Abstract: ObjectiveTo Explore the change of IL-4 and IL-18 levels in serum of recipients transplanted with allogeneic hematopoietic stem cells and its relationship with acute graft versus host disease (aGVHD) and to provide reliable cytokines for the diagnosis of aGVHD. Methods ELISA(double sandwich enzyme-linked immunosorbent assay) was used to detect serum level of IL-4 and IL-18.Twenty patients underwent allo-HSCT(experimental group) and 16 underwent auto-HSCT (control group) were enrolled in this study.Samples were collected on 14 days,1day before hemapoietic stem cell infusion,then every week until the 8 weeks after transplantation.In patients with aGVHD,Samples were taken twice a week. Results The IL-4 and IL-18 levels in serum demonstrated no significant difference between 14 day and 1 day before stern cell infusion or 1 day before infusion and 7day after infusion in both experimental and control groups(P>0.05).aGVHD was happened in six patients of experimental group,including 3 aGVHD Ⅰ～Ⅱs,3 aGVHD Ⅲ～Ⅳs; The serum level of IL-4 and IL-18 demonstrated no significant difference before and after transplantation in the non-aGVHD patients in experimental group.The aGVHD patients in experimental group demonstrated aGVHD clinical symptom between 16 day to 52 day after transplantation,the time of serum IL-4 and IL-18 level changed was earlier than that of clinical symptom.The diagnosed IL-4 and IL-18 levels in serum demonstrated a significant decrease and increase compared with that of the 7day levels for those patients respectively(P<0.05);while the indicators also demonstrated a significant increase and decrease after anti-aGVHD treatment relief (P<0.05) ; the time of interval of first IL-4 decrease in serum was 11 day to 43 day after transplahtation for aGVHD patients in the experimental group,significantly lower than that of those in the control groups(P<0.05).The time of interval of first IL-18 increase in serum was 11 day to 47 day after transplantation for aGVHD patients in the experimental group,significantly higher than that of those in the control groups(P<0.05). Conclusion It suggests that there is a relationship between serum level of IL-4 and IL-18 and the presentation of aGVHD.The detection of serum IL-4 and IL-18 is helpful to the prediction and early diagnosis of aGVHD.