Infecção pelo herpesvírus humano 6 (HHV-6) após transplante renal: aspectos clínicos e epidemiológicos e utilização de PCR como método diagnóstico

• Ano de defesa: 2010
• Autor(a) principal: Luiz, Claudia Romani [UNIFESP]
• Tipo de documento: Dissertação
• Tipo de acesso: Acesso aberto
• Idioma: por
• Instituição de defesa: Universidade Federal de São Paulo (UNIFESP)
• Palavras-chave em Português: Evolução clinica; Infecções por citomegalovírus; Reação em cadeia da polimerase/métodos; Transplante renal; Herpesvírus humano
• Link de acesso: http://repositorio.unifesp.br/handle/11600/9743

Objectives: To evaluate the clinical and epidemiologic aspects of human herpesvirus-6 infection (HHV-6) after renal transplantation, its relation with the replication of citomegalovirus (CMV), as well as the use of nested polimerase chain reaction (PCR) and real time PCR as diagnostic methods of active infection. Methods: A prospective descriptive study was conducted at São Paulo Hospital and Hospital do Rim e Hipertensão (affiliated to the Federal University of São Paulo), with accompaniment of 30 consecutive recipients of renal transplant. HHV-6 serology of the living donors and recipients were collected just before transplantation and the patients were monitored every week in the first two months and every other week for two more months posttransplant, with nested (qualitative) and real time (quantitative) PCR for HHV-6 in plasma and “buffy coat” (BC) samples and with antigenemia for CMV. Results: HHV-6 seroprevalence in the living donors was 100% IgG positive and IgM negative and in the recipients was 96,6% IgG positive and 13.3% IgM positive. The viral DNA detention in samples of BC through the PCR was more frequent in relation to the plasma samples: in the living donors just before transplantation, respectively 88.2% and 22.2% and in the recipients post-transplant, respectively 96.6% and 70%, which is probably associated to the intracellular detention of latent DNA in the BC samples. Considering active infection as the viral DNA detention in plasma samples, the incidence of HHV-6 infection was 70% when nested PCR was used. However, it was observed that most of the viral replication episodes were isolated and that only 26% of the patients presented susteined replication. When the real time PCR assay was used lower sensitivity was observed (36.6%) in relation to nested PCR, which can be explained by the smallest limit of detention presented by the real time PCR assay used in this study. In the univariada analysis, viral load of HHV-6 > 10.000 copies mL/plasma in the recipients just before transplantation was a risk factor associated with viral reactivation (p= 0,046) and was also a predictor of sustained viral replication (p=0,034), as well as positive IgM serology in the recipients pre-transplant was a predictive factor for sustained viral replication (p=0,005). The average time for viral DNA detention in plasma posttransplant was 31 days and 80% of the infection episodes were assymptomatic. CMV infection was more frequent (52.3%) in the group of patients that presented reactivation of the HHV-6 in comparison with the group that did not present (33%) and symptomatic CMV infection was also more frequent in the co-infected patients (36%) in relation to thepatients who had only presented CMV infection (0%). Conclusions: HHV-6 infection in the renal transplant is common and benign, the reactivations post-transplant are precocious and related to little clinical repercussion. The laboratorial diagnosis of this infection must be carried out in consecutive plasma samples and not in isolated samples.