Vitamin D deficiency during pregnancy has been linked to the development of childhood asthma, but most studies in this area have been observational. To directly examine how vitamin D status in pregnancy affects the neonatal immune system, Hornsby et al. analysed cord blood samples from neonates whose mothers had received daily vitamin D3 supplements during pregnancy. Cord blood mononuclear cells (CBMCs) from these neonates showed increased production of pro-inflammatory cytokines following activation with innate stimuli in vitro, and increased production of IL-17A in response to polyclonal T cell stimulation. Their CMBCs also produced greater amounts of IL-10 in response to dexamethasone treatment. The authors suggest that strong neonatal immune responses may protect against the development of asthma by improving respiratory health in early life.
Hornsby, E. et al. Vitamin D supplementation during pregnancy: effect on the neonatal immune system in a randomized controlled trial. J. Allergy Clin. Immunol. http://dx.doi.org/10.1016/j.jaci.2017.02.039 (2017)