Fig. 4

Urine proteinase-3 activity over time in kidney transplant patients with serial histology. Four kidney transplant patients had serial protocol (surveillance) biopsies at pre-specified times post-transplant or as clinically indicated. Urine samples taken at these time points were evaluated for PR3/PRTN3 activity. a–d Serial protocol biopsies demonstrated a trend towards low urine proteinase-3 activity with stable transplants (black square, normal histology and stable graft function, Banff i0t0) and clinical T-cell mediated rejection Banff ≥ 1A (black-up pointing triangle, clinical Banff ≥ 1A rejection, Banff i2–3 t2–3). Elevated urine PR3/PRTN3 activity was detected in a significant proportion of samples from kidneys with low grade subclinical inflammation ( , borderline subclinical inflammation, Banff i0–1 t1–2)