Abstract: Objective To investigate the expression of vitamine D3 upregulated protein-1 (VDUP1) in peripheral eosinophils at different stagesof asthma and its correlation with clinical manifestations of asthma. Methods Fourteen normal volunteers and 51 mild to moderate asthma patients, including 16 untreated patients with asthma attack and 35 with asthma remission by continuously corticosterone inhalation. The symptom severity and pulmonary function indices were evaluated and induced sputum eosinophil counts and blood eosinophil count measured. VDUP1 and β-actin gene fragments were amplified simultaneously by RT-PCR from the total RNA of peripheral eosinophils, and 10 μl of the RT-PCR product underwent agarose gel electrophoresis and the VDUP1/β-actin ratio was obtained by Gel-Pro software. Results VDUP1/β-actin ratio significantly decreased in untreated patients with asthma attacks in comparison with normal volunteers (0.314±0.242 vs 0.532±0.279) but not in patients with asthma remission (0.612±0.381). In the former patients, a positive correlation of VDUP1/β-actin ratio was found with FEV1.0% (r=0.587, P=0.046) and %PEF (r=0.563, P=0.033), whereas an inverse one observed with sputum eosinophil count (r=-0.436, P=0.049). Conclusion VDUP1 expression in the eosinophils correlates to eosinophil activation and may influence the disease severity of asthma patients.