L-DEP regimen salvage therapy for paediatric patients with refractory Epstein-Barr virus-associated haemophagocytic lymphohistiocytosis

Epstein–Barr virus-associated haemophagocytic lymphohistiocytosis (EBV-HLH) is one of the most common subtypes of secondary HLH. However, more than 30% of patients do not respond to traditional treatment. Here, we investigated the efficacy and safety of the L-DEP regimen as a salvage therapy for paediatric refractory EBV-HLH. We retrospectively analysed 26 paediatric patients with refractory EBV-HLH who received the L-DEP regimen at Beijing Children’s Hospital from 1 January 2016 to 31 March 2019. Five of the patients achieved complete response (CR) and 11 achieved partial response (PR), indicating an overall response rate of 61·5% (CR + PR). Ten of the 16 patients who achieved CR or PR received allogenic haematopoietic stem cell transplantation (allo-HSCT), and seven were still alive at the last follow-up on 30 April 2020. Two of the 10 patients who did not respond were alive after allo-HSCT. Major side effects included increased amylase, bone marrow suppression and coagulation disorders, though these could be controlled by supportive therapy in most cases. Thus, we conclude that the L-DEP regimen is an effective and relatively safe salvage therapy for children with refractory EBV-HLH. This regimen also provides a bridge to allo-HSCT.     

Haemophagocytic lymphohistiocytosis and Epstein–Barr virus: a complex relationship with diverse origins,expression and outcomes

Epstein–Barr virus (EBV) is a ubiquitous herpesvirus with rare but severe potential for lymphoproliferative complications. EBV is associated with a variety of presentations of haemophagocytic lymphohistiocytosis (HLH). HLH is a life-threatening hyperinflammatory syndrome that can occur in patients with genetic defects associated with dysregulation of the immune response (familial HLH) or arise in patients with underlying infection or malignancy (non-familial or secondary HLH). EBV can both serve as the incidental trigger of familial HLH or as the driving factor in patients with selective inherited vulnerability (e.g. X-linked lymphoproliferative disease). Alternatively, acute infection can idiosyncratically cause non-neoplastic HLH in patients without inherited predisposition (i.e. secondary HLH), while EBV-associated T/natural killer (NK)-cell lymphoproliferative disorders and lymphomas can cause neoplasia-associated HLH. The present review will discern between EBV-associated familial and non-familial HLH and highlight diagnostic and therapeutic considerations. Non-familial EBV-associated HLH is a major diagnostic dilemma, as it represents a diverse spectrum of disease ranging from highly curable (non-neoplastic EBV-HLH) to indolent but incurable (chronic active EBV) to acutely fatal (systemic EBV-positive T-cell lymphoma of childhood). Increased clinical awareness and understanding of this rare and potentially devastating subset of EBV-related complications is desperately needed to improve survival for patients with neoplasia-associated HLH.     

Haemophagocytic lymphohistiocytosis associated with constitutional inversion of chromosome 9

Familial haemophagocytic lymphohistiocytosis (HLH) is considered an autosomal recessive disease, although the putative gene responsible for the disease has not yet been localized. Identification of the involved gene may elucidate the pathogenesis of the disease and is essential for prenatal testing in affected families. We present an infant with HLH and constitutional inversion 9 (p23q31) in cells from bone marrow, lymphocytes and fibroblasts. The parents had normal karyotypes. It may be speculated that one of the parents was a carrier of HLH and a de novo inversion occurred in chromosome 9 from the non-carrier parent. This would imply that the putative HLH-related gene is located at one of the two breakpoints on chromosome 9.     

Haemophagocytic lymphohistiocytosis: proposal of a diagnostic algorithm based on perforin expression

Haemophagocytic lymphohistiocytosis (HLH) is a rare, fatal disorder of early infancy. Mutations of the PRF1 gene have been identified in a subset of patients. However, the distinction between the different genetically determined and environmental subtypes of the disease remains a major issue to be solved. This may result in delayed or inappropriate application of bone marrow transplantation (BMT). We propose an algorithm that uses a combination of three rapid laboratory tests, i.e. perforin expression by peripheral lymphocytes, assessment of the behaviour of the 2B4 lymphocyte receptor and natural killer (NK) cell activity, to identify the different subgroups of HLH. In 19 patients diagnosed according to current criteria, we tested perforin expression, 2B4 receptor function and NK cell activity. PRF1 mutations were found in all seven patients showing absent perforin expression. In one male with abnormal behaviour of the 2B4 receptor, SH2D1A mutation confirmed the diagnosis of X-linked lymphoproliferative disease. Four patients with normal NK cell activity had evidence of associated infections. Of the seven with impaired NK cell activity, two had a probable genetically determined subtype of HLH and five appeared as sporadic, infection-associated cases. Improving the diagnostic approach may restrict the use of BMT, the only recognized curative treatment, to HLH patients with a documented poor prognosis while patients with milder disorders may be treated less intensively. Our flow chart could also lead to better selection of patients for specific gene analysis.     

Haemophagocytic lymphohistiocytosis in adults: a multicentre case series over 7 years

Haemophagocytic lymphohistiocytosis (HLH) is a syndrome of uncontrolled immune activation that has gained increasing attention over the past decade. Although classically known as a familial disorder of children caused by mutations that affect cytotoxic T‐cell function, an acquired form of HLH in adults is now widely recognized. This is often seen in the setting of malignancy, infection or rheumatological disorders. We performed a retrospective review across 3 tertiary care centres and identified 68 adults with HLH. The average age was 53 years (range 18–77 years) and 43 were male (63%). Underlying disorders included malignancy in 33 patients (49%), infection in 22 (33%), autoimmune disease in 19 (28%) and idiopathic HLH in 15 (22%). Patients were treated with disease‐specific therapy and immunomodulatory agents. After a median follow‐up of 32·2 months, 46 patients had died (69%). The median overall survival was 4 months (95% CI: 0·0–10·2 months). Patients with malignancy had a worse prognosis compared to those without (median survival 2·8 months versus 10·7 months, P = 0·007). HLH is a devastating disorder with a high mortality. Further research is needed to improve treatment and outcomes.     

Hyper-interleukin (IL)-6-naemia in haemophagocytic lymphohistiocytosis

Clinical features in patients with haemophagocytic lymphohistiocytosis (HLH) have been demonstrated to be characterized by hypercytokinaemia. Previously, we reported the impact of high serum levels of interferon (IFN)-gamma and soluble IL-2 receptor (sIL-2R) on patient outcome; however, it was not known if serum levels of interleukin (IL)-6 also could be a prognostic factor. In a study during the active phase of disease in 25 cases of HLH in children and young adults (median age 3 years, range 0.1–23 years), we noted 12 cases which showed serum IL-6 >100 (normal <4.0) pg/ml. Five of these cases showed hyper-IL-6-naemia alone without hyper-IFN-gamma-naemia (group A) whereas seven cases showed both hyper-IL-6- and IFN-gamma-naemia (group B). Patient outcome did not differ between the patients with IL-6 >100 pg/ml and those with IL-6 <100 pg/ml, suggesting that high serum concentrations of IL-6 alone do not necessarily indicate poor prognosis in patients with HLH. Among the cases with hyper-IL-6-naemia (>100 pg/ml), underlying disorders causing haemophagocytosis were found to be different between groups A and B.     

Haemophagocytic lymphohistiocytosis: experience at two U.K. centres

Summary Haemophagocytic lymphohistiocytosis (HLH) is a rare disorder of inappropriate macrophage activation. Both familial and sporadic forms, which may be infection-associated, are recognized. Between 1985 and 1991 we treated 23 cases of HLH (12 male, 11 female). There were eight familial cases, defined by a previously affected sibling and/or history of consanguinity, age 3 d to 15 months at presentation. The age of the remaining 15 cases varied from 1 month to 9.5 years. A potential viral trigger was identified in four cases (EBV, two; parvovirus B19, one; echovirus II, one) including one familial case. Six of eight (75%) patients who received supportive care alone, including all four familial cases, died within 6 months of presentation. Both long-term survivors in this group presented at an older age (7.5 and 8 years) and had proven or suspected virus-associated HLH. 15 patients were treated with etoposide (150–250 mg/m² days 1–3 every 21 d) and methylprednisolone; 10 patients received intrathecal methotrexate in addition. In nine (60%) of these cases a complete (six) or partial (three) response was achieved, though one child suffered a fatal 'tumour lysis' syndrome. Overall mortality in the treated group was 66.6%, being highest (75%) in patients under 2 years at presentation compared to 33% in those over 2 years. Two of three familial and one of five sporadic cases relapsed and died 3 d to 20 months from diagnosis. Only one familial case survives at follow-up of 11 months. Of the five remaining survivors, two received allogeneic bone marrow transplantation (one matched related, one haploidentical) and are alive at 11 and 29 months. Three cases aged 2.5, 7.5 and 9.5 years remain in remission at 11, 20 and 25 months respectively. The high mortality of HLH supports a role for allogeneic BMT in selected cases, particularly those with a familial basis or under 2 years at presentation.     

Involvement of interferon-γ and macrophage colony-stimulating factor in pathogenesis of haemophagocytic lymphohistiocytosis in adults

Summary We investigated the role of monocyte/macrophage-activating cytokines in pathogenesis of haemophagocytic lymphohistiocytosis (HLH) in 21 adult patients. Sera from patients with active HLH contained extremely high levels of macrophage colony-stimulating factor (M-CSF) and of interferon-γ (IFN-γ). These levels returned to almost normal during remission. Neither interleukin-4 nor granulocyte/macrophage colony-stimulating factor could be detected. Active HLH sera also contained high concentrations of inflammatory monokines, such as interleukin-6 (IL-6) and tumour necrosis factor-α (TNF-α). Serum concentrations of soluble CD8 and soluble interleukin-2 receptor were extremely high during active HLH, and returned to virtually normal levels during remission. Circulating CD2⁺ T-cells obtained from patients with active HLH spontaneously secreted M-CSF and IFN-γ in vitro , whereas circulating monocytes did not produce detectable levels of both M-CSF and IFN-γ, but produced high levels of IL-6 and TNF-α. These findings suggest that IFN-γ and M-CSF at least partly from T-cells, such as CD8⁺ T-cells, might contribute to activation of monocytes or histiocytes, resulting in the up-regulated monokine production and haemophago-cytosis in HLH.     

Haemophagocytic syndrome associated with hepatitis‐B virus infection responding to etoposide

Haemophagocytic syndrome (HPS) secondary to viral infections usually has a variable course and can be life‐threatening. We report a 53‐year‐old male patient who presented with fever, hepatosplenomegaly and pancytopenia. He had deranged liver function, abnormal clotting and markedly elevated serum ferritin. Bone marrow biopsy showed prominent haemophagocytosis. The patient was investigated thoroughly and found to have evidence of chronic hepatitis B‐virus (HBV) infection by serological tests and liver biopsy. Other conditions associated with HPS such as lymphoma, malignancy and other viral or bacterial infections were not present. The patient did not respond to steroids, intravenous immunoglobulins or cyclosporin but responded to etoposide and became apyrexial. He also became HBV negative on lamivudine. The patient died of infection later on but there was no evidence of recurrence of HPS. To the best of our knowledge this is the first case report of HPS associated with isolated HBV infection.     

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-γ, 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 lymphohistiocytosis in association with granular lymphocyte proliferative disorders in early childhood: characteristic bone marrow morphology

Five paediatric cases of haemophagocytic lymphohistiocytosis (HLH) which showed proliferation of granular atypical lymphocytoid cells in bone marrow are reported. All cases were girls aged 8 months to 4 years who had marked hepatosplenomegaly. Marker analysis on peripheral blood mononuclear cells revealed an increase in the CD3⁺HLADR⁺ subset in three cases and the CD³⁻CD56⁺ subset in one case. An Epstein-Barr virus genome was detected in three cases, and monoclonality was confirmed in two cases. A characteristic morphology of large granular lymphocytes (LGL) was identified, with elongated bizarre features that resembled horsetail-, tadpole-, cucumber- or shooting star-type configurations on the bone marrow smear. Serum concentrations of soluble interleukin-2 receptor and interferon-gamma were elevated in all cases. All five cases required multi-agent chemotherapy which resulted in two complete remissions, two partial remissions and one no response. Refinement of treatment is required for these paediatric GLPD cases which probably comprise a specific high-risk subgroup among secondary HLH patients which had previously escaped notice.     

Haemophagocytic lymphohistiocytosis in X-linked severe combined immunodeficiency

Haemophagocytic lymphohistiocytosis (HLH) is characterized by destruction of haematopoietic elements, and is associated with a variety of manifestations including immune abnormalities. We describe an infant with HLH who had no evidence of infection or malignancy. He had markedly reduced natural killer (NK) and T-cell numbers and mitogen responses, consistent with severe combined immune deficiency. Western blot and flow cytometry analyses revealed an absence of interleukin (IL)-2 receptor gamma (gamma common) chain expression and a transition (C --> T) at nucleotide 684 in the gamma common gene. This novel case highlights the need for a thorough evaluation of immunological phenotype and genotype in patients with HLH.     

Clinicopathological spectrum of haemophagocytic syndrome in Epstein-Barr virus-associated peripheral T-cell lymphoma

Haemophagocytic syndrome (HS) is frequently observed in Epstein-Barr virus-associated peripheral T-cell lymphoma (EBV-PTCL) and represents a major cause of death. In this communication we have further analysed the spectrum of HS in 12 patients with EBV-PTCL. The patients could be divided into three groups according to the time of onset of HS during the clinical course of PTCL. Group I patients (four cases) had HS as the initial clinical manifestation. All four patients were initially suspected to have malignant histiocytosis (MH) but a MH-like PTCL was later diagnosed. Group II patients (six cases) developed HS at the time of lymphoma relapse. Four of them belonged to the angioinvasive type PTCL. Group III patients (two cases) developed HS at clinical remission; both were angioinvasive type PTCL. Nine patients had serological evidence suggesting active EBV infection. The clinical course after the onset of HS was generally fulminant in each group with a median survival of only 44 d despite combination chemotherapy and/or empirical therapy with high-dose immunoglobulin and corticosteroids in six patients. In conclusion, HS represents a severe complication of EBV-PTCL. Although most patients develop HS at a time of active lymphoma, the syndrome may occur when the lymphoma is in remission. Because of the poor outcome, early diagnosis and a new modality of treatment for HS associated with EBV-PTCL should be pursued in future.     

Requirement for etoposide in the initial treatment of Epstein-Barr virus–associated haemophagocytic lymphohistiocytosis

Haemophagocytic lymphohistiocytosis (HLH) is a severe, even fatal, inflammatory condition. Epstein–Barr virus (EBV) infection-associated HLH (EBV-HLH) is one of the most common types of secondary HLH. Etoposide is a key drug in HLH-94/04 regimen. We sought to identify the importance of etoposide in the initial treatment of EBV-HLH. Ninety-three patients with EBV-HLH of all ages admitted to our centre in 2017 were divided into two groups according to whether the initial treatment contained etoposide or not. The survival of the group whose initial therapy included etoposide (Group 1, 52 patients; 6-month survival rate 0·769) was significantly better than that of the group whose initial therapy did not include etoposide (Group 2, 41 patients; 6-month survival rate 0·269) (P < 0·001). In patients aged <18 years old, the survival of Group 1 patients was not significantly better than that of Group 2 patients (P = 0·447), in contrast to patients aged ≥18 years, where the survival of Group1 patients was significantly better than that of Group 2 patients (P < 0·001). We concluded that including etoposide in the initial treatment of EBV-HLH patients can improve their prognosis, especially adult patients. This may be because that adult patients are recognized as “higher risk” patients.     

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.     

Frequency and spectrum of central nervous system involvement in 193 children with haemophagocytic lymphohistiocytosis

Haemophagocytic lymphohistiocytosis (HLH) may cause meningoencephalitis and significant neurological sequelae. We examined the relationship between neurological symptoms and cerebrospinal fluid (CSF) at diagnosis, and long-term outcome, in all children enroled in the HLH-94-study prior to July 1, 2003, for whom information on CSF at diagnosis was available (n = 193). Patients were divided into four groups: (i) normal CSF (cells/protein) and no neurological symptoms (n = 71); (ii) normal CSF but neurological symptoms (n = 21); (iii) abnormal CSF but no symptoms (n = 50); and (iv) abnormal CSF with neurological symptoms (n = 51). At diagnosis, neurological symptoms were reported in 72/193 (37%) (seizures = 23); abnormal CSF in 101/193 (52%), and either or both in 122/193 (63%). Altogether 16/107 (15%) survivors had neurological sequelae at follow-up (median 5.3 years). Multivariate hazard ratios (HR) for mortality were 0.98 [95% confidence interval (CI) = 0.42-2.31], 1.52 (0.82-2.82) and 2.05 (1.13-3.72) for groups 2-4, compared with group 1. Moreover, sequelae were more frequent in group 4 (7/21, 33%) compared to groups 1-3 (9/86, 10%) (P = 0.015). Patients with abnormal CSF at diagnosis had significantly increased mortality [HR = 1.78 (95% CI = 1.08-2.92), P = 0.023]. Thus, a substantial proportion of HLH survivors suffer neurological sequelae, and children with abnormal CSF have increased risk of mortality and neurological sequelae. Prompt treatment of HLH at onset or relapse may reduce these complications.