[The early C4d urinary excretion and long-term kidney graft survival in patients treated with tacrolimus and mycophenolate mophetil].
The C4d urinary excretion seems to increase with the risk of graft rejection or progression of chronic allograft nephropathy although its impact on long-term kidney transplant (KTx) outcomes remains unclear. Presently the most common maintenance immunosuppression schemes (IS) includes corticosteroids and cyclosporine or tacrolimus (Tac) with mycophenolane mophetil (MMF), and Tac combined with MMF is regarded to be superior to other schemes. The aim of the study was to determine whether the initial (1-3 months post KTx) level of C4d urinary excretion may help to predict long-term kidney allograft transplantation outcomes in patients treated with Tac+MMF as maintenance IS.


METHODS
The study involved 66 patients who had undergone kidney allograft transplantation. The urine specimens taken from the morning urine portion was assessed by ELISA test for C4d excretion. To increase the objectivity of the assessment all measurements were divided by urinary creatinine excretion (ng/mgCr). The study population was grouped according the calculated Roc curve (the cut off value of the urinary C4d excretion 13.1 ng/mgCr; AUC 0.93; 95% CI 0.74-0.95) into LC4d and HC4d, C4d below or above 13.1 ng/mgCr.


RESULTS
The mean C4d urinary excretion was 166.6 +/- 186.3 ng/mL (3.9 +/- 6.2 ng/mgCr), in LC4d and HC4d 34.8 +/- 102.2 ng/mL (1.1 +/- 6.4 ng/mgCr) and 347.3 +/- 255.7ng/mL (19.2 +/- 5.9 ng/mgCr), respectively. In accord with the division of study population, the statistically significant differences were seen between LC4d and HC4d in urinary C4d excretion Z = 4.4; p = 0.019 (Z = 4.9, p = 0.011 for excretion calculated per urinary creatinine). Kaplan-Meier curve analysis demonstrated a higher graft survival rate in LC4d than in HC4d group (p = 0.048 by log-rank) in ten years follow-up.


CONCLUSIONS
In patients treated with tacrolimus and mycophenolate mophetil as a maintenance immunosuppression, the lower C4d urinary excretion in the early post-transplant period seems to be a low significance prognostic marker of a better long-term kidney allograft transplantation outcome.
Rafał
R
Zwiech
D000328:Adult; D064591:Allografts; D015415:Biomarkers / Q000652:urine; D015935:Complement C4b / Q000652:urine*; D005260:Female; D006085:Graft Survival / Q000187:drug effects* / Q000502:physiology*; D006801:Humans; D007166:Immunosuppressive Agents / Q000494:pharmacology*; D016030:Kidney Transplantation; D008297:Male; D008875:Middle Aged; D009173:Mycophenolic Acid / Q000031:analogs & derivatives* / Q000494:pharmacology; D010446:Peptide Fragments / Q000652:urine*; D016559:Tacrolimus / Q000494:pharmacology*
D015415:Biomarkers; D007166:Immunosuppressive Agents; D010446:Peptide Fragments; D015935:Complement C4b; C032261:complement C4d; D009173:Mycophenolic Acid; D016559:Tacrolimus