Project description:BACKGROUND. Cow’s milk allergy (CMA) is the most common food allergy in young children. Treatment with oral immunotherapy (OIT) has shown efficacy but also high rates of adverse reactions. We sought to determine if baked milk (BM) OIT could reduce adverse reactions while still inducing desensitization, and to identify immunological correlates of successful BMOIT. METHODS. This phase II, randomized trial evaluated the safety and efficacy of BMOIT in children age 3-18 years. After the initial placebo-controlled first year of treatment, placebo-treated participants crossed over to active BMOIT for year two. Double-blind, placebo-controlled food challenges (DBPCFC) were conducted to BM after year one and to both BM and unheated milk (UM) after year two. IgG/IgE antibodies were measured along with cow’s milk (CM)-specific CD4 memory T cell populations, profiled using flow cytometry and scRNA-Seq. RESULTS. Twenty-one of 30 (70%) reached the primary endpoint of tolerating 4044mg of BM protein at month-24, and 11/30 tolerated ≥2000mg of UM. Dosing symptoms were common, but >98% were mild with no severe reactions. Immunological changes associated with desensitization included increased CM IgG4, CM+ FOXP3+ cells, and Tregs and corresponding decreases in CM IgE, CM+ Th2A cells, and CD154+ cells. T cell and antibody measurements were combined to build a model that predicted UM oral food challenge (OFC) outcomes. CONCLUSION. BMOIT was well tolerated and induced a substantial level of desensitization to baked and unheated milk. This desensitization corresponded to significant redistribution within antigen specific antibody and T cell compartments that provide novel insight into the mechanistic changes that occur with OIT treatment.
Project description:Genome wide DNA methylation profiling study of PBMC from 71 unique primary patient blood samples. The Illumina Human Methylation 450k array was used. 29 challenge proven food allergy, 29 sensitized but oral tolerant, 13 non food allergics Mixture of food allergy phenotypes (egg allergic (15), peanut allergic (14)), food sensitization phenotypes (egg sensitized (14), peanut sensitized (15)). 4 samples had technical replicate hybridzations. Bisulphite converted DNA from the 75 samples were hybridised to the Illumina Infinium 450k Human Methylation Beadchip v1.2. Technical replicates were combined during processing, resulting in normalized Beta values for 71 unique primary patient blood samples.
Project description:The objective of the study was to investigate how oral immunotherapy (OIT) for food allergy modulates inflammation and immune cell responses. The blood cell transcriptome of 50 children receiving egg OIT was profiled using peripheral blood mononuclear cell (PBMC) samples obtained at baseline and after 3 and 8 months of OIT.
Project description:A Randomized, Placebo-Controlled Trial of Intradermal Allergen Immunotherapy for Grass Pollen Allergy Background: Repeated intradermal injection of grass pollen (nanograms of allergen) suppresses allergen-induced cutaneous late phase responses, in keeping with effects of conventional high dose subcutaneous and sublingual immunotherapy. We evaluated the efficacy and safety of grass pollen intradermal immunotherapy for treatment of allergic rhinitis.Methods: We randomly assigned 93 adults with grass pollen allergic rhinitis to receive 7 pre-seasonal Intradermal allergen immunotherapy injections (containing 7 ng of Phl p 5 major allergen) or histamine control. The primary end point was daily combined symptom-medication scores during the 2013 pollen season. Skin biopsies were taken after the pollen season following an intradermal allergen challenge. Cutaneous late phase responses were measured 4 and either 7, 10 or 13 months post-treatment. Results No difference in the primary endpoint was observed between treatment arms (median difference, 14; 95% confidence interval [CI], -172.5 to 215.1; P=0.80). Amongst secondary endpoints, nasal symptoms measured with daily scores (median difference, 35; 95% CI, 4.0 to 67.5; P=0.03) and visual-analogue scales (median difference, 53; 95% CI, -11.6 to 125.2; P=0.05) were higher in the intradermal treatment group. Intradermal immunotherapy increased serum Phl p-specific IgE (P=0.001) compared to the control arm and T cells cultured from biopsies showed higher and lower surface of surface markers for Type 2 (P=0.04) and Type 1 (P=0.01) T-helper cells, respectively, Interleukin-5 was differentially expressed by microarray (P=0.03). Late phase responses were still inhibited 7 months after treatment (P=0.03) but not at 10-13 months. Conclusions Grass pollen intradermal allergen immunotherapy was not clinically effective but resulted in immunological priming and worsening of allergic rhinitis symptoms.
Project description:MS/MS analysis of the peanut protein extract (PPE) confirmed the presence of the four major peanut allergens and identified the presence of Ara h 1 isotypes, Ara h 2 isotypes, Ara h 3 isotypes, Ara h 6 isotypes and Ara h 7 isotypes. Allergen-specific immunotherapy (IT) is emerging as a viable option for treatment of peanut allergy. Yet, prophylactic IT remains unexplored despite early introduction of peanut in infancy was shown to prevent allergy. There is a need to understand how allergens interact with the immune system depending on the route of administration, and how different dosages of allergen may protect from sensitisation and a clinical active allergy. Here we compared peanut allergen delivery via the oral, sublingual (SL), intragastric (IG) and subcutaneous (SC) routes for the prevention of peanut allergy in Brown Norway (BN) rats. BN rats were administered PBS or three different doses of PPE via either oral IT (OIT), SLIT, IGIT and SCIT followed by intraperitoneal (IP) injections of PPE to assess the protection from peanut sensitisation. The development of IgE and IgG1 responses to PPE and the major peanut allergens were evaluated by ELISAs. The clinical response to PPE was assessed by an ear swelling test (EST) and proliferation was assessed by stimulating splenocytes with PPE. Low and medium dose OIT (1 and 10 mg) and all doses of SCIT (1, 10, 100 µg) induced sensitisation to PPE, whereas high dose OIT (100 mg), SLIT (10, 100 or 1000 µg) or IGIT (1, 10 and 100 mg) did not. High dose OIT and SLIT as well as high and medium dose IGIT prevented sensitisation from the following IP injections of PPE and suppressed PPE-specific IgE levels in a dose-dependent manner. Hence, administration of peanut protein via different routes confers different risks for sensitisation and protection from peanut allergy development. Overall, the IgE levels toward the individual major peanut allergens followed the PPE-specific IgE levels. Collectively, this study showed that the preventive effect of allergen-specific IT is determined by the interplay between the specific site of PPE delivery for presentation to the immune system, and the allergen quantity, and that targeting and modulating tolerance mechanisms at specific mucosal sites may be a prophylactic strategy for prevention of peanut allergy.
Project description:Food allergy is caused by allergen-specific IgE but little is known about the B cell memory of persistent responses. Here we describe in pediatric peanut allergy a population of CD23+IgG1 memory B cells that contains peanut-specific clones and generates IgE plasma cells on activation. Through single cell transcriptomics and B cell receptor (BCR) sequencing, we characterized FCER2/CD23+ IgG1 memory B cells co-expressing IL4R, IL13RA1, IGHE and carrying highly mutated BCRs. Further we found that peanut allergen (Ara h 2)-specific B cells were mostly IgG1 memory cells, carried highly mutated BCRs compared to diphtheria toxin-specific B cells, and expressed FCER2 and germlin IGHE. Our findings suggest that CD23+IgG1+ memory B cells transcribing IGHE are a unique memory population containing precursors for pathogenic IgE in food allergy.
Project description:Allergen-specific IgE antibodies mediate allergic pathology in diseases such as allergic rhinitis and food allergy. Memory B cells (MBCs) contribute to circulating IgE by regenerating IgE-producing plasma cells upon allergen encounter. We report a population of type 2 polarized MBCs defined as CD23hi, IL-4Rαhi, CD32low at the transcriptional and surface protein levels.