Publications by authors named "Craig Platt"

45 Publications

Multisystem Inflammation and Susceptibility to Viral infections in Human ZNFX1 Deficiency.

J Allergy Clin Immunol 2021 Apr 16. Epub 2021 Apr 16.

Division of Immunology and Children's Research Center, University Children's Hospital Zurich, Zurich, Switzerland.

Background: The recognition of viral nucleic acids is one of the primary triggers for a type I interferon-mediated antiviral immune response. Inborn errors of type I interferon immunity can be associated with increased inflammation and/or increased susceptibility to viral infections, as a result of dysbalanced interferon production. NFX1-type zinc-finger-containing 1 (ZNFX1) is an interferon-stimulated double-strand RNA sensor that restricts the replication of RNA viruses in mice. ZNFX1's role in the human immune response is not known.

Objective: We studied 15 patients from 8 families with an autosomal recessive immunodeficiency characterized by severe infections by both RNA and DNA viruses and virally triggered inflammatory episodes with hemophagocytic-lymphohistiocytosis-like disease, early-onset seizures, as well as renal and lung disease.

Methods: Whole exome sequencing was performed on 13 patients from 8 families. We investigated the transcriptome, post-transcriptional regulation of interferon-stimulated genes (ISGs) and predisposition to viral infections in primary cells from patients and controls stimulated with synthetic double-stranded nucleic acids.

Results: Deleterious homozygous and compound heterozygous ZNFX1 variants were identified in all 13 patients. Stimulation of patient-derived primary cells with synthetic double-stranded nucleic acids was associated with a deregulated pattern of expression of ISGs and alterations in the half-life of ISGs mRNA and was associated with poorer clearance of virus infections by monocytes.

Conclusion: ZNFX1 is an important regulator of the response to double-stranded nucleic acids stimuli following viral infections. ZNFX1 deficiency predisposes to severe viral infections and a multisystem inflammatory disease.
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http://dx.doi.org/10.1016/j.jaci.2021.03.045DOI Listing
April 2021

Pulmonary manifestations of immune dysregulation in CTLA-4 haploinsufficiency and LRBA deficiency.

Pediatr Pulmonol 2021 Mar 12. Epub 2021 Mar 12.

Division of Pulmonary Medicine, Boston Children's Hospital, Harvard Medical School, Boston, Massachusetts, USA.

Objective: The primary immunodeficiency syndromes of cytotoxic T lymphocyte-associated protein 4 (CTLA-4) haploinsufficiency and lipopolysaccharide-responsive and beige-like anchor protein (LRBA) deficiency present with multisystem immune dysregulation. The aim of this study was to characterize and compare the pulmonary manifestations of these two diseases.

Methods: We retrospectively analyzed the pulmonary clinical, radiologic, and histopathologic characteristics of six patients with CTLA-4 haploinsufficiency and four patients with LRBA deficiency with pulmonary involvement followed at a large tertiary care center.

Results: Chronic respiratory symptoms were more frequent in patients with LRBA deficiency versus CTLA-4 haploinsufficiency (3/4 vs. 1/6). Cough was the most common respiratory symptom. Abnormalities in pulmonary exam and pulmonary function testing were more frequent in LRBA deficiency (4/4, 2/4) compared to CTLA-4 haploinsufficiency (1/6, 2/6). Chest computed tomography (CT) findings included mediastinal lymphadenopathy (4/4 in LRBA deficiency vs. 1/4 in CTLA-4 haploinsufficiency), pulmonary nodules (4/4, 3/4), ground-glass opacification (4/4, 3/4), and bronchiectasis (3/4, 1/4). Lymphocytic inflammation, concentrated bronchovasculocentrically and paraseptally, was the predominant pathologic finding and was observed in all patients who had lung biopsies (N = 3 with LRBA deficiency; N = 3 with CTLA-4 haploinsufficiency).

Conclusion: Despite phenotypic overlap amongst these diseases, LRBA deficiency demonstrated greater severity of pulmonary disease, indicated by respiratory symptoms, pulmonary exam, and intrathoracic radiologic findings. Chest CT was the most sensitive indicator of pulmonary involvement in both disorders. Lymphocytic inflammation is the key histologic feature of both disorders. Pediatric pulmonologists should consider these disorders of immune dysregulation in the relevant clinical context to provide earlier diagnosis, comprehensive pulmonary evaluation and treatment.
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http://dx.doi.org/10.1002/ppul.25373DOI Listing
March 2021

Ten Years of Newborn Screening for Severe Combined Immunodeficiency (SCID) in Massachusetts.

J Allergy Clin Immunol Pract 2021 May 16;9(5):2060-2067.e2. Epub 2021 Feb 16.

New England Newborn Screening Program, Commonwealth Medicine, University of Massachusetts Medical School, Worcester, Mass; Department of Pediatrics, University of Massachusetts Medical School, Worcester, Mass. Electronic address:

Background: Massachusetts began newborn screening (NBS) for severe combined immunodeficiency (SCID) using measurement of T-cell receptor excision circles (TRECs) from dried blood spots.

Objective: We describe developments and outcomes from the first 10 years of this program (February 1, 2009, to January 31, 2019).

Methods: TREC values, diagnostic, and outcome data from all patients screened for SCID were evaluated.

Results: NBS of 720,038 infants prompted immunologic evaluation of 237 (0.03%). Of 237, 9 were diagnosed with SCID/leaky SCID (4% of referrals vs 0.001% general population). Another 7 were diagnosed with other combined immunodeficiencies, and 3 with athymia. SCID/leaky SCID incidence was approximately 1 in 80,000, whereas approximately 1 in 51,000 had severe T-cell lymphopenia for which definitive treatment was indicated. All patients with SCID/leaky SCID underwent hematopoietic cell transplant or gene therapy with 100% survival. One patient with athymia underwent successful thymus transplant. No known cases of SCID were missed. Compared with outcomes from the 10 years before SCID NBS, survival trended higher (9 of 9 vs 4 of 7), likely due to a lower rate of infection before treatment.

Conclusions: Our data support a single NBS testing-and-referral algorithm for all gestational ages. Despite lower median TREC values in premature infants, the majority for all ages are well above the TREC cutoff and the algorithm, which selects urgent (undetectable TREC) and repeatedly abnormal TREC values, minimizes referral. We also found that low naïve T-cell percentage is associated with a higher risk of SCID/CID, demonstrating the utility of memory/naïve T-cell phenotyping as part of follow-up flow cytometry.
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http://dx.doi.org/10.1016/j.jaip.2021.02.006DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC8113135PMC
May 2021

Combined immunodeficiency due to a mutation in the γ1 subunit of the coat protein I complex.

J Clin Invest 2021 Feb;131(3)

Division of Immunology, Boston Children's Hospital, Harvard Medical School, Boston, Massachusetts, USA.

The coat protein I (COPI) complex mediates retrograde trafficking from the Golgi to the endoplasmic reticulum (ER). Five siblings with persistent bacterial and viral infections and defective humoral and cellular immunity had a homozygous p.K652E mutation in the γ1 subunit of COPI (γ1-COP). The mutation disrupts COPI binding to the KDEL receptor and impairs the retrieval of KDEL-bearing chaperones from the Golgi to the ER. Homozygous Copg1K652E mice had increased ER stress in activated T and B cells, poor antibody responses, and normal numbers of T cells that proliferated normally, but underwent increased apoptosis upon activation. Exposure of the mutants to pet store mice caused weight loss, lymphopenia, and defective T cell proliferation that recapitulated the findings in the patients. The ER stress-relieving agent tauroursodeoxycholic acid corrected the immune defects of the mutants and reversed the phenotype they acquired following exposure to pet store mice. This study establishes the role of γ1-COP in the ER retrieval of KDEL-bearing chaperones and thereby the importance of ER homeostasis in adaptive immunity.
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http://dx.doi.org/10.1172/JCI140494DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7843234PMC
February 2021

Efficacy and economics of targeted panel versus whole-exome sequencing in 878 patients with suspected primary immunodeficiency.

J Allergy Clin Immunol 2021 Feb 2;147(2):723-726. Epub 2020 Sep 2.

Division of Immunology, Boston Children's Hospital, Harvard Medical School, Boston, Mass.

Background: Next-generation sequencing has become a first-line tool for the diagnosis of primary immunodeficiency. However, patient access remains limited because of restricted insurance coverage and a lack of guidelines addressing the use of targeted panels versus whole-exome sequencing (WES).

Objectives: We sought to compare targeted next-generation sequencing with WES in a global population of patients with primary immunodeficiency.

Methods: This was a longitudinal study of 878 patients with likely primary immunodeficiency sequenced between 2010 and 2020. Most patients (n = 780) were first sequenced using a 264 gene panel. This was followed by WES in selected cases if a candidate gene was not found. A subset of patients (n = 98) were selected for a WES-only pipeline if the history was atypical for genes within the targeted panel.

Results: Disease-causing variants were identified in 498 of the 878 probands (56%), encompassing 152 distinct monogenic disorders. Sixteen patients had disorders that were novel at the time of sequencing (1.8%). Diagnostic yield in patients sequenced by targeted panel was 56% (433 of 780 patients), with subsequent WES leading to an additional 18 diagnoses (overall diagnostic yield 58%, 451 of 780 patients). The WES-only approach had a diagnostic yield of 45% (45 of 98 patients), reflecting that these cases had less common clinical and laboratory phenotypes. Cost analysis, based on current commercial WES and targeted panel prices, demonstrated savings ranging from $300 to $950 with a WES-only approach, depending on diagnostic yield.

Conclusions: Advantages of WES over targeted next-generation sequencing include simplified workflow, reduced overall cost, and the potential for identification of novel diseases.
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http://dx.doi.org/10.1016/j.jaci.2020.08.022DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7870529PMC
February 2021

Immune dysregulation and multisystem inflammatory syndrome in children (MIS-C) in individuals with haploinsufficiency of SOCS1.

J Allergy Clin Immunol 2020 11 25;146(5):1194-1200.e1. Epub 2020 Aug 25.

Division of Immunology, Boston Children's Hospital, Harvard Medical School, Boston, Mass. Electronic address:

Background: We studied 2 unrelated patients with immune thrombocytopenia and autoimmune hemolytic anemia in the setting of acute infections. One patient developed multisystem inflammatory syndrome in children in the setting of a severe acute respiratory syndrome coronavirus 2 infection.

Objectives: We sought to identify the mechanisms underlying the development of infection-driven autoimmune cytopenias.

Methods: Whole-exome sequencing was performed on both patients, and the impact of the identified variants was validated by functional assays using the patients' PBMCs.

Results: Each patient was found to have a unique heterozygous truncation variant in suppressor of cytokine signaling 1 (SOCS1). SOCS1 is an essential negative regulator of type I and type II IFN signaling. The patients' PBMCs showed increased levels of signal transducer and activator of transcription 1 phosphorylation and a transcriptional signature characterized by increased expression of type I and type II IFN-stimulated genes and proapoptotic genes. The enhanced IFN signature exhibited by the patients' unstimulated PBMCs parallels the hyperinflammatory state associated with multisystem inflammatory syndrome in children, suggesting the contributions of SOCS1 in regulating the inflammatory response characteristic of multisystem inflammatory syndrome in children.

Conclusions: Heterozygous loss-of-function SOCS1 mutations are associated with enhanced IFN signaling and increased immune cell activation, thereby predisposing to infection-associated autoimmune cytopenias.
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http://dx.doi.org/10.1016/j.jaci.2020.07.033DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7445138PMC
November 2020

Distinct clinical and immunological features of SARS-CoV-2-induced multisystem inflammatory syndrome in children.

J Clin Invest 2020 11;130(11):5942-5950

Division of Immunology and.

BACKGROUNDPediatric SARS-CoV-2 infection can be complicated by a dangerous hyperinflammatory condition termed multisystem inflammatory syndrome in children (MIS-C). The clinical and immunologic spectrum of MIS-C and its relationship to other inflammatory conditions of childhood have not been studied in detail.METHODSWe retrospectively studied confirmed cases of MIS-C at our institution from March to June 2020. The clinical characteristics, laboratory studies, and treatment response were collected. Data were compared with historic cohorts of Kawasaki disease (KD) and macrophage activation syndrome (MAS).RESULTSTwenty-eight patients fulfilled the case definition of MIS-C. Median age at presentation was 9 years (range: 1 month to 17 years); 50% of patients had preexisting conditions. All patients had laboratory confirmation of SARS-CoV-2 infection. Seventeen patients (61%) required intensive care, including 7 patients (25%) who required inotrope support. Seven patients (25%) met criteria for complete or incomplete KD, and coronary abnormalities were found in 6 cases. Lymphopenia, thrombocytopenia, and elevation in inflammatory markers, D-dimer, B-type natriuretic peptide, IL-6, and IL-10 levels were common but not ubiquitous. Cytopenias distinguished MIS-C from KD and the degree of hyperferritinemia and pattern of cytokine production differed between MIS-C and MAS. Immunomodulatory therapy given to patients with MIS-C included intravenous immune globulin (IVIG) (71%), corticosteroids (61%), and anakinra (18%). Clinical and laboratory improvement were observed in all cases, including 6 cases that did not require immunomodulatory therapy. No mortality was recorded in this cohort.CONCLUSIONMIS-C encompasses a broad phenotypic spectrum with clinical and laboratory features distinct from KD and MAS.FUNDINGThis work was supported by the National Institutes of Health, National Institute of Arthritis and Musculoskeletal and Skin Diseases; the National Institute of Allergy and Infectious Diseases; Rheumatology Research Foundation Investigator Awards and Medical Education Award; Boston Children's Hospital Faculty Career Development Awards; the McCance Family Foundation; and the Samara Jan Turkel Center.
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http://dx.doi.org/10.1172/JCI141113DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7598077PMC
November 2020

A family history of SCID and unrevealing WES: An approach to management and guidance of patients.

Clin Immunol 2020 09 4;218:108520. Epub 2020 Jul 4.

Division of Immunology, Boston Children's Hospital, Harvard Medical School, Boston, MA, USA.

Severe Combined Immunodeficiency (SCID) is a genetically heterogeneous group of disorders characterized by severe T cell lymphopenia and defective T and B cell function. Without prompt diagnosis and early intervention, patients with SCID typically die from infection within the first year of life. Advances in molecular genetics have led to rapid and efficient diagnosis of SCID cases, particularly when paired with newborn screening. However, some cases remain unsolved, and this is of particular relevance to families that plan to have more children. Here we report a patient who died from complications of SCID in whom whole exome sequencing failed to reveal a candidate variant. We describe how Sanger sequencing of parents was used to study the genomic regions that were poorly covered by WES, and how immune phenotyping results were used in the setting of genetic counseling.
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http://dx.doi.org/10.1016/j.clim.2020.108520DOI Listing
September 2020

The haemodynamics of the human placenta in utero.

PLoS Biol 2020 05 28;18(5):e3000676. Epub 2020 May 28.

Sir Peter Mansfield Imaging Centre, School of Physics and Astronomy, University of Nottingham, Nottingham, United Kingdom.

We have used magnetic resonance imaging (MRI) to provide important new insights into the function of the human placenta in utero. We have measured slow net flow and high net oxygenation in the placenta in vivo, which are consistent with efficient delivery of oxygen from mother to fetus. Our experimental evidence substantiates previous hypotheses on the effects of spiral artery remodelling in utero and also indicates rapid venous drainage from the placenta, which is important because this outflow has been largely neglected in the past. Furthermore, beyond Braxton Hicks contractions, which involve the entire uterus, we have identified a new physiological phenomenon, the 'utero-placental pump', by which the placenta and underlying uterine wall contract independently of the rest of the uterus, expelling maternal blood from the intervillous space.
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http://dx.doi.org/10.1371/journal.pbio.3000676DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7255609PMC
May 2020

Immunoglobulins in the treatment of COVID-19 infection: Proceed with caution!

Clin Immunol 2020 07 11;216:108459. Epub 2020 May 11.

Division of Immunology, Boston Children's Hospital, Boston, MA, United States of America. Electronic address:

The COVID-19 pandemic is one of the greatest infectious challenges in recent history. Presently, few treatment options exist and the availability of effective vaccines is at least one year away. There is an urgent need to find currently available, effective therapies in the treatment of patients with COVID-19 infection. In this review, we compare and contrast the use of intravenous immunoglobulin and hyperimmune globulin in the treatment of COVID-19 infection.
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http://dx.doi.org/10.1016/j.clim.2020.108459DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7211658PMC
July 2020

A Case of STK4 Deficiency with Complications Evoking Mycobacterial Infection.

J Clin Immunol 2020 05 11;40(4):665-669. Epub 2020 May 11.

Paediatric Allergy and Immunology Unit, Children's Hospital, Ain Shams University, Cairo, Egypt.

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http://dx.doi.org/10.1007/s10875-020-00783-wDOI Listing
May 2020

Genotype and functional correlates of disease phenotype in deficiency of adenosine deaminase 2 (DADA2).

J Allergy Clin Immunol 2020 06 13;145(6):1664-1672.e10. Epub 2020 Jan 13.

Division of Immunology, Boston Children's Hospital, Harvard Medical School, Boston, Mass; Division of Rheumatology, Inflammation and Immunity, Brigham and Women's Hospital, Harvard Medical School, Boston, Mass.

Background: Deficiency of adenosine deaminase 2 (DADA2) is a syndrome with pleiotropic manifestations including vasculitis and hematologic compromise. A systematic definition of the relationship between adenosine deaminase 2 (ADA2) mutations and clinical phenotype remains unavailable.

Objective: We sought to test whether the impact of ADA2 mutations on enzyme function correlates with clinical presentation.

Methods: Patients with DADA2 with severe hematologic manifestations were compared with vasculitis-predominant patients. Enzymatic activity was assessed using expression constructs reflecting all 53 missense, nonsense, insertion, and deletion genotypes from 152 patients across the DADA2 spectrum.

Results: We identified patients with DADA2 presenting with pure red cell aplasia (n = 5) or bone marrow failure (BMF, n = 10) syndrome. Most patients did not exhibit features of vasculitis. Recurrent infection, hepatosplenomegaly, and gingivitis were common in patients with BMF, of whom half died from infection. Unlike patients with DADA2 with vasculitis, patients with pure red cell aplasia and BMF proved largely refractory to TNF inhibitors. ADA2 variants associated with vasculitis predominantly reflected missense mutations with at least 3% residual enzymatic activity. In contrast, pure red cell aplasia and BMF were associated with missense mutations with minimal residual enzyme activity, nonsense variants, and insertions/deletions resulting in complete loss of function.

Conclusions: Functional interrogation of ADA2 mutations reveals an association of subtotal function loss with vasculitis, typically responsive to TNF blockade, whereas more extensive loss is observed in hematologic disease, which may be refractory to treatment. These findings establish a genotype-phenotype spectrum in DADA2.
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http://dx.doi.org/10.1016/j.jaci.2019.12.908DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7282972PMC
June 2020

Dysregulated actin dynamics in activated PI3Kδ syndrome.

Clin Immunol 2020 01 21;210:108311. Epub 2019 Nov 21.

Division of Immunology, Boston Children's Hospital, Harvard Medical School, Boston, MA, USA.

Activated PI3Kδ syndrome (APDS) Type I results from gain-of-function mutations in PIK3CD, which encodes the p110δ subunit of PI3Kδ. Abnormal actin dynamics have been hypothesized to contribute to the lymphopenia associated with this disease but have not been studied in patients with APDS. We report a patient with APDS who had widespread necrotic skin lesions that were responsive specifically to immunosuppressive therapy. EBV-transformed lymphoblastoid cells (EBV-LCLs) from patients with APDS exhibit increased polymerized actin and increased apoptosis, suggesting a contribution of impaired actin dynamics to this disease.
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http://dx.doi.org/10.1016/j.clim.2019.108311DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6989370PMC
January 2020

Heuristic neural network approach in histological sections detection of hydatidiform mole.

J Med Imaging (Bellingham) 2019 Oct 5;6(4):044501. Epub 2019 Nov 5.

Consultant Perinatal Pathologist, University Hospitals Bristol NHS Foundation Trust, Bristol, United Kingdom.

A heuristic-based, multineural network (MNN) image analysis as a solution to the problematical diagnosis of hydatidiform mole (HM) is presented. HM presents as tumors in placental cell structures, many of which exhibit premalignant phenotypes (choriocarcinoma and other conditions). HM is commonly found in women under age 17 or over 35 and can be partial HM or complete HM. Appropriate treatment is determined by correct categorization into PHM or CHM, a difficult task even for expert pathologists. Image analysis combined with pattern recognition techniques has been applied to the problem, based on 15 or 17 image features. The use of limited data for training and validation set was optimized using a -fold validation technique allowing performance measurement of different MNN configurations. The MNN technique performed better than human experts at the categorization for both the 15- and 17-feature data, promising greater diagnostic consistency, and further improvements with the availability of larger datasets.
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http://dx.doi.org/10.1117/1.JMI.6.4.044501DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6830426PMC
October 2019

Diagnostic interpretation of genetic studies in patients with primary immunodeficiency diseases: A working group report of the Primary Immunodeficiency Diseases Committee of the American Academy of Allergy, Asthma & Immunology.

J Allergy Clin Immunol 2020 01 27;145(1):46-69. Epub 2019 Sep 27.

Departments of Pediatrics and Medicine, University of South Florida, St Petersburg, Fla; Division of Pediatric Allergy/Immunology, Johns Hopkins-All Children's Hospital, St Petersburg, Fla; Division of Pediatric Allergy Immunology, Massachusetts General Hospital, Boston, Mass.

Genetic testing has become an integral component of the diagnostic evaluation of patients with suspected primary immunodeficiency diseases. Results of genetic testing can have a profound effect on clinical management decisions. Therefore clinical providers must demonstrate proficiency in interpreting genetic data. Because of the need for increased knowledge regarding this practice, the American Academy of Allergy, Asthma & Immunology Primary Immunodeficiency Diseases Committee established a work group that reviewed and summarized information concerning appropriate methods, tools, and resources for evaluating variants identified by genetic testing. Strengths and limitations of tests frequently ordered by clinicians were examined. Summary statements and tables were then developed to guide the interpretation process. Finally, the need for research and collaboration was emphasized. Greater understanding of these important concepts will improve the diagnosis and management of patients with suspected primary immunodeficiency diseases.
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http://dx.doi.org/10.1016/j.jaci.2019.09.009DOI Listing
January 2020

A novel truncating mutation in MYD88 in a patient with BCG adenitis, neutropenia and delayed umbilical cord separation.

Clin Immunol 2019 10 10;207:40-42. Epub 2019 Jul 10.

Division of Immunology, Boston Children's Hospital, Harvard Medical School, Boston, MA, USA. Electronic address:

Mutations in MYD88 cause susceptibility to invasive bacterial infections through impaired signaling downstream of toll-like receptors (TLRs) and IL-1 receptors. We studied a patient presenting with neutropenia, delayed umbilical cord separation, BCG adenitis, andP. aeruginosapneumonia. Next-generation DNA sequencing identified a novel homozygous truncation mutation in MYD88 that abolishes MyD88 expression. The patient's dermal fibroblasts had severely impaired IL-6 production after stimulation with ligands for the MyD88-dependent receptors TLR2, TLR4 and IL-1R, while responses to ligands for the MyD88-independent receptors TLR3 and TNF-α were preserved. Notably, secretion of TNF-α, which is essential for BCG control, was also impaired after LPS stimulation. In this first report of BCG infection in MyD88 deficiency, data suggest that MyD88-dependent TNF-α production contributes to control of mycobacterial disease.
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http://dx.doi.org/10.1016/j.clim.2019.07.004DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6736735PMC
October 2019

A novel variant in STAT2 presenting with hemophagocytic lymphohistiocytosis.

J Allergy Clin Immunol 2019 08 15;144(2):611-613.e3. Epub 2019 May 15.

Division of Immunology, Boston Children's Hospital and Harvard Medical School, Boston, Mass. Electronic address:

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http://dx.doi.org/10.1016/j.jaci.2019.05.008DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6688952PMC
August 2019

Immunodeficiency and EBV-induced lymphoproliferation caused by 4-1BB deficiency.

J Allergy Clin Immunol 2019 08 11;144(2):574-583.e5. Epub 2019 Mar 11.

Division of Immunology, Boston Children's Hospital, and the Department of Pediatrics, Harvard Medical School, Boston, Mass. Electronic address:

Background: The tumor TNF receptor family member 4-1BB (CD137) is encoded by TNFRSF9 and expressed on activated T cells. 4-1BB provides a costimulatory signal that enhances CD8 T-cell survival, cytotoxicity, and mitochondrial activity, thereby promoting immunity against viruses and tumors. The ligand for 4-1BB is expressed on antigen-presenting cells and EBV-transformed B cells.

Objective: We investigated the genetic basis of recurrent sinopulmonary infections, persistent EBV viremia, and EBV-induced lymphoproliferation in 2 unrelated patients.

Methods: Whole-exome sequencing, immunoblotting, immunophenotyping, and in vitro assays of lymphocyte and mitochondrial function were performed.

Results: The 2 patients shared a homozygous G109S missense mutation in 4-1BB that abolished protein expression and ligand binding. The patients' CD8 T cells had reduced proliferation, impaired expression of IFN-γ and perforin, and diminished cytotoxicity against allogeneic and HLA-matched EBV-B cells. Mitochondrial biogenesis, membrane potential, and function were significantly reduced in the patients' activated T cells. An inhibitory antibody against 4-1BB recapitulated the patients' defective CD8 T-cell activation and cytotoxicity against EBV-infected B cells in vitro.

Conclusion: This novel immunodeficiency demonstrates the critical role of 4-1BB costimulation in host immunity against EBV infection.
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http://dx.doi.org/10.1016/j.jaci.2019.03.002DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6688916PMC
August 2019

Calm in the midst of cytokine storm: a collaborative approach to the diagnosis and treatment of hemophagocytic lymphohistiocytosis and macrophage activation syndrome.

Pediatr Rheumatol Online J 2019 Feb 14;17(1). Epub 2019 Feb 14.

Division of Immunolgy, Boston Children's Hospital, Boston, MA, USA.

Background: Hemophagocytic lymphohistiocytosis (HLH) and macrophage activation syndrome (MAS) were historically thought to be distinct entities, often managed in isolation. In fact, these conditions are closely related. A collaborative approach, which incorporates expertise from subspecialties that previously treated HLH/MAS independently, is needed. We leveraged quality improvement (QI) techniques in the form of an Evidence-Based Guideline (EBG) to build consensus across disciplines on the diagnosis and treatment of HLH/MAS.

Methods: A multidisciplinary work group was convened that met monthly to develop the HLH/MAS EBG. Literature review and expert opinion were used to develop a management strategy for HLH/MAS. The EBG was implemented, and quality metrics were selected to monitor outcomes.

Results: An HLH/MAS clinical team was formed with representatives from subspecialties involved in the care of patients with HLH/MAS. Broad entry criteria for the HLH/MAS EBG were established and included fever and ferritin ≥500 ng/mL. The rheumatology team was identified as the "gate-keeper," charged with overseeing the diagnostic evaluation recommended in the EBG. First-line medications were recommended based on the acuity of illness and risk of concurrent infection. Quality metrics to be tracked prospectively based on time to initiation of treatment and clinical response were selected.

Conclusion: HLH/MAS are increasingly considered to be a spectrum of related conditions, and joint management across subspecialties could improve patient outcomes. Our experience in creating a multidisciplinary approach to HLH/MAS management can serve as a model for care at other institutions.
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http://dx.doi.org/10.1186/s12969-019-0309-6DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6376762PMC
February 2019

Upper GI biopsies for adenocarcinoma - how many biopsies should endoscopists take?

Histopathology 2019 May 1;74(6):959-963. Epub 2019 Apr 1.

Department of Gastroenterology, Nottingham Digestive Diseases BRC, Nottingham University Hospitals, Nottingham, UK.

Aims: There is evidence that four or five gastric cancer biopsies are required for accurate HER2 interpretation. However, the number of biopsies that need to be taken to reach this number of viable cancer biopsies is without evidence. This study aimed to address this gap by assessing the number of biopsies required to gain at least four viable biopsies containing cancer.

Methods And Results: A total of 105 consecutive biopsy cases of gastric and oesophageal adenocarcinoma were retrieved from files. Only definite cancer diagnoses were included; missed cancers or unproven cases were not considered. The cases were reviewed and the number of biopsies taken, and the number containing viable tumour was recorded. In total, 667 biopsies were taken, of which 471 had viable tumour (70.6%). Seventy of 105 cases (67%) had four viable tumour biopsies, but only 47 of 105 (45%) had five viable tumour biopsies. In order to have a >90% chance of having four viable tumour biopsies, seven needed to be taken, while 10 or more were required for a >90% chance of five viable tumour biopsies. Mathematically, using a 0.7 probability for a single biopsy, eight biopsies would be required for a 94% chance of at least four viable tumour biopsies.

Conclusion: In our large upper GI cancer centre, many biopsy cases do not contain sufficient material for adequate HER2 assessment. In order to meet the four-biopsy requirement for adequate HER2 assessment in >90% of cases, at least eight biopsies need to be taken, while 10 biopsies would be required for the 5-cancer biopsy threshold.
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http://dx.doi.org/10.1111/his.13816DOI Listing
May 2019

Deficient LRRC8A-dependent volume-regulated anion channel activity is associated with male infertility in mice.

JCI Insight 2018 08 23;3(16). Epub 2018 Aug 23.

Department of Epigenetics and Molecular Carcinogenesis, The University of Texas MD Anderson Cancer Center, Smithville, Texas, USA.

Ion channel-controlled cell volume regulation is of fundamental significance to the physiological function of sperm. In addition to volume regulation, LRRC8A-dependent volume-regulated anion channel (VRAC) activity is involved in cell cycle progression, insulin signaling, and cisplatin resistance. Nevertheless, the contribution of LRRC8A and its dependent VRAC activity in the germ cell lineage remain unknown. By utilizing a spontaneous Lrrc8a mouse mutation (c.1325delTG, p.F443*) and genetically engineered mouse models, we demonstrate that LRRC8A-dependent VRAC activity is essential for male germ cell development and fertility. Lrrc8a-null male germ cells undergo progressive degeneration independent of the apoptotic pathway during postnatal testicular development. Lrrc8a-deficient mouse sperm exhibit multiple morphological abnormalities of the flagella (MMAF), a feature commonly observed in the sperm of infertile human patients. Importantly, we identified a human patient with a rare LRRC8A hypomorphic mutation (c.1634G>A, p.Arg545His) possibly linked to Sertoli cell-only syndrome (SCOS), a male sterility disorder characterized by the loss of germ cells. Thus, LRRC8A is a critical factor required for germ cell development and volume regulation in the mouse, and it might serve as a novel diagnostic and therapeutic target for SCOS patients.
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http://dx.doi.org/10.1172/jci.insight.99767DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6141173PMC
August 2018

Phenotype, penetrance, and treatment of 133 cytotoxic T-lymphocyte antigen 4-insufficient subjects.

J Allergy Clin Immunol 2018 12 4;142(6):1932-1946. Epub 2018 May 4.

Department of Immunology, University Hospital Motol and 2nd Faculty of Medicine, Charles University in Prague, Prague, Czech Republic.

Background: Cytotoxic T-lymphocyte antigen 4 (CTLA-4) is a negative immune regulator. Heterozygous CTLA4 germline mutations can cause a complex immune dysregulation syndrome in human subjects.

Objective: We sought to characterize the penetrance, clinical features, and best treatment options in 133 CTLA4 mutation carriers.

Methods: Genetics, clinical features, laboratory values, and outcomes of treatment options were assessed in a worldwide cohort of CTLA4 mutation carriers.

Results: We identified 133 subjects from 54 unrelated families carrying 45 different heterozygous CTLA4 mutations, including 28 previously undescribed mutations. Ninety mutation carriers were considered affected, suggesting a clinical penetrance of at least 67%; median age of onset was 11 years, and the mortality rate within affected mutation carriers was 16% (n = 15). Main clinical manifestations included hypogammaglobulinemia (84%), lymphoproliferation (73%), autoimmune cytopenia (62%), and respiratory (68%), gastrointestinal (59%), or neurological features (29%). Eight affected mutation carriers had lymphoma, and 3 had gastric cancer. An EBV association was found in 6 patients with malignancies. CTLA4 mutations were associated with lymphopenia and decreased T-, B-, and natural killer (NK) cell counts. Successful targeted therapies included application of CTLA-4 fusion proteins, mechanistic target of rapamycin inhibitors, and hematopoietic stem cell transplantation. EBV reactivation occurred in 2 affected mutation carriers after immunosuppression.

Conclusions: Affected mutation carriers with CTLA-4 insufficiency can present in any medical specialty. Family members should be counseled because disease manifestation can occur as late as 50 years of age. EBV- and cytomegalovirus-associated complications must be closely monitored. Treatment interventions should be coordinated in clinical trials.
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http://dx.doi.org/10.1016/j.jaci.2018.02.055DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6215742PMC
December 2018

A quality improvement initiative to increase access to food challenges.

Pediatr Allergy Immunol 2018 06 2;29(4):447-449. Epub 2018 May 2.

Division of Immunology, Boston Children's Hospital, Boston, MA, USA.

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http://dx.doi.org/10.1111/pai.12882DOI Listing
June 2018

Clinical, immunologic, and genetic spectrum of 696 patients with combined immunodeficiency.

J Allergy Clin Immunol 2018 04 12;141(4):1450-1458. Epub 2017 Sep 12.

Acquired Immunodeficiency Research Center, Al-Zahra Hospital, Isfahan University of Medical Sciences, Isfahan, Iran.

Background: Combined immunodeficiencies (CIDs) are diseases of defective adaptive immunity with diverse clinical phenotypes. Although CIDs are more prevalent in the Middle East than Western countries, the resources for genetic diagnosis are limited.

Objectives: This study aims to characterize the categories of patients with CIDs in Iran clinically and genetically.

Methods: Clinical and laboratory data were obtained from 696 patients with CIDs. Patients were subdivided into those with syndromic (344 patients) and nonsyndromic (352 patients) CIDs. Targeted DNA sequencing was performed on 243 (34.9%) patients.

Results: The overall diagnostic yield of the 243 sequenced patients was 77.8% (189 patients). The clinical diagnosis of hyper-IgE syndrome (P < .001), onset of disease at greater than 5 years (P = .02), and absence of multiple affected family members (P = .04) were significantly more frequent in the patients without a genetic diagnosis. An autosomal recessive disease was found in 62.9% of patients, reflecting the high rate of consanguinity in this cohort. Mutations impairing VDJ recombination and DNA repair were the most common underlying causes of CIDs. However, in patients with syndromic CIDs, autosomal recessive mutations in ataxia-telangiectasia mutated (ATM), autosomal dominant mutations in signal transducer and activator of transcription 3 (STAT3), and microdeletions in 22q11.21 were the most commonly affected genomic loci. Patients with syndromic CIDs had a significantly lower 5-year survival rate rather than those with nonsyndromic CIDs.

Conclusions: This study provides proof of principle for the application of targeted next-generation sequencing panels in countries with limited diagnostic resources. The effect of genetic diagnosis on clinical care requires continued improvements in therapeutic resources for these patients.
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http://dx.doi.org/10.1016/j.jaci.2017.06.049DOI Listing
April 2018

Combined immunodeficiency with EBV positive B cell lymphoma and epidermodysplasia verruciformis due to a novel homozygous mutation in RASGRP1.

Clin Immunol 2017 10 16;183:142-144. Epub 2017 Aug 16.

Division of Immunology, Boston Children's Hospital, Harvard Medical School, Boston, MA, United States. Electronic address:

RASGRP1 is a guanine-nucleotide-exchange factor essential for MAP-kinase mediated signaling in lymphocytes. We report the second case of RASGRP1 deficiency in a patient with a homozygous nonsense mutation in the catalytic domain of the protein. The patient had epidermodysplasia verruciformis, suggesting a clinically important intrinsic T cell function defect. Like the previously described patient, our proband also presented with CD4 T cell lymphopenia, impaired T cell proliferation to mitogens and antigens, reduced NK cell function, and EBV-associated lymphoma. The severity of the disease and the development of EBV lymphoma in both patients suggest that hematopoietic stem cell transplantation should be performed rapidly in patients with RASGRP1 deficiency.
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http://dx.doi.org/10.1016/j.clim.2017.08.007DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5673555PMC
October 2017

Exaggerated follicular helper T-cell responses in patients with LRBA deficiency caused by failure of CTLA4-mediated regulation.

J Allergy Clin Immunol 2018 03 7;141(3):1050-1059.e10. Epub 2017 Jun 7.

Division of Immunology, Boston Children's Hospital, and the Department of Pediatrics, Harvard Medical School, Boston, Mass. Electronic address:

Background: LPS-responsive beige-like anchor protein (LRBA) and cytotoxic T lymphocyte-associated antigen 4 (CTLA4) deficiencies give rise to overlapping phenotypes of immune dysregulation and autoimmunity, with dramatically increased frequencies of circulating follicular helper T (cT) cells.

Objective: We sought to determine the mechanisms of cT cell dysregulation in patients with LRBA deficiency and the utility of monitoring cT cells as a correlate of clinical response to CTLA4-Ig therapy.

Methods: cT cells and other lymphocyte subpopulations were characterized. Functional analyses included in vitro follicular helper T (T) cell differentiation and cT/naive B-cell cocultures. Serum soluble IL-2 receptor α chain levels and in vitro immunoglobulin production by cultured B cells were quantified by using ELISA.

Results: cT cell frequencies in patients with LRBA or CTLA4 deficiency sharply decreased with CTLA4-Ig therapy in parallel with other markers of immune dysregulation, including soluble IL-2 receptor α chain, CD45ROCD4 effector T cells, and autoantibodies, and this was predictive of favorable clinical responses. cT cells in patients with LRBA deficiency were biased toward a T1-like cell phenotype, which was partially reversed by CTLA4-Ig therapy. LRBA-sufficient but not LRBA-deficient regulatory T cells suppressed in vitro T cell differentiation in a CTLA4-dependent manner. LRBA-deficient T cells supported in vitro antibody production by naive LRBA-sufficient B cells.

Conclusions: cT cell dysregulation in patients with LRBA deficiency reflects impaired control of T cell differentiation because of profoundly decreased CTLA4 expression on regulatory T cells and probably contributes to autoimmunity in patients with this disease. Serial monitoring of cT cell frequencies is highly useful in gauging the clinical response of LRBA-deficient patients to CTLA4-Ig therapy.
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http://dx.doi.org/10.1016/j.jaci.2017.05.022DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5743769PMC
March 2018

The LRRC8A Mediated "Swell Activated" Chloride Conductance Is Dispensable for Vacuolar Homeostasis in Neutrophils.

Front Pharmacol 2017 12;8:262. Epub 2017 May 12.

Division of Medicine, University College LondonLondon, UK.

The dialysis of human and mouse neutrophils in patch clamp experiments in the conventional whole-cell mode induces the emergence of a chloride (Cl) current that appeared to be primarily regulated by cytoplasmic ionic strength. The characteristics of this current resembled that of the classical, and ubiquitous volume-sensitive outwardly rectifying Cl current: strong outward rectification, selectivity sequence of the Eisenman1 type, insensitivity to external pH and strong inhibition by tamoxifen, DCPIB and WW781. We show that this current is essentially supported by the leucine rich repeat containing 8 A (LRRC8A); the naturally occurring LRRC8A truncation mutant in mice drastically reduced Cl conductance in neutrophils. Remarkably, the residual component presents a distinct pharmacology, but appears equally potentiated by reduced ionic strength. We have investigated the role of the LRRC8A-supported current in the ionic homeostasis of the phagosomal compartment. The vacuolar pH, measured using SNARF-1 labeled , normally rises because of NADPH oxidase activity, and this elevation is blocked by certain Cl channel inhibitors. However, the pH rise remains intact in neutrophils from the mice which also demonstrate preserved phagocytic and respiratory burst capacities and normal-sized vacuoles. Thus, the LRRC8A-dependent conductance of neutrophils largely accounts for their "swell activated" Cl current, but is not required for homeostasis of the phagosomal killing compartment.
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http://dx.doi.org/10.3389/fphar.2017.00262DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5427109PMC
May 2017

Leucine-rich repeat containing 8A (LRRC8A)-dependent volume-regulated anion channel activity is dispensable for T-cell development and function.

J Allergy Clin Immunol 2017 Dec 10;140(6):1651-1659.e1. Epub 2017 Feb 10.

Division of Immunology, Boston Children's Hospital, Harvard Medical School, Boston, Mass. Electronic address:

Background: Leucine-rich repeat containing 8A (LRRC8A) is an ubiquitously expressed transmembrane protein with 17 leucine-rich repeats (LRRs) at its C-terminal end and is an essential component of the volume-regulated anion channel (VRAC), which controls cellular volume. A heterozygous mutation in LRRC8A that truncates the 2 terminal LRRs was reported in a patient with agammaglobulinemia and absent B cells and was demonstrated to exert a dominant negative effect on T- and B-cell development in mice. Lrrc8a mice have severely defective T-cell development and function. It is not known whether the T- and B-cell defects caused by LRRC8A deficiency are caused by loss of VRAC activity.

Objective: We sought to determine whether VRAC activity is required for normal T-cell development and function.

Methods: VRAC activity was examined by using patch-clamp analysis. Flow cytometry was used to examine T-cell development. T-cell proliferation, cytokine secretion, and antibody titers were measured by using standard techniques.

Results: We demonstrate that the spontaneous mouse mutant ébouriffé (ebo/ebo) harbors a homozygous 2-bp frameshift mutation in Lrrc8a that truncates the 15 terminal LRRs of LRRC8A. The Lrrc8a mutation does not affect protein expression but drastically diminishes VRAC activity in T cells. ebo/ebo mice share features with Lrrc8a mice that include curly hair, infertility, reduced longevity, and kidney abnormalities. However, in contrast to Lrrc8a mice, ebo/ebo mice have normal T-cell development and function and intact antibody response to T-dependent antigen.

Conclusion: LRRC8A-dependent VRAC activity is dispensable for T-cell development and function.
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http://dx.doi.org/10.1016/j.jaci.2016.12.974DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6170198PMC
December 2017