YKL-40 is correlated with FEV(1) and the asthma control test (ACT) in asthmatic patients: influence of treatment

BACKGROUND: YKL-40 is also called chitinase-3-like-1 (CHI3L1) protein and may be a marker for asthma. The aims of the present study were to investigate whether serum YKL-40 levels are stable or decreased in patients with asthma after appropriate treatment and to evaluate the correlation of YKL-40 levels with lung function and asthma control test (ACT) results. METHODS: A total of 103 asthmatic patients (mean age 33.1 ± 0.9 years) with diagnosed asthma were enrolled in our study. All patients underwent a detailed clinical examination and completed the ACT questionnaire, serum YKL-40 measurement, and spirometry before (visit 1) and 8 weeks after initiation of treatment (visit 2). RESULTS: At the follow-up, the median serum YKL-40 level was significantly decreased compared to the levels at visit 1 (75.2 [55.8-86.8] ng/ml versus 54.5 [46.4-58.4] ng/ml, p < 0.001). The serum YKL-40 level was negatively correlated with %FEV(1) (r = -0.37, p < 0.001) and ACT score (r = -0.26, p = 0.007) at visit 1. The change in serum YKL-40 levels between the visits was significantly correlated with changes in FEV(1) (r = -0.28, p = 0.006) and ACT score (r = -0.22, p = 0.037). Patients with elevated YKL-40 levels had significantly greater corticosteroid use than patients with lower levels. CONCLUSIONS: YKL-40 was reduced in the serum of asthmatic patients after appropriate treatment, and the levels correlated with improvements in %FEV(1) and ACT. High levels of serum YKL-40 may be refractory to current asthma treatments. TRIAL REGISTRATION: ChiCTR-OCC-13003316 ELECTRONIC SUPPLEMENTARY MATERIAL: The online version of this article (doi:10.1186/1471-2466-15-1) contains supplementary material, which is available to authorized users.