The major finding of this study is that urinary ACE2 activity and ACE2 protein are increased in kidney transplant recipients, compared to healthy control subjects, and the presence of diabetes strongly associates with urinary ACE2 levels in the patient population, by multivariate analysis. Female gender associates significantly with urinary ACE2 mRNA and ACE mRNA levels, which are detected in 45% and 65% of transplant recipients, respectively.