Hemophagocytic lymphohistiocytosis: critical reappraisal of a potentially under-recognized condition

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

BACKGROUND

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

METHODS

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

RESULTS

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

CONCLUSION

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

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

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

Secondary hemophagocytic lymphohistiocytosis in children (Review)

Hemophagocytic lymphohistiocytosis (HLH) is a rare, life-threatening condition characterized by hyperinflammation in an uncontrolled and ineffective immune response. Despite great improvement in diagnosis and treatment, it still represents a challenge in clinical management, with poor prognosis in the absence of an aggressive therapeutic approach. The present literature review focuses on secondary HLH at pediatric age, which represents a heterogeneous group in terms of etiology and therapeutic approach. It summarizes the most recent evidence on epidemiology, pathophysiology, diagnosis, treatment and prognosis, and provides a detailed description and comparison of the major subtypes of secondary HLH. Finally, it addresses the open questions with a focus on diagnosis and new treatment insights.

Tuberculosis-Associated Hemophagocytic Lymphohistiocytosis: A Review of Current Literature

Hemophagocytic lymphohistiocytosis (HLH) is a condition of immune dysregulation and hyperinflammation, leading to organ failure and death. Malignancy, autoimmune conditions, and infections, including Mycobacterium tuberculosis (TB), are all considered triggers of HLH. The aim of this study was to review all reported cases of TB-associated HLH in English literature, and to summarize the epidemiology, diagnostics, treatment, and mortality in patients with concomitant HLH and TB. A systematic review of described cases with TB-associated HLH, via a structured literature search in the medical database PubMed, is presented. Additional articles were included through cross-referencing with existing review articles. Articles were reviewed based on a predetermined set of criteria. A total of 116 patients with TB-associated HLH were identified with a male:female ratio of about 3:2. The age at presentation ranged from 12 days to 83 years. Malignancy, autoimmunity, and renal failure were the most common comorbid conditions. Most patients received both tuberculostatic and specific immunomodulating treatment, which was associated with a 66% (48/73) survival rate compared to 56% (15/27) in those receiving only tuberculostatic treatment, and 0% (0/13) in those receiving only immunomodulating treatment. The survival rate was 55% overall. The overlapping presentation between disseminated TB and HLH poses challenging diagnostics and may delay diagnosis and treatment, leading to increased mortality. TB should be considered as a potential trigger of HLH; clinicians' knowledge and awareness of this may result in the appropriate investigations needed to ensure diagnosis and proper treatment.

Immune Effector Cell-Associated Hemophagocytic Lymphohistiocytosis-Like Syndrome

T cell-mediated hyperinflammatory responses, such as cytokine release syndrome (CRS) and immune effector cell-associated neurotoxicity syndrome (ICANS), are now well-established toxicities of chimeric antigen receptor (CAR) T cell therapy. As the field of CAR T cells advances, however, there is increasing recognition that hemophagocytic lymphohistiocytosis (HLH)-like toxicities following CAR T cell infusion are occurring broadly across patient populations and CAR T cell constructs. Importantly, these HLH-like toxicities are often not as directly associated with CRS and/or its severity as initially described. This emergent toxicity, however ill-defined, is associated with life-threatening complications, creating an urgent need for improved identification and optimal management. With the goal of improving patient outcomes and formulating a framework to characterize and study this HLH-like syndrome, we established an American Society for Transplantation and Cellular Therapy panel composed of experts in primary and secondary HLH, pediatric and adult HLH, infectious disease, rheumatology and hematology, oncology, and cellular therapy. Through this effort, we provide an overview of the underlying biology of classical primary and secondary HLH, explore its relationship with similar manifestations following CAR T cell infusions, and propose the term "immune effector cell-associated HLH-like syndrome (IEC-HS)" to describe this emergent toxicity. We also delineate a framework for identifying IEC-HS and put forward a grading schema that can be used to assess severity and facilitate cross-trial comparisons. Additionally, given the critical need to optimize outcomes for patients experiencing IEC-HS, we provide insight into potential treatment approaches and strategies to optimize supportive care and delineate alternate etiologies that should be considered in a patient presenting with IEC-HS. By collectively defining IEC-HS as a hyperinflammatory toxicity, we can now embark on further study of the pathophysiology underlying this toxicity profile and make strides toward a more comprehensive assessment and treatment approach.

Scoping review on diagnostic criteria and investigative approach in sepsis of unknown origin in critically ill patients

Background

Up to 11% of critically ill patients with sepsis have an unknown source, where the pathogen and site of infection are unclear. The aim of this scoping review is to document currently reported diagnostic criteria of sepsis of unknown origin (SUO) and identify the types and breadth of existing evidence supporting diagnostic processes to identify the infection source in critically ill patients with suspected SUO.

Methods

A literature search of Embase, MEDLINE and PubMed for published studies from 1910 to August 19, 2021 addressing the topic of SUO was performed. Study type, country of origin according to World Bank classification, diagnostic criteria of sepsis of unknown origin, and investigative approaches were extracted from the studies.

Results

From an initial 722 studies, 89 unique publications fulfilled the inclusion and exclusion criteria and were included for full text review. The most common publication type was case report/series 45/89 (51%). Only 10/89 (11%) of studies provided a diagnostic criteria of SUO, but a universally accepted diagnostic criterion was not identified. The included studies discussed 30/89 (34%) history, 23/89 (26%) examination, 57/89 (64%) imaging, microbiology 39/89 (44%), and special tests 32/89 (36%) as part of the diagnostic processes in patients with SUO.

Conclusions

Universally accepted diagnostic criteria for SUO was not found. Prospective studies on investigative processes in critically ill patients managed as SUO across different healthcare settings are needed to understand the epidemiology and inform the diagnostic criteria required to diagnose SUO.

Dilemmas in the diagnosis and pathogenesis of atypical late-onset familial haemophagocytic lymphohistiocytosis

Objectives

A congenital loss of cytotoxic lymphocyte activity leads to a potentially fatal immune dysregulation, familial haemophagocytic lymphohistiocytosis. Until recently, this disease was uniformly associated with infants or very young children, but it appears now that the onset may be delayed for decades. As a result, some adults are being mis‐ or under‐diagnosed because of their ‘atypical’ symptoms that are not recognised as immunodeficiency. The clinical picture and histopathology can overlap with those of haematologic malignancy, further complicating the diagnostic thought process. The spectrum of atypical symptoms is poorly defined, and therefore, it is important to describe these cases and the attendant immunological and cellular changes associated with familial haemophagocytic lymphohistiocytosis, in order to improve diagnosis and prevent unintended consequences of symptomatic therapies.

Methods

A 45‐year‐old patient presented with suspected T‐cell lymphoma and was treated with combination chemotherapy (cyclophosphamide, doxorubicin, vincristine, prednisolone) supplemented with granulocyte‐colony stimulating factor (G‐CSF). To mobilise stem cells for autologous transplantation, the patient was then treated with high‐dose G‐CSF and rapidly developed haemophagocytic lymphohistiocytosis. Symptoms resolved temporarily with intensive immunosuppression with alemtuzumab and durably with a subsequent allograft.

Results

The patient was found to be a carrier of bi‐allelic mutations in the STXBP2 protein that is essential for cytotoxic lymphocyte function, and the initial diagnosis has been revised as familial haemophagocytic lymphohistiocytosis.

Conclusion

This case highlights the difficulty in distinguishing atypical/late‐onset familial haemophagocytic lymphohistiocytosis from a malignant process as well as a possible exacerbation of the disease with G‐CSF therapy.

Treatment and Mortality of Hemophagocytic Lymphohistiocytosis in Adult Critically Ill Patients: A Systematic Review With Pooled Analysis

OBJECTIVES

Hemophagocytic lymphohistiocytosis is a cytokine release syndrome caused by uncontrolled immune activation resulting in multiple organ failure and death. In this systematic review, we aimed to analyze triggers, various treatment modalities, and mortality in critically ill adult hemophagocytic lymphohistiocytosis patients.

DATA SOURCES

MEDLINE database (PubMed) at October 20, 2019.

STUDY SELECTION

Studies and case series of patients greater than or equal to 18 years old, of whom at least one had to be diagnosed with hemophagocytic lymphohistiocytosis and admitted to an ICU.

DATA EXTRACTION

Source data of studies and case series were summarized and analyzed on an individual basis. Multivariable logistic regression analysis was performed adjusting for age, sex, and trigger groups. Each single treatment agent was entered as a dichotomous variable to determine treatments associated with survival, regardless if given alone or in combination.

DATA SYNTHESIS

In total, 661 patients from 65 studies and case series were included. Overall mortality was 57.8%. Infections were the most frequent trigger (49.9%), followed by malignancies (28.0%), autoimmune diseases (12.1%), unknown triggers (9.4%), and drugs (0.6%). Treatment with IV immunoglobulins was associated with improved survival (odds ratio, 0.548; 95% CI, 0.337-0.891; p = 0.015), while treatment with cyclosporine was associated with increased risk of death (odds ratio, 7.571; 95% CI, 3.702-15.483; p < 0.001). Considering different trigger groups separately, same results occurred only for infection-triggered hemophagocytic lymphohistiocytosis. No information was available on disease severity and other confounding factors.

CONCLUSIONS

Mortality of hemophagocytic lymphohistiocytosis in the ICU is high. Most common triggers were infections. Results of survival analyses may be biased by treatment indication and disease severity. Future studies prospectively investigating treatment tailored to critically ill hemophagocytic lymphohistiocytosis patients are highly warranted.

A Case of Hemophagocytic Lymphohistiocytosis Associated With Mediterranean Spotted Fever in a Healthy 29-Year-Old Female

A 29-year-old female presented with fever, headache, and epigastric pain. Though her initial presentation was benign and nonspecific, she soon developed a full-blown cytokine storm with disseminated intravascular coagulation. She was diagnosed with hemophagocytosis secondary to Rickettsia conorii infection. A good outcome was achieved thanks to prompt diagnosis and proper treatment.

Clinico-laboratory profile and perforin gene mutations of pediatric hemophagocytic lymphohistiocytosis cases: a five-year single center study

Introduction

hemophagocytic lymphohistiocytosis (HLH) is an immunological disease characterized by hemophagocytosis of blood cells and proliferation of T-cells and histiocytes in the spleen and bone marrow then infiltration into body organs. Familial HLH (FHL) is a fatal disorder and determining gene mutations is a good guide for predicting the prognosis and choosing treatment options. This study aimed to illustrate the clinical, laboratory characteristics, including perforin gene mutation screening, treatment and survival outcome of pediatric HLH patients.

Methods

we conducted this cross-sectional study on pediatric patients who were diagnosed with HLH using the revised HLH-2004 criteria, from January 2014 to February 2019 at Zagazig University Children's Hospital, Egypt. We collected demographic, clinical and laboratory data and screened for the presence of mutations in perforin (PRF1) gene by polymerase chain reaction (PCR) amplification. We treated the patients according to HLH-2004 treatment protocol and documented their survival outcome.

Results

the total number of cases were 18; eight males and ten females, the age range was between three months and 12 years. Of the eight HLH-2004 diagnostic criteria, all patients met at least five criteria. We detected PRF1 gene mutation in 38.9% (7 patients) with nine previously unreported mutations. Sixteen patients (88.9%) received HLH-2004 treatment protocol and the remaining two patients died before initiation of treatment. The overall mortality was 72.2% (13 patients).

Conclusion

our results increase the awareness of clinical and laboratory characterizations of pediatric HLH patients and the prevalence of PRF1 gene mutations among those patients.

Therapeutic blockade of granulocyte macrophage colony-stimulating factor in COVID-19-associated hyperinflammation: challenges and opportunities

The COVID-19 pandemic is a global public health crisis, with considerable mortality and morbidity exerting pressure on health-care resources, including critical care. An excessive host inflammatory response in a subgroup of patients with severe COVID-19 might contribute to the development of acute respiratory distress syndrome (ARDS) and multiorgan failure. Timely therapeutic intervention with immunomodulation in patients with hyperinflammation could prevent disease progression to ARDS and obviate the need for invasive ventilation. Granulocyte macrophage colony-stimulating factor (GM-CSF) is an immunoregulatory cytokine with a pivotal role in initiation and perpetuation of inflammatory diseases. GM-CSF could link T-cell-driven acute pulmonary inflammation with an autocrine, self-amplifying cytokine loop leading to monocyte and macrophage activation. This axis has been targeted in cytokine storm syndromes and chronic inflammatory disorders. Here, we consider the scientific rationale for therapeutic targeting of GM-CSF in COVID-19-associated hyperinflammation. Since GM-CSF also has a key role in homoeostasis and host defence, we discuss potential risks associated with inhibition of GM-CSF in the context of viral infection and the challenges of doing clinical trials in this setting, highlighting in particular the need for a patient risk-stratification algorithm.

Clinical features and outcomes of patients with hemophagocytic lymphohistiocytosis at onset of systemic autoinflammatory disorder and compare with Epstein-Barr virus (EBV)-related hemophagocytic lymphohistiocytosis

Hemophagocytic lymphohistiocytosis (HLH) is a life-threatening disease. In clinical practice, we have observed that some HLH patients who have features of systemic autoinflammatory diseases (SAIDs) exhibit unique clinical manifestations and outcomes different from other HLH patients.We analyzed data from 25 HLH patients who were considered to have SAIDs; data were collected from patients of our center between January 1, 2015 and September 1, 2018.The median age of the patients was 1.75 years. In the early phase, all patients had a fever and 92% of patients had a rash; 96% of patients had high white blood cell count (WBC), C-reaction protein, and erythrocyte sedimentation rate. With progression, the above laboratory results decreased gradually. During the HLH period, we compared SAIDs-related HLH and Epstein-Barr virus (EBV)-related HLH and found that rash was more common (92%, P < .001) and splenomegaly was less common (64%, P = .023) in SAIDs-related HLH. Further, WBC, ferritin, and Interleukin-6 levels in SAIDs-related HLH patients were higher than those in EBV-related HLH patients. In contrast, hemoglobin, triglyceride, sCD25, Interleukin-10, and interferon-γ levels in SAIDs-related HLH patients were lower compared with those in EBV-related HLH patients. SAIDs-related HLH patients received a modified HLH-2004 protocol at our center. Most patients had a good prognosis.We provide a summary of the unique clinical and laboratory features, treatment protocols, and outcomes of SAIDs patients with HLH at onset. The findings indicate that these patients had a better response to corticosteroids and cyclosporin compared with EBV-related HLH patients.

Genetic Deficiency of Interferon-γ Reveals Interferon-γ-Independent Manifestations of Murine Hemophagocytic Lymphohistiocytosis

OBJECTIVE

Familial hemophagocytic lymphohistiocytosis (FHLH) is a complex cytokine storm syndrome caused by genetic abnormalities rendering CD8+ T cells and natural killer cells incapable of cytolytic killing. In murine models of FHLH, interferon-γ (IFNγ) produced by CD8+ T cells has been identified as a critical mediator of disease, and an IFNγ-blocking antibody (emapalumab) has recently been approved by the Food and Drug Administration. However, development of hemophagocytic lymphohistiocytosis (HLH)/macrophage activation syndrome (MAS) in patients who are genetically unresponsive to IFNγ questions the absolute necessity of IFNγ in driving disease. This study was undertaken to determine the necessity of IFNγ in driving HLH.

METHODS

IFNγ^-/- Prf1^-/- mice were infected with lymphocytic choriomeningitis virus (LCMV), and HLH immunopathologic features, including survival, weight loss, cytopenias, cytokine profiles, and immune cell phenotypes, were assessed. Mixed bone marrow chimeras were created to determine the immune cell-intrinsic role of IFNγ receptor signaling. CD8+ T cell depletion and interleukin-33 (IL-33)/ST2 blockade were performed using monoclonal antibodies.

RESULTS

LCMV infection of IFNγ^-/- Prf1^-/- mice resulted in severe HLH-like disease. CD8+ T cells and the IL-33/ST2 axis remained essential mediators of disease; however, IFNγ-independent HLH immunopathology correlated with a 10-15-fold increase in neutrophilia (P < 0.001) and an altered cytokine milieu dominated by IL-6, IL-1β, and granulocyte-macrophage colony-stimulating factor (GM-CSF) (P < 0.05). Furthermore, IFNγ regulated CD8+ T cell expression of GM-CSF and neutrophil survival.

CONCLUSION

IFNγ is not necessary for the development of fulminant HLH, requiring physicians to consider case-by-case treatment strategies. Use of therapies that target upstream activators of CD8+ T cells, such as IL-33/ST2 signaling, may be more universally applicable treatment options that ameliorate both IFNγ-dependent and -independent manifestations of HLH/MAS.

Clinical characteristics of liver failure with hemophagocytic lymphohistiocytosis

Liver failure with hemophagocytic lymphohistiocytosis (HLH) is a life-threatening syndrome with high mortality. The aim of this study was to decipher clinical and laboratory characteristics of hemophagocytic lymphohistiocytosis after definite diagnosis of liver failure and to provide clues for early diagnosis and treatment of HLH in patients with liver failure. Eleven patients diagnosed with liver failure and HLH were retrospectively investigated in this study. All patients presented with jaundice, persistent high-grade fever, pancytopenia, splenomegaly, evidence of hemophagocytes in the bone marrow and laboratory abnormalities indicating HLH. The average interval from the earliest diagnosis of liver failure to a definitive diagnosis of HLH was 17.27 days. Six (54.55%) patients died during follow-up. For patients with liver failure after admission and subsequently definitively diagnosed with HLH, bilirubin and INR were significantly decreased. HLH is definitely diagnosed at an intermediate or late stage when patients have already suffered from liver failure. The initial dose of glucocorticoid (methylprednisolone) was decreased to 1-1.5 mg/kg/d and gradually reduced thereafter. In conclusion, for patients with liver failure, HLH should be screened as early as possible upon persistent fever, splenomegaly and unexplained pancytopenia. For patients with liver failure and HLH, the dosage of glucocorticoid should be reduced to avoid serious side effects.

Transfusion requirements and 30-day mortality predictors for adult hemophagocytic lymphohistiocytosis

Hemophagocytic lymphohistiocytosis (HLH) is a rare clinical syndrome characterized by an uncontrolled hyper-inflammatory response. We assessed the transfusion requirements and predictors of 30-day mortality for adult HLH patients. We identified all adult patients with a diagnosis of HLH at a large academic hospital from October 2003 through February 2017. We extracted patients' clinical and laboratory data, including transfusion requirements, from their medical records. One-hundred sixteen patients were identified. Their median age was 48 years (range 18-82); 72(62%) were male. Median duration of hospital stay was 19 days (range 1-89 days). At 30 days from admission, 81(70%) patients were alive. Death was attributed to sepsis in 21 patients, lymphoma in six, bleeding in four, GVHD in one, liver failure in one, metastatic solid tumor in one, and unknown in one. Transfusion requirements at 30 days from admission were as follows: RBC, 86% of patients, median 6 units (range 1-58); platelets, 74% of patients, median 6 units (1-67); plasma, 40% of patients, median 4 units (1-56). Renal failure (OR = 4.39; P = 0.008) and hypofibrinogenemia (OR = 4.07; P = 0.009) correlated with 30-day mortality. The transfusion requirements for adult HLH patients were high. Our study indicated that renal insufficiency and hypofibrinogenemia are predictors of early death in adult HLH.

Hemofagocitinė limfohistiocitozė: literatūros apžvalga

HEMOPHAGOCYTIC LYMPHOHISTIOCYTOSIS A LITERATURE REVIEW

Hemophagocytic lymphohistiocytosis is an immune dysregulatory syndrome that is associated with alteration in the immune response activation and inhibition balance. There are two basic forms of the syndrome: primary (genetic or familial) determined by genes mutations involved in immune cell interactions, and secondary or sporadic developing as a result of an infectious process. The exact genetic background of the secondary form is still unknown. These forms are characterized by same combination of specific hyperinflammatory reactions and clinical signs and symptoms. Discrimination between primary and secondary forms is often challenging due to the rarity of the pathology, a wide spectrum of clinical signs, and limited availability of specific tests. Etiopathogenetic treatment of the primary form is an urgent allogeneic hematopoietic stem cell transplantation, otherwise a fatal outcome is inevitable. Meanwhile, the approach to the secondary form depends on the clinical manifestation and the type of the infectious trigger. To rescue the patient, a timely diagnosis is crucial for prompt administration of appropriate treatment. Treatment of hemophagocytic lymphohistiocytosis is complicated by the high incidence of treatment-related mortality and the propensity to relapse. Keywords: hemophagocytis lymphohistiocytosis, immunodeficiency, diagnostic criteria.

A consensus review on malignancy-associated hemophagocytic lymphohistiocytosis in adults

Hemophagocytic lymphohistiocytosis (HLH) is a syndrome of severe immune activation and dysregulation resulting in extreme and often life-threatening inflammation. HLH has been well recognized in pediatric populations, and most current diagnostic and therapeutic guidelines are based on pediatric HLH. Recently there has been recognition of HLH in adults, especially secondary to immune deregulation by an underlying rheumatologic, infectious, or malignant condition. This review is focused on malignancy-associated HLH (M-HLH), in which possible mechanisms of pathogenesis include severe inflammation, persistent antigen stimulation by the tumor cells, and loss of immune homeostasis because of chemotherapy, hematopoietic stem cell transplantation, or infection. Previously considered rare, M-HLH may occur in up to 1% of patients with hematologic malignancies. M-HLH is often missed or diagnosed late in most published studies, and it has been associated with a poor median survival of less than 2 months. Identification of the clinical and laboratory features specific to M-HLH in adults may allow early detection, consultation with HLH experts, and intervention. Improved management of adult M-HLH with optimal combinations of T-lympholytic and immunosuppressive agents and the incorporation of novel agents based on the pediatric experience hopefully will improve outcomes in adults with M-HLH. Cancer 2017;123:3229-40. © 2017 American Cancer Society.

[Hemophagocytic lymphohistiocytosis : A diagnostic challenge on the ICU]

BACKGROUND

Hemophagocytic lymphohistiocytosis (HLH) has well been studied as a genetic disorder in children (primary HLH). Mutations in the regulatory complex of the cellular immune synapse lead to a loss of function of cytotoxic T‑cells and natural killer cells with excessive inflammation based on a cytokine storm. During the last decade, an increasing number of adult HLH patients without a family history of HLH (secondary or acquired HLH) have been reported. Various triggers - infections, malignancies or autoimmune diseases - result in an acquired loss of function of these cells and a sepsis-like disease. Missed or late diagnosis is believed to be a major cause of the high mortality.

OBJECTIVES

To describe the current knowledge on HLH and to raise awareness.

MATERIALS AND METHODS

Analysis of case reports, current studies, and expert recommendations.

RESULTS

Increased vigilance in identifying the adult form of HLH resulted in an increasing number of case reports over the past few years. HLH patients typically present with a clinical phenotype resembling severe sepsis or septic shock with fever, cytopenia, and organomegaly, which do not or insufficiently respond to anti-infective treatment. Early recognition of HLH distinction from sepsis, and prompt initiation of treatment - which is fundamentally different from sepsis - are crucial for improved outcome. A promising diagnostic parameter is ferritin, which has gained sufficient specificity, but only in the context of the triad of fever, cytopenia, and organomegaly. Treatment of adult HLH patients requires immunosuppression, with strict therapeutic guidance derived from the triggering disease.

CONCLUSIONS

Because of the similar clinical presentation to that of sepsis, HLH is often not recognized, resulting in a fatal outcome. In "sepsis" patients on the ICU with deterioration despite a standard of care, HLH needs to be considered by testing for ferritin when considering differential diagnoses. The complexity of the illness requires interdisciplinary patient care with specific integration of the hematologist in the diagnostic workup and therapeutic management, because of the frequent use of chemotherapy-based immunosuppression.

Malignancy-associated hemophagocytic lymphohistiocytosis in adults: Relation to hemophagocytosis, characteristics, and outcomes

BACKGROUND

Malignancy-associated hemophagocytic lymphohistiocytosis (HLH) in adults is a highly lethal disorder. Knowledge gaps have resulted in under diagnosis or delayed diagnosis.

METHODS

The University of Texas MD Anderson Cancer Center pathology database (1991-2014) was retrospectively interrogated for the keywords "hemophagocytosis" and/or "lymphohistiocytosis." Seventy-seven adult patients were identified. All had an underlying malignancy. Sixteen patients who had insufficient documentation were excluded.

RESULTS

The majority of patients who had pathologic evidence of hemophagocytosis/lymphohistiocytosis had an incomplete workup to confirm or refute HLH using the 2004 HLH criteria (HLH-2004; n = 8 variables), which is a common problem in adult HLH. Only 13 of 61 patients (21%) met the HLH-2004 diagnostic criteria based on available retrospective data. To identify potentially missed cases of HLH, the published literature was reviewed, and selected additional variables known to be associated with adult HLH were selected, resulting in extended diagnostic criteria of 18 variables. Thirty-five patients met the extended criteria, and 33 had follow-up data available. The median overall survival of the 13 patients who met both the extended criteria and the HLH-2004 criteria was similar to that of the 20 patients who met the extended criteria but NOT the HLH-2004 criteria (1.43 vs 1.76 months, respectively; P = .34) indicating a similar underlying, aggressive, systemic process. Twenty-six patients did not meet either criteria, and 17 had follow-up data available. The median overall survival of the 17 patients who had pathologic hemophagocytosis or lymphohistiocytosis but met neither criteria was significantly superior to the survival of those who met both the extended criteria and the HLH-2004 criteria and those who met the extended criteria but not the HLH-2004 criteria (17.27 vs 1.43 vs 1.76, respectively; P = .002).

CONCLUSIONS

The addition of diagnostic laboratory variables that are more easily and rapidly available in smaller institutions and primary care settings than the HLH-2004 variables may be a good surrogate to raise early suspicion of malignancy-associated HLH. Prospective validation is warranted. Cancer 2016. © 2016 American Cancer Society. Cancer 2016;122:2857-2866. © 2016 American Cancer Society.