BACKGROUND: Some studies in vitro have reported that there are CD30 positive T cells in immunological response of allogenic transplantation.OBJECTIVE: To detect the relationship between the level of serum CD30 (sCD30) and clinical rejection in the patients with or without kidney transplantation, and analyze the importance of sCD30 in the estimation of immune state, monitor of acute rejection, and judgment of prognosis. DESIGN, TIME AND SETTING: Clinical case analysis study was performed at Jiangsu People's Hospital between April 2004 and March 2007. PARTICIPANTS: 153 kidney transplantation cases comprising 103 males and 50 females, averagely aged 37 years. METHODS: 3 mL peripheral blood was obtained from recipients before transplantation (without immunosuppressive agent) and at 0, 1, 3, 5, 7, 14, 21, and 28 days. Serum was isolated from obtained blood and placed at -20 ℃. Soluble CD30 levels were detected using CD30 cytokine ELISA kit supplied by BenderMedSystems. MAIN OUTCOME MEASURE: The relation between the soluble CD30 levels and rejection prior to and following transplantation.RESULTS: There was a significant relation in the sCD30 level between the patients with (n=17) and without acute rejection (n=136). The CD30 levels were 113.2 U/mL in the rejection group and 83.2 U/mL in the non-injection group (P < 0.01). No significant difference was determined between both groups in 5 days following surgery (P > 0.05). Significant difference were detected between both groups from 5 days following surgery (P < 0.01). There was no relation between the soluble CD30 level and the time of rejection and release after kidney transplantation (P > 0.05). Receiver operating characteristic (ROC) curve demonstrated that soluble CD30 levels on day 5 post-transplantation could predict acute rejection (area under ROC curve: 0.850). Meanwhile, 100 U/mL was the optimal operational cut-off level to predict rejection (specificity: 85.0%; sensitivity: 83.6%). The patients with positive of soluble CD30 level showed a lower survival rate than those with negative CD30 level (P < 0.01). CONCLUSION: The soluble CD30 levels contributed to predictive the acute rejection and prognosis of kidney transplantation.