Lack of cytomegalovirus (CMV)-specific cell-mediated immune response using QuantiFERON-CMV assay in CMV-seropositive healthy volunteers: fact not artifact

Ana B. Pérez,Jorge Valle-Arroyo,Sara Cantisán,Julián Torre-Cisneros,Rafael González,Gema Fornés,Rocío Aguado,Aurora Páez-Vega

doi:10.1038/s41598-020-64133-x

Abstract

The QuantiFERON-CMV (QF) assay measures cell-mediated immunity against cytomegalovirus (CMV-CMI), which is particularly useful in individuals susceptible to CMV infection such as transplant patients. A positive QF result identifies patients that are better protected against CMV infection. However, the significance of a negative QF result in CMV-seropositive individuals needs to be clarified. CMV-CMI was analyzed in healthy subjects using the QF assay, and, in parallel, the Flow-cytometric Assay of Specific Cell-mediated Immune response in Activated whole blood (FASCIA). FASCIA assay measures T-cell proliferation using CMV lysate as stimulus whereas QF assay use a mix of peptides. A total of 93 healthy volunteers were enrolled, and 13/71 CMV-seropositive individuals (18.3%) showed humoral/cellular discordance using QF assay (CMV+ QF−). Interestingly, with FASCIA assay CD4+ and CD8+ T-cell proliferations were lower in CMV+ QF− than in CMV+ QF+ individuals. Furthermore, CMV+ QF− volunteers had a lower level of anti-CMV IgG than CMV+ QF+ subjects. Discordant CMV+ QF− volunteers can be defined as low responder individuals since they show lower CMV-specific humoral and cellular immune responses in comparison to CMV+ QF+ individuals. Immune discordance shows the high heterogeneity of immunity to CMV in healthy subjects.

Highlights

In the last years, a variety of assays have been developed to measure cell-mediated immunity against cytomegalovirus (CMV-CMI), where the basic principle is the CMV-specific stimulation of T cells for 6–24 hours in cell culture[1,2]
This study evaluates humoral/cellular CMV immunity discordance in CMV-seropositive healthy volunteers using, in parallel, two techniques that measure CMV-CMI in different ways (IFNG release vs. lymphocyte proliferation)
The objective was to evaluate whether a negative QF result in CMV-seropositive individuals (CMV+ QF−) is an artifact of the QF assay, as suggested by some authors[15,17], or it identifies individuals with immunological characteristics different from non-discordant individuals (CMV+ QF+)

Summary

Introduction

A variety of assays have been developed to measure cell-mediated immunity against cytomegalovirus (CMV-CMI), where the basic principle is the CMV-specific stimulation of T cells for 6–24 hours in cell culture[1,2] These techniques have been shown to be useful in individuals such as transplant patients who are susceptible to CMV infection, since they identify who is better protected against CMV infection after transplantation, as has been reported in international guidelines on the management of CMV in solid organ or stem cell transplantation[3,4]. Some authors argue that negative results might be related to the inability of certain individuals to recognize the peptides of the QF assay[15] To clarify this point, we analyzed CMV-CMI response with QF assay, and, in parallel, with the Flow-cytometric Assay of Specific Cell-mediated Immune response in Activated whole blood (FASCIA), which measures the lymphocyte proliferative response after stimulation with CMV lysate[16]

Objectives

Methods

Conclusion