Validation of the Suitability of Lophius Kits T-Track® CMV and T-Track® EBV to Assess the Functionality of Cell-Mediated Immunity (CMI) in Hemodialysis Patients

Abstract

Introduction: Inadequate impairment of cell-mediated immunity (CMI) by immunosuppressive therapy is a major cause of severe clinical complications in solid organ transplantation. Thus, accurate assessment and monitoring of CMI in the course of immunosuppressive treatment may not only help to predict the onset of these complications, but also to adjust immunosuppressive and antiviral therapy. The aim of the presented cross sectional multicenter study in a cohort of hemodialysis patients was to evaluate the suitability of the novel immune monitoring tools T-Track® CMV and T-Track® EBV to assess the functionality of CMI in a clinically relevant collective of patients. Methods: In this study, test sensitivity of T-Track® CMV and T-Track® EBV assays was examined in a cohort of 124 hemodialysis patients aged between 24 and 88 years and compared with that of the T-cell monitoring test Quantiferon®CMV and a panel of 6 preselected CMV tetramers. T-Track® CMV and T-Track® EBV are based on the stimulation of freshly isolated PBMC with a panel of urea-formulated CMV and EBV proteins, respectively and the quantification of protein-reactive leukocytes using the sensitive IFN-γ ELISpot technology. The urea-formulated proteins are processed by cross-presentation, enabling the simultaneous reactivation of a broad spectrum of antigen-reactive leukocytes including T-helper and cytotoxic T-cells, but also NK- and NKT-cells. Results: Herein, positive T-Track® CMV or T-Track® EBV test results were obtained in 88% of CMV (59/67) or 86% of EBV-seropositive hemodialysis patients (102/118), respectively. In addition, also 9/57 and 0/1 seronegative dialysis patients showed significant numbers of CMV or EBV-responsive cells, which may have been activated by repeated non infective exposure to the pathogen. Quantiferon® CMV and CMV tetramers revealed assay sensitivities of app. 73% (45/62) and 76% (40/53), respectively. In contrast to Quantiferon® CMV and CMV tetramers allowing the enumeration of peptide-specific T-cells, T-Track® CMV assays provide information about functionality of the network of different subpopulations of CMV and EBV protein-reactive effector cells and can be used in a high percentage of hemodialysis patients. Conclusion: Thus, T-Track® assays represent novel valuable tools to assess functionality of CMV/EBV-responsive CMI in immunocompromised transplant recipients and may help to guide immunosuppressive and antiviral therapy.