Peanut allergy inherited from allergic mothers

Researchers at the Mount Sinai School of Medicine in New York, USA, have used a mouse model to gain evidence of maternal transmission of peanut allergy susceptibility to their offspring.

They also investigated the effect of exposure to peanut during pregnancy and lactation on the development of peanut allergy in offspring. Results of their work indicate that maternal peanut allergy is a risk factor for developing peanut allergy. It also appears that exposure to small amounts of peanut during pregnancy and lactation can reduce the risk of peanut allergy developing in the offspring of peanut-allergic mothers.

The mouse models used in the research have been specifically bred to have IgE-mediated allergy to peanut. The female mice were sensitised with peanut and subsequently mated with non-allergic male mice. In one part of the study, the female mice were fed a normal, peanut-free diet throughout pregnancy and lactation. Three to four weeks after weaning, at the age of 5 weeks, their offspring were challenged with 200 mg/mouse of ground peanut.

Another part of the study was designed to test the impact of low exposure to peanut during pregnancy and lactation. For this, a group of peanut allergic pregnant female mice was divided into two. One group received feed containing low levels of peanut (10mg/mouse) for 5 weeks while the mice in the second group were given feed containing no peanut for the same period. At the age of 5 weeks, the offspring from both groups were given an oral challenge with peanut. The 5-week-old offspring from these groups were subsequently challenged with peanut intragastrically. In another subset of the experiment, offspring of both of these groups were sensitized with peanut intragastrically for 6 weeks, and serum peanut-specific antibodies were determined.

Results showed that offspring from the peanut allergic mice had anaphylactic allergic reactions on their first exposure to peanut. In the second experiment, offspring of the mice that had been fed peanut showed significantly reduced first-exposure reactions to peanut compared to the offspring of those mice that were fed a peanut-free diet. In the third component of the research, the offspring of mice fed with peanut showed a reduction in peanut-specific IgE to the active peanut sensitisation.

Reference: Lopez-Exposito et al.2009. Journal of Allergy and Clinical Immunology Vol 124(5) pp 1039-1046.