Researchers at the Helmholtz Center for Environmental Research in Leipzig, the Helmholtz Zentrum Munchen and the Institut fir Umweltmedizinische Forschung in Duesseldorf examined blood samples taken from 234 6-year-old children.

The researchers discovered increased blood concentrations of the stress-related peptide VIP -- vasoactive intestinal polypeptide -- in connection with moving to a new house or the separation of parents. The neuropeptide VIP could take on a mediator role between stress events in life and the regulation of immune responses, the researchers said.

The study, published in the journal Pediatric Allergy and Immunology, found in children, whose parents had separated over the last year, increased blood concentrations of the neuropeptide VIP as well as an increased concentration of immune markers, which are related to the occurrence of allergic reactions.