Performance of the QuantiFERON-Cytomegalovirus (CMV) Assay for Detection and Estimation of the Magnitude and Functionality of the CMV-Specific Gamma Interferon-Producing CD8⁺T-Cell Response in Allogeneic Stem Cell Transplant Recipients

Abstract

The performance of the QuantiFERON-cytomegalovirus (CMV) assay was compared to that of a flow cytometry intracellular cytokine staining (ICS) method for the detection of CMV-specific gamma interferon (IFN-␥)-producing CD8؉ T-cell responses in allogeneic stem cell transplant (allo-SCT) recipients and for estimations of their magnitude and functionality. A total of 90 whole-blood specimens from 23 allo-SCT recipients was analyzed by both methods. Overall, the percentage of specimens that yielded concordant results by both methods was 68.8% ( -cell responses, as quantitated by ICS. In summary, the data indicated that the QuantiFERON-CMV assay is less sensitive than the ICS method for the detection of CMV-specific IFN-␥-producing CD8؉ T-cell responses in the allo-SCT setting. Nevertheless, it allowed the estimation of the total and polyfunctional CMV-specific IFN-␥-producing CD8 ؉ T-cell responses in specimens that tested positive by both methods. The assessment of the magnitude and the functionality of T-cell immunity against cytomegalovirus (CMV) is emerging as a clinically useful tool for the therapeutic management of CMV infection in the allogeneic stem cell transplantation (allo-SCT) setting (7, 13). The monitoring of CMV-specific CD8 ϩ or CD4 ϩ T-cell responses may allow for the optimization of preemptive antiviral therapy regimens on an individual basis and the identification of patients who may benefit from prophylactic antiviral or adoptive T-cell transfer therapeutic strategies (1,7,13). In recent years, several methods have been developed for the ex vivo quantitation and functional characterization of T-cell responses, among which flow cytometry for surface immunophenotyping and intracellular cytokine staining (ICS) are currently considered the "gold standard" (13). The QuantiFERON-CMV assay (Cellestis Ltd., Melbourne, Australia) is a commercially available test that allows the inference of the size of the CMV-specific T-cell response by quantitating the level of gamma interferon (IFN-␥), produced mostly by CMV-specific CD8 ϩ T cells, upon the stimulation of whole blood with a number of immunogenic peptides mapped within IE-1, IE-2, pp65, pp50, and gB and restricted by several widespread HLA-I haplotypes (17). The performance of the QuantiFERON-CMV assay has been assessed mostly in the solid-organ transplant (SOT) setting (see reference 4 for a review). Recently reported data, although preliminary, lend support to the suitability of the QuantiFERON-CMV assay for the monitoring of the CMV-specific IFN-␥-producing CD8 ϩ T-cell responses in allo-SCT recipients (2). Nevertheless, it is largely unknown how this method compares to ICS assays for such a purpose. In previous studies, we reported the development and clinical utility of an ICS assay for the quantitation of CMV-specific IFN-␥-producing CD8 ϩ and CD4 ϩ T cells (11,12,(14)(15)(16). The assay was found to reliably predict protection from the development of CMV DNAemia in allo-SCT recipients, and it was recently used in the setting of a novel strateg...

Functional patterns of cytomegalovirus (CMV) pp65 and immediate early‐1‐specific CD8+ T cells that are associated with protection from and control of CMV DNAemia after allogeneic stem cell transplantation

“…Fourth, we found that the PPV and NPV of the detection of total IFN‐γ‐producing CD8 + T cells (and also total TNF‐α‐producing CD8 + T cells) for the occurrence of CMV DNAemia were comparable to those of the detection of polyfunctional CD8 + T cells (either CD107a + or CD107a − ). This was previously shown by our group for IFN‐γ‐producing CD8 + T measured by the QuantiFERON CMV assay .…”

CMV-specific immune reconstitution following allogeneic stem cell transplantation

“…This assay is analogous to the QuantiFERON-TB assay that has been widely adopted for tuberculosis. Although QantiFERON-CMV is less sensitive than flow cytometry assays, 96 it is simple and reproducible and has been validated in HSCT recipients with similar results to other immune monitoring assays. 97 There are no studies that yet conclusively demonstrate the safety of ceasing CMV monitoring based solely on the demonstration of CMV immunity.…”

Evaluation of T Cell Immunity against Human Cytomegalovirus: Impact on Patient Management and Risk Assessment of Vertical Transmission

“…In comparison to ICS, QT is as specific but less sensitive [68]. However, ICS is definitely more difficult to standardize and not suitable for automation.…”