title: Quantification of CD8(+)CD38(+) T lymphocytes by flow cytometry does not represent a good biomarker to monitor the reactivation of cytomegalovirus infection after allogeneic hematopoietic stem cell transplantation.
abstract: BACKGROUND
  Infection/reactivation of cytomegalovirus is a major cause of morbidity and mortality in immunocompromised transplant patients. It has already been observed in kidney and liver transplantation patients that cytomegalovirus disease is accompanied by significant increases in circulating CD8(+)CD38(+) T lymphocytes. There are no reports that study CD8(+)CD38(+) T lymphocytes to monitor/diagnose cytomegalovirus disease in hematopoietic stem cell transplantation patients.
  
  
  OBJECTIVE
  The aim of this study was to evaluate some cellular activation markers on circulating mononuclear cells (CD38 and HLA-DR) in patients submitted to hematopoietic stem cell transplantation and to establish any correlation with cytomegalovirus disease as diagnosed by antigenemia.
  
  
  METHODS
  Blood samples of 15 transplant patients were analyzed by flow cytometry using anti-CD3, anti-CD4, anti-CD8, anti-CD38, CD16, CD56 and anti-HLA-DR monoclonal antibodies and the results were evaluated in respect to cytomegalovirus antigenemia measured by indirect immunofluorescence. Minitab for Windows was used for statistical analysis and a p-value < 0.05 was considered significant.
  
  
  RESULTS
  Patients with positive antigenemia did not show any significant increase in the percentages of cells expressing the CD38 or HLADR activation markers when compared to patients with negative antigenemia. On the contrary, all patients showed high percentages of these cells independent of the presence of cytomegalovirus disease.
  
  
  CONCLUSIONS
  This study suggests that the investigation of these lymphocyte sub-populations in patients submitted to hematopoietic stem cell transplantation does not seem to contribute to the early identification of cytomegalovirus disease.
authors.affiliation: Universidade Federal de Minas Gerais - UFMG, Belo Horizonte, MG, Brazil.
authors.forename: Vânia Abadia Soares
authors.initials: VA
authors.lastname: Lino
authors.forename: Silvana Maria Eloi
authors.initials: SM
authors.lastname: Santos
authors.forename: Henrique Neves da Silva
authors.initials: HN
authors.lastname: Bittencourt
authors.forename: Maria Luiza
authors.initials: ML
authors.lastname: Silva
authors.forename: Tiago
authors.initials: T
authors.lastname: Spizziri
authors.forename: Raquel
authors.initials: R
authors.lastname: Bretas
authors.forename: Suzane Pretti Figueiredo
authors.initials: SP
authors.lastname: Neves