Elevated expression levels of ANXA1 integrins beta 3 and alpha 3, and TNF- alpha contribute to a candidate proteomic signature in urine for kidney allograft rejection

Purpose: Kidney transplantation is the treatment of choice for end stage renal disease, with long-term allograft loss being the major obstacle, and for which potential treatments are based on a histological diagnosis. The problem is that markers for predicting graft rejection are limited in number, are invasive, and are quite non-specific. We have hypothesized that protein biomarkers might be discovered in the urine of patients when acute or chronic rejection might be occurring. Experimental design: We have established a workflow in which initial screening for candidate biomarkers is first performed using urine samples on large-scale antibody microarrays. This approach generated several dozen candidates. The next step is to qualify some of the strongest signals using the high-throughput Reverse Capture Protein Microarray platform. Results: Four top candidates including ANXA11 Integrin beta and TNF- alpha , initially identified by the antibody microarray platform, were all qualified using Reveres Capture Protein Micriarrays. We also used operating condition (ROC) curves to independently quantify the specificity and sensitivity of these four analytes. Conclusions and clinical relevance: The present data suggest that these novel four analytes in the urine, together or independently, may contribute to a robust and quantitative urine proteomic signature for diagnosing acute or chronic rejection of renal allografts.