Feasibility of using saliva for Cytomegalovirus detection and genotyping in pediatric hematopoietic stem cell transplant recipients

Human Cytomegalovirus (HCMV) is a major viral pathogen that causes severe complications in immunosuppressed individuals, particularly hematopoietic stem cell transplant recipients. In these patients, Cytomegalovirus has been associated with gastroenteritis, pneumonia, hepatitis, and even graft-versus-host disease, and a possible relationship has been identified between Cytomegalovirus genotypes and clinical course, complications and outcome. Early detection of Cytomegalovirus infection or reactivation is important, and previous findings show that it could potentially be evaluated in saliva, where HCMV causes asymptomatic viral shedding. Since saliva can be collected easily and safely, it is important to evaluate its potential for HCMV detection and genotyping, especially in pediatric patients who are receiving hematopoietic stem cell transplantation. Aim: The purpose of this study was to evaluate the feasibility of using saliva to detect and genotype HCMV in a cohort of pediatric hematopoietic stem cell transplant recipients (HSCTR). Materials and Method: This study was conducted at Fundación Hospital Pediátrico la Misericordia, in Bogota, Colombia. Stimulated saliva samples were collected once a week and subjected to HCMV detection by qualitative PCR and genotyping by nested PCR followed by sequencing. Finally, a phylogenetic tree was constructed. Results: Twenty patients were enrolled, and 105 saliva samples were collected, of which 29 were positive for HCMV. Twelve patients had at least one positive sample. The gB1 genotype was identified with no coinfection with any other genotype. Phylogenetic analysis showed that some saliva samples were closer to the sequence reported for the Towne laboratory strain, while others were closer to the Merlin strain, with slight differences between them. Conclusions: It was demonstrated that saliva can be used to detect and genotype Cytomegalovirus in pediatric transplant recipients, and that sample collection is easy, with no risk of bleeding or discomfort in the pediatric patients evaluated.