Allergy and Immunology

Research Highlights

Recognized Excellence of Division Trainees and Faculty

The Division of Allergy and Immunology is proud of the excellence of its undergraduate, graduate, postdoctoral and clinical trainees and junior investigators. Recognition of several for their achievements throughout the year, include:

• Netali Morgenstern Ben Baruch, a binational scholar in the Rothenberg Lab, is a recipient of a Zuckerman Israeli Postdoctoral Scholarship.
• Hayley Flanagan, summer student in the Rothenberg Lab, won first place in the Infectious Disease and Immunology category at the 59th Annual National Student Research Forum (NSRF) for her summer research at Cincinnati Children's.

Eosinophil-Depleting Drug Now Being Studied for Eosinophilic Gastritis

Divisional investigators, under the leadership of Marc Rothenberg, MD, PhD, developed an investigator-initiated study aiming to examine the effect of the eosinophil-depleting drug benralizumab on patients with eosinophilic gastritis (EG), an allergic disease involving severe inflammation of the stomach. At present, there are no FDA-approved medicines for this disease. Benralizumab is a humanized monoclonal antibody directed against the alpha subunit of the interleukin 5 receptor (IL-5Rα). The binding of the antibody to IL-5Rα results in eosinophil depletion via antibody-dependent cellular cytotoxicity. Benralizumab, administered subcutaneously, is already FDA approved to treat eosinophil-associated asthma. The primary objective of the Benralizumab Eosinophilic Gastritis (BEG) study is to assess the efficacy of repeat subcutaneous doses of benralizumab, compared with placebo, to reduce eosinophilic inflammation in the gastrointestinal tract. The secondary objectives of the BEG study include assessing changes in endoscopic score, histologic features, blood eosinophil counts, clinical symptoms, and expression of genes (as assessed by whole-genome RNA sequencing). Eligible subjects are children and adults between the ages of 12-60 years with active EG.

Cadherin-like 26

One of the molecules highly increased in the stomach of patients with eosinophilic gastritis (EG) was cadherin-like 26 (CDH26). Think of cadherins as velcro between cells, with each cadherin protein acting like a hook that snags cadherin on other cells. This attaches cells to each other. CDH26 was also increased in the esophagus of patients with eosinophilic esophagitis (EoE) so it may have a common function in different types of eosinophilic gastrointestinal disorders (EGIDs). Julie Caldwell, PhD, under the mentorship of Marc Rothenberg, MD, PhD, investigated CDH26 further and found that CDH26 not only had a structural role in human gastrointestinal tissue, but also had an immunoregulatory role during allergic responses. CDH26 bound to integrins to regulate leukocyte adhesion and activation, a critical step in immune cell recruitment to tissue. By identifying and determining the involvement of how factors that are differentially regulated in EGIDs, such as CDH26, in these disorders, we may be able to develop better diagnostic tools and treatments related to these molecules in the future.

Loss of Tissue Identity

In the differentiation process, cells in the body become more specified, transitioning from less mature cells with more potential fates to more mature cells with more specialized functions and identity. An esophageal epithelial cell is a highly specified cell, but one that may explain the mystery of the tissue specificity in eosinophilic gastrointestinal disorders (EGIDs), allergic conditions of the gastrointestinal tract. Mark Rochman, PhD, under the mentorship of Marc Rothenberg, MD, PhD, investigates whether tissue identity and differentiation state were a part of the pathogenesis of eosinophilic esophagitis (EoE), the most common of the EGIDs. They found that a profound loss of differentiation or identity in esophageal epithelial tissue was a key part of EoE pathogenesis.>

Eosinophilic Esophagitis Genetic Susceptibility Mediated by Synergistic Interactions Between Disease-specific and General Atopic Disease Loci

Eosinophilic esophagitis (EoE) is an esophageal inflammatory disease associated with atopic diseases. Genetic variations and environmental exposures contribute to EoE, but how identified EoE risk variants, such as those in thymic stromal lymphopoietin (TSLP) and calpain 14 (CAPN14), relate to atopy or interact is unclear. Currently, genetic risk variants for EoE have uncovered key pathways involved in disease pathogenesis but are not associated with susceptibility risk factors large enough to be useful for clinical decisions. In an original research study, Marc Rothenberg, MD, PhD, and colleagues investigated whether carrying combinations of genetic risk factors would increase disease risk, perhaps enough to be clinically useful. They explored the relationship between EoE, atopy, and genetic risk. Cohorts of patients with EoE with and without atopy and community controls used to test for whether atopy enriches in patients with EoE, what genetic variants specifically associate with risk of EoE, and how EoE-specific and atopy-related genetic variants interact. They found that enriched atopic disease in patients with EoE. Patients with atopy were more likely to carry risk alleles for the interleukin 4/kinesin family member 3A (IL4/KIF3A) locus. On the other hand, variants in TSLP and CAPN14 were specifically associated with EoE. Importantly, there was a notable interaction between genetic risk variants in IL4/KIF3A and TSLP. Having the risk allele for IL4/KIF3A or TSLP associates with modest risk of EoE but having both associated with relatively high risk of EoE (i.e., 3.6-fold increased risk). These findings support the mediation of EoE genetic susceptibility by synergistic interactions between EoE-specific and general atopic disease loci and help explain the high degree of atopic disease comorbidity in children with EoE. Identifying these effects may help to better predict disease susceptibility and bring EoE closer to benefiting from precision medicine.

Environmental Factors Could Adjust Risk for Eosinophilic Esophagitis in People with Particular Gene Variants

In collaboration with national researchers, Marc Rothenberg, MD, PhD, investigated how early-life environmental exposures interact with genetic susceptibility variants in pediatric patients with eosinophilic esophagitis (EoE). The study followed 127 subjects with EoE and 121 control subjects, all recruited from the Cincinnati Center for Eosinophilic Disorders at Cincinnati Children’s. Subjects with and without EoE were all under the age of 18 at time of enrollment and were self-reported Caucasian. They all had a DNA sample taken and their mothers asked to fill out a questionnaire describing early life experiences. The study results are notable in that the risk of developing EoE, in people with two gene variants associated with developing the disease, modification by certain environmental exposures could potentially occur. The research suggested that people with gene variants in CAPN14 or LOC283710/KLF13 breastfed or admitted to a neonatal intensive care unit were significantly less or more likely to develop the disease. Notably, breastfed people with a gene variant in the CAPN14 gene were 92% less likely to develop EoE compared to patients who had the gene variant but were not breastfed. Though the underlying mechanism for how breastfeeding and CAPN14 may interact and protect against EoE is unknown, the association ofCAPN14 with barrier function in the gut, suggesting that breastmilk’s preventive role may relate to the setting of altered barrier function. The study also suggests that admission into a neonatal intensive care unit can significantly increase the odds of developing EoE in people with a gene variant at LOC283710/KLF13. Though the evidence is preliminary, further understanding of these interactions could provide an opportunity to alter the development of EoE, as some environmental factors are modifiable in individuals harboring specific genetic variants.

Whole-exome Sequencing Uncovers Oxidoreductases and Hints at Mitochondrial Dysfunction in Eosinophilic Esophagitis

Eosinophilic esophagitis (EoE) is a chronic allergic disorder that presents with difficulty swallowing, vomiting, failure to thrive, and food impaction in adulthood. Even with the identification of several EoE-associated pathways the underlying genetic causes of this disorder are poorly understood. In this publication, Marc Rothenberg, MD, PhD, and colleagues used whole-exome sequencing and family-based trio analysis to identify EoE-associated variants in the mitochondrial oxidoreductases DHTKD1 and OGDHL. In T cells, loss of DHTKD1 function increased reactive oxygen species and viperin, which promotes Th2 cytokine production. Moreover, there was an increase of viperin in esophageal biopsies from patients with EoE. Together, these results implicate mitochondrial dysfunction in EoE pathogenesis. Thus, this translational research identified a series of rare genetic variants implicating the oxidoreductases DHTKD1 and OGDHL in the genetic etiology of EoE, an allergic inflammatory esophageal disorder with a complex underlying genetic etiology, and underscore a potential pathogenic role for mitochondrial dysfunction in EoE.

Division Director Gives Meaningful Keynote in Austria

Named after the visionary researcher and internationally renowned founder of neuromedicine, the Otto Loewi Research Centre for Vascular Biology, Immunology and Inflammation celebrated its official opening at the Medical University of Graz. Director of the Division of Allergy and Immunology at Cincinnati Children’s, Marc Rothenberg, MD, PhD, gave the Otto Loewi Memorial Lecture, in memory of the 1936 Nobel Laureate in Medicine, for the discovery of neuromediators (acetylcholine). In addition to Dr. Loewi’s scientific contributions, which are still impacting patients today, such as the usage of neuromediators in the allergy field (e.g., adrenaline for anaphylaxis and acetylcholine inhibitors for bronchodilation), Dr. Loewi’s plight as a Jewish person in Nazi-controlled Austria was notable. The arrest of Dr. Loewi and the stripping of his faculty position occurred despite being the Chairman of Physiology at the Medical School and the Nobel Laureate two years earlier. Released from prison only by handing over all of his assets, including his house and funds from the Nobel Prize, he was subsequently permitted to leave Austria. Prior to Dr. Rothenberg’s lecture was the dedication and ribbon-cutting ceremony of a new research building and institute that will bear Otto Loewi’s name. After the official opening of the ceremony, the Rector of the University gave his greetings and spoke about the center's namesake and Dr. Loewi’s work in Graz before his expulsion by the Nazis, delivering a most moving speech indicating that naming the building after Otto Loewi is so that the atrocities against the Jews, carried out in the very premises of the medical school, will never happen again.

Consortium for Eosinophilic Gastrointestinal Researchers CEGIR

In its fourth year, the Consortium of Eosinophilic Gastrointestinal Disease Researchers (CEGIR) received recognition by various sources for its amazing patient advocacy efforts, teamwork, and structure. CEGIR is the first large-scale collaboration between key stakeholders in the field of eosinophilic gastrointestinal disorders, including researchers, patients and the key funding agency, the National Institutes of Health (NIH), and dedicates itself to improving the lives of individuals with eosinophilic gastrointestinal disorders through innovative research, clinical expertise and education via collaborations between scientists, health care providers, patients, and professional organizations. A published summary of the formation of CEGIR, “Creating a multi-center rare disease consortium – the Consortium of Eosinophilic Gastrointestinal Disease Researchers (CEGIR)” is in Translational Science of Rare Diseases. There are two articles featuring CEGIR publications in the Spotlight on Rare Diseases publication of the Rare Diseases Clinical Research Network: “CEGIR - Improving research of eosinophilic gastrointestinal disorders with the patient perspective” and “CEGIR - Changing the paradigm in research of eosinophilic gastrointestinal disorders”.

Study Finds Absence of Key Protein May Drive Eosinophilic Esophagitis: Replacement Therapy Reversed Effects in Tissue Experiments

Absence of a specific protein in cells lining the esophagus may cause inflammation and tissue damage in people with eosinophilic esophagitis (EoE). The protein, SPINK7, was nearly absent in esophageal biopsies from people with active EoE but was prevalent in healthy esophagi, where it damped down inflammation and helped preserve tissue structure. Encouragingly, an available therapeutic reversed damaging inflammation in tissues that lacked SPINK7. Because foods we eat contain enzymes that can damage human tissue, the lining of the esophagus protects itself by producing its own enzymes that degrade the offending proteins and thus protect the lining. Nurit Azouz, PhD, under the mentorship of Marc Rothenberg, MD, PhD, found that SPINK7 is a key contributor to this protective process and was nearly absent in the esophagi of adults and children with EoE. By silencing or removing SPINK7, the gene that codes for SPINK7, in cultures derived from esophageal tissues, they discovered that large gaps formed between cells lining the esophagus and that these cells lost their normal barrier function that ordinarily helps move food along the digestive tract. Tissues that did not express SPINK7 also produced high levels of chemical messengers called cytokines that attract and activate eosinophils and produce the same type of inflammation seen in allergic diseases The researchers then treated esophageal tissue samples with alpha-1 anti-trypsin, or A1AT, a biologic drug approved to treat a genetic form of emphysema. Like SPINK7, A1AT is a natural inhibitor of tissue-damaging proteins called proteases. In the lab, A1AT reversed the damaging inflammation seen in tissues that lacked SPINK7, warranting the suggestion of further investigation to determine whether this therapeutic may also benefit people with EoE. Currently, people with EoE may take corticosteroids to relieve inflammatory symptoms, restrict their diets to avoid allergen containing foods that drive EoE or undergo periodic surgical procedures to expand the esophagus. (Listen to the podcast “Absence of Key Protein, SPINK7, May Drive Eosinophilic Esophagitis”, Marc E. Rothenberg, MD, PhD.)