Review of 2007 allergy research

A review just published by Sicherer and Leung highlights key advances in allergic skin disease, anaphylaxis, and hypersensitivity to foods, drugs, and insect venom, primarily from among more than 95 articles on these topics published in the Journal of Allergy and Clinical Immunology throughout 2007.

Their discussion of research relating to food allergy covers a broad range of topics, from the EuroPrevall initiative that highlighted difficulties in obtaining an accurate epidemiological picture of the burden of food allergy, to new clinical studies that indicate children may not be as likely to outgrow their milk and egg allergies by the age of 3-5 years as previously thought.

In 2007 many researchers applied themselves to characterising the structure of allergens to assist in diagnosis, prediction of cross-reactivity, reaction severity, and treatment of food allergens. As a result, scientists are closer to being able to predict the propensity for a protein to invoke an allergic reaction based on its structure, although the factors affecting reaction severity are still relatively unclear.

Similarly, it is still difficult to predict the risk of an individual developing an allergy. Many studies published in 2007 focussed on this area, and it appears the results remain inconclusive. The authors reviewed the results of the Tasmanian Asthma study which indicated at age 7 years, participants who had been exclusively breast-fed and had a history of maternal atopy were less likely to have asthma, but by age 14 years, the risk reversed, and by age 44 years, the participants were even more likely to have asthma. Other studies were also unable to produce conclusive evidence that maternal diet restrictions or late introduction of ‘high risk’ foods to infants provide a protective effect against the development of food allergies. Some of the studies reviewed related to the use of probiotics to reduce atopic disease, however the results do not support this as a promising area.

The use of advisory labelling was the focus of two studies published by the journal last year. One showed consumers tend to ignore advisory labels differentially (eg. expecting that the term ‘‘may contain peanut’’ indicates greater risk than ‘‘made in a facility that processes peanut’’). Assays of a sampling of products labelled with advisory warnings showed that peanut was detectable in 7% at clinically relevant amounts; therefore, contrary to the impressions held by consumers, the nature of the warnings did not correlate with risks of detecting peanut protein.

Further studies reviewed dealt with the apparent increase in incidence of allergy, with one study showing that prescription rates of self-injection epinephrine in the United States were generally higher in northern compared with southern regions. This led to the hypothesis of vitamin D insufficiency causing immunologic consequences that result in stronger atopic response. It will be interesting to hear of follow-up research in this area.

Sicherer and Leung’s paper provides a thorough overview of a diverse range of allergy research. A similar review was published by the authors in 2004, and both serve as useful resources to keep up to date with advances in this field.

The full paper, ‘Advances in allergic skin disease, anaphylaxis, and hypersensitivity reactions to foods, drugs, and insects in 2007’ is currently in press with the Journal of Allergy and Clinical Immmunology. Contact the Allergen Bureau for more information.