Previous studies have demonstrated that HHV-6 infection is associated with acute graft rejection among renal transplant recipients (Caiola 2012). However, a new study from UNIFESP in Brazil indicates that active HHV-6 infection may play a role in patients with renal failure prior to transplantation as well.
The group prospectively monitored HHV-6 infection in 30 kidney transplant patients, collecting samples from recipients and donors prior to transplantation, on a weekly basis for the first two months after transplantation, and every two weeks for an additional two months. Prior to transplantation, active HHV-6 replication was detected in 25% of recipients and in none of the donors. Risk factors for post-transplant active HHV-6 infection included receiving an organ from a living donor (P=.028), recipients IgM+ before transplantation (P=.005), and pretransplantation recipient HHV-6 viral load >10,000 copies/mL of plasma (P=.034).
Although the authors did not discuss the possibility of chromosomal integration, plasma levels of >10,000 HHV-6 copies are consistent with chromosomally integrated HHV-6 (ciHHV-6). It is quite possible therefore, that at least some of the patients with persistent high levels of HHV-6 in the plasma represent patients with the condition. Additional testing would be necessary to confirm these suspicions, as outlined by Pellet et al (Pellett 2011).