Patterns of Immune Development in Urban Preschoolers with Recurrent Wheeze and/or Atopy

Along with wheezing illnesses, allergic sensitization during infancy is a major risk factor for childhood asthma.  But how exactly this allergic sensitization occurs is not very well known.  In this month’s issue of JACI, Gern and colleagues look at cytokine responses in 467 inner-city children from the URECA study (Urban Environment and Childhood Asthma) at ages 1 and 3 years (J Allergy Clin Immunol 2017; 140(3): 836-844).  They then examined these cytokine responses in relation to environmental exposures to allergens and endotoxin as well as development of allergic sensitization and recurrent wheezing.

They found that cytokine responses increased as the children grew older, but responses at birth were not predictive for responses at ages 1 and 3 years. Exposure to cockroach, mouse, and house dust mite was associated with enhanced Interferon-alpha and IL-10 cytokine responses.  This contrasts with reduced IL-10 responses at birth, which was associated with recurrent wheeze.  Atopy was associated with (1) reduced respiratory syncytial virus-induced IL-8 responses as well as (2) heightened CpG-induced IL-12p40 and 5’-cytosine-phosphate-guanine-3’ (CpG)-induced IL-12p40 and (3) increased allergen-induced IL-4 responses.  Altogether, these findings suggest that exposure to animal proteins and microbes stimulates the immune system early in life and modulates cytokine responses in ways that may be protective for childhood asthma.