What if it is the other way around? Early introduction of peanut and fish seems to be better than avoidance

Reconceptualizing Integrated Knowledge Translation goals: a case study on basic and clinical science investigating the causes and consequences of food allergy

BACKGROUND

Integrated Knowledge Translation (IKT) and other forms of research co-production are increasingly recognized as valuable approaches to knowledge creation as a way to better facilitate the implementation of scientific findings. However, the nature of some scientific work can preclude direct knowledge to action as a likely outcome. Do IKT approaches have value in such cases?

METHODS

This study used a qualitative case study approach to better understand the function of IKT in a non-traditional application: basic and clinical science investigating the causes and consequences of food allergy. Building off previous baseline findings, data were obtained through in-depth interviews with project scientists and steering committee members and complemented by researcher observation. Data were analyzed through an integrated approach to understand how well participants perceived the stipulated project IKT outcomes had been met and to better understand the relationship between different forms of IKT goals, outcomes, and impacts.

RESULTS

We propose a conceptual model which builds temporal continuity into the IKT work and understands success beyond truncated timelines of any one project. The model proposes project IKT goals be conceptualized through three metaphorical tower blocks: foundational (changing the culture for both scientists and knowledge-users), laying the groundwork (building relationships, networks and sparking scientific inquiry), and putting scientific knowledge to action. Based on this model, this case study demonstrated notable success at the foundational and intermediate blocks, though did not turn basic and clinical research knowledge into actionable outcomes within the project timespan.

CONCLUSIONS

We find that current IKT literature which situates success as filling a knowledge to action gap is conceptually inadequate for understanding the full contributions of IKT activities. This work highlights the need for building cultural and scientific familiarity with IKT in order to better enable knowledge to action translation. Improving understanding and communication of science and empowering knowledge-users to engage with the research agenda are long-term strategies to build towards knowledge implementation and lay the ground work for many future research projects.

Late introduction of solids into infants' diets may increase the risk of food allergy development

Background

This study investigated risk factors associated with food allergy or food intolerance among school children in two Swedish towns.

Methods

Questionnaires were used to collect data on self-reported food allergy or intolerance (SRFA) in children aged 7–8 years from Mölndal in southwestern Sweden and Kiruna in northern Sweden. It included questions about specific food allergy or intolerance to cows’ milk, hens’ eggs, fish, peanuts, tree nuts, and cereals and also age of onset, type of symptoms and age of cessation. Information was also gathered on family allergy history, dietary habits, and certain lifestyle aspects.

Results

Of 1838 questionnaires distributed, 1029 were returned: 717/1354 (53%) from Mölndal and 312/484 (64%) from Kiruna. The cumulative incidence of SRFA was 19.6% with a significantly higher cumulative incidence in Kiruna (28.5%) than in Mölndal (15.7%), P < .001. Solids were introduced at a later age in Kiruna. Introduction of solids into a child’s diet from the age of 7 months or later, and maternal history of allergic disease, were both risk factors associated with a higher risk of food allergy or intolerance.

Conclusion

Late introduction of solids into an infant’s diet may be one risk factor for developing food allergy or intolerance. Later introduction of solids in Kiruna may be one explanation for the higher cumulative incidence of SRFA in that region.

Review suggests that the immunoregulatory and anti-inflammatory properties of allergenic foods can provoke oral tolerance if introduced early to infants' diets

For years, the advice was to postpone introducing allergenic foods, in order to prevent food allergies. However, food allergies have escalated rather than declined and our review of the latest epidemiological, immunological and nutritional research suggests that early weaning practices may be beneficial. The most allergenic foods, such as fish, eggs and peanuts, have proved to be inherently rich in tolerogenic substances that can play a significant role in preventing allergies.

CONCLUSION

We found evidence that the immunoregulatory and anti-inflammatory properties of allergenic foods can provoke oral tolerance if introduced early to both low-risk and high-risk infants.

Conflict or congruence? Maternal and infant-centric factors associated with shorter exclusive breastfeeding durations among the Tsimane

Six months of exclusive breastfeeding (EBF) is considered optimal for infant health, though globally most infants begin complementary feeding (CF) earlier-including among populations that practice prolonged breastfeeding. Two frameworks for understanding patterns of early CF emerge in the literature. In the first, maternal and infant needs trade-off, as "maternal-centric" factors-related to time and energy demands, reproductive investment, cultural influences, and structural barriers- favor supplanting breastfeeding with earlier and increased CF. A second framework considers that "infant-centric" factors-related to infant energetic needs-favor CF before six months to supplement breastfeeding. We apply these two frameworks in examining early CF among the Tsimane-a high-fertility, high-mortality, forager-horticulturalist population residing in the Bolivian Amazon. Data were collected from a mixed-longitudinal sample of 161 Tsimane mother-infant pairs from August 2012-April 2013. Tsimane mothers generally reported introducing CF because of perceived infant needs. However, CF is introduced with continued intensive breastfeeding, and generally coupled with premastication. Risks of earlier CF relative to the minimum hazard (estimated at 5 births) were elevated for lower and higher parity mothers, but were significantly greater only after 9 births. Seventeen percent of mothers reported introducing CF because of low milk supply. Introducing CF because of low milk was most common from 0 to 3 months of age and among higher parity mothers, which may reflect physiological constraints. Maternal reproductive trade-offs and perceived infant needs may help explain the low prevalence of EBF to six months among other populations in which breastfeeding is not structurally or culturally constrained.

Supplementation of Mice with Specific Nondigestible Oligosaccharides during Pregnancy or Lactation Leads to Diminished Sensitization and Allergy in the Female Offspring

BACKGROUND

The maternal environment and early life exposure affect immune development in offspring.

OBJECTIVE

We investigated whether development of food allergy in offspring is affected by supplementing pregnant or lactating sensitized or nonsensitized mice with a mixture of nondigestible oligosaccharides.

METHODS

Dams were sensitized intragastrically with ovalbumin before mating, with use of cholera toxin (CT) as an adjuvant. Nonsensitized dams received CT only. Dams were fed a control diet or a diet supplemented with short-chain galacto oligosaccharides (scGOSs), long-chain fructo oligosaccharides (lcFOSs), and pectin-derived acidic oligosaccharides (pAOSs) in a ratio of 9:1:2 at a dose of 2% during pregnancy or lactation, resulting in 7 experimental groups. After weaning, offspring were fed a control diet and ovalbumin-CT sensitized. Acute allergic skin responses (ASRs), shock symptoms, body temperature, and specific plasma immunoglobulins were measured upon intradermal ovalbumin challenge. Th2/Th1- and regulatory T cells were analyzed with use of quantitative polymerase chain reaction and flow cytometric analysis in spleen, mesenteric lymph nodes, and blood.

RESULTS

Supplementing sensitized pregnant or lactating dams with scGOS/lcFOS/pAOS resulted in lower ASRs in the offspring [offspring of sensitized female mice fed experimental diet during pregnancy (S-Preg): 48 ± 2.1 μm; offspring of sensitized female mice fed experimental diet during lactation (S-Lact): 60 ± 6.2 μm] compared with the sensitized control group (119 ± 13.9 μm). In the S-Lact group, this coincided with an absence of shock symptoms compared with the offspring of sensitized female mice fed control food during pregnancy and lactation (S-Con) and S-Preg groups, and lower ovalbumin-IgG1 [S-Con: 3.8 ± 0.1 arbitrary units (AUs); S-Preg: 3.3 ± 0.1 AUs; S-Lact: 2.4 ± 0.1 AUs] and higher ovalbumin-IgG2a concentrations (S-Con: 1.1 ± 0.1 AUs; S-Preg: 0.8 ± 0.1 AUs; S-Lact: 2.0 ± 0.1 AUs). Supplementing nonsensitized pregnant or lactating dams with scGOS/lcFOS/pAOS resulted in lower plasma ovalbumin-IgE [offspring of nonsensitized female mice fed experimental diet during pregnancy (NS-Preg): 1.6 ± 0.4 AUs; offspring of nonsensitized female mice fed experimental diet during lactation (NS-Lact): 0.3 ± 0.1 AUs vs. offspring of nonsensitized female mice fed control food during pregnancy and lactation (NS-Con): 3.1 ± 0.6 AUs] and ovalbumin-IgG1 (NS-Lact: 2.3 ± 0.3 AUs vs. NS-Con: 3.4 ± 0.3 AUs) concentrations in offspring. Ovalbumin-IgG2a plasma concentrations were higher in offspring of scGOS/lcFOS/pAOS-supplemented dams (NS-Preg: 1.1 ± 0.1 AUs; NS-Lact: 1.1 ± 0.1 AUs) than in those of unsupplemented, nonsensitized controls (0.4 ± 0.0 AUs).

CONCLUSIONS

These data show impaired sensitization in offspring of scGOS/lcFOS/pAOS-supplemented mice. A number of the analyzed variables are differentially affected by whether supplementation occurs during pregnancy or lactation, and the outcome of dietary supplementation is affected by whether the mother has been sensitized to ovalbumin and CT.

Peanut oral immunotherapy in adolescents: study protocol for a randomized controlled trial

Background

Peanut allergy is an increasingly common health problem. Current treatment guidelines are based on strict avoidance. However, in the last few years, oral immunotherapy protocols have shown promising results yielding increased tolerance to peanut in allergic children. Adolescence is particularly at risk.

Methods/Design

We have designed a randomized, double-blind, placebo-controlled, multicenter study to investigate the efficacy and safety of peanut oral escalating immunotherapy in a 12- to 18–year-old population with proved allergy to peanut. Patients are selected when the threshold of peanut intake is over 100 mg and 2 cumulated g on the first double-blind, placebo-controlled oral food challenge (DBPCOFC).

During the build-up placebo-controlled blinded phase, doses containing peanut or placebo will be administered by gradual up-dosing from 10 mg to 2 g with 2-weekly increments. After this first randomized phase, the desensitized participants will continue to intake native peanut in an unblinded process during 13 or 37 weeks following a second randomization. Adverse events are picked up and managed throughout the entire protocol.

The main endpoint is the percentage of patients with negative DBPCOFC at the threshold of 2 g of cumulative peanut at the end of the build-up phase of 24 weeks.

Secondary endpoints include: (1) desensitization 6 weeks and 6 months after the end of the maintenance phase; (2) adverse effects during the build-up phase; (3) immunological profile confirming peanut desensitization. Immunologic assays will be carried out at every DBPCOFC and at the middle of the build-up phase to evaluate the peanut immunologic profile modifications.

Discussion

This double-blind, placebo-controlled study will be, to our knowledge, the first evaluation of a peanut oral immunotherapy protocol in teenagers in the purpose to reduce severe reactions after unexpected intake and to improve quality of life.

Trial registration

ClinicalTrial.gov: NCT02046083 (23 January 2014).

Role of parental atopy in cow's milk allergy: a population-based study

BACKGROUND

A family history of atopy has been considered an independent risk factor for atopic diseases in children.

OBJECTIVE

To relate the risk of an infant developing IgE-mediated cow's milk allergy (IgE-CMA) to the atopic status of parents.

METHODS

Assessment of the parental atopic status of children with IgE-CMA (n = 66) previously identified in a large-scale prospective study was compared with the parental atopic status of a control group of healthy infants (n = 156). The atopic status was identified both by self-reporting and skin prick tests (SPTs).

RESULTS

Analysis for the risk for infants to develop IgE-CMA depended on the assessment method used. No significant differences were noted in self-reported parental atopic status between the IgE-CMA patients and the control group. However, among the subgroup of infants with persistent IgE-CMA (n = 25), maternal but not paternal self-reporting for atopy was more likely compared with parents of the control group (P = .04). In contrast, when analyzed by SPT, in both this persistent subgroup and the total allergic cohort, no significant differences were noted whether analyzed by single parent or both parents and whether the parent tested singly or multiply positive on the SPT.

CONCLUSION

In families with children with persistent IgE-CMA, self-reporting of atopy by parents may be biased. Furthermore, the demonstration of IgE-mediated responses to allergens in parents is insufficient by itself, in a general population cohort, to predict which infants are at greatest risk of developing IgE-CMA.

Potential mechanisms for the association between fall birth and food allergy

BACKGROUND

Season of birth has been reported as a risk factor for food allergy, but the mechanisms by which it acts are unknown.

METHODS

Two populations were studied: 5862 children from the National Health and Nutrition Examination Survey (NHANES) III and 1514 well-characterized food allergic children from the Johns Hopkins Pediatric Allergy Clinic (JHPAC). Food allergy was defined as self-report of an acute reaction to a food (NHANES), or as milk, egg, and peanut allergy. Logistic regression compared fall or nonfall birth between (i) food allergic and nonallergic subjects in NHANES, adjusted for ethnicity, age, income, and sex, and (ii) JHPAC subjects and the general Maryland population. For NHANES, stratification by ethnicity and for JHPAC, eczema were examined.

RESULTS

Fall birth was more common among food allergic subjects in both NHANES (OR, 1.91; 95% CI, 1.31-2.77) and JHPAC/Maryland (OR, 1.31; 95% CI, 1.18-1.47). Ethnicity interacted with season (OR, 2.34; 95% CI, 1.43-3.82 for Caucasians; OR, 1.19; 95% CI, 0.77-1.86 for non-Caucasians; P = 0.04 for interaction), as did eczema (OR, 1.47; 95% CI, 1.29-1.67 with eczema; OR, 1.00; 95% CI, 0.80-1.23 without eczema; P = 0.002 for interaction).

CONCLUSIONS

Fall birth is associated with increased risk of food allergy, and this risk is greatest among those most likely to have seasonal variation in vitamin D during infancy (Caucasians) and those at risk for skin barrier dysfunction (subjects with a history of eczema), suggesting that vitamin D and the skin barrier may be implicated in seasonal associations with food allergy.

What are the beliefs of pediatricians and dietitians regarding complementary food introduction to prevent allergy?

BACKGROUND

The timing of complementary food introduction is controversial. Providing information on the timing of dietary introduction is crucial to the primary prevention of food allergy. The American Academy of Pediatrics offers dietary recommendations that were updated in 2008.

OBJECTIVE

Identify the recommendations that general pediatricians and registered dietitians provide to parents and delineate any differences in counselling.

METHODS

A 9-item survey was distributed to pediatricians and dietitians online and by mail. Information on practitioner type, gender, length of practice and specific recommendations regarding complementary food introduction and exposure was collected.

RESULTS

181 surveys were returned with a 54% response rate from pediatricians. It was not possible to calculate a meaningful dietitian response rate due to overlapping email databases. 52.5% of all respondents were pediatricians and 45.9% were dietitians. The majority of pediatricians and dietitians advise mothers that peanut abstinence during pregnancy and lactation is unnecessary. Dietitians were more likely to counsel mothers to breastfeed their infants to prevent development of atopic dermatitis than pediatricians. Hydrolyzed formulas for infants at risk of developing allergy were the top choice of formula amongst both practitioners. For food allergy prevention, pediatricians were more likely to recommend delayed introduction of peanut and egg, while most dietitians recommended no delay in allergenic food introduction.

CONCLUSIONS

In the prophylaxis of food allergy, pediatricians are less aware than dietitians of the current recommendation that there is no benefit in delaying allergenic food introduction beyond 4 to 6 months. More dietitians than pediatricians believe that breastfeeding decreases the risk of atopic dermatitis. Practitioners may benefit from increased awareness of current guidelines.

Endogenous allergen upregulation: transgenic vs. traditionally bred crops

The safety assessment for transgenic food crops currently includes an evaluation of the endogenous allergy potential (via serum IgE screening) when the non-transgenic counterpart is a commonly allergenic food. The value of this analysis in the safety assessment of transgenic crops, especially with reference to recent requests to quantify individual allergen concentrations in raw commodities, is examined. We conclude that the likelihood of upregulating an endogenous allergen due to transgenesis is no greater than from traditional breeding which has a history of safety and is largely unregulated. The potential consequences of upregulating an endogenous allergen are also unclear.

Maternal peanut consumption provides protection in offspring against peanut sensitization that is further enhanced when co-administered with bacterial mucosal adjuvant

The aims of the present study were to assess whether protection against peanut (PN) sensitization can be conferred by maternal PN consumption alone and if so, whether protection was increased by mucosal adjuvant co-administration. Mice were fed with low dose of either PN or PN with cholera toxin (CT) preconceptionally, and during pregnancy and lactation. Offspring serum PN-specific immunoglobulins and cellular responses by splenocytes and mesenteric lymph node (MLN) cells were determined after an active PN sensitization protocol. Milk was collected from lactating mothers of 11-21-day-old pups for evaluation of PN-specific immunoglobulin levels. We found that offspring of PN fed mothers exhibited lower PN-specific IgE levels and reduced PN-stimulated splenocyte and MLN cells cytokine secretion than offspring of non PN fed mothers. CT co-administration with PN enhanced these responses.. Milk from mothers fed PN and CT, but not PN alone preconceptionally and during pregnancy and lactation contained markedly and significantly increased levels of both peanut-specific IgG2a and IgA. Our study demonstrated that maternal feeding of PN alone had a protective effect against PN sensitization of the progeny, which was enhanced by co-administration of a mucosal adjuvant. Increased levels of PN-specific IgG2a and/or IgA in milk were seen when PN and CT were administered together, suggesting that transmission of maternal immunoglobulins may play a role in the observed protection.

Food allergy and atopic eczema

PURPOSE OF REVIEW

To review recent developments on the inter-relationship between food allergy and atopic eczema, with a particular focus on understanding the role of filaggrin gene defects.

RECENT FINDINGS

Filaggrin gene defects have recently been identified as a major risk factor for the development of atopic eczema. These skin barrier defects increase the risk of early onset, severe and persistent forms of atopic eczema. They also increase the risk of allergic sensitization, and asthma and allergic rhinitis in those with co-existent eczema. These skin barrier defects are also likely to increase the risk of food allergy.

SUMMARY

Atopic dermatitis and food allergy are frequently herald conditions for other manifestations of 'the allergic march'. They commonly co-exist, particularly in those with early onset, severe and persistent atopic eczema. Filaggrin gene defects substantially increase the risk of atopic eczema. The increased skin permeability may increase the risk of sensitization to food and other allergens, this pointing to the possible role of cutaneous allergen avoidance in early life to prevent the onset of atopic eczema and food allergy. Emerging evidence also indicates that oral exposure to potentially allergenic foods may be important for inducing immunological tolerance.

Are peanut allergies a concern for using peanut-based formulated foods in developing countries?

BACKGROUND

Peanut allergy is relatively common among children in developed countries and may have severe outcomes, including anaphylaxis. However, few data about peanut allergy in developing countries are available. Meanwhile, formulated foods with peanuts as a major ingredient are being promoted to prevent and control malnutrition in developing countries.

OBJECTIVE

The objectives of the paper are to review the existing epidemiologic data about peanut allergy, to determine whether the prevalence of peanut allergy is lower in developing countries, and to explore the possible reasons for onset of peanut allergy.

METHODS

Publications relevant to peanut allergy were searched via Pubmed, and prevalence and etiological factors of peanut allergy were reviewed.

RESULTS

Data about peanut allergy were scarce in most developing countries. The existing data support the conclusion that peanut allergy is not as common in developing countries as in developed countries and may not be a major concern for programs promoting formulated food containing peanuts for control of malnutrition. However, plans for treatment of individuals with peanut allergy could be incorporated into these formulated food supplementation programs. A few risk factors (late introduction of peanuts to children, peanut processing technology, non-oral peanut exposure, and maternal peanut exposure during pregnancy and lactation) have been hypothesized to be associated with peanut allergy. However, more conclusive data are needed to verify or disprove these hypotheses.

CONCLUSIONS

Peanut allergy is not as common in developing countries as in developed countries and may not be a major concern for programs promoting formulated food containing peanuts for control of malnutrition. However, more research about prevalence of peanut allergy is warranted in developing countries.

Food allergy: separating the science from the mythology

Numerous genes are involved in innate and adaptive immunity and these have been modified over millions of years. During this evolution, the mucosal immune system has developed two anti-inflammatory strategies: immune exclusion by the use of secretory antibodies to control epithelial colonization of microorganisms and to inhibit the penetration of potentially harmful agents; and immunosuppression to counteract local and peripheral hypersensitivity against innocuous antigens, such as food proteins. The latter strategy is called oral tolerance when induced via the gut. Homeostatic mechanisms also dampen immune responses to commensal bacteria. The mucosal epithelial barrier and immunoregulatory network are poorly developed in newborns. The perinatal period is, therefore, critical with regard to the induction of food allergy. The development of immune homeostasis depends on windows of opportunity during which innate and adaptive immunity are coordinated by antigen-presenting cells. The function of these cells is not only orchestrated by microbial products but also by dietary constituents, including vitamin A and lipids, such as polyunsaturated omega-3 fatty acids. These factors may in various ways exert beneficial effects on the immunophenotype of the infant. The same is true for breast milk, which provides immune-inducing factors and secretory immunoglobulin A, which reinforces the gut epithelial barrier. It is not easy to dissect the immunoregulatory network and identify variables that lead to food allergy. This Review discusses efforts to this end and outlines the scientific basis for future food allergy prevention.

Has the time come to rethink the pathogenesis of asthma?

PURPOSE OF REVIEW

To explore new ground in asthma pathogenesis. Asthma is an inflammatory disorder of the airways that has strong association with allergy as characterized by a Th2-type T cell response. However, ranges of approaches that have targeted this immunological component have so far been disappointing. Most asthma therapy still relies on bronchodilators and corticosteroids rather than treating underlying disease mechanisms.

RECENT FINDINGS

In this review, a case is made that asthma has its primary origin in the airways that involves defective behaviour of the epithelium in relation to environmental exposures. These include defects in barrier function and an impaired innate immunity to provide the substrate upon which allergic sensitization can occur. Once the airways are sensitized repeated allergen exposure leads to disease persistence. Such mechanisms could explain airway wall remodelling and the susceptibility of the asthmatic lung to exacerbations provoked by viruses, air pollution, certain drugs, and biologically active allergens.

SUMMARY

Activation of the epithelial-mesenchymal trophic unit could be responsible for the emergence of different asthma phenotypes and direct a more targeted approach to treatment. There is also the possibility of developing treatments that increase the lung's resistance to the inhaled environment rather than focusing on the suppression of inflammation once established.

Clinical practice: Breastfeeding and the prevention of allergy

The increase in allergic disease prevalence has led to heightened interest in the factors determining allergy risk, fueled by the hope that by influencing these factors one could reduce the prevalence of allergic conditions. The most important modifiable risk factors for allergy are maternal smoking behaviour and the type of feeding. A smoke-free environment for the child (to be), exclusive breastfeeding for 4-6 months and the postponement of supplementary feeding (solids) until 4 months of age are the main measures considered effective. There is no place for restricted diets during pregnancy or lactation. Although meta-analyses suggest that hypoallergenic formula after weaning from breastfeeding grants protection against the development of allergic disease, the evidence is limited and weak. Moreover, all current feeding measures aiming at allergy prevention fail to show effects on allergic manifestations later in life, such as asthma. In conclusion, the allergy preventive effect of dietary interventions in infancy is limited. Counselling of future parents on allergy prevention should pay attention to these limitations.

A new look at the pathogenesis of asthma

Asthma is an inflammatory disorder of the conducting airways that has strong association with allergic sensitization. The disease is characterized by a polarized Th-2 (T-helper-2)-type T-cell response, but in general targeting this component of the disease with selective therapies has been disappointing and most therapy still relies on bronchodilators and corticosteroids rather than treating underlying disease mechanisms. With the disappointing outcomes of targeting individual Th-2 cytokines or manipulating T-cells, the time has come to re-evaluate the direction of research in this disease. A case is made that asthma has its origins in the airways themselves involving defective structural and functional behaviour of the epithelium in relation to environmental insults. Specifically, a defect in barrier function and an impaired innate immune response to viral infection may provide the substrate upon which allergic sensitization takes place. Once sensitized, the repeated allergen exposure will lead to disease persistence. These mechanisms could also be used to explain airway wall remodelling and the susceptibility of the asthmatic lung to exacerbations provoked by respiratory viruses, air pollution episodes and exposure to biologically active allergens. Variable activation of this epithelial-mesenchymal trophic unit could also lead to the emergence of different asthma phenotypes and a more targeted approach to the treatment of these. It also raises the possibility of developing treatments that increase the lung's resistance to the inhaled environment rather than concentrating all efforts on trying to suppress inflammation once it has become established.

Maternal peanut exposure during pregnancy and lactation reduces peanut allergy risk in offspring

BACKGROUND

Maternal allergy is believed to be a risk factor for peanut allergy (PNA) in children. However, there is no direct evidence of maternal transmission of PNA susceptibility, and it is unknown whether maternal peanut exposure affects the development of PNA in offspring.

OBJECTIVE

To investigate the influence of maternal PNA on offspring reactions to the first peanut exposure, and whether maternal low-dose peanut exposure during pregnancy and lactation influences these reactions and peanut sensitization in a murine model.

METHODS

Five-week-old offspring of PNA C3H/HeJ mothers (PNA-Ms) were challenged intragastrically with peanut (first exposure), and reactions were determined. In a subset of the experiment, PNA-Ms were fed a low dose of peanut (PNA-M/PN) or not fed peanut (PNA-M/none) during pregnancy and lactation. Their 5-week-old offspring were challenged intragastrically with peanut, and reactions were determined. In another subset of the experiment, offspring of PNA-M/PN or PNA-M/none were sensitized with peanut intragastrically for 6 weeks, and serum peanut-specific antibodies were determined.

RESULTS

PNA-M offspring exhibited anaphylactic reactions at first exposure to peanut that were associated with peanut-specific IgG(1) levels and prevented by a platelet activation factor antagonist. In a subset experiment, PNA-M/PN offspring showed significantly reduced first-exposure peanut reactions, increased IgG(2a), and reduced mitogen-stimulated splenocyte cytokine production compared with PNA-M/none offspring. In an additional experiment, PNA-M/PN offspring showed reduction of peanut-specific IgE to active peanut sensitization.

CONCLUSION

We show for the first time maternal transmission of susceptibility to first-exposure peanut reactions and active peanut sensitization. Low-dose peanut exposure during pregnancy and lactation reduced this risk.