Kojiro Otsuka1, Hisako Matsumoto1, Akio Niimi1, Shigeo Muro1, Isao Ito1, Tomoshi Takeda1, Kunihiko Terada1, Masafumi Yamaguchi1, Hirofumi Matsuoka1, Makiko Jinnai1, Tsuyoshi Oguma1, Hitoshi Nakaji1, Hideki Inoue1, Tomoko Tajiri1, Toshiyuki Iwata1, Kazuo Chin1, Michiaki Mishima1
1Department of Respiratory Medicine, Kyoto University Graduate School of Medicine, Kyoto, Japan
Tóm tắt
<b><i>Background:</i></b> Recent evidence suggests that YKL-40, also called chitinase-3-like-1 protein, is involved in the pathogenesis of asthma and chronic obstructive pulmonary disease (COPD). Details of sputum YKL-40 in asthma and COPD, however, remain unknown. <b><i>Objectives:</i></b> To clarify associations of sputum YKL-40 levels with clinical indices in asthma and COPD. <b><i>Methods:</i></b> Thirty-nine patients with asthma, 14 age-matched never-smokers as controls, 45 patients with COPD, and 7 age-matched smokers as controls were recuited for this study. Sputum YKL-40 levels were measured and YKL-40 expression in sputum cells was evaluated by immunocytochemistry. <b><i>Results:</i></b> Sputum YKL-40 levels were higher in patients with COPD (346 ± 325 ng/ml) than in their smoker controls (125 ± 122 ng/ml; p < 0.05), but were not significantly different between patients with asthma (117 ± 170 ng/ml) and their controls (94 ± 44 ng/ml; p = 0.15). In patients with asthma only, sputum YKL-40 levels were positively correlated with disease severity (r = 0.34, p = 0.034) and negatively correlated with pre- and postbronchodilator %FEV<sub>1</sub> (r = –0.47 and –0.42, respectively; p < 0.01) and forced mid-expiratory flow (r = –0.48 and –0.46, respectively, p < 0.01). Sputum YKL-40 levels were positively correlated with sputum neutrophil counts in asthma (r = 0.55, p < 0.001) and with neutrophil and macrophage counts in COPD (r = 0.45 and 0.65, respectively, p < 0.01). YKL-40 was expressed in the cytoplasm of sputum neutrophils and macrophages in all groups. <b><i>Conclusions:</i></b> Elevated sputum YKL-40 reflects airflow obstruction in asthma whereas the roles of YKL-40 in the proximal airways in COPD remain to be elucidated.
