Discussion
EVENTS
Our study results showed that compared with kidney transplant recipients who received ATG 6.0 mg/kg as an induction regimen with early steroid withdrawal, those who received ATG 4.5 mg/kg were more likely to show composite outcomes of biopsy-proven acute rejection, The dose of ATG ranged from 5.4 to 10 mg/kg in previous randomized trials that compared ATG with IL-2 receptor antagonist as an induction regimen in kidney transplant recipients [Our results are in line with those of previous reports that the degree of T cell depletion and reconstitution did not significantly differ according to ATG dosage [The following limitations of our study should be addressed. First, this study was ceased earlier than expected due to concerns regarding the observed risks of the composite outcome in the ATG4.5 group; also, the number of enrolled patients was less than the designated sample size. This limitation stands out because the study cohort were low risk live donor transplants in which the targeted events would be predictably low frequency compared to higher immunological risk or deceased donor subjects. Therefore, our results fall short of being able to draw confirmative conclusions. Second, only for-cause biopsies were performed in this study. To exclude subclinical rejection, it would be better if a protocol biopsy was performed. Third, the occurrence of early composite outcomes might have affected the reconstitution of immune cells because physicians often re-used steroids when patients developed the composite outcomes. Fourth, the trough level of tacrolimus and the MMF dose were relatively low which could have contributed to a higher rate of composite outcomes in the ATG4.5 group. Fifth, we could not find significant differences in the proportion of specific immune cells at each time between the groups which may be due to the small number of PBMC samples.In conclusion, we compared ATG 4.5 mg/kg regimen with ATG 6.0 mg/kg as an induction regimen in non-sensitized Asian recipients undergoing kidney transplantation from living donors, and found that ATG 4.5 mg/kg and early corticosteroid withdrawal in association with a low dose maintenance regimen resulted in higher rates of biopsy-proven acute rejection and 