#5811 URINARY CXCL9 AND CXCL10 CONCENTRATIONS AND KIDNEY TRANSPLANT INJURY

Abstract

Abstract Background and Aims Kidney transplant rejection is diagnosed by the kidney biopsy which is an invasive diagnostic method, however, non-invasive biomarkers, distinguishing normal kidney transplant from transplant rejection would be prefered but are lacking. CXC chemokine ligand 9 (CXCL9) and CXC chemokine ligand 10 (CXCL10) are gamma interferon inducible small cytokines. The aim of this study was to evaluate urinary CXCL9 and CXCL10 as potential biomarkers of allograft rejection. Method 117 kidney transplant recipients undergoing kidney transplant biopsy (surveillance or indication) were included into this study. Spot urine samples were collected before kidney biopsy for urinary creatinine, CXCL9 and CXCL10 measurement. The ratios of CXCL9 over urinary creatinine and CXCL10 over urinary creatinine were calculated. Kidney biopsies were analyzed according to Banff criteria by an experienced pathologist. Results 26 (22.2%) of kidney biopsies were defined as normal histology, 24 (20.5%) – antibody mediated rejection, 9 (7.7%) – T cell mediated rejection, 10 (8.6%) mixed rejection, 5 (4.3%) BK virus nephopathy and 43 (36.8%) were defined as other histological lesions. Average CXCL9/creatinine was 0.39 ng/mmol in normal histology group and 12.1 ng/mmol in allograft rejection groups (p<0.01). Average CXCL10/creatinine was 0.26 ng/mmol in normal histology and 4.55 ng/mmol in allograft rejection group (p<0.01). CXCL9/creatinine and CXCL10 moderately correlated to proteinuria at the time of kidney biopsy (accordingly r = 0.595, p<0.01 and r = 0.408, p<0.01). ROC curve for CXCL9/creatinine detecting antibody mediated rejection was 0.79, CI 0.67 to 0.90, p<0.01. ROC curve for CXCL10/creatinine detecting antibody mediated rejection was 0.79, CI 0.64 to 0.94, p<0.01. Conclusion Urinary biomarkers CXCL9/creatinine and CXCL10/creatinine has a potential to distinguish normal renal histology from allograft rejection and correlates to proteinuria at the time of the biopsy.