MP788
PREDICTORS OF TRANSPLANT FAILURE IN PATIENTS UNDERGOING INDICATION RENAL BIOPSY

INTRODUCTION AND AIMS: This study considers indication renal transplant biopsies and factors which may be important predictors of transplant loss and patient death. We sought to identify the time line of histological diagnosis, from transplant, in our population and to identify predictors of graft and patient survival in those undergoing indication renal transplant biopsy.

METHODS: All indication renal transplant biopsies undertaken between 01/2011 and 12/2015 were identified. Demographic data including immunological and outcome data was recorded. Statistical analysis was undertaken in SPSS (v22).

RESULTS: 354 patients underwent 549 biopsies. Mean patient and transplant age at time of biopsy was 43.2 ±15.3 and 4.2±5.8 years respectively. 44.9% (n=247) of biopsies showed evidence of Cell mediated rejection (CMR)/ABMR or both. 9.3% (n=51) demonstrated features of chronic transplant glomerulopathy (CTG). DSA was present at the time of biopsy in 23.1% (n=127). In transplants aged < 6 months old histological diagnosis was CMR in 32.5% (n=69) with ABMR seen in 2.8% (n=6). In transplants aged ≥10 years, CTG was seen in 32.5% (n=26) with ABMR accounting for 6.3% (n=5). 22.9% (n= 81) of transplants failed at a median of 182 days from most recent biopsy. On cox regression analysis, peritubular capillary (PTC) C4d and CTG were independent predictors of transplant failure. Probability of transplant failure was 45% and 50% at one year if mixed rejection or CTG were present. 9.3% (n=33) patients died at a median of 227 days from most recent biopsy. Independent predictors of death included deceased donor transplant, patient age and presence of ABMR on biopsy (p<0.05).

CONCLUSIONS: Acute ABMR is a risk factor for patient loss whilst chronic ABMR is a risk factor for transplant loss. This association is independent of DSA but dependent upon PTC C4d staining, indicative of donor humoral activity - HLA or otherwise. Histological diagnosis in an indication transplant biopsy is an important factor in predicting outcome. This study is limited by the inherent bias in patient selection with indication biopsy