Abstract
Background: Chitinase family proteins are associated with airway inflammation in adults, yet it is unknown whether levels are altered in children with asthma. Our aim was to examine chitotriosidase (CHIT1) and YKL-40 (CHI3L1) as potential biomarkers of airway inflammation in children, taking into account possible effects of genetic variation.
Methods: Blood samples were obtained from children aged 6-18 with controlled (n=39) and severe (n=57) asthma, described in Konradsen et al. (Pediatric Allergy Immunology 2011;22:9-18). Serum chitotriosidase activity and YKL-40 levels were analysed in a subset of patients and compared to 41 healthy children. DNA samples were genotyped for a null 24bp duplication in CHIT1 and the CHI3L1 promoter SNP Rs4950928.
Results: YKL-40 levels were significantly greater in severe asthmatics compared to healthy children, whereas chitotriosidase activity was no different in asthmatics compared to controls. Genetic variation affected both YKL-40 levels and chitotriosidase activity. The CHI3L1 Rs4950928 CC allele was associated with greater levels of serum YKL-40 (24.3 (16.7-29.6)) than the CG allele (19.4 (14.9-23.3), p=0.008). Children lacking the 24bp duplication in CHIT1 showed greater chitotriosidase activity (68.0 (56.6-89.7)) than those heterozygous for the duplication (35.6 (26.9-41.8), p<0.001).
Conclusions: These results suggest that serum YKL-40 is a genetically influenced, potential new biomarker of airway inflammation in children.
- © 2011 ERS