Elevated serum ferritin is not specific for hemophagocytic lymphohistiocytosis

Predictors of mortality, mortality rates, and clinical characteristics of adult patients with extreme hyperferritinemia

BACKGROUND

Ferritin is an iron deposition protein and a commonly ordered clinical test. While high levels may signify iron deposition, the majority are due to metabolic, inflammatory, infectious, and malignant disorders. The association between ferritin elevations < 1000 μg/L and long-term mortality is well demonstrated. The association between extreme ferritin elevations, namely ferritin levels over 10,000 μg/L, and short-term mortality, as well as predictors of mortality, has not been defined.

METHODOLOGY

A retrospective chart study was designed in an academic hospital to analyze the clinical, laboratory, and mortality characteristics of patients whose ferritin is over 10,000 μg/L. Patients from 2012 to 2023 in a large academic center's electronic medical records were analyzed. Demographics, underlying disorders, laboratory values, mortality status, and days to mortality were acquired. Multivariate logistic regression analysis was used to define predictors of mortality. The Kaplan-Meier survival curve was used to analyze survival.

RESULTS

Sixty-seven patients were identified to have ferritin levels over 10,000 μg/L. The most common underlying disorders were infectious diseases and malignancies. Predictors of mortality in the multivariate logistic regression model were also infectious disease (odds ratio (OR) = 5.35), and malignancy (OR = 6.56), as well as age (OR = 1.05). The area under the curve of the model was .86. 1-year mortality was 62%. Of the patients who died, median survival was 5 days; 30- and 90-day mortality were 80% and 92%, respectively.

DISCUSSION

Extreme hyperferritinemia is associated with high short-term mortality. Ferritin can be used as a marker of poor prognosis, particularly among patients with infection and malignancy.

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

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

Predicting Secondary Hemophagocytic Lymphohistiocytosis in Adult Patients with Scrub Typhus and Its Prognostic Significance

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.

How to cite this article

Selvam S, Tuli A, Yuvasai KP, Saini S, Erla SR, Kaur J, et al. Predicting Secondary Hemophagocytic Lymphohistiocytosis in Adult Patients with Scrub Typhus and Its Prognostic Significance. Indian J Crit Care Med 2024;28(9):823-831.

Hyperferritinemia screening to aid identification and differentiation of patients with hyperinflammatory disorders

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

Tuberculosis-Associated Hemophagocytic Lymphohistiocytosis: Diagnostic Challenges and Determinants of Outcome

Background

Tuberculosis (TB) can induce secondary hemophagocytic lymphohistiocytosis (HLH), a severe inflammatory syndrome with high mortality. We integrated all published reports of adult HIV-negative TB-associated HLH (TB-HLH) to define clinical characteristics, diagnostic strategies, and therapeutic approaches associated with improved survival.

Methods

PubMed, Embase, and Global Index Medicus were searched for eligible records. TB-HLH cases were categorized into (1) patients with a confirmed TB diagnosis receiving antituberculosis treatment while developing HLH and (2) patients presenting with HLH of unknown cause later diagnosed with TB. We used a logistic regression model to define clinical and diagnostic parameters associated with survival.

Results

We identified 115 individual cases, 45 (39.1%) from countries with low TB incidence (<10/100 000 per year). When compared with patients with HLH and known TB (n = 21), patients with HLH of unknown cause (n = 94) more often had extrapulmonary TB (66.7% vs 88.3%), while the opposite was true for pulmonary disease (91.5% vs 59.6%). Overall, Mycobacterium tuberculosis was identified in the bone marrow in 78.4% of patients for whom examination was reported (n = 74). Only 10.5% (4/38) of patients tested had a positive result upon a tuberculin skin test or interferon-γ release assay. In-hospital mortality was 28.1% (27/96) in those treated for TB and 100% (18/18) in those who did not receive antituberculosis treatment (P < .001).

Conclusions

Tuberculosis should be considered a cause of unexplained HLH. TB-HLH is likely underreported, and the diagnostic workup of patients with HLH should include bone marrow investigations for evidence of Mycobacerium tuberculosis. Prompt initiation of antituberculosis treatment likely improves survival in TB-HLH.

Colorectal Carcinoma-An Anomalous Trigger of Adult Hemophagocytic Lymphohistiocytosis

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.

Update on Fever of Unknown Origin in Children: Focus on Etiologies and Clinical Approach

Fever of unknown origin (FUO) can be caused by four etiological categories of diseases. The most common cause of FUO in children is represented by infections, followed by inflammatory conditions and neoplastic causes; a decreasing quote remains still without diagnosis. Despite the fact that several diagnostic and therapeutic approaches have been proposed since the first definition of FUO, none of them has been fully validated in pediatric populations. A focused review of the patient's history and a thorough physical examination may offer helpful hints in suggesting a likely diagnosis. The diagnostic algorithm should proceed sequentially, and invasive testing should be performed only in select cases, possibly targeted by a diagnostic suspect. Pioneering serum biomarkers have been developed and validated; however, they are still far from becoming part of routine clinical practice. Novel noninvasive imaging techniques have shown promising diagnostic accuracy; however, their positioning in the diagnostic algorithm of pediatric FUO is still not clear. This narrative review aims to provide a synopsis of the existent literature on FUO in children, with its major causes and possible diagnostic workup, to help the clinician tackle the complex spectrum of pediatric FUO in everyday clinical practice.

Improved hemophagocytic lymphohistiocytosis index predicts prognosis of adult Epstein-Barr virus-associated HLH patients

BACKGROUND

Epstein-Barr virus (EBV)-associated hemophagocytic lymphohistiocytosis (EBV-HLH) is a common subtype of HLH with heterogeneous clinical presentations from self-limited to death, of which adults are worse than children.

OBJECTIVE

To establish predictors of mortality risk in adult EBV-HLH patients for timely and appropriate treatment.

METHODS

Patients with confirmed EBV-HLH admitted to Beijing Friendship Hospital from January 2015 to December 2019 were enrolled and statistical analysis of their laboratory test results was performed.

RESULTS

Among 246 adult patients with EBV-HLH, the deceased were older (p < 0.05), with fewer blood cells (p < 0.05), poorer renal function (p < 0.01), higher levels of procalcitonin (PCT) (p < 0.01), as well as soluble interleukin-2 receptor (sCD25) (p < 0.01). The overall median survival time of patients was 135 days, 87 days for patients without transplantation and 294 days with transplantation (p < 0.001). A combined index of sCD25, PCT, and estimated glomerular filtration rate (eGFR) was obtained to predict prognosis, named the Improved HLH index (IH index), and patients were divided into three groups meeting IH- (i.e. sCD25 ≤ 18,000 pg/mL, PCT ≤ 1.8 ng/mL, eGFR ≥ 90 mL/min/1.73m²), IH1+ (i.e. only sCD25 > 18,000 pg/mL or only eGFR < 90 mL/min/1.73m²), and IH2+ (i.e. the rest), respectively. In patients with the HScore ≥ 169 or meeting HLH-04, those meeting IH2+ had significantly worse prognoses than those who met IH1+ or IH- (p < 0.001). In the group meeting IH + or IH2+, patients who received allo-HSCT had better prognoses than those who did not (p < 0.05), but there was still a significant difference in prognosis among the three groups in transplanted patients (p < 0.001).

CONCLUSION

The IH index can early identify adult patients with a poor prognosis of EBV-HLH, initiating timely and appropriate treatment.KEY MESSAGESA combined index of sCD25, PCT, and eGFR was obtained to predict prognosis, named the Improved Hemophagocytic Lymphohistiocytosis index (IH index).IH index can early identify adult patients with a poor prognosis of EBV-HLH, initiating timely and appropriate treatment.

Isolated ACTH deficiency: an uncommon cause of hyperferritinaemia

Isolated adrenocorticotropic hormone deficiency (IAD) is a rare disorder but not a known cause of hyperferritinaemia. We here report a man with IAD who presented with mild anaemia and unexpected hyperferritinaemia (serum ferritin, 1796 µg/L). He had high serum hepcidin and relatively low erythropoietin levels for his anaemia, with hepcidin and ferritin levels reducing with hydrocortisone supplementation. We speculate that low glucocorticoid levels might suppress erythropoiesis and anti-inflammatory activity, resulting in a higher hepcidin level and hyperferritinaemia. The possibility of adrenal insufficiency including IAD should be considered as a differential diagnosis in patients with unexplained hyperferritinaemia.

The 2022 EULAR/ACR Points to Consider at the Early Stages of Diagnosis and Management of Suspected Haemophagocytic Lymphohistiocytosis/Macrophage Activation Syndrome (HLH/MAS)

OBJECTIVE

Haemophagocytic lymphohistiocytosis (HLH) and macrophage activation syndrome (MAS) are life-threatening systemic hyperinflammatory syndromes that can develop in most inflammatory contexts. They can progress rapidly, and early identification and management are critical for preventing organ failure and mortality. This effort aimed to develop evidence-based and consensus-based points to consider to assist clinicians in optimising decision-making in the early stages of diagnosis, treatment and monitoring of HLH/MAS.

METHODS

A multinational, multidisciplinary task force of physician experts, including adult and paediatric rheumatologists, haematologist/oncologists, immunologists, infectious disease specialists, intensivists, allied healthcare professionals and patients/parents, formulated relevant research questions and conducted a systematic literature review (SLR). Delphi methodology, informed by SLR results and questionnaires of experts, was used to generate statements aimed at assisting early decision-making and optimising the initial care of patients with HLH/MAS.

RESULTS

The task force developed 6 overarching statements and 24 specific points to consider relevant to early recognition of HLH/MAS, diagnostic approaches, initial management and monitoring of HLH/MAS. Major themes included the simultaneous need for prompt syndrome recognition, systematic evaluation of underlying contributors, early intervention targeting both hyperinflammation and likely contributors, careful monitoring for progression/complications and expert multidisciplinary assistance.

CONCLUSION

These 2022 EULAR/American College of Rheumatology points to consider provide up-to-date guidance, based on the best available published data and expert opinion. They are meant to help guide the initial evaluation, management and monitoring of patients with HLH/MAS in order to halt disease progression and prevent life-threatening immunopathology.

The 2022 EULAR/ACR points to consider at the early stages of diagnosis and management of suspected haemophagocytic lymphohistiocytosis/macrophage activation syndrome (HLH/MAS)

OBJECTIVE

Haemophagocytic lymphohistiocytosis (HLH) and macrophage activation syndrome (MAS) are life-threatening systemic hyperinflammatory syndromes that can develop in most inflammatory contexts. They can progress rapidly, and early identification and management are critical for preventing organ failure and mortality. This effort aimed to develop evidence-based and consensus-based points to consider to assist clinicians in optimising decision-making in the early stages of diagnosis, treatment and monitoring of HLH/MAS.

METHODS

A multinational, multidisciplinary task force of physician experts, including adult and paediatric rheumatologists, haematologist/oncologists, immunologists, infectious disease specialists, intensivists, allied healthcare professionals and patients/parents, formulated relevant research questions and conducted a systematic literature review (SLR). Delphi methodology, informed by SLR results and questionnaires of experts, was used to generate statements aimed at assisting early decision-making and optimising the initial care of patients with HLH/MAS.

RESULTS

The task force developed 6 overarching statements and 24 specific points to consider relevant to early recognition of HLH/MAS, diagnostic approaches, initial management and monitoring of HLH/MAS. Major themes included the simultaneous need for prompt syndrome recognition, systematic evaluation of underlying contributors, early intervention targeting both hyperinflammation and likely contributors, careful monitoring for progression/complications and expert multidisciplinary assistance.

CONCLUSION

These 2022 EULAR/American College of Rheumatology points to consider provide up-to-date guidance, based on the best available published data and expert opinion. They are meant to help guide the initial evaluation, management and monitoring of patients with HLH/MAS in order to halt disease progression and prevent life-threatening immunopathology.

Serum sCD25/ferritin ratio combined with MCP-1 is a valid predictor for identifying LAHS with HLH as the first manifestation

PURPOSE

Lymphoma-associated haemophagocytic syndrome (LAHS) is a group of malignant diseases with rapid progression and a high mortality rate. Our study aimed to discover the significance of serum sCD25/ferritin ratio as well as cytokines in assisting the diagnosis of LAHS.

METHODS

We retrospectively analyzed the clinical data of 82 patients with LAHS with hemophagocytic lymphohistiocytosis (HLH) as the first manifestation and divided them into B-LAHS group and T/NK-LAHS group according to lymphoma pathological diagnosis for comparison. And patients with LAHS were divided into responding group, non-responding group according to the assessment of efficacy after receiving DEP/L-DEP induction therapy for 2 weeks to compare possible valuable indicators.

RESULTS

Serum sCD25/ferritin ratio and MCP-1 levels were significantly different between B-LAHS and T/NK-LAHS groups (P = 0.001, P = 0.022). An sCD25/ferritin ratio > 7.8 tended to suggest a diagnosis of B-LAHS (AUC = 0.71, 95% CI: 0.596-0.823), and the sCD25/ferritin ratio had better predictive value when combined with MCP-1 (AUC = 0.81, 95% CI: 0.699-0.922). The sCD25/ferritin ratio was also significantly different between the two groups responding or not responding to induction therapy (P = 0.002), yielding an optimal cutoff value of 11.48. An sCD25/ferritin ratio > 11.48 tended to suggest that the patient's LAHS was responsive to induction therapy.

CONCLUSION

Our study reveals that serum sCD25/ferritin ratio combined with MCP-1 is a valid predictor for identifying LAHS with HLH as the first manifestation and may assist in predicting whether the lymphoma is of B-cell or T/NK-cell origin. The sCD25/ferritin ratio can also be used to predict the early response of LAHS after induction therapy.

Pediatric Hemophagocytic Lymphohistiocytosis: Formation of an Interdisciplinary HLH Working Group at a Single Institution

Fever of unknown origin is a common presentation in children with an extensive differential diagnosis that encompasses multiple specialties. From a hematologic standpoint, the differential includes hyperinflammatory syndrome, such as hemophagocytic lymphohistiocytosis (HLH), among others. Due to the rarity of HLH and nonspecific symptoms at initial presentation, specialists are often consulted later in the disease progression, which complicates disease evaluation further. Cook Children's Medical Center (CCMC) has recently developed a multidisciplinary histiocytic disorder group that is often consulted on cases presenting with fever of unknown origin to increase awareness and potentially not miss new HLH cases. In this study, we examine the clinical presentation and workup of 13 patients consulted by the HLH work group at a single institution and describe the clinical course of 2 patients diagnosed with HLH. The goal of this project was to describe the formation of a disease-specific team and the development of a stepwise diagnostic approach to HLH. A review of the current diagnostic criteria for HLH may be warranted given findings of markers such as soluble IL2 receptor and ferritin as nonspecific and spanning multiple disciplines including rheumatology, infectious disease, and hematology/oncology.

A predictive model for identifying secondary underlying diseases of hemophagocytic lymphohistiocytosis

Background

Secondary hemophagocytic lymphohistiocytosis (HLH) is a rare, life-threatening disease of immune hyperactivation that arises in the context of infectious, inflammatory, or neoplastic triggers. The aim of this study was to establish a predictive model for the timely differential diagnosis of the original disease resulting in HLH by validating clinical and laboratory findings to further improve the efficacy of therapeutics for HLH.

Methods

We retrospectively enrolled 175 secondary HLH patients in this study, including 92 patients with hematologic disease and 83 patients with rheumatic disease. The medical records of all identified patients were retrospectively reviewed and used to generate the predictive model. We also developed an early risk score using multivariate analysis weighted points proportional to the β regression coefficient values and calculated its sensitivity and specificity for the diagnosis of the original disease resulting in HLH.

Results

The multivariate logistic analysis revealed that lower levels of hemoglobin and platelets (PLT), lower levels of ferritin, splenomegaly and Epstein-Barr virus (EBV) positivity were associated with hematologic disease, but young age and female sex were associated with rheumatic disease. The risk factors for HLH secondary to rheumatic diseases were female sex [OR 4.434 (95% CI, 1.889-10.407), P =0.001], younger age [OR 6.773 (95% CI, 2.706-16.952), P<0.001], higher PLT level [OR 6.674 (95% CI, 2.838-15.694), P<0.001], higher ferritin level [OR 5.269 (95% CI, 1.995-13.920), P =0.001], and EBV negativity [OR 27.656 (95% CI, 4.499-169.996), P<0.001]. The risk score included assessments of female sex, age, PLT count, ferritin level and EBV negativity, which can be used to predict HLH secondary to rheumatic diseases with an AUC of 0.844 (95% CI, 0.836~0.932).

Conclusion

The established predictive model was designed to help clinicians diagnose the original disease resulting in secondary HLH during routine practice, which might be improve prognosis by enabling the timely treatment of the underlying disease.

Hemophagocytic Lymphohistiocytosis Associated with Synergistic Defects of AP3B1 and ATM Genes: A Case Report and Literature Review

Hemophagocytic lymphohistiocytosis (HLH) is an overwhelming immune system activation that manifests as hyperinflammation and life-threatening multiple organ failure. However, the clinical manifestations of the systemic inflammatory response in sepsis and fulminant cytokine storm caused by HLH macrophage activation are very similar and difficult to distinguish. HLH triggered by two novel gene defects manifesting with multiorgan dysfunction syndrome (MODS) and distributive shock has not been reported. A 14-year-old male patient was hospitalized with a high fever, his condition deteriorated rapidly, accompanied by cytopenia, shock, and MODS, and he was subsequently transferred to our intensive care unit (ICU) for symptomatic and organ-supportive treatments. Laboratory indicators of cytopenia, hypofibrinogenemia, hypertriglyceridemia, hyperferritinemia, high soluble CD25, low natural killer (NK) cell cytotoxicity, and hemophagocytosis in the bone marrow confirmed the diagnosis of HLH. Molecular genetic analysis revealed that two novel heterozygous gene mutations in AP3B1 (c.3197 C > T) and ATM (c.8077 G > T) might have accounted for the onset. After treatment, the patient’s condition successfully improved. This case report demonstrates the timely determination of underlying triggers and critical care supports (supportive and etiological treatment) of HLH related to the improved outcome.

Serum ferritin is a good indicator for predicting the efficacy of adult HLH induction therapy

Background: Hemophagocytic lymphohistiocytosis (HLH) is a rare clinical syndrome with a high mortality rate. There is no biomarker to predict the early therapeutic response.Objective: Our study explores the significance of serum ferritin in predicting the response of induction therapy.Methods: We retrospectively analyzed the clinical data of 102 adult patients with HLH admitted to our hospital. These patients received HLH-94 regimen for induction therapy. The patients were divided into remission group and non-remission group according to the response of induction therapy. Results: Ferritin values between 1-4 weeks post induction were predictive of remission (p<.05), which were higher in the non-remission group than in the remission group. Ferritin obtained 2 weeks post-induction had the highest ROC for predicting remission, with a cut-off value of 1188.5 µg/L. And patients with ferritin lower than 1188.5 µg/L had better response of induction therapy.Conclusion: Our study suggests that serum ferritin is a good indicator to predict the efficacy of induction therapy for adult HLH. KEY MESSAGESSerum ferritin is a good indicator for predicting the efficacy of adult HLH induction therapy.Serum ferritin two weeks after treatment may be a better indicator to judge the early curative effect.Serum ferritin after treatment also had a predictive significance for the survival of HLH.

Extreme Hyperferritinemia: Causes and Prognosis

The significance of extreme hyperferritinemia and its association with certain diagnoses and prognoses are not well characterized. We performed a retrospective analysis of adult patients with at least one total serum ferritin (TSF) measurement ≥ 5000 µg/L over 2 years, in three university hospitals. Conditions associated with hyperferritinemia were collected, and patients were classified into 10 etiological groups. Intensive care unit (ICU) transfer and mortality rates were recorded. A total of 495 patients were identified, of which 56% had a TSF level between 5000 and 10,000 µg/L. There were multiple underlying causes in 81% of the patients. The most common causes were infections (38%), hemophagocytic lymphohistiocytosis (HLH, 18%), and acute hepatitis (14%). For TSF levels > 10,000 µg/L, there were no solid cancer or hematological malignancy without another cause of hyperferritinemia. Isolated iron-overload syndromes never exceeded TSF levels > 15,000 µg/L. Extreme hyperferritinemia (TSF levels > 25,000 µg/L) was associated with only four causes: HLH, infections, acute hepatitis and cytokine release syndromes. A total of 32% of patients were transferred to an ICU, and 28% died. Both ICU transfer rate and mortality were statistically associated with ferritin levels. An optimized threshold of 13,405 μg/L was the best predictor for the diagnosis of HLH, with a sensitivity of 76.4% and a specificity of 79.3%. Hyperferritinemia reflects a variety of conditions, but only four causes are associated with extreme hyperferritinemia, in which HLH and acute hepatitis are the most common. Extreme hyperferritinemia has a poor prognosis with increased mortality.

The first case of Streptococcus intermedius brain abscess with hemophagocytic histiocytosis

Background

Hemophagocytic lymphohistiocytosis (HLH) is a rare but potentially life-threatening immune syndrome associated with an excessive systemic inflammatory response. Viral infection caused HLH is the most common secondary HLH, but there are relatively few reports of HLH caused by bacterial infection. The present study is the first case of HLH caused by Streptococcus intermedia meningitis.

Case presentation

The patient is an 11-year-old and 9-month-old boy. The main symptoms are fever, headache, and vomiting. The imaging finding of the brain is cerebritis and brain abscess. The cerebrospinal fluid (CSF) routine test showed increased nucleated cells, but the smear and culture of CSF were negative. The metagenomics next-generation sequencing (mNGS) of CSF detected Streptococcus intermedius, and the body temperature of the children returned to normal after antibiotic treatment according to etiology. One week later, the child developed fever again, with Kawasaki disease-like manifestations. After high-dose immunoglobulin therapy, the body temperature returned to normal again. The routine blood test showed a progressive decrease in leukocytes and platelets, and bone marrow biopsy detected histiocytes phagocytosed blood cells. Then infection-associated hemophagocytic syndrome (IAHS) was diagnosed, high-dose methylprednisolone and sequential therapy were given and the patient’s recovery was encouraging.

Conclusions

Our case shows that HLH can also be secondary to Streptococcus intermediate infection, and early bone marrow biopsy is the golden standard for HLH diagnosis. mNGS can improve the detection sensitivity for pathogens when traditional pathogenic tests are negative. Conventional chemotherapy regimens may not be required for IAHS when high-dose glucocorticoids and immunoglobulin therapy are effective.

Pediatric hemophagocytic lymphohistiocytosis in a tropical country: Results of a multicenter study in Thailand

BACKGROUND

Hemophagocytic lymphohistiocytosis (HLH) is a rare, life-threatening condition caused by genetic mutation or various triggers disturbing the immune system.

METHODS

A multicenter retrospective study of pediatric patients with HLH receiving a diagnosis between January 2005 and December 2019 from three pediatric oncology centers was conducted to explore the clinical characteristics and determine prognostic factors associated with outcomes among Thai children.

RESULTS

In all, 78 patients with HLH with a median age at diagnosis of 3.17 (range, .08-17.83) years were enrolled. The male to female ratio was 1.2:1. The most common type of HLH was infection-associated hemophagocytic syndrome (IAHS) (n = 59, 75%) of which Epstein-Barr virus was the most common pathogen. Thrombocytopenia, hyperbilirubinemia, and treatment response at weeks 2 and 8 after initiating treatment were associated with mortality. Platelet count <50,000 cells/mm³ was the only independent prognostic factor to define survival outcome (p-value .035). Two-year overall survival rate was 71.3% (95% confidence interval, 59.2%-80.3%). Survival rates between IAHS, malignant associated HLH, macrophage activation syndrome, and unspecific HLH did not significantly differ (p-value .571).

CONCLUSION

IAHS was the most common cause among pediatric HLH in Thailand. The outcomes of Thai children with HLH were comparable to those of developed countries. Platelet count <50,000 cells/mm³ was the only independent prognostic factor to define survival outcome.

Therapeutic potential of induced iron depletion using iron chelators in Covid-19

Ferritin, which includes twenty-four light and heavy chains in varying proportions in different tissues, is primarily responsible for maintaining the body's iron metabolism. Its normal value is between 10 and 200 ngmL^-1 in men and between 30 and 300 ngmL^-1 in women. Iron is delivered to the tissue via them, and they act as immunomodulators, signaling molecules, and inflammatory markers. When ferritin level exceeds 1000 µgL^-1, the patient is categorized as having hyperferritinemia. Iron chelators such as deferiprone, deferirox, and deferoxamine are currently FDA approved to treat iron overload. The inflammation cascade and poor prognosis of COVID-19 may be attributed to high ferritin levels. Critically ill patients can benefit from deferasirox, an iron chelator administered orally at 20-40 mgkg^-1 once daily, as well as intravenous deferoxamine at 1000 mg initially followed by 500 mg every 4 to 12 h. It can be combined with monoclonal antibodies, antioxidants, corticosteroids, and lactoferrin to make iron chelation therapy effective for COVID-19 victims. In this article, we analyze the antiviral and antifibrotic activity of iron chelators, thereby promoting iron depletion therapy as a potentially innovative treatment strategy for COVID-19.

An improved index for diagnosis and mortality prediction in malignancy-associated hemophagocytic lymphohistiocytosis

Hemophagocytic lymphohistiocytosis (HLH) is a life-threatening inflammatory syndrome that may complicate hematologic malignancies (HMs). The appropriateness of current criteria for diagnosing HLH in the context of HMs is unknown because they were developed for children with familial HLH (HLH-2004) or derived from adult patient cohorts in which HMs were underrepresented (HScore). Moreover, many features of these criteria may directly reflect the underlying HM rather than an abnormal inflammatory state. To improve and potentially simplify HLH diagnosis in patients with HMs, we studied an international cohort of 225 adult patients with various HMs both with and without HLH and for whom HLH-2004 criteria were available. Classification and regression tree and receiver-operating curve analyses were used to identify the most useful diagnostic and prognostic parameters and to optimize laboratory cutoff values. Combined elevation of soluble CD25 (>3900 U/mL) and ferritin (>1000 ng/mL) best identified HLH-2004-defining features (sensitivity, 84%; specificity, 81%). Moreover, this combination, which we term the optimized HLH inflammatory (OHI) index, was highly predictive of mortality (hazard ratio, 4.3; 95% confidence interval, 3.0-6.2) across diverse HMs. Furthermore, the OHI index identified a large group of patients with high mortality risk who were not defined as having HLH according to HLH-2004/HScore. Finally, the OHI index shows diagnostic and prognostic value when used for routine surveillance of patients with newly diagnosed HMs as well as those with clinically suspected HLH. Thus, we conclude that the OHI index identifies patients with HM and an inflammatory state associated with a high mortality risk and warrants further prospective validation.

HLH-Like Syndrome and Rhabdomyolysis in an Adolescent Patient

Hemophagocytic lymphohistiocytosis (HLH) is a rare heterogeneous group of disorders characterized by immune overactivation. It can occur because of primary genetic mutations or secondary to almost any inflammatory or infectious process. The clinical manifestations of this syndrome are varied and life-threatening and resemble those of many malignancies, infections, sepsis, and multisystem inflammatory syndrome in children. Laboratory abnormalities often are not diagnostic for HLH until late in the disease course, and the laboratory studies are send-out tests at most institutions. Thus, quickly and accurately diagnosing pediatric patients with HLH presents significant challenges to the clinician. Furthermore, there has been recent discussion in the literature regarding the use of diagnostic criteria for HLH. In this case report, we detail an adolescent male individual who developed persistent unexplained fever, rhabdomyolysis, and regional ischemic immune myopathy. To our knowledge, there is no previous report of a pediatric patient with this rare myopathy or HLH presenting with persistent rhabdomyolysis in the literature. The patient was hospitalized for a total of 61 days, with multiple treatments attempted throughout during his course of illness. In this report, we highlight the importance of using diagnostic flexibility when HLH is suspected in pediatric patients and provide insight into the unique challenges of identifying this condition.

[Relationship between marked hyperferritinemia and hemophagocytic lymphohistiocytosis]

OBJECTIVE

To investigate the relationship between marked hyperferritinemia (MHF) and hemophagocytic lymphohistiocytosis(HLH).

METHODS

The clinical data of 123 patients with MHF admitted to Peking University People's Hospital from January 2017 to September 2018 were collected, including demographics, baseline characteristics, signs and symptoms, blood routine, blood biochemistry, coagulation function parameters, such as prothrombin time (PT), activated partial thromboplastin time (APTT), fibrinogen (Fib), d-dimer (D-D), fibrin degradation product (FDP), blood ferritin, natural killer (NK) cell activity, soluble interleukin (IL)-2 receptor and bone marrow examination. According to the diagnosis of HLH, the patients were divided into HLH group and non HLH group. The patients were divided into death group and survival group according to the 3-month follow-up results. The groups were compared and statistically analyzed.

RESULTS

In the 123 patients with MHF, the average age was (44.2±17.4) years with a male/female ratio of 1.3 ∶1. The most common causes were hematolo-gic malignancies, rheumatologic and inflammatory disorders, iron overload, and HLH. HLH was enriched as the ferritin increased, and the HLH ratios were 28.8%, 40.0%, 54.5%, 50.0%, 50.0% in ferritin value of 10 000-19 999, 20 000-29 999, 30 000-39 999, 40 000-49 999 μg/L, more than 50 000 μg/L respectively. There were 46 cases of HLH, among which 15 cases were secondary to malignancies, 14 cases secondary to rheumatologic disorders, 2 cases secondary to infection, and 15 cases with no clear precipitating cause. There were significant differences between the HLH group and non-HLH group in hepatomegaly, splenomegaly, lymphadenectasis, albumin (ALB), fibrinogen(Fib), P < 0.05, and no significant differences in age, gender, fever, disturbance of consciousness, ferritin level on presentation, maximum ferritin level, cytopenia in 2 or more cell lines, alanine aminotransferase (ALT), aspartate aminotransferase (AST), total bilirubin (TBIL), direct bilirubin (DBIL), triglyceride (TG), coagulation parameters (PT, APTT, D-D, FDP, exception of Fib), and mortality rate (P > 0.05). There were significant differences between the death group and survival group in disturbance of consciousness, platelet count, PT, TBIL, and DBIL (P < 0.05), but no significant differences in age, gender, fever, hepatomegaly, splenomegaly, lymphadenectasis, ferritin level on presentation, maximum ferritin level, neutrophils, hemoglobin, ALT, AST, ALB, TG, coagulation parameters (Fib, APTT, D-D, FDP, exception of PT) and the HLH ratio (P > 0.05).

CONCLUSION

HLH was enriched as the ferritin increased, but marked hyperferritinemia was not specific for HLH in adults.

Spontaneous Recovery of Hemophagocytic Lymphohistiocytosis Due to Primary Epstein-Barr Virus Infection in an Adult Patient

Patient: Male, 34-year-old

Final Diagnosis: Epstein-Barr virus-associated hemophagocytic lymphohistiocytosis

Symptoms: Fever • rash

Medication: —

Clinical Procedure: —

Specialty: Hematology • Immunology • Infectious Diseases

Haemophagocytic Lymphohistiocytosis with Leptospirosis: A Rare but Devastating Complication

Introduction

Secondary haemophagocytic lymphohistiocytosis (sHLH), often associated with an array of infections, malignancies, and autoimmune diseases, is rarely seen with leptospirosis, which carries a relatively poor prognosis even with modern state-of-the-art medical care. We describe a patient with leptospirosis complicated by sHLH who succumbed to illness following multiorgan dysfunction. Case Description. A 74-year-old farmer presented with high-grade, unsettling fever for a week. Muddy water exposure and suggestive symptoms prompted investigation and management in the line of leptospirosis (IV ceftriaxone was instituted, and later, MAT (microscopic agglutination test) became positive). Subsequently, he developed severe acute hypoxemia requiring mechanical ventilation and acute renal failure requiring renal replacement therapy. Bone marrow biopsy and markedly elevated serum ferritin and triglyceride levels done on day 10 (with unresolving fever, hepatosplenomegaly, and pancytopaenia) confirmed the diagnosis of HLH. The routine cultures, retroviral studies, CMV, dengue, hanta and mycoplasma antibodies, tuberculosis and COVID-19 PCR, and malaria screening were all normal. There was no improvement of hypoxemia following intravenous methylprednisolone. He died on day 15 despite escalating organ support.

Conclusion

Leptospirosis is a common zoonotic disease in the tropics with significant morbidity and mortality. In the case of severe leptospirosis, overlapping clinical features with sHLH make the diagnosis of the latter challenging. No assessment tools are available to date to predict the risk of developing sHLH in a patient having leptospirosis. Outcome following sHLH due to leptospirosis still remains majorly ominous. A high index of suspicion and low threshold for specific investigations could possibly alter the outcome following such an occurrence.

Description of the Etiologies, Clinical Characteristics, and Outcomes in Patients with Hyperferritinemia in a Colombian Tertiary Hospital

BACKGROUND

This study analyzes the clinical characteristics, outcomes, and conditions associated with hyperferritinemia (≥5000 ng/mL) in a high-complexity center in Colombia.

METHODS

This retrospective and descriptive study was performed between 2011 and 2020, at the Fundación Valle del Lili, Cali, Colombia, by reviewing medical charts from patients who had serum ferritin measurements equal to or greater than 5000 ng/mL.

RESULTS

We found 350 reports of ferritin values ≥5000 ng/mL, corresponding to 317 patients, with a median ferritin value of 8789 (6001-15 373)  ng/mL. The most frequent etiologies were infection (n = 198, 56.57%), hematologic disorders (n = 104, 29.71%), and blood transfusion (n = 98, 28.00%). These last 2 etiologies cooccurred in 37 (10.57%) cases. The main clinical signs accompanying hyperferritinemia were fever in 199 (56.86%) cases, multiorgan involvement in 125 (35.71%), and hepatomegaly in 95 (27.14%) cases. Ninety-four (29.65%) patients died in the hospital, and 11 (3.47%) died within 30 days after medical discharge, mainly due to infection (n = 51, 48.57%). Intrahospital mortality was associated with significantly higher ferritin levels (10 846, IQR: 6425-23 459) than survival (8452, IQR: 5980-13 932) (P = 0.018).

CONCLUSIONS

Hyperferritinemia is related to many underlying causes, with infection being the principal cause in our cohort, followed by hematologic disorders. Additionally, in-hospital mortality was related to higher ferritin levels.

Diagnostic value of red blood cell distribution width, platelet distribution width, and red blood cell distribution width to platelet ratio in children with hemophagocytic lymphohistiocytosis

Background

To investigate whether red blood cell distribution width (RDW), platelet distribution width (PDW), and red blood cell distribution width to platelet ratio (RPR) can serve as biomarkers to distinguish hemophagocytic lymphohistiocytosis (HLH) from sepsis in children.

Methods

This is a retrospective study, involving 71 HLH patients, 105 sepsis patients, and 88 normal controls from January 2018 to December 2019. RDW, PDW, and RPR values were obtained from peripheral blood samples before standard treatment. The clinical differential diagnostic values of RDW, PDW, and RPR were analyzed by receiver operating characteristic (ROC) curve. In addition, peripheral blood samples after treatment from HLH patients were also collected for the same analyses.

Results

RDW, PDW, and RPR levels of the HLH patients were significantly higher than those of sepsis and normal controls (p < 0.001). In ROC curve analysis of the RDW, PDW, and RPR for diagnosis of HLH, the area under the curve (AUC) could reach to 0.7799 (95% CI = 0.7113–0.8486), 0.7835 (95% CI = 0.7093–0.8577), and 0.9268 (95% CI = 0.8886–0.9649), respectively. When using the criteria of RDW >13.75, PDW >13.30, and RPR >0.08, the sensitivity was 76.06%, 67.61%, and 84.51%, while the specificity was 68.57%, 85.71%, and 87.62%, respectively. After treatment of HLH patients, PDW and RPR were significantly reduced (p < 0.001).

Conclusions

This study shows that RDW, PDW, and RPR, which can be easily and cheaply detected, are novel indicators for differential diagnosis of HLH. PDW and RPR are useful indices for monitoring the effects of treatment on HLH.

Clinical analysis and a novel risk predictive nomogram for 155 adult patients with hemophagocytic lymphohistiocytosis

Recently, more and more attention has been paid on adult hemophagocytic lymphohistiocytosis (HLH), a disease with complicated symptoms and high mortality. In order to analyze the clinical characteristics and prediction risk factors of mortality, we designed a retrospective study with 1-year follow-up and included 155 patients admitted to Tongji Hospital diagnosed as HLH. One hundred seven patients formed the training cohort for nomogram development, and 48 patients formed the validation cohort to confirm the model's performance. All patients' clinical characteristics, laboratory results, medical records, and prognosis were analyzed. Among all the 107 patients in the training cohort, 46 were male and 61 were female, with the median age of 49.0 (IQR 31.0-63.0). The 1-year mortality rate was 43.9% (47/107) and 45.8% (22/48) in the training and validation cohort, respectively. And further multivariate logistic regression analysis in the training cohort showed that male (odds ratio 5.534, 95% CI 1.507-20.318, p = 0.010), altered mental status (11.876, 1.882-74.947, p = 0.008), serum ferritin ≥ 31,381 μg/L (8.273, 1.855-36.883, p = 0.006), and IL-6 ≥ 18.59 pg/mL (19.446, 1.527-247.642, p = 0.022) were independent risk factor of mortality. A nomogram included the four prediction factors mentioned above was also tabled to help clinicians evaluate the probability of poor outcome. Area under the receiver operating characteristic curve (AUROC) analysis, calibration curves, and decision curve analysis (DCA) certify the accuracy and the clinical usefulness of the nomogram. Our research reveals that male, altered mental status, serum ferritin ≥ 31,381 µg/L, and IL-6 ≥ 18.59 pg/mL are four independent predictors for poor prognosis. Doctors should pay more attention to patients with altered mental status, high serum ferritin, and IL-6 level, who have a higher risk of death.

Hyperferritinemia-A Clinical Overview

Ferritin is one of the most frequently requested laboratory tests in primary and secondary care, and levels often deviate from reference ranges. Serving as an indirect marker for total body iron stores, low ferritin is highly specific for iron deficiency. Hyperferritinemia is, however, a non-specific finding, which is frequently overlooked in general practice. In routine medical practice, only 10% of cases are related to an iron overload, whilst the rest is seen as a result of acute phase reactions and reactive increases in ferritin due to underlying conditions. Differentiation of the presence or absence of an associated iron overload upon hyperferritinemia is essential, although often proves to be complex. In this review, we have performed a review of a selection of the literature based on the authors’ own experiences and assessments in accordance with international recommendations and guidelines. We address the biology, etiology, and epidemiology of hyperferritinemia. Finally, an algorithm for the diagnostic workup and management of hyperferritinemia is proposed, and general principles regarding the treatment of iron overload are discussed.

Diagnostic Challenges in Pediatric Hemophagocytic Lymphohistiocytosis

Hemophagocytic lymphohistiocytosis (HLH) is a syndrome of severe immune dysregulation that encompasses a broad range of underlying genetic diseases and infectious triggers. Monogenic conditions, autoimmune diseases, and infections can all drive the phenotype of HLH and associated immune hyperactivation with hypercytokinemia. A diagnosis of HLH usually requires a combination of clinical and laboratory findings; there is no single sensitive and specific diagnostic test, which often leads to “diagnostic dilemmas” and delays in treatment initiation. Ferritin levels, one of the most commonly used screening tests, were collected across a large tertiary care pediatric hospital to identify the positive predictive value for HLH. Herein, we present several cases that illustrate the clinical challenges of confirming an HLH diagnosis. Additionally, we report on the utility of establishing a formal multi-disciplinary group to aid the prompt diagnosis and treatment of patients presenting with HLH-like pathophysiologies.

Hemophagocytic Lymphohistiocytosis in the Emergency Department: Recognizing and Evaluating a Hidden Threat

Background

Hemophagocytic lymphohistiocytosis (HLH) is a life-threatening hematologic disorder resulting from an ineffective and pathologic activation of the immune response system that may mimic common emergency department presentations, including sepsis, acute liver failure, disseminated intravascular coagulation, and flu-like illnesses such as coronavirus disease 2019 (COVID-19).

Objective

This narrative review provides a summary of the disease and recommendations for the recognition and diagnostic evaluation of HLH with a focus on the emergency clinician.

Discussion

Though the condition is rare, mortality rates are high, ranging from 20% to 80% and increasing with delays in treatment. Importantly, HLH has been recognized as a severe variation of the cytokine storm associated with COVID-19. Common features include a history of infection or malignancy, fever, splenomegaly or hepatomegaly, hyperferritinemia, cytopenias, coagulopathies, abnormal liver enzymes, and hypertriglyceridemia. Using specific features of the history, physical examination, laboratory studies, and tools such as the HScore, HLH-2004/2009, and hyperferritinemia thresholds, the emergency clinician can risk-stratify patients and admit for definitive testing. Once diagnosed, disease specific treatment can be initiated.

Conclusion

This review describes the relevant pathophysiology, common presentation findings, and a framework for risk stratification in the emergency department.

Increasing ferritin predicts early death in adult hemophagocytic lymphohistiocytosis

INTRODUCTION

Hemophagocytic lymphohistiocytosis (HLH) is a rare syndrome of pathologic immune activation. Most studies on adult HLH have evaluated prognostic factors for overall survival; factors predicting early mortality have not been sufficiently investigated.

METHODS

This was a collaborative study between Henry Ford Hospital and Barnes-Jewish Hospital. We identified all adult HLH patients with at least 2 ferritin levels within 30 days from admission.

RESULTS

One-hundred twenty-four patients were identified. There were 77 males and 47 females; the median age at diagnosis was 48 years. Multivariate analysis showed that age (OR = 11.41; 95% CI:2.71-48.04; P = .001), hepatomegaly (OR = 15.68; 95% CI:3.24-75.96; P = .001), hyponatremia (OR = 5.94; 95% CI:1.76-20.1; P = .004), hypoalbuminemia (OR = 7.47; 95% CI:2.08-26.85; P = .002), and increasing ferritin levels (OR = 19.46; 95% CI:4.69-80.71; P < .001) were significant predictors of 30-day mortality. Patients with declining ferritin by more than 35% from the ferritin peak were more likely to survive the first 30 days of admission (OR = 4.33; 95% CI:1.04-18.1; P = .033). By risk stratifying our cohort, we identified changes in ferritin levels to be the most significant prognostic factor of 30-day mortality among other risk factors. Further investigating the prognostic utility of ferritin showed that increasing ferritin during the 1st week of admission (data available for 44 patients) was the only significant predictor of 30-day mortality.

CONCLUSIONS

To the best of our knowledge, this is the first study reporting changes in ferritin to be a predictor for early death in adult HLH. Changes in ferritin might be a useful indicator of adult HLH disease activity and early prognosis.

Can we truly diagnose adult secondary hemophagocytic lymphohistiocytosis (HLH)? A critical review of current paradigms

The HLH-2004 criteria were initially conceived as inclusion criteria for a clinical trial investigating therapy for (largely primary) pediatric hemophagocytic lymphohistiocytosis (HLH). These criteria have since been extrapolated to diagnose adult secondary HLH despite their questionable generalizability. It remains unclear whether these diagnostic criteria are truly applicable among adult secondary cases, and rigorous evidence for their use among such patients is lacking. This review critically examines the utility of the HLH-2004 criteria for the diagnosis of adult secondary HLH. It is framed as a reappraisal of each of the criteria's individual components, with an assessment of the relevance of, and/or evidence regarding, each. There are clear limitations to these criteria as they apply to adult secondary HLH, however they may help guide our understanding of the disease to some extent. Some new paradigms are emerging for the diagnosis of adult secondary HLH, however these too are limited by the difficulties inherent in formulating specific criteria for a very non-specific syndrome, which lacks any single gold-standard diagnostic test.

Pediatric hemophagocytic lymphohistiocytosis

Hemophagocytic lymphohistiocytosis (HLH) is a syndrome describing patients with severe systemic hyperinflammation. Characteristic features include unremitting fever, cytopenias, hepatosplenomegaly, and elevation of typical HLH biomarkers. Patients can develop hepatitis, coagulopathy, liver failure, central nervous system involvement, multiorgan failure, and other manifestations. The syndrome has a high mortality rate. More and more, it is recognized that while HLH can be appropriately used as a broad summary diagnosis, many pediatric patients actually suffer from an expanding spectrum of genetic diseases that can be complicated by the syndrome of HLH. Classic genetic diseases in which HLH is a typical and common manifestation include pathogenic changes in familial HLH genes (PRF1, UNC13D, STXBP2, and STX11), several granule/pigment abnormality genes (RAB27A, LYST, and AP3B1), X-linked lymphoproliferative disease genes (SH2D1A and XIAP), and others such as NLRC4, CDC42, and the Epstein-Barr virus susceptibility diseases. There are many other genetic diseases in which HLH is an infrequent complication of the disorder as opposed to a prominent manifestation of the disease caused directly by the genetic defect, including other primary immune deficiencies and inborn errors of metabolism. HLH can also occur in patients with underlying rheumatologic or autoinflammatory disorders and is usually designated macrophage activation syndrome in those settings. Additionally, HLH can develop in patients during infections or malignancies without a known (or as-yet-identified) genetic predisposition. This article will attempt to summarize current concepts in the pediatric HLH field as well as offer a practical diagnostic and treatment overview.

Development of a dendrimer PAMAM‑based gold biochip for rapid and sensitive detection of endogenous IFN‑γ and anti‑IFN‑γ IgG in patients with hemophagocytic lymphohistiocytosis

Hemophagocytic lymphohistiocytosis (HLH) is a rare but severe disease characterized by immune hyperactivation and cytokine storm. Given the high mortality rate of HLH, there is a need for more effective diagnostic tools and treatments. The present study developed a dendrimer‑based protein biochip for rapid, sensitive and simultaneous detection of serum interferon (IFN)‑γ and endogenous anti‑IFN‑γ antibody (Ab) in patients with HLH. A gold biochip was modified with 1, 4‑phenylene diisothiocyanate (PDITC), polyamidoamine (PAMAM) or PDITC‑activated PAMAM. The optimal immobilization concentration for Ab capture and the reaction concentration for detecting Ab on the PDITC‑activated PAMAM‑modified biochip were 6.25 and 3.12 µg/ml, respectively; the limit of detection of IFN‑γ protein was 50 pg/ml. The efficiency of the protein‑probed biochip in detecting IFN‑γ and anti‑IFN‑γ Ab in serum samples from 77 patients with HLH was evaluated; the positive rates for IFN‑γ and anti‑IFN‑γ IgG Ab were 63.6% (49/77) and 61.0% (47/77), respectively. The present results demonstrated that the PDITC‑activated PAMAM‑modified biochip might be a sensitive tool for the specific detection of IFN‑γ and anti‑IFN‑γ Ab in serum, and might have clinical applicability for the diagnosis of HLH.

Etoposide-based treatment of adult HLH is associated with high biochemical response but poor survival outcomes

Etoposide-based treatment is the standard of care for adult HLH in many centers, yet there remains a paucity of data regarding treatment outcomes. We conducted a retrospective study of 23 adults treated with etoposide-based therapy compared to 10 pediatric HLH cases at a single center. At diagnosis, the median serum ferritin was 20,071 µg/L and 937 µg/L in adults and children, respectively; median sIL-2r was 14,524 U/mL and 4,478 U/mL. Biochemical response to treatment was high, with 21/23 adults achieving >75% reduction in serum ferritin, but one year survival was only 7/21 compared to 7/10 in pediatric cases.

Hemophagocytic lymphohistiocytosis: An update on pathogenesis, diagnosis, and therapy

Hemophagocytic lymphohistiocytosis (HLH) is a rare, life-threatening state of immune hyperactivation that arises in the setting of genetic mutations and infectious, inflammatory, or neoplastic triggers. Sustained, aberrant activation of cytotoxic CD8⁺ T cells and resultant inflammatory cytokine release are core pathogenic mechanisms. Key clinical features include high persistent fever, hepatosplenomegaly, blood cytopenia, elevated aminotransferase and ferritin levels, and coagulopathy. HLH is likely under-recognized, and mortality remains high, especially in adults; thus, prompt diagnosis and treatment are essential. Familial forms of HLH are currently treated with chemotherapy as a bridge to hematopoietic stem cell transplantation. HLH occurring in rheumatic disease (macrophage activation syndrome) is treated with glucocorticoids, IL-1 blockade, or cyclosporine A. In other forms of HLH, addressing the underlying trigger is essential. There remains a pressing need for more sensitive, context-specific diagnostic tools. Safer, more effective therapies will arise with improved understanding of the cellular and molecular mechanisms of HLH.

Hemophagocytic lymphohistiocytosis in adults: collaborative analysis of 137 cases of a nationwide German registry

Purpose

Hemophagocytic lymphohistiocytosis (HLH) is a severe hyperinflammatory syndrome emerging from a deregulated immune response due to various triggers. In adults, systematic data are sparse, which is why recommendations on diagnosis and management have been adopted from pediatric guidelines. A nationwide clinical registry with associated consulting service as collaborative initiative of HLH-specialized pediatricians and hematologists was initiated to better characterize HLH in adults.

Methods

Patients with proven or suspected HLH were registered by 44 institutions. Both HLH-2004 diagnostic criteria and the HScore (www.saintantoine.aphp.fr/score/) were used to confirm HLH diagnosis. Data referring to underlying disease, treatment, outcome, clinical presentation and laboratory findings were recorded.

Results

The study included 137 patients and provides the first systematic data on adult HLH in Germany. Median age was 50 years with a wide range (17–87 years), 87 patients (63.5%) were male. Most common triggering diseases were infections in 61 patients (44.5%) and malignancies in 48 patients (35%). Virtually all patients had elevated ferritin concentrations, and 74% had peak concentrations greater than 10,000 µg/l. At time of analysis, 67 of 131 patients (51%) had died. Patients with malignancy-associated HLH had the shortest median survival (160 days), however no statistically significant difference between subgroups was observed (p = 0.077). Platelets under 20*10⁹/l and low albumin concentrations (< 20 g/l) were associated with poor overall and 30-day survival.

Conclusion

Close multidisciplinary case consultation and cooperation is mandatory when treating adult HLH patients. Early contact with reference centers is recommended, especially in relapsing or refractory disease.

Supplementary Information

The online version contains supplementary material available at 10.1007/s00432-020-03139-4.

Reevaluating the role of ferritin in the diagnosis of adult secondary hemophagocytic lymphohistiocytosis

BACKGROUND

The standard diagnostic criteria for hemophagocytic lymphohistiocytosis (HLH) include hyperferritinemia to >500 ng/mL. This ferritin threshold is based on pediatric data, and evidence for its application among adults with secondary HLH is lacking.

OBJECTIVE AND METHODS

We conducted a retrospective study assessing the relationship between extreme hyperferritinemia and adult secondary HLH at our institution. All adult inpatients seen over a 10-year period, with serum ferritin >5000 ng/mL, were included.

RESULTS

Among 1055 patients with serum ferritin >5000 ng/mL, there were 69 cases of HLH (HLH prevalence of 6.5%). Mean ferritin among HLH patients was 70 398 ng/mL (SD 122 908), median 40 019 ng/mL (IQR 16 051-68 326). The prevalence of HLH only reached 50% as serum ferritin approached 90 000 ng/mL. A variety of conditions were contributory to hyperferritinemia, most commonly bacterial sepsis (33%), hematologic malignancy (29%), renal failure (24%), and liver injury (18%). The optimal cutoff ferritin for diagnosis of HLH was 16 000 ng/mL (sensitivity 79.4%, specificity 79.2%, PPV 20.9%, and NPV 98.2%).

CONCLUSIONS

The threshold ferritin levels used in diagnostic criteria for adult secondary HLH are too low to be clinically relevant, and efforts should be undertaken to revise them upward. Similar reappraisals should be taken of the other criteria used to diagnose adult HLH.

Hemophagocytic Lymphohistiocytosis and Other Culture Negative Sepsis-Like Syndromes in the ICU

There are many sepsis-like inflammatory syndromes that may be encountered by critical care practitioners. Clinically, these syndromes may imitate sepsis and are often identified after an extensive, but unrevealing evaluation for infection. In some instances, these syndromes are anticipated complications of advanced therapies for malignancy. It is vitally important to identify these disorders and treat them with specific chemotherapeutic or immunomodulating therapies. This chapter will focus on hemophagocytic lympho-histiocytosis (HLH), a rare disorder of pathologic immune system activation that presents as a sepsis-like illness in the critically ill. While treatment of HLH with chemotherapy and immunosuppression should be guided by an expert hematologist, the diagnosis is often made by the critical care medicine practitioner. We present a case illustrating the challenges of defining this syndrome in a patient with recurrent critical illness, and review the evidence underlying diagnostic and prognostic criteria for this protean syndrome. We also review several of the more common sepsis-like inflammatory syndromes that are encountered in the critical care unit along with their specific treatments.

Hepatic sinusoidal hemophagocytosis with and without hemophagocytic lymphohistiocytosis

BACKGROUND/PURPOSE

Hemophagocytic lymphohistiocytosis (HLH) is a rare, life threatening hyperinflammatory syndrome. Sinusoidal hemophagocytosis is occasionally observed on liver biopsy in patients who do not have clinical suspicion of HLH. We aimed at comparing the clinical characteristics and outcomes of patients with signs of hemophagocytosis on liver biopsy meeting and not meeting the HLH diagnostic criteria.

METHODS

We reviewed the clinical, laboratory features and outcomes of all adult patients consecutively admitted in our center between 08/2011 and 08/2017 presenting with liver histology showing sinusoidal hemophagocytosis and of critically ill patients presenting with severe liver disease in whom hemophagocytosis was histologically confirmed. The characteristics of patients fulfilling and not fulfilling the diagnostic criteria of HLH were compared.

RESULTS

We identified 12 cases (58% male, median age 61, 75% with a chronic underlying disease) with liver histology showing sinusoidal hemophagocytosis. All had at least some of the clinical features typically associated with HLH. Six were critical ill patients. In 4 cases with insufficient laboratory and clinical criteria, liver biopsy allowed to confirm the HLH diagnosis. Six patients died, of which four met the diagnostic criteria for HLH. Two patients with chronic liver disease died despite not fulfilling the diagnostic criteria of HLH.

CONCLUSION

Hemophagocytosis on liver biopsy may contribute to confirming a diagnosis of HLH in suspected cases with indeterminate clinical and laboratory findings. Sinusoidal hemophagocytosis in patients with cirrhosis was associated with bad outcome.

CD163 as a valuable diagnostic and prognostic biomarker of sepsis-associated hemophagocytic lymphohistiocytosis in critically ill children

OBJECTIVE

To investigate CD163 as an effective biomarker for identifying and predicting the outcomes of sepsis-associated hemophagocytic lymphohistiocytosis (SAHS) in children.

METHODS

We prospectively enrolled presumed sepsis patients who had developed prolonged fever (>7 days), hepatosplenomegaly, cytopenias, and hyperferritinemia (>500 ng/mL) despite antibiotic therapy. Blood samples were collected within 24 hours after enrolment. A nested case-control study was performed. The number of patients who fulfilled the HLH-2004 criteria, 28-day mortality outcomes, and 90-day mortality outcomes were recorded.

RESULTS

Sixty-nine patients were enrolled in the study. Significant increases in the levels of ferritin and soluble CD163 (sCD163) and the percentage of CD163-positive peripheral blood mononuclear cells (mCD163) and decreases in fibrinogen levels and the percentage of natural killer cells (NK %) were observed in patients with SAHS (n = 23) compared with those of patients with sepsis (n = 46). The area under the ROC curve (AUC) for ferritin combined with sCD163 was superior to the AUC for either ferritin or sCD163 for distinguishing SAHS from sepsis. Moreover, sCD163 was a prognostic factor for 28-day mortality (0.857 [0.659-1.000]).

CONCLUSIONS

sCD163 is a valuable biomarker for the differential diagnosis of SAHS from sepsis and effectively predicts 28-day mortality in children with SAHS.

Pneumococcal Bacteremia Complicated by Hemophagocytic Lymphohistiocytosis

From pneumonia to pericarditis, from sepsis to splenic abscess, Streptococcus pneumoniae is the causative agent of a diverse array of pyogenic disease. With the introduction of vaccines and effective antibiotic treatments, the incidence of complicated streptococcal infection has declined. We report a case of S. pneumoniae bacteremia, in the setting of occult sinusitis, complicated by hemophagocytic lymphohistiocytosis (HLH), disseminated intravascular coagulation (DIC), and recurrent pneumococcal infection. Although severe streptococcal infection has been associated with immunodeficiency or splenectomy, no such predisposition was identified in our patient. We discuss the association of streptococcal infection with HLH and DIC and review occult sinusitis as a source of pneumococcal bacteremia, with the goal of enhancing the "illness scripts" of general medical practitioners to include such entities.

Current Flow Cytometric Assays for the Screening and Diagnosis of Primary HLH

Advances in flow cytometry have led to greatly improved primary immunodeficiency (PID) diagnostics. This is due to the fact that patient blood cells in suspension do not require further processing for analysis by flow cytometry, and many PIDs lead to alterations in leukocyte numbers, phenotype, and function. A large portion of current PID assays can be classified as “phenotyping” assays, where absolute numbers, frequencies, and markers are investigated using specific antibodies. Inherent drawbacks of antibody technology are the main limitation to this type of testing. On the other hand, “functional” assays measure cellular responses to certain stimuli. While these latter assays are powerful tools that can be used to detect defects in entire pathways and distinguish variants of significance, it requires samples with robust viability and also skilled processing. In this review, we concentrate on hemophagocytic lymphohistiocytosis (HLH), describing the principles and accuracies of flow cytometric assays that have been proven to assist in the screening diagnosis of primary HLH.