Type 6 human herpes virus (HHV6) infection in a group of Brazilian renal transplant recipients

Abstract

Purpose: HHV6 infections are common in humans. However, the frequency and its association with post-transplant complication remains controversial. In recent years, viral infections have an increasing importance as a post-transplant complication, especially after the development of more potent immunosuppressant drugs. The aim of this study was to identify the prevalence of HHV6 and its complications in stable renal transplant recipients. Methods: HHV6 PCR was performed in 71 blood samples obtained from renal transplant recipients in an average 12 months after transplant, comparing them to a control group of 112 healthy blood donors from the same geographic area. Results: Prevalence of positive HHV6 PCR was significantly higher in the transplant population (36% vs.11%, p<0.05). In order to identify risk factors for HHV6 infection and its complications, the transplant recipients were divided in 2 groups, according to the viral PCR status. No differences in demographic parameters, serological status for Hepatitis B, C or Cytomegalovirus, immunosuppressant regimen or induction therapy was observed between groups. However, HHV6 positive patients presented higher incidence of leukopenia, increased aminotransferase, symptomatic or invasive Cytomegalovirus infection and associated viral infections, such as Herpes or Polyomavirus. Despite the lower incidence of acute rejection episodes, the glomerular filtration rate was reduced in the HHV6 positive group after two years of follow-up. Conclusion: In summary, HHV6 was more frequent in renal transplant patients than in the normal controls. HHV6 infection was associated to a higher incidence of symptomatic or systemic Cytomegalovirus and other viral infections, and reduced graft function.