Hemophagocytic lymphohistiocytosis: advances in pathophysiology, diagnosis, and treatment

Eculizumab in a child with atypical haemolytic uraemic syndrome and haemophagocytic lymphohistiocytosis triggered by cytomegalovirus infection

We present the case of a 21-month-old girl with two rare and life-threatening conditions, atypical haemolytic uraemic syndrome (aHUS) and haemophagocytic lymphohistiocytosis (HLH), triggered by a cytomegalovirus (CMV) infection. Soon after admission, the girl became anuric and required continuous venovenous haemodiafiltration.

Initial treatments included methylprednisolone, fibrinogen and plasma infusion (for HLH), plasmapheresis (for thrombotic microangiopathy), immunoglobulins (for inflammation), ganciclovir (for CMV infection) and the antibiotic cefotaxime. On day 5, eculizumab (600 mg) was given for aHUS, with rapid improvement in haematological and nephrological parameters. Despite a subsequent isolated episode of right heart thrombosis that resolved with heparin treatment, the patient showed a favourable response to eculizumab (300 mg/15 days), with improved renal function, normal haematological values, and no treatment complications. In conclusion, eculizumab effectively treated aHUS in this case despite a comorbid immunological disease.

Germline heterozygous variants in genes associated with familial hemophagocytic lymphohistiocytosis as a cause of increased bleeding

Familial hemophagocytic lymphohistiocytosis (FHL) is caused by biallelic variants in genes regulating granule secretion in cytotoxic lymphocytes. In FHL3-5, the affected genes UNC13D, STX11 and STXBP2 have further been shown to regulate the secretion of platelet granules, giving rise to compromised platelet function. Therefore, we aimed to investigate platelet degranulation in patients heterozygous for variants in UNC13D, STX11 and STXBP2. During the work-up of patients referred to the Coagulation Unit, Skåne University Hospital, Malmö, Sweden and the Department of Hematology, Rigshospitalet, Copenhagen, Denmark due to bleeding tendencies, 12 patients harboring heterozygous variants in UNC13D, STX11 or STXBP2 were identified using targeted whole exome sequencing. Transmission electron microscopy (TEM) was used to assess the secretion of platelet dense granules following thrombin stimulation. Platelet degranulation, activation and aggregation were further assessed by flow cytometry (FC) and light transmission aggregometry (LTA) with lumi-aggregometry. In total, eight out of twelve (67%) patients showed impaired degranulation by at least one of the assays (TEM, FC and LTA). In the 12 patients, eight different heterozygous variants were identified. One variant was strongly associated with impaired degranulation, while four of the variants were associated with impaired granule secretion to a slightly lesser extent. One additional variant was found in six out of the twelve patients, and was associated with varying degrees of degranulation impairment. Accordingly, six out of the eight (75%) identified variants were associated with impaired platelet degranulation. Our results suggest that heterozygous variants in UNC13D, STX11 and STXBP2 are sufficient to cause platelet secretion defects resulting in increased bleeding.

Clinical presentation and outcome of pediatric patients with hemophagocytic lymphohistiocytosis in China: A retrospective multicenter study

BACKGROUND

Hemophagocytic lymphohistiocytosis (HLH) is a heterogeneous disease with major diagnostic and therapeutic difficulties. A large-scale multicenter study of pediatric HLH is still lacking in China.

PROCEDURE

The Histiocytosis Study Group of the Chinese Pediatric Society conducted this retrospective study in 2014. A total of 323 patients diagnosed with HLH between 2011 and 2013 from 12 hospitals were registered.

RESULTS

The median age at diagnosis was 2.2 years (range, 0-14.6 years), with a peak age of HLH onset at 0 to 3 years (63%). Mutations in HLH-related genes were found in 27.9% (24/86) patients who underwent genetic testing. PRF1, UNC13D, STXBP2 and LYST were the predominant genes involved. Sixteen patients (66.7%) presented with only monoallelic mutations in one gene. Epstein-Barr virus (EBV) infection was the major condition related to HLH, which was documented in 74.4% (201/270) of the patients who underwent EBV detection. Of 252 evaluable patients, 64.7% (163) achieved non-active disease at the eighth week and patients treated with a protocol containing etoposide presented higher remission rates (75.6% vs. 46.8%, P < 0.001). In multivariate analysis, a younger age at diagnosis (<12 months), platelet count less than 80×10⁹ /L, central nervous system involvement, and initial treatment using a protocol without etoposide (not HLH-94/04) were independent prognostic factors indicating resistant disease.

DISCUSSION

This study first multicenter assessment of HLH in China shows some different features in Chinese children with HLH compared with those in western countries, including older age, vulnerability to EBV infection, and a high proportion of patients with single monoallelic genetic mutations.

Cytomegalovirus-Induced Hemophagocytic Lymphohistiocytosis in an Extreme Preterm Infant: Recognition and Therapy Leading to Recovery

BACKGROUND

Hemophagocytic lymphohistiocytosis (HLH) is a rare disease that can be triggered by cytomegalovirus, a relatively common infectious exposure to neonates. The clinical presentation is common to many acute illnesses seen in extreme premature infants; however, there are key clinical and laboratory findings that can lead to the diagnosis.

PURPOSE

We present a case of an extreme premature infant of 25 weeks' gestation who developed cytomegalovirus-induced HLH. Using the current published protocols that are used in pediatric cancer can be adapted for use in a premature infant, which led to remission of HLH and eventual discharge from the neonatal intensive care unit.

IMPLICATIONS FOR PRACTICE

There are published treatment protocols used in pediatric oncology that when initiated early can lead to favorable outcomes and remission in even the most fragile neonates.

IMPLICATIONS FOR RESEARCH

Additional studies are needed on the pharmacokinetics, dosing, and side effects on medications used for treatment of HLH in preterm infants. Additional research is needed to improve the clinician's ability to reach the diagnosis as well as define treatment strategies that provide optimal outcomes.

Exome sequencing for simultaneous mutation screening in children with hemophagocytic lymphohistiocytosis

In the present study, we used exome sequencing to analyze PRF1, UNC13D, STX11, and STXBP2, as well as genes associated with primary immunodeficiency disease (RAB27A, LYST, AP3B1, SH2D1A, ITK, CD27, XIAP, and MAGT1) in Thai children with hemophagocytic lymphohistiocytosis (HLH). We performed mutation analysis of HLH-associated genes in 25 Thai children using an exome sequencing method. Genetic variations found within these target genes were compared to exome sequencing data from 133 healthy individuals. Variants identified with minor allele frequencies <5% and novel mutations were confirmed using Sanger sequencing. Exome sequencing data revealed 101 non-synonymous single nucleotide polymorphisms (SNPs) in all subjects. These SNPs were classified as pathogenic (n = 1), likely pathogenic (n = 16), variant of unknown significance (n = 12), or benign variant (n = 72). Homozygous, compound heterozygous, and double-gene heterozygous variants, involving mutations in PRF1 (n = 3), UNC13D (n = 2), STXBP2 (n = 3), LYST (n = 3), XIAP (n = 2), AP3B1 (n = 1), RAB27A (n = 1), and MAGT1 (n = 1), were demonstrated in 12 patients. Novel mutations were found in most patients in this study. In conclusion, exome sequencing demonstrated the ability to identify rare genetic variants in HLH patients. This method is useful in the detection of mutations in multi-gene associated diseases.

Clinically Mild Encephalitis/Encephalopathy With a Reversible Splenial Lesion Accompanied by Epstein-Barr Virus Hemophagocytic Lymphohistiocytosis: A Case Report and Review of the Literature

Central nervous system involvement in hemophagocytic lymphohistiocytosis (HLH) is associated with a poor outcome. For such patients, it is unknown whether more aggressive therapies, such as intrathecal methotrexate or hydrocortisone, are inevitably required. We present a very rare case of 3-year-old Japanese girl who developed mild encephalitis/encephalopathy with a reversible splenial lesion, accompanied by Epstein-Barr virus-associated HLH, and review previous similar reports. Our case and previous reports suggest that mild encephalitis/encephalopathy with a reversible splenial lesion accompanied by Epstein-Barr virus-associated HLH has a relatively good prognosis, even in the absence of intrathecal treatments.

Diagnosing haemophagocytic syndrome

Haemophagocytic syndrome, or haemophagocytic lymphohistiocytosis (HLH), is a hyperinflammatory disorder characterised by uncontrolled activation of the immune system. It can result from mutations in multiple genes involved in cytotoxicity or occur secondary to a range of infections, malignancies or autoimmune rheumatic diseases. In the latter case, it is also known as macrophage activation syndrome (MAS). Characteristic features are persistent fever, hepatosplenomegaly, petechial/purpuric rash, progressive cytopenias, coagulopathy, transaminitis, raised C reactive protein, falling erythrocyte sedimentation rate, hypertriglyceridaemia, hypofibrinogenaemia and extreme hyperferritinaemia often associated with multi-organ impairment. Distinguishing HLH from systemic sepsis can present a major challenge. Criteria for diagnosis and classification of HLH and MAS are available and a serum ferritin >10 000 µg/L is strongly supportive of HLH. Without early recognition and appropriate treatment, HLH is almost universally fatal. However, with prompt referral and advancements in treatment over the past two decades, outcomes have greatly improved.

Predominant Neurologic Manifestations Seen in a Patient With a Biallelic Perforin1 Mutation (PRF1; p.R225W)

Neurological manifestations in familial hemophagocytic lymphohistiocytosis (FHL) are common, seen in up to 73% of patients in their course of disease. However, in majority of the cases central nervous system manifestations are associated with other clinical and laboratory parameters of hemophagocytic lymphohistiocytosis. We report here a case with FHL2 in whom hemophagocytic lymphohistiocytosis was a presenting manifestation which responded to specific therapy, however, there was isolated central nervous system relapse while patient was in remission and off therapy. FHL2 was confirmed on the basis of reduced perforin expression and homozygous mutation in PRF1at codon 637 in exon 3 (c.673C>T p.Arg225Trp).

A clinical study of 21 patients with hemophagocytic syndrome in 295 cases diagnosed with nasal type, extranodal nature killer/T cell lymphoma

Nasal type, extranodal nature killer (NK)/T cell lymphoma-associated hemophagocytic syndrome (NK/T-LAHS) is a rare and fatal disorder with extremely poor prognosis. To investigate its clinical characteristics and risk factors, we retrospectively analyzed 295 patients with nasal type, extranodal nature killer/T cell lymphoma, of which 21 were diagnosed with hemophagocytic syndrome, with a cumulative incidence of 7.1%. The most frequently clinical characteristics were fever, lymphadenopathy, hepatosplenomegaly, pancytopenia, hyperferritinemia, liver dysfunction, hypertriglyceridemia, hypofibrinogenemia and evaluated lactate dehydrogenase (LDH) level. After a median follow-up of 27 months, the 2-year survival for the 295 patients was 74.6%. Significant difference for 2-year survival was found between patients with and without hemophagocytic syndrome (4.8% vs. 80.0%, P<0.001). After developing hemophagocytic syndrome, all patients survived no more than 3 months, with a median survival of 35 days. Risk factors for NK/T-LAHS were bone marrow (BM) involvement (P = 0.019; relative risk, 13.649; 95% confidence interval (CI): 1.538-121.103), hepatosplenomegaly (P = 0.003; relative risk, 9.616; 95%CI: 2.154-42.918), and elevated LDH level (>314U/L) (P = 0.038; relative risk, 6.293; 95%CI: 1.108-35.735). We conducted a risk model for all 295 patients based on the 3 adverse factors as follows: low risk (233 cases, 79.0%), no factor; intermediate risk (43 cases, 14.6%), one factor; high risk (19 cases, 6.4%), 2 or 3 factors. The probabilities for developing LAHS were 0.9% for low-, 14.0% for intermediate-, and 68.4% for high-risk group. Significant differences in the 3 risk groups were observed (P<0.001).

Usual and Unusual Manifestations of Familial Hemophagocytic Lymphohistiocytosis and Langerhans Cell Histiocytosis

Familial hemophagocytic lymphohistiocytosis (FHL) and Langerhans cell histiocytosis (LCH) are histiocytic diseases that occur most commonly in young children. Improvements in recognition and treatment have been substantial for both diseases in the past decade, although early and late morbidity continue to be major concerns. These two diagnoses behave differently, although the clinical spectra for both diseases are diverse and can lead to confusion and delays in diagnosis and treatment. This article focuses on the clinical and genetic spectrum of FHL as well as the clinical and treatment variations of LCH.

[The significance of pedigree genetic screening and rapid immunological parameters in the diagnosis of primary hemophagocytic lymphohistiocytosis]

目的

探讨家系基因筛查及快速免疫学指标检测在原发性噬血细胞综合征（HLH）诊断中的意义。

方法

通过对伴有PRF1、UNC13D及SH2D1A基因突变的4例原发性HLH患者展开家系调查，分别完成基因筛查及各项免疫学指标检测（包括NK细胞活性、CD107a检测及HLH相关缺陷蛋白表达测定），评价各项检测指标在原发性HLH诊断中的意义并探讨各项指标间的相关性。

结果

4个家系基因突变分别为PRF1基因错义突变c.T172C（p.S58P）和非框架移码突变c.1083_1094del (p.361_365del）；PRF1基因错义突变c.C1349T（p.T450M）和框架移码突变c.1090_1091delCT (p.T364fsX93）；UNC13D基因错义突变c.G2588A（p.G863D）；SH2D1A基因半合子错义突变c.32T>G (p.I11S）。先证者及家系成员分别存在不同程度的NK细胞活性降低，其中PRF1基因及SH2D1A基因突变家系HLH相关基因编码穿孔素蛋白、信号淋巴细胞活化分子相关蛋白（SAP）表达水平下降，UNC13D基因突变先证者及与其存在完全相同突变位点的家系成员细胞毒脱颗粒功能（CD107a表达）显著减低。

结论

开展家系基因筛查及快速免疫学指标检测对诊断原发性HLH具有重要意义，两者具有较好的一致性，其中快速免疫学指标检测作为一种高效的检测手段，可为原发性HLH的早期诊断提供可靠依据。

Macrophage Activation Syndrome: different mechanisms leading to a one clinical syndrome

BACKGROUND

Macrophage activation syndrome (MAS) is a severe complication of rheumatic disease in childhood, particularly in systemic Juvenile Idiopathic Arthritis (sJIA). It is characterize by an uncontrolled activation and proliferation of T lymphocytes and macrophages.

MAIN CONTENT

MAS is currently classified among the secondary or acquired forms of haemophagocytic lymphohistiocytosis (sHLH). The reason is that MAS shares clinical and laboratory features with primary genetic HLH (pHLH). In this context is conceivable that some of the pathogenic mechanisms of pHLH may be involved in other forms of HLH. Heterozygosity for mutations of genes involved in pHLH may lead to a cytotoxic defect and to a development of clinical overt disease. But other different contributors might be involved to the development of MAS such as infections or underlying inflammation. In MAS, the inflammatory status of the patient is a major contributor of the disease. Indeed, the majority of the MAS episodes occurs during active disease phases or at disease onset. In addition, recent evidence in animals and humans suggest that genetics may also play a major role in contributing to hyperinflammation and particularly to macrophages hyper-responses.

CONCLUSIONS

We hypothesize that HLH may be one unique clinical syndrome, to whose generation different mechanisms may contribute, and maintained by one final effector mechanism.

How to Treat Involvement of the Central Nervous System in Hemophagocytic Lymphohistiocytosis?

OPINION STATEMENT

Central nervous system (CNS)-hemophagocytic lymphohistiocytosis (HLH) is not a disease in itself, but it is part of a systemic immune response. The vast majority of patients with CNS-HLH also have systemic HLH and a large number of patients with primary and secondary HLH have CNS involvement. Reactivations within the CNS are frequent during the course of HLH treatment and may occur concomitant with or independent of systemic relapses. It is also important to consider primary HLH as an underlying cause of "unknown CNS inflammation" as these patients may present with only CNS disease. To initiate proper treatment, a correct diagnosis must be made. A careful review of the patient's history and a thorough neurological examination are essential. In addition to the blood tests required to make a diagnosis of HLH, a lumbar puncture with cerebrospinal fluid (CSF) analysis and magnetic resonance imaging (MRI) should always be done in all cases regardless of the presence or absence of neurological signs or symptom. Treatment options for CNS-HLH include, but are not limited to, those commonly used in systemic HLH, including corticosteroids, etoposide, cyclosporine A, alemtuzumab, and ATG. In addition, intrathecal treatment with methotrexate and corticosteroids has become a standard care and is likely to be beneficial. Therapy must be initiated without inappropriate delay to prevent late effects in HLH. An interesting novel approach is an anti-IFN-gamma antibody (NI-0501), which is currently being tested. Hematopoietic stem cell transplantation (HSCT) also represents an important CNS-HLH treatment; patients with primary HLH may benefit from immediate HSCT even if there is active disease at time of transplantation, though care should be taken to monitor CNS inflammation through HSCT and treat if needed. Since CNS-HLH is a condition leading to the most severe late effects of HLH, early expert consultation is recommended.

Hemophagocytic lymphohistiocytosis in adults: An under recognized entity

Hemophagocytic lymphohistiocytosis (HLH) is a syndrome of severe immune activation with macrophage and T-cell infiltration resulting in, multi organ damage. HLH may be primary or secondary in etiology. A high index of suspicion is essential for early diagnosis and treatment. Diagnostic criteria need to be refined and newer treatment options to be explored in order to improve survival especially in adult HLH and malignancy-associated HLH (M-HLH).

We report a case of malignancy associated HLH (M-HLH) in adult treated on one of the only FDA-approved protocols for adult HLH to highlight the diagnostic and therapeutic challenges of this disease entity.

High Level of Perforin Expression Is Required for Effective Correction of Hemophagocytic Lymphohistiocytosis

Perforin-1 mutations result in a potentially fatal hemophagocytic lymphohistiocytosis (HLH) with heightened immune activation, hypercytokinemia, pancytopenia, and end-organ damage. At present, hematopoietic stem cell (HSC) transplantation is curative, but limited by donor availability and associated mortality, making gene therapy an attractive alternative approach for HLH. We reported that perforin expression driven by cellular promoters in lentiviral (LV) vectors resulted in significant, albeit partial, correction of the inflammatory features in a murine model of HLH. We hypothesized that the level of perforin expression achieved per cell from ectopic moderate-strength cellular promoters (phosphoglycerate kinase gene/perforin-1 gene) is inadequate and thus engineered an LV vector using a viral promoter (MND; a modified Moloney murine leukemia virus long terminal repeat with myeloproliferative sarcoma virus enhancer) containing microRNA126 target sequences to restrict perforin expression in HSCs. We show here that the MND-LV vector restored perforin expression to normal levels in a perforin-deficient human natural killer cell line and perforin gene-corrected Perforin1-/- transplant recipients, whereas cellular promoters drove only partial correction. On lymphocytic choriomeningitis virus challenge, the clinical scores and survival improved only with the MND-LV vector, but inflammatory markers and cytotoxicity were improved with all LV vectors. Our studies suggest that although moderate levels of expression can result in partial amelioration of the HLH phenotype, high levels of perforin expression per cell are required for complete correction of HLH.

High-Volume Hemofiltration in Critically Ill Patients With Secondary Hemophagocytic Lymphohistiocytosis/Macrophage Activation Syndrome: A Prospective Study in the PICU

OBJECTIVES

Hemophagocytic lymphohistiocytosis, which includes primary (familial) and secondary hemophagocytic lymphohistiocytosis, is a fatal disease in children. Macrophage activation syndrome was defined in patients who met secondary hemophagocytic lymphohistiocytosis criteria with an underlying autoimmune disease. High-volume hemofiltration has shown beneficial effects in severe sepsis and multiple organ dysfunction syndrome. Secondary hemophagocytic lymphohistiocytosis/macrophage activation syndrome shares many pathophysiologic similarities with sepsis. The present study assessed the effects of high-volume hemofiltration in children with secondary hemophagocytic lymphohistiocytosis/macrophage activation syndrome.

DESIGN

A single-center nonrandomized concurrent control trial.

SETTING

The PICU of Shanghai Children's Hospital, Shanghai Jiao Tong University.

PATIENTS

Thirty-three critically ill secondary hemophagocytic lymphohistiocytosis/macrophage activation syndrome patients treated between January 2010 and December 2014.

INTERVENTIONS

Thirty-three patients were divided into two groups: high-volume hemofiltration + hemophagocytic lymphohistiocytosis-2004 group (17 cases) or hemophagocytic lymphohistiocytosis-2004 group (16 cases). High-volume hemofiltration was defined as an ultrafiltrate flow rate of 50-70 mL/kg/hr. Clinical and biological variables were assessed before initiation and after 48 and 72 hours of high-volume hemofiltration therapy.

MEASUREMENTS AND MAIN RESULTS

The total mortality rate was 42.4% (14/33), but mortality at 28 days was not significantly different between the two groups (high-volume hemofiltration + hemophagocytic lymphohistiocytosis-2004 group: five deaths, 29.4%; hemophagocytic lymphohistiocytosis-2004 group: nine deaths, 56.3%; chi-square, 2.431; p = 0.119). Children received high-volume hemofiltration for 60.2 ± 42.0 hours. After 48 and 72 hours respectively, a significant decrease in serum ferritin (p < 0.001), aspartate aminotransferase (p = 0.037 and p < 0.001), total bilirubin (p = 0.041 and p = 0.037), and serum creatinine (p = 0.006 and p = 0.004) levels were observed. Furthermore, the natural killer-cell activity up-regulated (p = 0.047) after 72 hours. Furthermore, significantly decreased levels of serum tumor necrosis factor-α (from 91.5 ± 44.7 ng/L at 48 hr to 36.7 ± 24.9 ng/L at 72 hr; p = 0.007)) and interleukin-6 (from 46.9 ± 21.1 ng/L at 48 hr to 27.7 ± 14.5 ng/L at 72 hr; p < 0.0001) were observed. After 7 days, patients receiving high-volume hemofiltration had significantly lower bilirubin, creatinine, ferritin, procalcitonin, lactate dehydrogenase level, tumor necrosis factor-α, and interleukin-6 levels, and needed less mechanical ventilation compared with hemophagocytic lymphohistiocytosis-2004 group patients. No serious adverse events were observed.

CONCLUSIONS

High-volume hemofiltration may improve organ function by decreasing cytokine levels (tumor necrosis factor-α and interleukin-6). High-volume hemofiltration may be an effective adjunctive treatment in secondary hemophagocytic lymphohistiocytosis/macrophage activation syndrome.

Liver transplantation for children with acute liver failure associated with secondary hemophagocytic lymphohistiocytosis

Hemophagocytic lymphohistiocytosis (HLH) is a rare life-threatening systemic disease, characterized by overwhelming stimulation of the immune system and categorized as primary or secondary types. Occasionally, acute liver failure (ALF) may dominate the clinical presentation. Given the systemic nature of HLH and risk of recurrence, HLH is considered by many a contraindication to liver transplantation (LT). The aim of this study is to review our single-center experience with LT in children with secondary HLH and ALF (HLH-ALF). This is a cross-sectional, retrospective study of children with secondary HLH-ALF that underwent LT in 2005-2014. Of 246 LTs, 9 patients (3 males; median age, 5 years; range, 0.7-15.4 years) underwent LT for secondary HLH-ALF. Disease progression was rapid with median 14 days (range, 6-27 days) between first symptoms and LT. Low fibrinogen/high triglycerides, elevated ferritin, hemophagocytosis on liver biopsy, and soluble interleukin 2 receptor levels were the most commonly fulfilled diagnostic criteria; HLH genetic studies were negative in all patients. Immunosuppressive therapy after LT included corticosteroids adjusted to HLH treatment protocol and tacrolimus. Thymoglobulin (n = 5), etoposide (n = 4), and alemtuzumab (n = 2) were used in cases of recurrence. Five (56%) patients experienced HLH recurrence, 1 requiring repeat LT, and 3 died. Overall graft and patient survival were 60% and 67%, respectively. Six patients are alive and well at a median of 24 months (range, 15-72 months) after transplantation. In conclusion, LT can be beneficial in selected patients with secondary HLH-ALF and can restore good health in an otherwise lethal condition. Liver Transplantation 22 1245-1253 2016 AASLD.

Hemophagocytic lymphohistiocytosis associated with Epstein-Barr virus in the central nervous system

Hemophagocytic lymphohistiocytosis (HLH) is a rare immune hyperactivation syndrome which may be primary (genetic) or secondary to various immune-related conditions including infection, immunodeficiency, and malignancies. Rapid diagnosis and treatment are essential because it can be associated with significant morbidity and mortality. Epstein-Barr virus (EBV) is a known infectious cause of acquired HLH, but EBV-associated HLH involving the central nervous system is rare and not well characterized neuropathologically. We report a case of fatal EBV-associated HLH with severe involvement of the central nervous system showing florid hemophagocytosis in the choroid plexus, with extensive neuron loss and gliosis in the cerebrum, cerebellum, and brainstem.

A unique SNARE machinery for exocytosis of cytotoxic granules and platelets granules

Cytotoxic T lymphocytes (CTLs) and natural killer (NK) cells target infected or transformed cells with perforin-containing cytotoxic granules through immune synapses, while platelets secrete several types of granules which contents are essential for thrombosis and hemostasis. Recent work has culminated in the notion that an exocytic SNARE complex, based on a very similar set of components, is primarily responsible for exocytosis of the diverse granules in these different cell types. Granule exocytosis is, in particular, uniquely dependent on the atypical Q-SNARE syntaxin 11, its interacting partners of the Sec/Munc (SM) family, and is regulated by Rab27a. Mutations in these exocytic components underlie disease manifestations of familial hemophagocytic lymphohistiocytosis (FHL) subtypes, characterized by hyperactivation of the immune system, as well as platelet granule secretion defects. Here we discuss the key discoveries that led to the converging notion of the syntaxin 11-based exocytosis machinery for cytotoxic granules and platelet-derived granules.

Allogeneic hematopoietic stem-cell transplantation for adult and adolescent hemophagocytic lymphohistiocytosis: a single center analysis

Myeloablative conditioning-based allogeneic hematopoietic stem-cell transplantation (allo-HSCT) in the treatment of adult and adolescent hemophagocytic lymphohistiocytosis (HLH) is rarely reported. We conducted a retrospective study of 30 adult and adolescent HLH transplanted for primary HLH (n = 4), tumor-HLH (n = 8), EBV-HLH (n = 14), and underlying disease-unknown (UDU)-HLH (n = 4). Peripheral blood stem cells (PBSCs) were the stem-cell source in all patients. Twenty-three patients were transplanted from HLA-haploidentical family donors, six from HLA-identical sibling donors, and one from a matched unrelated donor. Four patients appeared with mixed chimerism (MC), and no patient presented with graft failure. There was a high risk for EBV reactivation with an incidence of 47 %. Two patients developed post-transplant lymphoproliferative disorder (PTLD) and three were considered primary disease recurrent. With a median follow-up of 26 months, 19 patients survived and 11 patients died. The estimated 2-year overall survival (OS) was 63.3 ± 8.8 % in all patients, 100 % in primary HLH, 64.3 ± 12.8 % in EBV-HLH, 50.0 ± 17.7 % in tumor-HLH, and 50.0 ± 25.0 % in UDU-HLH. Myeloablative conditioning-based allo-HSCT is an effective treatment for adult and adolescent HLH to achieve complete remission and long-term survival.

How genetic testing can lead to targeted management of XIAP deficiency-related inflammatory bowel disease

X-linked lymphoproliferative disease type 2 (XLP-2, OMIM 300635) is a primary immunodeficiency caused by the loss of X chromosome-linked inhibitor of apoptosis (XIAP), the X-linked inhibitor of apoptosis gene at Xq25. XLP-2 individuals are susceptible to several specific and potentially fatal infections, such as Epstein-Barr virus (EBV). Children with XIAP-related XLP-2 may present with either familial hemophagocytic lymphohistiocytosis, often triggered in response to EBV infection, or with a treatment-refractory severe pediatric form of inflammatory bowel disease (IBD) that might be diagnosed as Crohn disease. However, this monogenic cause of IBD is distinct from adult Crohn disease (a polygenic and multifactorial disease) in its etiology and responsiveness to therapy. XLP-2 and the associated IBD symptoms are managed by a reduced-intensity conditioning regimen with an allogeneic hematopoietic stem cell transplantation that causes resolution of gastrointestinal symptoms. Exome sequencing has enabled identification of XIAP-deficient diseased individuals and has altered their morbidity by providing potentially lifesaving strategies in a timely and effective manner. Here, we summarize XLP-2 IBD treatment history and patient morbidity/mortality since its original identification in 2006. Since XLP-2 is rare, cases are probably undergiagnosed or misdiagnosed. Consideration of XLP-2 in children with severe symptoms of IBD can prevent serious morbidities and mortality, avoid unnecessary procedures, and expedite specific targeted therapy.Genet Med 19 2, 133-143.

Profiling of EBV-Encoded microRNAs in EBV-Associated Hemophagocytic Lymphohistiocytosis

Epstein-Barr virus-associated hemophagocytic lymphohistiocytosis (EBV-HLH) is a life-threatening complication of EBV infection. MicroRNAs (miRNAs) were small non-coding RNA, and EBV could encode miRNAs that are involved in the progression of infection. However, the profiles of EBV-miRNAs in EBV-HLH were unknown. Here, we aimed to profile the expression of EBV-miRNAs in children with EBV-HLH by analyzing 44 known EBV-miRNAs, encoded within the BamHI fragment H rightward open reading frame 1 (BHRF1) and the BamHI-A region rightward transcript (BART), in plasma and cellular targets by real-time quantitative PCR. The study included 15 children with EBV-HLH, 15 children with infectious mononucleosis (IM), and 15 healthy controls. CD8(+) T cells were found to be the cellular target of EBV infection in EBV-HLH, while CD19(+) B cells were infected with EBV in IM. We also found the greater levels of several miRNAs encoded by BART in EBV-HLH, compared to those in IM and healthy controls, whereas the levels of BHRF1 miRNAs were lower than those in IM. The profile and pattern of EBV-miRNAs in EBV-HLH indicated that EBV could display type II latency in EBV-HLH. Importantly, the level of plasma miR-BART16-1 continued decreasing during the whole chemotherapy, suggesting that plasma miR-BART16-1 could be a potential biomarker for monitoring EBV-HLH progression. The pathogenesis of EBV-HLH might be attributed to the abundance of EBV-miRNAs in EBV-HLH. These findings help elucidate the roles of EBV miRNAs in EBV-HLH, enabling the understanding of the basis of this disease and providing clues for its treatment.

[Successful Treatment of Seasonal Influenza A (H3N2) infection-related Hemophagocytic Lymphocytosis in an Elderly Man]

A 79-year-old man experienced severe chronic obstructive pulmonary disease (COPD) and was receiving treatment for ischemic heart disease. Starting from dizziness and chilliness, he lost consciousness after few days. He was taken to our emergency department. On initial evaluation, he complained of dyspnea and was afebrile with a pulse rate, blood pressure, and respiratory rate of 105 beats/min, 112/98mmHg, and 28 breath/min, respectively. His respiratory sounds were clear and chest radiography did not show any abnormal shadows, but his arterial blood gas examination showed type II respiratory failure. Because the nasopharyngeal seasonal influenza A virus (IAV) test was positive, the patient was admitted with the diagnosis of acute exacerbation of COPD due to IAV. We administered peramivir, a specific anti-influenza drug, and started mechanical ventilation. Over time, he started to show signs of disseminated intravascular coagulation, such as multiple organ failure and thrombocytopenia. Subsequently, blood tests showed elevation of ferritin and soluble interleukin 2 receptor (sIL2R); microscopic examination of the peripheral blood revealed hemophagocytosis. Secondary hemophagocytic lymphohistiocytosis (HLH) due to IAV was diagnosed and together with corticosteroid therapy, intravenous gamma globulin was administered from the 3rd clinical day. The patint was saved with our early diagnosis and treatment of HLH and was discharged on the 92nd clinical day. Viral-induced HLH, formerly known as virus-associated hemophagocytic syndrome (VAHS), leads to multiple organ failure due to a cytokine storm scattered by viral-infected pathogenic inflammatory cells. It is well known that pandemic swine flu causes secondary HLH leading to poor outcomes. Currently, not much is known about HLH due to seasonal flu; particularly, IAV (H3N2)-related HLH cases are rare and reported cases showed poor outcomes as well. With an early diagnosis and minimum immunotherapy, we report herein on a case of IAV (H3N2)-related HLH which was treated successfully.

Macrophage activation syndrome in the era of biologic therapy

Macrophage activation syndrome (MAS) refers to acute overwhelming inflammation caused by a 'cytokine storm'. Although increasingly recognized as a life-threatening complication of various rheumatic diseases, clinically, MAS is strikingly similar to primary and secondary forms of haemophagocytic lymphohistiocytosis (HLH). Not surprisingly, many rheumatologists prefer the term secondary HLH rather than MAS to describe this condition, and efforts to change the nomenclature are in progress. The pathophysiology of MAS remains elusive, but observations in animal models, as well as data on the effects of new anticytokine therapies on rates and clinical presentations of MAS in patients with systemic juvenile idiopathic arthritis (sJIA), provide clues to the understanding of this perplexing clinical phenomenon. In this Review, we explore the latest available evidence and discuss potential diagnostic challenges in the era of increasing use of biologic therapies.

Current Updates on Classification, Diagnosis and Treatment of Hemophagocytic Lymphohistiocytosis (HLH)

Hemophagocytic lymphohistiocytosis (HLH) is a life threatening hyperinflammatory syndrome characterized by excessive activation of macrophages and T cells resulting from defective cytotoxicity. Severe hyperinflammation caused by uncontrolled proliferation of activated lymphocytes and histiocytes (macrophages) secreting high amounts of inflammatory cytokines threatens the life of the patient and may lead to death unless arrested by appropriate treatment. HLH can be caused either by certain underlying genetic diseases (familial HLH), or may also occur due to particular triggers in patients with no known inherited disorder (acquired HLH). Due to life threatening nature of the disease, early diagnosis and initiation of immunosuppressive therapy is extremely important. HLH diagnosis is based on constellation of clinical manifestations and laboratory parameters which often overlap with those of severe infection or sepsis. Identification of patients with familial HLH and their underlying genetic defects requires specialized laboratory tests and is important for predicting relapses and planning early therapeutic hematopoietic stem cell transplantation (HSCT). A high suspicion and thorough clinical, immunological and genetic work-up is required for diagnosis of HLH. Prompt initiation of adequate treatment is essential for the survival. Substantial progress has been made in exploring the complex cause and pathophysiology of HLH and also in management of HLH patients.

Progressive Diffuse Osteonecrosis in a Patient with Secondary Hemophagocytic Lymphohistiocytosis

This is a case report with serial imaging showing progression of diffuse osteonecrosis in a patient after a diagnosis of secondary hemophagocytic lymphohistiocytosis (HLH). While bone marrow involvement in HLH has been long noted at histological evaluation and is itself one of the diagnosis criteria, to the best of our knowledge, there has been no previous publication addressing osseous image findings in a patient with HLH.

Hemophagocytic lymphohistiocytosis secondary to Epstein Barr virus and Leishmania co-infection in a toddler

This is the report of an EBV + Leishmanial co-infection. The patient developed hemophagocytic syndrome (HLH) and was treated with the standard HLH-2004 protocol. However, PCR in bone marrow discovered this secondary cause for HLH. In endemic countries, visceral leishmaniasis should be considered in the differential diagnosis even in EBV-related HLH, as chemotherapy toxicity may be avoided.

Adult-onset central nervous system hemophagocytic lymphohistiocytosis: a case report

Background

Hemophagocytic lymphohistiocytosis (HLH) is a clinical syndrome with both genetic and acquired causes characterized by elevated cytokine levels, hyperinflammation, and overactivation of lymphocytes and macrophages. It is typically a systemic disease with variable degrees of CNS involvement. Cases with predominantly central nervous system (CNS) involvement are very rare, with the vast majority of these occurring in infants and young children. This report documents a case of adult-onset CNS-HLH involving a middle-aged man.

Case presentation

A 55 year-old man developed progressive left hemiparesis and aphasia over the course of several months. Brain MRI showed multifocal, mass-like enhancing lesions with increased susceptibility consistent with blood products. An extensive workup for infectious, autoimmune, and neoplastic etiologies was significant only for a markedly elevated serum ferritin at 1456 ng/mL. Two brain biopsies showed a non-specific inflammatory process. The patient was treated empirically with steroids and plasmapheresis, but he continued to suffer a progressive neurological decline and died one year after onset of neurological symptoms. Autopsy revealed profound histiocytic infiltration, perivascular lymphocytosis, and emperipolesis, compatible with CNS-HLH.

Conclusion

This case report describes an exceedingly rare presentation of an adult patient with CNS predominant HLH. This diagnosis should be considered in the differential diagnosis of adults presenting with progressive brain lesions, even in the absence of typical systemic signs of HLH.

Haemophagocytic lymphohistiocytosis in inflammatory bowel disease with virus infection

Patients with inflammatory bowel disease (IBD) are at risk of developing haemophagocytic lymphohistiocytosis (HLH) because of chronic systemic inflammation as well as exposure to immunosuppressive medications. The two main causes of HLH in IBD patients are infection with cytomegalovirus and Epstein-Barr virus. Patients with Crohn's disease are more susceptible to HLH than those with ulcerative colitis. The majority of cases are seen in people receiving an immunosuppressive regimen that included thiopurines.

Hematopoietic cell transplantation for hemophagocytic lymphohistiocytosis: recent advances and controversies

Hemophagocytic lymphohistiocytosis (HLH) is a life-threatening hyperinflammatory clinical syndrome of uncontrolled immune response which results in hypercytokinemia due to underlying primary or secondary immune defect. A number of genetic defects in transport, processing and function of cytotoxic granules which result in defective granule exocytosis and cytotoxicity of cytotoxic T lymphocytes (CTL) and natural killer (NK) cells have been well identified at the cellular and molecular level. Important advances have been made during the last 20 years in the diagnosis and treatment of HLH. The Histiocyte Society has proposed diagnostic guideline using both clinical and laboratory findings in HLH-2004 protocol, and this has been modified partly in 2009. HLH used to be a fatal disease, but the survival of HLH patients has improved to more than 60% with the use of chemoimmunotherapy combined with hematopoietic cell transplantation (HCT) over the past 2 decades. However, HCT is still the only curative option of treatment for primary HLH and refractory/relapsed HLH after proper chemoimmunotherapy. The outcome of HCT for HLH patients was also improved steadily during last decades, but HCT for HLH still carries significant mortality and morbidity. Moreover, there remain ongoing controversies in various aspects of HCT including indication of HCT, donor selection, timing of HCT, conditioning regimen, and mixed chimerism after HCT. This review summarized the important practical issues which were proven by previous studies on HCT for HLH, and tried to delineate the controversies among them.

Lentivirus technologies for modulation of the immune system

Lentiviral vectors (LVV) are important tools for the treatment of immune system disorders. Integration of therapeutic genetic material into the haematopoietic stem cell compartment using LVV can mediate long-term correction of haematopoietic lineages, thereby correcting disease phenotypes. Twenty years of vector development have successfully brought LVV to the clinic, with follow up studies of clinical trials treating primary immunodeficiencies now being reported. Results have demonstrated clear improvements in the quality of life for patients with a number of conditions in the absence of the severe adverse events observed in earlier retroviral gene therapy trials. Growing interest in gene modified adoptive T cell transfer as an alternative strategy has driven further technology innovation, including characterisation of novel viral envelopes. We will also discuss the progression of gene editing technology to preclinical investigations in models of immune deficiency.

Cerebrospinal Fluid Markers of Macrophage and Lymphocyte Activation After Traumatic Brain Injury in Children

OBJECTIVES

The magnitude and role of the cellular immune response following pediatric traumatic brain injury remains unknown. We tested the hypothesis that macrophage/microglia and T-cell activation occurs following pediatric traumatic brain injury by measuring cerebrospinal fluid levels of soluble cluster of differentiation 163 and ferritin and soluble interleukin-2 receptor α, respectively, and determined whether these biomarkers were associated with relevant clinical variables and outcome.

DESIGN

Retrospective analysis of samples from an established, single-center cerebrospinal fluid bank.

SETTING

PICU in a tertiary children's hospital.

PATIENTS

Sixty-six pediatric patients after severe traumatic brain injury (Glasgow Coma Scale score < 8) who were 1 month to 16 years old and 17 control patients who were 1 month to 14 years old.

INTERVENTIONS

None.

MEASUREMENTS AND MAIN RESULTS

Cerebrospinal fluid levels of soluble cluster of differentiation 163, ferritin, and soluble interleukin-2 receptor α were determined by enzyme-linked immunosorbent assay at two time points (t1 = 17 ± 10 hr; t2 = 72 ± 15 hr) for each traumatic brain injury patient. Cerebrospinal fluid levels of soluble cluster of differentiation 163, ferritin, and soluble interleukin-2 receptor α after traumatic brain injury were compared with controls and analyzed for associations with age, patient sex, initial Glasgow Coma Scale score, diagnosis of abusive head trauma, the presence of hemorrhage on CT scan, and Glasgow Outcome Scale score. Cerebrospinal fluid level of soluble cluster of differentiation 163 was increased in traumatic brain injury patients at t2 versus t1 and controls (median, 95.4 ng/mL [interquartile range, 21.8-134.0 ng/mL] vs 31.0 ng/mL [5.7-77.7 ng/mL] and 27.8 ng/mL [19.1-43.1 ng/mL], respectively; p < 0.05). Cerebrospinal fluid level of ferritin was increased in traumatic brain injury patients at t2 and t1 versus controls (8.3 ng/mL [<7.5-19.8 ng/mL] and 8.9 ng/mL [<7.5-26.7 ng/mL] vs <7.5 ng/mL below lower limit of detection, respectively; p < 0.05). Cerebrospinal fluid levels of soluble interleukin-2 receptor α in traumatic brain injury patients at t2 and t1 were not different versus controls. Multivariate regression revealed associations between high ferritin and age 4 years or younger, lower Glasgow Coma Scale score, abusive head trauma, and unfavorable Glasgow Outcome Scale score.

CONCLUSIONS

Children with traumatic brain injury demonstrate evidence for macrophage activation after traumatic brain injury, and in terms of cerebrospinal fluid ferritin, this appears more prominent with young age, initial injury severity, abusive head trauma, and unfavorable outcome. Further study is needed to determine whether biomarkers of macrophage activation may be used to discriminate between aberrant and adaptive immune responses and whether inflammation represents a therapeutic target after traumatic brain injury.

Hyperinflammation, rather than hemophagocytosis, is the common link between macrophage activation syndrome and hemophagocytic lymphohistiocytosis

PURPOSE OF REVIEW

Macrophage activation syndrome is the rheumatic disease-associated member of a group of hyperinflammatory syndromes characterized by uncontrolled cytokine storm. In this review, we highlight recent publications related to the pathoetiology of hyperinflammatory syndromes with an emphasis on how this new knowledge will guide our diagnosis, treatment, and future research efforts to better understand these deadly conditions.

RECENT FINDINGS

The heterogeneity of clinical manifestations seen in patients with hyperinflammatory syndromes continues to grow as novel genetic and immunotherapeutic triggers of cytokine storm have been identified. Recent studies characterize unique cytokine and gene expression profiles from patients with different hyperinflammatory syndromes, whereas novel murine models begin to define networks of immune dysregulation thought to drive excessive inflammation in cytokine storm.

SUMMARY

Emerging evidence suggests hypercytokinemia is the driving cause of immunopathology and morbidity/mortality in hyperinflammatory syndromes. Therefore, approaches to block cytokine function may be fruitful in treating hyperinflammatory syndromes with less toxicity than current therapies. However, not all hyperinflammatory syndromes result in the same pathogenic cytokine profile, implying that a personalized approach will be required for effective use of anticytokine therapies in the treatment of hyperinflammatory syndromes.

An uncommon presentation of EBV-driven HLH. Primary or secondary? An ongoing dilemma

Haemophagocytic lymphohistiocytosis (HLH) is a potentially fatal syndrome, mainly characterised by dysregulated immune activation. The syndrome is related to a genetic cause, in the classic primary form, or to identified triggers such as infections, malignancy or rheumatological processes, in the classic secondary form. Epstein-Barr virus (EBV) is the most common agent implicated in hereditary and non-hereditary conditions. We describe a 23-month-old girl who experienced severe clinical deterioration with respiratory distress due a bilateral pleural effusion within the first week of primary EBV infection. Fever, generalised oedema and hepatosplenomegaly, along with a pruritic morbilliform erythematous rash, were the first clinical signs. Respiratory impairment followed with hypoxaemia and the patient was admitted to the intensive care unit for thoracocentesis. Further investigation showed persistent bicytopaenia, hypertriglyceridaemia, hyperferritinaemia and elevated α chain of interleukin-2 receptor (sCD25). Diagnostic criteria for HLH were fulfilled. Therapy was instituted with dexamethasone, ciclosporin A and intravenous immunoglobulin 6 days after admission with progressive clinical recovery.

Histoplasmosis-Induced Hemophagocytic Syndrome: A Case Series and Review of the Literature

Background. Histoplasmosis-associated hemophagocytic lymphohistiocytosis (HLH) is a relatively rare disorder for which data are limited regarding optimal treatment and clinical outcomes in adults. We describe the clinical features, treatment, and outcomes of patients with histoplasmosis-associated HLH at our institution.

Methods. We performed a retrospective chart review of all inpatients at Parkland Hospital diagnosed with HLH associated with Histoplasma capsulatum from 2003 to 2013.

Results. Eleven cases of histoplasmosis-associated HLH over this time period were identified. Nine of eleven cases were males (82%). Nine of these patients had human immunodeficiency virus (HIV)/acquired immune deficiency syndrome (AIDS), 1 was a renal transplant patient on immunosuppressants, and the other had no documented immunocompromise. The most common HLH criteria were splenomegaly (n = 10), fever (n = 10), and ferritin >500 ng/dL (n = 9). Urine Histoplasma antigen was positive in every patient tested (n = 9 of 9), and most antibodies for Histoplasma were positive if checked (n = 4 of 5). A majority of patients received liposomal amphotericin B (n = 9) with an average treatment duration of 11 days, and 5 patients also received prednisone, intravenous immunoglobulin (IVIG), or both. Overall, 5 patients died within 30 days (45.5%), and 7 patients died within 90 days (63.6%). Of the 5 patients that received immunosuppression, 4 died (80%), whereas in the group not given additional immunosuppression (n = 5), 2 died (40%).

Conclusions. Histoplasmosis-associated HLH among adults is a lethal disease of highly immunocompromised patients, especially patients with HIV/AIDS. Clinical features such as splenomegaly, elevated ferritin, and cytopenias should prompt evaluation for HLH in this population. Further data are needed to define the role of immunosuppression, IVIG, and highly active antiretroviral therapy in treating this condition.

How I treat hemophagocytic lymphohistiocytosis in the adult patient

Hemophagocytic lymphohistiocytosis (HLH) is a devastating disorder of uncontrolled immune activation characterized by clinical and laboratory evidence of extreme inflammation. This syndrome can be caused by genetic mutations affecting cytotoxic function (familial HLH) or be secondary to infectious, rheumatologic, malignant, or metabolic conditions (acquired HLH). Prompt recognition is paramount and, without early treatment, this disorder is frequently fatal. Although HLH is well described in the pediatric population, less is known about the appropriate work-up and treatment in adults. Here, we review the clinical characteristics, diagnosis, and treatment of HLH in adults.

Clinical characteristics, prognostic factors, and outcomes of adult patients with hemophagocytic lymphohistiocytosis

Hemophagocytic lymphohistiocytosis (HLH) is a rare clinical syndrome characterized by the activation of the mononuclear phagocytic system. The diagnosis of HLH in adults is challenging not only because the majority of the reported data are from pediatric patients, but also because HLH occurs in many disease entities. This study reports the clinical and laboratory findings and prognostic factors of adult HLH in a large cohort managed at a single medical center from 2003 to 2014. Seventy-three patients met the HLH-2004 diagnostic criteria. The median age was 51 years (range, 18-82 years); 41 (56.2%) were male. Patients manifested fever, cytopenias, and elevated ferritin in >85% of cases. Likely causes of HLH were as follows: 30 (41.1%) infections, 21 (28.8%) malignancies, 5 (6.8%) attributed to autoimmune disorders, 1 (1.4%) primary immunodeficiency, 2 (2.7%) post solid organ transplantation, and 13 (17.8%) idiopathic. The median overall survival was 7.67 months. Patients with malignancy-associated HLH had a markedly worse survival compared with patients with non-malignancy-associated HLH (median overall survival 1.13 vs. 46.53 months, respectively; P < 0.0001). In a multivariable analysis, malignancy (hazard ratio = 12.22; 95% CI: 2.53-59.02; P = 0.002) correlated with poor survival. Ferritin >50,000 µg/L correlated with 30-day mortality. Survival after a diagnosis of HLH is dismal, especially among those with malignancy-associated HLH. The development of a registry for adults with HLH would improve our understanding of this syndrome, validate diagnostic criteria, and help develop effective treatment strategies.

Clinical characteristics and prognostic factors of adult hemophagocytic syndrome patients: a retrospective study of increasing awareness of a disease from a single-center in China

Background

Hemophagocytic lymphohistiocytosis (HLH) is a relatively rare but life-threatening disease with confusing clinical manifestations, rapidly deteriorating health, high morbidity and mortality.

Methods

To improve the recognition as well as understanding of this disorder, we analyzed clinical characteristics and prognostic factors from 85 adult patients diagnosed with HLH in our hospital from April 2005 to June 2014.

Results

Patients with HLH displayed variable clinical markers across a wide spectrum. These included fever and hyperferritinemia (100%), elevated lactate dehydrogenase (LDH) (98.8%), two or three cytopenia (92.2%), splenomegaly (72.9%), hypofibrinogenemia (69.4%), hypertriglyceridemia (64.7%), hemophagocytosis (51.7%), and hepatomegaly (24.7%). Patients with active Epstien-Barr Virus (EBV) infection had a median overall survival (OS) of 65 days. Those displaying malignancy had very poor survival (median OS: 40 days). However, patients in rheumatic and non-EBV infection groups had relatively superior prognosis (not reached). Univariate analysis showed that Fibrinogen (Fbg) <1.5 g/L, platelet number (PLT) <40 × 10⁹/L and LDH ≥1000 U/L were factors that negatively affected survival (P = 0.004, 0.000, 0.002). Multivariate analysis showed that PLT <40 × 10⁹/L was the independent adverse factor (HR = 0.350, 95% CI: 0.145-0.844, P = 0.019).

Conclusions

HLH had very complex clinical manifestations and high death rate. Patients with active EBV infection, malignancy, Fbg <1.5 g/L, PLT <40 × 10⁹/L and LDH ≥1000 U/L had high risk of death as well as inferior survival, and these patients require systemic targeted treatments as early as possible.