Mycophenolate mofetil tied to increased risk of HHV-6 encephalitis after allogenic transplantation

Japanese investigators found that those who were administered mycophenolate mofetil along with a calcineurin inhibitor developed a much higher rate of infection: 12% in cord blood and 6% in other transplants.

HHV-6 encephalitis is a significant problem in Japan, in part because the use of cord blood transplantation (CBT) is more prevalent. The group retrospectively analyzed 73 patients who were given mycophenolate mofetil (MMF) as prophylaxis for graft-vs host disease.  Viral infection has been found to occur more frequently in patients who have received MMF (Hamad 2015).

A review of HHV-6 encephalitis in CBT and non-CBT found an overall incidence of 8.3% and 0.5% respectively (Scheurer 2012). A recent large scale retrospective analysis in Japan found cumulative incidence of HHV-6 encephalitis to be 2.3% and 5.0% for BMT and CBT respectively.

Another study recently suggested that MMF is a risk factor for HHV-6 encephalitis (Myashita 2017). The authors warn that MMF should be administered with caution and that patients using this therapy be monitored closely for HHV-6 encephalitis.

Other interesting findings:

  • In the subset that received myeloablative conditioning, the rate of encephalitis was even higher: 14.7%.
  • All of the encephalitis patients were male.
  • Two of 7 encephalitis patients developed severe autonomic dysfunction.

Read the full paper: Inui 2018