Data are presented visually as box plots. Continuous variables are reported as the median value, with the interquartile range in parentheses. Statistical analysis was performed by the nonparametric Mann-Whitney U test for unpaired samples to compare data in healthy controls and transplant recipients, and diabetic vs non-diabetic transplant recipients. A linear regression model was constructed to identify potential explanatory variables for urinary ACE2 and ACE levels in the 100 transplant subjects. The dependent variable was the measure under study (e.g. ACE2 activity) while the following explanatory variables were entered into the model: age, gender, diabetes, eGFR, albuminuria, hypertension, and use of calcineurin inhibitors. Variables were forced in simultaneously and removed from the model if not statistically significant. Standardized regression coefficients (b) are presented for each dependent variable in the model. Data were analyzed using SigmaStat (version 3.01 A; SYSTAT) and JMP (version 8.0.1, SAS Inc.). For all data, a p value ,0.05 was considered significant.