndrome (MAS) associated with rheumatologic disorders, among others. Epstein–Barr virus (EBV) often causes IAHS, but central nervous system (CNS) involvement is rare among systemic lupus erythematosus (SLE) patients. We report a case of EBV encephalitis associated with HLH in a patient with childhood-onset SLE. Case presentation: A 12-year-old girl had received a diagnosis of SLE 2 months before presentation. After a period of inactive disease on treatment, fever and seizures, with altered mental status and hallucinations, developed over several weeks. A complete blood cell count (CBC) revealed pancytopenia, accompanied by elevated levels of inflammatory markers: 86 mm/hr erythrocyte sedimentation rate, 8.9 mg/dl c-reactive protein, and 3,966 ng/mL of ferritin. The differential diagnosis included active neuropsychiatric SLE, CNS infection and neurological manifestations in secondary HLH, which could have represented either IAHS or MAS. Meropenem and acyclovir were initially administered for clinical acute encephalitis, followed by pulse methylprednisolone; however, the fever persisted, and another CBC revealed progressive cytopenia. A bone marrow study showed hypocellularity and active hemophagocytic activity, and intravenous immunoglobulin was additionally given due to the diagnosis of HLH. Cerebrospinal fluid (CSF) analysis showed 60/mm3 white blood cells (N 55%, L 45%), 141 mg/dL glucose (0.7 blood-CSF glucose ratio), < 4 mg/dL protein; results of Gram stain and bacterial culture were negative. The viral encephalitis panel from the CSF confirmed EBV infection. Bone marrow immunohistochemistry examination revealed increasing levels of CD8 + T-cell and equivocal positive results for EBV-encoded RNA in situ hybridization; therefore, HLH potentially associated with EBV was diagnosed. After treatment with IVIg, cyclosporin A, and prednisolone, the patient's symptoms gradually improved and she was eventually able to return to school. Conclusions: Our case highlights the importance of a thorough differential diagnosis, including EBV encephalitis associated with HLH, in patients with childhood SLE, particularly in cases of clinical deterioration occurs after initial treatment. [ABSTRACT FROM AUTHOR]

UNC13 family (also known as Munc13) proteins are evolutionarily conserved proteins involved in the rapid and regulated secretion of vesicles, including synaptic vesicles and cytotoxic granules. Fast and regulated secretion at the neuronal and immunological synapses requires multiple steps, from the biogenesis of vesicles to membrane fusion, and a complex array of proteins for each step. Defects at these steps can lead to various genetic disorders. Recent studies have shown multiple roles of UNC13D in the secretion of cytotoxic granules by immune cells. Here, the molecular structure and detailed roles of UNC13D in the biogenesis, tethering, and priming of cytotoxic vesicles and in endoplasmic reticulum are summarized. Moreover, its association with immune diseases, including familial hemophagocytic lymphohistiocytosis type 3, macrophage activation syndrome, juvenile idiopathic arthritis, and autoimmune lymphoproliferative syndrome, is reviewed. Finally, the therapeutic application of CRISPR/Cas9-based gene therapy for genetic diseases is introduced. [ABSTRACT FROM AUTHOR]

Background: Hemophagocytic lymphohistiocytosis (HLH) is an inherited syndrome characterized by immune dysregulation. Central nervous system (CNS)-isolated disease is a rare presentation of familial HLH. We present a case of pediatric CNS-isolated HLH with a presentation complicated by unusual hemorrhagic intraparenchymal lesions. Case Presentation: A 15-year-old male presented with ataxia and MRI findings of multiple hemorrhagic lesions in his cerebral white matter, brainstem, and cerebellum, suggestive of vasculitis. After failing to improve with steroids and plasmapheresis, and progression to acute neurologic decompensation, new brainstem hemorrhages were noted. Further workup revealed 2 PRF1 mutations, confirming a diagnosis of familial CNS-HLH. He was later found to have a platelet granule defect, explaining his atypical neuroradiologic findings. The patient received treatment per the HLH-1994 protocol and underwent stem cell transplantation. Two years post-transplant, his perforin expression is nearly normal and his neurologic deficits have significantly improved. Conclusions: This case illustrates the variability in presentation of isolated CNS-HLH. Although rare, it is important to include this diagnosis on the differential in patients with CNS hemorrhagic lesions. If initial diagnostic studies remain inconclusive or response to early treatments is poor, CNS-HLH should be considered, as delay in diagnosis and treatment significantly affects morbidity and mortality. [ABSTRACT FROM AUTHOR]

Background: Allogeneic stem cell transplantation (allo-SCT) has seen limited use in treating multiple myeloma (MM), despite its potential to offer long-term survival or even cure through the graft-versus-myeloma effect. Its limited application is largely due to concerns over serious complications like infections and graft-versus-host disease (GVHD). The possibility of GVHD exacerbation when CAR-T cells are administered to patients previously treated with allo-SCT remains a topic of concern. Ciltacabtagene autoleucel (Cilta-cel) and idecabtagene vicleucel (Ide-cel) are CAR-T therapies that have been FDA-approved for relapsed/refractory (R/R) MM. A recent study using data from the CARTITUDE-1 trial has shown promising safety and efficacy of Cilta-Cel in patients with a prior history of allo-SCT. This report outlines our real-world experience with CAR-T treatment in such patients. The objective of this study is to assess the safety and effectiveness of CAR-T therapy in R/R MM patients who have previously undergone allo-SCT. Methods: We conducted a retrospective analysis of adult patients (18–70 years old) with R/R MM treated with CAR-T therapy as part of an institutional IRB-approved protocol. Data were collected on safety and efficacy outcomes from the institution's records. Adverse events (AEs) were evaluated using the National Cancer Institute Common Terminology Criteria for Adverse Events (NCI-CTCAE) version 5.0. Cytokine release syndrome (CRS) and immune effector cell-associated neurotoxicity syndrome (ICANS) were graded based on American Society for Transplantation and Cellular Therapy (ASTCT) criteria. Efficacy metrics included overall response rate (ORR) and progression-free survival (PFS), analyzed through the Kaplan–Meier method, with PFS defined as the time from CAR-T initiation to disease progression or death. Results: Of the 56 patients treated with CAR-T therapy, 8 (14.3%) had previously undergone allo-SCT. These patients had a median of seven prior therapy lines (LOTs), compared to five LOTs in the non-allo-SCT group (p = 0.04). CAR-T infusion occurred a median of 98.8 months after allo-SCT, with a range from 57.9 months to 178.5 months. CRS occurred in 87.5% of the allo-SCT group versus 77.1% in the non-allo-SCT group (p = 0.48). One patient in the allo-SCT group developed hemophagocytic lymphohistiocytosis (HLH), requiring anakinra. At a median follow-up of 4.8 months, the ORR was 87.5% in the allo-SCT group versus 75% in the non-allo-SCT group (p = 0.4). Median PFS had not been reached for the allo-SCT group at the time of analysis compared to 11.9 months in the non-allo-SCT group (p = 0.5). No treatment-related mortality or acute GVHD was noted in the allo-SCT cohort. Conclusions: The study suggests that prior allo-SCT does not adversely affect the safety or efficacy of CAR-T therapy in patients with R/R MM. These findings highlight the need for further investigations with larger patient samples and longer follow-up to better understand the interaction between allo-SCT and CAR-T therapy. [ABSTRACT FROM AUTHOR]

Background: Hemophagocytic lymphohistiocytosis (HLH) is a rare and life-threatening syndrome that can occur either in genetically predisposed individuals (primary HLH) or in particular conditions in immunocompromised patients (secondary HLH). Secondary HLH is very rare among solid organ transplant recipients, especially in lung transplant recipients, for whom its prognosis is dismal. Case Report: We report an exceptional case of HLH occurring unusually late following lung transplantation. At 11 years after transplantation, the patient, aged 67 years, presented with pancytopenia, fever, hyperferritinemia, and hypertriglyceridemia, along with splenomegaly. Exhaustive serological and PCR tests ruled out active infection. Bone marrow aspirates showed signs of hemophagocytosis, and bone marrow biopsy was suggestive of posttransplant lymphoproliferative disorder (PTLD). Timely treatment with etoposide and corticosteroids led to a transient improvement in the patient's clinical condition, and rituximab was initiated as a treatment for PTLD. Unfortunately, pancytopenia persisted for weeks, and the patient died from refractory septic shock, despite appropriate intravenous antibiotics. Autopsy revealed lymphoid infiltration of the mediastinal lymph nodes, liver and bone marrow, with some lymphocytes expressing CD3. A final diagnosis of Ann-Arbor stage IV non-EBVmediated monomorphic T-cell PTLD was established. Conclusions: This case report highlights a very unusual and fatal presentation of HLH in a lung transplant recipient, secondary to a T-cell PTLD. Indeed, HLH is typically seen as infection-related and reported to occur in the initial months following transplantation. To date, no guidelines or consensus exist regarding the management of immunosuppression regimen in solid organ transplantation. [ABSTRACT FROM AUTHOR]

Introduction: Adult-onset Still's disease is a rare systemic autoinflammatory disease. We present a case of a young man with a constellation of symptoms and myopericarditis as a complication of this disease. Case: A 36-year-old Hispanic man with no significant past medical history developed a quotidian fever pattern following an upper respiratory tract infection. He initially presented with chest pain concerning for myocardial infarction and underwent cardiac catheterization, which revealed non-obstructive coronary artery disease. He was found to have myopericarditis, significant neutrophilic leukocytosis, and hyperferritinemia. He improved on high-dose corticosteroids but developed steroid-induced psychosis, and 4 months from symptom onset, he finally received tocilizumab, which eventually induced remission without adverse reactions. Discussion: Adult-onset Still's disease should be considered in a patient with fevers of undetermined origin. Due to its multisystemic involvement, adult-onset Still's disease is often a diagnosis arrived at after an extensive cardiac, hematologic, malignant, and infectious workup. Imaging, laboratory testing, and bone marrow biopsy were necessary to rule out alternative etiologies of this patient's presentation. Steroids are the mainstay of treatment because they are easily affordable, although the high risk of adverse effects makes them less desirable. Interleukin-1 inhibitors (anakinra or canakinumab) and interleukin-6 inhibitor tocilizumab are the steroid-sparing biologic agents of choice but are cost-prohibitive. Conclusion: Adult-onset Still's disease should be considered in the differential diagnoses of fever of undetermined origin. Early identification and initiation of treatment are critical to faster recovery and prevention of progression to severe complications. Steroids remain the standard first-line therapy and should be followed by disease-modifying steroid sparing drugs. The social determinants of health may preclude their timely initiation and should alert providers of proactive ways to avoid further delays. [ABSTRACT FROM AUTHOR]

Summary For autoimmune disease (AD) and autoinflammatory disease (AID)‐related haemophagocytic lymphohistiocytosis (HLH) (AD/AID‐HLH), there is still a lack of standardized treatment. Glucocorticoids (GCs) are the main treatment currently; however, 37.9% to 61% of patients fail to achieve effective control of HLH, making it urgent to find novel treatment strategies. We conducted a retrospective, single‐centre study examining ruxolitinib (RUX)‐based regimen in children with AD/AID‐HLH. Patients were first treated with RUX monotherapy, and additional treatments including methylprednisolone and etoposide were added sequentially when the disease could not be controlled. The study included 26 patients with a median follow‐up of 23.9 months, of whom 15 had prior treatments. The overall response rate at week 8 with the RUX‐based regimen was 96.2%, with 92.3% attaining complete response (CR) and 3.9% attaining partial response. The 2‐year overall survival rate was 96.2% (95% CI, 80.4% to 99.9%). During RUX monotherapy, 46.1% of patients achieved CR as the best response, with a median first response time to RUX of 2 days. Additionally, 53.8% of patients required additional GCs and 23.1% required etoposide chemotherapy. All observed adverse events were manageable and acceptable. Overall, our study supports the efficacy and safety of the RUX‐based regimen in children with AD/AID‐HLH. [ABSTRACT FROM AUTHOR]

Background: Hepatic manifestations of hemophagocytic lymphohistiocytosis (HLH), an underrecognized primary presentation in pediatric age group, mandate high levels of suspicion for early diagnosis. Aim: This is to study the frequencies of clinical and laboratory hepatic involvement in patients with familial/primary or secondary/acquired HLH in relation to disease reactivation and outcome. Methods: A 6-month retrospective cohort study recruited 35 patients with HLH. Detailed clinical, laboratory, and genetic characteristics of HLH were collected. Hepatic transaminases and synthetic liver functions were collected at presentation, weeks 2 and 8 after starting treatment, and at time of reactivation. Biochemical liver involvement was considered when alanine aminotransferase (ALT) lived three-times more than the upper normal level. Overall (OS) and reactivation free survival were analyzed according to liver involvement. Results: Twenty patients (57%) had genetically confirmed HLH, 12 (34.3%) had MUNC13D mutations, 3 (8.5%) had STXBP2 mutations, and 5 (14.3%) had RAB27A mutations, while 9 (25.7%) had no genetic mutations with 4 of them had secondary HLH. Six patients (17.2%) patients had unknown genetics status. Median (IQR) age of the whole group was 18 months (6–36) with an age range of 2–108 months. Liver enlargement was detected at diagnosis in 29 (82.9%) and at reactivation in 18 (51.4%) patients. Eight (22.86%) patients had biochemical hepatic involvement at presentation with no significant difference in their demographic, initial clinical presentation, survival, or the type of mutant gene according to liver involvement. Conclusion: Variable hepatic biochemical involvement might be the presenting manifestation of HLH at diagnosis and upon reactivation, yet it did not impact disease outcome. [ABSTRACT FROM AUTHOR]

Hemophagocytic lymphohistiocytosis (HLH) is a life-threatening disease. Relapsed/refractory disease is the main cause of death. This study aims to determine the prognostic indicators for relapsed/refractory disease in childhood HLH (R/R HLH). Infants and children under 18 years of age who were diagnosed with HLH according to HLH-2004 criteria, MAS-HLH criteria for rheumatologic diseases, or H-score undergoing treatment in Chiang Mai University hospital between 2010 and 2022 were included. Demographic data, clinical characteristics, and laboratory parameters were retrospectively reviewed. Out of 86 childhood HLH cases, 30 patients (34.9%) experienced R/R HLH. All patients with primary HLH developed R/R HLH. The most common form of secondary HLH was infection-associated hemophagocytic syndrome (IAHS), comprising 43 cases. Of these, 37.2% had relapsed or refractory disease. Univariable analysis identified several potential risk factors for R/R HLH, including younger age, severe disease status, higher HLH-2004 criteria scores, higher H-scores, overt DIC, higher pSOFA scores, and increased levels of aspartate aminotransferase, total bilirubin, and direct bilirubin. Multivariable logistic regression analysis revealed that a pSOFA score of ≥ 8 and age < 3 years were independent risk factors for R/R HLH, with adjusted odds ratios of 6.35 (95% confidence interval [CI], 1.18–34.19; P = 0.032) and 3.62 (95% CI, 1.04–12.63; P = 0.044), respectively. Children with HLH who have a pSOFA score of ≥ 8, or are younger than 3 years, are at a higher risk of relapsed or refractory disease. Further evaluation of management strategies in this context is warranted. [ABSTRACT FROM AUTHOR]

Objective • To improve the understanding of aggressive NK-cell leukemia (ANKL) and summarize the progress of its diagnosis and treatment. Methods • We retrospectively analyzed a case of a patient who was initially diagnosed with T-cell lymphoma (non- specific type) and later transformed into ANKL through examinations such as bone marrow smear, flow cytometry, Q-mNGS, and pathology. We described the patient’s diagnostic and treatment journey and conducted a literature review. Results • The patient presented with concomitant hemophagocytic syndrome upon admission. After treatment with the HLH-94 regimen, the patient developed tumor lysis syndrome, leading to a sudden onset of ventricular tachycardia and respiratory and cardiac arrest on the third day of admission. Despite aggressive resuscitation efforts, the patient did not survive. Conclusions • ANKL is rare in the world, and the disease is aggressive, so it is necessary to diagnose early and intervene timely. Bone marrow smear, flow cytometer and Q-mNGS are helpful to identify tumors quickly and determine the direction of diagnosis and treatment. This disease is often accompanied by hemophagocytic syndrome. When the pathogenesis is not clear, it is recommended to treat it with hormone and gamma globulin first, and after clarification, chemotherapy containing L-asparaginase may be added; pay attention to supportive treatment and vigilance against oncolysis. Allogeneic hematopoietic stem cell transplantation (allo- HSCT) can be performed as soon as possible, and the application of targeted drugs may further improve the curative effect. In a word, ANKL needs more data statistics and analysis to guide clinical diagnosis and treatment. [ABSTRACT FROM AUTHOR]

Objectives: To investigate characteristics and outcomes of critically ill cancer patients with marked hyperferritinemia. Methods: A single‐center retrospective analysis comprising cancer patients with a ferritin level >10.000 μg/L treated in the intensive care unit (ICU) between 2012 and 2022 was conducted. Results: A total of 117 patients were included in the analysis. The median age was 59 years (range: 15–86 years). Females accounted for 48% of cases. 90% of patients had a hematologic malignancy. The median maximum ferritin level was 27.349 μg/L (range: 10.300–426.073 μg/L). The diagnostic criteria of septic shock were fulfilled in 51% of cases; 31% of patients had hemophagocytic lymphohistiocytosis (HLH) according to the HLH‐2004 criteria. Mechanical ventilation, renal replacement therapy and the use of vasopressors were necessary in 59%, 35% and 70% of cases, respectively. The ICU, hospital, 90‐day and 1‐year survival rates were 33.3%, 23.1%, 23.7% and 11.7%. Patients with septic shock had a worse survival than those without septic shock (p =.001); the survival of patients who fulfilled the HLH‐2004 criteria did not differ from those who did not (p =.88). Conclusion: Critically ill cancer patients with marked hyperferritinemia have poor outcomes. The present data may help to make informed decisions for this patient group. [ABSTRACT FROM AUTHOR]

Background: Macrophage activation syndrome (MAS) is an acquired form of hemo phagocytic lymphohistiocytosis (HLH) and is usually associated with infections, autoimmune, auto inflammatory syndromes and malignancies. Case details: A 14 year old girl presented with sub-acute onset of fever with lymphadenopathy, pancytopenia,high ferritin values and a falling erythrocyte sedimentation rate. She was evaluated with relevant laboratory tests that was suggestive of systemic Lupus erythematosus and associated macrophage activation syndrome She recovered with immunosuppressive therapy and other supportive care. Conclusion: There is a need for a high index of suspicion of occult MAS and MAS in patients with systemic lupus erythematosus as it may be an initial presentation. Delay in diagnosis and initiation of treatment can lead to a higher mortality. [ABSTRACT FROM AUTHOR]

The Epstein–Barr virus (EBV) is responsible for a spectrum of human diseases and demonstrates a considerable prevalence among various populations. Advances in molecular epidemiological research have enhanced our comprehension of EBV‐related pathologies. In this study, our objective was to examine the epidemiological profile and clinical features of EBV infection in Chongqing, China. We enrolled patients suspected of EBV‐related diseases who were admitted to the First Affiliated Hospital of Chongqing Medical University between May 2013 and November 2022. Inclusion criteria were based on those who underwent EBV‐specific immunofluorescence or plasma EBV‐DNA testing. Among 13 584 inpatients, the overall seropositivity rates for EBNA‐1‐IgG, EBV‐VCA‐IgM, EBV‐EA‐IgG, EBV‐EA‐IgA, EBV‐VCA‐IgA, and EBV‐DNA were 91.89%, 7.22%, 18.00%, 16.19%, 30.78%, and 18.00%, respectively. The seropositivity rate for EBNA‐1‐IgG steadily increased with age. The seropositivity rate for VCA‐IgM, an indicator of acute EBV infection, was highest in patients aged 11–20 years at 26.41%, decreasing to 2%–6% in older patients. Additionally, among 205 outpatients, the EBV‐DNA positivity rate was 14.15%. In 3670 individuals from health check‐up centers, the seropositivity rates for EBV‐EA‐IgA and EBV‐VCA‐IgA were 11.96% and 28.09%, respectively, and the EBV‐DNA positivity rate was 11.92%, all of which were lower than those in inpatients. Among the 762 EBV‐DNA positive inpatients, adults aged 31–40 years were the least affected, with a seropositivity rate of 12.00%, which increased with age. The most common diseases associated with primary EBV infection were infectious mononucleosis (IM) (35.49%), followed by EBV infection (14.15%) and pneumonia (7.19%). The most common diseases associated with EBV reactivation were pneumonia (16.80%), nasopharyngeal carcinoma (NPC) (11.02%), and autoimmune diseases (7.04%). Patients with hemophagocytic lymphohistiocytosis (HLH) had the highest viral load, significantly higher than those with NPC, pneumonia, and liver cirrhosis. This large‐scale retrospective study explores the epidemiological characteristics and disease spectrum of EBV infection across all age groups. The findings contribute to the improvement of diagnostic and management strategies for EBV infection. [ABSTRACT FROM AUTHOR]

Introduction: Therapeutic plasma exchange (TPE) is used in a wide spectrum of diseases in critically ill pediatric patients. We aim to review the indications, complications, safety, and outcomes of critically ill children who received TPE. Methods: All of the TPE procedures performed in a pediatric intensive care unit providing tertiary care during 19 years (January 2013–January 2023) were evaluated retrospectively. A total of 154 patients underwent 486 TPE sessions. Results: Median age was 6 years (2–12.5) and 35 children had a body weight of <10 kg (22.7%). Number of organ failure was 4 (2–6). Liver diseases were the most common indication for TPE (31.2%) followed by sepsis with multiorgan dysfunction syndrome (27.3%). Overall survival rate was 72.7%. The highest mortality was observed in hemophagocytic lymphohistiocytosis group. Non‐survivors had significantly higher number of organ failure (p < 0.001), higher PRISM score (p < 0.001), and higher PELOD score on admission (p < 0.001). Adverse events were observed in 68 (13.9%) sessions. Hypotension (7.8%) and hypocalcemia (5.1%) were the most frequent adverse events. Conclusion: TPE is safe for critically ill pediatric patients with experienced staff. Survival rate may vary depending on the underlying disease. Survival decreases with the increase in the number of failed organs. [ABSTRACT FROM AUTHOR]

This case report presents a 38‐year‐old male patient who, after a febrile infection, developed super‐refractory status epilepticus and multiorgan failure, and died in 2 weeks despite the best possible intensive care. Autopsy revealed findings suggestive of hemophagocytic lymphohistiocytosis (HLH). This case shows that a rare immunological cause such as HLH may cause febrile infection‐related epilepsy syndrome (FIRES), and complications of intensive care can mask the physiological and laboratory changes in HLH. Plain Language Summary: This case report presents a 38‐year‐old man who, after a febrile infection, developed intractable epileptic activity requiring intensive care treatment. During the intensive care, the patient showed signs of multiple organ damage and died in 2 weeks despite the best possible treatment. Autopsy revealed findings suggestive of hemophagocytic lymphohistiocytosis (HLH), which is a rare immune system regulation disorder leading to persistent inflammatory state and organ damages. This case shows that an immunological disorder like HLH may underlie treatment resistant fever‐related epileptic seizures. [ABSTRACT FROM AUTHOR]

Simple Summary: A severe, fatal COVID-19 disease is often associated with the occurrence of hemophagocytosis. Hemophagocytosis is particularly pronounced in the hilar lymph nodes, indicating compartmentalized human host responses to life-threatening infections. In systemic hyper-inflammation, as in severe COVID-19 disease, there are pronounced disorders of the hematological and lymphatic systems with prognostically relevant hemophagocytosis of the bone marrow. The current work aimed to address the importance of hemophagocytosis in the lymph nodes of patients with severe COVID-19 disease. From 28 patients who died of severe COVID-19 infection, samples of the vertebral bone marrow and lymph nodes from the cervical, hilar, para-aortic, mesenteric and inguinal locations were morphologically and immunohistologically (CD163, CD68, CD61, CD71, CD3, CD20, CD138) examined for the possible presence of hemophagocytosis. In the single-center study at the University Hospital Jena, a total of 191 hemophagocytes were found in the bone marrow and a total of 780 hemophagocytes in the lymph nodes in a standardized area of 21,924 mm2 per tissue sample. With 370 hemophagocytes, hilar lymph nodes were most frequently affected (370/780; 47.44%; 95%-CI: [43.94, 50.95]), followed by cervical lymph nodes (206/780; 26.41%; 95%-CI: [23.41, 29.59]), para-aortic lymph nodes (125/780; 16.03%; 95%-CI: [13.58, 18.73]) and inguinal/mesenteric lymph nodes (79/780; 10.13%; 95%-CI: [8.155, 12.4]). Based on the standard area (21,924 mm2), the difference in the number of hemophagocytes in the bone marrow and in the hilar lymph nodes was statistically significant (p < 0.05), while this did not apply to the lymph nodes from the other locations. In fatal COVID-19 disease, hemophagocytosis is particularly found in the hilar lymph nodes and is therefore a better indicator of the severity of the disease than hemophagocytosis in the bone marrow. The findings provide some evidence for the concept of compartmentalized human host responses to life-threatening infections. [ABSTRACT FROM AUTHOR]

Background/Objectives: Multisystem Inflammatory Syndrome in Children (MIS-C) is a post-infectious complication of COVID-19. MIS-C has overlapping features with other pediatric inflammatory disorders including Kawasaki Disease (KD), Macrophage Activation Syndrome (MAS), Toxic Shock Syndrome and sepsis. The exact mechanisms responsible for the clinical overlap between MIS-C and these conditions remain unclear, and biomarkers that could distinguish MIS-C from its clinical mimics are lacking. This study aimed to provide an overview of how proteomic methods, like Mass Spectrometry (MS) and affinity-based proteomics, can offer a detailed understanding of pathophysiology and aid in the diagnosis and prognosis of MIS-C. Methods: A narrative review of relevant studies published up to July 2024 was conducted. Results: We identified 15 studies and summarized their key proteomic findings. These studies investigated the serum or plasma proteome of MIS-C patients using MS, Proximity Extension, or Aptamer-based assays. The studies associated the proteomic profile of MIS-C with laboratory and clinical parameters and/or compared it with that of other diseases including acute COVID-19, KD, MAS, pediatric rheumatic diseases, sepsis and myocarditis or pericarditis following COVID-19 mRNA immunization. Depending on the method and the control group, different proteins were increased or decreased in the MIS-C group. The limitations and challenges in MIS-C proteomic research are also discussed, and future research recommendations are provided. Conclusions: Although proteomics appear to be a promising approach for understanding the pathogenesis and uncovering candidate biomarkers in MIS-C, proteomic studies are still needed to recognize and validate biomarkers that could accurately discriminate MIS-C from its clinical mimics. [ABSTRACT FROM AUTHOR]

Hemophagocytic lymphohistiocytosis (HLH) is a rare but often fatal condition characterized by a hyperinflammatory immune response leading to multiorgan failure. It is predominantly observed in the pediatric population and can be classified as familial or acquired HLH. The latter is more common in adults, often associated with malignancy, infection, or autoimmune diseases. Among acquired HLH cases, hematologic neoplasms account for the majority, with only a few isolated reports documenting solid neoplasms as the cause. Herein, we present a case of adult HLH associated with colorectal adenocarcinoma, which, to the best of our knowledge, is only the second reported case of HLH associated with this type of cancer. [ABSTRACT FROM AUTHOR]

Introduction: Hemophagocytic lymphohistiocytosis (HLH) is a rare, complicated and life threatening hyperinflammatory syndrome that maybe triggered by various infectious agents, malignancies and rheumatologic disorders. Early diagnosis and identification of the cause is essential to initiate appropriate treatment and improve the quality of life and survival of patients. The recently developed Onco-mNGS technology can be successfully used for simultaneous detection of infections and tumors. Methods: In the present study, 92 patients with clinically confirmed HLH were etiologically subtyped for infection, tumor and autoimmunity based on CNV and microbial data generated by Onco-mNGS technology, and a predictive model was developed and validated for the differential diagnosis of the underlying disease leading to secondary HLH. Furthermore, the treatment outcomes of patients with HLH triggered by EBV infection and non-EBV infection were evaluated, respectively. Results: The current study demonstrated that the novel Onco-mNGS can identify the infection and malignancy-related triggers among patients with secondary HLH. A random forest classification model based on CNV profile, infectious pathogen spectrum and blood microbial community was developed to better identify the different HLH subtypes and determine the underlying triggers. The prognosis for treatment of HLH patients is not only associated with CNV, but also with the presence of pathogens and non-pathogens in peripheral blood. Higher CNV burden along with frequent deletions on chromosome 19, higher pathogen burden and lower non-pathogenic microbes were prognosis factors that significantly related with unfavorable treatment outcomes. Discussion: Our study provided comprehensive knowledge in the triggers and prognostic predictors of patients with secondary HLH, which may help early diagnosis and appropriate targeted therapy, thus improving the survival and prognosis of the patients. [ABSTRACT FROM AUTHOR]

Background: Hemophagocytic Lymphohistiocytosis (HLH) carries a high mortality rate. Current existing risk-evaluation methodologies fall short and improved predictive methods are needed. This study aimed to forecast 30-day mortality in adult HLH patients using 11 distinct machine learning (ML) algorithms. Methods: A retrospective analysis on 431 adult HLH patients from January 2015 to September 2021 was conducted. Feature selection was executed using the least absolute shrinkage and selection operator. We employed 11 ML algorithms to create prediction models. The area under the curve (AUC), sensitivity, specificity, positive predictive value, negative predictive value, F1 score, calibration curve and decision curve analysis were used to evaluate these models. We assessed feature importance using the SHapley Additive exPlanation (SHAP) approach. Results: Seven independent predictors emerged as the most valuable features. An AUC between 0.65 and 1.00 was noted among the eleven ML algorithms. The gradient boosting decision tree (GBDT) algorithms demonstrated the most optimal performance (1.00 in the training cohort and 0.80 in the validation cohort). By employing the SHAP method, we identified the variables that contributed to the model and their correlation with 30-day mortality. The AUC of the GBDT algorithms was the highest when using the top 4 (ferritin, UREA, age and thrombin time (TT)) features, reaching 0.99 in the training cohort and 0.83 in the validation cohort. Additionally, we developed a web-based calculator to estimate the risk of 30-day mortality. Conclusions: With GBDT algorithms applied to laboratory data, accurate prediction of 30-day mortality is achievable. Integrating these algorithms into clinical practice could potentially improve 30-day outcomes. [ABSTRACT FROM AUTHOR]

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

Objective Methods Results Conclusion Rheumatologic disease–associated hemophagocytic lymphohistiocytosis (HLH), a rare, life‐threatening, systemic hyperinflammatory syndrome, occurs as a complication of underlying rheumatologic disease. Real‐world evidence is lacking on emapalumab, a fully human monoclonal antibody that neutralizes the proinflammatory cytokine interferon‐γ, approved for treating patients with primary HLH.REAL‐HLH, a retrospective medical chart review study conducted across 33 US hospitals, assessed real‐world treatment patterns and outcomes in patients with HLH treated with one or more dose of emapalumab between November 20, 2018, and October 31, 2021. Data are presented for the subset of patients with rheumatologic disease–associated HLH.Fifteen of 105 patients (14.3%) had rheumatologic disease–associated HLH. Of these, nine (60.0%) had systemic juvenile idiopathic arthritis, and one (6.7%) had adult‐onset Still disease. Median (range) age at HLH diagnosis was 5 (0.9–39) years. Most patients (9 of 15; 60.0%) initiated emapalumab in an intensive care unit. Emapalumab was most frequently initiated for treating refractory or recurrent (10 of 15; 66.7%) disease. Most patients received HLH‐related therapies before (10 of 15; 66.7%) and concurrently with (15 of 15; 100.0%) emapalumab. Emapalumab‐containing regimens stabilized or achieved physician‐determined normalization of most laboratory parameters, including absolute neutrophil count and absolute lymphocyte count (13 of 14; 92.9%), chemokine ligand 9 (9 of 11; 81.8%), and platelets and alanine transaminase (11 of 14; 78.6%), and reduced glucocorticoid dose by 80%. Overall survival and 12‐month survival probability from emapalumab initiation were 86.7%.Emapalumab‐containing regimens stabilized or normalized most key laboratory parameters, reduced glucocorticoid dose, and were associated with low disease‐related mortality, thereby demonstrating potential benefits in patients with rheumatologic disease–associated HLH. [ABSTRACT FROM AUTHOR]

Objective: Secondary hemophagocytic lymphohistiocytosis (sHLH) is an increasingly recognized complication in patients with scrub typhus, potentially contributing to substantial mortality despite appropriate antibiotic treatment. This study aims to determine the prevalence and prognosis of sHLH and identify diagnostic factors in adult patients with scrub typhus in North India. Methods: This prospective cohort study was conducted at PGIMER, Chandigarh, from August 2021 to November 2023. sHLH was defined as an HScore of 200 or above. The diagnostic performance of biomarkers such as ferritin, fibrinogen, triglycerides, and C-reactive protein was assessed through receiver operating characteristic curve analysis, evaluating area under the curve (AUC), sensitivity, and specificity. Results: Out of 150 patients (mean age 39 years, 54% female), 28 (18.7%) were diagnosed with sHLH. Those presenting with high-grade fever, seizures, high pulse rate, hepatomegaly, splenomegaly, cytopenia, and significant hepatic dysfunction were more likely to have sHLH. Ferritin demonstrated the highest diagnostic utility (AUC 0.83), compared to fibrinogen (AUC 0.72), triglyceride (AUC 0.67), and C-reactive protein (AUC 0.69). The optimal cutoff for ferritin was 2000 ng/mL, with a sensitivity of 90% and a specificity of 66%. Higher ferritin thresholds (6000 ng/mL and 10000 ng/mL) increased specificity to 88% and 95%, respectively. Patients with sHLH often presented with multi-organ failure, necessitating mechanical ventilation and vasopressor support. In-hospital mortality was significantly higher in sHLH patients than in those without (21.4% vs 6.6%, p = 0.025). Conclusion: Early detection of sHLH using the HScore and ferritin significantly influences the management of scrub typhus, underscoring the necessity for tailored therapeutic strategies to improve patient outcomes. [ABSTRACT FROM AUTHOR]

Introduction: Epstein-Barr virus (EBV) infection, with a global prevalence exceeding 95%, typically manifests in children as infectious mononucleosis. However, clinical practice frequently encounters diverse atypical presentations characterized by multisystem involvement, often resulting in an unfavorable clinical course. Our objective is to describe the clinical manifestations and results of EBV infection in a tertiary pediatric hospital in Mexico. Method: An observational, transversal, retrospective, and descriptive study that included a systematic review of medical records (2012-2022) of patients under 18 years of age with detectable EBV particles in peripheral blood. Results: The study included 26 patients with a median age of 5 years and a male predominance of 53.8%. Predominant symptoms were fever (85%) and lymphadenopathy (35%). Sixty-five percent had severe and atypical manifestations, including pneumonia and hepatic, hematologic-oncologic, and autoimmune diseases. Anemia, thrombocytopenia and leukopenia were common, with lymphocytosis in 19% of cases. The median EBV viral load was 2816 copies/mL (range: 555-355,500 copies/mL). Four deaths related to EBV infection were reported. Viral load in these cases also varied widely from 594 to 121,000 copies/mL. Supportive care was administered to 85% of patients, while others received antiviral treatment, steroids, and rituximab. Conclusion: Atypical manifestations were common, especially in children with multisystem involvement. EBV should be considered as a potential contributor to a diverse spectrum of clinical presentations, emphasizing the need for comprehensive evaluation and awareness in clinical diagnosis. [ABSTRACT FROM AUTHOR]

Introduction: Liver dysfunction is common in patients with hemophagocytic lymphohistiocytosis (HLH). However, whether the severity of liver injury is associated with the prognosis of patients with HLH remains to be determined. This study aims to assess the association of the severity of liver involvement with short-term prognosis among adult patients with HLH. Methods: A retrospective study was performed from January 2012 to December 2020, including 150 patients with newly diagnosed HLH and liver injury. Results: The majority of our cohort suffered from mild to moderate hepatic damage, presenting with Child-Turcotte-Pugh (CTP) class A (55, 36.7%) or B (74, 49.3%). The prevalence of acute liver failure (ALF) was 9.3% in our cohort. The overall 30-day mortality rate was 49.3% among the study population. HLH patients with ALF showed an extremely adverse prognosis, with a mortality rate as high as 92.9%. In a multivariate analysis, age ≥60 years (p = 0.016), blood urea nitrogen (BUN) ≥7 μmol/L (p < 0.001), and malignancy-associated HLH (p < 0.001) at the diagnosis of HLH were identified as being strongly correlated with 30-day prognosis. An excellent predictive power was found. Among the predictive scores used to assess early death of HLH patients with liver injury, the prognostic efficiency of chronic liver failure-sequential organ failure assessment (CLIF-SOFA) (AUROC: 0.936 ± 0.0211) and SOFA score (0.901 ± 0.026) were significantly better than those of the APACHE II (p < 0.001), model for end-stage liver disease score (p < 0.001) and CTP scores (p < 0.001). Conclusion: Patients with old age, elevated BUN, and malignancy had inferior survival. CLIF-SOFA and SOFA enable more accurate prediction of early death in HLH patients with liver injury than other liver-specific and general prognostic models. [ABSTRACT FROM AUTHOR]

Background: Inborn errors of immunity (IEI), formerly referred to as primary immunodeficiencies, manifest with a wide range of symptoms such as increased susceptibility to infections, immune dysregulation, and autoinflammation. Although most cases manifest in childhood, onset during the neonatal period is rare but potentially critical. Summary: In this review, we discuss the diverse clinical presentations of IEI and the specific challenges they pose to neonatologists. Rather than detailing every molecular defect, we focus on common clinical scenarios in neonates and young infants, providing practical diagnostic strategies to ensure timely and effective therapeutic interventions. Key Messages: Clinical presentations of IEI in neonates may include delayed separation of the umbilical cord, skin rashes such as eczema and erythroderma, and recurrent episodes of inflammation. We also highlight immunological emergencies that require urgent medical attention, such as hyperinflammatory activity mimicking acute neonatal liver failure, sometimes seen in hemophagocytic lymphohistiocytosis. We also discuss appropriate medical action in the case of a positive newborn screening for severe T-cell defects. Early medical intervention in such circumstances may significantly improve outcomes. [ABSTRACT FROM AUTHOR]

Introduction: Hemophagocytic lymphohistiocytosis (HLH) is a rare, life-threatening syndrome characterized by an uncontrolled hyperinflammatory reaction. HLH is classified into primary (familial) and secondary (acquired). Secondary HLH is commonly triggered by infections, with viral infections being a leading cause. Its epidemiology and clinical features in cases associated with herpes simplex virus 1 and 2 remain underexplored. This study aimed to review all previously described cases of HSV-1 or -2-triggered HLH and provide information about this syndrome's epidemiology, microbiology, clinical characteristics, treatment, and outcomes. Methods: A narrative review was performed based on a search in PubMed, the Cochrane Library, and Scopus. Studies published until 27 April 2024 providing relevant data for HLH due to HSV 1 and 2 in humans were included. Results: We identified 29 eligible studies reporting HLH due to HSV 1 and 2, involving 34 patients. Half of them were adults, and half were neonates. Fever and splenomegaly were the most common clinical findings. Most patients were diagnosed with HSV-1 (64.7%), with PCR being the primary diagnostic method. The median duration of in-hospital treatment was 21 days, with acyclovir and steroids being the mainstays of therapy. The overall mortality rate was 41.2%, and AST levels emerged as an independent predictor of mortality. Conclusions: Our findings underscore the need for heightened awareness surrounding HLH triggered by HSV 1 and 2 and the importance of prompt diagnosis and tailored treatment approaches. [ABSTRACT FROM AUTHOR]

To explore the clinical features, treatment, and prognosis of patients with lymphoma-associated hemophagocytic syndrome (LAHS) in a real-world clinical setting. We retrospectively examined LAHS patients diagnosed at our center between January 2016 and August 2023, focusing primarily on their clinical features, therapeutic approaches, overall response rate (ORR), and overall survival (OS). A combination of univariate and multivariate analyses was conducted to identify potential prognostic factors. A total of 86 patients diagnosed with LAHS were included to evaluate clinical characteristics and prognostic factors. Patients with T/NK cell lymphoma had a higher probability of developing hemophagocytic syndrome (HPS) during the clinical process than those with B cell lymphoma. The median survival time was 55 days for all patients, and 47 and 81 days for the T/NK cell LAHS and B cell LAHS cohorts, respectively (P = 0.025). Among the patients evaluated, the ORR was 42.2%. Patients starting with anti-lymphoma treatment had a better, albeit not significant, ORR than those beginning with anti-HPS treatment. In the univariate analysis, T/NK cell LAHS (P = 0.027), HPS onset at relapse (P = 0.036), higher baseline plasma EBV-DNA levels (> 4,000 copies/mL, P = 0.034), and treatments including cytokine adsorption and ruxolitinib (P < 0.001 and P = 0.017, respectively) were potentially associated with worse OS, while corticosteroid therapy benefited OS. In the multivariate analysis, T/NK cell LAHS (adjusted hazard ratio (aHR) = 2.007), cytokine adsorption therapy (aHR = 4.547), and corticosteroid therapy (aHR = 0.118) were independently associated with mortality. T/NK cell lymphoma was the main cause of LAHS and carried a worse prognosis. Whether anti-lymphoma or anti-HPS treatment should start first still requires prospective studies with larger sample sizes. The key point in controlling HPS is to block the cytokine storm promptly. Corticosteroid therapy is both effective and accessible and should be used early and in sufficient quantities. [ABSTRACT FROM AUTHOR]

Hemophagocytic Lymphohistiocytosis (HLH) is a rare disorder of immune dysregulation characterized by fever, cytopenias, and splenomegaly. Its primary form poses a therapeutic challenge due to its high fatality when left untreated. We retrospectively analyzed 28 patients who underwent related-donor allogeneic stem cell transplant for primary HLH from 2010 to 2021. Among them were 10 cases of familial HLH, 8 cases of Griscelli syndrome type 2, and 1 case each with PRF1 and STX11 mutations. All the patients underwent transplants with reduced-intensity or myeloablative conditioning and 26 of them achieved neutrophil engraftment at a median of day + 14. The donors were either fully matched (68%) or haploidentical (32%). With a median follow-up of 1 year, overall survival was 68% (n = 19) and disease-free survival was 64.4% (n = 18). OS was better in patients transplanted with a sibling donor (compared to parent donor), who achieved complete donor chimerism, and those transplanted early in the course of the disease (diagnosis to transplant duration less than 6 months). [ABSTRACT FROM AUTHOR]

To investigate the efficacy of the doxorubicin-etoposide-methylprednisolone, DEP) regimen as an effective treatment for adult Hemophagocytic Lymphohistiocytosis secondary to rheumatic disease and analyze prognosis in these patients. Fifty-eight adult patients diagnosed with Hemophagocytic Lymphohistiocytosis secondary to rheumatic disease admitted to Beijing Friendship Hospital from 1st Jan. 2018 to 31st Dec. 2022 were retrospectively included in this study. Patients were grouped according to previous treatment. Clinical data and laboratory characteristics of patients were retrospectively analyzed. The efficacy was evaluated every 2 weeks after initiating the first course of the DEP regimen and until the last inpatient or 31st Dec. 2023. 26 patients were included in Group A and 32 patients were included in Group B due to the previous treatment. After the first course of the DEP regimen, the overall response rate of all patients was 82.8%, with 13.8% in complete response and 69% in partial response. There was no significant statistical objective response rate between the two groups after the DEP regimen, except at 2-week. Serum ferritin, sCD25, ALT, AST, and DBIL concentrations were significantly lower at 2, 4 and 6-week than pre-treatment (P < 0.05). The overall mortality rate is 20.7% (12/58). Importantly, advanced age, initial level of HB and PLT, and central nervous system (CNS) involvement were independent poor risk factors affecting OS in bivariate analysis. The DEP regimen is effective for adult HLH secondary rheumatic disease with a high overall rate and accepted side effects. [ABSTRACT FROM AUTHOR]

Babesiosis, as a vector-borne infectious disease, remains relatively rare and is prone to being overlooked and misdiagnosed. Therefore, understanding the epidemiological characteristics and clinical manifestations of babesiosis is crucial for the prompt detection and treatment of the disease. We reported a 63-year-old male patient presenting with spontaneous fever and chills. Laboratory investigations revealed erythrocytopenia, reduced hemoglobin levels, and increased reticulocytes and total bilirubin. Bone marrow examination indicated vigorous cell proliferation, a decreased granulocyte to red cell ratio, and predominant erythroid cell proliferation, with a higher prevalence of intermediate and late-stage juvenile granulocyte and erythroid cells. Initial treatment focused on hemophagocytic syndrome triggered by Epstein-Barr virus infection yielded unsatisfactory results, leading to secondary multiple pulmonary infections. Metagenomic next-generation sequencing (mNGS) of sputum samples pointed to hemolytic anemia induced by Babesia infection, which was subsequently confirmed through peripheral blood smear analysis. The patient responded well to prompt administration of atovaquone and azithromycin, with symptoms resolving and laboratory parameters normalizing. Hemolytic anemia resulting from babesiosis should be distinguished from hemophagocytic syndrome caused by Epstein-Barr virus and other hematologic conditions. mNGS represents an efficient technique for Babesia detection. [ABSTRACT FROM AUTHOR]

Objective: Monitoring the disease status of Epstein-Barr virus (EBV)-related hemophagocytic lymphohistiocytosis (HLH) patients is crucial. This study aimed to investigate the different strategies and outcomes of patients with EBV-HLH and re-elevated EBV-DNA. Method: A retrospective analysis was conducted on 20 patients diagnosed with EBV-HLH. Clinical features, laboratory tests, treatments, plasma EBV-DNA levels, and outcomes were assessed. Three cases were highlighted for detailed analysis. Results: Nine of the 20 patients had a re-elevation of EBV-DNA during treatment, and 55.5 % (5/9) experienced relapses. Patients with persistently positive plasma EBV-DNA (n = 4) and those with reelevated EBV-DNA after conversion (n = 9) showed a significantly higher relapse rate compared to those with persistently negative EBV-HLH (n = 7) (p < 0.05). Among the highlighted cases, Case 1 exhibited plasma EBV-DNA re-elevation after four weeks of treatment without relapse, maintaining stability with the original treatment regimen, and eventually, his plasma EBV-DNA turned negative. In Case 2, plasma EBV-DNA was elevated again with a recurrence of HLH after L-DEP. Consequently, she underwent allogeneic hematopoietic stem cell transplantation and eventually achieved complete remission (CR) with negative plasma EBV-DNA. Case 3 experienced plasma EBV-DNA re-elevation after L-DEP but remained in CR, discontinuing chemotherapy without relapse. Conclusion: The re-elevation of plasma EBV-DNA during EBV-HLH treatment poses challenges in determining disease status and treatment strategies. Optimal management decisions require a combination of the level of elevated EBV-DNA, the intensity of hyperinflammation, and the patient’s immune function. [ABSTRACT FROM AUTHOR]

Introduction: Adult-onset Still's disease (AOSD) is a rare chronic autoinflammatory condition characterized by a spiking fever, arthritis, a rash, hepatosplenomegaly, lymphadenopathy, leucocytosis, and hyperferritinemia. It is sometimes accompanied by life-threatening complications like macrophage activation syndrome/hemophagocytic lymphohistiocytosis (MAS/HLH). Treatment options for AOSD include glucocorticoids (GCs), immunosuppressive drugs, biological medications, and Janus kinase (JAK) inhibitors. The features that differentiate MAS/HLH from AOSD are: in MAS/HLH, a different type of fever, which is persistent, a sharp decrease in the number of leukocytes and thrombocytes, a further increase in the level of transaminases and ferritin, significant hepatosplenomegaly, lymphadenopathy, symptoms of the central nervous system (CNS), disseminated intravascular coagulation (DIC) and hemophagocytosis in the bone marrow. This study aimed to evaluate the course of AOSD, which results in MAS/HLD. Patients and methods: Nine AOSD patients, four of whom developed MAS/HLH, were treated at the Rheumatology Clinic in the Central Clinical Hospital of the Ministry of Interior Affairs from 1 January 2015 to 15 March 2020 and at the Rheumatology Clinic in the National Institute of Geriatric, Rheumatology and Rehabilitation from 1 September 2021 to 1 March 2024. Medical history, clinical data, demographic data, laboratory data, imaging data, Hscore, and treatment data were collected. Results: All the patients with MAS and an Hscore above 150 recovered. Discussion: MAS/HLH requires rapid diagnosis as well as treatment with methylprednisolone pulses, cyclosporine A, and etoposide. When comparing patients who developed MAS/HLH with those who did not, possible risk factors were identified: the presence of pregnancy (two cases) and an aggressive course of AOSD. The Hscore is a useful tool for identifying patients with MAS/HLH. [ABSTRACT FROM AUTHOR]

Hemophagocytic lymphohistiocytosis (HLH) has been recognized as a rare adverse event following the coronavirus disease 2019 (COVID-19) vaccination. We report a case of neuropsychiatric symptoms and refractory HLH in a woman with systemic lupus erythematosus (SLE) after receiving her COVID-19 vaccine treated with belimumab, later found to have intravascular large B-cell lymphoma (IVLBCL) at autopsy. A 61-year-old woman with SLE was referred to our hospital because of impaired consciousness and fever. One month prior to consulting, she received her second COVID-19 vaccine dose. Afterward, her consciousness level decreased, and she developed a high fever. She tested negative for SARS-CoV-2. Neuropsychiatric SLE was suspected; therefore, glucocorticoid pulse therapy was initiated on day 1 and 8. She had thrombocytopenia, increased serum ferritin levels and hemophagocytosis. The patient was diagnosed with HLH and treated with etoposide, dexamethasone and cyclosporine. Despite treatment, the patient died on day 75; autopsy report findings suggested IVLBCL as the underlying cause of HLH. Differentiating comorbid conditions remains difficult; however, in the case of an atypical clinical presentation, other causes should be considered. Therefore, we speculate that the COVID-19 vaccination and her autoimmune condition may have expedited IVLBCL development. [ABSTRACT FROM AUTHOR]

Objectives: To describe the clinical profile and determine the factors affecting mortality of children admitted with adenovirus infection in a tertiary care centre in South India. Methods: In this observational study, respiratory specimens (nasopharyngeal swab / endotracheal aspirate) were collected from all hospitalized pediatric patients presenting with fever, cough, breathlessness, gastrointestinal symptoms, unexplained encephalopathy or multisystem involvement, between February 2023 and August 2023. Infection with adenovirus was determined by viral pathogen panel based on polymerase chain reaction (PCR) technique. Those referred from elsewhere with positive adenovirus report but nonavailability of treatment details and children with coinfections were excluded. The clinical and laboratory profile of children with adenovirus infection were collected and predictors for in-hospital mortality were determined by logistic regression analysis. Results: Out of 527 children who were screened, 130 children with a median (IQR) age of 18 (10, 48) months, had adenovirus infection. 84.5% were aged below 5 years. 62 (41.33%) children required intensive care admission. Abnormal chest radiograph, multisystem involvement and non-respiratory illness were present in 90 (69.2%), 97 (74.62%) and 26 (20%) children. Complications included acute respiratory distress syndrome (n = 8), hemophagocytic lymphohistiocytosis (n = 7), left ventricular dysfunction (n = 11), acute liver cell failure (n = 7), acute kidney injury (n = 13), and multiorgan dysfunction (n = 16). Overall mortality was 13%. Acute kidney injury, left ventricular dysfunction and pancytopenia were identified as factors that may be significantly associated with death. Conclusions: Multisystem involvement was observed in majority of children presenting with adenovirus infection. Non-respiratory presentation is seen in a fifth of children with adenovirus infection. [ABSTRACT FROM AUTHOR]

Abstract Background Subcutaneous panniculitis-like T-cell lymphoma (SPTCL) is a rare subtype of non-Hodgkin lymphoma associated with hemophagocytic lymphohistiocytosis (HLH)/HLH-like systemic illnesses and germline HAVCR2 mutations. Although previous studies suggested successful treatment of SPTCL with immunosuppressive therapy (IST) without chemotherapy, IST data in pediatric SPTCL remain scarce. To explore characteristics and therapeutic outcomes, comparing IST-based and chemotherapy-based regimens in pediatric SPTCL, in this retrospective cohort study, patients with SPTCL diagnosed at age ≤20 years during 2007-2023 were enrolled from 6 hematology/oncology centers in Thailand. HAVCR2 exon 2 sequencing was performed using DNA extracted from peripheral blood or bone marrow. Presence of HLH/HLH-like systemic illnesses, treatment outcomes, and adverse events (AEs) were reviewed and analyzed. Results Of 22 patients with SPTCL (median age at diagnosis, 11.5 years [range, 6.0-19.0]; 63.6% males), 86.4% harbored germline HAVCR2 mutation, either homozygous (77.3%) or heterozygous (9.1%) p.Y82C variant, while 68.2% developed HLH/HLH-like systemic illnesses. Overall, 36.4% received IST as first-line treatment. Durable complete remission (CR) was achieved in 71.4% and 50.0% after first-line chemotherapy and IST, respectively (P=0.45); however, chemotherapy tended to increase any AEs compared to IST (57.1% vs. 12.5%; P=0.07). The most common AEs were hypertension (27.3%), febrile neutropenia (18.2%), and fungal infection (13.6%). Among the relapsed cases, 71.4% could reach CR after subsequent-line therapy. Fatality (4.5%) only occurred in the chemotherapy group. Conclusions Pediatric SPTCL in Thailand frequently involves germline HAVCR2 mutations and/or HLH/HLH-like systemic illnesses. With comparable response and modest therapy-related toxicity, IST-based regimens may alternatively be considered as first-line treatment for pediatric SPTCL.