A whole blood test to measure SARS-CoV-2-specific response in COVID-19 patients

Objectives: To examine whether specific T cell responses to SARS CoV 2 peptides can be detected in COVID 19 using a whole blood experimental setting, which may be further explored as a potential diagnostic tool. Methods: We evaluated interferon (IFN) ( )gamma levels after stimulating whole blood with spike and remainder antigens peptides megapools (MP) derived from SARS CoV 2 sequences; interleukin (IL) 1 beta, IL 1RA, IL 2, IL 4, IL 5, IL 6, IL 7, IL 8, IL 9, IL 10, IL 12p70, IL 13, IL 15, IL 17A, eotaxin, basic fibroblast growth factor (FGF), granulocyte colony stimulating factor (G CSF), granulocyte macrophage colony stimulating factor (GM CSF), IFN y, Interferon gamma induced protein 10 (IP 10), monocyte chemoattractant protein 1 (MCP 1), macrophage inflammatory protein (MIP) 1 alpha, MIP 1 beta, Platelet derived growth factor (PDGF), RANTES (regulated on activation, normal T cell expressed and secreted), tumour necrosis factor alpha (TNF alpha), vascular endothelial growth factor (VEGF) were also evaluated. Results: IFN gamma response to spike and remainder antigens MPs was significantly increased in 35 COVID 19 patients compared with 29 'no COVID 19' individuals (medians spike MP: 0.26 vs 0, p = 0.0002; medians remainder antigens MP: 0.07 vs 0.02; p = 0.02). This response was detected independently of patients' clinical parameters. IFN gamma response to SARS CoV 2 unrelated antigens cytomegalovirus (CMV) and Staphylococcal Enterotoxin B (SEB) was similar in COVID 19 compared with 'no COVID 19' individuals (median CMV: 3.46 vs 5.28, p = 0.16; median SEB: 12.68 vs 15.05; p = 0.1). In response to spike MPs in COVID 19 compared with 'no COVID 19' individuals, we found significant higher median of IL 2 (50.08 vs 0, p = 0.0018), IFN gamma (90.16 vs 0, p = 0.01), IL 4 (0.52 vs 0, p = 0.03), IL 13 (0.84 vs 0, p = 0.007) and MCP 1 (4602 vs 359.2, p = 0.05). Conclusions: Immune response to SARS CoV 2 peptides in a whole blood assay is associated with COVID 19 and it is characterized by both Th1 and Th2 profile. This experimental approach may be useful for developing new T cell based diagnostic tests for disease and vaccine settings. (C) 2020 Published by Elsevier Ltd on behalf of European Society of Clinical Microbiology and Infectious Diseases.

Automated summary

The study showed that specific T cell responses to SARS CoV 2 peptides can be detected in COVID-19 patients and are significantly different from individuals without COVID-19. This immune response exhibits characteristics of both Th1 and Th2 profiles, potentially serving as a new T cell-based diagnostic tool.