Abstract
BackgroundBased on sequence variation in the UL55 gene that encodes glycoprotein B (gB), human cytomegalovirus (CMV) can be classified into four gB genotypes. Previous studies have suggested an association between CMV gB genotype and clinical outcome in patients who underwent an allogeneic hematopoietic stem cell transplant (HSCT). The goals of this study were identify patients with active infection caused by CMV in recipients of HSCT; determine the prevalence of CMV genotypes in the study group; correlate genotype with CMV disease, acute GVHD and overall survival.MethodsThe diagnosis of active CMV infection after allogeneic HSCT was detected by antigenemia (AGM) and/or nested-PCR (N-PCR). Positive samples from patients with active CMV infection were submitted to genotyping using N-PCR to amplify a region of UL55, followed by restriction analysis based on HinfI and RsaI digestion. Real-time PCR (qPCR) was used to determine the viral load during active CMV infection and antiviral treatment.ResultsSixty-three allogeneic HSCT recipients were prospectively evaluated; 49/63 (78%) patients were infected with CMV genotypes – gB1 19/49 (39%), gB2 17/49 (35%), gB3 3/49 (6%), gB4 7/49 (14%) – and 3 (6%) had mixed CMV genotypes (gB1 + gB3, gB1 + gB4 and gB2 + gB4). Characterized by gastrointestinal disease, CMV disease occurred in 3/49 (6.1%) patients, who had CMV gB3 genotype. These gB3 genotype patients presented an increasing AGM number, mean 125 (± 250) (P = 0.70), and qPCR copies/ml, mean 37938 (SD ± 50542) (P = 0.03), during antiviral treatment, when compared with other CMV genotypes. According to CMV genotypes, stratified overall survival was 55% for gB1, 43% for gB2; 0% for gB3 and 57% for gB4 (P = 0.03).ConclusionsOne of the restrictions of the presented study was the low number of CMV gB sub-cohorts). However, we demonstrated that the frequency of active CMV infection in this HSCT population was high, and the most prevalent genotype in these patients with active CMV infection was gB1 and gB2 genotype (74%). In Brazil, HSCT recipients seem to carry mainly gB1 and gB2 CMV genotype.
Highlights
Based on sequence variation in the UL55 gene that encodes glycoprotein B, human cytomegalovirus (CMV) can be classified into four gB genotypes
This study aimed to prospectively analyze gB gene of CMV in allogeneic hematopoietic stem cell transplant (HSCT) recipients with human active CMV infection to determine the distribution of gB genotypes and their possible impact on overall survival, acute GVHD and CMV disease
Among the 63 patients, 49 (78%) had active CMV infection detected by AGM and/or N-polymerase chain reaction (PCR) tests
Summary
Based on sequence variation in the UL55 gene that encodes glycoprotein B (gB), human cytomegalovirus (CMV) can be classified into four gB genotypes. Previous studies have suggested an association between CMV gB genotype and clinical outcome in patients who underwent an allogeneic hematopoietic stem cell transplant (HSCT). Cytomegalovirus (CMV) remains the most important cause of serious viral infections in allogeneic hematopoietic stem cell transplant (HSCT) recipients [1]. It was reported that the existence of CMV variants played an important role in the pathogenesis of diseases, as these variants affected several genes that might be responsible for different diseases related to active CMV infection [7,8,9,10]. GB genotypes display significant amino acid variations in their variable domains, including changes that affect glycosylation sites, the functional consequences of these variations have not yet been explored [14,15,16,17,18,19,20,21,22,23,24]
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