Pathogenesis and mechanism of disease progression from hemophagocytic lymphohistiocytosis to Epstein-Barr virus-associated T-cell lymphoma: nuclear factor-kappa B pathway as a potential therapeutic target

Brain MRI imaging markers associated with death in children with central nervous system involvement of hemophagocytic lymphohistiocytosis

OBJECTIVES

To investigate the association of brain MRI and clinical variables with death in children with central nervous system involvement of hemophagocytic lymphohistiocytosis (CNS-HLH).

METHODS

Clinical and brain MRI data of children with CNS-HLH from January 2012 to March 2022 were reviewed retrospectively. Patients were divided into the deceased group and the surviving group. The intergroup differences of seven brain MRI variables, twelve clinical variables, and underlying diseases were studied.

RESULTS

One hundred and fourteen patients were included in this study, consisting of 59 who died and 55 who survived. The included clinical variables did not show statistically independent correlation with patients' deaths. For MRI variables, a multivariate analysis demonstrated restricted diffusion of lesion (OR = 9.64, 95% CI: 3.39-27.43, p < 0.001) and count of affected brain regions (CABR) (OR = 1.24, 95% CI: 1.03-1.49, p = 0.02) were independent risk factors for death. ROC curve showed CABR (AUC = 0.79, 95% CI: 0.70-0.87, p < 0.001) is highly predictive for mortality with an optimal cutoff value of 4.5 (sensitivity 76%, specificity 73%). For HLH subtypes, familial HLH (F-HLH, OR = 9.90, 95% CI: 2.01-48.87, p = 0.005) and immune-compromise-related HLH (IC-HLH, OR = 4.95, 95% CI: 1.40-17.46, p = 0.01) presented statistically stronger association with death than infection-related HLH. F-HLH and IC-HLH preferred to have large lesions, restricted diffusion, and more brain regions involved than other subtypes.

CONCLUSION

Brain MRI features exhibit independent prediction for mortality in children with CNS-HLH, and HLH subtypes pose effects on patient outcomes and brain MRI findings.

CLINICAL RELEVANCE STATEMENT

The number of affected brain regions and diffusion restriction of lesion exhibit significant correlation with mortality in children diagnosed with CNS-hemophagocytic lymphohistiocytosis, and may serve as candidate MRI markers for the prediction of the disorder's severity.

KEY POINTS

• The brain MRI markers, restricted diffusion of lesion and count of affected brain regions, significantly correlated with death. • Familial and immune-compromise-related hemophagocytic lymphohistiocytosis presented statistically stronger association with death than infection-related subtype. • Brain MRI is potential in death-predicting for children with central nervous system involvement of hemophagocytic lymphohistiocytosis.

The emerging role of anti-PD-1 antibody-based regimens in the treatment of extranodal NK/T-cell lymphoma-associated hemophagocytic lymphohistiocytosis

PURPOSE

Anti-PD-1 antibody (anti-PD-1 mAb) showed favorable outcomes in some patients with relapsed/refractory (r/r) extranodal NK/T-cell lymphoma (ENKTL). However, the role of anti-PD-1 antibody in NK/T-cell lymphoma-associated hemophagocytic lymphohistiocytosis (NK/T-LAHS) remains unclear. Here, we evaluated the efficacy and toxicity of anti-PD-1 antibody-based treatment in NK/T-LAHS patients.

METHODS

The clinical data of 98 patients diagnosed with NK/T-LAHS at Sun Yat-sen University Cancer Center and the First Affiliated Hospital of Guangdong Pharmaceutical University from May 2014 to November 2021 were retrospectively analyzed. All patients received anti-HLH [HLH-2004 (etoposide, dexamethasone, cyclosporine A) or DEP-based (liposomal doxorubicin, etoposide, methylprednisolone)] regimen and sequential anti-ENKTL chemotherapy (ChT) combined with anti-PD-1 antibody or not.

RESULTS

The overall response rate (ORR) of the anti-PD-1 mAb plus ChT regimens was higher than that of the ChT regimens (73.3% vs. 45.5%, P = 0.041). The toxicity of the anti-PD-1 mAb plus ChT regimens was tolerable. Except for higher rate of neutropenia, no significant difference in adverse events (AEs) was observed between the two groups. When the optimal response to anti-ENKTL was achieved, the median EBV DNA levels in patients who received anti-PD-1 mAb plus ChT were significantly lower than patients who received ChT only (878 copies/mL vs. 18,600 copies/mL, P = 0.001). With a median follow-up of 26.6 months (range 0-65.9 months), the median overall survival (mOS) was 3.5 months (95% CI：2.3-4.7 months). Patients treated with anti-PD-1 mAb plus ChT experienced a longer mOS than those who received ChT only [5.2 months (95% CI: 2.5-7.8 months) vs. 1.5 months (95% CI: 0.5-2.6 months), P = 0.002]. Cox multivariate analysis found that anti-PD-1 mAb was an independent prognostic factor for all NK/T-LAHS patients.

CONCLUSION

In conclusion, anti-PD-1 mAb combined with ChT regimens seemed to be associated with prolonged survival in NK/T-LAHS patients and may represent a potentially promising treatment strategy for this population.

The pathophysiology and current treatments for the subcutaneous panniculitis-like T cell lymphoma: An updated review

Subcutaneous panniculitis-like T cell lymphoma (SPTCL) is a rare cutaneous T cell lymphoma, which is indolent in nature but could claim life if not correctly diagnosed and promptly treated. SPTCL is usually presented clinically as painless subcutaneous and erythematous nodules over the trunk or extremities. Active clinical vigilance for these subcutaneous nodules or panniculitis-like lesions is warranted. A biopsy must be performed in order to make a correct diagnosis. Positron emission tomography scan is utilized for disease staging and treatment follow-up. Due to the rarity of this lymphoma, a standard treatment protocol is not established yet. However, most cases of SPTCL could be treated well under immunosuppressive or polychemotherapeutic drugs except in cases with hemophagocytic syndrome. Hematopoietic stem cell transplantation may be used in refractory or relapse cases. In this review, we presented a case of SPTCL with long-term complete remission. Meanwhile, since most clinical evidences and experiences of SPTCL are based mostly on case reports or small case series, and the understanding of the SPTCL pathophysiology is limited, we reviewed and updated the pathophysiology and treatments of SPTCL.

Matrin3 (MATR3) Expression Is Associated with Hemophagocytosis

Hemophagocytic lymphohistiocytosis (HLH) is a life-threatening hyperinflammatory syndrome characterized by prolonged fever, cytopenia, hepatosplenomegaly, and hemophagocytosis. This occurs as a result of activated macrophages and impaired function of natural killer cells and/or cytotoxic T lymphocytes. The NF-κB pathway plays a crucial role in hyperinflammation. Matrin3 (MATR3) is a nuclear RNA/DNA-binding protein that plays multiple roles in the regulation of gene expression. We enroll 62 patients diagnosed with secondary HLH and hemophagocytosis. Peripheral blood (PB) from 25 patients and 30 healthy volunteers and good quality bone marrow (BM) samples from 47 patients are collected and used for analysis. Clinical parameters, including age, sex, etiology, ferritin, fibrinogen, triglyceride, and viral infection status, had no association with survival prediction. Patients with downregulation of NF-κB and MATR3mRNA expression in the BM had a higher mortality rate. MATR3mRNA expression in PB was lower in patients compared to that in healthy volunteers. We use shRNA-MATR3-KD-THP1 cells to determine the efficacy of phagocytosis. We note that shRNA-MATR3-KD-THP1 cells had a higher phagocytic effect on necrotic Jurkat E6 cells and carboxylate modified polystyrene latex beads. Herein, we provide evidence of a new marker for clinical translation that can serve as a potential treatment target for secondary HLH.

Immunosuppressive Tumor Microenvironment and Immunotherapy of Epstein–Barr Virus-Associated Malignancies

The Epstein–Barr virus (EBV) can cause different types of cancer in human beings when the virus infects different cell types with various latent patterns. EBV shapes a distinct and immunosuppressive tumor microenvironment (TME) to its benefit by influencing and interacting with different components in the TME. Different EBV-associated malignancies adopt similar but slightly specific immunosuppressive mechanisms by encoding different EBV products to escape both innate and adaptive immune responses. Strategies reversing the immunosuppressive TME of EBV-associated malignancies have been under evaluation in clinical practice. As the interactions among EBV, tumor cells, and TME are intricate, in this review, we mainly discuss the epidemiology of EBV, the life cycle of EBV, the cellular and molecular composition of TME, and a landscape of different EBV-associated malignancies and immunotherapy by targeting the TME.

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

RATIONALE

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

PATIENT CONCERNS

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

DIAGNOSIS

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

INTERVENTIONS

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

OUTCOMES

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

LESSONS

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

Update on Molecular Diagnosis in Extranodal NK/T-Cell Lymphoma and Its Role in the Era of Personalized Medicine

Natural killer (NK)/T-cell lymphoma (NKTCL) is an aggressive malignancy with unique epidemiological, histological, molecular, and clinical characteristics. It occurs in two pathological forms, namely, extranodal NKTCL (ENKTCL) and aggressive NK leukemia, according to the latest World Health Organization (WHO) classification. Epstein–Barr virus (EBV) infection has long been proposed as the major etiology of lymphomagenesis. The adoption of high-throughput sequencing has allowed us to gain more insight into the molecular mechanisms of ENKTCL, which largely involve chromosome deletion and aberrations in Janus kinase (JAK)-signal transducer and activator of transcription (STAT), programmed cell death protein-1 (PD-1)/PD-ligand 1 (PD-L1) pathways, as well as mutations in tumor suppressor genes. The molecular findings could potentially influence the traditional chemoradiotherapy approach, which is known to be associated with significant toxicity. This article will review the latest molecular findings in NKTCL and recent advances in the field of molecular diagnosis in NKTCL. Issues of quality control and technical difficulties will also be discussed, along with future prospects in the molecular diagnosis and treatment of NKTCL.

F-18 FDG PET/CT in NK/T-Cell Lymphoma that Progressed from Epstein-Barr Virus-Associated Hemophagocytic Lymphohistiocytosis

Hemophagocytic lymphohistiocytosis (HLH) is a syndrome involving an uncontrolled immune response with variable triggers. HLH is rare but highly fatal, even with proper treatment; therefore, early recognition and diagnosis are crucial for management. Although the role of F-18 fluorodeoxyglucose (FDG) positron emission tomography/computed tomography (PET/CT) in HLH is poorly defined, it can provide valuable information on disease status and possible triggers. Herein, we report an F-18 FDG PET/CT study on a case of NK/T-cell lymphoma that progressed from Epstein-Barr virus-associated HLH.

Immune cartography of macrophage activation syndrome in the COVID-19 era

A hyperinflammatory 'cytokine storm' state termed macrophage activation syndrome (MAS), culminating from a complex interplay of genetics, immunodeficiency, infectious triggers and dominant innate immune effector responses, can develop across disparate entities including systemic juvenile idiopathic arthritis (sJIA) and its counterpart adult-onset Still disease (AOSD), connective tissue diseases, sepsis, infection, cancers and cancer immunotherapy. Classifying MAS using the immunological disease continuum model, with strict boundaries that define the limits of innate and adaptive immunity, at one boundary is MAS with loss of immune function, as occurs in the 'perforinopathies' and some cases of sJIA-AOSD. Conversely, at the other boundary, immune hypersensitivity with gain of immune function in MHC class II-associated sJIA-AOSD and with chimeric antigen receptor (CAR) T cell therapy also triggers MAS. This provides a benchmark for evaluating severe inflammation in some patients with COVID-19 pneumonia, which cripples primary type I interferon immunity and usually culminates in a lung-centric 'second wave' cytokine-driven alveolitis with associated immunothrombosis; this phenomenon is generally distinct from MAS but can share features with the proposed 'loss of immune function' MAS variant. This loss and gain of function MAS model offers immune cartography for a novel mechanistic classification of MAS with therapeutic implications.

MRI findings of central nervous system involvement in children with haemophagocytic lymphohistiocytosis: correlation with clinical biochemical tests

AIM

To investigate the brain magnetic resonance imaging (MRI) features of children with haemophagocytic lymphohistiocytosis (HLH) with central nervous system (CNS) involvement, and to investigate the correlation with clinical biochemical tests.

MATERIAL AND METHODS

Clinical and MRI data were collected from 118 children with HLH-CNS between January 2012 and June 2019. Patients were grouped according to their MRI findings, and statistical methods were used to test for correlations between the MRI findings and biochemical variables.

RESULTS

Patients were divided into three groups, including normal appearance (Group 1, 17/118), diffuse parenchymal volume loss (Group 2, 44/118), and brain parenchyma lesions (Group 3, 57/118) containing three subtypes of brain lesions and HLH-CNS complications. Comparing biochemical values among the three groups revealed a significant difference for all values (p<0.05), except for cell counts in the cerebrospinal fluid (CSF). A pairwise comparison further showed significant inter-group differences for most of the variables. Spearman's rank correlation coefficient also demonstrated that CSF cell counts (r=0.193, p=0.036), CSF microprotein content (r=0.379, p<0.001), serum aspartate aminotransferase (AST; r=0.521, p<0.001), serum lactate dehydrogenase (LDH; r=0.514, p<0.001) and activated partial thromboplastin time (APTT; r=0.326, p<0.001) correlated positively with the MRI groups, while platelet count (PLT; r=-0.633, p<0.001) and plasma fibrinogen (FIB; r=-0.258, p=0.005) correlated negatively.

CONCLUSION

Classification of brain MRI findings of HLH-CNS correlates well with the results of several key biochemical tests. Brain MRI is a promising method to elucidate illness severity and clinical outcomes.

The landscape of new drugs in extranodal NK/T-cell lymphoma

To date, much progress has been made in early-stage extranodal NK/T-cell lymphoma (ENKTCL), and risk-adapted therapy with radiotherapy (RT) alone for the low-risk group and RT combined with asparaginase-based chemotherapy (CT) for the high-risk group yields favorable outcomes. However, optimal treatment strategies have not been defined yet for advanced-stage ENKTCL. Historically, ENKTCL responded poorly to conventional anthracycline-based chemotherapy probably because of inherent multidrug resistance (MDR). The fact that ENKTCL cells lack asparagine synthetase (ASNS) activity warranted the use of L-asparaginase or pegaspargase as frontline chemotherapies. Even though, due to high mortality of the disease, approximately 50% patients failing the frontline therapy arrived at dismal clinical outcomes with a median progression-free survival (PFS) less than 8 months. As distinctive molecular and biological subgroups are increasingly discovered within the disease entity of ENKTCL, novel targeted therapies and immunotherapy are of the urgent need for those heterogeneous subgroups. In this review, we sought to summarize the preclinical and clinical results of 6 categories of promising targeted therapy and immunotherapy for the treatment of ENKTCL, including monoclonal antibodies, immune checkpoint inhibitors, small-molecular inhibitors, epigenetic therapy, immunomodulatory drugs, and adoptive T-cell therapy, and these might change the landscape of treatment for ENKTCL in the near future.

Hemophagocytic lymphohistiocytosis is associated with Bartonella henselae infection in a patient with multiple susceptibility genes

BACKGROUND

Adult-onset hemophagocytic lymphohistiocytosis (HLH) is a rare and life-threatening condition, which is often triggered by certain types of infection, cancer and numerous autoimmune diseases; however, of the numerous infectious triggers associated with HLH, the consequences of Bartonella henselae infection have been rarely reported.

CASE PRESENTATION

A 48-year-old female presented with a 20-day history of intermittent fever accompanied by systemic rash, fatigue, anorexia and weight loss later she developed shock and unconsciousness. Blood tests showed a reduction of leukocyte, anemia and thrombocytopenia, and pathological results of a bone marrow biopsy confirmed hemophagocytic activity. Metagenomic next-generation sequencing (mNGS) analysis of the lymph node detected the presence of B. henselae. Whole exome sequencing revealed two gene variants, STXBP2 and IRF5, in this adult patient with secondary HLH. Then, she received minocycline and rifampin combination anti-infective therapy. Intravenous immunoglobulin for 5 days followed by a high dose of methylprednisolone were also administered. The patient was successfully discharged from the intensive care unit and remained in good condition after 2 months of follow-up.

CONCLUSIONS

mNGS served crucial roles in obtaining an etiological diagnosis, which suggested that screening for B. henselae should be considered in patients with HLH, especially those with a cat at home. In addition, the genetic defects were discovered to not only be present in primary HLH, but also in secondary HLH, even in the elderly.

Macrophage activation syndrome in adults: recent advances in pathophysiology, diagnosis and treatment

Haemophagocytic lymphohistiocytosis (HLH) is a hyperinflammatory syndrome, which if not promptly treated, can lead rapidly to critical illness and death. HLH is termed macrophage activation syndrome (MAS) when associated with rheumatic disease (where it is best characterized in systemic JIA) and secondary HLH (sHLH) when associated with other triggers including malignancy and infection. MAS/sHLH is rare and coupled with its mimicry of other conditions, is underrecognized. These inherent challenges can lead to diagnostic and management challenges in multiple medical specialties including haematology, infectious diseases, critical care and rheumatology. In this review we highlight the pathogenesis of MAS/sHLH including its underlying triggers, key clinical features and diagnostic challenges, prognostic factors and current treatments in adults.

Central Nervous System Involvement in 179 Chinese Children with Hemophagocytic Lymphohistiocytosis

Background:

Central nervous system (CNS) involvement is found in many patients with hemophagocytic lymphohistiocytosis (HLH). In this study, we mainly analyzed neurological symptoms, imaging findings, cerebrospinal fluid (CSF), and their relationship with outcomes of HLH children.

Methods:

Related data of 179 Chinese pediatric patients with HLH admitted to our center from January 2010 to December 2015 were analyzed retrospectively. Diagnosis and treatment were based on the HLH-2004 protocol. Two-tailed Chi-squared test was used to compare between different groups, and Kaplan-Meier survival curves were used to analyze the overall survival (OS) of patients with HLH.

Results:

In the present study, 21.2% (38/179) of total patients had neurological symptoms including seizure, irritability, somnolence, and unconsciousness. There were 80 (50.0%, excluding 19 patients without imaging data) patients with cranial imaging abnormalities. There were 14.7% (17/116, excluding 63 patients who did not accept lumbar puncture) of patients with abnormal CSF results. CNS involvement is defined as abnormalities in one or more of CNS symptoms, radiological findings, and CSF. Thus, 60.3% of them had CNS involvement. As for the prognosis, the median follow-up time was 3.2 years (17 lost to follow-up). The probable 3-year OS of children was higher without CNS involvement (86.0% ± 4.6%) than those with CNS involvement (68.9% ± 4.9%, hazard ratio [HR] = 2.286, P = 0.019). Among them, the probable 3-year OS of children without CNS symptoms was 76.0% ± 3.8%, higher than with CNS symptoms (59.5% ± 8.1%, HR = 2.147, P = 0.047). The 3-year OS of children with abnormal CSF was 64.7% ± 11.6%, compared with normal CSF (85.1% ± 3.7%, HR = 0.255, P = 0.038).

Conclusions:

HLH patients with CNS involvement might have worse outcomes compared with those without CNS involvement, and CNS symptoms and CSF changes are more important to access the prognosis than imaging abnormality.

Lymphoma associated hemophagocytic syndrome: A single-center retrospective study

To improve the understanding of lymphoma associated hemophagocytic syndrome (LAHS) and find an effective treatment for this fatal disease, 57 patients with LAHS were retrospectively reviewed. The most common histopathological type was extranodal natural killer (NK)/T-cell lymphoma, nasal type (ENKL) (45.61%). Patients with B-cell LAHS were significantly older (P<0.001), and exhibited a higher triglyceride level (P=0.012), lower serum ferritin level (P=0.014) and lower plasma Epstein-Barr virus DNA (P<0.001) compared with patients with T/NK-cell LAHS. The median survival time of all patients was 43 days, and patients with B-cell (n=14) and T/NK-cell (n=43) LAHS had a median survival time of 55 and 40 days, respectively (P=0.797). Compared with patients who were treated based on HLH-2004 protocols combined with multidrug chemotherapy, those without chemotherapy had a reduced prognosis (P=0.002). The patients that underwent hematopoietic stem cell transplantation (HSCT) following chemotherapy had a significantly improved overall survival (OS) compared with patients that did not undergo HSCT (P=0.001). Patients with B-cell LAHS treated with rituximab (P=0.015) and patients with ENKL treated with L-asparaginase/pegaspargase (L-asp/peg) (P=0.009) had an improved prognosis compared with patients not treated with these drugs. In the T/NK-cell LAHS group, patients treated with chemotherapy containing gemcitabine did not exhibit an improved OS compared with those not treated with gemcitabine (P=0.326). Furthermore, multivariate analysis demonstrated that long diagnosis time and poor performance status were independent prognosis factors for all patients with LAHS. The present study indicated that survival time does not differ between patients with B-cell LAHS and patients with T/NK-cell LAHS. Early diagnosis and appropriate immunochemotherapy plus HSCT are essential to achieve improved outcomes. The outcome of patients with B-cell LAHS may be significantly improved following treatment with rituximab. L-asp/peg-containing regimens are promising treatments for patients with NK/T-cell LAHS.

Macrophage Activation Syndrome

Hemophagocytic lymphohistiocytosis (HLH), or termed macrophage activation syndrome (MAS) when associated with rheumatic disorders, is a frequently fatal complication of infections, rheumatic disorders, and hematopoietic malignancies. Clinically, HLH/MAS is a life-threatening condition that is usually diagnosed among febrile hospitalized patients (children and adults) who commonly present with unremitting fever and a shock-like multiorgan dysfunction scenario. Laboratory studies reveal pancytopenia, elevated liver enzymes, elevated markers of inflammation (ESR, CRP), hyperferritinemia, and features of coagulopathy. In about 60% of cases, excess hemophagocytosis (macrophages/histiocytes engulfing other hematopoietic cell types) is noted on biopsy specimens from the bone marrow, liver, lymph nodes, and other organs. HLH/MAS has been hypothesized to occur when a threshold level of inflammation has been achieved, and genetic and environmental risk factors are believed to contribute to the hyperinflammatory state. A broad variety of infections, from viruses to fungi to bacteria, have been identified as triggers of HLH/MAS, either in isolation or in addition to an underlying inflammatory disease state. Certain infections, particularly by members of the herpesvirus family, are the most notorious triggers of HLH/MAS. Treatment for infection-triggered MAS requires therapy for both the underlying infection and dampening of the hyperactive immune response.

Proliferation through activation: hemophagocytic lymphohistiocytosis in hematologic malignancy

Hemophagocytic lymphohistiocytosis (HLH) is a syndrome of cytokine-driven immune activation. Cardinal features include fever, hemophagocytosis, hepatosplenomegaly, lymphocytic infiltration, and hypercytokinemia that result in multisystem organ dysfunction and failure. Familial HLH is genetically driven, whereas secondary HLH (SHL) is caused by drugs, autoimmune disease, infection, or cancer. SHL is associated with worse outcomes, with a median overall survival typically of less than 1 year. This reflects difficulty in both diagnostic accuracy and in establishing reliable treatments, especially in cases of malignancy-induced SHL, which have significantly worse outcomes. Malignancy-induced HLH is seen almost exclusively with hematologic malignancies, constituting 97% of cases in the literature over the past 2 years. In these situations, the native immune response driven by CD8 T cells produces an overabundance of T helper 1 cytokines, notably interferon-γ, tumor necrosis factor-α, and interleukin-6, which establish a positive feedback loop of inflammation, enhancing replication of hematologic malignancies while leaving the host immune system in disarray. In this paper, we present 2 case studies of secondary HLH driven by HM, followed by a review of the literature discussing the cytokines driving HLH, diagnostic criteria, and current treatments used or undergoing investigation.

Post-cytokine-release Salt Wasting as Inverse Tumor Lysis Syndrome in a Non-cerebral Natural Killer-cell Neoplasm

The pathogenesis of cerebral/renal salt-wasting syndrome remains unknown. We herein present a case of salt-wasting syndrome with a natural killer-cell neoplasm without cerebral invasion. A 78-year-old man with hemophagocytic syndrome received two cycles of chemotherapy that did not induce tumor lysis syndrome, but repeatedly caused polyuria and natriuresis. The expression of tumor necrosis factor-α in the neoplasm led us to hypothesize that an oncolysis-induced cytokine storm may have caused renal tubular damage and salt wasting. Our theory may explain the pathogenic mechanism of cerebral/renal salt-wasting syndrome associated with other entities, including cerebral disorders, owing to the elevation of cytokine levels after subarachnoid hemorrhage.

Understanding the spectrum of haemophagocytic lymphohistiocytosis: update on diagnostic challenges and therapeutic options

The cytokine storm syndrome 'haemophagocytic lymphohistiocytosis' (HLH) is an under-recognized hyperinflammatory disorder, causing high morbidity and mortality risk in children and adults. It can be subdivided into a primary, genetic form and a secondary, acquired form that complicates diverse infections, malignancies and autoimmune or autoinflammatory disorders. Both subtypes present with the same spectrum of non-specific symptoms, making accurate diagnosis and rapid treatment initiation challenging. In the last decade, increased awareness and international collaborative efforts fuelled a marked progress in diagnostic protocols and novel treatment strategies for HLH and new diagnostic guidelines are being tailored to specific secondary HLH subtypes. Therapy is gradually shifting its focus from overall immunosuppression towards targeting specific cytokines, cell types or signalling pathways underlying pathophysiology. Nevertheless, continued research efforts remain indispensable to customize therapy to individual patient needs.

High Pretreatment D-Dimer Levels Correlate with Adverse Clinical Features and Predict Poor Survival in Patients with Natural Killer/T-Cell Lymphoma

Pretreatment plasma D-dimer levels have been reported to predict survival in several types of malignancies. The aim of this study was to evaluate the prognostic value of D-dimer levels in patients with newly diagnosed natural killer/T-cell lymphoma (NKTCL). The cut-off value of D-dimer to predict survival was set as 1.2 μg/mL based on the receiver operating curve analysis. Patients with a D-dimer level ≥ 1.2 μg/mL had significantly more adverse clinical features, including poor performance status, advanced stage diseases, B symptoms, elevated serum lactic dehydrogenase levels, involvement of regional lymph nodes, more extranodal diseases, and higher International Prognostic Index and natural killer/T-cell lymphoma prognostic index scores. A D-dimer level ≥ 1.2 μg/mL was significantly associated with inferior 3-year overall survival (OS, 13.0 vs. 68.5%, P < 0.001). In the multivariate analysis, a D-dimer level ≥ 1.2 μg/mL remained an independent predictor for worse OS (HR: 3.13, 95% CI: 1.47-6.68, P = 0.003) after adjusting for other confounding prognostic factors. Among patients with Ann Arbor stage I-II diseases, those with a D-dimer level ≥ 1.2 μg/mL had a significantly worse survival than those with a D-dimer level < 1.2 μg/mL (3 year-OS: 76.2 vs. 22.2%, P < 0.001). Survival of early-stage patients with a high D-dimer level was similar to that of the advanced-stage patients. In conclusion, pretreatment plasma D-dimer level may serve as a simple but effective predictor of prognosis in patients with NKTCL.

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.

Splenectomy as a treatment for adults with relapsed hemophagocytic lymphohistiocytosis of unknown cause

Our aim was to evaluate the clinical value of splenectomy as a treatment for relapsed hemophagocytic lymphohistiocytosis (HLH) of unknown cause in adults. We retrospectively reviewed the clinical data from medical records of 19 adults with relapsed HLH of unknown cause treated with splenectomy in our institution from June 2007 to March 2014. To rule out possible underlying diseases, including infection, autoimmune disease, neoplasms, and primary HLH, the patients had undergone examinations including F18 fluoro-2-deoxyglucose positron emission tomography/computed tomography, HLH-associated gene defects, and lymph node biopsies. Twelve patients (63.2%) achieved partial responses (PR), whereas seven patients (36.8%) had no response (NR) prior to splenectomy. Infection and hemorrhage were the main complications of splenectomy. Eighteen cases were evaluable after follow-up. Seven cases with histopathologic diagnoses of lymphoma had received chemotherapy, four of whom had achieved complete responses (CR), one PR, and two NR. Maintenance treatment was ceased 2 or 3 months after splenectomy in the other 11 cases, five of whom had CR, four PR, and two NR. Eleven of 18 cases (61.1%) survived with a median follow-up of 25 months (range 3-79 months) for survivors. Twelve- and 36-month progression-free survival rates were 48 and 24%, respectively; 12- and 36-month overall survival rates were 57 and 25%, respectively. Median survival time was 22 months. Our results indicate splenectomy may be an effective means of diagnosis and treatment of relapsed HLH of unknown cause. Further study is required to establish the mechanism and value of splenectomy in this disease.

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

Hemophagocytic lymphohistiocytosis (HLH) comprises a group of life-threatening immune disorders classified into primary or secondary HLH. The former is caused by mutations in genes involved in granule-mediated cytotoxicity, the latter occurs in a context of infections, malignancies or autoimmune/autoinflammatory disorders. Both are characterized by systemic inflammation, severe cytokine storms and immune-mediated organ damage. Despite recent advances, the pathogenesis of HLH remains incompletely understood. Animal models resembling different subtypes of HLH are therefore of great value to study this disease and to uncover novel treatment strategies. In this review, all known animal models of HLH will be discussed, highlighting findings on cell types, cytokines and signaling pathways involved in disease pathogenesis and extrapolating therapeutic implications for the human situation.

Co-infections, inflammation and oncogenesis: future directions for EBV research

Epstein-Barr virus (EBV) is aetiologically linked to a wide range of human tumours. Some arise as accidents of the virus' lifestyle in its natural niche, the B lymphoid system; these include B-lymphoproliferative disease of the immunocompromised, Hodgkin Lymphoma, Burkitt Lymphoma and particular forms of diffuse large B cell lymphoma. Interestingly, HIV infection increases the incidence of each of these B cell malignancies, though by different degrees and for different reasons. Other EBV-associated tumours arise through rare viral entry into unnatural target tissues; these include all cases of nasal T/NK cell lymphoma and of undifferentiated nasopharyngeal carcinoma plus a small but significant subset of gastric carcinomas, a tumour type more generally associated with chronic Helicobacter pylori infection. Understanding EBV's involvement in the pathogenesis of these different malignancies is an important long-term goal. This article focuses on two overlapping, but relatively neglected, areas of research that could contribute to that goal. The first addresses the mechanisms whereby coincident infections with other pathogens increase the risk of EBV-positive malignancies, and takes as its paradigm the actions of holoendemic malaria and HIV infections as co-factors in Burkitt lymphomagenesis. The second widens the argument to include both infectious and non-infectious sources of chronic inflammation in the pathogenesis of EBV-positive tumours such as T/NK cell lymphoma, nasopharyngeal carcinoma and gastric carcinoma.

Natural killer/T-cell lymphoma-associated hemophagocytic syndrome: A case report

Natural killer (NK)/T-cell lymphoma-associated hemophagocytic syndrome (HPS) is a rare and fatal disease with no optimal treatment. The present study reports the clinical features, diagnosis and treatment process of three patients with relapsed NK/T-cell lymphoma-associated HPS. All of the patients were classified as Ann Arbor stage IV and presented with a poor performance status. Two patients were successfully treated with a pegaspargase-containing combination regimen and one patient succumbed due to serious complications. These cases indicate that for patients with a history of lymphoma, the diagnosis of HPS should be considered when patients present with progressive high fever, pancytopenia and liver dysfunction. Early identification and effective treatments, including pegaspargase-based regimens are essential for an enhanced prognosis.

Hemophagocytic lymphohistiocytosis: an update on diagnosis and pathogenesis

Hemophagocytic lymphohistiocytosis (HLH) is a frequently fatal and likely underdiagnosed disease involving a final common pathway of hypercytokinemia, which can result in end-organ damage and death. Although an early diagnosis is crucial to decrease mortality, the definitive diagnosis is often challenging because of the lack of specificity of currently accepted diagnostic criteria and the absence of confirmatory gold standards. Because of the wide range of laboratory assays involved in the diagnosis of HLH, practicing pathologists from a broad spectrum of clinical specialties need to be aware of the disease so that they may appropriately flag results and convey them to their clinical counterparts. Our article summarizes these new advances in the diagnosis of HLH and includes a review of clinical findings, updated understanding of the pathogenesis, and promising new testing methods.

EBV-Positive T/NK-Cell Lymphoproliferative Disease of Childhood

Background

Epstein-Barr virus (EBV)-associated hemophagocytic lymphohistiocytosis (HLH), EBV-positive systemic T-cell lymphoproliferative disease (STLPD) of childhood, and chronic active EBV (CAEBV) infection may develop after primary EBV infection. This study reviewed the clinicopathological spectrum of EBV-associated T- and natural killer (NK)-cell LPD, including STLPD and CAEBV infection, with an analysis of T-cell clonality.

Methods

Clinicopathological features of seven patients with EBV-associated HLH or STLPD and 12 patients with CAEBV infection were reviewed. Immunohistochemical staining and a T-cell receptor (TCR) gene rearrangement study were performed.

Results

STLPD and EBV-positive HLH showed significantly overlapping clinicopathological findings. One patient with STLPD and one patient with EBV-positive HLH demonstrated moderate to severe atypia of the infiltrating lymphocytes, whereas the remaining patients lacked significant atypia. Twelve patients had CAEBV infection, four of whom suffered mosquito-bite hypersensitivity, five showed NK lymphocytosis, and one suffered hydroa vacciniforme. Infiltrating lymphocytes were predominantly small and devoid of atypia. Hemophagocytic histiocytosis was found in seven of 11 patients. Monoclonality was detected in three (50%) of the six patients with successful TCR gene analysis.

Conclusions

EBV-positive HLH and STLPD share similar clinicopathological findings and may constitute a continuous spectrum of acute EBV-associated T- or NK-cell proliferative disorders. The distinction of EBV-positive T-cell LPD from EBV-positive HLH may be difficult during routine diagnoses because of the technical limitations of clonality assessment.

Pathobiology of Epstein-Barr virus-driven peripheral T-cell lymphomas

In the present review, the authors described the pathobiological features of Epstein-Barr virus (EBV)-driven T/natural killer cell-derived malignancies. These rare tumors appear to be quite heterogeneous with regard to both clinical and pathologic features. Nonetheless, some elements, especially regarding the possible role of EBV (ie, genomic predisposition, pathogenesis, pattern of latency), are similar, enforcing the concept of a causative role for the virus. In clinical practice, although definitely rare in Western countries, the tumors are not exceptional; thus, they should be taken into account in the differential diagnosis of T-lymphoproliferative disorders, also considering the need for extremely prompt intervention. The prognosis of such tumors is generally poor using current approaches. A better understanding of their molecular pathogenesis may lead to significant therapeutic improvements. For example, the nuclear factor-KB pathway and platelet-derived growth factor receptor inhibition may represent 2 options to be tested in clinical trials.

Primary cutaneous Epstein-Barr virus-associated T-cell lymphoproliferative disorder-2 cases with unusual, prolonged clinical course

Hydroa vacciniforme-like lymphoma and extranodal-type natural killer (NK)/T-cell lymphoma are prototypes of Epstein-Barr virus (EBV)-associated cutaneous T- or NK-cell lymphomas. Hydroa vacciniforme-like lymphoma with systemic spread and extranodal-type NK/T-cell lymphoma are characterized by aggressive clinical course. We describe 2 patients with primary cutaneous EBV-associated T-cell lymphomas who did not satisfy the criteria for well-defined entities and showed unusual, prolonged clinical course. They presented with skin ulcerations and mass lesions confined to the extremities without systemic involvement. Skin biopsies demonstrated dense superficial and deep perivascular and periappendageal lymphoid infiltrates expressing CD3 and CD8, but not CD56. The EBV genomes were found within the tumor cells, and monoclonal T-cell receptor gene rearrangement was present. We suggest that these cases represent a peculiar subtype of EBV+ cutaneous T-cell lymphoma, with a tendency to localize in the skin of the extremities and has an indolent clinical course.

NF-κB as a potential therapeutic target in myelodysplastic syndromes and acute myeloid leukemia

IMPORTANCE OF THE FIELD

The inactive NF-κB-inhibitor of NF-κB (IκB) complex is activated by stimuli including pro-inflammatory cytokines, mitogens, growth factors and stress-inducing agents. The release of NF-κB facilitates its translocation to the nucleus, where it promotes cell survival by initiating transcription of genes encoding stress-response enzymes, cell-adhesion molecules, pro-inflammatory cytokines and anti-apoptotic proteins. NF-κB and associated regulatory factors (IκB kinase subunits and bcl-3) are implicated in hematological and solid tumour malignancies. NF-κB appears to be involved in cell proliferation control, apoptosis control, angiogenesis promotion and possibly regulation of diffusion of metastases. There are several reports that inhibition of NF-κB as a therapeutic target may have a role in tumour cell death or growth inhibition.

AREA COVERED IN THIS REVIEW

We review data about inhibition of NF-κB in acute myeloid leukemia (AML) and myelodysplastic syndromes (MDS). We describe the molecular mechanisms underlying NF-κB deregulation in these haematological malignancies.

WHAT THE READER WILL GAIN

Constitutive activation of NF-κB in the nucleus has been reported in some varieties of MDS/AML. The in vitro and in vivo results of NF-κB inhibition in myeloid malignancies are highlighted.

TAKE HOME MESSAGE

NF-κB selective inhibitory drugs may be useful, either as single agents or associated with conventional chemotherapy.

What intensivists need to know about hemophagocytic syndrome: an underrecognized cause of death in adult intensive care units

Hemophagocytic syndrome, also known as hemophagocytic lymphohistiocytosis (HLH), is a rare and frequently fatal disorder caused by an uncontrollable and ineffective systemic immune response. Patients initially present with fever, cytopenia, and hepatosplenomegaly, and subsequently develop multiorgan failure (MOF). Hemophagocytosis can be found on biopsy specimen but is not required. Acquired forms of HLH can occur in apparently healthy adults, while children present more often with an inherited form of the disease. Since HLH often presents with sepsis-like symptoms and organ dysfunction, patients are usually treated for presumed sepsis, which inevitably leads to delayed diagnosis and treatment. Intensivists need to have a low threshold for suspecting this disorder when previously healthy individuals present with a fulminant sepsis-like syndrome, which are unresponsive to conventional treatment. We present 3 patients with HLH who were admitted to our adult medical intensive care unit (MICU) over a 2-year period with fatal outcomes and emphasize the diagnostic importance of markedly elevated serum ferritin levels and the need for tissue biopsy in making an accurate diagnosis in a timely manner.

Activation of T-cell receptor signaling in peripheral T-cell lymphoma cells plays an important role in the development of lymphoma-associated hemophagocytosis

Peripheral T-cell lymphoma (PTCL) is a biologically diverse lymphoid malignancy. The clinical aggressiveness associated with hemophagocytic syndrome (HS) is a characteristic of PTCL, being more distinctive in CD8(+) PTCL. However, the underlying mechanism of PTCL-associated HS has not yet been fully investigated. We newly established a novel IL-2-dependent CD8(+) PTCL lymphoma cell line (T8ML-1) from a patient with CD8(+) PTCL who suffered recurrent HS accompanying disease flare-up. Focusing on the lymphoma cell T-cell receptor (TCR), we examined the lymphoma cell functions responsible for such clinical manifestations. First, T8ML-1.1 in which endogenous TCR-α/β chains were silenced by siRNAs, and T8ML-1.2 in which endogenous TCR-α/β chains were replaced with HLA-A*24:02-restricted and WT1(235-243)-specific TCR-α/β, were established. T8ML-1 exerted phytohemagglutinin (PHA)-dependent cytotoxicity via granular exocytosis. Additionally, soluble factors produced by PHA-stimulated T8ML-1, which included INF-γ and TNF-α, but not by simple-cultured T8ML-1, caused human monocytes to exhibit erythrophagocytosis and thrombophagocytosis in vitro. PHA binding induced phosphorylation of CD3ζ chain. Furthermore, both cytotoxicity and hemophagocytosis were completely inhibited by T8ML-1.1, but eventually restored by T8ML-1.2. These data suggest that exogenous activation of TCR signaling in PTCL cells might play an important role in the formation of PTCL-associated HS.

Haemophagocytic lymphohistiocytosis complicating Hodgkin's lymphoma in an HIV-positive individual

We report the case of an HIV-positive man who presented with pyrexia of unknown origin. Histological specimens from an inguinal lymph node and liver biopsy gave a diagnosis of Epstein Barr virus (EBV)-positive Hodgkin's lymphoma and haemophagocytic lymphohistiocytosis (HLH), respectively. HLH is a condition characterized by proliferation of activated macrophages that phagocytose leukocytes, erythrocytes and platelets. Clinical features include splenomegaly, fever and pancytopenia, all of which have a wide differential diagnosis in HIV-positive patients. HLH can be caused by infections, malignancy, drugs or autoimmune conditions. There have been a number of reports of HLH in HIV-positive patients, and it can be seen at all stages of HIV infection. HIV, lymphomas, EBV infection and haemophagocytic syndrome have a complicated pathophysiology. Unfortunately, HLH in this setting has a particularly aggressive course, often with a poor outcome. This case highlights the need for awareness of the syndrome to ensure prompt diagnosis and instigation of appropriate treatment.

Microbiological findings and treatment of EBV-associated hemophagocytic lymphohistiocytosis: a case report

Epstein-Barr virus (EBV) is the major triggering factor for hemophagocytic syndrome or hemophagocytic lymphohistiocytosis (HLH). In patients with EBV-HLH, the EBV-infected T cells or natural killer cells are mostly mono- or oligoclonally proliferating, whereby hypercytokinemia plays a major role and causes hemophagocytosis, cellular damage, and dysfunction of various organs. This report describes the detection and treatment of EBV-associated HLH in the case of a 17-year-old male. Serum samples and skin swabs were tested for the presence of viral DNA using real-time PCR techniques. To confirm the molecular biological tests, electron microscopy was also performed. EBV DNA was detected with real-time PCR in both blood samples and skin swabs. The level of viral DNA constantly decreased during the applied therapy. The presence of the virus in the skin was confirmed by the appearance of herpes virus-like particles detected by electron microscopy in fluid taken from skin ulcerations. The results show that in terms of treatment, special therapeutic measures are required to control the cytokine storm generated by EBV and to suppress proliferating EBV genome-containing cells because the clinical course is often fulminate and results in a poor outcome. Therefore the potential of chemotherapy with a combination of steroids, etoposide, and cyclosporine to control HLH was assessed in the adolescent, who met the stringent diagnostic criteria for this reactive disorder of the mononuclear phagocyte system.

Vimentin-mediated signalling is required for IbeA+ E. coli K1 invasion of human brain microvascular endothelial cells

IbeA in meningitic Escherichia coli K1 strains has been described previously for its role in invasion of BMECs (brain microvascular endothelial cells). Vimentin was identified as an IbeA-binding protein on the surface of HBMECs (human BMECs). In the present study, we demonstrated that vimentin is a primary receptor required for IbeA+ E. coli K1-induced signalling and invasion of HBMECs, on the basis of the following observations. First, E44 (IbeA+ E. coli K1 strain) invasion was blocked by vimentin inhibitors (withaferin A and acrylamide), a recombinant protein containing the vimentin head domain and an antibody against the head domain respectively. Secondly, overexpression of GFP (green fluorescent protein)-vimentin and GFP-VDM (vimentin head domain deletion mutant) significantly increased and decreased bacterial invasion respectively. Thirdly, bacterial invasion was positively correlated with phosphorylation of vimentin at Ser82 by CaMKII (Ca2+/calmodulin-dependent protein kinase II) and IbeA+ E. coli-induced phosphorylation of ERK (extracellular-signal-regulated kinase). Blockage of CaMKII by KN93 and inhibition of ERK1/2 phosphorylation by PD098059 resulted in reduced IbeA+ E. coli invasion. Fourthly, IbeA+ E. coli and IbeA-coated beads induced the clustering of vimentin that was correlated with increased entry of bacteria and beads. Lastly, IbeA+ E. coli K1 invasion was inhibited by lipid-raft-disrupting agents (filipin and nystatin) and caveolin-1 siRNA (small interfering RNA), suggesting that caveolae/lipid rafts are signalling platforms for inducing IbeA-vimentin-mediated E. coli invasion of HBMECs. Taken together, the present studies suggest that a dynamic and function-related interaction between IbeA and its primary receptor vimentin at HBMEC membrane rafts leads to vimentin phosphorylation and ERK-mediated signalling, which modulate meningitic E. coli K1 invasion.

Comprehensive analyses and characterization of haemophagocytic lymphohistiocytosis in Vietnamese children

Haemophagocytic lymphohistiocytosis (HLH) is a fatal haematological disorder with diverse aetiology. This prospective study was undertaken to characterize HLH cases in Vietnamese children. Clinical and laboratory data, genetic analyses and outcome of the HLH patients were analysed. A total of 33 patients were enrolled from March 2007 to December 2008, with a median age of 3 years. Mutations of the SH2D1A (SAP) and PRF1 genes were detected in one patient, respectively. The virus association was high, up to 63.6% (21/33), including Epstein-Barr virus (19/33), cytomegalovirus (2/33) and dengue virus (2/33). Five patients had malignant lymphoma and two had autoimmune diseases. Twenty-eight patients were treated according to the HLH-2004 protocol. The first response rate was 64.3% (18/28), with an early death rate of 35.7% (10/28). High levels of interferon-gamma, interleukin-10, MIG and interferon-inducible protein-10 (IP-10) were associated with early mortality (P < 0.05). Reactivation among the responders was high (9/18) and the uneventful resolution was low (3/18) after a median follow-up of 35 weeks. In conclusion, the majority of HLH cases are associated with virus infections in Vietnamese children. Familial HLH is rare. The frequent reactivation and high mortality demands a more appropriate therapeutic regimen in tropical areas like Vietnam.

Haemophagocytic syndrome and HIV

PURPOSE OF REVIEW

Haemophagocytic syndrome (HPS) is a relatively rare complication of HIV infection but one that can take a particularly aggressive and potentially fatal course. The condition may be underrecognized due to the nonspecific nature of the clinical features. This review summarizes the pathogenesis, clinical and diagnostic features, common associations and current options in the management of HPS in the context of HIV infection, with the aim of increasing diagnostic awareness and facilitating early intervention.

RECENT FINDINGS

Our understanding of HPS is being increasingly informed by research into the molecular basis of the familial forms of the condition. The list of associated infections and neoplasms continues to lengthen, although the occurrence of HPS is increasingly recognized in the context of HIV infection alone, occasionally as its initial presentation in acute seroconversion. Diagnostic guidelines have recently been refined and attempts to adapt these to particular patient groups are ongoing. Management of HIV-associated HPS is adapted to the clinical context and may involve treatment of an underlying disorder or immunosuppressive therapy to reduce the activation of macrophages and T cells.

SUMMARY

The spectrum of HIV-related lymphoproliferative disorders continues to expand. Our understanding of their molecular and cellular basis and the role of infectious organisms in their development increasingly shapes and advances our clinical management of these complex conditions.