• Adeno-associated virus 6 (AAV6)
• CRISPR-Cas9 systems
• Gene editing efficiency
• Gene therapy
• Genome editing
• Humans
• Immunodeficiencies
• Memory T cells
• Perforin
• Ribonucleoproteins

• QGP
• familial hemophagocytic lymphohistiocytosis (FHLH)
• genetics
• hemophagocytic lymphohistiocytosis (HLH)
• novel variants

• Animals
• Mice
• Humans
• Lymphohistiocytosis, Hemophagocytic/genetics
• Lymphohistiocytosis, Hemophagocytic/therapy
• CRISPR-Cas Systems
• Epstein-Barr Virus Infections/genetics
• Epstein-Barr Virus Infections/therapy
• Memory T Cells
• Herpesvirus 4, Human
• Membrane Proteins/genetics

• Adolescents
• Familial HLH
• Hemophagocytic lymphohistiocytosis (HLH)
• Primary immunodeficiency
• Secondary HLH
• Young adults

• Humans
• Adolescent
• Young Adult
• Lymphohistiocytosis, Hemophagocytic/diagnosis
• Lymphohistiocytosis, Hemophagocytic/genetics
• Lymphohistiocytosis, Hemophagocytic/therapy
• Genetic Predisposition to Disease
• Neoplasms/complications
• Mutation

• Humans
• Lymphohistiocytosis, Hemophagocytic/complications
• Lymphohistiocytosis, Hemophagocytic/diagnosis
• Facial Paralysis/etiology
• Perforin

• Allogeneic hematopoietic stem cell transplantation
• Hemophagocytic lymphohistiocytosis
• Heterozygous mutation
• PRF1

• Male
• Humans
• Adult
• Lymphohistiocytosis, Hemophagocytic/genetics
• Lymphohistiocytosis, Hemophagocytic/therapy
• Perforin/genetics
• Mutation
• Mutation, Missense
• Hematopoietic Stem Cell Transplantation

• Epstein-Barr virus infections
• Lymphohistiocytosis, hemophagocytic
• Mutation
• Perforin

• Adult
• Female
• Male
• Humans
• Child, Preschool
• Child
• Adolescent
• Young Adult
• Epstein-Barr Virus Infections/complications
• Epstein-Barr Virus Infections/genetics
• Herpesvirus 4, Human
• Lymphohistiocytosis, Hemophagocytic/genetics
• Perforin/genetics
• Retrospective Studies

• FHL – familial hemophagocytic lymphohistiocytosis
• HLH - hemophagocytic lymphohistiocytosis
• NGS - next generation sequencing
• degranulation
• flow cytometric assay
• perforin

• Humans
• Lymphohistiocytosis, Hemophagocytic/etiology
• Lymphohistiocytosis, Hemophagocytic/genetics
• Genetic Predisposition to Disease

• hemophagocytic lymphohistiocytosis
• liver transplantation
• pediatric acute liver failure
• perforin deficiency
• primary immune deficiency

• central nervous system disease
• genome sequencing
• lymphoma
• perforin
• primary hemophagocytic lymphohistiocytosis

• National Natural Science Foundation of China

• Mendelian genetic diseases
• autoinflammatory disorders
• familial hemophagocytic lymphohistiocytosis (FHL)
• interferonopathies
• interleukin-1
• neuroinflammation
• primary immunodeficiencies
• type I interferon

• Alleles
• Animals
• Autoimmunity
• Biomarkers
• Cytokines/metabolism
• Genetic Association Studies
• Genetic Diseases, Inborn/complications
• Genetic Diseases, Inborn/diagnosis
• Genetic Diseases, Inborn/genetics
• Genetic Predisposition to Disease
• Humans
• Immune Tolerance
• Immunity/genetics
• Inflammation Mediators/metabolism
• Magnetic Resonance Imaging
• Mutation
• Neuroinflammatory Diseases/diagnosis
• Neuroinflammatory Diseases/etiology
• Phenotype

• East Asian
• Korean
• carrier frequency
• familial hemophagocytic lymphohistiocytosis
• gnomAD

• case report
• cytokines
• familial hemophagocytic lymphohistiocytosis
• hemophagocytic lymphohistiocytosis
• neonatal thrombocytopenia

• Fever/etiology
• Flow Cytometry
• Genetic Testing
• Humans
• Infant, Newborn
• Lymphohistiocytosis, Hemophagocytic/diagnosis
• Lymphohistiocytosis, Hemophagocytic/drug therapy
• Lymphohistiocytosis, Hemophagocytic/genetics
• Male
• Membrane Proteins/genetics
• Mutation/genetics
• Remission Induction

• Brain Diseases
• Child
• Child, Preschool
• Humans
• Infant
• Lymphohistiocytosis, Hemophagocytic/diagnostic imaging
• Lymphohistiocytosis, Hemophagocytic/genetics
• Magnetic Resonance Imaging
• Neuroimaging
• Retrospective Studies

• G0902001 Medical Research Council

• Genetic mutation
• Hemophagocytic lympho-histiocytosis
• PRF1
• STX11
• STXBP2
• UNC13D

Recently, primary immune regulatory disorders have been described as a subset of inborn errors of immunity that are dominated by immune mediated pathology. As the pathophysiology of disease is elucidated, use of biologic modifiers have been increasingly used successfully to treat disease mediated clinical manifestations. Hematopoietic cell transplant (HCT) has also provided definitive therapy in several PIRDs. Although biologic modifiers have been largely successful at treating disease related manifestations, data are lacking regarding long term efficacy, safety, and their use as a bridge to HCT. This review highlights biologic modifiers in the treatment of several PIRDs and there use as a therapeutic bridge to HCT.

• Abatacept
• CTLA4
• Emapalumab
• Jakinib
• PIRD
• Pi3Kinase
• STAT1
• STAT3

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.

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.

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.

• Familial hemophagocytic lymphohistiocytosis
• Perforin
• PRF1 mutation
• Late-onset
• Case report

Hemophagocytic lymphohistiocytosis (HLH) is a syndrome of immune dysregulation characterized by hyperactivation of the immune system, excessive cytokine secretion and severe systemic inflammation. HLH is classified as familial (FHL) when associated with mutations in PRF1, UNC13D, STX11, and STXBP2 genes. There is limited information available about the clinical and mutational spectrum of FHL patients in Indian population. This study is a retrospective analysis of 101 molecularly characterized FHL patients over the last 10 years from 20 different referral centers in India. FHL2 and FHL3 together accounted for 84% of cases of FHL in our cohort. Patients belonging to different FHL subtypes were indistinguishable based on clinical and biochemical parameters. However, flow cytometry-based assays viz. perforin expression and degranulation assay were found to be specific and sensitive in diagnosis and classification of FHL patients. Molecular characterization of respective genes revealed 76 different disease-causing mutations including 39 (51%) novel mutations in PRF1, UNC13D, STX11, and STXBP2 genes. Overall, survival was poor (28%) irrespective of the age of onset or the type of mutation in our cohort. Altogether, this article sheds light on the current scenario of FHL in India. Our data reveal a wide genetic heterogeneity of FHL in the Indian population and confirms the poor prognosis of FHL. This study also emphasizes that though mutational analysis is important for diagnostic confirmation of FHL, flow cytometry based assays help significantly in rapid diagnosis and functional validation of novel variants identified.

• HLH-targeted therapy
• NGS
• degranulation
• familial hemophagocytic lymphohistocytosis
• flow cytomertry
• perforin

Hemophagocytic lymphohistiocytosis (HLH) is a rare but severe, life-threatening inflammatory condition if untreated. We aimed to investigate the etiologies, outcomes, and risk factors for death in children and adults with HLH.

The medical records of patients who met the HLH criteria of two regional university hospitals in Korea between January 2001 and December 2019 were retrospectively investigated.

Sixty patients with HLH (35 children and 25 adults) were included. The median age at diagnosis was 7.0 years (range, 0.1–83 years), and the median follow-up duration was 8.5 months (range, 0–204 months). Four patients had primary HLH, 48 patients had secondary HLH (20 infection-associated, 18 neoplasm-associated, and 10 autoimmune-associated HLH), and eight patients had HLH of unknown cause. Infection was the most common cause in children (14/35, 40.0%), whereas neoplasia was the most common cause in adults (13/25, 52.0%). Twenty-eight patients were treated with HLH-2004/94 immunochemotherapy. The 5-year overall survival (OS) rate for all HLH patients was 59.9%. The 5-year OS rates for patients with primary, infection-associated, neoplasm-associated, autoimmune-associated, and unknown cause HLH were 25.0%, 85.0%, 26.7%, 87.5%, and 62.5%, respectively. Using multivariate analysis, neoplasm-induced HLH (p=0.001) and a platelet count <50×10⁹/L (p=0.008) were identified as independent risk factors for poor prognosis in patients with HLH.

Infection was the most common cause of HLH in children, while it was neoplasia in adults. The 5-year OS rate for all HLH patients was 59.9%. HLH caused by an underlying neoplasm or a low platelet count at the time of diagnosis were risk factors for poor prognosis.

• Hemophagocytic lymphohistiocytosis
• Human herpesvirus 4
• Lymphoproliferative disorders
• Neoplasms
• Survival

• Chronic active epstein-barr virus
• Familial hemophagocytic lymphohistiocytosis
• Fever of Unknown Origin
• Lymphadenopathy
• Perforin

• Adult
• Chronic Disease
• Diagnosis, Differential
• Epstein-Barr Virus Infections/complications
• Epstein-Barr Virus Infections/diagnosis
• Epstein-Barr Virus Infections/virology
• Herpesvirus 4, Human/isolation & purification
• Humans
• India/ethnology
• Lymphohistiocytosis, Hemophagocytic/complications
• Lymphohistiocytosis, Hemophagocytic/diagnosis
• Lymphohistiocytosis, Hemophagocytic/genetics
• Male
• Perforin/analysis

• CNS disease
• CNS inflammation
• Familial hemophagocytic lymphohistiocytosis
• therapy

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.

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.

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%).

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.

• Genetic testing
• Primary hemophagocytic lymphohistiocytosis
• Rapid immunological indicators

Familial hemophagocytic lymphohistiocytosis Type 2 (FHL2) associated central nervous system (CNS) involvement is less understood in children, especially when considering neurologic manifestations as part of the initial presentation. We conducted a retrospective review of the clinical manifestations and genetic abnormality of four Han Chinese children with FHL2 who were patients at the neurology department of Beijing Children’s Hospital from November 2015 to October 2018. These four patients initially manifested CNS symptoms in their disease presentation, and all four patients were misdiagnosed as having ademyelinating disease, such as acute disseminated encephalomyelitis and multiple sclerosis. Given these misdiagnoses, it is important that general physicians and pediatricians maintain awareness of the possibility of FHL2 as a differential diagnosis. These four cases included neurologic manifestations including seizures, ataxia, spasticity, gait disorder, and coma. Bilateral abnormal signals in the cerebrum, including in white matter, gray matter, and junctions were discovered. Enhanced magnetic resonance imaging (MRI) in these patients showed spot or ring enhancement and/or hemorrhage. These patients all possessed a compound heterozygote mutation PRF1 gene. Whole exome sequencing analysis revealed seven different mutations (three novel mutations) spread over the PRF1 gene and a heterozygous missense mutation c.1349C > T [p.T450M] that was present in two patients. Three novel mutations, c.634T > C[p.Y212H], c.1083_1094del[p.361_364del], and c.1306G > T [p.D436Y], were discovered and through in silico analysis were discovered to be deleterious. Neurologic manifestations were the initial symptoms of FHL2 in these patients in addition to the expected leukopenia and hepatosplenomegaly. Whole exome sequencing of PRF1 for patients with similar presentations would facilitate prompt and accurate diagnosis and treatment.

• familial hemophagocytic lymphohistiocytosis Type-2
• mutation
• neurological manifestations
• pediatric patients
• perforin 1

Background: Therapy for acute lymphoblastic leukemia (ALL) are currently initially efficient, but even if a high percentage of patients have an initial complete remission (CR), most of them relapse. Recent data shows that immunotherapy with either bispecific T-cell engagers (BiTEs) of chimeric antigen receptor (CAR) T cells can eliminate residual chemotherapy-resistant B-ALL cells.

Objective: The objective of the manuscript is to present improvements in the clinical outcome for chemotherapy-resistant ALL in the real-life setting, by describing Romania's experience with bispecific antibodies for B-cell ALL.

Methods: We present the role of novel therapies for relapsed B-cell ALL, including the drugs under investigation in phase I-III clinical trials, as a potential bridge to transplant. Blinatumomab is presented in a critical review, presenting both the advantages of this drug, as well as its limitations.

Results: Bispecific antibodies are discussed, describing the clinical trials that resulted in its approval by the FDA and EMA. The real-life setting for relapsed B-cell ALL is described and we present the patients treated with blinatumomab in Romania.

Conclusion: In the current manuscript, we present blinatumomab as a therapeutic alternative in the bridge-to-transplant setting for refractory or relapsed ALL, to gain a better understanding of the available therapies and evidence-based data for these patients in 2019.

• acute lymphoblastic leukemia
• bispecific antobodies
• blinatumoman
• bridge-to-transplant
• real life setting

Hemophagocytic lymphohistiocytosis (HLH) is a rare group of disorders of immune dysregulation characterized by clinical symptoms of severe inflammation. There are basically two types of clinical scenarios: Familial HLH and sporadic HLH. It is thought that the syndrome is implicated in the development of infections, malignancies, and autoimmune diseases. HLH, whether primary or secondary, is characterized by activated macrophages in hematopoietic organs, hepatosplenomegaly, cytopenia, and fever; however, HLH complicated with polyserositis (PS) has never been reported.

We present a case of fever in a 46-year-old previously healthy Chinese woman complicated by pericardial, pleural, and abdomen effusions. She had no contact with sick individuals, recent travel, illicit drug use, or new sexual contacts. She did not consume alcohol or tobacco and lacked a family history of other diseases. Antibiotics were prescribed for suspected infection, and acute liver injury subsequently occurred. Contrast-enhanced computed tomography showed mild pericardial effusion, pleural effusion, hepatosplenomegaly, and a large amount of ascites. A full blood count revealed leukopenia and thrombocytopenia. Increased ferritin and triglyceride levels were observed. The test for Epstein-Barr (EB) virus DNA was positive. This suggests that EB virus replication and EB virus infection existed. Additional studies showed hemophagocytosis in bone marrow biopsy specimens. The patient’s condition progressed rapidly. After providing symptomatic support treatment, eliminating immune stimuli, and administering comprehensive cyclosporine and dexamethasone treatment, the patient’s condition continued to progress, and the patient’s family members decided to stop treatment; the patient subsequently died.

This case shows the significance of considering HLH as part of the evaluation of unexplained fever and PS of unknown origin.

• Hemophagocytic lymphohistiocytosis
• Polyserositis
• Liver injury
• Fever
• Case report

• combined immunodeficiency
• gain of function (GOF)
• immunedysregulation
• monoclonals
• precision medicine
• primary immunodeficiency diseases (PID)
• small molecules

Advances in flow cytometry have led to greatly improved primary immunodeficiency (PID) diagnostics. This is due to the fact that patient blood cells in suspension do not require further processing for analysis by flow cytometry, and many PIDs lead to alterations in leukocyte numbers, phenotype, and function. A large portion of current PID assays can be classified as “phenotyping” assays, where absolute numbers, frequencies, and markers are investigated using specific antibodies. Inherent drawbacks of antibody technology are the main limitation to this type of testing. On the other hand, “functional” assays measure cellular responses to certain stimuli. While these latter assays are powerful tools that can be used to detect defects in entire pathways and distinguish variants of significance, it requires samples with robust viability and also skilled processing. In this review, we concentrate on hemophagocytic lymphohistiocytosis (HLH), describing the principles and accuracies of flow cytometric assays that have been proven to assist in the screening diagnosis of primary HLH.

• HLH
• XLP
• clinical diagnostics
• clinical laboratory tests
• diagnostic accuracy
• flow cytometry
• hemophagocytic lymphohistiocytosis
• primary immunodeficiencies

• Child
• Disease Management
• Hodgkin Disease/complications
• Hodgkin Disease/diagnosis
• Humans
• Lymphocytes/pathology
• Lymphohistiocytosis, Hemophagocytic/diagnosis
• Lymphohistiocytosis, Hemophagocytic/etiology

• 17973 Cancer Research UK

Primary immunodeficiency diseases (PID) are a clinically and immunologically heterogeneous group of disorders of immune system. Diagnosis of these disorders is often challenging and requires identification of underlying genetic defects, complemented by a comprehensive evaluation of immune system. Flow cytometry, with its advances in the last few decades, has emerged as an indispensable tool for enumeration as well as characterization of immune cells. Flow cytometric evaluation of the immune system not only provides clues to underlying genetic defects in certain PIDs and helps in functional validation of novel genetic defects, but is also useful in monitoring immune responses following specific therapies. India has witnessed significant progress in the field of flow cytometry as well as PID over last one decade. Currently, there are seven Federation of Primary Immunodeficiency Diseases (FPID) recognized centers across India, including two Indian Council of Medical research (ICMR) funded centers of excellence for diagnosis, and management of PIDs. These centers offer comprehensive care for PIDs including flow cytometry based evaluation. The key question which always remains is how one selects from the wide array of flow cytometry based tests available, and whether all these tests should be performed before or after the identification of genetic defects. This becomes crucial, especially when resources are limited and patients have to pay for the investigations. In this review, we will share some of our experiences based on evaluation of a large cohort of hemophagocytic lymphohistiocytosis, severe combined immunodeficiency, and chronic granulomatous disease, and the lessons learned for optimum use of this powerful technology for diagnosis of these disorders.

• chronic granulomatous disease (CGD)
• familial HLH
• flow cytometry
• primary immunodeficiency disorders
• severe combined immunodeficiency (SCID)

• Inherited platelet function disorders
• RASGRP2 gene
• Splicing mutation

• Blood Platelets
• Guanine Nucleotide Exchange Factors
• Humans
• Pedigree
• Platelet Glycoprotein GPIIb-IIIa Complex
• Thrombasthenia

• gene variants
• hemophagocytic lymphohistiocytosis
• racial differences
• variant spectrum

• hematopoietic stem cell transplantation
• isolated central nervous system hemophagocytic lymphohistiocytosis
• primary hemophagocytic lymphohistiocytosis

• Hemophagocytic lymphohistiocytosis
• late‐onset
• neurology
• perforin

• cytotoxic lymphocytes
• founder mutation
• gene mutation
• lymphoma

• Exome sequencing
• Hemophagocytic lymphohistiocytosis
• Molecular diagnosis
• Mutation screening
• Next-generation sequencing

• malignancy
• primary immunodeficiency

• Wellcome Trust
• G1000758 Medical Research Council
• G1001367 Medical Research Council