Desensitization and remission after peanut sublingual immunotherapy in 1- to 4-year-old peanut-allergic children: A randomized, placebo-controlled trial.

BACKGROUND: Prior studies of peanut sublingual immunotherapy (SLIT) have suggested a potential advantage with younger age at treatment initiation. OBJECTIVE: We studied the safety and efficacy of SLIT for peanut allergy in 1- to 4-year-old children. METHODS: Peanut-allergic 1- to 4-year-old children were randomized to receive 4 mg peanut SLIT versus placebo. Desensitization was assessed by double-blind, placebo-controlled food challenge (DBPCFC) after 36 months of treatment. Participants desensitized to at least 443 mg peanut protein discontinued therapy for 3 months and then underwent DBPCFC to assess for remission. Biomarkers were measured at baseline and longitudinally during treatment. RESULTS: Fifty participants (25 peanut SLIT, 25 placebo) with a median age of 2.4 years were enrolled across 2 sites. The primary end point of desensitization was met with actively treated versus placebo participants having a significantly greater median cumulative tolerated dose (4443 mg vs 143 mg), higher likelihood of passing the month 36 DBPCFC (60% vs 0), and higher likelihood of demonstrating remission (48% vs 0). The highest rate of desensitization and remission was seen in 1- to 2-year-olds, followed by 2- to 3-year-olds and 3- to 4-year-olds. Longitudinal changes in peanut skin prick testing, peanut-specific IgG4, and peanut-specific IgG4/IgE ratio were seen in peanut SLIT but not placebo participants. Oropharyngeal itching was more commonly reported by peanut SLIT than placebo participants. Skin, gastrointestinal, upper respiratory, lower respiratory, and multisystem adverse events were similar between treatment groups. CONCLUSION: Peanut SLIT safely induces desensitization and remission in 1- to 4-year-old children, with improved outcomes seen with younger age at initiation.

Open-label study of the efficacy, safety, and durability of peanut sublingual immunotherapy in peanut-allergic children.

BACKGROUND: Studies on the efficacy of peanut sublingual immunotherapy (SLIT) are limited. The durability of desensitization after SLIT has not been well described. OBJECTIVE: We sought to evaluate the efficacy and safety of 4-mg peanut SLIT and persistence of desensitization after SLIT discontinuation. METHODS: Challenge-proven peanut-allergic 1- to 11-year-old children were treated with open-label 4-mg peanut SLIT for 48 months. Desensitization after peanut SLIT was assessed by a 5000-mg double-blind, placebo-controlled food challenge (DBPCFC). A novel randomly assigned avoidance period of 1 to 17 weeks was followed by the DBPCFC. Skin prick test results immunoglobulin levels, basophil activation test results, TH1, TH2, and IL-10 cytokines were measured longitudinally. Safety was assessed through patient-reported home diaries. RESULTS: Fifty-four participants were enrolled and 47 (87%) completed peanut SLIT and the 48-month DBPCFC per protocol. The mean successfully consumed dose (SCD) during the DBPCFC increased from 48 to 2723 mg of peanut protein after SLIT (P < .0001), with 70% achieving clinically significant desensitization (SCD > 800 mg) and 36% achieving full desensitization (SCD = 5000 mg). Modeled median time to loss of clinically significant desensitization was 22 weeks. Peanut skin prick test; peanut-specific IgE, IgG4, and IgG4/IgE ratio; and peanut-stimulated basophil activation test, IL-4, IL-5, IL-13, IFN-γ, and IL-10 changed significantly compared with baseline, with changes seen as early as 6 months. Median rate of reaction per dose was 0.5%, with transient oropharyngeal itching being the most common, and there were no dosing symptoms requiring epinephrine. CONCLUSIONS: In this open-label, prospective study, peanut SLIT was safe and induced clinically significant desensitization in most of the children, lasting more than 17 weeks after discontinuation of therapy.

Irradiated Tree Nut Flours for Use in Oral Immunotherapy.

BACKGROUND: Tree nut allergies affect an estimated 1% of the US population and is lifelong in 90% of allergic individuals. Oral immunotherapy (OIT) for food allergies is an effective method to induce desensitization in a majority of participants in trials of peanut, egg, and milk OIT. Limited trials using tree nut OIT have been reported, possibly due to the lack of standardized drug products. OBJECTIVE: Food products used in OIT are considered drugs by the Food and Drug Administration (FDA) because they are intended to modulate the individuals' immune responses to the food allergens. As such, OIT drug products must meet FDA standards for acceptable levels of microbes and undergo testing for allergenic proteins. We aimed to determine the suitability of walnut, cashew, hazelnut, and almond flours for use in OIT trials. METHODS: We employed gamma irradiation on commercially available walnut, cashew, hazelnut, and almond flours and tested their levels of microbial contamination, total protein, and allergen content, along with stability of these parameters over time. RESULTS: Our results demonstrate that irradiation of tree nut flours greatly diminishes the levels of total aerobic bacteria, mold, yeast, Escherichia coli, and Salmonella, whereas there are no substantial changes in total protein or allergen content. Importantly, the microbial levels, protein, and allergen content remained stable over a 24-month period. CONCLUSION: Irradiation of tree nut flours is a safe and effective method of processing to allow tree nut products to meet the FDA standards for OIT drug products.

Food allergen extracts to diagnose food-induced allergic diseases: How they are made.

OBJECTIVE: To review the manufacturing procedures of food allergen extracts and applicable regulatory requirements from government agencies, potential approaches to standardization, and clinical application of these products. The effects of thermal processing on allergenicity of common food allergens are also considered. DATA SOURCES: A broad literature review was conducted on the natural history of food allergy, the manufacture of allergen extracts, and the allergenicity of heated food. Regulations, guidance documents, and pharmacopoeias related to food allergen extracts from the United States and Europe were also reviewed. STUDY SELECTIONS: Authoritative and peer-reviewed research articles relevant to the topic were chosen for review. Selected regulations and guidance documents are current and relevant to food allergen extracts. RESULTS: Preparation of a food allergen extract may require careful selection and identification of source materials, grinding, defatting, extraction, clarification, sterilization, and product testing. Although extractions for all products licensed in the United States are performed using raw source materials, many foods are not consumed in their raw form. Heating foods may change their allergenicity, and doing so before extraction may change their allergenicity and the composition of the final product. CONCLUSION: The manufacture of food allergen extracts requires many considerations to achieve the maximal quality of the final product. Allergen extracts for a select number of foods may be inconsistent between manufacturers or unreliable in a clinical setting, indicating a potential area for future improvement.

Preparation and Analysis of Peanut Flour Used in Oral Immunotherapy Clinical Trials.

BACKGROUND: Oral immunotherapy (OIT) is an investigational therapeutic approach for the treatment of food allergies. Characterization of the drug product used in oral immunotherapy trials for peanut allergy has not been reported. OBJECTIVE: To quantify relative amounts of the major peanut allergens and microbial load present in peanut flour used in OIT trials and assess whether these parameters change over a 12-month period. We also anticipate that this report will serve as a guide for investigators seeking to conduct OIT trials under Food and Drug Administration-approved Investigational New Drug applications. METHODS: Densitometric scanning of Ara h 1 and Ara h 2 resolved on SDS-PAGE gels was used to assess allergen content in peanut flour extracts. Microbial testing was conducted on peanut flour under US Pharmacopeia guidelines for the presence of Escherichia coli, salmonella, yeast, mold, and total aerobic bacteria. In addition, aflatoxin was quantified in peanut flour. Reported results were obtained from 4 unique lots of peanut flour. RESULTS: Relative amounts of the major peanut allergens were similar between different lots of peanut flour and remained stable over a 12-month period. E coli and salmonella were absent from all lots of flour. Yeast, mold, total aerobic bacteria, and aflatoxin were within established US Pharmacopeia guidelines on all lots tested and remained within the criteria over a 12-month period. CONCLUSIONS: Peanut flour used as a drug product contains the major peanut allergens and has low levels of potentially harmful microbes. Both these parameters remain stable over a 12-month period.

Neuronal nitric oxide synthase-dependent elevation in adiponectin in the rostral ventrolateral medulla underlies g protein-coupled receptor 18-mediated hypotension in conscious rats.

Direct activation of the endocannabinoid receptor G protein-coupled receptor 18 (GPR18) in the rostral ventrolateral medulla (RVLM) of conscious rats by abnormal cannabidiol (Abn CBD; trans-4-[3-methyl-6-(1-methylethenyl)-2-cyclohexen-1-yl]-5-pentyl-1,3-benzenediol) elevates local nitric oxide (NO) and adiponectin (ADN) levels and reduces oxidative stress and blood pressure (BP). However, the molecular mechanisms for GPR18-mediated neurochemical responses, including the nitric oxide synthase isoform that generates NO, and their potential causal link to the BP reduction are not known. We hypothesized that GPR18-mediated enhancement of Akt, extracellular signal-regulated kinase 1/2 (ERK1/2), and neuronal nitric oxide synthase (nNOS) phosphorylation, triggered by a reduction in cAMP, accounts for the NO/ADN-dependent reductions in RVLM oxidative stress and BP. Intra-RVLM GPR18 activation (Abn CBD; 0.4 µg) enhanced RVLM Akt, ERK1/2, and nNOS phosphorylation as well as ADN levels during the hypotensive response. Prior GPR18 blockade with O-1918 (1,3-dimethoxy-5-methyl-2-[(1R,6R)-3-methyl-6-(1-methylethenyl)-2-cyclohexen-1-yl]benzene) produced the opposite effects and abrogated Abn CBD-evoked neurochemical and BP responses. Pharmacological inhibition of RVLM phosphoinositide 3-kinase (PI3K)/Akt (wortmannin), ERK1/2 (PD98059 [2-​(2-​amino-​3-​methoxyphenyl)-​4H-​1-​benzopyran-​4-​one]), or nNOS (N(ω)-propyl-l-arginine), or activation of adenylyl cyclase (forskolin) virtually abolished intra-RVLM Abn CBD-evoked hypotension and the increases in Akt, ERK1/2, and nNOS phosphorylation and in ADN levels in the RVLM. Our pharmacological and neurochemical findings support a pivotal role for PI3K, Akt, ERK1/2, nNOS, and adenylyl cyclase, via modulation of NO, ADN, and cAMP levels, in GPR18 regulation of the RVLM redox state and BP in conscious rats.

The novel endocannabinoid receptor GPR18 is expressed in the rostral ventrolateral medulla and exerts tonic restraining influence on blood pressure.

Systemic administration of the G-protein-coupled receptor 18 (GPR18) agonist abnormal cannabidiol (Abn CBD) lowers blood pressure (BP). Whether GPR18 is expressed in the central nervous system (CNS) and plays a role in BP control is not known despite the abundance of the GPR18 ligand N-arachidonoyl glycine (NAGly) in the CNS. Therefore, we first determined whether GPR18 is expressed in the presympathetic tyrosine hydroxylase (TH) immunoreactive (ir) neurons of the brainstem cardiovascular regulatory nuclei. Second, we investigated the impact of GPR18 activation and blockade on BP and heart rate (HR) and neurochemical modulators of sympathetic activity and BP. Immunofluorescence findings revealed GPR18 expression in TH-ir neurons in the rostral ventrolateral medulla (RVLM). Intra-RVLM GPR18 activation (Abn CBD) and blockade (O-1918, 1,3-dimethoxy-5-methyl-2-[(1R,6R)-3-methyl-6-(1-methylethenyl)-2-,cyclohexen-1-yl]benzene) elicited dose-dependent reductions and elevations in BP, respectively, along with respective increases and decreases in HR in conscious male Sprague-Dawley rats. RVLM GPR18 activation increased neuronal adiponectin (ADN) and NO and reduced reactive oxygen species (ROS) levels, and GPR18 blockade reduced neuronal ADN and increased oxidative stress (i.e., ROS) in the RVLM. Finally, we hypothesized that the negligible hypotensive effect caused by the endogenous GPR18 ligand NAGly could be due to concurrent activation of CB(1)R in the RVLM. Our findings support this hypothesis because NAGly-evoked hypotension was doubled after RVLM CB(1)R blockade (SR141716, rimonabant). These findings are the first to demonstrate GPR18 expression in the RVLM and to suggest a sympathoinhibitory role for this receptor. The findings yield new insight into the role of a novel cannabinoid receptor (GPR18) in central BP control.