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1.  Long-term outcomes of 176 patients with X-linked hyper-IgM syndrome treated with or without hematopoietic cell transplantation 
X-linked hyper-IgM syndrome (XHIGM) is a primary immunodeficiency with high morbidity and mortality compared with those seen in healthy subjects. Hematopoietic cell transplantation (HCT) has been considered a curative therapy, but the procedure has inherent complications and might not be available for all patients.
We sought to collect data on the clinical presentation, treatment, and follow-up of a large sample of patients with XHIGM to (1) compare long-term overall survival and general well-being of patients treated with or without HCT along with clinical factors associated with mortality and (2) summarize clinical practice and risk factors in the subgroup of patients treated with HCT.
Physicians caring for patients with primary immunodeficiency diseases were identified through the Jeffrey Modell Foundation, United States Immunodeficiency Network, Latin American Society for Immunodeficiency, and Primary Immune Deficiency Treatment Consortium. Data were collected with a Research Electronic Data Capture Web application. Survival from time of diagnosis or transplantation was estimated by using the Kaplan-Meier method compared with log-rank tests and modeled by using proportional hazards regression.
Twenty-eight clinical sites provided data on 189 patients given a diagnosis of XHIGM between 1964 and 2013; 176 had valid follow-up and vital status information. Sixty-seven (38%) patients received HCT. The average follow-up time was 8.5 ± 7.2 years (range, 0.1–36.2 years). No difference in overall survival was observed between patients treated with or without HCT (P = .671). However, risk associated with HCT decreased for diagnosis years 1987–1995; the hazard ratio was significantly less than 1 for diagnosis years 1995–1999. Liver disease was a significant predictor of overall survival (hazard ratio, 4.9; 95% confidence limits, 2.2–10.8; P < .001). Among survivors, those treated with HCT had higher median Karnofsky/Lansky scores than those treated without HCT (P < .001). Among patients receiving HCT, 27 (40%) had graft-versus-host disease, and most deaths occurred within 1 year of transplantation.
No difference in survival was observed between patients treated with or without HCT across all diagnosis years (1964–2013). However, survivors treated with HCT experienced somewhat greater well-being, and hazards associated with HCT decreased, reaching levels of significantly less risk in the late 1990s. Among patients treated with HCT, treatment at an early age is associated with improved survival. Optimism remains guarded as additional evidence accumulates.
PMCID: PMC5374029  PMID: 27697500
X-linked hyper-IgM syndrome; CD40 ligand; hematopoietic cell transplantation; defects in class-switch recombination; long-term outcomes; primary immunodeficiency; Karnofsky/Lansky scores
2.  Hematopoietic Stem Cell Transplantation for CD3δ deficiency 
CD3δ deficiency is a fatal form of severe combined immunodeficiency which can be cured by hematopoietic stem cell transplantation (HSCT). The presence of a thymus loaded with T cell progenitors in these patients may require special considerations in choosing the regimen of conditioning and the type of HSCT.
To study the outcome of CD3δ deficiency using various modalities of stem cell transplantation.
We analyzed data on 13 patients with CD3δ deficiency who underwent HSCT in 7 centers. HSCT was performed using different sources of donor stem cells as well as various conditioning regimens.
Two patients who received stem cells from matched related donors and survived, both needed substantial conditioning in order to engraft. Only one of six other patients who received a related mismatched donor (MMRD) transplant survived, two of them had no conditioning while the others received various combinations of conditioning regimens.
Three other patients received stem cells from a matched unrelated donor (MUD), survived and enjoyed full immune reconstitution.
Two other patients received unrelated cord blood without conditioning. One of them has had a partial but stable engraftment, while the other engrafted well but is only 12 months after HSCT. We also report here for the first time that patients with CD3δ deficiency can present with typical features of Omenn syndrome.
HSCT is a successful treatment for patients with CD3δ deficiency. The small number of patients in this report prevent definitive statements on the importance of survival factors, but several are suggested: 1) HLA matched donor transplants are associated with superior reconstitution and survival than mismatched donor transplants; 2) substantial conditioning appears necessary; 3) early diagnosis and absence of opportunistic infections.
PMCID: PMC4490832  PMID: 21757226
CD3delta; severe combined immunodeficiency; bone marrow transplant; stem cell transplant; myeloablative conditioning; engraftment
3.  A homozygous mutation in the stem II domain of RNU4ATAC causes typical Roifman syndrome 
NPJ Genomic Medicine  2017;2:23.
Roifman syndrome (OMIM# 616651) is a complex syndrome encompassing skeletal dysplasia, immunodeficiency, retinal dystrophy and developmental delay, and is caused by compound heterozygous mutations involving the Stem II region and one of the other domains of the RNU4ATAC gene. This small nuclear RNA gene is essential for minor intron splicing. The Canadian Centre for Primary Immunodeficiency Registry and Repository were used to derive patient information as well as tissues. Utilising RNA sequencing methodologies, we analysed samples from patients with Roifman syndrome and assessed intron retention. We demonstrate that a homozygous mutation in Stem II is sufficient to cause the full spectrum of features associated with typical Roifman syndrome. Further, we demonstrate the same pattern of aberration in minor intron retention as found in cases with compound heterozygous mutations.
PMCID: PMC5677950
4.  Variants in TRIM22 that Affect NOD2 Signaling Are Associated With Very Early Onset Inflammatory Bowel Disease 
Gastroenterology  2016;150(5):1196-1207.
Background & Aims
Severe forms of inflammatory bowel disease (IBD) that develop in very young children can be caused by variants in a single gene. We performed whole-exome sequence (WES) analysis to identify genetic factors that might cause granulomatous colitis and severe perianal disease, with recurrent bacterial and viral infections, in an infant of consanguineous parents.
We performed targeted WES analysis of DNA collected from the patient and her parents. We validated our findings by a similar analysis of DNA from 150 patients with very early onset IBD not associated with known genetic factors analyzed in Toronto, Oxford, and Munich. We compared gene expression signatures in inflamed vs. non-inflamed intestinal and rectal tissues collected from patients with treatment-resistant Crohn's disease who participated in a trial of ustekinumab. We performed functional studies of identified variants in primary cells from patients and cell culture.
We identified a homozygous variant in the tripartite motif containing 22 gene (TRIM22) of the patient, as well as in 2 patients with a disease similar phenotype. Functional studies showed that the variant disrupted the ability of TRIM22 to regulate nucleotide binding oligomerization domain containing 2 (NOD2)-dependent activation of interferon-beta signaling and NF-κB. Computational studies demonstrated a correlation between the TRIM22–NOD2 network and signaling pathways and genetic factors associated very early onset and adult-onset IBD. The network also associated with antiviral and mycobacterial effectors and markers of inflammation such as fecal calprotectin, c-reactive protein, and Crohn's disease activity index scores.
In WES and targeted exome sequence analyses of an infant with severe IBD, characterized by granulomatous colitis and severe perianal disease, we identified a homozygous variant of TRIM22 that affect the ability of its product to regulate NOD2. Combined computational and functional studies showed that the TRIM22–NOD2 network regulates antiviral and anti-bacterial signaling pathways that contribute to inflammation. Further study of this network could lead to new disease markers and therapeutic targets for patients with very early and adult-onset IBD.
PMCID: PMC4842103  PMID: 26836588
VEOIBD; CDAI; genetics; risk; susceptibility
5.  Canadian Society of Allergy and Clinical Immunology annual scientific meeting 2016 
Alsayegh, Mohammad A. | Alshamali, Hanan | Khadada, Mousa | Ciccolini, Amanda | Ellis, Anne K. | Quint, Diana | Powley, William | Lee, Laurie | Fiteih, Yahya | Baksh, Shairaz | Vliagoftis, Harissios | Gerega, Sebastien K. | Millson, Brad | Charland, Katia | Barakat, Stephane | Sun, Xichun | Jimenez, Ricardo | Waserman, Susan | FitzGerald, Mark J. | Hébert, Jacques | Cognet-Sicé, Josiane | Renahan, Kevin E. | Huq, Saiful | Chooniedass, Rishma | Sawyer, Scott | Pasterkamp, Hans | Becker, Allan | Smith, Steven G. | Zhang, Shiyuan | Jayasundara, Kavisha | Tacon, Claire | Simidchiev, Alex | Nadeau, Gilbert | Gunsoy, Necdet | Mullerova, Hana | Albers, Frank | Kim, Young Woong | Shannon, Casey P. | Singh, Amrit | Neighbour, Helen | Larché, Mark | Tebbutt, Scott J. | Klopp, Annika | Vehling, Lorena | Becker, Allan B. | Subbarao, Padmaja | Mandhane, Piushkumar J. | Turvey, Stuart E. | Sears, Malcolm R. | Azad, Meghan B. | Loewen, Keely | Monchka, Barret | Mahmud, Salaheddin M. | Jong, Geert ‘t | Longo, Cristina | Bartlett, Gillian | Ducharme, Francine M. | Schuster, Tibor | MacGibbon, Brenda | Barnett, Tracie | North, Michelle L. | Brook, Jeff | Lee, Elizabeth | Omana, Vanessa | Thiele, Jenny | Steacy, Lisa M. | Evans, Greg | Diamond, Miriam | Sussman, Gordon L. | Amistani, Yann | Abiteboul, Kathy | Tenn, Mark W. | Yang, ChenXi | Carlsten, Christopher | Conway, Edward M. | Mack, Douglas | Othman, Yasmin | Barber, Colin M. | Kalicinsky, Chrystyna | Burke, Andrea E. | Messieh, Mary | Nair, Parameswaran | Che, Chun T. | Douglas, Lindsay | Liem, Joel | Duan, Lucy | Miller, Charlotte | Dupuis, Pascale | Connors, Lori A. | Fein, Michael N. | Shuster, Joseph | Hadi, Hani | Polk, Brooke | Raje, Nikita | Labrosse, Roxane | Bégin, Philippe | Paradis, Louis | Roches, Anne Des | Lacombe-Barrios, Jonathan | Mishra, Sanju | Lacuesta, Gina | Chiasson, Meredith | Haroon, Babar | Robertson, Kara | Issekutz, Thomas | Leddin, Desmond | Couban, Stephen | Connors, Lori | Roos, Adrienne | Kanani, Amin | Chan, Edmond S. | Schellenberg, Robert | Rosenfield, Lana | Cvetkovic, Anna | Woodward, Kevin | Quirt, Jaclyn | Watson, Wade T. A. | Castilho, Edson | Sullivan, Jennifer A. | Temple, Beverley | Martin, Donna | Cook, Victoria E. | Mills, Christopher | Portales-Casamar, Elodie | Fu, Lisa W. | Ho, Alexander | Zaltzman, Jeffrey | Chen, Lucy | Vadas, Peter | Gabrielli, Sofianne | Clarke, Ann | Eisman, Harley | Morris, Judy | Joseph, Lawrence | LaVieille, Sebastien | Ben-Shoshan, Moshe | Graham, François | Barnes, Charles | Portnoy, Jay | Stagg, Vincent | Simons, Elinor | Lefebvre, Diana | Dai, David | Mandhane, Piushkumar | Sears, Malcolm | Tam, Herman | Simons, F. Estelle R. | Alotaibi, Dhaifallah | Dawod, Bassel | Tunis, Matthew C. | Marshall, Jean | Desjardins, Marylin | Béland, Marianne | Lejtenyi, Duncan | Drolet, Jean-Phillipe | Lemire, Martine | Tsoukas, Christos | Noya, Francisco J.D. | Alizadehfar, Reza | McCusker, Christine T. | Mazer, Bruce D. | Maestre-Batlle, Danay | Gunawan, Evelyn | Rider, Christopher F. | Bølling, Anette K. | Pena, Olga M. | Suez, Daniel | Melamed, Isaac | Hussain, Iftikhar | Stein, Mark | Gupta, Sudhir | Paris, Kenneth | Fritsch, Sandor | Bourgeois, Christelle | Leibl, Heinz | McCoy, Barbara | Noel, Martin | Yel, Leman | Scott, Ori | Reid, Brenda | Atkinson, Adelle | Kim, Vy Hong-Diep | Roifman, Chaim M. | Grunebaum, Eyal | AlSelahi, Eiman | Aleman, Fernando | Oberle, Amber | Trus, Mike | Sussman, Gordon | Kanani, Amin S. | Chambenoi, Olivier | Chiva-Razavi, Sima | Grodecki, Savannah | Joshi, Nikhil | Menikefs, Peter | Holt, David | Pun, Teresa | Tworek, Damian | Hanna, Raphael | Heroux, Delia | Rosenberg, Elli | Stiemsma, Leah | Turvey, Stuart | Denburg, Judah | Mill, Christopher | Teoh, Timothy | Zimmer, Preeti | Avinashi, Vishal | Paina, Mihaela | Darwish Hassan, Ahmed A. | Oliveria, John Paul | Olesovsky, Chris | Gauvreau, Gail | Pedder, Linda | Keith, Paul K. | Plunkett, Greg | Bolner, Michelle | Pourshahnazari, Persia | Stark, Donald | Vostretsova, Kateryna | Moses, Andrew | Wakeman, Andrew | Singer, Alexander | Gerstner, Thomas | Abrams, Elissa | Johnson, Sara F. | Woodgate, Roberta L.
PMCID: PMC5390240
6.  Loss of the Arp2/3 complex component ARPC1B causes platelet abnormalities and predisposes to inflammatory disease 
Nature Communications  2017;8:14816.
Human actin-related protein 2/3 complex (Arp2/3), required for actin filament branching, has two ARPC1 component isoforms, with ARPC1B prominently expressed in blood cells. Here we show in a child with microthrombocytopenia, eosinophilia and inflammatory disease, a homozygous frameshift mutation in ARPC1B (p.Val91Trpfs*30). Platelet lysates reveal no ARPC1B protein and greatly reduced Arp2/3 complex. Missense ARPC1B mutations are identified in an unrelated patient with similar symptoms and ARPC1B deficiency. ARPC1B-deficient platelets are microthrombocytes similar to those seen in Wiskott–Aldrich syndrome that show aberrant spreading consistent with loss of Arp2/3 function. Knockout of ARPC1B in megakaryocytic cells results in decreased proplatelet formation, and as observed in platelets from patients, increased ARPC1A expression. Thus loss of ARPC1B produces a unique set of platelet abnormalities, and is associated with haematopoietic/immune symptoms affecting cell lineages where this isoform predominates. In agreement with recent experimental studies, our findings suggest that ARPC1 isoforms are not functionally interchangeable.
ARPC1B is a component of the actin-related protein 2/3 complex (Arp2/3), which is required for actin filament branching. Kahr et al. show that ARPC1B deficiency in humans is associated with severe multisystem disease that includes platelet abnormalities, eosinophilia, eczema and other indicators of immune disease.
PMCID: PMC5382316  PMID: 28368018
7.  Improving cellular therapy for primary immune deficiency diseases: Recognition, diagnosis, and management 
More than 20 North American academic centers account for the majority of hematopoietic stem cell transplantation (HCT) procedures for primary immunodeficiency diseases (PIDs), with smaller numbers performed at additional sites. Given the importance of a timely diagnosis of these rare diseases and the diversity of practice sites, there is a need for guidance as to best practices in management of patients with PIDs before, during, and in follow-up for definitive treatment. In this conference report of immune deficiency experts and HCT physicians who care for patients with PIDs, we present expert guidance for (1) PID diagnoses that are indications for HCT, including severe combined immunodeficiency disease (SCID), combined immunodeficiency disease, and other non-SCID diseases; (2) the critical importance of a high degree of suspicion of the primary care physician and timeliness of diagnosis for PIDs; (3) the need for rapid referral to an immune deficiency expert, center with experience in HCT, or both for patients with PIDs; (4) medical management of a child with suspicion of SCID/combined immunodeficiency disease while confirming the diagnosis, including infectious disease management and workup; (5) the posttransplantation follow-up visit schedule; (6) antimicrobial prophylaxis after transplantation, including gamma globulin administration; and (7) important indications for return to the transplantation center after discharge. Finally, we discuss the role of high-quality databases in treatment of PIDs and HCTas an element of the infrastructure that will be needed for productive multicenter clinical trials in these rare diseases.
PMCID: PMC2831471  PMID: 20004776
Allogeneic hematopoietic stem cell transplantation; gene therapy; primary immunodeficiency; clinical trial
8.  Novel Combined Immune Deficiency and Radiation Sensitivity Blended Phenotype in an Adult with Biallelic Variations in ZAP70 and RNF168 
With the advent of high-throughput genomic sequencing techniques, novel genetic etiologies are being uncovered for previously unexplained Mendelian phenotypes, and the underlying genetic architecture of disease is being unraveled. Although most of these “mendelizing” disease traits represent phenotypes caused by single-gene defects, a percentage of patients have blended phenotypes caused by pathogenic variants in multiple genes. We describe an adult patient with susceptibility to bacterial, herpesviral, and fungal infections. Immunologic defects included CD8+ T cell lymphopenia, decreased T cell proliferative responses to mitogens, hypogammaglobulinemia, and radiation sensitivity. Whole-exome sequencing revealed compound heterozygous variants in ZAP70. Biallelic mutations in ZAP70 are known to produce a spectrum of immune deficiency that includes the T cell abnormalities observed in this patient. Analyses for variants in genes associated with radiation sensitivity identified the presence of a homozygous RNF168 variant of unknown significance. RNF168 deficiency causes radiosensitivity, immunodeficiency, dysmorphic features, and learning difficulties syndrome and may account for the radiation sensitivity. Thus, the patient was found to have a novel blended phenotype associated with multilocus genomic variation: i.e., separate and distinct genetic defects. These findings further illustrate the clinical utility of applying genomic testing in patients with primary immunodeficiency diseases.
PMCID: PMC5445153
primary immunodeficiency; ZAP70; RNF168; radiosensitivity; immunodeficiency; dysmorphic features; and learning difficulties syndrome; whole-exome sequencing; blended phenotype
9.  Mutations in Plasmalemma Vesicle Associated Protein Result in Sieving Protein-Losing Enteropathy Characterized by Hypoproteinemia, Hypoalbuminemia, and Hypertriglyceridemia 
Background & Aims, Methods
Severe intestinal diseases observed in very young children are often the result of monogenic defects. We used whole exome sequencing (WES) to examine the genetic cause in a patient with a distinct severe form of protein losing enteropathy (PLE) characterized by hypoproteinemia, hypoalbuminemia, and hypertriglyceridemia.
WES was performed at the Centre for Applied Genomics, Hospital for Sick Children, Toronto, Canada. Exome library preparation was performed using the Ion Torrent AmpliSeq RDY Exome Kit. Functional studies were carried out based on the identified mutation.
Using whole exome sequencing we identified a homozygous nonsense mutation (1072C>T; p.Arg358*) in the PLVAP (plasmalemma vesicle associated protein) gene in an infant from consanguineous parents who died at five months of age of severe protein losing enteropathy. Functional studies determined that the mutated PLVAP mRNA and protein were not expressed in the patient biopsy tissues, presumably secondary to nonsense-mediated mRNA decay. Pathological analysis showed that the loss of PLVAP resulted in disruption of endothelial fenestrated diaphragms.
PLVAP p.Arg358* mutation resulted in loss of PLVAP expression with subsequent deletion of the diaphragms of endothelial fenestrae leading to plasma protein extravasation, protein-losing enteropathy and ultimately death.
PMCID: PMC4507283  PMID: 26207260
Protein losing enteropathy; PLE; PLVAP; very early onset IBD; VEOIBD; IBD; endothelium; fenestrae; hypoproteinemia; hypoalbuminemia; and hypertriglyceridemia; monogenic diseases
10.  Compound heterozygous mutations in the noncoding RNU4ATAC cause Roifman Syndrome by disrupting minor intron splicing 
Nature Communications  2015;6:8718.
Roifman Syndrome is a rare congenital disorder characterized by growth retardation, cognitive delay, spondyloepiphyseal dysplasia and antibody deficiency. Here we utilize whole-genome sequencing of Roifman Syndrome patients to reveal compound heterozygous rare variants that disrupt highly conserved positions of the RNU4ATAC small nuclear RNA gene, a minor spliceosome component that is essential for minor intron splicing. Targeted sequencing confirms allele segregation in six cases from four unrelated families. RNU4ATAC rare variants have been recently reported to cause microcephalic osteodysplastic primordial dwarfism, type I (MOPD1), whose phenotype is distinct from Roifman Syndrome. Strikingly, all six of the Roifman Syndrome cases have one variant that overlaps MOPD1-implicated structural elements, while the other variant overlaps a highly conserved structural element not previously implicated in disease. RNA-seq analysis confirms extensive and specific defects of minor intron splicing. Available allele frequency data suggest that recessive genetic disorders caused by RNU4ATAC rare variants may be more prevalent than previously reported.
Roifman Syndrome is a rare disorder whose disease manifestations include growth retardation, spondyloepiphyseal dysplasia and immunodeficiency. Here, the authors use whole-genome sequencing to discover that rare compound heterozygous variants disrupting the small nuclear RNA gene RNU4ATAC cause Roifman Syndrome.
PMCID: PMC4667643  PMID: 26522830
11.  Mutations in Plasmalemma Vesicle Associated Protein Result in Sieving Protein-Losing Enteropathy Characterized by Hypoproteinemia, Hypoalbuminemia, and Hypertriglyceridemia 
Background & Aims
Severe intestinal diseases observed in very young children are often the result of monogenic defects. We used whole-exome sequencing (WES) to examine genetics in a patient with a distinct severe form of protein-losing enteropathy (PLE) characterized by hypoproteinemia, hypoalbuminemia, and hypertriglyceridemia.
WES was performed at the Centre for Applied Genomics, Hospital for Sick Children, Toronto, Canada, and exome library preparation was performed with the Ion Torrent AmpliSeq RDY Exome Kit. Functional studies were based on the identified mutation.
Using WES we identified a homozygous nonsense mutation (1072C>T; p.Arg358*) in the PLVAP (plasmalemma vesicle-associated protein) gene in an infant from consanguineous parents who died at 5 months of age of severe PLE. Functional studies determined that the mutated PLVAP mRNA and protein were not expressed in the patient biopsy tissues, presumably secondary to nonsense-mediated mRNA decay. Pathological analysis showed that the loss of PLVAP resulted in disruption of endothelial fenestrated diaphragms.
The PLVAP p.Arg358* mutation resulted in the loss of PLVAP expression with subsequent deletion of the diaphragms of endothelial fenestrae, which led to plasma protein extravasation, PLE, and ultimately death.
PMCID: PMC4507283  PMID: 26207260
Endothelium; Fenestrae; Hypertriglyceridemia; Hypoalbuminemia; Hypoproteinemia; Very Early Onset Inflammatory Bowel Disease; Monogenic Diseases; Protein-Losing Enteropathy; Whole-Exome Sequencing; BSA, bovine serum albumin; DPBS, Dulbecco’s phosphate-buffered saline; EpCAM, epithelial cell adhesion molecule; HA, human influenza hemagglutinin; hrGFP, humanized Renilla green fluorescent protein; IBD, inflammatory bowel disease; PAS, periodic acid–Schiff; PBS, phosphate-buffered saline; PLE, protein-losing enteropathy; PLVAP, plasmalemma vesicle-associated protein; SDS-PAGE, sodium dodecyl sulfate polyacrylamide gel electrophoresis; TEM, transmission electron microscopy; VEOIBD, very early onset inflammatory bowel disease; VLDL, very-low-density lipoprotein; PCR, polymerase chain reaction; WES, Whole-Exome Sequencing
12.  A Phenotypic Approach for IUIS PID Classification and Diagnosis: Guidelines for Clinicians at the Bedside 
Journal of clinical immunology  2013;33(6):1078-1087.
The number of genetically defined Primary Immunodeficiency Diseases (PID) has increased exponentially, especially in the past decade. The biennial classification published by the IUIS PID expert committee is therefore quickly expanding, providing valuable information regarding the disease-causing genotypes, the immunological anomalies, and the associated clinical features of PIDs. These are grouped in eight, somewhat overlapping, categories of immune dysfunction. However, based on this immunological classification, the diagnosis of a specific PID from the clinician’s observation of an individual clinical and/or immunological phenotype remains difficult, especially for non-PID specialists. The purpose of this work is to suggest a phenotypic classification that forms the basis for diagnostic trees, leading the physician to particular groups of PIDs, starting from clinical features and combining routine immunological investigations along the way.We present 8 colored diagnostic figures that correspond to the 8 PID groups in the IUIS Classification, including all the PIDs cited in the 2011 update of the IUIS classification and most of those reported since.
PMCID: PMC4083684  PMID: 23657403
Primary immunodeficiency; classification; IUIS; diagnosis tool
13.  IL-10R Polymorphisms are Associated with Very Early-Onset Ulcerative Colitis 
Inflammatory bowel diseases  2013;19(1):115-123.
Background and Aims
Interleukin-10 (IL-10) signaling genes are attractive inflammatory bowel disease (IBD) candidate genes as IL-10 restricts intestinal inflammation, IL-10 polymorphisms have been associated with IBD in genome-wide association studies, and mutations in IL-10 and IL-10 receptor (IL-10R) genes have been reported in immunodeficient children with severe infantile-onset IBD. Our objective was to determine if IL-10R polymorphisms were associated with early-onset IBD (EO-IBD) and very early-onset IBD (VEO-IBD).
Candidate-gene analysis of IL10RA and IL10RB was performed after initial sequencing of an infantile onset-IBD patient identified a novel homozygous mutation. The discovery cohort included 188 EO-IBD subjects and 188 healthy subjects. Polymorphisms associated with IBD in the discovery cohort were genotyped in an independent validation cohort of 422 EO-IBD subjects and 480 healthy subjects.
We identified a homozygous, splice-site point mutation in IL10RA in an infantile-onset IBD patient causing a premature stop codon (P206X) and IL-10 insensitivity. IL10RA and IL10RB sequencing in the discovery cohort identified five IL10RA polymorphisms associated with ulcerative colitis (UC) and two IL10RB polymorphisms associated with Crohn’s disease (CD). Of these polymorphisms, two IL10RA SNPs, rs2228054 and rs2228055 were associated with very early-onset UC in the discovery cohort and replicated in an independent validation cohort (OR 3.08, combined p=2×10−4; and OR 2.93, p=6×10−4, respectively).
We identified IL10RA polymorphisms that confer risk for developing VEO-UC. Additionally, we identified the first splice site mutation in IL10RA resulting in infantile-onset IBD. This study expands the phenotype of IL10RA polymorphisms to include both severe arthritis and VEO-UC.
PMCID: PMC3744177  PMID: 22550014
IL-10; IL-10 Receptor; inflammatory bowel disease; immunodeficiency
14.  Human CD3γ, but not CD3δ, haploinsufficiency differentially impairs γδ versus αβ surface TCR expression 
BMC Immunology  2013;14:3.
The T cell antigen receptors (TCR) of αβ and γδ T lymphocytes are believed to assemble in a similar fashion in humans. Firstly, αβ or γδ TCR chains incorporate a CD3δε dimer, then a CD3γε dimer and finally a ζζ homodimer, resulting in TCR complexes with the same CD3 dimer stoichiometry. Partial reduction in the expression of the highly homologous CD3γ and CD3δ proteins would thus be expected to have a similar impact in the assembly and surface expression of both TCR isotypes. To test this hypothesis, we compared the surface TCR expression of primary αβ and γδ T cells from healthy donors carrying a single null or leaky mutation in CD3G (γ+/−) or CD3D (δ+/−, δ+/leaky) with that of normal controls.
Although the partial reduction in the intracellular availability of CD3γ or CD3δ proteins was comparable as a consequence of the mutations, surface TCR expression measured with anti-CD3ε antibodies was significantly more decreased in γδ than in αβ T lymphocytes in CD3γ+/− individuals, whereas CD3δ+/− and CD3δ+/leaky donors showed a similar decrease of surface TCR in both T cell lineages. Therefore, surface γδ TCR expression was more dependent on available CD3γ than surface αβ TCR expression.
The results support the existence of differential structural constraints in the two human TCR isotypes regarding the incorporation of CD3γε and CD3δε dimers, as revealed by their discordant surface expression behaviour when confronted with reduced amounts of CD3γ, but not of the homologous CD3δ chain. A modified version of the prevailing TCR assembly model is proposed to accommodate these new data.
PMCID: PMC3585704  PMID: 23336327
T cells; CD3; Haploinsufficiency
15.  Allogeneic Hematopoietic Cell Transplantation for Primary Immune Deficiency Diseases Current Status and Critical Needs 
Allogeneic hematopoietic cell transplantation (HCT) has been employed for 40 years to ameliorate or cure primary immune deficiency (PID) diseases, including severe combined immune deficiency (SCID) and non-SCID PID. There is a critical need for evaluation of the North American experience of different HCT approaches for these diseases, in order to identify best practices and plan future investigative clinical trials. A conference of experts in HCT treatment of PID has recommended: (1) a comprehensive cross-sectional and retrospective analysis of HCT survivors with SCID; (2) a prospective study of SCID patients receiving HCT, with comparable baseline and follow-up testing across participating centers; (3) a pilot study of newborn screening for SCID to identify affected infants prior to compromise by infection; and (4) for the non-SCID diseases, Wiskott-Aldrich syndrome and Chronic Granulomatous Disease, studies of the natural history of disease in patients who do or do not receive HCT. To accomplish these goals, collaboration by a consortium of institutions in North America is proposed. Participation of immunologists and HCT physicians having interest in PID and experts in laboratory methods, clinical outcomes assessment, databases and analysis will be required for the success of these studies.
PMCID: PMC3357108  PMID: 18992926
Allogeneic hematopoietic cell transplantation; primary immunodeficiency; clinical trial
16.  Primary Immunodeficiency Diseases: An Update on the Classification from the International Union of Immunological Societies Expert Committee for Primary Immunodeficiency 
We report the updated classification of primary immunodeficiency diseases, compiled by the ad hoc Expert Committee of the International Union of Immunological Societies. As compared to the previous edition, more than 15 novel disease entities have been added in the updated version. For each disorders, the key clinical and laboratory features are provided. This updated classification is meant to help in the diagnostic approach to patients with these diseases.
PMCID: PMC3342372  PMID: 22566844
primary immunodeficiency diseases
17.  Mitochondrial Basis for Immune Deficiency 
The Journal of Experimental Medicine  2000;191(12):2197-2208.
We generated purine nucleoside phosphorylase (PNP)-deficient mice to gain insight into the mechanism of immune deficiency disease associated with PNP deficiency in humans. Similar to the human disease, PNP deficiency in mice causes an immunodeficiency that affects T lymphocytes more severely than B lymphocytes. PNP knockout mice exhibit impaired thymocyte differentiation, reduced mitogenic and allogeneic responses, and decreased numbers of maturing thymocytes and peripheral T cells. T lymphocytes of PNP-deficient mice exhibit increased apoptosis in vivo and higher sensitivity to gamma irradiation in vitro. We propose that the immune deficiency in PNP deficiency is a result of inhibition of mitochondrial DNA repair due to the accumulation of dGTP in the mitochondria. The end result is increased sensitivity of T cells to spontaneous mitochondrial DNA damage, leading to T cell depletion by apoptosis.
PMCID: PMC2193200  PMID: 10859343
immune deficiency; apoptosis; mitochondria; purine metabolism; T lymphocyte

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