The characteristics of the 50 healthy controls and 100 transplant subjects are depicted in Table 1 . The median age for control subjects was 45 [interquartile range (IQR), 36-50] yrs, and 26% were male. The median age for transplant subjects was 54 (IQR, 42-62) yrs, 65% were male, 38% had diabetes, and 88% had hypertension. Urinary ACE2 Activity, Protein, and mRNA As shown in Figure 1A , urinary ACE2 activity was significantly increased in transplant patients, compared to control subjects [control; median: 1.90 (IQR, 1.04-2.70) ng-eq/mg Cr610 2 vs transplants; median: 3.65 (IQR, 1.13-9.35) ng-eq/mg Cr610 2 ; p = 0.003]. Similarly urinary ACE2 protein by ELISA was significantly increased in transplant patients, compared to controls ( Figure 1B ) [control; median: 1.41 (IQR, 0.00-4.49) ng/mg Cr vs transplants; median: 8.04 (IQR, 0.00-21.11) ng/mg Cr; p,0.001]. In 96% of unconcentrated urine samples from control and 94% from transplant subjects, ACE2 was identified by western analysis as a protein doublet of 120 kDa and 90 kDa. As with urinary ACE2 activity and ELISA measurements, western analyses revealed a significant increase in urinary ACE2 protein in transplant patients compared to controls ( Figure 1C : p = 0.001).