Peanut allergy in Ghana: Elevated IgE with no symptoms
Published Online: June 13, 2013
Peanut allergy is often severe and potentially life-threatening. Research studies indicate that peanut allergy is on the rise worldwide particularly in industrialized countries. However, very little is known about the prevalence of peanut allergy in developing countries where peanut consumption is high and parasitic infections are widespread.
In a recent article in The Journal of Allergy & Clinical Immunology, Amoah et al report their investigation into peanut allergy among over 1,600 schoolchildren in Ghana, West Africa. They collected data on peanut-specific immunoglobulin E antibody (sIgE) levels, skin prick test (SPT) reactivity to peanut, and reported symptoms to peanut.
The researchers found that elevated levels of peanut-specific IgE did not translate into skin prick test reactivity or reported symptoms to peanut. In addition, high levels of sIgE were positively associated with being infected with the parasitic worm, Schistosoma haematobium. When analyzed in detail, peanut-specific IgE was shown not to recognize major peanut protein components linked to peanut allergy and was rather directed against clinically irrelevant sugar structures called cross-reactive carbohydrate determinants (CCD) found in plants and invertebrates. Interestingly, these anti CCD IgE antibodies were directed against antigens from Schistosoma haematobium and had poor biological activity.
These findings indicate that in Ghana where peanut consumption is frequent, elevated peanut-specific IgE levels may primarily be to clinically irrelevant cross-reactive carbohydrate determinants and may not result in skin reactivity or reported symptoms. Therefore, the diagnostic value of IgE antibody measurements in establishing peanut allergy in this and similar populations has to be re-evaluated. Overall, the findings indicate a need to establish good diagnostics for allergies in developing countries.
The Journal of Allergy and Clinical Immunology (JACI) is an official scientific journal of the AAAAI, and is the most-cited journal in the field of allergy and clinical immunology.