Electron Spin Resonance Spectroscopy of Albumin Transport Quality Is a New Test for Diagnosis of Kidney Transplant Acute Rejection.

Abstract

Background: We looked at the albumin functional disorders caused by proteins released by kidney allograft at the time of acute rejection (AR). Using electron spin resonance (ESR) spectroscopy as a quick and non-invasive technique to measure changes of serum albumin functionality and evaluate utility of the method for monitoring kidney transplant function to detect kidney transplant AR. Methods: We used an ESR spectrometer and 16-doxyl stearic acid as spin label to measure detoxifying activity of albumin (DTE, %) in blood samples from the 91 (44 males and 47 females) kidney transplant recipients. 30/91 had the kidney transplant AR: 9 males and 21 females with median age 39(23; 64) years. Median time on dialysis was 63 (9; 168) months. Donor age was 45.5(20; 61) years. AR was confirmed by kidney biopsy in most cases (24/30), or diagnosed clinically (6/30). Regarding the Banff classification we found the following grades of AR: borderline -4/24, 1A - 4/24, 1B - 6/24, 2A - 7/24, 2B-4/24. Control group included 61 pts without AR: 35 males and 26 females with median age 40(21; 65) years. Median dialysis duration was 28 (4; 168) months and median donor age was 42 (10; 58) years. Results: The diagnostic sensitivity and specificity of this test were 80.0% and 82.5%, respectively, for differentiating non-rejection pts from pts with AR. Cut-off value of DTE was 60%. ROC-analysis showed AUC of 0.880. The median value of DTE was found as 45.95% (29.5%; 58.2%) for pts with acute rejection versus 91% (65.9%; 144.4%) for pts without AR (p< 0,0001). Conclusion: ESR spectroscopy of serum albumin functionality is a sensitive and noninvasive method of detecting kidney transplant AR. It is a useful non-invasive monitoring the postoperative course to detect early AR.