Caesarean Section is associated with reduced perinatal cytokine response, increased risk of bacterial colonization in the airway, and infantile wheezing

Background: the relationship between cesarean section (CS) and allergic disorders such as asthma and wheezing has been inconsistent, and the mechanisms for their connection remained largely unknown. We aimed to investigate whether CS is associated with infantile wheeze and to explore the correlation between CS and several risk factors known to relate with development of allergy.

Method: Mononuclear cells were isolated from cord blood and assessed for TLR-triggered TNF-a, IL-6, and IL-10 responses by ELISA. Bacteria from nasopharyngeal specimens were identified with traditional culture methods at ages 1, 6, and 12 months. Infant lung function tests were performed at 6 and 12 months. Total and specific IgE, and clinical outcomes were assessed at 12 months of age.

Results: children delivered by CS were associated with increased risk of wheezing (aOR: 1.89; 95% CI: 1.09 – 3.28) and decreased compliance of the respiratory system at 12 months of age (p = 0.045). CS was associated with reduced perinatal TLR1-2- triggered TNF-a and IL-6 response (p = 0.016 for TNF- a and p = 0.026 for IL-6). Children born by CS had significantly higher bacteria colonization rate by 12 months of age (aOR: 1.89; 95% CI: 1.11 -3.20). No difference was found in the atopic sensitization or total IgE level between the 2 groups.

Conclusion: our findings suggested that CS was associated with decreased pro-inflammatory cytokine response to TLR1-2 stimulation, followed by higher abundance of bacterial colonization in the airway during late infancy, thus increasing the risk of developing infantile wheezing.