Genetic features of late onset primary hemophagocytic lymphohistiocytosis in adolescence or adulthood. PLoS One. 2014;9:e107386. [PMID: 25233452 PMCID: PMC4169386 DOI: 10.1371/journal.pone.0107386]

Hemophagocytic Lymphohistiocytosis in Adolescents and Young Adults: Genetic Predisposition and Secondary Disease

Hemophagocytic lymphohistiocytosis (HLH) is a disorder of impaired immune regulation resulting in hyperinflammation that is ultimately fatal if not treated. HLH is categorized into familial disease, caused by genetic mutations affecting the function of cytotoxic T lymphocytes and natural killer cells, and secondary disease, triggered by infections, malignancies, rheumatologic disorders, or immune deficiency. Adolescent and young adults with HLH represent a unique population with specific diagnostic challenges. Here we review the diagnostic criteria, possible etiologies, pathophysiology, and management of HLH with focus on the adolescent population.

Case report: Hemophagocytic lymphohistiocytosis complicated by multiple organ dysfunction syndrome following aseptic encephalitis

Hemophagocytic lymphohistiocytosis (HLH) is a rare but potentially life-threatening condition caused by excessive immune activation. Secondary HLH is usually triggered by infection, most often from viral infection or malignancy. Here, we present a case of secondary HLH, complicated by multiple organ dysfunction syndrome triggered by critical aseptic encephalitis. A 27-year-old man without any underlying disease presented to our hospital with fever, disturbance of consciousness, and generalized seizures. The patient was diagnosed with aseptic encephalitis with super-refractory status epilepticus. Although antiseizure medications and immunoglobulins were administered, the patient developed multiple organ dysfunction syndrome. HLH was later diagnosed based on hypertriglyceridemia, hyperferritinemia, splenomegaly, cytopenia, and phagocytosis of nucleated cells, as shown by a blood smear of bone marrow aspiration. Treatment with pulse steroid therapy and plasmapheresis was initiated rather than chemotherapy because of the patient's critical condition. However, the patient died of profound shock and multiple organ failure. Diagnosis of HLH is challenging in patients with severe infections because of similar clinical manifestations and laboratory findings. The early recognition of HLH provides patients with the opportunity to receive appropriate treatment, which can lead to increased survival and remission rates.

Diagnosis and Management of Adult Malignancy-Associated Hemophagocytic Lymphohistiocytosis

Hemophagocytic lymphohistiocytosis (HLH) is a syndrome of severe, dysregulated inflammation driven by the inability of T cells to clear an antigenic target. When associated with malignancy (mHLH), the HLH syndrome is typically associated with extremely poor survival. Here, we review the diagnosis of secondary HLH (sHLH) syndromes in adults, with emphasis on the appropriate workup and treatment of mHLH. At present, the management of HLH in adults, including most forms of mHLH, is based on the use of corticosteroids and etoposide following the HLH-94 regimen. In some cases, this therapeutic approach may be cohesively incorporated into malignancy-directed therapy, while in other cases, the decision about whether to treat HLH prior to initiating other therapies may be more complicated. Recent studies exploring the efficacy of other agents in HLH, in particular ruxolitinib, offer hope for better outcomes in the management of mHLH. Considerations for the management of lymphoma-associated mHLH, as well as other forms of mHLH and immunotherapy treatment-related HLH, are discussed.

Hemophagocytic Syndrome and COVID-19: A Comprehensive Review

Hemophagocytic lymphohistiocytosis (HLH), a hyperinflammatory hyperferritinemic syndrome, is triggered by various etiologies and diseases and can lead to multiorgan dysfunction and death. There are two types of HLH: primary and secondary. Primary HLH (pHLH) is caused by a genetic mutation resulting in dysfunction in cytotoxic T lymphocytes (CTLs), natural killer (NK) cells, hyperactivated immune cells, and hypercytokinemia. In secondary HLH (sHLH), an underlying etiology is the cause of the disease. Infections, malignancy, and autoimmune diseases are well-known triggers for sHLH. Infectious triggers for sHLH are most frequently viruses, where different mechanisms, including dysregulated CTLs and NK cell activity and persistent immune system stimulation, have been reported. Similarly, in severe coronavirus disease 2019 (COVID-19) patients, a hyperinflammatory mechanism leading to hypercytokinemia and hyperferritinemia has been demonstrated. A similar dysfunction in CTLs and NK cells, persistent immune system stimulation with increased cytokines production, and severe end-organ damage have been reported. Therefore, a significant overlap is present between the clinical and laboratory features seen in COVID-19 and sHLH. However, SARS-CoV-2, similar to other viruses, can trigger sHLH. Hence, a diagnostic approach is needed in severe COVID-19 patients presenting with multiorgan failure, in whom sHLH should be considered.

Granulomatous inflammation and hypogammaglobulinemia: Clinical conundrum of familial hemophagocytic lymphohistiocytosis type 5

Familial hemophagocytic lymphohistiocytosis (HLH) is an inherited disorder characterized by systemic hyperinflammation caused by an uncontrolled immune response mediated by T-lymphocytes, natural killer (NK) cells, and macrophages. Most children with familial HLH present within first 2 years of life and can have fatal disease unless hematopoietic stem cell transplant (HSCT) is performed (1). However, few patients may have late presentation and prolonged survival. With increasing awareness and facilities to identify HLH these disorders are being identified beyond infancy (2-4). Clinical and laboratory features are often similar to other primary immune deficiency diseases and pose diagnostic challenges (4-6). We report two patients who presented beyond the first decade of life with HLH, granulomatous inflammation, hypogammaglobulinemia, reduced B cells and were diagnosed to have familial HLH type 5 due to defect in STXBP2 gene.

Haemophagocytic lymphohistiocytosis during pregnancy: a case presentation and literature review

Objectives

Haemophagocytic lymphohistiocytosis (HLH) is a potentially fatal disorder of the immune system that typically occurs in the paediatric population. Diagnosing this rare disease in the adult population is challenging, particularly during pregnancy.

Case presentation

We present a case of a gravid patient developing HLH at week 13 of gestation undergoing a medical termination of pregnancy at 27 weeks due to anhydramnios and associated stopped foetal growth.

Conclusions

Disease triggers could vary from a simple viral infection to the pregnancy as such causing the disorder. Treatment should benefit the mother and limit the foetal harm.

Hemophagocytic Lymphohistiocytosis Secondary to Peripheral T Cell Lymphoma with Rapid Onset and Fatal Progression in a Young Patient: A Case Report and Review of the Literature

BACKGROUND Constant stimulation of lymphocytes and histiocytes can result in hemophagocytic lymphohistiocytosis (HLH), which can be primary or secondary (sHLH). The main causes of sHLH are infections and hematological malignancies, especially non-Hodgkin lymphoma. Despite new insights into the pathogenesis of HLH, the diagnosis and treatment of this immune disorder remain a great challenge. CASE REPORT We present a case of a young adult without comorbidities whose clinical course was nonspecific for several months and resulted in late diagnosis of HLH secondary to peripheral T cell lymphoma (PTCL). The etiological factor of recurring fever, hepatosplenomegaly, and deteriorating condition was unidentified for a long time before fatal sHLH was finally diagnosed. The patient was treated according to the HLH-2004 protocol; however, he did not achieve any response. Unfortunately, due to nonspecific symptoms, lack of lymphadenopathy for a long time, and negative positron emission tomography results, the diagnosis of PTCL was established only after the patient's death. CONCLUSIONS It should be emphasized that early diagnosis is crucial for better prognosis of patients with sHLH. Bone marrow biopsy is worth considering in patients with prolonged fever of unknown origin, hyperferritinemia, splenomegaly, and unexplained cytopenia of 2 or more lineages. Despite the existence of diagnostic and therapeutic protocols available in the literature, the prompt diagnosis and treatment of HLH remains a great challenge. More precise and specific diagnostic tools for HLH are needed.

Identification of germline variants in adults with hemophagocytic lymphohistiocytosis

Some germline variants are predicted to disrupt protein function in HLH-associated genes. Such variants are neither enriched in adult-onset HLH nor associated with specific clinical or laboratory features of HLH.

Adult onset type 2 familial hemophagocytic lymphohistiocytosis with PRF1 c.65delC/c.163C>T compound heterozygous mutations: A case report

BACKGROUND

Familial hemophagocytic lymphohistiocytosis (FHL) is a primary immunodefici-ency disease caused by gene defects. The onset of FHL in adolescents and adults may lead clinicians to ignore or even misdiagnose the disease. To the best of our knowledge, this is the first report to detail the clinical features of type 2 FHL (FHL2) with compound heterozygous perforin (PRF1) defects involving the c.163C>T mutation, in addition to correlation analysis and a literature review.

CASE SUMMARY

We report a case of a 27-year-old male patient with FHL2, who was admitted with a persistent fever and pancytopenia. Through next-generation sequencing technology of hemophagocytic lymphohistiocytosis (HLH)-related genes, we found compound heterozygous mutations of PRF1: c.65delC (p.Pro22Argfs*29) (frameshift mutation, paternal) and c.163C>T (p.Arg55Cys) (missense mutation, maternal). Although he did not receive hematopoietic stem cell transplantation, the patient achieved complete remission after receiving HLH-2004 treatment protocol. To date, the patient has stopped taking drugs for 15 mo, is in a stable condition, and is under follow-up observation.

CONCLUSION

The delayed onset of FHL2 may be related to the PRF1 mutation type, pathogenic variation pattern, triggering factors, and the temperature sensitivity of some PRF1 mutations. For individual, the detailed reason for the delay in the onset of FHL warrants further investigation.

Unraveling subcutaneous panniculitis-like T-cell lymphoma: An association between subcutaneous panniculitis-like T-cell lymphoma, autoimmune lymphoproliferative syndrome, and familial hemophagocytic lymphohistiocytosis

Germline HAVCR2 mutations, recently identified in a large subset of patients with subcutaneous panniculitis-like T-cell lymphoma (SPTCL), are associated with an increased risk of hemophagocytic lymphohistiocytosis (HLH). Discovery of this heritable HLH/SPTCL diathesis has expanded our understanding of a rare and molecularly heterogeneous lymphoma. Furthermore, patients with SPTCL have excellent survival unless they develop HLH. Therefore, through compiling data on SPTCL-related conditions that predispose patients to HLH, we are better able to predict which patients with SPTCL have the greatest risk of mortality. We present the first case of SPTCL with concomitant HLH and autoimmune lymphoproliferative syndrome (ALPS) in a patient who was subsequently diagnosed with familial HLH (F-HLH) attributable to a germline STXBP2 splice-site mutation. She had wild-type HAVCR2. Reports including ours show how SPTCL can evolve in the setting of an exaggerated host inflammatory response attributable to a variety of unusual underlying etiologies.

Functional and genetic testing in adults with HLH reveals an inflammatory profile rather than a cytotoxicity defect

Hemophagocytic lymphohistiocytosis (HLH) is a life-threatening hyperinflammatory condition. Primary HLH occurs early in life as a result of monogenic biallelic mutations affecting lymphocyte cytotoxicity. Secondary HLH occurs mostly in adults secondary to infection, lymphoma, or rheumatic disease. In this latter setting, lymphocyte cytotoxicity status is not known. We conducted a systematic evaluation of natural killer (NK) cell cytotoxicity in adult patients with secondary HLH. Adult patients with secondary HLH were prospectively studied ex vivo for total lymphocyte count and subtype, NK cell phenotype, perforin expression and degranulation, and natural or antibody-dependent cell cytotoxicity, in comparison with patients affected by the same underlying disease without HLH (disease controls [DCs]) and with healthy controls (HCs). Screening for variants of cytotoxity genes was systematically performed. 68 patients were included in the HLH group and 34 each in the DC and HC groups. In HLH patients, severe and transient lymphopenia, activated NK cell phenotype (eg, increased CD69, ICAM-1, HLADR, and CCR5 expression), and decreased capacity of interferon γ production were observed; mean perforin expression was normal; and degranulation tests and NK cell cytotoxicity were not different from those in DCs. A monoallelic variant of uncertain significance affecting a lymphocyte cytotoxicity gene or the perforin variant A91V was observed in almost 50% of the patients. We detected no major intrinsic cytotoxicity dysfunction in secondary HLH patients compared with DCs and no predicted pathogenic gene variant. The activated NK phenotype profile associated with decreased interferon γ production seems similar to those of other hyperinflammatory diseases such as sepsis or systemic juvenile idiopathic arthritis.

Pediatric hemophagocytic lymphohistiocytosis

Hemophagocytic lymphohistiocytosis (HLH) is a syndrome describing patients with severe systemic hyperinflammation. Characteristic features include unremitting fever, cytopenias, hepatosplenomegaly, and elevation of typical HLH biomarkers. Patients can develop hepatitis, coagulopathy, liver failure, central nervous system involvement, multiorgan failure, and other manifestations. The syndrome has a high mortality rate. More and more, it is recognized that while HLH can be appropriately used as a broad summary diagnosis, many pediatric patients actually suffer from an expanding spectrum of genetic diseases that can be complicated by the syndrome of HLH. Classic genetic diseases in which HLH is a typical and common manifestation include pathogenic changes in familial HLH genes (PRF1, UNC13D, STXBP2, and STX11), several granule/pigment abnormality genes (RAB27A, LYST, and AP3B1), X-linked lymphoproliferative disease genes (SH2D1A and XIAP), and others such as NLRC4, CDC42, and the Epstein-Barr virus susceptibility diseases. There are many other genetic diseases in which HLH is an infrequent complication of the disorder as opposed to a prominent manifestation of the disease caused directly by the genetic defect, including other primary immune deficiencies and inborn errors of metabolism. HLH can also occur in patients with underlying rheumatologic or autoinflammatory disorders and is usually designated macrophage activation syndrome in those settings. Additionally, HLH can develop in patients during infections or malignancies without a known (or as-yet-identified) genetic predisposition. This article will attempt to summarize current concepts in the pediatric HLH field as well as offer a practical diagnostic and treatment overview.

[Clinical study of haploidentical hematopoietic stem cell transplantation on 15 cases of adult-onset primary hemophagocytic lymphohistiocytosis]

Objective: This study was designed to evaluate the efficacy of haploidentical hematopoietic stem cell transplantation (haplo-HSCT) for adult-onset primary hemophagocytic lymphohistiocytosis (HLH) . Method: A retrospective study was carried out to analyze the clinical data of 15 adult patients with primary HLH who received haplo-HSCT from January 2013 to October 2019 in Beijing Friendship Hospital, Capital Medical University, Beijing, China. Results: Among the 15 patients included in the study, ten were males and five were females, with a median age of 21 years old (18-52) . Eight of the patients had familial hemophagocytic lymphohistiocytosis type 2 (FHL-2) , four had FHL-3, one had Griscelli syndrome type 2 (GS-2) , one had X-linked lymphoproliferative disease type 1 (XLP-1) , and the other had XLP-2. The median time from HLH diagnosis to transplantation was 7 months (2-46 months) . Seven patients were treated with Bu/Cy condition regimen prior to transplantation. Meanwhile, the other eight cases were treated with TBI/Cy. The median concentration of mononuclear cell (MNC) infusion was 12.6 (9.2-20.3) ×10(8)/kg and CD34(+) cells was 4.91 (2.51-8.37) ×10(6)/kg. The median time of leukocyte engraftment was on day 13 following transplantation (10-23 days) , and the platelet engraftment was on day 12 (9-36) . Graft failure (GF) finally occurred in two patients (one primary GF and one secondary GF) . The cumulative incidence of acute graft-versus-host-disease (GVHD) grades 2 to 4 was 71.4% (10/14) and chronic GVHD was 30.8% (4/13) , respectively. The five-year overall survival (OS) for all 15 cases of primary HLH was 65.5% (95% CI, 34.9%-73.3%) and the transplant-related mortality (TRM) was 26.7% (4/15) . The five-year OS was 87.5% (95% CI, 38.7%-66.3%) in eight patients who received haplo-HSCT subsequent to initial therapy and 42.9% (95% CI, 8.5%-65.2%) in patients seven patients who needed salvage therapy prior to haplo-HSCT (χ(2)=2.387, P=0.122) . The five-year OS was 85.7% (95% CI, 50.4%-89.8%) in eight patients who achieved complete response before haplo-HSCT and 42.9% (95% CI, 6.4%-53.0%) in seven patients with partial response (χ(2)=3.185, P=0.074) . Conclusion: The results indicated that haplo-HSCT is a promising method for the treatment of primary HLH in adults.

Retrospective single-centre analysis of diagnostic approach to adult-onset haemophagocytic lymphohistiocytosis

BACKGROUND

Haemophagocytic lymphohistiocytosis (HLH) is a rare disorder with a poor prognosis characterised by substantial immune activation leading to end-organ failure. In childhood, genetic defects that impair cytotoxic function of natural killer cells and T cells. (HLH) are often identified. In adults, clinical manifestations are similar to those observed in children but the aetiology is often unclear.

AIMS

To evaluate whether poor prognosis for adult HLH is in part due to lack of awareness of the disorder, which results in incomplete investigation and failure to implement timely treatment.

METHODS

We performed a retrospective case series of adult-onset HLH in a tertiary hospital in Australia. We evaluated clinical characteristics, treatment and outcome, and related these to application of standard diagnostic criteria for HLH.

RESULTS

In our centre, incomplete assessment of HLH criteria was common. Serum ferritin was the criterion most commonly assessed. Hyperferritinaemia ≥10 000 μg/L was highly sensitive in detecting patients with adult-onset HLH; however, the majority of patients who had hyperferritinaemia ≥10 000 μg/L did not have adult-onset HLH.

CONCLUSION

The present study highlights the importance of comprehensive application of diagnostic criteria to improve accuracy and timelines of the diagnosis of adult onset HLH.

Genotype characteristics and immunological indicator evaluation of 311 hemophagocytic lymphohistiocytosis cases in China

Background

Primary hemophagocytic lymphohistiocytosis (pHLH) is a genetic disorder that is classically diagnosed by genetic testing. Secondary HLH (sHLH) is usually caused by infections, malignancies, or autoimmune disorders, but may display some mutations or polymorphisms. Rapid immunological assays examining natural killer (NK) cell activity, degranulation function (CD107a), and protein expression related to genetic deficiencies have been recommended for early pHLH identification.

Methods

A retrospective analysis of 311 HLH patients from a Chinese population was performed to evaluate the potential correlations between genetic testing and rapid immunological assays; genotyping characteristics, age of onset, and etiology were examined.

Results

Among the 128 (128/311) patients who were positive in the genetic screening, the most frequently detected mutant gene was UNC13D (29%), followed by LYST (21%), PRF1 (17%), and STXBP2 (10%). Among pHLH patients (n = 39), the majority (67%) had PRF1 and UNC13D defects. FHL-2 was predominant (12/27, 44%) in patients aged under 18, while FHL-3 was the most common (6/12, 50%) in adults. Differences in genetic variant types and etiological components were noted in HLH patients based on the age of onset. NK cell activity and CD107a were observed to show a consistent trend (P_trend < 0.001) when grouping patients according to the severity of the genetic variant type. Moreover, NK cell activity was generally consistent within a certain range of ΔCD107a values (P_trend < 0.001). The PPV for bi-allelic degranulation gene mutations in patients with CD107a < 5% was 38.9% (7/18), while the PPV in patients with CD107a ≤10% was 16.7% (13/78). The PPV for pHLH was 41.4% (29/70) with NK cell activity ≤13%. To further evaluate the diagnostic efficacy of NK cell activity assay in pHLH, a receiver operating characteristic (ROC) curve was generated and showed an area under the curve (AUC) of 0.872, and the optimal cutoff value was determined to be 13.425% with a sensitivity of 84.21% and specificity of 80.67% when the corresponding Youden index was maximized. Flow cytometry screening for deficient proteins, including perforin, SAP, and XIAP, showed a relatively high sensitivity (83.33–93.33%). The positive predictive values (PPVs) of perforin and XIAP were relatively low (20.83–26.92%), but the negative predictive values (NPVs) for all three were excellent (all > 98%).

Conclusions

Various immunological indicators have different clinical prediction and application values for the diagnosis of pHLH. The degree of reduction of immunological indicators also needs attention, and choosing appropriate cutoff value may be of important significance in guiding clinical judgment for pHLH.

Hemophagocytic lymphohistiocytosis in adults: collaborative analysis of 137 cases of a nationwide German registry

Purpose

Hemophagocytic lymphohistiocytosis (HLH) is a severe hyperinflammatory syndrome emerging from a deregulated immune response due to various triggers. In adults, systematic data are sparse, which is why recommendations on diagnosis and management have been adopted from pediatric guidelines. A nationwide clinical registry with associated consulting service as collaborative initiative of HLH-specialized pediatricians and hematologists was initiated to better characterize HLH in adults.

Methods

Patients with proven or suspected HLH were registered by 44 institutions. Both HLH-2004 diagnostic criteria and the HScore (www.saintantoine.aphp.fr/score/) were used to confirm HLH diagnosis. Data referring to underlying disease, treatment, outcome, clinical presentation and laboratory findings were recorded.

Results

The study included 137 patients and provides the first systematic data on adult HLH in Germany. Median age was 50 years with a wide range (17–87 years), 87 patients (63.5%) were male. Most common triggering diseases were infections in 61 patients (44.5%) and malignancies in 48 patients (35%). Virtually all patients had elevated ferritin concentrations, and 74% had peak concentrations greater than 10,000 µg/l. At time of analysis, 67 of 131 patients (51%) had died. Patients with malignancy-associated HLH had the shortest median survival (160 days), however no statistically significant difference between subgroups was observed (p = 0.077). Platelets under 20*10⁹/l and low albumin concentrations (< 20 g/l) were associated with poor overall and 30-day survival.

Conclusion

Close multidisciplinary case consultation and cooperation is mandatory when treating adult HLH patients. Early contact with reference centers is recommended, especially in relapsing or refractory disease.

Supplementary Information

The online version contains supplementary material available at 10.1007/s00432-020-03139-4.

Natural Killer Cells in Systemic Autoinflammatory Diseases: A Focus on Systemic Juvenile Idiopathic Arthritis and Macrophage Activation Syndrome

Natural killer (NK) cells are innate immune lymphocytes with potent cytolytic and immune-regulatory activities. NK cells are well-known for their ability to kill infected and malignant cells in a fast and non-specific way without prior sensitization. For this purpose, NK cells are equipped with a set of cytotoxic molecules such as perforin and apoptosis-inducing proteins. NK cells also have the capacity to produce large amounts of cytokines and chemokines that synergize with their cytotoxic function and that ensure interaction with other immune cells. A less known feature of NK cells is their capacity to kill non-infected autologous cells, such as immature dendritic cells and activated T cells and monocytes. Via the release of large amounts of TNF-α and IFN-γ, NK cells may contribute to disease pathology. Conversely they may exert a regulatory role through secretion of immuno-regulatory cytokines such as GM-CSF, IL-13, and IL-10. Thus, NK cells may be important target and effector cells in the pathogenesis of autoinflammatory diseases, in particular in those disorders associated with a cytokine storm or in conditions where immune cells are highly activated. Key examples of such diseases are systemic juvenile idiopathic arthritis (sJIA) and its well-associated complication, macrophage activation syndrome (MAS). sJIA is a chronic childhood immune disorder of unknown etiology, characterized by arthritis and systemic inflammation, including a daily spiking fever and evanescent rash. MAS is a potentially fatal complication of autoimmune and autoinflammatory diseases, and most prevalently associated with sJIA. MAS is considered as a subtype of hemophagocytic lymphohistiocytosis (HLH), a systemic hyperinflammatory disorder characterized by defective cytotoxic pathways of cytotoxic T and NK cells. In this review, we describe the established features of NK cells and provide the results of a literature survey on the reported NK cell abnormalities in monogenic and multifactorial autoinflammatory disorders. Finally, we discuss the role of NK cells in the pathogenesis of sJIA and MAS.

Familial hemophagocytic lymphohistiocytosis in a girl with a novel homozygous mutation of STX11: A case report

RATIONALE

Familial hemophagocytic lymphohistiocytosis (FHL) is a rare fatal autosomal recessively inherited disease and can be divided into five types. The mortality of untreated patients is up to 95% and it can be healed only after immunochemotherapy for disease control and hematopoietic stem cell transplantation. Clinical data of a girl with late-onset and recurrent hemophagocytic lymphohistiocytosis (HLH) was retrospectively analyzed to determine the etiology and potential pathogenic gene.

PATIENT CONCERNS AND CLINICAL FINDINGS

The proband was a female child patient from a consanguineous marriage family who was 11 years old, and clinically manifested delayed (onset at the age of 4 years and 6 months) and recrudescent HLH. Both of her elder brothers died at the ages of 4 and 5 years, respectively. The patient had a degranulation function defect of CD107a in natural killer (NK) cells, and the degranulation function of cytotoxic T lymphocytes (CTL) obviously declined (ΔMFI: 1.4%, normal ≧2.8%); the degranulation function of NK cells and CTL of her father was also obviously reduced. To identify possible underlying genetic causes, gene mutation analysis was undertaken. A novel homozygous nonsense mutation in STX11 (c.49C>T, p.Q17X) was documented, arising from both her parents.

DIAGNOSIS

According to the clinical manifestations and detection results of STX11, the diagnosis of FHL-type 4 was confirmed and her parents were heterozygotic carriers.

INTERVENTIONS AND OUTCOMES

Good responses to HLH-2004 chemotherapy had been achieved for each onset, and the maximum remission duration (without taking any drug) was 23 months. The patient has been alive for 82 months since the onset, and has stopped taking dexamethasone and etoposide, but is still on oral cyclosporine to maintain the treatment. She has performed HLA matching and now is actively looking for a donor to prepare hematopoietic stem cell transplantation.

CONCLUSIONS

Relevant gene detections should be implemented at the earliest for young patients from consanguineous marriages and with a family history of HLH so as to provide a basis for etiological diagnosis and radical treatment by hematopoietic stem cell transplantation and provide accurate genetic counseling for family members.

To Transplant or Not to Transplant? Late-Onset Primary HLH in a Patient: A Case Report and Review of Literature

Primary, or familial, hemophagocytic lymphohistiocytosis (P-HLH) is a rare inherited autosomal-recessive immune deficiency which generally manifests during infancy or early childhood. Recent literature suggests an increased number of reports of late-onset P-HLH, especially in association with infection and underlying malignancy. The authors describe a case of subcutaneous T-cell lymphoma in a 8-year-old child that was complicated by primary, perforin-deficient HLH. In contrast, we examined retrospective data for 19 cases of late-onset P-HLH with available treatment data and compared the results of conservative medical therapy with hematopoietic stem cell transplant (HSCT) postremission therapy. Our patient displayed compound heterozygous mutations in PRF1 that have not been described in the literature previously: allele 1 [c.786_801del(p.Gln263fs)] and allele 2 [c.886T>C(p.Tyr296His)]. Of the 19 cases analyzed, 14 achieved remission. Postremission, 7 of 14 (50%) received HSCT and were reported alive at a median time of 24 months, 5 of 14 (36%) received medical therapy and were reported alive at a median time of 24 months, and 2 of 14 (14%) received medical therapy and died at a median of 73 months postremission. Our retrospective literature review suggests that some patients can survive late-onset, perforin-deficient, P-HLH without the potential lifelong risks of HSCT when in the first remission.

Aberrant X chromosome skewing and acquired clonal hematopoiesis in adult-onset common variable immunodeficiency

Advances in genomic medicine have elucidated an increasing number of genetic etiologies for patients with common variable immunodeficiency (CVID). However, there is heterogeneity in clinical and immunophenotypic presentations and a limited understanding of the underlying pathophysiology of many cases. The primary defects in CVID may extend beyond the adaptive immune system, and the combined defect in both the myeloid and lymphoid compartments suggests the mechanism may involve bone marrow output and earlier progenitors. Using the methylation profile of the human androgen receptor (AR) gene as a surrogate epigenetic marker for bone marrow clonality, we examined the hematopoietic compartments of patients with CVID. Our data show that clonal hematopoiesis is common among patients with adult-onset CVID who do not have associated noninfectious complications. Nonblood tissues did not show a skewed AR methylation status, supporting a model of an acquired clonal hematopoietic event. Attenuation of memory B cell differentiation into long-lived plasma cells (CD20^–CD27⁺CD38⁺CD138⁺) was associated with marked changes in the postdifferentiation methylation profile, demonstrating the functional consequence of clonal hematopoiesis on humoral immunity in these patients. This study sheds light on a potential etiology of a subset of patients with CVID, and the findings suggest that it is a stage of an acquired lymphocyte maturation disorder.

Clonal hematopoiesis is common among a subset of patients with common variable immunodeficiency (CVID), suggesting that CVID may be a stage of lymphoid dysplasia.

GATA2 mutation underlies hemophagocytic lymphohistiocytosis in an adult with primary cytomegalovirus infection

We report a case of a 27-year old woman with persistent fever and pancytopenia who had multiple episodes of a hemophagocytic lymphohistiocytosis (HLH) like condition. The criterion for HLH was satisfied; primary cytomegalovirus (CMV) infection was identified as the cause. Further examination revealed a GATA binding protein 2 mutation. Reports of GATAs deficiency presenting with HLH after primary CMV infection is very limited. As early recognition and diagnosis will improve patients' outcomes, internists and infectious disease specialists should be aware of this disease.

Recommendations for the management of hemophagocytic lymphohistiocytosis in adults

Hemophagocytic lymphohistiocytosis (HLH) is a severe hyperinflammatory syndrome induced by aberrantly activated macrophages and cytotoxic T cells. The primary (genetic) form, caused by mutations affecting lymphocyte cytotoxicity and immune regulation, is most common in children, whereas the secondary (acquired) form is most frequent in adults. Secondary HLH is commonly triggered by infections or malignancies but may also be induced by autoinflammatory/autoimmune disorders, in which case it is called macrophage activation syndrome (MAS; or MAS-HLH). Most information on the diagnosis and treatment of HLH comes from the pediatric literature. Although helpful in some adult cases, this raises several challenges. For example, the HLH-2004 diagnostic criteria developed for children are commonly applied but are not validated for adults. Another challenge in HLH diagnosis is that patients may present with a phenotype indistinguishable from sepsis or multiple organ dysfunction syndrome. Treatment algorithms targeting hyperinflammation are frequently based on pediatric protocols, such as HLH-94 and HLH-2004, which may result in overtreatment and unnecessary toxicity in adults. Therefore, dose reductions, individualized tailoring of treatment duration, and an age-dependent modified diagnostic approach are to be considered. Here, we present expert opinions derived from an interdisciplinary working group on adult HLH, sponsored by the Histiocyte Society, to facilitate knowledge transfer between physicians caring for pediatric and adult patients with HLH, with the aim to improve the outcome for adult patients affected by HLH.

Pathogenic Gene Mutations or Variants Identified by Targeted Gene Sequencing in Adults With Hemophagocytic Lymphohistiocytosis

Hemophagocytic lymphohistiocytosis (HLH) can be classified into primary HLH and secondary HLH. Primary HLH usually occurs in infants and children with an underlying genetic defect, and there are also teens and occasional adults with primary HLH. Most cases with secondary HLH are adult patients with secondary triggers including infections, malignancies, and autoimmune diseases. The distinction between primary HLH and secondary HLH seems to be less straightforward, as patients with secondary HLH may also have genetic defects while primary HLH can be triggered by secondary causes. In this study, using amplicon-based targeted gene sequencing (TGS), we sequenced eighteen HLH-related genes in 112 adult HLH cases, which were mostly secondary HLH. Mutations or rare variants were identified in 48 cases (42.9%). All the variants except one were missense variants, and biallelic gene mutations were identified in 3 cases in which only one case harbored homogenous missense mutation. Recurrent variants including UNC13D p.G863D and AP3B1 p.T359A are much more prevalent in our cohort than in normal East Asian population, and in silico analysis predicted pathogenicity of these variants. In conclusion, according to our study, genetic defects may also contribute to the development of adult HLH cases or secondary HLH cases.

Systemic Epstein-Barr Virus-Positive T/NK Lymphoproliferative Diseases With SH2D1A/XIAP Hypomorphic Gene Variants

X-linked lymphoproliferative disease (XLP) is one of the X-linked primary immunodeficiency diseases (PIDs) with defective immune response to Epstein-Barr virus (EBV) infection. Chronic active EBV infection (CAEBV) and EBV-hemophagocytic lymphohistiocytosis (HLH) are recognized as systemic EBV-positive T-cell and natural killer (NK)-cell lymphoproliferative diseases (LPDs) arising from the clonal proliferations of EBV-infected T cells and NK cells. A high incidence of CAEBV in East Asia implies the unknown genetic predisposition. In patients with XLP, EBV-infected cells are generally B cells. No mutation of SH2D1A/XIAP genes has ever been identified in patients with systemic EBV-positive T-cell and NK-cell LPD. We report herewith a male case of NK-cell type CAEBV with SH2D1A hypomorphic mutation (c.7G > T, p.Ala3Ser), two male cases of CAEBV/EBV-HLH with XIAP hypomorphic variant (c.1045_1047delGAG, p.Glu349del), and another female case of CD4⁺CAEBV with the same XIAP variant. The female underwent bone marrow transplantation from an HLA-matched sister with the XIAP variant and obtained a complete donor chimerism and a cure of laryngeal LPD lesion, but then suffered from donor-derived CD4⁺ T cell EBV-LPD. These observations demonstrated that SH2D1A and XIAP genes are critical for the complete regulation of EBV-positive T/NK cell LPD. X-linked lymphoproliferative disease (XLP) is one of the X-linked primary immunodeficiency diseases (PIDs) reported to have a defective immune response to Epstein-Barr virus (EBV) infection. Mutations in SH2D1A and XIAP genes cause XLP. Systemic EBV-positive T-cell and natural killer (NK)-cell lymphoproliferative diseases (LPDs) consist of three major types: EBV-positive hemophagocytic lymphohistiocytosis (HLH), chronic active EBV infection (CAEBV), and EBV-positive T-cell/NK-cell lymphoma. CAEBV is recognized as a poor prognostic disease of EBV-associated T-cell and NK-cell LPD arising from the clonal proliferation of EBV-infected T cells (CD4⁺, CD8⁺, and TCRγδ⁺) and/or NK cells. The majority of cases with CAEBV were reported from East Asia and South America. In Caucasian patients with CAEBV disease, the target of infection is exclusively B cells. These imply a genetic predisposition to EBV-positive T/NK cell LPD according to ethnicity. In reported cases with XLP, EBV-infected cells are B cells. On the other hand, no mutation of SH2D1A/XIAP genes have been determined in patients with T/NK-cell-type (Asian type) CAEBV. We here describe, for the first time, four case series of CAEBV/EBV-HLH patients who carried the hypomorphic variants of XLP-related genes. These cases included a male patient with CAEBV carrying SH2D1A hypomorphic mutation (c.7G > T, p.Ala3Ser) and two male patients with CAEBV/EBV-HLH carrying the XIAP hypomorphic variant (c.1045_1047delGAG, p.Glu349del), along with another female patient with CAEBV carrying the same XIAP variant. The female case underwent bone marrow transplantation from a healthy HLA-matched sister having the same XIAP variant. Although a complete donor chimerism was achieved with the resolution of laryngeal LPD lesions, systemic donor-derived CD4⁺ T-cell EBV-LPD developed during the control phase of intractable graft- vs. -host-disease. These observations demonstrated that SH2D1A and XIAP genes are critical for the complete regulation of systemic EBV-positive T/NK-cell LPD.

A multicenter study of patients with multisystem Langerhans cell histiocytosis who develop secondary hemophagocytic lymphohistiocytosis

BACKGROUND

Langerhans cell histiocytosis (LCH) is a rare myeloid neoplasm characterized by the presence of abnormal CD1a-positive (CD1a⁺ )/CD207⁺ histiocytes. Hemophagocytic lymphohistiocytosis (HLH) represents a spectrum of hyperinflammatory syndromes typified by the dysregulated activation of the innate and adaptive immune systems. Patients with LCH, particularly those with multisystem (MS) involvement, can develop severe hyperinflammation mimicking that observed in HLH. Nevertheless, to the authors' knowledge, little is known regarding the prevalence, timing, risk factors for development, and outcomes of children and young adults who develop HLH within the context of MS-LCH (hereafter referred to LCH-associated HLH).

METHODS

To gain further insights, the authors conducted a retrospective, multicenter study and collected data regarding all patients diagnosed with MS-LCH between 2000 and 2015.

RESULTS

Of 384 patients with MS-LCH, 32 were reported by their primary providers to have met the diagnostic criteria for HLH, yielding an estimated 2-year cumulative incidence of 9.3% ± 1.6%. The majority of patients developed HLH at or after the diagnosis of MS-LCH, and nearly one-third (31%) had evidence of an intercurrent infection. Patient age <2 years at the time of diagnosis of LCH; female sex; LCH involvement of the liver, spleen, and hematopoietic system; and a lack of bone involvement each were found to be independently associated with an increased risk of LCH-associated HLH. Patients with MS-LCH who met the criteria for HLH had significantly poorer 5-year survival compared with patients with MS-LCH who did not meet the criteria for HLH (69% vs 97%; P < .0001).

CONCLUSIONS

Given its inferior prognosis, further efforts are warranted to enhance the recognition and optimize the treatment of patients with LCH-associated HLH.

Type 2 familial hemophagocytic lymphohistiocytosis in half brothers: A case report

RATIONALE

We describe a novel case of half-brothers suffering from type 2 familial hemophagocytic lymphohistiocytosis (FHL).

PATIENT CONCERNS

A 15-year-old Chinese child was admitted to the hematology department. PRF1 gene coding revealed that he was c.282C>A/p.N94K heterozygous and had a c.1349C>T/p.T450M heterozygous mutation. One year later, his younger halfbrother suffered from the same disease. PRF1 gene coding revealed that the younger brother was c.282C>A/p.T450M heterozygous with a c.1349C>T/p.T450M heterozygous mutation. His mother and grandfather were confirmed to have c.1349C>T/p.T450M heterozygous mutations in exon 3.

DIAGNOSES

Half-brothers were diagnosed for type 2 familial hemophagocytic lymphohistiocytosis INTERVENTIONS:: To our knowledge, this is a possible FHL and the children's mother may be a pathogenic gene carrier.

OUTCOMES

After being treated with the HLH-04 schedule, the symptoms of half-brothers were all improved.

LESSONS SUBSECTIONS

Therefore, once FHL is diagnosed, HSCT needs to be done early, even if no perfect match is found.

Epstein-Barr virus-associated hemophagocytic lymphohistiocytosis in adults and adolescents-a life-threatening disease: analysis of 133 cases from a single center

OBJECTIVES

Epstein-Barr virus-associated hemophagocytic lymphohistiocytosis is the most common type of infection-associated HLH. Previous studies were focused on pediatric EBV-HLH patients, therefore there lack of adult data.

METHOD

We performed a retrospective analysis of 133 EBV-HLH patients (≥14 years old) in Beijing Friendship Hospital from March 2009 to April 2016 to evaluate the clinical manifestation and the effects and prognosis of existing regimens of EBV-HLH in adult and adolescents.

RESULTS

Of these patients, 91 male and 42 female cases had a median age of 26 (14-77) years. EBV-DNA load on admission was at a median of 6.6E + 05 IU/ml. The one-year mortality of these patients was 78%. 112 patients received the HLH-94/04 regimen as the initial treatment, 52 patients (46.43%) had response. Of the 6 patients who received the L-DEP regimen as the initial treatment, 5 patients (83.33%) had response. The rest 15 patients received initial treatment without etoposide, 5 cases achieved PR. 69 refractory or relapsed patients received DEP or L-DEP regimen, 55 (79.71%) cases had response. In addition, who received the L-DEP regimen, with the overall response rate significantly higher than the DEP regimen (88.37% VS 65.38%, P = 0.031). 36 out of 133 EBV-HLH patients eventually received allo-HSCT, with the overall survival rate of 52.78%. In summary, EBV-HLH is a highly lethal disease.

CONCLUSION

DEP/L-DEP was a good salvage treatment. L-DEP might be a more effective first-line initial regimen than HLH-94/04 regimen for EBV-HLH. Finally, allo-HSCT is an effective radical treatment for EBV-HLH.

Comparing hemophagocytic lymphohistiocytosis in pediatric and adult patients

PURPOSE OF REVIEW

Hemophagocytic lymphohistiocytosis (HLH) has long been thought of primarily as a pediatric disease. However, this syndrome may occur secondary to underlying malignancies, infections, and autoimmune diseases, in adult patients. Here, we seek to highlight similarities and differences between pediatric and adult HLH, knowledge gaps, and areas of active research.

RECENT FINDINGS

Malignancy is a more frequent driver of HLH in adults, present in nearly half. Prognosis is poor as compared with nonmalignant HLH. Prognosis in adults is generally worse than pediatric patients, suggesting that age and other comorbid illnesses not surprisingly affect the outcome of HLH. Diagnostic and treatment approaches are more variable in adults, likely contributing to poorer outcomes. The frequency of mutations in HLH-causing genes is higher than had been anticipated in adults, although with a higher frequency of uniallelic and hypomorphic mutations than in children.

SUMMARY

Optimizing diagnostic criteria for earlier detection may benefit both children and adults. Standardizing treatment approaches in adults will be more difficult because of the variability in triggering illnesses, but a more standardized or algorithmic approach will likely be beneficial. More research into the role of uniallelic and hypomorphic mutations in adults is necessary, to understand treatment and prognostic implications.

Late-onset hemophagocytic lymphohistiocytosis with neurological presentation

Missense mutations in genes involved in familial hemophagocytic lymphohistiocytosis can delay the onset of this life-threatening disease. In children and adults, early recognition of aspecific features as neurological symptoms is crucial as urgent treatment is required.

A Personalized Diagnostic and Treatment Approach for Macrophage Activation Syndrome and Secondary Hemophagocytic Lymphohistiocytosis in Adults

OBJECTIVE

We assessed the clinical features and outcomes based on therapeutic options adopted during hospital stay for adult patients with macrophage activation syndrome and secondary hemophagocytic lymphohistiocytosis (MAS/sHLH).

METHODS

We conducted a retrospective chart review of all adult patients (age ≥ 18 years) diagnosed with MAS/sHLH at our center between 2010 and 2015. Inclusion criteria for patients were diagnosis of MAS/sHLH during admission and patients meeting at least 5 out of 8 of Henter's criteria or at least 4 out of 6 of the criteria that were tested.

RESULTS

Nineteen adult patients with MAS/sHLH met the inclusion criteria from January 2010 to October 2015 (median age 48 years; female 68.4%). Treatment had been personalized, depending on the clinical presentation and course of disease. Majority of the patients received anakinra, cyclosporine, intravenous immunoglobulins (IVIG), and steroids. Fourteen (74%) patients survived, with clinical improvement by the time of discharge. After excluding the three patients with underlying leukemia/lymphoma who opted for palliative care and subsequently died, the survival rate was 88%.

CONCLUSION

A modified diagnostic and treatment protocol for adult patients with MAS/sHLH that incorporated graded introduction of medications based on clinical presentation and cytokine profile resulted in the best adult survival rate reported in literature.

Finding a Balance between Protection and Pathology: The Dual Role of Perforin in Human Disease

Perforin is critical for controlling viral infection and tumor surveillance. Clinically, mutations in perforin are viewed as unfavorable, as lack of this pore-forming protein results in lethal, childhood disease, familial hemophagocytic lymphohistiocytosis type 2 (FHL 2). However, many mutations in the coding region of PRF1 are not yet associated with disease. Animal models of viral-associated blood–brain barrier (BBB) disruption and experimental cerebral malaria (ECM) have identified perforin as critical for inducing pathologic central nervous system CNS vascular permeability. This review focuses on the role of perforin in both protecting and promoting human disease. It concludes with a novel hypothesis that diversity observed in the PRF1 gene may be an example of selective advantage that protects an individual from perforin-mediated pathology, such as BBB disruption.

A consensus review on malignancy-associated hemophagocytic lymphohistiocytosis in adults

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

[Hemophagocytic lymphohistiocytosis : A diagnostic challenge on the ICU]

BACKGROUND

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

OBJECTIVES

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

MATERIALS AND METHODS

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

RESULTS

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

CONCLUSIONS

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

Weathering the storm: Improving therapeutic interventions for cytokine storm syndromes by targeting disease pathogenesis

Cytokine storm syndromes require rapid diagnosis and treatment to limit the morbidity and mortality caused by the hyperinflammatory state that characterizes these devastating conditions. Herein, we discuss the current knowledge that guides our therapeutic decision-making and personalization of treatment for patients with cytokine storm syndromes. Firstly, ICU-level supportive care is often required to stabilize patients with fulminant disease while additional diagnostic evaluations proceed to determine the underlying cause of cytokine storm. Pharmacologic interventions should be focused on removing the inciting trigger of inflammation and initiation of an individualized immunosuppressive regimen when immune activation is central to the underlying disease pathophysiology. Monitoring for a clinical response is required to ensure that changes in the therapeutic regimen can be made as clinically warranted. Escalation of immunosuppression may be required if patients respond poorly to the initial therapeutic interventions, while a slow wean of immunosuppression in patients who improve can limit medication-related toxicities. In certain scenarios, a decision must be made whether an individual patient requires hematopoietic cell transplantation to prevent recurrence of disease. Despite these interventions, significant morbidity and mortality remains for cytokine storm patients. Therefore, we use this review to propose a clinical schema to guide current and future attempts to design rational therapeutic interventions for patients suffering from these devastating conditions, which we believe speeds the diagnosis of disease, limits medication-related toxicities, and improves clinical outcomes by targeting the heterogeneous and dynamic mechanisms driving disease in each individual patient.

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

目的

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

方法

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

结果

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

结论

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

Rapidly Fatal Hemophagocytic Lymphohistiocytosis Developing Within Six Days Following Deceased-Donor Renal Transplantation: Case Report

Hemophagocytic lymphohistiocytosis (HLH) is an often fatal hyperinflammatory syndrome that may complicate malignancy, infection, rheumatic disease, or immunosuppression. HLH after kidney transplantation is most often triggered by infection, usually Herpes viruses such as cytomegalovirus and Epstein-Barr virus (EBV). It usually occurs early after transplantation. We present a case of HLH triggered by reactivation of EBV that pursued a rapidly fatal course within 6 days of receiving a deceased-donor kidney transplant. This case serves to remind transplant clinicians to consider HLH when cytopenias and hyperinflammation are atypical for the usual post-transplantation course. We discuss pitfalls in diagnosis and suggestions for treatment in this setting.

Hemophagocytic lymphohistiocytosis in a patient with Sjögren's syndrome: case report and review

Hemophagocytic lymphohistiocytosis (HLH) is a very rare syndrome with a mortality up to 95% of cases if not treated. It is characterised by an excessive activation of the immune system that leads to a disproportionate and destructive inflammatory response. The high mortality rates are in part due to a delay in the diagnosis, and therefore clinicians must maintain a high index of suspicion. When the treatment is started early, the survival rate reaches around 55% of cases. HLH usually presents with persistent fever, pancytopenia, and organomegaly and is associated with very high levels of serum ferritin. In this manuscript, we present the case of a patient with primary Sjögren's syndrome who developed HLH after an acute infection by Cytomegalovirus. We will describe and discuss the pathogenesis, differential diagnosis and a pragmatic approach to the treatment for this critically important and, when diagnosed early, potentially curable syndrome.

Advances in the pathogenesis of primary and secondary haemophagocytic lymphohistiocytosis: differences and similarities

Haemophagocytic lymphohistiocytosis (HLH) comprises a heterogeneous spectrum of hyperinflammatory conditions that are inherited (primary HLH) or acquired in a context of infections, malignancies or autoimmune/autoinflammatory disorders (secondary HLH). Genetic defects in the cytotoxic machinery of natural killer and CD8(+) T cells underlie primary HLH, with residual cytotoxicity determining disease severity. Improved sequencing techniques have expanded the range of causal mutations and have redefined many cases of secondary HLH as primary HLH and vice versa, blurring the distinction between both subtypes. These insights allow HLH to be conceptualized as a threshold disease, in which interplay between various genetic and environmental factors causes progressive inflammation into a critical point, beyond which uncontrolled activation of immune cells and excessive cytokine production give rise to the cardinal symptoms of HLH. Various pathogenic pathways may thus converge to a common end stage of fulminant HLH.

A Heterozygous RAB27A Mutation Associated with Delayed Cytolytic Granule Polarization and Hemophagocytic Lymphohistiocytosis

Frequently fatal, primary hemophagocytic lymphohistiocytosis (HLH) occurs in infancy resulting from homozygous mutations in NK and CD8 T cell cytolytic pathway genes. Secondary HLH presents after infancy and may be associated with heterozygous mutations in HLH genes. We report two unrelated teenagers with HLH and an identical heterozygous RAB27A mutation (c.259G→C). We explore the contribution of this Rab27A missense (p.A87P) mutation on NK cell cytolytic function by cloning it into a lentiviral expression vector prior to introduction into the human NK-92 cell line. NK cell degranulation (CD107a expression), target cell conjugation, and K562 target cell lysis was compared between mutant- and wild-type-transduced NK-92 cells. Polarization of granzyme B to the immunologic synapse and interaction of mutant Rab27A (p.A87P) with Munc13-4 were explored by confocal microscopy and proximity ligation assay, respectively. Overexpression of the RAB27A mutation had no effect on cell conjugate formation between the NK and target cells but decreased NK cell cytolytic activity and degranulation. Moreover, the mutant Rab27A protein decreased binding to Munc13-4 and delayed granzyme B polarization toward the immunologic synapse. This heterozygous RAB27A mutation blurs the genetic distinction between primary and secondary HLH by contributing to HLH via a partial dominant-negative effect.

Targeted high-throughput sequencing for genetic diagnostics of hemophagocytic lymphohistiocytosis

Background

Hemophagocytic lymphohistiocytosis (HLH) is a rapid-onset, potentially fatal hyperinflammatory syndrome. A prompt molecular diagnosis is crucial for appropriate clinical management. Here, we validated and prospectively evaluated a targeted high-throughput sequencing approach for HLH diagnostics.

Methods

A high-throughput sequencing strategy of 12 genes linked to HLH was validated in 13 patients with previously identified HLH-associated mutations and prospectively evaluated in 58 HLH patients. Moreover, 2504 healthy individuals from the 1000 Genomes project were analyzed in silico for variants in the same genes.

Results

Analyses revealed a mutation detection sensitivity of 97.3 %, an average coverage per gene of 98.0 %, and adequate coverage over 98.6 % of sites previously reported as mutated in these genes. In the prospective cohort, we achieved a diagnosis in 22 out of 58 patients (38 %). Genetically undiagnosed HLH patients had a later age at onset and manifested higher frequencies of known secondary HLH triggers. Rare, putatively pathogenic monoallelic variants were identified in nine patients. However, such monoallelic variants were not enriched compared with healthy individuals.

Conclusions

We have established a comprehensive high-throughput platform for genetic screening of patients with HLH. Almost all cases with reduced natural killer cell function received a diagnosis, but the majority of the prospective cases remain genetically unexplained, highlighting genetic heterogeneity and environmental impact within HLH. Moreover, in silico analyses of the genetic variation affecting HLH-related genes in the general population suggest caution with respect to interpreting causality between monoallelic mutations and HLH. A complete understanding of the genetic susceptibility to HLH thus requires further in-depth investigations, including genome sequencing and detailed immunological characterization.

Electronic supplementary material

The online version of this article (doi:10.1186/s13073-015-0244-1) contains supplementary material, which is available to authorized users.

Dynamic Changes, Cut-Off Points, Sensitivity, and Specificity of Laboratory Data to Differentiate Macrophage Activation Syndrome from Active Disease

PURPOSE

To compare the laboratory data and changes in these data between patients with MAS and patients with flare-up of the autoimmune diseases.

METHODS

In a prospective study, the static laboratory data and dynamic changes in the selected data in 17 consecutive patients with MAS and 53 patients with active disease of SJIA, PJIA, Kawasaki disease, and SLE were compared. The ROC curve analysis was used to evaluate cut-off points, sensitivity, and specificity of the static and dynamic laboratory data to differentiate between MAS and active disease.

RESULTS

In the MAS group, the mean CRP3, ALT, AST, total bilirubin, ferritin, LDH, PT, PTT, and INR were significantly higher and the mean WBC2, PMN2, Lymph2, Hgb1, 2, 3, ESR2, serum albumin, and sodium were significantly lower than in control group. Some of the important cut-off points were PLT2 < 209000/microliter, AST > 38.5, ALT > 38, WBC < 8200 × 103/UL, ferritin > 5277 ng/mL.

CONCLUSION

The dynamic changes in some laboratory data, especially PLT, can differentiate between MAS and active disease. The changes in WBC, PMN, and ESR and the levels of the liver enzymes may also be helpful in the early differentiation. Very high levels of ferritin may also help the diagnosis along with other clinical and laboratory signs.