The impact of early and late acute rejection on graft survival in renal transplantation.
BACKGROUND
Advances in immunosuppression after kidney transplantation have decreased the influence of early acute rejection (EAR) on graft survival. Several studies have suggested that late acute rejection (LAR) has a poorer effect on long-term graft survival than EAR. We investigated whether the timing of acute rejection (AR) influences graft survival, and analyzed the risk factors for EAR and LAR.


METHODS
We performed a retrospective cohort study involving 709 patients who underwent kidney transplantation between 2000 and 2009 at the Samsung Medical Center, Seoul, Korea. Patients were divided into three groups: no AR, EAR, and LAR. EAR and LAR were defined as rejection before 1 year and after 1 year, respectively. Differences in graft survival between the three groups and risk factors of graft failure were analyzed.


RESULTS
Of the 709 patients, 198 (30%) had biopsy-proven AR [EAR=152 patients (77%); LAR=46 patients (23%)]. A total of 65 transplants were lost. The 5-year graft survival rates were 97%, 89%, and 85% for patients with no AR, EAR, and LAR, respectively. These differences were significant (P<0.001 for both by log-rank test). In time-dependent Cox regression analysis, EAR (hazards ratio, 3.37; 95% confidence interval, 1.90-5.99) and LAR (hazards ratio, 5.32; 95% confidence interval, 2.65-10.69) were significantly related to graft failure. When we set LAR as standard and compared it with EAR, there was no statistical difference between EAR and LAR (P=0.21).


CONCLUSIONS
AR, regardless of its timing, significantly worsened graft survival. Treatments to reduce the incidence of AR and improve prognosis are needed.
Nephrology Division, Department of Medicine, Samsung Medical Center, Sungkyunkwan University School of Medicine, Seoul, Korea.
Eun Hee
EH
Koo
Nephrology Division, Department of Medicine, Samsung Medical Center, Sungkyunkwan University School of Medicine, Seoul, Korea.
Hye Ryoun
HR
Jang
Nephrology Division, Department of Medicine, Samsung Medical Center, Sungkyunkwan University School of Medicine, Seoul, Korea.
Jung Eun
JE
Lee
Department of Surgery, Samsung Medical Center, Sungkyunkwan University School of Medicine, Seoul, Korea.
Jae Berm
JB
Park
Department of Surgery, Samsung Medical Center, Sungkyunkwan University School of Medicine, Seoul, Korea.
Sung-Joo
SJ
Kim
Nephrology Division, Department of Medicine, Samsung Medical Center, Sungkyunkwan University School of Medicine, Seoul, Korea.
Dae Joong
DJ
Kim
Nephrology Division, Department of Medicine, Samsung Medical Center, Sungkyunkwan University School of Medicine, Seoul, Korea.
Yoon-Goo
YG
Kim
Nephrology Division, Department of Medicine, Samsung Medical Center, Sungkyunkwan University School of Medicine, Seoul, Korea.
Ha Young
HY
Oh
Nephrology Division, Department of Medicine, Samsung Medical Center, Sungkyunkwan University School of Medicine, Seoul, Korea.
Wooseong
W
Huh
Acute rejection; Graft survival; Kidney transplantation