BK Virus in Renal Transplant Patients Using Alemtuzumab for Induction Immunosuppression

Alemtuzumab, a monoclonal antibody utilized as induction immunosuppression in renal transplant, targets CD52-positive lymphocytes, causing profound B- and T-cell depletion. The administration of such novel, potent immunosuppressive agents, with the goal of reducing rejection, poses an increased threat of BK virus infection in renal transplant recipients.

This internal review boardapproved retrospective analysis included 676 renal transplant patients during a 9-year period. All patients were induced with alemtuzumab, and most received a steroid-minimizing regimen. BK viremia was defined as a clinically significant BK virus infection confirmed by polymerase chain reaction.

Of total study recipients, 58 (8.6%) were positive for BK viremia. African American race/ethnicity, age > 65 years, and rejection showed significant associations with BK viremia. Kaplan-Meier analyses demonstrated significant differences in 3-year (P = .032), 5-year (P = .025), and overall rejection (P = .031) between patients with and without BK viremia. Differences were found in overall (P = .002) and 5-year (P = .001) death-censored graft survival for patients positive for BK viremia plus another non-BK infection versus patients without BK viremia or other infection. BK viremia-positive patients with other infections had significantly lower overall (P = .010) and 5-year (P = .010) death-censored graft survival than patients with BK viremia but without other infections. When we excluded other infections, we observed no differences between BK viremia-positive and BK viremia-negative patients.

BK viremia incidence following alemtuzumab induction therapy appears to be comparable to that shown in other reports and slightly lower than the incidence in patients receiving non-alemtuzumab immunosuppression. BK virus may increase risk of rejection, and BK virus plus another infection may lead to decreased graft survival. African American patients, patients > 65 years old, and patients with rejection history may be at increased risk of BK virus. Closer screening should be considered in these populations.