Simulect and HHV-6 in pediatric renal transplantation

Herpes virus reactivation is of increasing interest as we aim to decrease morbidity and mortality in the pediatric renal transplant population. We previously reported increased reactivation of HHV-6 and Epstein Barr virus (EBV) with anti-thymocyte globulin/ALG induction therapy. HHV-6 reactivation and de novo infection has been monitored in 31 consecutive pediatric renal transplant patients receiving antibody induction with Simulect. Human Herpes virus-6 (HHV-6) was correlated with EBV reactivation and de novo infection rates, allograft function at 1 year, donor source and number, and patient age and gender. One HHV-6 de novo infection was associated with an early grade II rejection that was steroid resistant but ATG/ALG responsive. Sixteen of 31 (54.8%) patients had HHV-6 reactivation during the first year and eight patients had a prior reactivation profile before transplant. Thirteen patients (41.9%) were naïve to EBV infection prior to transplant with evidence of primary infection in 11 of 13 patients between 6 weeks and 1 year posttransplant. EBV reactivation was noted in four patients with past immunity to EBV. IgM Ab to EBV or HHV-6 during the first year posttransplant did not correlate with risk of rejection during the first year or graft function one year posttransplant. The only patient with positive HHV-6 IgM Ab in the first posttransplant month was a de novo infection in a 2-year-old boy who was naïve for HHV-6 at the time of transplant. Simulect appears safe in pediatric renal transplant with low risk of HHV-6 or EBV infection in the first 1 to 2 months posttransplant.