Background: Allergy has been studied as a risk factor for several malignancies, including childhood leukemia; yet, the tentative etiological nature of this association needs to be further explored. Published studies suffer inappropriate study design and accuracy of exposure variables. In response to the latter need, this study aims to use country specific biological markers, namely levels of the most prevalent allergen-specific immunoglobulin E (IgE) antibodies in Greece as an alternative exposure measurement to history of allergy and compare their concordance with allergic history. Methods: Allergen-specific-IgEs against 24 most prevalent inhalant and food allergens were determined for 199 incident childhood acute lymphoblastic leukemia (ALL), newly diagnosed cases across Greece and registered in the Nationwide Registry for Childhood Hematological Malignancies (NARECHEM) and 113 hospital controls. K statistic was used to check the concordance between serum IgE specific allergens and allergic history overall, as well as among cases and controls. Results: Concordance between self-reported food allergy and food IgE levels in the same individual among both cases and controls was 87% and 83% for respiratory allergens. Among cases, concordance between self reported food allergies and food IgEs was 92% and 80% for controls (p-value 0.003) and the respective κ statistics were 0.28 for cases and 0.10 for controls. Concordance between self reported respiratory allergies and respiratory IgEs was 84% for cases and 81% for controls (p-value 0.57); κ statistics 0.09 for cases and 0.07 for controls. Conclusions: Much of the discordance among cases and controls (self-report false positives) might probably be a reflection of non allergic food hypersensitivity, an allergy that was surpassed or extended allergen avoidance. Other discordance (self-report false negatives) seems to be the result of food sensitization, either hypoclinical or not acknowledged as a type of allergy by mothers of the children. Nevertheless, these measurements jointly analyzed are valuable in exploring the stated hypothesis, especially in well designed prospective studies.
- country specific serum
- IgE reactivity profile
- allergic history
- acute lymphoblastic leukaemia