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

Abstract

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 potential diagnostic tool. Methods We evaluated IFN-γ levels after stimulating whole-blood with spike and remainder-antigens peptides megapools (MP) derived from SARS-CoV-2 sequences; IL-1β, 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 FGF, G-CSF, GM-CSF, IFN-γ, IP-10, MCP-1, MIP-1α, MIP-1β, PDGF, RANTES, TNF-α, VEGF were also evaluated. Results IFN-γ-response to spike and remainder-antigens MPs was significantly increased in 35 COVID-19-patients compared to 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-γ-response to SARS-CoV-2-unrelated antigens CMV and SEB was similar in COVID-19 compared to NO-COVID-19-invididuals (median CMV: 3.46 versus 5.28, p=0.16; median SEB: 12.68 versus 15.05; p=0.1). In response to spike-MPs in COVID-19- compared to “NO COVID-19”-individuals, we found significant higher median of IL-2 (50.08 vs 0, p=0.0018), IFN-γ (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 to 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.

In-vitro evaluation of the immunomodulatory effects of Baricitinib: Implication for COVID-19 therapy

“…To better address the effect of baricitinib on the response to SARS-CoV-2-peptides, we analyzed the IFN-γ response considering only the IFN-γ values >0 IU/mL (Supplementary Figure 1 and 2). In COVID-19, the decreasing effect of baricitinib was observed mainly in patients with an IFN-γ response higher than the cut-off already published for both spike-antigen (0.16 IU/mL) (spike median: 0.31, IQR: 0.12-1.73; spike+baricitinib 10 nM median 0.17, IQR: 0.05-1.49; spike+baricitinib 1000 nM median 0.1, IQR: 0-0.18) and remainder-antigens-MPs (0.095 IU/mL) (remainder-antigens median: 0.26, IQR: 0.09-1.00; remainder-antigens+baricitinib 10 nM median 0.09, IQR: 0.03-0.3; remainder-antigens+baricitinib 1000 nM median 0.07, IQR: 0-0.27) 20 (Supplementary Figure 2A-B, red lines indicate responses over the cut-off). Similar results were obtained in “NO COVID-19” (spike median: 0.08, IQR: 0.02-0.4; spike+baricitinib 10 nM median 0.04, IQR: 0-0.33; spike+baricitinib 1000 nM median 0.02, IQR: 0-0.13; remainder-antigens median: 0.04, IQR: 0.01-0.16; remainder-antigens+baricitinib 10 nM median 0.03, IQR: 0.01-0.08; remainder-antigens+baricitinib 1000 nM median 0.01, IQR: 0-0.04) (Supplementary Figure 2C-D).…”

“…This study was conducted also evaluating samples from COVID-19 patients and “NO COVID-19” individuals who were part of a previous cohort (study approval number 59/2020). 20 All the enrolled individuals provided an informed written consent. All the participants’ data were anonymized and identified by codes.…”

“…In “NO COVID-19”-group, samples with a positive ELISA score, were tested with an indirect immunofluorescence (IF) as previously described. 20 Although IF has been described as a test with high sensibility/specificity, 32 here was used as confirmatory test as it is an home-made test.…”

“…T-cell immune response specific to SARS-CoV-2 antigens was extensively studied 15 , 16 , 17 , 18 and we and others also showed that SARS-CoV-2 specific T-cell responses may be measured in patients with COVID-19 using a whole-blood based platform. 19 , 20 The whole blood assay is a valid approach to measure antigen-specific responses that has been explored in the field of several infectious diseases. 21 , 22 , 23 , 24 , 25 In a disease different from COVID-19 as tuberculosis, T-cell-specific response decreases overtime and this associates with cure.…”

Differential T cell reactivity to seasonal coronaviruses and SARS-CoV-2 in community and health care workers

“…Further optimizations are in progress, based on inclusion of specific viral antigens and exclusion of specific epitopes. We anticipate that in the future we will be able to combine these improved pools, perhaps in conjunction with recently described whole blood assays ( 63 , 64 ) to easily, accurately and independently assay levels of T cell reactivity to SARS-CoV-2 and CCC in different populations, such as pediatric cohorts versus older subjects, cohorts from different geographical locations associated with differential exposure to CCC, differential disease incidence, and other variables.…”