Background:Our study aimed to investigate whether serum total IgE and blood eosinophils,were associated with radiological features of bronchiectasis in a Chinese cohort.

Methods:We retrospectively enrolled bronchiectasis patients who visited Peking University Third Hospital from Jan 1^st,2012 to Oct 7^th,2021.The clinical,laboratory and chest CT characteristics were analyzed in association with serum total IgE level and blood eosinophil count.

Results:A total of 125 bronchiectasis patients were enrolled.The median serum total IgE level and blood eosinophil count were 47.7KU/Land 140cells/µl, respectively.In patients with a higher than normal total IgE (43.2%,n=54), more lobes were involved (p=0.008), and mucus plugs were more common (25.9%vs9.9%, p=0.017) on HRCT, as compared to those with a normal level of total IgE.The higher IgE group was more likely to have bilateral involvement (p=0.059),and had numerically higher Smith and Bhalla scores,but the differences were not statistically significant. In patients with an eosinophil count?150cells/µl (49.6%,n=62), the number of lobes involved was greater (p=0.015),and the Smith and Bhalla scores were higher (9(5,12)vs6(3,9),p=0.009,7(5,11)vs5(3,9),p=0.036).The Smith score was correlated positively with the eosinophil count(r=0.207,p=0.020).Fractional exhaled nitric oxide was correlated with total IgE(r=0.404,p=0.001)and eosinophil count(r=0.310,p=0.014).

Conclusions:Our study demonstrated that serum total IgE and the blood eosinophil count were associated with the radiological extent and severity of bronchiectasis,necessitating further investigation on the role of T2 inflammation in structural abnormalities of this heterogeneous disease.