Assessment of the immunotoxicological effects of GMOs has mainly focused on the allergenic potential of genetically modified proteins whereas general immunotoxicological investigations of whole GMOs are not described in the literature. This finding, together with the findings of a Bt-specific IgE response in humans working with Bt pesticides reported by Bernstein et al. and Doekes et al. highlights the importance of evaluating the sensitization of consumers, especially atopic fieldworkers, of ‘foreign’ proteins or GM food prior to their introduction to world market.