The 2011 AAAAI Annual Meeting highlights

Each year, the AAAAI Annual Meeting is attended by several thousand allergists, immunologists, related physicians, allied health professionals and industry representatives, and the extensive program features a diverse array of topics in the allergy and immunology field.

Two key clinical studies into food allergy that were presented at the 2011 meeting held in San Francisco in March are summarised in this issue of the Allergen Bureau eNews. The full program and abstracts presented at the five-day convention can be accessed at http://annualmeeting.aaaai.org/.

• Clinical screening for peanut allergy

  Researchers from John Hopkins University have found IgE responses to the Ara h2 or Ara h8 peanut proteins can correctly identify patients with peanut allergy in most cases. They suggest that such 'screening tests' may be used to avoid putting patients who do not have peanut allergy, including those who had outgrown their allergy, through unnecessary double-blind, placebo-controlled food challenges.

  The study looked at IgE responses to peanut extract and specific components Ara h1, h2, h3, and h8 in sera collected from 61 children who had undergone peanut food challenge between 2003-2010 at the Johns Hopkins Pediatric Allergy Clinic.

  IgE anti-Ara h2 was significantly elevated in the majority of patients who had failed the food challenge. Conversely, a high proportion of those who had passed the challenge were IgE anti-Ara h2 negative. By contrast, serum IgE anti-Ara h8 was higher in patients who had passed the food challenge. Responses to total peanut, Ara h1 and Ara h3 did not show any significant association with the challenge outcome.

  Further testing in broader populations is needed to determine whether these results can be reproduced.

  Reference: Johnson et al. 2011 AAAAI Annual Meeting. Abstract 267

• Order of birth and food allergy

  Parents of more than 13,000 Japanese schoolchildren aged 7 to 15 years completed questionnaires as part of a study which has indicated that first-born children may be more likely to develop certain types of allergies than their younger siblings.

  The results showed there was no significant difference in the prevalence of asthma or atopic dermatitis (a type of eczema) according to birth order, but the prevalence of allergic rhinitis, allergic conjunctivitis, and food allergy decreased based on birth order, from oldest to youngest. Four percent of first-borns had some type of food allergy compared with 3.5% of children born second and 2.6% of those born third. Interestingly, while the prevalence of food allergy decreased significantly as birth order increased, the prevalence of wheeze increased significantly with birth order.

  Based on these findings, the study authors suggest that food allergies may have their origins in the prenatal period in the womb.

  Reference: Kusunoki et al. 2011 AAAAI Annual Meeting. Abstract 525