Introduction: The occurrence of CMV infection/disease after renal transplantation depends, among other factors, on the pre-transplant serological status of the recipients. Among CMV IgG-positive individuals, immunosuppression regimens containing mTOR inhibitors confer protection against the development of this complication. Little is known about these effects among patients previously seronegative.
Objectives: To analyze the occurrence of CMV events across different regimens of immunosuppression containing a calcineurin inhibitor.
Methods: Dual-center, retrospective study including single kidney transplant recipients (recipient-negative/donor-positive IgG-CMV serology) >18 years-old. There were no pharmacological prophylaxis against CMV; preemptive therapy was performed instead. The patients were followed until 1-year after transplantation, graft loss or death, whichever occurred first.
Results: Between August 8, 2014 and December 31, 2015, 89 subjects were included for analysis. There were 75% of males, median age of 48 years, 16% diabetics, median cPRA 0%, 76% deceased donors, median cold ischemia time of 23 hours. All recipients received thymoglobulin induction (dose of 3 - 4.5 mg/kg). From these, 30 patients received tacrolimus (TAC) and azathioprine (AZA), 24 patients received TAC and mycophenolate, and 35 patients received TAC and everolimus (EVR). The groups differed on the proportion of expanded criteria donors (0% vs. 50% vs. 9%, p=0.007) and steroid maintenance (100% vs. 79% vs. 31%, p<0.001).
There were similar rates of biopsy-proven acute rejection in the first year (10% vs. 8% vs. 6%, p=0.811). There were no significant differences in the occurrence of first CMV event (73% vs. 84% vs. 74%, p=0.643), in the severity of the episodes (CMV disease in 35% vs. 40% vs. 37%, p=0.536), in the rate of recurrence (57% vs. 79% vs. 48%, p=0.058), or in the median duration of treatment (19 vs. 25 vs. 23 days, p=0.328). Among patients treated with TAC-AZA, The median time from transplantation to the first CMV event was longer in the TAC-EVR group (31 vs. 31 vs. 46 days, p<0.001). At 1-year, there were similar rates of graft survival (97% vs. 92% vs. 94%, p=0.730) and renal function (MDRD estimated glomerular filtration rates of 53.6 vs. 60.3 vs. 55.4 ml/min, p=0.549). There were no deaths.
Conclusion: Among CMV-negative kidney transplant recipients, in the absence of pharmacological prophylaxis, there was no impact of the choice of CNI-containing immunosuppressive regimen on the occurrence and severity of CMV events in the first year after transplantation.