Events occurring in utero could influence the development of allergic immunity, according to researchers at the World Asthma Meeting.

Karen Rudolph, M.S., and colleagues from Lovelace Respiratory Research Institute, Albuquerque, N.M., sought to determine the importance of the allergic sensitization of parents on allergic susceptibility of offspring using a Beagle dog model of allergic asthma. A group of puppies was produced from female dogs with high levels of total IgE, but not sensitized to ragweed and a second group was produced from female dogs immunized to ragweed by injections. Puppies in both groups were immunized by injections of ragweed pollen extract within 24 hours of birth and through 22 weeks of life. Total IgE, and ragweed-specific IgE and IgG were measured during immunization, as well as 12 and 15 months of age. Airway hyperresponsiveness to histamine or ragweed was tested between 12 and 15 months.

Puppies from sensitized parents showed significantly higher ragweed-specific IgE levels, but lower ragweed specific IgG levels in serum in contrast to the offspring from non-sensitized dogs. Changes in airway resistance following a challenge of histamine or ragweed were significantly higher in dogs produced from sensitized parents.

Researchers concluded that while the data suggests that allergic sensitivity of female dogs is important in the development of allergic sensitivity of the offspring, it is not known whether allergen T cells, and/or allergen-specific antibody from the pregnant female is important in increasing the allergic sensitivity of the offspring.