In the last decade, we have seen a significant acceleration in published research in the area of food allergy. The year 2022 was no different, with exciting research furthering our understanding – and creating new questions too. At the 2022 American College of Allergy, Asthma, and Immunology (ACAAI) annual meeting last fall, Dr. Matthew Greenhawt shared his top food allergy studies and reviews for the year, and I’ve pulled six of these articles specific to peanuts for you here. I’ve added my own commentary and summary thoughts for each paper:
1. Jones S, Kim E, Nadeau K, et al. Efficacy and safety of oral immunotherapy in children aged 1-3 years with peanut allergy (the Immune Tolerance Network IMPACT trial): a randomized double-blind, placebo-controlled study. Lancet. 339(10322):359-371.
A group of 146 peanut allergic children were randomly assigned to receive either peanut oral immunotherapy (n=96) or placebo (n=50). After 134 weeks of treatment, the subjects stopped therapy for 26 weeks and then underwent oral food challenge to determine whether desensitization was sustained in the absence of ongoing consumption. The study determined that the best outcome, highest rates of desensitization and remission of food allergy, was experienced by children under 4 years of age. There are multiple limitations to this study, including a small number of subjects in the youngest subgroup, high dropout rate during he avoidance period, and 20-27% of subjects not reaching the maximal maintenance dose of 2000mg peanut protein.
Bottom Line: Oral immunotherapy may be most effective when started in the first few years of life.
This study is a continuation of research looking at the potential of probiotics to enhance or improve outcomes of oral immunotherapy (OIT). Since gastrointestinal-related adverse reactions (AE) are the top complaint amongst those reporting AE, the hope is that probiotics might help reduce those symptoms and could positively impact outcomes. In this study, 118 children 1-10 years of age were randomized to receive PPOIT or OIT (there is also a placebo group for control). This study found no difference in outcomes between the OIT and PPOIT groups as measured by sustained unresponsiveness, desensitization, or immunological parameters such as peanut skin prick test, peanut-specific IgE, and peanut-specific . Limitations of the study include the exclusion of patients with severe anaphylaxis or poorly controlled asthma.
Bottom Line: The addition of probiotics to OIT does not appear to improve outcomes.
In this study, 393 peanut-allergic children were randomized to receive epicutaneous immunotherapy (EPIT) – often called “patch therapy” – or placebo for 6 months in a double-blind, placebo-controlled period followed by open-label active treatment. The study had good safety profile with only 4 participants discontinuing with the study due to adverse events (AE) and use of epinephrine in only 7 children during the course of the study. Limitations of this study include a small number of subjects with a history of severe anaphylaxis and anaphylaxis was not independently validated by double blind placebo-controlled food challenge.
Bottom Line: With options for treating and managing peanut allergy limited to avoidance or oral immunotherapy, this study shows potential for another treatment option for individuals and families managing peanut allergy.
In this review, the authors looked at 36 trials of immunotherapy mostly child participants (n=2,126) and found that oral immunotherapy successfully increased tolerance during therapy for those with peanut, milk, and egg allergy. In peanut allergy, the authors found that treatment with OIT did not increase adverse reactions. Epicutaneous immunotherapy was successful in increasing tolerance for participants with peanut allergy. There were not enough trials published using biologics with or without immunotherapy to determine the efficacy of this potential treatment at the time of the review. Limitations of this review include differences in methodologies used between studies and a lack of eligible studies in some areas, including biologics. The limited inclusion of subjects with a history of anaphylaxis further limits the applicability of the findings.
Bottom Line: There are multiple options for treating food allergies in the pipeline, but some, including biologics, remain limited to research studies.
This is a retrospective look at the change in peanut allergy prevalence in two population-based cross-sectional samples of infants aged 12 months were recruited 10 years apart general population (n=7209) (1933 in 2018-2019 and 5276 in 2007 – 2011) from before and after the infant-feeding recommendations changed in Australia – going from restricting to encouraging peanut consumption in the first year of life. The study found the prevalence of peanut allergy decreased from 3.1% in 2007-2011 to 2.6% in 2018-2019, however this was not a statistically significant reduction. Of note, the researchers indicated that there was a population wide increase in infants of East Asian ancestry in Australia and previous research has shown an increased risk for peanut allergy in this population. This is notable, since despite more babies of East Asian ancestry being part of the second group of infants, there was not a statistical increase in peanut allergy. The study also found that there was a lower risk of peanut allergy amongst infants who began eating peanut containing foods at 6 months or earlier, as compared to those who waited until closer to 12 months of age. It is important to remember that this is only a 1 year snapshot and that it may take time to see changes. On the plus side, this could show a plateau of prevalence and perhaps a decline will be seen in future. It’s also possible that early peanut introduction isn’t the only important factor in prevention. The limitations of the study include fewer children participating in skin prick test between the study years as well as minor differences in what was considered a risk factor for peanut allergy development. There is also the possibility that parent’s reports could be inaccurate, since the data was collected retrospectively.
Bottom Line: The early introduction of peanut containing foods to infants in Australia, utilizing their country’s guidelines to feed babies peanut foods in the first year of life, did not result in significant reduction of peanut allergy in the first year of implementation. This raises questions about the need to be specific about more precise timing of introduction (before 6 months), amount of peanut protein to feed babies, and ongoing feeding versus one-time introduction.
This paper is from the ongoing HealthNuts study (n=5,276) in Australia. In this study, 156 children had developed peanut allergy at the first year of life and 471 had developed allergy to raw eggs, and children who developed new sensitizations or food reactions after age 1 year were assessed for food sensitization and allergy (confirmed by oral food challenge when indicated) at the 6-year follow up. At 6 years of age, the children were reassessed for natural resolution, and it was found that 29% had outgrown their allergy to peanuts and 89% had outgrown their egg allergy. Factors associated with persistent peanut allergy (that which is not outgrown) was having an initial skin prick test (SPT) of 8 mm or larger, being co-sensitized to tree nuts, and early-onset severe eczema. Children with persistent peanut allergy at age 6 years were more likely to have at least 1 parent who was Asian; have an eczema diagnosis at age 1 year; show sensitization to at least 1 tree nut, 1 other type of food, or house dust mite, and have a lower cumulative reaction-eliciting does in peanut OFC at age 1 than did those with a resolved peanut allergy. Persistence of egg-allergy was marked by having a SPT of 4 mm or larger at 1 year of life, other food sensitizations, and early-onset severe eczema. Possible limitations to this study include loss of subjects at 6 years of age. A descriptive analysis revealed some differences between characteristics of those who participated at age 6 years and those lost to follow up. This suggested that there may be some attrition bias in the present study, particularly toward those with a history of allergic disease.
Bottom Line: In this large cohort, natural resolution of egg allergy was near 90%, while almost 30% of those with peanut allergy outgrew their allergy. This highlights the importance of ongoing monitoring of peanut allergy for resolution, even without intervention or treatment.