Diagnosis of human herpesvirus-7 active infection in transplant patients has proved difficult, because this virus is ubiquitous and can cause persistent infections in the host. The significance of viral DNA detected in leukocytes by PCR is unclear and cross-reaction in serological tests may occur. This study aimed to evaluate nested-PCR to detect human herpesvirus-7 active infection in liver transplant recipients compared to healthy individuals. human herpesvirus-7 nested-PCR was performed on leukocytes and sera of 53 healthy volunteers and sera of 29 liver transplant recipients. In healthy volunteers, human herpesvirus-7 was detected in 28.3% of leukocytes and 0% of serum. human herpesvirus-7 was detected in sera of 48.2% of the liver transplant recipients. Nested-PCR on DNA extracted from leukocytes detected latent infection and the study suggests that nested-PCR performed on serum could be useful to detect human herpesvirus-7 active infection in liver transplant recipients.Key-words: human herpesvirus-7. healthy individuals. Nested-polymerase chain reaction. Liver transplantation. RESUMODiagnóstico da infecção ativa pelo herpesvirus humano-7 é difícil devido ao fato deste vírus ser ubíquo e poder causar infecção persistente no hospedeiro. O significado da detecção do DNA viral por reação em cadeia da polimerase não é claro e, reações cruzadas podem ocorrer em testes sorológicos. O objetivo deste estudo foi avaliar a nested-PCR para detectar infecção ativa pelo herpesvirus-7 em receptores hepáticos comparando com indivíduos sadios. Nested-PCR para herpesvirus-7 foi realizado em leucócitos e soro de 53 voluntários sadios e em soro de 29 receptores hepáticos. Nos voluntários sadios, herpesvirus-7 foi detectado em 28,3% de leucócitos e 0% de soro. herpesvirus-7 foi detectado em soro de 48,2% de receptores hepáticos. Nested-PCR em DNA extraído de leucócitos detectou infecção latente e o estudo sugere que nested-PCR realizada em soro poderia ser útil para detectar infecção ativa por herpesvirus-7 em receptores de fígado.Palavras-chaves: herpesvirus humano-7. Indivíduos sadios. Nested-reação em cadeia da polimerase. Transplante hepático. human herpesvirus-7 (hhV-7) was first isolated by Frenkel et al 5 from activated CD4 + peripheral blood T cells of a healthy individual. It is a member of the betaherpesvirinae subfamily of the Betaherpesviridae (DNA virus). Both, hhV-7 and hhV-6 (human herpesvirus 6) primary infections cause common febrile infectious syndromes of early childhood, known as exanthem subitum and roseola 16 . Investigations conducted in the United States 8 and Mexico 11 presented hhV-7 seroprevalence rates of 65% and 98%, respectively. In Brazil, Freitas et al 4 found a hhV-7 seroprevalence rate of 93.3% in individuals > 10 years of age.Similar to other betaherpesviruses, hhV-7 frequently remains latent in the host and can reactivate during immunosuppression following organ transplantation 9 . The most well-known member of the betaherpesviruses is human cytomegalovirus (hCMV) and it is consider...

Cytomegalovirus (CMV) is one of the most prevalent infectious pathogen in transplant recipients, including those receiving bone marrow or stem cell grafts. Rapid diagnostic tests to identify active CMV infection and preemptive treatment are significant improvements in the management of CMV. Two newly identified beta herpesviruses, human herpesvirus-6 (HHV-6) and human betaherpesvirus-7 (HHV-7), are genetically more closely related to each other than to CMV and have been frequently detected in the blood of allogeneic HSCT. HHV-6 reactivation has been associated with fever, rash, delayed engraftment and encephalitis. Also, HHV-7 has been reported as a cause of severe central nervous system disease and with severe GVHD and sepsis secondary to immune suppression. Nested polymerase chain reaction in blood samples (serum or leukocytes) was used to monitor active CMV, HHV-6 and HHV-7 infections and disease in forty-three HSCT patients for up to 150 days after transplant. All adult recipients with a risk for CMV disease (D+/R+; D+/R-) were enrolled in this study. Acyclovir was used at low doses prior to the transplant as herpes virus prophylactic therapy. Patients who were at least 2 consecutive N-PCR positive for CMV received preemptive therapy with ganciclovir. The prevalence's of positive active CMV, HHV-6 and HHV-7 infections were 72%, 4.6% and 13.9%, respectively. Thirteen patients died (30.2%). Biopsies confirmed CMV disease occurred in 8 out of 43 patients (18.6%), in the gastrointestinal tract. All of them presented active CMV infection and one presented active CMV+HHV-6 infection. None of these patients presented active HHV-7 infection. One patient with CMV disease died by disseminated CMV. Detection of active HHV-6 and HHV-7 infections was low and clinically significant complications were rare. CMV disease remains the most prominent disease associated with HSCT. Results show that surveillance with N-PCR ─ a sensitive, non-invasive and low-cost technique for detection of active beta herpesvirus infections ─ can be used when antigenemia or DNA quantitative methods are unavailable, because patients with a propensity for developing CMV disease can be readily identified and pre-emptive therapy started.

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