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A new type of test may be more effective at determining whether someone already has coronavirus compared to widely used antibody tests.
The test looks for immune cells called T cells, which are a type of white blood cell that binds to and kills viruses.
New research from the manufacturer, Seattle-based Adaptive Biotechnologies, found the test to be eight times better at detecting a previous infection with COVID-19 than a commercially available antibody test.
Immunologists say the pre-printed study is yet to be peer reviewed, but the results look promising and could replace antibody testing as a way to find out how widespread the virus is in a community.
New type of test looks for T cells (pictured), a type of white blood cell that binds to and kills viruses, to determine if a person has been infected with coronavirus in the past
Of the 70 people who had confirmed cases of COVID-19, the T cell test correctly identified 97% of the cases and the antibody test correctly identified 77% of the cases. Pictured: Medical staff treat a patient with coronavirus in the COVID-19 intensive care unit at United Memorial Medical Center in Houston, Texas, November 2020
When a person is exposed to a virus, different parts of the immune system are called upon to fight it, including antibodies and other immune cells.
Most of the attention has been focused on antibodies because they are quick and inexpensive to detect. But they generally decrease over time.
“The source of the antibodies – the factory that makes them – dies within a few months,” Dr. Akiko Iwasaki, an immunologist at the Yale School of Medicine, told CNN.
Recent research, on the other hand, has shown that T cells may be sufficient to provide protection against the virus.
“For other viruses, they have been shown to persist for years. For this virus, we don’t know how long they last, but we would expect at least a few years, ”Iwasaki said.
A study published Tuesday in the UK, conducted by Oxford Immunotec and Public Health England, found that no participant with an elevated T cell response developed symptoms when infected with COVID-19.
In comparison, 20 people with low Responses of T cells, which presented with fever, cough, or shortness of breath.
However, isolating T cells takes a long time because there are billions of them that each recognize a different molecule and scientists need to identify the 20 or 30 that recognize the coronavirus.
After separating the immune cells from the blood samples, the cells are washed and counted.
Everyone is exposed to pieces of the virus to see which have an immunological response.
For the research, which has yet to be published and has not been funded by Adaptive, the team looked at samples from 2,200 people in Vo, Italy – which has become the epicenter of the pandemic in its region. from Veneto.
Of the 70 people who had had confirmed cases of the coronavirus, the test, called T-Detect, correctly identified 97% of the cases, missing only two of them.
By comparison, a commercial antibody test called DiaSorin only correctly identified 77% of cases, 16 missing.
This means the test is eight times more effective at determining whether a person has ever been infected with COVID-19.
What’s more, out of more than 2,000 people who tested negative for the virus, the T cell test gave positive results for 45 people.
Dr Lance Baldo, Adaptive’s chief medical office and co-author of the journal, told CNN that most of the 45 people never realized they were infected.
About half of them had mild symptoms or had lived with someone who tested positive for COVID-19, or both.
Adaptive said it plans to file an Emergency Use Authorization (EUA) application with the United States Food and Drug Administration this month.
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