Authors:
Lisciandro, J. G.; Prescott, S. L.; Nadal-Sims, M. G.; Devitt, C. J.; Pomat, W.; Siba, P. M.; Holt, P. G.;Strickland, D.; van den Biggelaar, A. H. J.
Authors notes:
Pediatric Allergy and Immunology. 2012;23(2):173-80
Keywords:
Australia, cord blood, hygiene hypothesis, neonatal, Papua New Guinea, T regulatory cell
Abstract:
Environmental changes, including declining microbial exposure, have been linked with the rising incidence of allergic and autoimmune diseases in 'western' populations. This potentially occurs by altering early development of immuno-regulatory pathways including T regulatory cells (T reg). There is now increasing evidence that such conditioning begins in utero.
We compared neonatal T reg from children born under typical western conditions (Australia, AUS) with those of neonates born under more traditional conditions of high microbial burden (Papua New Guinea, PNG).
The frequency of neonatal T reg, defined as CD4 + Foxp3 + CD127 - CD25 +/high was found to be higher in the cord blood of AUS compared to PNG newborns. However, cord T reg suppressive function in a small subset of children was qualitatively similar between PNG and AUS newborns in both a T reg depletion assay and a T reg supplementation assay.
These findings do not support the hypothesis that living in a 'western' versus more traditional environment leads to poor induction or suppressive function of neonatal T reg. However, environmentally-induced immuno-regulation may potentially occur via alternative mechanisms in PNG newborns that should now be investigated further.