Conversion from mycophenolate mofetil to mizoribine in the early stages of BK polyomavirus infection could improve kidney allograft prognosis: a single-center study from China.

BACKGROUND

Some studies have suggested mizoribine (MZR) could inhibit the replication of BK polyomavirus (BKPyV). The purpose of this study was to explore whether conversion from mycophenolate mofetil (MMF) to MZR in the early stages of BKPyV infection can improve kidney allograft prognosis.

METHODS

Twenty-one kidney transplant recipients with BKPyV viruria/viremia and ten with BK polyomavirus-associated allograft nephropathy (BKPyVAN) received MZR conversion therapy were retrospectively identified. The clearance rate of urine and blood BKPyV DNA, change of serum creatinine (SCr), uric acid (UA), hemoglobin (HB), white blood cell (WBC), lymphocyte ratio, platelet (PLT), routine urinalysis, panel reactive antibody (PRA), and gastrointestinal disorders during follow-up of the 2 groups were evaluated and compared.

RESULTS

After MZR conversion therapy, the clearance rate of urine and blood viral load in BKPyV viruria/viremia group were 85.7 and 100 %, while that in BKPyVAN were 40 and 87.5 %, respectively. Stable SCr were observed in all cases of BKPyV viruria/viremia group, while that of BKPyVAN was only 40 % (P < 0.001) and one even progressed to end-stage renal disease. The results of routine urinalysis in the two groups showed no significant changes before and after MZR conversion therapy. However, in BKPyV viruria/viremia group, four cases developed acute rejection and one had positive PRA-II but no donor specific antibody, requiring conversion back to MMF. Hyperuricemia was the common adverse effect of MZR.

CONCLUSIONS

Conversion from MMF to MZR could help clear BKPyV infection. As compared to BKPyVAN, patients who underwent initiation of MZR conversion therapy in the early stages of BKPyV infection maintained stable allograft function. Prospective studies with larger sample size are needed to ascertain this preliminary finding.