Objective:To evaluate the efficacy and mechanism of plasma exchange (PE) in the treatment of severe hepatitis.Methods:139 patients with severe hepatitis were divided into treated and control groups.Both groups were treated with the same routine therapies

but the treated group received the PE.The liver function and serum ammonia

concentration of serum HBV-DNA spectrum were detected before and after treatment with PE.The efficacy and safety were evaluated with clinical parameters respectively.Results:Liver function was significantly improved after PE therapy.There was significant decrease in concentration of serum ammonia from 127.91±57.33 (ixnol/L) to 81.51±40.20 (μmol/L) P <0.001

concentration of serum HBV-DNA(Log10copy/ml) from 5.72±1.39 to 4.13±1.35( P <0.005).Compared with the control group

there was significantly increased cure and improved rate in the treated group [67.03(61/91) vs 50.0 %(24/48)]( P <0.05).The response rates of severe hepatitis in early stage

middle stage were 95 %(19/20) vs 72.27%(8/11) ( P <0.05) and 82.50 %(32/39) vs 57.14 %(12/21) respectively ( P <0.05).Conclusion:PE treatment of severe hepatitis is effective

especially in early and middle stages.