YKL-40 levels in cord blood – Associations with respiratory symptoms and asthma in children?

Background: Humans do not express chitin, but express the enzymatically inactive chitinase-like protein YKL-40. Increased serum levels of YKL-40 have been identified in adult asthmatics and children with severe asthma. Whether YKL-40 levels in cord blood from newborns are predictive for later asthma in childhood is unknown. Aim: We aimed to assess whether YKL-40 levels in cord blood of unselected newborns are associated with respiratory symptoms in the first year of life and asthma or atopy at six years. Methods: In this prospective cohort study we measured YKL-40 levels in cord blood of 208 term-born children using an enzyme-linked immunosorbent assay (ELISA). Information on parental history and pregnancy were obtained at birth. Respiratory symptoms during the first year of life were assessed weekly by standardized telephone interviews. At the follow-up with 6 years, we assessed the asthma diagnosis and a prick test was performed. Association of prenatal factors with YKL-40 and the predictive value of YKL-40 for respiratory symptoms, allergic sensitization and asthma were calculated using regression analysis. Results: 197 children were followed through the first year, 156 (79%) attended the follow-up. Prenatal factors such as maternal atopy and maternal smoking were not associated with YKL-40 levels. There was no association of YKL-40 levels in cord blood with respiratory symptoms in the first year of life and asthma, atopy or prick test at 6 years. Conclusion: In this cohort of unselected infants, YKL-40 levels in cord blood do not appear to be affected by prenatal risk factors and are not associated with respiratory symptoms in the first year of life and asthma or atopy at school age.