AIM: To examine whether Akt signal pathway proteins, including Akt, NF-?B and I?B?, are activated in kidney tissue of murine chronic graft-versus -host disease (GvHD) lupus nephritis in vivo , and whether prednisone suppres ses activation of them. METHODS: Akt activity and phosphorylated I?B? were detected by Weste rn-blot. Activation of NF-?B was detected by electropheretic mobilit y shift assay (EMSA). RESULTS: Activity of Akt, NF-?B and phosp horylated I?B ? were significantly increased in kidney tissue of murine chronic graft-versus -ho st disease (GvHD) in 8th week and 12th week after monocell injection, respective ly. However, they were no significant elevation in 16th week, when compared with controls. Prednisone treatment significantly prevented the increase in serum an ti-dsDNA antibody level, urinary protein excretion and glomerular cell prolif eration in GvHD mice, indicating the beneficial effects of prednisone on t his model. Prednisone also significantly suppressed the increase in the activities o f glomerular Akt, NF-?B and phosphorylated I?B?. CONCLUSION: T his study provides t he first evidence of marked increase in glomerular Akt-NF-?B signal pathway act ivities in murine chronic graft-versus-host disease lupus nephritis. The benefic ial effect of prednisone on this lupus nephritis model may be partially mediated by the suppression of abnormal Akt- NF-?B activation.