Tacrolimus and mycophenolate regimen and subclinical tubulo-interstitial inflammation in low immunological risk renal transplants

The aim was to evaluate the relationship between maintenance immunosuppression, subclinical tubulo-interstital inflammation and interstitial fibrosis/tubular atrophy (IF/TA) in surveillance biopsies performed in low immunological risk renal transplants at two transplant centers. The Barcelona cohort consisted of 109 early and 66 late biopsies in patients receiving high tacrolimus (TAC-C0 target at 1-year 6-10 ng/mL) and reduced MMF dose (500 mg bid at 1-year). The Oslo cohort consisted of 262 early and 237 late biopsies performed in patients treated with low TAC-C0 (target 3-7 ng/mL) and standard MMF dose (750 mg bid). Subclinical inflammation, adjusted for confounders, was associated with low TAC-C0 in the early (OR: 0.75, 95%CI: 0.61-0.92; p=0.006) and late biopsies (OR: 0.69, 95%CI: 0.50-0.95; p=0.023) from Barcelona. In the Oslo cohort, it was associated with low MMF in early biopsies (OR: 0.90, 95%CI: 0.83-0.98; p=0.0101) and with low TAC-C0 in late biopsies (OR: 0.77, 95%CI: 0.61-0.97; p=0.0286). MMF dose was significantly reduced in Oslo between early and late biopsies. IF/TA was not associated with TAC-C0 or MMF dose in the multivariate analysis. Our data suggest that in TAC and MMF based regimens, TAC-C0 levels are associated with subclinical inflammation in patients receiving reduced MMF dose. This research has been accepted and published in Transplant International. © 2017 Wiley