Abstract:

Objective To investigate the association between CHI3L1 polymorphism and asthma in the Han population of Guangdong,and to explore the clinical values of chitinase-like protein YKL-40 in evaluating disease severity and monitoring the progression of the disease.Methods Total 251 objects were divided into asthma group(n=150) and control group(n=101).The single nucleotide polymorphism (SNP) at CHI3L1 gene was detected with Massarray method.The serum YKL-40 levels,total IgE levels,peripheral blood eosinophil percentage(Eos%) of the objects in asthma and control groups were detected.The asthma patients were divied into asthma exacergation group and stable group, and the serum YKL-40 levels were  compared.Results The distribution
of A/G at rs3806448 of CHI3L1 had  significant difference between asthma and control groups(P<0.01),and the frequency of A allele at rs3806448 of the pati
ents in asthma group was significantly higher than that in control group(OR= 1.93,95% CI=1.30－2.62,χ2=11.6,P<0.01).The serum YKL-40 levels，total IgE and Eos% of the patients with AA at rs3806448 were higher than those of the  patients with GG or AG at rs3806448 (P<0.05);the FEV1% of the patients with AA was lower than those of the patients with GG or AG at rs3806448(P<0.01).The serum YKL-40 level  of the patients in asthma group was significantly highe
r than that in normal control group(P<0.01),and the serum YKL-40 level of the patients in asthma exacergation group was higher than those in asthma stable group and normal control group(P<0.01).The serum YKL-40 level of the patients in asthma group was positively correlated with the peripheral blood Eos% and total IgE level(rEos=0.348，rIgE=0.437，P<0.01),and was negatively correlated with the lung function(r=－0.745，P<0.01). Conclusion
The polymorphism of CHI3L1-rs3806448 may correlate with asthma of Han population in Guangdong area.The serum YKL-40 may be a new biomarker to
 evaluate asthma disease severity and helpful for monitoring illness stage.

Key words: bronchial asthma, single nucleotide polymorphism, chitotriosidase 3-like 1