Accuracy of QuantiFERON SARS-CoV-2 research use only assay and characterization of the CD4+ and CD8+ T cell-SARS-CoV-2 response: comparison with a homemade interferon-γ release assay

• Published in: International journal of infectious diseases Vol. 122; pp. 841 - 849
• Main Authors: Aiello, Alessandra, Coppola, Andrea, Vanini, Valentina, Petrone, Linda, Cuzzi, Gilda, Salmi, Andrea, Altera, Anna Maria Gerarda, Tortorella, Carla, Gualano, Gina, Gasperini, Claudio, Scolieri, Palma, Beccacece, Alessia, Vita, Serena, Bruzzese, Vincenzo, Lorenzetti, Roberto, Palmieri, Fabrizio, Nicastri, Emanuele, Goletti, Delia
• Format: Journal Article
• Language: English
• Published: Canada Elsevier Ltd 01.09.2022; The Authors. Published by Elsevier Ltd on behalf of International Society for Infectious Diseases; Elsevier
• Subjects: CD4-Positive T-Lymphocytes; CD8-Positive T-Lymphocytes; COVID-19; COVID-19 - diagnosis; Humans; IFN-γ release assay (IGRA), T cell response; Interferon-gamma Release Tests; Mycobacterium tuberculosis; QuantiFERON SARS-CoV-2 tubes; SARS-CoV-2; Spike peptides; Tuberculosis; Whole-blood; COVID-19; QuantiFERON SARS-CoV-2 tubes; Whole-blood; Spike peptides; IFN-γ release assay (IGRA), T cell response
• ISSN: 1201-9712; 1878-3511; 1878-3511
• DOI: 10.1016/j.ijid.2022.07.049

•The QuantiFERON SARS-CoV-2 research use only assay response is mediated by CD4+ and CD8+ T cells.•Immune response to the antigen (Ag)2 tube is more accurate than that to the Ag1 tube.•Responses to QuantiFERON SARS-CoV-2 tubes are lower compared with a homemade test.•The QuantiFERON SARS-CoV-2 difference in accuracy is likely because of the peptide composition. Objectives: In this study, we aimed to characterize the SARS-CoV-2-specific T cell response detected by the QuantiFERON SARS-CoV-2 research use only assay in terms of accuracy and T cell subsets involved compared with a homemade interferon (IFN)-γ release assay (IGRA). Methods: We evaluated T cell response by the standardized QuantiFERON SARS-CoV-2 tubes (antigen [Ag]1 and Ag2) and a homemade IGRA quantifying IFN-γ response to SARS-CoV-2 spike peptides (homemade-IGRA-SPIKE test). We evaluated the T cell subsets mediating the specific response using flow cytometry. Results: We prospectively enrolled 66 individuals: COVID-19 or post-COVID-19 subjects and NO-COVID-19-vaccinated subjects, including healthy donors and immunocompromised subjects. The standardized kit detected 62.1% (41/66) of T cell responders. Ag2 tube showed a higher IFN-γ quantitative and qualitative response. Ag1 tube response was mainly mediated by CD4+ T cells; Ag2 tube response was mediated by CD4+ and CD8+ T cells. The homemade-IGRA-SPIKE test detected a higher number of responders (52/66, 78.8%) than the QuantiFERON SARS-CoV-2 assay (P = 0.056). The response was found in both T cell subsets, although a higher magnitude and response rate was observed in the CD4+ T cell subset. Conclusion: The QuantiFERON SARS-CoV-2 response is mediated by CD4+ and CD8+ T cells. A lower number of responders is found compared with the homemade-IGRA-SPIKE test, likely because of the different peptide composition.