Laboratory parameters identify familial haemophagocytic lymphohistiocytosis from other forms of paediatric haemophagocytosis

Congenital Echovirus 11 Infection in a Neonate

Neonates infected with enterovirus in utero would be fulminant at birth or develop symptoms within a few days. Echovirus 11 causes life-threatening hepatic necrosis with coagulopathy and adrenal hemorrhagic necrosis. The prognosis depends on the enterovirus serotype and the absence of serotype-specific maternal antibodies at the time of delivery. We describe a fatal neonatal case of congenital echovirus 11 infection.

A retrospective survey of patients who discontinued participation in the JPLSG HLH-2004 clinical trial

Although clinical trials have reported an improvement in the prognosis of hemophagocytic lymphohistiocytosis (HLH), current treatment outcomes are unsatisfactory, especially in severe cases. Most clinical trial patients with severe disease discontinue participation due to complications associated with HLH or treatment-related toxicity. A retrospective survey of patients who discontinued participation in the JPLSG HLH-2004 clinical trial was conducted to review the detailed course of these cases to optimize HLH treatment and supportive care. Findings in these patients were compared with those of 45 patients who completed the protocol treatment. The 3 year overall survival rate of patients who completed treatment was 86.7%, versus 50.7% for those who did not complete treatment. Incidence of serious adverse events, such as infections, coagulopathy, and posterior reversible encephalopathy syndrome, during the initial 8 weeks of treatment was much higher in patients who did not complete treatment than in patients who completed treatment. To improve overall outcomes of patients with HLH, it is important to not only optimize HLH-directed therapy but also provide appropriate supportive care.

Case report: Cerebellar swelling and hydrocephalus in familial hemophagocytic lymphohistiocytosis

Familial hemophagocytic lymphohistiocytosis (FHL) is a severe inborn error of immunity caused by a genetic defect that impairs the function of cytotoxic T and NK cells. There are only a few reported cases of FHL with diffuse swelling of the cerebellum and obstructive hydrocephalus. We report a case of FHL3 with neurological symptoms associated with cerebellar swelling and obstructive hydrocephalus. A male patient was hospitalized several times due to fever and decreased feeding, hepatosplenomegaly, and cytopenia since the first month of life. At 7 months of age, disturbance of consciousness was seen. Brain magnetic resonance imaging revealed signal intensity in the bilateral cerebellar hemispheres, diffusely increased periventricular white matter, and ventriculomegaly. Although he was treated with methylprednisolone pulse therapy, he was unresponsive to the treatment. He was then transferred to a local hospital after tracheotomy but died. Targeted clinical sequencing revealed a homozygous splice-site mutation in UNC13D. Pediatric hemophagocytic lymphohistiocytosis (HLH) includes some cases of central nervous symptom (CNS)-isolated HLH or CNS HLH preceding systemic lesions, which often do not initially meet the diagnostic criteria for FHL. Patients with FHL initiated by cerebellar symptoms may present with an atypical clinical course for HLH, leading to delayed diagnosis and poor outcomes. Despite the usefulness of a combination of a high percentage of lymphocytes in the peripheral leukocytes, a low lactate dehydrogenase level, and a high sIL-2R/ferritin ratio for identifying FHL, the diagnosis may be missed due to the absence of these results. Presymptomatic diagnosis of FHL by screening of newborns and subsequent early treatment of patients with a predicted poor prognosis may contribute to better outcomes.

Virus-triggered secondary hemophagocytic lymphohistiocytosis

Primary (familial/hereditary) and secondary (non-familial/hereditary) hemophagocytic lymphohistiocytosis (HLH) are hyperinflammatory and hypercytokinemic syndromes. Secondary HLH includes infection- (eg viral/bacterial/fungal/parasitic) and non-infection- (eg collagen disease or malignancy) related diseases. Viral HLH is the major type among all age groups. Secondary viral HLH and primary HLH must be differentiated carefully because primary HLH can be associated with viral infection(s), and the outcome is dismal without a timely diagnosis and hematopoietic stem cell transplantation (HSCT). Epstein-Barr virus (EBV)-related HLH (EBV-HLH) is the most common type of viral HLH in childhood. For non-EBV-HLH, appropriate treatment of viral infection, followed by immunomodulatory agent(s) such as corticosteroids, intravenous immunoglobulin or cyclosporine A, is usually successful; however, recent SARS-CoV-2-related HLH may become life-threatening. EBV-HLH may occur heterogeneously associated with the primary infection, with chronic active EBV infection or with underlying primary HLH. Although immunomodulatory agent(s) are effective in the majority of EBV-HLH cases, management differs from that of non-EBV-HLH because severe and refractory cases may require etoposide-containing HLH-1994/2004 regimens or other experimental agents. The novel agent, emapalumab (an anti-IFN-γ monoclonal antibody) can be used to treat EBV-HLH cases to avoid the risk of secondary malignancy due to etoposide. Finally, HSCT is required for refractory EBV-HLH cases and can also be curative in some other cases.

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

Objectives

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

Methods

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

Results

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

Conclusion

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

Malignancy-associated hemophagocytic lymphohistiocytosis in children: a 10-year experience of a single pediatric hematology center

Objective: Malignancy-associated hemophagocytic lymphohistiocytosis (M-HLH) in children is a relatively rare but life-threatening secondary hemophagocytic lymphohistiocytosis (sHLH). Until now, only a limited number of cases regarding children with M-HLH has been reported. Methods: We conducted a retrospective study of 27 children with M-HLH, who admitted to our center between July 2007 and October 2019. The clinical data and laboratory data were analyzed. Results: The median age of the children with M-HLH was 7 years. Underlying diseases included myeloid malignancy (n = 6), lymphoid malignancy (n = 18) and unknown type lymphoma (n = 3). The one-year mortality rate was 56%. All patients had persistent fever. The clinical manifestations included hepatomegaly (89%), splenomegaly (67%) and central nervous system symptoms (56%). Thirteen children (48%) had Epstein-Barr virus (EBV) infection. No significant differences were observed between EBV-positive and negative M-HLH patients in terms of most clinical indicators. However, EBV-positive M-HLH patients showed prolonged activated partial thromboplastin time (APTT) and more hemophagocytosis in the bone marrow (BM) in contrast to EBV-negative patients. Eighteen patients (67%) received the HLH-94/04 regimen as the initial treatment. There were no significant differences in the overall survival (OS) between EBV-positive and negative patients. Patients with prolonged APTT had a significantly poorer OS than other patients (p = 0.012). Conclusions: The M-HLH children with EBV infection are more likely to have prolonged APTT and more hemophagocytosis in BM. The M-HLH children had a poor prognosis, especially those with prolonged APTT.

Three Consecutive Cases of Familial Hemophagocytic Lymphohistiocytosis, Including a Case Due to Maternal Uniparental Disomy

We have experienced 3 consecutive cases of familial hemophagocytic lymphohistiocytosis (FHL). All affected infants had mutations in exon 3 of the perforin gene. The first had a homozygous mutation, c.1168C>T (p.R390*), caused by maternal uniparental isodisomy. The second and third had compound heterozygous mutations: c.781G>A (p.E261K) and c.1491T>A (p.C497*); c.1724G>T (p.C242G) and p.R390*, respectively. FHL is very rare in Northern Japan but should be suspected if infants exhibit prolonged fever. This is the first report of a relationship of p.R390* with FHL caused by uniparental isodisomy, and the second reported case of FHL type 2 with this form of inheritance.

Fetal presentation of congenital dyserythropoietic anemia type 1 with novel compound heterozygous CDAN1 mutations

The congenital dyserythropoietic anemias are a heterogeneous group of disorders characterized by anemia and ineffective erythropoiesis. Congenital dyserythropoietic anemia type I (CDA1) can present in utero with hydrops fetalis, but more often it presents in childhood or adulthood with moderate macrocytic anemia, jaundice, and progressive iron-overload. CDA1 is inherited in an autosomal recessive manner, with biallelic pathogenic variants in CDAN1 or C15orf41. This case report documents a severe fetal presentation of CDA1 where we identified two novel compound heterozygous mutations in CDAN1 and describes the associated pathologic findings and levels of iron-regulatory proteins hepcidin, erythroferrone, and GDF15.

Interdisciplinary care of a neonate with haemophagocytic lymphohistiocytosis

Haemophagocytic lymphohistiocytosis (HLH) is a rare condition not commonly observed in neonatal units. It poses a challenge to neonatal staff to source expertise and information when diagnosing and treating patients with this condition. This article uses a case study of a neonate with HLH to analyse interdisciplinary team dynamics in hospital and explore how teams can effectively share knowledge and learn from each other when treating patients with rare and complex conditions.

Clinical utility of soluble interleukin-2 receptor in hemophagocytic syndromes: a systematic scoping review

The serum-soluble interleukin-2 receptor (sIL-2r) level is considered an important diagnostic test and disease marker in hemophagocytic syndromes/hemophagocytic lymphohistiocytosis (HPS/HLH). However, this cytokine receptor is rarely measured in clinical practice and has been excluded from recent diagnostic/classification criteria such as the HScore and macrophage activation syndrome (MAS) 16. We performed a systematic scoping review of 64 articles (1975-2016) examining the clinical utility of sIL-2r in HPS/HLH. Twenty-two articles describe sIL-2r as a sensitive diagnostic marker for HLH, but only three distinct datasets actually address sensitivity. The original HLH-2004 Guidelines reported sensitivity of 93% and specificity of 100% for sIL-2r ≥ 2400, based on a pediatric dataset (n = 152) which is published for the first time in this review. Two pediatric studies reported sensitivity of 89% for sIL-2r ≥ 2400 in diagnosis of MAS complicating juvenile idiopathic arthritis (JIA) (n = 27) and 88% for secondary HLH in acute liver failure (n = 9). Twenty articles described sIL-2r as a dynamic marker of disease activity that falls with response to treatment, and 15 described high initial sIL-2r levels >10,000 U/mL as a poor prognostic marker. The ability of sIL-2r to distinguish between subtypes of HPS/HLH was inconsistent. This review confirms the importance of soluble IL-2r as a diagnostic and disease marker in HPS/HLH, but also reveals the need for more primary data about its performance characteristics, particularly in adults. More emphasis should be made in including this simple, inexpensive test in clinical practice and studies of HPS/HLH.

Similar but not the same: Differential diagnosis of HLH and sepsis

Differential diagnosis of hemophagocytic lymphohistiocytosis (HLH; hemophagocytic syndrome) and sepsis is critically important because the life-saving aggressive immunosuppressive treatment, required in the effective HLH therapy, is absent in sepsis guidelines. Moreover, HLH may be complicated by sepsis. Hyperinflammation, present in both states, gives an overlapping clinical picture including fever and performance status deterioration. The aim of this review is to provide aid in this challenging diagnostic process. Analysis of clinical features and laboratory results in multiple groups of patients (both adult and pediatric) with either HLH or sepsis allows to propose criteria differentiating these two conditions. The diagnosis of HLH is supported by hyperferritinemia, splenomegaly, marked cytopenias, hypofibrinogenemia, low CRP, characteristic cytokine profile and, only in adults, hypertriglyceridemia. In the presence of these parameters (especially the most characteristic hyperferritinemia), the other HLH criteria should be assessed. Genetic analyses can reveal familial HLH. Hemophagocytosis is neither specific nor sensitive for HLH.

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.

Comparison of Th1/Th2 cytokine profiles between primary and secondary haemophagocytic lymphohistiocytosis

Background

Haemophagocytic lymphohistiocytosis (HLH) is a life-threatening disorder of immune regulation, and HLH patients with mutations in genes including PRF1, UNC13D, STX11, STXBP2, SH2D1A, XIAP, and ITK were reported to be primary HLH. Due to the different treatment options, the differentiation between primary and secondary HLH is critical. Our previous studies have showed that a Th1/Th2 cytokine profile is diagnostic for HLH, yet the cytokine profiles between primary and secondary HLH have not been compared. The aim of the study was to test whether the Th1/Th2 cytokine profile could be used as a tool to differentiate between primary and secondary HLH.

Methods

A total of 45 hospitalized Chinese children with HLH during the period of February 2010 through September 2012 were enrolled in the study. Fifty healthy children were enrolled as controls. Primary HLH related genes were sequenced using genomic DNA samples. The Th1/Th2 cytokine levels including interferon-γ (IFN-γ), tumor necrosis factor-alpha (TNF-α), interleukin (IL)-10, IL-6, IL-4 and IL-2 were quantitatively determined by cytometric bead assay techniques.

Results

Primary HLH group (n = 4) included one patient with biallelic heterozygous mutations in PRF1 gene, and three patients with hemizygous mutation in SH2D1A gene. Based on the available genetic data, the other 41 patients were classified into the secondary HLH group. When compared the cytokine levels between the two groups, IL-4 level in primary-HLH was significantly lower than that in secondary HLH (P = 0.025), while IFN-γ level in primary HLH had a tendency of statistically lower than that in secondary HLH (P = 0.051). Area under receiver operating characteristic (ROC) curves of IL-4 and IFN-γ, IL-10, TNF-α, IL-2, and IL-6 levels were 0.841, 0.799, 0.506, 0.494, 0.457, and 0.250, respectively. ROC curves showed that 1.7 pg/ml of IL-4 had sensitivity and specificity for differentiation between primary and secondary HLH as 70.7 and 100.0 %, while 433.9 pg/ml of IFN-γ had sensitivity and specificity as 51.2 and 100.0 %, respectively.

Conclusions

HLH patients with lower IL-4 and IFN-γ levels have higher possibility to be primary HLH. The cytokine profile may be used as an additional tool for the quick differential diagnosis between primary and secondary HLH.

Electronic supplementary material

The online version of this article (doi:10.1186/s13052-016-0262-7) contains supplementary material, which is available to authorized users.

Mouse Cytomegalovirus Infection in BALB/c Mice Resembles Virus-Associated Secondary Hemophagocytic Lymphohistiocytosis and Shows a Pathogenesis Distinct from Primary Hemophagocytic Lymphohistiocytosis

Hemophagocytic lymphohistiocytosis (HLH) is a life-threatening immunological disorder that is characterized by systemic inflammation, widespread organ damage, and hypercytokinemia. Primary HLH is caused by mutations in granule-mediated cytotoxicity, whereas secondary HLH occurs, without a known genetic background, in a context of infections, malignancies, or autoimmune and autoinflammatory disorders. Clinical manifestations of both HLH subtypes are often precipitated by a viral infection, predominantly with Herpesviridae. Exploiting this knowledge, we established an animal model of virus-associated secondary HLH by infecting immunocompetent wild-type mice with the β-herpesvirus murine CMV. C57BL/6 mice developed a mild inflammatory phenotype, whereas BALB/c mice displayed the clinicopathologic features of HLH, as set forth in the Histiocyte Society diagnostic guidelines: fever, cytopenia, hemophagocytosis, hyperferritinemia, and elevated serum levels of soluble CD25. BALB/c mice also developed lymphadenopathy, liver dysfunction, and decreased NK cell numbers. Lymphoid and myeloid cells were in a hyperactivated state. Nonetheless, depletion of CD8(+) T cells could not inhibit or cure the HLH-like syndrome, highlighting a first dissimilarity from mouse models of primary HLH. Immune cell hyperactivation in BALB/c mice was accompanied by a cytokine storm. Notably, plasma levels of IFN-γ, a key pathogenic cytokine in models of primary HLH, were the highest. Nevertheless, murine CMV-infected IFN-γ-deficient mice still developed the aforementioned HLH-like symptoms. In fact, IFN-γ-deficient mice displayed a more complete spectrum of HLH, including splenomegaly, coagulopathy, and decreased NK cell cytotoxicity, indicating a regulatory role for IFN-γ in the pathogenesis of virus-associated secondary HLH as opposed to its central pathogenic role in primary HLH.