CD28 positive, cytomegalovirus specific cytotoxic T lymphocytes as a novel biomarker associated with cytomegalovirus viremia in kidney allorecipients.

BACKGROUND: CMV infection remains major complication after kidney transplantation, thus diagnostics tools that would improve identification of individuals at risk of development of CMV - related complications are useful. For this reason, searching for proper immunological biomarkers candidates gives hope to individualize antiviral therapy and minimize side effects of antiviral drugs.

OBJECTIVES: The purpose of this research was to assess immune assays that can be used to predict the likelihood of CMV viremia after kidney allotransplantation.

STUDY DESIGN: In the study, immunological markers of CMV viremia were assessed in 52 kidney transplant recipients during two years lasting follow-up. Immunological markers associated with viral infection, like lymphocytosis, cytotoxic T lymphocytes (CTL) and serum cytokines levels were compared with less common immunological assays, like activated T lymphocytes, CMV-specific CTL stratified according to naïve/memory phenotype. The test to assess expression of CD28 antigen on CTL, as a possible additional marker of CMV-specificity, was developed.

RESULTS: CD28-positive CMV-specific CTL have been found the most useful marker for CMV viremia prediction. Tested value of 3 cells/μl was found to be most suitable for CMV activation assessment with acceptable sensitivity and specificity.

DISCUSSION: This preliminary report suggests that CD28-positive CMV-specific CTL could be put at the first line, as possible novel marker associated with CMV viremia development.