Abstract： Objective To test plasma levels of uPA,uPAR,D-dimer,IL-6 and TNF-α,and observe the relationships between uPA,uPAR and D-dimer,IL-6,TNF-αin patients with SIRS.Methods A prospective,clinical case-control study was adopted.Cases were collected from our hospital in January 2008 to January 2010,and all were ＞ 55 years of age.Venous blood samples were collected via routine venipuncture.Eighty-five patients were divided into two groups according to diagnostic criteria of SIRS:SIRS group collected from Intensive Care Unit ( n =50) and non SIRS group collected from medical ward ( n =35).The control group comprised 30 unrelated healthy blood donors who visited the General Health Checkup Division at our hospital.Patients with (1) pregnant women; (2) cancer; (3) died after admitted into ICU in 7 days; (4) after cardiopulmonary resuscitation ; ( 5 ) with previous blood system diseases; (6) patients with SIRS before admitted into ICU were excluded from the study.uPA,uPAR,D-D,IL-6 and TNF-α in blood were detected by commercial enzyme-linked immunosorbent assay (ELISA) kits.The data was analyzed using SPSS version17.0.Data accorded with normal distribution of measurement was expressed as mean ± standard,and analyzed by independent-samples t test; non-normal distribution of measurement data,expressed by median,was analyzed with Mann-Whitney test.Relationships between plasma levels of uPA,uPAR and D-dimer,IL-6 TNF-α were analyzed using Spearman rank correlation test.To compare with blood level of uPA,uPAR,IL-6 and TNF-α in SIRS patients in the application of diagnostic value of MODS,we constructed the receiver operating characteristic curve ( ROC curve) for blood levels of uPA,uPAR,IL-6 and TNF-α in 24 h.Results The plasma levels of uPA,uPAR,D-dimer,IL-6 and TNF-αin patients of SIRS were obviously higher compared with non-SIRS and normal controls ( all P ＜ 0.01 ).Correlation analysis showed that there was positive correlation between uPAR level and IL-6 level (r =0.395,P =0.004) ; there was positive correlation between uPAR level and TNF-αlevel ( r =0.606,P ＜0.01 ).There was no correlation between uPAR levd and D-dimer level ( r =- 0.069,P =0.632).There was no correlation between uPA level and D-dimer,IL-6 or TNF-α ( all p ＞ 0.05).There ROC curve were made based on the abilities of uPAR,D-dimer,IL-6 and TNF-αlevels in 24 hours to diagnose MODS,and the ROC areas under the curves were 0.76,0.58,0.86,0.83 respectively.Conclusions These results demonstrate that uPA and uPAR play a major contributory role in patients with SIRS in the process of coagulation disorders,but the mechanism in SIRS is not the same.uPAR may play a central rolein the development of SIRS to MODS.