Risk factors and clinical consequences of human herpesvirus 7 infection in paediatric haematopoietic stem cell transplant recipients

Abstract

Human herpesvirus 7 (HHV-7) is the least studied beta-herpesvirus in transplant settings. This prospective study examined the activity of HHV-7 during the first 12 weeks post-stem cell transplant in 59 paediatric patients. The presence of HHV-7, human cytomegalovirus (HCMV) and human herpesvirus 6 (HHV-6) in blood was monitored weekly by a multiplex nested polymerase chain reaction. Overall, 33 (55.9%) patients had one or more surveillance blood sample(s) positive for HHV-7. In contrast to HCMV and HHV-6, no obvious peak time of reactivation was observed for HHV-7. The occurrence of HHV-7 DNAaemia showed a significant negative association with HHV-6 (P=0.022), but with no association with HCMV. A significant higher positive rate for HHV-7 was found in autologous versus allogeneic (P=0.002), and in peripheral blood versus umbilical cord/marrow (P<0.001) transplant. Acyclovir had no effect, whereas ganciclovir was associated with a lower rate of HHV-7 reactivation (P=0.009). One patient died of HHV-7 associated brain stem encephalitis. The administration of colony stimulating factor, occurrence of acute graft versus host disease, time to neutrophil and platelet engraftment showed no significant association with the occurrence of HHV-7 DNAaemia.

Characterization of the Lymphotropic Amplicons-6 and Tamplicon-7 Vectors Derived from HHV-6 and HHV-7

“…In searching for neurological implementation, viral DNA was detected in cerebrospinal fluid (CSF) by PCR [Savolainen et al, 2005], but severe complications were reported to be rare. There were several reports of the association of viral infection with encephalitis [Caserta, 2004;Chan et al, 2004;Dewhurst, 2004;Rapaport et al, 2002;Yamashita and Morishima, 2005]. However, the causal relation merits further investigation, especially since these patients have a generalized reduced health state.…”

Detection of Human Herpesvirus-7 DNA in Bronchoalveolar Lavage

“…The direct manifestation of HHV-7 reactivation posttransplantation is poorly known [21,22] . Considering the relationship between viral reactivation related with ␤ -herpesviruses occurring after transplantation, several studies have evidenced the development of HCMV disease together with the concomitant reactivation of HHV-7, but its role is uncertain [22][23][24][25] , also taking into consideration the several host-and virus-related factors favoring the development of HCMV disease [26] . In a study on lung transplant recipients, Ross et al [6] evidenced an association between bronchiolitis obliterans (BO) with organizing pneumonia (BOOP) and HHV-7 DNA positivity in all 7 cases found in a group of 19 graft recipients, although viral load was not evaluated.…”

Rare viral infections in children receiving hemopoietic stem cell transplant

“…[14][15][16] Finally, the incidence of respiratory syncytial virus pneumonia has been reported to be 1.5% in adults or adolescents undergoing autologous HSCT. 17 No data in younger children are available.…”

“…14,18 Also, HHV-7 has been reported as a cause of severe central nervous system disease after allogeneic HSCT. 16,19 Moreover, HHV-7 was associated with severe GvHD and sepsis secondary to severe immunosuppression after HSCT from matched unrelated donors. 20 HHV-8 has been associated with the development of visceral Kaposi's sarcoma or lymphomas in immunocompromised patients, [21][22][23] and de Medeiros et al 24 have reported a case of Kaposi's sarcoma after allogeneic HSCT.…”