Prenatal farm exposure is related to the expression of receptors of the innate immunity and to atopic sensitization in school-age children.

Background: There is increasing evidence that environmental exposures determining childhood illnesses operate early in life. Prenatal exposure to a farming environment through the mother might also play an important role.

Objective: We sought to investigate the role of maternal exposures to environments rich in microbial compounds for the development of atopic sensitization, asthma, and corresponding alterations in the innate immune system in offspring.

Microbial exposure of rural school children, as assessed by levels of N-acetyl-muramic acid in mattress dust, and its association with respiratory health.

Background: Endotoxin exposure has been shown to be associated with a decreased prevalence of atopic sensitization and symptoms. Yet endotoxin represents only a part of the indoor microbial exposure. Muramic acid, a constituent of peptidoglycan, is present in gram-negative and gram-positive bacteria in the environment and may therefore serve as an additional marker of microbial exposure.