The chitinase-like protein YKL-40 is not a useful biomarker for severe persistent asthma in children.
Santos CB, Davidson J, Covar RA, Spahn JD. The chitinase-like protein YKL-40 is not a useful biomarker for severe persistent asthma in children. Ann Allergy Asthma Immunol. 2014 Sep; 113(3):263-6.