T follicular helper cell expansion and hyperimmunoglobulinemia with spontaneous IgE production to dietary antigens in IgA-deficient mice.

Immunoglobulin A (IgA), the most abundantly produced antibody at mucosal surfaces, is thought to play key roles in immune responses to respiratory and enteric pathogens and in the regulation of commensal colonization. Low IgA levels have been associated with recurrent infections and immune dysregulation, including inflammatory bowel disease and autoimmunity. Levels of IgA in maternal breast milk and infant stool are both inversely associated with the emergence of immune responses to food antigens in infants and, in naturally resolving food sensitivity and immunotherapy protocols, the induction of IgA antibodies to dietary antigens has been associated with the acquisition of food tolerance.

Allergen-specific IgA and IgG antibodies as inhibitors of mast cell function in food allergy.

Food allergy, a group of adverse immune responses to normally innocuous food protein antigens, is an increasingly prevalent public health issue. The most common form is IgE-mediated food allergy in which food antigen-induced crosslinking of the high-affinity IgE-receptor, FcεRI, on the surface of mast cells triggers the release of inflammatory mediators that contribute to a wide range of clinical manifestations, including systemic anaphylaxis. Mast cells also play a critical function in adaptive immunity to foods, acting as adjuvants for food-antigen driven Th2 cell responses.

Rethinking Immunological Risk: A Retrospective Cohort Study of Severe SARS-Cov-2 Infections in Individuals With Congenital Immunodeficiencies.

Background: Debates on the allocation of medical resources during the coronavirus disease 2019 (COVID-19) pandemic revealed the need for a better understanding of immunological risk. Studies highlighted variable clinical outcomes of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infections in individuals with defects in both adaptive and innate immunity, suggesting additional contributions from other factors. Notably, none of these studies controlled for variables linked with social determinants of health.

Rethinking immunologic risk: a retrospective cohort study of severe SARS-CoV-2 infections in individuals with congenital immunodeficiencies.

Background: Debates on the allocation of medical resources during the COVID-19 pandemic revealed the need for a better understanding of immunologic risk. Studies highlighted variable clinical outcomes of SARS-CoV-2 infections in individuals with defects in both adaptive and innate immunity, suggesting additional contributions from other factors. Notably, none of these studies controlled for variables linked with social determinants of health.

IgG:FcγRIIb signals block effector programs of IgE:FcεRI-activated mast cells but spare survival pathways.

Background: IgE-induced mast cell (MC) degranulation can be inhibited by IgG antibodies, signaling via FcγRIIb, but the effects of IgG on IgE-induced MC transcription are unknown.

Objective: We sought to assess inhibitory IgG:FcγRIIb effects on MC responses to IgE using complementary transcriptomic and functional approaches.

Methods: RNA sequencing was performed on bone marrow-derived MCs from wild-type and FcγRIIb-deficient mice to identify genes activated following IgE receptor crosslinking that were further modulated in the presence of antigen-specific IgG in an FcγRIIb-dependent fashion.