NFκB pathway dysregulation due to reduced RelB expression leads to severe autoimmune disorders and declining immunity.

BACKGROUND: Genetic aberrations in the NFκB pathway lead to primary immunodeficiencies with various degrees of severity. We previously demonstrated that complete ablation of the RelB transcription factor, a key component of the alternative pathway, results in an early manifested combined immunodeficiency requiring stem cell transplantation. OBJECTIVE: To study the molecular basis of a progressive severe autoimmunity and immunodeficiency in three patients. METHODS: Whole exome sequencing was performed to identify the genetic defect. Molecular and cellular techniques were utilized to assess the variant impact on NFκB signaling, canonical and alternative pathway crosstalk, as well as the resultant effects on immune function. RESULTS: Patients presented with multiple autoimmune progressive severe manifestations encompassing the liver, gut, lung, and skin, becoming debilitating in the second decade of life. This was accompanied by a deterioration of the immune system, demonstrating an age-related decline in naïve T cells and responses to mitogens, accompanied by a gradual loss of all circulating CD19+ cells. Whole exome sequencing identified a novel homozygous c. C1091T (P364L) transition in RELB. The P364L RelB protein was unstable, with extremely low expression, but retained some function and could be transiently and partially upregulated following Toll-like receptor stimulation. Stimulation of P364L patient fibroblasts resulted in a marked rise in a cluster of pro-inflammatory hyper-expressed transcripts consistent with the removal of RelB inhibitory effect on RelA function. This is likely the main driver of autoimmune manifestations in these patients. CONCLUSION: Incomplete loss of RelB provided a unique opportunity to gain insights into NFκB's pathway interactions as well as the pathogenesis of autoimmunity. The P364L RelB mutation leads to gradual decline in immune function with progression of severe debilitating autoimmunity.

Higher Rates of Hospitalizations among Pediatric Refugees than Local Population Attending the Emergency Department and Longer In-patient Stay.

BACKGROUND: The global refugee crises have raised concerns among medical communities worldwide; nonetheless, access to healthcare has rarely been studied even though refugees are a medically high-risk group. OBJECTIVES: To compare pediatric department admission rates from the pediatric emergency department (PED) of refugees and Israelis. METHODS: We compared data from refugee and Israeli children admitted to the pediatric department at Wolfson Medical Center in Israel between 2013-2017. RESULTS: A total of 104,244 patients (aged 0-18 years) came to the PED. Admission rate to the pediatric department for refugees was 695/2541 (27%) compared to 11,858/101,703 (11.7%) Israeli patients (P < 0.001). Hospital stay for patients 0-2-years of age was 3.22 ± 4.80 days for refugees vs. 2.78 ± 3.17 for Israelis (P < 0.03). Re-admission rate within 7 days was 1.3% for refugees and 2.6% for Israelis (P < 0.05). Dermatological diseases (e.g., impetigo and cellulitis) were more frequent in refugees (23.30% vs. 13.15%, P < 0.01); however, acute gastroenteritis and respiratory diagnoses were more common in Israelis (18.52% vs. 11.72%, P < 0.05 and 14.84% vs. 6.26%, P < 0.01, respectively). Neurological diseases (e.g., febrile convulsions) were also more frequent in Israelis (7.7% vs. 3%, P < 0.05). Very significantly, 23% of refugees had no healthcare coverage, while only 0.2% of the Israelis had none (P < 0.001). CONCLUSIONS: We found significant morbidity in refugees compared to the local Israeli pediatric population, highlighting the need for different approaches for each population.

Homozygous GLUL deletion is embryonically viable and leads to glutamine synthetase deficiency.

Glutamine synthetase (GS) is the enzyme responsible for the biosynthesis of glutamine, providing the only source of endogenous glutamine necessary for several critical metabolic and developmental pathways. GS deficiency, caused by pathogenic variants in the glutamate-ammonia ligase (GLUL) gene, is a rare autosomal recessive inborn error of metabolism characterized by systemic glutamine deficiency, persistent moderate hyperammonemia, and clinically devastating seizures and multi-organ failure shortly after birth. The four cases reported thus far were caused by homozygous GLUL missense variants. We report a case of GS deficiency caused by homozygous GLUL gene deletion, diagnosed prenatally and likely representing the most severe end of the spectrum. We expand the known phenotype of this rare condition with novel dysmorphic, radiographic and neuropathologic features identified on post-mortem examination. The biallelic deletion identified in this case also included the RNASEL gene and was associated with immune dysfunction in the fetus. This case demonstrates that total absence of the GLUL gene in humans is viable beyond the embryonic period, despite the early embryonic lethality found in GLUL animal models.

Combined immunodeficiency and atopy caused by a dominant negative mutation in caspase activation and recruitment domain family member 11 (CARD11).

BACKGROUND: Combined immunodeficiency (CID) is a T-cell defect frequently presenting with recurrent infections, as well as associated immune dysregulation manifesting as autoimmunity or allergic inflammation. OBJECTIVE: We sought to identify the genetic aberration in 4 related patients with CID, early-onset asthma, eczema, and food allergies, as well as autoimmunity. METHODS: We performed whole-exome sequencing, followed by Sanger confirmation, assessment of the genetic variant effect on cell signaling, and evaluation of the resultant immune function. RESULTS: A heterozygous novel c.C88T 1-bp substitution resulting in amino acid change R30W in caspase activation and recruitment domain family member 11 (CARD11) was identified by using whole-exome sequencing and segregated perfectly to family members with severe atopy only but was not found in healthy subjects. We demonstrate that the R30W mutation results in loss of function while also exerting a dominant negative effect on wild-type CARD11. The CARD11 defect altered the classical nuclear factor κB pathway, resulting in poor in vitro T-cell responses to mitogens and antigens caused by reduced secretion of IFN-γ and IL-2. CONCLUSION: Unlike patients with biallelic mutations in CARD11 causing severe CID, the R30W defect results in a less profound yet prominent susceptibility to infections, as well as multiorgan atopy and autoimmunity.

Hematopoietic stem cell transplantation in patients with gain-of-function signal transducer and activator of transcription 1 mutations.

BACKGROUND: Gain-of-function (GOF) mutations in signal transducer and activator of transcription 1 (STAT1) cause susceptibility to a range of infections, autoimmunity, immune dysregulation, and combined immunodeficiency. Disease manifestations can be mild or severe and life-threatening. Hematopoietic stem cell transplantation (HSCT) has been used in some patients with more severe symptoms to treat and cure the disorder. However, the outcome of HSCT for this disorder is not well established. OBJECTIVE: We sought to aggregate the worldwide experience of HSCT in patients with GOF-STAT1 mutations and to assess outcomes, including donor engraftment, overall survival, graft-versus-host disease, and transplant-related complications. METHODS: Data were collected from an international cohort of 15 patients with GOF-STAT1 mutations who had undergone HSCT using a variety of conditioning regimens and donor sources. Retrospective data collection allowed the outcome of transplantation to be assessed. In vitro functional testing was performed to confirm that each of the identified STAT1 variants was in fact a GOF mutation. RESULTS: Primary donor engraftment in this cohort of 15 patients with GOF-STAT1 mutations was 74%, and overall survival was only 40%. Secondary graft failure was common (50%), and posttransplantation event-free survival was poor (10% by 100 days). A subset of patients had hemophagocytic lymphohistiocytosis before transplant, contributing to their poor outcomes. CONCLUSION: Our data indicate that HSCT for patients with GOF-STAT1 mutations is curative but has significant risk of secondary graft failure and death.

Risk Factors and Characteristics of Candidemia After Cardiac Surgery in Pediatric Patients in Central Israel.

BACKGROUND: Candidemia is a serious complication in pediatric patients with congenital heart defects (CHD) after cardiac surgery. Information about the epidemiology, clinical characteristics and risk factors for candidemia in this vulnerable population remains limited. METHODS: This retrospective case-control study was conducted in 2 pediatric intensive care units between 2004 and 2019. All patients <18 years old who developed candidemia following cardiac surgery were included. Each case was matched with 2 control patients based on age and date of surgery. Multivariable logistic regression analysis was conducted to determine the risk factors for postoperative candidemia. RESULTS: Thirty-five candidemia cases were identified and matched to 70 control cases. The incidence of candidemia was 6.3 episodes per 1000 admissions. The median age for candidemia cases was 4 months. The attributable mortality was 28.5%. The predominant (54%) pathogens isolated were non- albicans Candida species, of which C. parapsilosis isolates demonstrated high resistance to fluconazole (70%). Independent risk factors associated with candidemia included cumulative antibiotic exposure for ≥4 days [OR: -4.3; 95% confidence interval (CI): 1.3-14.6; P = 0.02], the need for total parenteral nutrition or peritoneal dialysis (OR: -6.1; 95% CI: 2-18.8; P = 0.001), male sex (OR: 6.2; 95% CI: 1.9-20.3; P = 0.002) and delayed sternal closure≥2 days (OR: -3.2; 95% CI: 1-11.2; P = 0.05). CONCLUSIONS: Postoperative candidemia in children with CHD is an uncommon but severe complication. Our study revealed an unexpectedly high frequency of fluconazole-resistant C. parapsilosis as the main cause of non- albicans candidemia. In addition to confirming previously recognized risk factors, our results reveal new potential risk factors such as delayed sternal closure and male sex.

Unintentional Acute Poisoning Related Emergency Department Visits in Children in a Single-Center: A Nine-Year Prospective Survey.

Pediatric morbidity due to unintentional poison exposure is a significant burden on public health. We prospectively characterize patterns of unintentional poison exposure in a single pediatric emergency department, using a detailed computerized questionnaire for all unintentional injuries admitted during 2009 to 2017. Out of 71,765 visits due to unintentional injuries, 252 children were admitted due to unintentional poison exposure. Most (198/252, 79%) were between 1 and 3 years of age. The majority of events (209/252, 82.9%) occurred at the patient's home and 81% (205/255) were classified as exploratory ingestion. In 41/252 (14%) cases, exposure to more than one substance was reported. Most events 231/293 (79%) involved medications and 21% were due to domestic products. Four medications account for 45% of the events (Paracetamol, Salbutamol, Antihypertensive, and Antidepressants). Opioids were responsible for only 1.7%. By, collaboration between government, public health, educational institutions and commercial companies, can the burden of pediatric unintentional poison exposure be reduced.

Safety and Tolerability of Mebendazole in Infants Under 1 Year of Age.

This paper presents the largest cohort to date of infants under 1 year of age treated with mebendazole. We evaluated the occurrence of mebendazole-associated clinical and laboratory toxicity as safety data in this age group are currently lacking.

Kawasaki disease with a concomitant primary Epstein - Barr virus infection.

BACKGROUND: Kwasaki disease (KD) is the leading cause of acquired heart disease in children in most developed countries. The cause of KD remains unknown. The presumed theory is that KD occurs due to one or more infectious agents who evoke an abnormal immunological response in susceptible individuals. Epstein - Barr virus (EBV) infection has been considered as a suspected causative agent because of the potential effect on the immune system. CASE PRESENTATION: A previously healthy 19 month old boy presented with a 6 day history of fever accompanied by a diffuse macular erythematous rash that appeared 1 day after. The physical examination on admission revealed bilateral non-suppurative conjunctivitis, dry fissured and injected lips without "strawberry" tongue, diffuse macular rash on the trunk, face and limbs, swelling of the hands and feet, and right cervical lymphadenopathy (2 cm in diameter). Following fulfillment of all the clinical criteria, the diagnosis of KD was made and treatment with IVIG 2 g/Kg was administered along with oral aspirin (80 mg/ kg/day). However, despite the treatment, he remained febrile for an additional 2 days with persistent clinical manifestations. Therefore, he received a second 2 g/kg IVIG course with a favorable response. On the 14th day of illness the patient became febrile again and was readmitted. Blood examinations revealed remarkable leukocytosis up to 35.7 X 109/L with 87.3% lymphocytes and the blood smear revealed atypical lymphocytes and monocytes. The liver enzymes were elevated. The serology for infectious mononucleosis from his first admission revealed: IgM CMV (+), IgG CMV (-); IgM VCA EBV (+) IgG VCA EBV (-), IgG EBNA (-). To confirm infectious mononucleosis following the administration of 2 doses of IVIG, serum EBV PCR was performed and was positive (1.6X 103 cp/ml). CONCLUSIONS: We describe here a case of KD with a concomitant primary EBV infection. To the best of our knowledge, this is the first case in western country that describes KD with acute EBV infection as confirmed by PCR. The case we described stands as a contribution in favor of the possible role of EBV in the development of KD.

Minor Clinical Impact of COVID-19 Pandemic on Patients With Primary Immunodeficiency in Israel.

In the last few months the world has witnessed a global pandemic due to severe acute respiratory syndrome-coronavirus-2 (SARS-CoV-2) infection causing coronavirus disease 2019 (COVID-19). Obviously, this pandemic affected individuals differently, with a significant impact on populations considered to be at high-risk. One such population, was assumed to be patients with primary genetic defect involving components or pathways of the immune system. While human immunity against COVID-19 is not fully understood, it is, so far, well documented, that both adaptive and innate cells have a critical role in protection against SARS-CoV-2. Here, we aimed to summarize the clinical and laboratory data on primary immunodeficiency (PID) patients in Israel, who were tested positive for SARS-CoV-2, in order to estimate the impact of COVID-19 on such patients. Data was collected from mid-February to end-September. During this time Israel experienced two "waves" of COVID-19 diseases; the first, from mid-February to mid-May and the second from mid-June and still ongoing at the end of data collection. A total of 20 PID patients, aged 4 months to 60 years, were tested positive for SARS-CoV-2, all but one, were detected during the second wave. Fourteen of the patients were on routine monthly IVIG replacement therapy at the time of virus detection. None of the patients displayed severe illness and none required hospitalization; moreover, 7/20 patients were completely asymptomatic. Possible explanations for the minimal clinical impact of COVID-19 pandemic observed in our PID patients include high level of awareness, extra-precautions, and even self-isolation. It is also possible that only specific immune pathways (e.g. type I interferon signaling), may increase the risk for a more severe course of disease and these are not affected in many of the PID patients. In some cases, lack of an immune response actually may be a protective measure against the development of COVID-19 sequelae.

Two different STAT1 gain-of-function mutations lead to diverse IFN-γ-mediated gene expression.

Signal transducer and activator of transcription 1 (STAT1) regulates multiple biological processes downstream of a variety of cytokine receptors in many cell types. Heterozygous gain-of-function (GOF) mutations in STAT1 have been associated with a diverse phenotype encompassing chronic mucocutaneous candidiasis (CMCC) and declining immunity. There is no clear correlation between STAT1 domain-specific mutations and phenotype, and it remains unclear why GOF mutations in STAT1 result in such a wide spectrum of clinical presentations. To begin exploring this dilemma, we have studied the patterns of gene expression mediated by two different GOF mutations. Analysis of IFN-γ response elements using RNA microarrays in cells transfected with the rare H629Y mutant or the common R274G mutant showed distinct patterns of gene expression. We show here that the impact of GOF mutations in STAT1 is variant-specific. This difference in gene expression may explain the diversity in clinical manifestations experienced by these patients.

A homozygous mutation in the stem II domain of RNU4ATAC causes typical Roifman syndrome.

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.

Risk Factors for Sporadic Infection With Campylobacter Spp. Among Children in Israel: A Case-control Study.

BACKGROUND: Campylobacter spp. has been identified as one of the leading causes of bacterial gastroenteritis in the world. In recent years, an increase in the incidence of campylobacteriosis in several countries, including Israel, was demonstrated. The incidence rate of campylobacteriosis in Israel increased from 22.3 per 100,000 in 1997 to 77.4 per 100,000 in 2009. The aim of this study was to explore risk factors for sporadic infection with Campylobacter among young children in Israel. METHODS: A matched case-control study was performed to investigate risk factors for sporadic Campylobacter infection among 113 affected children of 1-5 years of age and 113 age-matched, gender-matched and neighborhood-matched controls. Information about exposure to potential risk factors was obtained via telephone interview and was evaluated by conditional logistic regression analysis. RESULTS: In the multivariable model, for each additional chicken meal consumed during the week before the onset of illness, the odds for Campylobacter infection increased by 32% [adjusted matched odds ratios (aMOR): 1.32; 95% confidence interval (CI): 1.01-1.72; P = 0.04], whereas consumption of fruits and vegetables decreased the odds for Campylobacter infection by 97% (aMOR: 0.03; 95% CI: 0.00-0.28; P < 0.01), and for each additional child living in the household, the odds for infection decreased by 48% (aMOR: 0.52; 95% CI: 0.33-0.83; P < 0.01). Using diaper increased the odds for campylobacteriosis (aMOR: 7.36; 95% CI: 1.66-32.70; P < 0.01). CONCLUSIONS: Interventions that focus on proper handling of chicken and chicken products, hand washing and encouraging consumption of fruits and vegetables could help in controlling Campylobacter infections.

Eosinophilic esophagitis: an immune-mediated esophageal disease.

Eosinophilic esophagitis (EoE) is an emerging disease defined by esophageal dysfunction, by typical endoscopic findings and by abnormal eosinophilic inflammation within the esophagus. Eosinophilic accumulation in the esophagus occurs as a result of esophageal overexpression of pro-inflammatory mediators, including T cells and mast cells, cytokines such as interleukin (IL)-13, IL-5 and IL-15, as well as chemoattractants (eotaxin and transforming growth factor-ß1, fibroblast growth factor and the newly characterized gene--thymic stromal lymphopoietin, which is a key regulator of allergic sensitization initiation). The role of allergy, particularly food allergy in EoE is indisputable, as elimination diet is a proven commonly used treatment for the disease. However, unlike classical immediate IgE-mediated reaction to allergen, EoE is associated with an altered immune response, characterized by a combination of IgE-mediated and non-IgE-mediated mechanisms. In this review, we aim to discuss the many typical aspects of EoE as opposed to other entities involving the esophagus, with focusing on the aberrant immune-mediated key players contributing to the pathogenesis of this unique disease.