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The recognition that cytosolic mtDNA activates cGAS-STING innate immune signaling has unlocked novel disease mechanisms. Here, an uncharacterized variant predicted to affect TOP1MT function, P193L, was discovered in a family with multiple early-onset autoimmune diseases, including Systemic Lupus Erythematosus (SLE). Although there was no previous genetic association betweenTOP1MTand autoimmune disease, the role of TOP1MT as a regulator of mtDNA led us to investigate whether TOP1MT could mediate the release of mtDNA to the cytosol, where it could then activate the cGAS-STING innate immune pathway known to be activated in SLE and other autoimmune diseases. Through analysis of cells with reduced TOP1MT expression, we show that loss of TOP1MT results in release of mtDNA to the cytosol, which activates the cGAS-STING pathway. We also characterized the P193L variant for its ability to rescue several TOP1MT functions when expressed inTOP1MTknockout cells. We show that the P193L variant is not fully functional, as its re-expression at high levels was unable to rescue mitochondrial respiration deficits, and only showed partial rescue for other functions, including repletion of mtDNA replication following depletion, nucleoid size, steady state mtDNA transcripts levels, and mitochondrial morphology. Additionally, expression of P193L at endogenous levels was unable to rescue mtDNA release-mediated cGAS-STING signaling. Overall, we report a link between TOP1MT and mtDNA release leading to cGAS-STING activation. Moreover, we show that the P193L variant has partial loss of function that may contribute to autoimmune disease susceptibility via cGAS-STING mediated activation of the innate immune system.

Purpose of review Primary sclerosing cholangitis (PSC) is a progressive biliary liver disorder strongly associated with inflammatory bowel disease (PSC-IBD). We summarize the genetics of PSC-IBD and highlight recent findings that further differentiate PSC-IBD as a unique disease. Recent findings To date, genome-wide studies have uncovered 23 susceptibility loci for PSC-IBD, the majority of which have been previously reported as risk factors in other immune-mediated disorders. For most candidates, the pathological relationship to PSC-IBD remains largely unknown. Several candidate genes appear to be liver related but the large majority relate to immunity and reaffirm that alterations to immune function, trafficking, and tolerance are likely to influence susceptibility and presentation of PSC-IBD. Similar to most immune-mediated diseases, the strongest association in PSC-IBD resides within the human leukocyte antigen complex and suggests that disease-specific antigens drive pathogenic immune responses. Although genetic predisposition influences disease, genetic determinants account for less than 10% of total disease liability in PSC-IBD, clearly emphasizing the predominant role of environmental factors on disease susceptibility. Summary Genetic studies define PSC-IBD as a unique disease to IBD mirroring clinical observations. Most risk loci harbour immune-related genes and disease variants are likely to perturb immune function, tolerance, and/or trafficking. Additional studies in patients and novel experimental systems are needed to identify the origin and impact of environmental factors in relation to genetic predisposition in PSC-IBD.

Background: Over the last 50 years, genetic studies have uncovered a spectrum of rare and common alleles that confer susceptibility to both Mendelian and complex forms of liver disease. For disorders of Mendelian inheritance, identification of the causal variants has demonstrated that common environmental exposures can elicit severe liver pathogenesis in predisposed individuals. Specific environmental triggers for complex liver disorders are largely unknown; however, large-scale association studies indicate that environmental triggers are the predominant factors in driving liver pathophysiology. Key Messages: In Mendelian liver disorders, a single rare variant of major effect is often responsible for disease development. Gene-sequencing technologies have greatly facilitated the discovery of causal variants for Mendelian diseases and are increasingly utilized in molecular and clinical genetics for diagnostic and counselling purposes. By contrast, genetic susceptibility for complex liver disorders is heterogeneous, as many different genes acting on multiple distinct pathways influence disease onset and severity. Risk variants for complex liver disorders are relatively common, typically of small effect size and detected by genome-wide association studies (GWAS), which compare the genetic variation of specific loci using thousands of patients and healthy controls. Thus far, GWAS have detected dozens of unique and overlapping risk alleles for complex liver disease, but these account for less than a quarter of the overall disease liability. These observations emphasize that environmental exposures on a background of genetic predisposition are significant drivers of liver pathophysiology. Rare variants of large effect size, undetectable by GWAS, may also affect the development of complex disease on a case-to-case basis but evidence for such a scenario remains to be determined. Conclusions: Genetic technologies have identified numerous risk genes for Mendelian and complex liver disorders transforming disease recognition. For complex liver disorders, deciphering the interplay between genetic risk and environment determinants remains a significant challenge for unlocking the development of novel and personalized interventions.

Background Systemic sclerosis (SSc) is a progressive, multi organ, auto-immune disease marked by frequent and severe gastrointestinal (GI) afflictions and gut dysbiosis. Objectives Determine the safety and efficacy of fecal microbiota transplantation (FMT) using commercially-available anaerobic cultivated human intestinal microbiota (ACHIM) in patients with SSc. Methods The trial was a single-center, randomized, double-blind, placebo-controlled 16-week pilot of FMT by gastroduodenoscopy of ACHIM in SSc conducted at Oslo University Hospital. Primary endpoints were safety and clinical efficacy on GI symptoms assessed at weeks 4 and 16. Safety was assessed by observation, interviews and standardized safety form. Efficacy on GI symptoms was measured using the UCLA GIT 2.0 score questionnaire. Patients were defined as responders if reported symptom improvement was equivalent to the UCLA GIT definition of “minimally clinically important difference”. Secondary and explorative endpoints included changes in relative abundance of total, immunoglobulin (Ig)A- and IgM-coated fecal bacteria measured by 16s rRNA sequencing; changes in modified Rodnan skin score, lung function, CRP, ESR, and patient and physician global. Descriptive statistics were applied for clinical endpoints and linear mixed models for microbial analysis. Results Ten patients with limited cutaneous SSc randomized to ACHIM (n=5) or placebo (n=5) were included. All patients were female with clinical apparent GI symptoms, mean age of 62 years and mean time from diagnosis of 12 yrs. Two placebo controls experienced procedure-related serious adverse events; one developed laryngospasms at first gastroduodenoscopy necessitating study exclusion, one duodenal perforation at final gastroduodenoscopy. Improvement in total GIT score was reported by 3/5 FMT patients compared to 2/4 placebo controls at weeks 4 and 16 (Figure 1). FMT effects were most pronounced on lower GI symptoms, with improvement reported by 5/5 FMT patients with diarrhea, distention/bloating and/or fecal incontinence at baseline compared to 2/4 placebo controls (Figure). Clinical secondary endpoints showed no differences and other side effects (stomach discomfort, bloating and diarrhea) were mild and transient. Fecal microbiota diversity (observed number of operational taxonomic units) was increased after FMT compared to placebo treatment at week 16 (p Conclusion FMT of commercially-available ACHIM in patients with SSc appeared safe, effectively reduced lower GI symptoms, altered gut microbiota composition, richness and diversity and appeared to affect the mucosal immune system Disclosure of Interests Anna-Maria Hoffmann-Vold Grant/research support from: Received research funding or other remuneration from Boehringer Ingelheim, GSK, and Actelion, Consultant for: Received consulting fees or other remuneration from Boehringer Ingelheim, GSK, and Actelion, Speakers bureau: Actelion and Boehringer Ingelheim, Havard Fretheim Consultant for: Received consulting fees or other remuneration from GSK, and Actelion, Brian K Chung: None declared, Henriette Didriksen Consultant for: Received consulting fees or other remuneration from GSK, and Actelion, Espen S Baekkevold: None declared, Oyvind Midtvedt: None declared, Cathrine Brunborg: None declared, Torhild Garen: None declared, Tore Midtvedt Shareholder of: Owner of ACHIM, Johannes R Hov: None declared, Knut EA Lundin: None declared, Oyvind Molberg: None declared

Background Despite recent advances in the diagnosis and understanding of many autoinflammatory diseases, there are still a great number of patients with phenotypes that do not fit any clinically- and/or genetically-defined disorders. Case presentation We describe a fourteen-year-old boy who presented at two and a half years of age with recurrent febrile episodes. Over the course of the disease, the episodes increased in frequency and severity, with new signs and symptoms continuing to appear. Most importantly, these included skin changes, splenomegaly and transaminitis. Only partial control of the disease was achieved with anti-IL-1 therapy. Extensive investigation showed generalized inflammation without immune deficiency, with increased levels of serum amyloid A and several pro-inflammatory cytokines including interferon-γ, as well as an increased type I interferon score. Exome sequence analysis identified P369S and R408Q variants in the MEFV innate immunity regulator, pyrin (MEFV) gene and T260 M and T320 M variants in the NLR family pyrin domain containing 12 (NLRP12) gene. Conclusion Patients with unclassified and/or unexplained autoinflammatory syndromes present diagnostic and therapeutic challenges and collectively form a substantial part of every cohort of patients with autoinflammatory diseases. Therefore, it is important to acquire their full genomic profile through whole exome and/or genome sequencing and present their cases to a broader audience, to facilitate characterization of similar patients. A critical mass of well-characterized cases will lead to improved diagnosis and informed treatment.

Objectives Systemic sclerosis (SSc) is an auto-immune, multi organ disease marked by severe gastrointestinal (GI) involvement and gut dysbiosis. Here, we aimed to determine the safety and efficacy of fecal microbiota transplantation (FMT) using commercially-available anaerobic cultivated human intestinal microbiota (ACHIM) in SSc. Methods Ten patients with SSc were randomized to ACHIM (n = 5) or placebo (n = 5) in a double-blind, placebo-controlled 16-week pilot. All patients had mild to severe upper and lower GI symptoms including diarrhea, distention/bloating and/or fecal incontinence at baseline. Gastroduodenoscopy transfer of ACHIM or placebo was performed at weeks 0 and 2. Primary endpoints were safety and clinical efficacy on GI symptoms assessed at weeks 4 and 16. Secondary endpoints included changes in relative abundance of total, immunoglobulin (Ig) A- and IgM-coated fecal bacteria measured by 16s rRNA sequencing. Results ACHIM side effects were mild and transient. Two placebo controls experienced procedure-related serious adverse events; one developed laryngospasms at week 0 gastroduodenoscopy necessitating study exclusion whilst one encountered duodenal perforation during gastroduodenoscopy at the last study visit (week 16). Decreased bloating, diarrhea and/or fecal incontinence was observed in four of five patients in the FMT group (week 4 or/and 16) and in two of four in the placebo group (week 4 or 16). Relative abundance, richness and diversity of total and IgA-coated and IgM-coated bacteria fluctuated more after FMT, than after placebo. Conclusions FMT of commercially-available ACHIM is associated with gastroduodenoscopy complications but reduces lower GI symptoms by possibly altering the gut microbiota in patients with SSc.

Primary biliary cirrhosis (PBC), primary sclerosing cholangitis (PSC) and autoimmune hepatitis (AIH) have collectively been recognized as autoimmune liver diseases. They have all been subjected to genome-wide association studies (GWAS) and several dozens susceptibility loci have been determined. The predominant feature of the genetic findings is that of a strong association with the human leukocyte antigen (HLA) and numerous weak associations scattered throughout the remainder of the genome. The non-HLA associations show some degree of overlap, not only between PBC, PSC and AIH, but also with other autoimmune and immune-mediated diseases. Mathematical modelling shows that the main fraction of autoimmune disease risk (including that of autoimmune liver diseases) is not explained by GWAS, proposing a major role of environmental factors. The HLA associations and autoantibodies observed in these conditions may hold clues as to the nature of such factors, which are exceedingly difficult to map by means of epidemiological study designs. The present review article explores the potential relationship between genetic risk as determined by GWAS and environmental risk in autoimmune liver diseases, and proposes a model for relevant thinking on the susceptibility genes in PBC, PSC and AIH.

Primary sclerosing cholangitis (PSC) is an idiopathic cholangiopathy strongly associated with inflammatory bowel disease (IBD) and characterized by cholestasis, chronic immune infiltration and progressive fibrosis of the intrahepatic and extrahepatic bile ducts. PSC confers a high risk of cholangiocarcinoma (CCA) with PSC-CCA representing the leading cause of PSC-associated mortality. PSC-CCA is derived from cholangiocytes and associated progenitor cells - a heterogeneous group of dynamic epithelial cells lining the biliary tree that modulate the composition and volume of bile production by the liver. Infection, inflammation and cholestasis can trigger cholangiocyte activation leading to an increased expression of adhesion and antigen-presenting molecules as well as the release of various inflammatory and fibrogenic mediators. As a result, activated cholangiocytes engage in a myriad of cellular processes, including hepatocellular proliferation, apoptosis, angiogenesis and fibrosis. Cholangiocytes can also regulate the recruitment of immune cells, mesenchymal cells, and endothelial cells that participate in tissue repair and destruction in settings of persistent inflammation. In PSC, the role of cholangiocytes and the mechanisms governing their transformation to PSC-CCA are unclear however localization of disease suggests that cholangiocytes are a key target and potential regulator of hepatobiliary immunity, fibrogenesis and tumorigenesis. Herein, we summarize mechanisms of cholangiocyte activation in PSC and highlight new insights into disease pathways that may contribute to the development of PSC-CCA. This article is part of a Special Issue entitled: Cholangiocytes in Health and Disease edited by Jesus Banales, Marco Marzioni, Nicholas LaRusso and Peter Jansen.

ObjectiveWe sought to conduct a major objective of the CAEP Academic Section, an environmental scan of the academic emergency medicine programs across the 17 Canadian medical schools.MethodsWe developed an 84-question questionnaire, which was distributed to academic heads. The responses were validated by phone by the lead author to ensure that the questions were answered completely and consistently. Details of pediatric emergency medicine units were excluded from the scan.ResultsAt eight of 17 universities, emergency medicine has full departmental status and at two it has no official academic status. Canadian academic emergency medicine is practiced at 46 major teaching hospitals and 13 specialized pediatric hospitals. Another 69 Canadian hospital EDs regularly take clinical clerks and emergency medicine residents. There are 31 full professors of emergency medicine in Canada. Teaching programs are strong with clerkships offered at 16/17 universities, CCFP(EM) programs at 17/17, and RCPSC residency programs at 14/17. Fourteen sites have at least one physician with a Master’s degree in education. There are 55 clinical researchers with salary support at 13 universities. Sixteen sites have published peer-reviewed papers in the past five years, ranging from four to 235 per site. Annual budgets range from $200,000 to $5,900,000.ConclusionThis comprehensive review of academic activities in emergency medicine across Canada identifies areas of strengths as well as opportunities for improvement. CAEP and the Academic Section hope we can ultimately improve ED patient care by sharing best academic practices and becoming better teachers, educators, and researchers.

Individuals with X-linked lymphoproliferative disease lack invariant natural killer T (iNKT) cells and are exquisitely susceptible to Epstein-Barr virus (EBV) infection. To determine whether iNKT cells recognize or regulate EBV, resting B cells were infected with EBV in the presence or absence of iNKT cells. The depletion of iNKT cells increased both viral titers and the frequency of EBV-infected B cells. However, EBV-infected B cells rapidly lost expression of the iNKT cell receptor ligand CD1d, abrogating iNKT cell recognition. To determine whether induced CD1d expression could restore iNKT recognition in EBV-infected cells, lymphoblastoid cell lines (LCL) were treated with AM580, a synthetic retinoic acid receptor-α agonist that upregulates CD1d expression via the nuclear protein, lymphoid enhancer-binding factor 1 (LEF-1). AM580 significantly reduced LEF-1 association at the CD1d promoter region, induced CD1d expression on LCL, and restored iNKT recognition of LCL. CD1d-expressing LCL elicited interferon γ secretion and cytotoxicity by iNKT cells even in the absence of exogenous antigen, suggesting an endogenous iNKT antigen is expressed during EBV infection. These data indicate that iNKT cells may be important for early, innate control of B cell infection by EBV and that downregulation of CD1d may allow EBV to circumvent iNKT cell-mediated immune recognition.

Royal College of Physicians and Surgeons (RCPS) emergency medicine (EM) residents must complete a scholarly project; however, significant variation exists in Canadian EM resident research education and facilitation. We developed and implemented a novel mandatory research education rotation for RCPS EM residents intended to increase knowledge, faculty/resident collaborations, and, ultimately, scholarly output. This 4-week rotation took place in the fall of 2011 and consisted of 37 faculty-led didactic, critical appraisal, and workshop seminars. Exposure to faculty research and resulting opportunities and the development of resident research projects were integrated into the rotation. Twelve participating residents completed daily evaluations and took part in an exit focus group analyzed using a constant comparative method. Knowledge acquisition was assessed with a pre/post comprehensive examination instrument evaluated by a pairedt-test. Evaluations indicated generally high satisfaction throughout the rotation. Focus group analysis indicated that residents felt two important but competing goals existed: developing a research project and developing critical appraisal skills. The research knowledge of all participants improved significantly (mean/SD examination change +35.4%/+10.4%, range +20.0% to +53.6%,p< 0.001), and several new resident/faculty research collaborations arose from the rotation. A rotation of this nature is an efficient and effective means to increase research and critical appraisal knowledge and faculty/resident collaborations. As a result of our positive experience, the rotation will continue annually and has been expanded to include pediatric EM fellows. Longitudinal tracking of the participating trainee cohort will remain ongoing to assess the scholarly output impact of the rotation.

Primary biliary cholangitis (PBC) and primary sclerosing cholangitis (PSC) are immune-mediated biliary diseases that demonstrate prominent and restricted genetic association with human leukocyte antigen (HLA) alleles. In PBC, anti-mitochondrial antibodies (AMA) are specific and used as diagnostic biomarkers. PSC-relevant auto-antibodies remain controversial despite a distinct HLA association that mirrors archetypical auto-antigen driven disorders. Herein, we compared antibody-secreting B cells (ASCs) in PSC and PBC liver explants to determine if liver-infiltrating ASCs represent an opportune and novel source of disease-relevant auto-antibodies. Using enzymatic digestion and mechanical disruption, liver mononuclear cells (LIMCs) were isolated from fresh PSC and PBC explants and plasmablast (CD19+CD27+CD38hiCD138−) and plasma cell (CD19+CD27+CD38hiCD138+) ASCs were enumerated by flow cytometry. We observed 45-fold fewer plasma cells in PSC explants (n = 9) compared to PBC samples (n = 5, p

Background & Aims Recruitment of gut-derived memory T-cells to the liver is believed to drive hepatic inflammation in primary sclerosing cholangitis (PSC). However, whether gut-infiltrating and liver-infiltrating T-cells share T cell receptors (TCRs) and antigenic specificities is unknown. We used paired gut and liver samples from PSC patients with concurrent inflammatory bowel disease (PSC-IBD), and normal tissue samples from colon cancer controls, to assess potential T cell clonotype overlap between the two compartments. Methods High-throughput sequencing of TCRβ repertoires was applied on matched colon, liver and blood samples from patients with PSC-IBD (n=10), and on paired tumor-adjacent normal gut and liver tissue samples from colon cancer patients (n=10). Results An average of 9.7% (range: 4.7–19.9%) memory T cell clonotypes overlapped in paired PSC-IBD affected gut and liver samples, after excluding clonotypes present at similar frequencies in blood. Shared clonotypes constituted on average 16.0% (range: 8.7–32.6%) and 15.0% (range: 5.9–26.3%) of the liver and gut memory T-cells, respectively. A significantly higher overlap was observed between paired PSC-IBD affected samples (8.7%, p =0.0007) compared to paired normal gut and liver samples (3.6%), after downsampling to equal number of reads. Conclusion Memory T-cells of common clonal origin were detected in paired gut and liver samples of patients with PSC-IBD. Our data indicate that this is related to PSC-IBD pathogenesis, suggesting that memory T-cells driven by shared antigens are present in the gut and liver of PSC-IBD patients. Our findings support efforts to therapeutically target memory T cell recruitment in PSC-IBD. Lay summary Primary sclerosing cholangitis (PSC) is a devastating liver disease strongly associated with inflammatory bowel disease (IBD). The cause of PSC is unknown, but it has been suggested that the immune reactions in the gut and the liver are connected. Our data demonstrate for the first time that a proportion of the T-cells in the gut and the liver react to similar triggers, and that this proportion is particularly high in patients with PSC and IBD.

B cell activation and Ab production in response to protein Ags requires presentation of peptides for recruitment of T cell help. We and others have recently demonstrated that B cells can also acquire innate help by presenting lipid Ags via CD1d to NKT cells. Given the newfound contribution of NKT cells to humoral immunity, we sought to identify the pathways that regulate CD1 molecule expression in human B cells. We show that ex vivo, activated and memory B cells expressed lower levels of CD1d compared with resting, naive, and marginal zone-like B cells. In vitro, CD1d was downregulated by all forms of B cell activation, leaving a narrow temporal window in which B cells could activate NKT cells. CD1c expression and function also decreased following activation by CD40L alone, whereas activation via the BCR significantly upregulated CD1c, particularly on marginal zone-like B cells. We found that the CD40L-induced downreglation of CD1d and CD1c correlated with diminished expression of retinoic acid receptor α (RARα) response genes, an effect that was reversed by RARα agonists. However, BCR-induced upregulation of CD1c was independent of the RAR pathway. Our findings that both CD1d and CD1c are upregulated by RARα signaling in human B cells is distinct from effects reported in dendritic cells, in which CD1c is inversely downregulated. One functional consequence of CD1d upregulation by retinoic acid was NKT cell cytotoxicity toward B cells. These results are central to our understanding of how CD1-restricted T cells may control humoral immunity.

Natural killer T (NKT) cells are innate-like lymphocytes that recognize lipid antigens and have been shown to enhance B-cell activation and antibody production. B cells typically recruit T-cell help by presenting internalized antigens recognized by their surface antigen receptor. Here, we demonstrate a highly efficient means whereby human B cells present lipid antigens to NKT cells, capturing the antigen using apolipoprotein E (apoE) and the low-density lipoprotein receptor (LDL-R). ApoE dramatically enhances B-cell presentation of alpha-galactosylceramide (αGalCer), an exogenous CD1d presented antigen, inducing activation of NKT cells and the subsequent activation of B cells. B cells express the LDL-R on activation, and the activation of NKT cells by B cells is completely LDL-R dependent, as shown by blocking experiments and the complete lack of presentation when using apoE2, an isoform of apoE incapable of LDL-R binding. The dependence on apoE and the LDL-R is much more pronounced in B cells than we had previously seen in dendritic cells, which can apparently use alternate pathways of lipid antigen uptake. Thus, B cells use an apolipoprotein-mediated pathway of lipid antigen presentation, which constitutes a form of innate help for B cells by NKT cells.

X-linked lympho-proliferative (XLP) is an immunodeficiency condition caused by mutation or deletion of the gene encoding the adaptor protein SAP/SH2D1A. Besides defects in T cell and NK cell function and an absence of NKT cells, XLP can also manifest as lymphomas resulting primarily from uncontrolled B cell proliferation upon acute infection by Epstein-Barr virus. While it has been demonstrated that SAP regulates the functions of T cells and NK cells through the SLAM family of immunoreceptors, its role in B cells has not been defined. Here we show that SAP forms a ternary complex with the kinase Lyn and the inhibitory IgG Fc receptor FcgammaRIIB to regulate B cell proliferation and survival. SAP binds directly and simultaneously to the Lyn SH3 domain and an Immuno-receptor Tyrosine-based Inhibitory Motif (ITIM) in FcgammaRIIB, resulting in the activation of the latter. Moreover, SAP associates with FcgammaRIIB in mouse splenic B cells and promotes its tyrosine phosphorylation. Expression of SAP in the A20 B cell line led to a marked reduction in Blnk phosphorylation, a decrease in Akt activation, and a near-complete ablation of phosphorylation of the MAP kinases Erk1/2, p38 and JNK upon colligation of FcgammaRIIB with the B cell receptor (BCR). In contrast, an XLP-causing SAP mutant was much less efficient in eliciting these effects in B cells. Furthermore, compared to A20 cells, SAP transfectants displayed a significantly reduced rate of proliferation and an increased sensitivity to activation-induced cell death. Collectively these data identify an intrinsic function for SAP in inhibitory signaling in B cells and suggests that SAP may play an important role in balancing positive versus negative immune responses.

ObjectivesEmergency physicians who work in academic settings enjoy an expanding number of roles beyond that of the skilled clinician. Faculty development (FD) encompasses the broad range of activities that institutions use to renew skill-sets and assist faculty members in these multiple roles. This study seeks to define the current FD needs and interests of Canadian academic emergency physicians (AEPs).MethodsAn online survey was administered to 943 AEPs in eight centers across Canada to determine their current FD activities, provide a detailed understanding of their FD needs and interests, elucidate the perceived barriers to and motivation for engaging in FD, and identify preferred methods of delivery for FD activities.ResultsThis national, cross-sectional survey was completed by 336 respondents. It shows that need for FD is universally high, particularly in traditional domains of scholarship, leadership and education (79%, 80%, 87% overall interest, respectively). However, the study also suggests that there is increasing need for FD in areas where current participation is lowest, namely research and social accountability (12% and 13% more interest, respectively). Senior and junior faculty evince equivalent overall FD interest (p>0.05), whereas female AEPs expressed greater overall FD needs in leadership (1.82 vs 1.44 activities, p=0.003) than males. Continued participation in FD activities is best promoted by offering relevant topics, at convenient times and locations.ConclusionsThis study reports the first comprehensive national FD needs assessment of Canadian academic emergency physicians.

Invariant natural killer T (iNKT) cells are a highly conserved subset of unconventional T lymphocytes that express a canonical, semi-invariant T cell receptor (TCR) and surface markers shared with the natural killer cell lineage. iNKT cells recognize exogenous and endogenous glycolipid antigens restricted by non-polymorphic CD1d molecules, and are highly responsive to the prototypical agonist, α-galactosylceramide. Upon activation, iNKT cells rapidly coordinate signaling between innate and adaptive immune cells through the secretion of proinflammatory cytokines, leading to the maturation of antigen-presenting cells and expansion of antigen-specific CD4+ and CD8+ T cells. Because of their potent immunoregulatory properties, iNKT cells have been extensively studied and are known to play a pivotal role in mediating immune responses against microbial pathogens including viruses. Here, we review evidence that herpesviruses manipulate CD1d expression to escape iNKT cell surveillance and establish lifelong latency in humans. Collectively, published findings suggest that iNKT cells play critical roles in anti-herpesvirus immune responses and could be harnessed therapeutically to limit viral infection and viral-associated disease.

X-linked lymphoproliferative disease (XLP) is a fatal immunological disorder that typically manifests following EBV infection. XLP patients exhibit a number of immune defects including abnormal T, B, and NK lymphocyte function. These defects have been attributed to mutations of Src homology 2 domain-containing gene 1A (SH2D1A), the gene encoding signaling lymphocytic activation molecule-associated protein (SAP), an intracellular adaptor molecule expressed in lymphocytes. We have observed that SAP knockout (SAPKO) mice and humans with XLP have a complete lack of CD1d-restricted NKT cells. As expected, SAPKO mice injected with the NKT cell agonist, α-galactosylceramide failed to generate NKT cell IFN-γ or IL-4. Furthermore, in contrast to wild-type littermates, SAPKO mice coinjected with OVA and α-galactosylceramide failed to mount OVA-specific CTL responses. These data suggest that an absence of NKT cells may underlie part of the immune dysregulation seen in SAPKO mice and in XLP patients.

Intracranial berry aneurysms (IA) can develop in arterial walls where the endothelial layer has weakened. Subarachnoid haemorrhage (SAH) occurs when an IA bursts causing blood to flow into the brain space. SAH leads to death in 35–50% of patients, and to brain damage in 25–50% of survivors. Familial IA (FIA) is suspected when a patient has two or more first-degree relatives with IA or SAH. The risk for a ruptured aneurysm in an individual with FIA is 17 times greater compared to the general population. Currently, there is no genetic test to assess the risk of developing an IA, and repeated brain imaging tests are required to screen those at risk as affected individuals are often asymptomatic. We have identified a family with a history of FIA spanning over three-generations, with three affected and four unaffected siblings. The inheritance pattern of FIA in this family appears to be autosomal dominant, strongly suggestive of a true Mendelian disorder. Our hypothesis is that there will be a single rare pathogenic variant that leads to the development of FIA in this family. We have collected DNA samples from this family, and carried out whole-genome SNP microarray on DNA from one affected and four unaffected siblings. We also performed whole-exome sequencing (WES) on one of the affected siblings. We will further filter our list of candidate genes created from genomic areas of interest that were identified from the microarray data using our list of rare, predicted damaging, variants generated from the WES data. These areas of interest will include regions shared between affected individuals, and exclude those shared with unaffected individuals. This family is unique to our knowledge, and our research could lead to the first identification of a monogenic cause for IA.

SHORT syndrome is a rare, multisystem disease characterized by short stature, anterior-chamber eye anomalies, characteristic facial features, lipodystrophy, hernias, hyperextensibility, and delayed dentition. As part of the FORGE (Finding of Rare Disease Genes) Canada Consortium, we studied individuals with clinical features of SHORT syndrome to identify the genetic etiology of this rare disease. Whole-exome sequencing in a family trio of an affected child and unaffected parents identified a de novo frameshift insertion, c.1906_1907insC (p.Asn636Thrfs∗18), in exon 14 of PIK3R1. Heterozygous mutations in exon 14 of PIK3R1 were subsequently identified by Sanger sequencing in three additional affected individuals and two affected family members. One of these mutations, c.1945C>T (p.Arg649Trp), was confirmed to be a de novo mutation in one affected individual and was also identified and shown to segregate with the phenotype in an unrelated family. The other mutation, a de novo truncating mutation (c.1971T>G [p.Tyr657∗]), was identified in another affected individual. PIK3R1 is involved in the phosphatidylinositol 3 kinase (PI3K) signaling cascade and, as such, plays an important role in cell growth, proliferation, and survival. Functional studies on lymphoblastoid cells with the PIK3R1 c.1906_1907insC mutation showed decreased phosphorylation of the downstream S6 target of the PI3K-AKT-mTOR pathway. Our findings show that PIK3R1 mutations are the major cause of SHORT syndrome and suggest that the molecular mechanism of disease might involve downregulation of the PI3K-AKT-mTOR pathway.

Epstein-Barr virus (EBV) infection results in rapid loss of CD1d expression from the surface of infected B cells, thus enabling the virus to evade immune recognition by natural killer T (NKT) cells. Using pharmacologic means to boost CD1d expression, potent NKT cell effector functions can be elicited toward EBV-infected B cells, suggesting the promise of novel strategies to target EBV-associated diseases such as some B-cell malignancies.