The Age Specific Microbiome of Children with Milk, Egg, and Peanut Allergy

BACKGROUND

Immune regulation by gut microbiota is affected by dysbiosis and may precede food allergy onset. Prior studies lack comparisons stratified by age and clinical phenotype.

OBJECTIVE

The primary objective was to assess the microbiome of children with food allergy (< 3years, 3-18years) compared to similar aged children without food allergy.

METHODS

A real-world prospective cross-sectional study performed from 2014-2019 recruited children highly likely to have milk, egg or peanut allergy defined by history and serum IgE or confirmed by food challenge. 16S ribosomal RNA sequencing identified stool microbial DNA. Alpha- and beta-diversity was compared between food-allergic groups and healthy controls stratified by age. Differential abundance for non-a-priori taxa was accepted at absolute fold-change > 2 and q-value < 0.05.

RESULTS

70 patients were included(56 food-allergic;14 healthy controls). Groups were not significantly different in age, gender at birth, race, mode of delivery, breastfeeding duration, or antibiotic exposure. Younger food-allergic children had similar alpha-diversity compared to controls. Beta diversity was significantly different by age(p=0.001). There was differential abundance of several a-priori(p<0.05) taxa (including Clostridia) only in younger children. Both a-priori (including Coprococcus, Clostridia) and non-a-priori(q<0.05) Acidobacteria_Gp15,Aestuariispira, Tindallia and Desulfitispora were significant in older food-allergic children, especially with peanut allergy.

CONCLUSION

Dysbiosis associates with food allergy, most prominent in peanut-allergic older children. Younger children with and without food allergy have fewer differences in gut microbiota. This correlates with clinical observations of persistence of peanut allergy, and improved efficacy and safety of oral immunotherapy in younger children. Age under 3 should be considered when initiating therapeutic interventions.

Genetic variations in NLRP3 and NLRP12 genes in adult-onset patients with autoinflammatory diseases: a comparative study

Objectives

Cryopyrin-associated periodic syndrome or NLRP3-associated autoinflammatory disease (NLRP3-AID) and NLRP12-AID are both Mendelian disorders with autosomal dominant inheritance. Both diseases are rare, primarily reported in the pediatric population, and are thought to be phenotypically indistinguishable. We provide the largest cohort of adult-onset patients and compared these diseases and the gene variant frequency to population controls.

Methods

A cohort of adult patients with AIDs were retrospectively studied. All underwent molecular testing for periodic fever syndrome gene panels after extensive and negative workups for systemic autoimmune and other related diseases. Patients were divided into Group 1- NLRP3-AID patients with NLRP3 variants (N=15), Group 2- NLRP12-AID with NLRP12 variants (N=14) and Group 3- both NLRP3 and NLRP12 (N=9) variants. Exome sequence data of two large control populations including the ARIC study were used to compare gene variant distribution and frequency.

Results

All 38 patients were Caucasian with women accounting for 82%. Median age at diagnosis was 41 ± 23 years and the disease duration at diagnosis was 14 ± 13 years. We identified statistically significant differences between the groups, notably that gastrointestinal symptoms as well as evaluations for same were significantly more frequent in patients with NLRP12 variants, and headaches/dizziness were less common among the NLRP12 patients. Livedo reticularis was noted in four patients, exclusively among NLRP12 carriers. Over 50% of patients in Groups 1 and 2 carry low-frequency disease-associated variants, while the remaining carry rare variants. We unprecedently identified digenic variants, i.e., the coexistence of NLRP3 and NLRP12, which were either both low frequency or low frequency/rare. Allele frequencies of all variants identified in our cohort were either absent or significantly lower in the control populations, further strengthening the evidence of susceptibility of these variants to SAID phenotypes.

Conclusion

Our comparative study shows that both NLRP3-AID and NLRP12-AID share similar clinical phenotypes, yet there are significant differences between them with regard to gastrointestinal and neurological symptoms. A spectrum of high to low genetic variations in both genes can contribute to SAID individually or in combination.

Implications of combined NOD2 and other gene mutations in autoinflammatory diseases

NOD-like receptors (NLRs) are intracellular sensors associated with systemic autoinflammatory diseases (SAIDs). We investigated the largest monocentric cohort of patients with adult-onset SAIDs for coinheritance of low frequency and rare mutations in NOD2 and other autoinflammatory genes. Sixty-three patients underwent molecular testing for SAID gene panels after extensive clinical workups. Whole exome sequencing data from the large Atherosclerosis Risk in Communities (ARIC) study of individuals of European-American ancestry were used as control. Of 63 patients, 44 (69.8%) were found to carry combined gene variants in NOD2 and another gene (Group 1), and 19 (30.2%) were carriers only for NOD2 variants (Group 2). The genetic variant combinations in SAID patients were digenic in 66% (NOD2/MEFV, NOD2/NLRP12, NOD2/NLRP3, and NOD2/TNFRSF1A) and oligogenic in 34% of cases. These variant combinations were either absent or significantly less frequent in the control population. By phenotype-genotype correlation, approximately 40% of patients met diagnostic criteria for a specific SAID, and 60% had mixed diagnoses. There were no statistically significant differences in clinical manifestations between the two patient groups except for chest pain. Due to overlapping phenotypes and mixed genotypes, we have suggested a new term, "Mixed NLR-associated Autoinflammatory Disease ", to describe this disease scenario. Gene variant combinations are significant in patients with SAIDs primarily presenting with mixed clinical phenotypes. Our data support the proposition that immunological disease expression is modified by genetic background and environmental exposure. We provide a preliminary framework in diagnosis, management, and interpretation of the clinical scenario.

Inpatient Rheumatology Consultation Prompted by Positive Autoantibodies in Patients Receiving Intravenous Immunoglobulin Therapy: A Case Series and Literature Review

Intravenous immunoglobulin (IVIG) is a therapeutic preparation used in the treatment of multiple diseases. Autoimmune testing with antinuclear antibody (ANA) screening is often obtained for some of these conditions, but only after initiation of IVIG treatment. This can present a diagnostic dilemma in hospitalized patients and may trigger a rheumatology consultation. We describe our consultative inpatient two-year experience with five such patients and review the pertinent literature. A retrospective chart review of rheumatology inpatient consultations between 6-2018 and 6-2020 at our academic tertiary care hospital for post-IVIG positive serologies was performed. A pertinent literature review was performed. Five patients had a positive ANA and other autoantibodies detected in their serum after they received IVIG for non-rheumatological conditions. None of these patients met the criteria for a connective tissue disease. The literature review identified a total of 58 patients from case reports and case series, several of whom tested positive for ANA and other antibodies after receiving IVIG. Studies assessing specific IVIG products detected multiple autoantibodies in the donor pool. Autoimmune testing is initiated on inpatients receiving IVIG for non-rheumatological conditions. If an autoantibody ANA screen is positive, a rheumatology consultation may be requested. In the absence of pre-IVIG antibody tests it is difficult to interpret post-IVIG-positive antibodies. Whether such positive antibodies are of clinicopathological significance is determined by clinical judgment and time.

Macroglobulinemia and Autoinflammatory Disease

Macroglobulinemia is associated with Schnitzler syndrome (SchS) and Waldenstrom macroglobulinemia (WM). The aim of this article was to review the above-mentioned two diseases from clinical aspects and their potential genetic links. We performed a PubMed search using the following keywords: "SchS," "WM," "autoinflammatory disease," "periodic fever syndrome," and "nucleotide-binding oligomerization domain containing protein 2 (NOD2)." A case is exemplified. Both SchS and WM share some clinical phenotypes, and SchS can evolve into WM. Though no genetic link to SchS has been established, myeloid differentiation primary response gene 88 (MyD88) mutations are detected in one-third of SchS patients and 86% WM patients. Genetic analysis of periodic fever syndrome genes has detected NOD2 mutations in 18% SchS patients and rarely NLRP3 mutations. The literature data suggest that both MyD88 and NOD2 mutations may contribute to SchS. Both MyD88 and NOD2 are known to play important roles in innate immune response, and they may be cooperative in certain autoinflammatory diseases. Molecular analysis of NOD2 mutations may be incorporated into genetic testing for patients with suspected SchS or SchS/WM.

Effective use of monoclonal antibodies for treatment of persistent COVID-19 infection in a patient on rituximab

As we are over a year into the COVID-19 pandemic, we have made many forward strides in therapeutics. These treatments, such as monoclonal antibodies, have help mitigate the detrimental and often fatal consequences of COVID-19. The current indication for the use of monoclonal antibodies is mild to moderate COVID-19 infection within 10 days of symptom onset in those who are at high risk of progression to severe disease. However, their role in patients with prolonged symptoms is not clear. We present a unique case of monoclonal antibodies use after 54 days of symptom onset in an immunosuppressed patient with persistent COVID-19 infection despite standard treatment. This case illustrates the potential use of monoclonal antibodies outside of the current recommended therapeutic window in immunosuppressed patients, who may have difficulty with viral clearance.

The Role of Obesity in the Immunopathogenesis of COVID-19 Respiratory Disease and Critical Illness

Coronavirus disease (COVID-19), the clinical syndrome caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), is currently a global health pandemic with substantial morbidity and mortality. COVID-19 has cast a shadow on nearly every aspect of society, straining health systems and economies across the world. Although it is widely accepted that a close relationship exists between obesity, cardiovascular disease, and metabolic disorders on infection, we are only beginning to understand ways in which the immunological sequelae of obesity functions as a predisposing factor related to poor clinical outcomes in COVID-19. As both the innate and adaptive immune systems are each primed by obesity, the alteration of key pathways results in both an immunosuppressed and hyperinflammatory state. The present review will discuss the cellular and molecular immunology of obesity in the context of its role as a risk factor for severe COVID-19, discuss the role of cytokine storm, and draw parallels to prior viral epidemics such as severe acute respiratory syndrome (SARS), Middle East respiratory syndrome (MERS), and 2009 H1N1.

Yao Syndrome: A Potential Role and Association of Vasoactive Intestinal Peptide with NOD2

Nucleotide-binding oligomerization domain containing protein 2 (NOD2) is a cytosolic receptor. Both NOD2 and vasoactive intestinal peptide (VIP) are critical in regulation of immune and inflammatory response. Yao syndrome (YAOS, OMIM 617321) is an autoinflammatory disease associated with specified NOD2 mutations. Herein, we report a well-studied case of YAOS masquerading as mast cell disorder and neuroendocrine tumors to support the involvement of VIP in YAOS. For the first time, this case study suggests a potential relationship between NOD2 and VIP. This could provide a novel avenue for mechanistic study of NOD2-associated disease.