American Academy of Allergy, Asthma & Immunology: Virtual annual meeting, February 26 to March 1, 2021

Abstract

After last year’s cancellation due to the pandemic, the annual meeting of the American Academy of Allergy, Asthma and Immunology was held at the end of February and provided an opportunity for clinicians and scientists to share the results of their research and learn about new and emerging therapies. In addition to the topics traditionally covered at the conference, e.g. therapies for allergic diseases, mechanisms of allergic inflammation, asthma or atopic dermatitis, research related to COVID-19 and COVID-19 vaccines (immunological profile, vaccine development, vaccine allergy etc.) were, unsurprisingly, extensively discussed. Below are a handful of studies presented during the scientific sessions and representative of the diversity of this conference. Can the variable clinical phenotype of selective IgA deficiency be explained by gut microbiome/immune system interactions? Peyton Conrey, along with co-first authors Lidiya Denu and Kaitlin O’Boyle, as part of a collaboration between Dr. Sarah Henrickson and Dr. Michael Silverman’s labs at the Children’s Hospital of Philadelphia, Pennsylvania, USA, shared findings of a comparative study between patients with selective immunoglobulin A (IgA) deficiency and controls. While being the most common primary immune deficiency, only a third of affected patients are symptomatic and present with increased rates of allergy, infection and/or autoimmunity. In order to explain this variability in clinical phenotype, Ms. Conrey and her colleagues investigated the potential impact of IgA on the ability of gut microbes to access the systemic immune compartment. To identify a potential link between the immune system and the gut, a cohort of 15 pediatric patients with selective IgA deficiency was recruited alongside a cohort of 17 controls composed of unaffected siblings of the patients living in the same household. Blood and stool samples were collected and used to perform high dimensional immune profiling, microbial flow cytometry and metagenomic sequencing. Specifically, patient’s or control’s serum was added to their stool microbes and antibody binding to these microbes was measured by microbial flow cytometry. Stool microbes were then sorted and sequenced. Significant alterations of the immune phenotype were observed with an increase in inflammatory cytokines, and a decrease in IgA+ and IgG+ B cells in patients. The access of commensal gut microbes to the systemic immune compartment was also affected with an absence of IgA-bound microbes but a higher proportion of IgG-bound microbes, confirming the initial hypothesis. The