New Blood Test for Early Immune Response to SARS-CoV-2 Could Enable Early Detection of Serious COVID-19 Patients

A new way of testing whether the immune system of COVID-19 patients is preparing to fight the SARS-CoV-2 virus could be used for early identification of those patients whose immune systems are not responding appropriately and are therefore, at a higher risk of serious infection.

The prototype test developed by researchers at the QIMR Berghofer Medical Research Institute (Brisbane, Australia) detects high levels of two key chemical signals that are produced by T cells when they recognize SARS-CoV-2-infected cells and begin fighting the infection. For their study, the researchers examined blood donated by recovered COVID-19 patients in order to find out which combination of viral peptides can be used to stimulate T cells in the laboratory and allow researchers to measure their response to SARS-CoV-2.


"We isolated the T cells from the donated blood, exposed them to viral peptides, and measured the production of a number of different signaling molecules. We then compared the levels produced by T cells from the recovered COVID-19 patients with levels released by T cells from 20 healthy donors who had never been infected with SARS-CoV-2," said Associate Professor Corey Smith who was the study leader and is the head of QIMR Berghofer's Translational and Human Immunology Group. "We found that T cells from people who had recovered from COVID-19 produced larger amounts of the signaling molecules interferon gamma and interleukin-2, which are involved in killing virus-infected cells and encouraging other T cells to come to the infected area."

"We screened a range of SARS-CoV-2 peptides to work out which combination could be used to detect a successful T cell immune response, which we can then measure by detecting these two key signaling molecules."

The researchers believe that a blood test for early immune response to the virus could help countries that are witnessing second and third COVID-19 waves.

"Now that we've refined a way to detect whether or not T cells are reacting to SARS-CoV-2, we believe this information could be used to develop a blood test," said QIMR Berghofer researcher Dr. Katie Lineburg. "A blood test could help doctors identify patients whose T cells have not started mounting an immune response and who are therefore not fighting the virus and are at higher risk of becoming seriously unwell. Those patients could then be monitored more closely to ensure they receive treatment early, rather than waiting until they experience severe symptoms."

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QIMR Berghofer Medical Research Institute