Abstract: Objective To investigate the expression of Slingshot-1L(SSH-1L)in peripheral blood eosinophils of asthmatic patients.Methods Peripheral vein blood sample of 30 ml was collected from 15 healthy volunteers,15 asthmatic patients with glucocorticoid treatment and 15 asthmatic patients without the treatment.The eosinophils were isolated,purified and counted for each sample,and SSH-1L/β-actin gene fragments were amplified simultaneously by RT-PCR for the total RNA.SSH-1L protein was detected by Western blotting from the total protein of the peripheral eosinophils.The expressions of SSH-1L at both mRNA and protein levels are compared between different groups.Results SSH-1L/β-actin ratio significantly increased in untreated patients with asthma attacks in comparison with healthy volunteers(P<0.05),which did not occur in patients treated with glucocorticoids(P>0.05).The optical density of SSH-1L protein significantly increased in untreated asthmatic patients(P<0.05),but not in patients treated with glucocorticoids(P>0.05),as compared with the healthy volunteers.Conclusion Significantly increased SSH-1L expression in peripheral eosinophils may play an important role in the activation and migration of eosinophils.