The first T cell response test to the virus behind Covid-19 has received emergency approval for use in the United States, creating another option for people to find out if they have had the disease.
Adaptive Techologies, a Seattle-based biotechnology company, worked with Microsoft to create the blood test, which may be more accurate than some of the antibody tests on the market.
In addition to creating antibodies, the immune system produces T cells in response to infection. T cells are white blood cells that can directly kill infected cells or help B cells stimulate antibody production.
Adaptive Chief Medical Officer Lance Baldo said T cells were important because they have a “very long memory”, seeming to stay in the body for at least six to nine months. Since the pandemic has only been around for a year, it could last even longer.
Baldo said it could be especially helpful for people with “long Covid” – with symptoms that persist for months – who may not have tested positive at the time. It could help shape their care and, in the United States, it could influence what insurers pay.
“You have these people with long-term Covid, they don’t know if they’ve ever really been infected, their antibodies are definitely gone, they won’t have a positive PCR. [diagnostic test], and they just call us and say, ‘I want to know if three months ago, six months ago, nine months ago, I actually had the coronavirus,’ ”he said.
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Adaptive’s lab tests, which were previously available from janitorial offices, can now be ordered by physicians across the United States.
The Food and Drug Administration’s Emergency Use Clearance Comes Next a study has shown that T cells can play an important role in the immune response to new variants. Researchers at the La Jolla Institute for Immunology and the University of California said they found T-cell responses in vaccinated or previously infected people to be equally robust with the variants first identified in the UK, Brazil, South Africa and California.
Adaptive claims that its research, which has not yet been peer reviewed, has shown that its test detects 97% of people with the disease, compared to antibody tests which vary between 77 and 97%. The proportion of false negatives was less than 1%.
There hasn’t yet been enough research to know whether the discovery of these T cells means people are immune to the Sars-Cov-2 virus. But Adaptive is hoping that patients who take the test opt for research, which will allow the company to track them and see if there are any who develop Covid-19.
Adaptive is also working with vaccine developers, who have so far focused on whether their injections elicit an antibody response, to see if they also perform a T cell response.
Microsoft’s machine learning tools have helped adaptively map the body’s immune system. Adaptive also plans to create tests for the response of T cells to other infectious diseases, such as Lyme disease and autoimmune diseases.