Quantification and prognostic significance of interferon-γ secreting SARS-CoV-2 responsive T cells in hospitalised patients with acute COVID-19

Little is known about T-cell responses during acute coronavirus disease-2019 (COVID-19). We measured T-cell interferon gamma (IFN-γ) responses to spike 1 (S1), spike 2 (S2), nucleocapsid (N) and membrane (M) SARS-CoV-2 antigens using the T-SPOT® Discovery SARS-CoV-2 assay, a proven EliSPOT technology, in 114 hospitalised adult COVID-19 patients and assessed their association with clinical disease phenotype. T-SPOT® Discovery SARS-CoV-2 responses were detectable within 2 days of a positive PCR and did not correlate with vaccination status or symptom duration. Higher responses to S1 protein associated with a higher symptom burden, and serum IL-6 levels. Despite treatment with dexamethasone this subgroup was also at greater risk of requiring continuous positive airway pressure (CPAP) in the days following sampling. Higher T-cell responses measured using T-SPOT® Discovery SARS-CoV-2 associate with progressive disease in acute COVID-19 disease and may have utility as a prognostic biomarker that should be evaluated in larger cohorts.