Research

Mode of delivery and cord blood cytokines: a birth cohort study

Ngoc P Ly^1,2 , Begoña Ruiz-Pérez¹ , Andrew B Onderdonk¹ , Arthur O Tzianabos¹ , Augusto A Litonjua^1,3 , Catherine Liang¹ , Daniel Laskey¹ , Mary L Delaney¹ , Andrea M DuBois¹ , Hara Levy^1,5 , Diane R Gold¹ , Louise M Ryan⁴ , Scott T Weiss¹ and Juan C Celedón^1,3

¹  Channing Laboratory, Department of Medicine, Brigham and Women's Hospital and Harvard Medical School, Boston, MA, USA

²  Division of Pediatric Pulmonary Medicine, Department of Pediatrics, Massachusetts General Hospital for Children and Harvard Medical School, Boston, MA, USA

³  Division of Pulmonary and Critical Care Medicine, Department of Medicine, Beth Israel Deaconess Medical Center, Boston, MA, USA

⁴  Department of Biostatistics, Harvard School of Public Health, Boston, MA, USA

⁵  Division of Pediatric Pulmonary Medicine, Children's Hospital of Boston and Harvard Medical School, Boston, MA, USA

author email corresponding author email

Clinical and Molecular Allergy 2006, 4:13doi:10.1186/1476-7961-4-13

Published:	26 September 2006

Abstract

Background

The mechanisms for the association between birth by cesarean section and atopy and asthma are largely unknown.

Objective

To examine whether cesarean section results in neonatal secretion of cytokines that are associated with increased risk of atopy and/or asthma in childhood. To examine whether the association between mode of delivery and neonatal immune responses is explained by exposure to the maternal gut flora (a marker of the vaginal flora).

Methods

CBMCs were isolated from 37 neonates at delivery, and secretion of IL-13, IFN-γ, and IL-10 (at baseline and after stimulation with antigens [dust mite and cat dander allergens, phytohemagglutinin, and lipopolysaccharide]) was quantified by ELISA. Total and specific microbes were quantified in maternal stool. The relation between mode of delivery and cord blood cytokines was examined by linear regression. The relation between maternal stool microbes and cord blood cytokines was examined by Spearman's correlation coefficients.

Results

Cesarean section was associated with increased levels of IL-13 and IFN-γ. In multivariate analyses, cesarean section was associated with an increment of 79.4 pg/ml in secretion of IL-13 by CBMCs after stimulation with dust mite allergen (P < 0.001). Among children born by vaginal delivery, gram-positive anaerobes and total anaerobes in maternal stool were positively correlated with levels of IL-10, and gram-negative aerobic bacteria in maternal stool were negatively correlated with levels of IL-13 and IFN-γ.

Conclusion

Cesarean section is associated with increased levels of IL-13 and IFN-γ, perhaps because of lack of labor and/or reduced exposure to specific microbes (e.g., gram-positive anaerobes) at birth.