Background: It has been revealed sCD30 and sCD26 were correlated with some autoimmune diseases, especially in evaluating the activity of disease. However, little research has been done on primary immune thrombocytopenia（ITP） in this area.Objectives: Our study aimed to investigate the association between sCD30 or sCD26 and ITP, and evaluate their value in ITP.Methods: This study enrolled 47 patients with ITP and 20 healthy persons. The mRNA expression of CD30 was quantified by RT-PCR. Concentrations of sCD30 and sCD26 were measured by ELISA.Results: The concentration of sCD30 was higher in active ITP patients（median, 35.82 ng/ml） than in patients in remission（median, 23.12 ng/ml; P=0.021） and healthy controls（median, 25.11 ng/ml; P=0.002）. Plasma sCD26 levels were decreased in patients in remission compared with controls（median, 599.4 ng/ml vs. 964.23 ng/ml; P=0.004）. No difference was found in sCD26 levels between active ITP patients and controls（P=0.072） as well as between patients in remission and active ITP patients（P=0.237）. Ratios of sCD26/sCD30 in active ITP patients were decreased compared with controls（P=0.005）, while no difference between ITP patients in remission and controls as well as active ITP patients（P=0.198, 0.093, respectively）. By analyzing the relevance of sCD30, sCD26 and sCD26/sCD30 ratio to platelet counts, disease courses and bleeding in active ITP patients, no other relation was found except concentrations of sCD30 were positively correlated with hemorrhage（r=0.493, P=0.017）.Conclusion: Levels of sCD30 and sCD26/sCD30 ratios may contribute to diagnose of ITP and evaluate the activity of disease while sCD26 could not.