Figure 2.

Chitinase 3-like-1 (YKL-40/BRP-39) is elevated in humans with asthma sensitized to fungi but protects against AHR in an experimental animal model of fungal asthma. A: bronchoalveolar lavage fluid (BALF) was collected from subjects with atopic asthma who were sensitized (n = 28) or were not sensitized (n = 28; sputum) to fungi. YKL-40 levels were quantified in clarified BALF supernatants by Milliplex. Data were normalized to the total protein content of each sample and expressed as mean pg/mg protein (each symbol represents a single subject). *P value <0.05 (two-tailed Student’s t test). B: Balb/c wild-type (WT) and BRP-39-deficient (Chi3l1^−/−) mice were chronically exposed to A. fumigatus as described in the materials and methods. Twenty-four hours after the last organism challenge, airway (Newtonian) resistance was analyzed via mechanical ventilation using the flexiVent pulmonary function system. Naïve mice served as controls for baseline lung function. The figures illustrate cumulative data from two independent studies (n = 6 mice per group per study). Data are expressed as means ± SE. ***P value  < 0.001 (two-way ANOVA).