Private Harley Street Clinic is offering T Lymphocyte (T-cell) testing to determine previously undetected T lymphocyte immune responses to COVID-19.

The test could be a game changer for some COVID-19 ‘long haulers’ and for people who have not yet had a clear answer on whether they were previously infected with the virus.

T-cells are a type of white blood cell that forms an essential part of the human immune system. T-cells (and B-Cells) are lymphocytes which govern the bodies’ response to foreign antigens. Until now the only test available to assess an immune response was based on the presence of antibodies which are produced by B lymphocytes. We have millions of T-Cells which originate in bone marrow and once they encounter an antigen, they secrete chemical messengers which stimulate several different immune responses. Regulatory T cells act to control immune reactions and Cytotoxic T cells bind together and kill infected cells and cancer cells.

Here are the five things to know about the potential of T-Cell immunity:

Confirmation of COVID-19 infection status

This test could bring clarity to many people who believe that they have had COVID-19 but have no proof of having the virus. Despite the whirlwind beginning of the pandemic, and lack of testing in 2020, it is important for people’s medical history, understanding their personal immunity status and for scientists understanding the spread of the disease to have a true picture of infection.               

Long COVID-19

For those people suffering from a bizarre list of long, persisting and sometimes debilitating symptoms, accurate knowledge of infection status is extremely helpful in knowing where people stand. Until now, if you had long-COVID-19 symptoms but no antibodies you will have been potentially misdiagnosed with something else. Scientists are concerned that the long COVID-19 could be separate or a second epidemic to emerge from the first. 

Dr Mark Ali, medical director of the Private Harley Street Clinic, and a Cardiothoracic Surgeon of 30 years’ experience has also completed a BSc degree in Immunology and Molecular Biology, he says: "Identification of a T cell response to COVID-19 is seen as the missing link in testing. We have tracked so many people who are sure that they have had COVID-19 but test negative for antibodies and the antigen itself, perhaps because they were tested too late to pick up the virus or it was a false negative.”               

Future-use

It could also help find and influence better treatments for those who have been infected. The test is administered via a venous blood draw. In the USA T-Cell DNA is extracted and sequenced with Microsoft's artificial intelligence, mapping out the immune system's "massive black box" data into navigable science. The potential for tracking and improving understanding of virus spread is important.

Arming against infection

The ability to recognise and record T-Cell immunity will shed more light on how that system can be better targeted, enhanced, armed and ready against future infections. 

Dr Ali says: “We need to know the full extent of numbers of people who have had a T-Cell response to better understand and protect our society from future viruses.”

Monitoring the development of T-Cell

T-Cells can continue to be monitored in the body after infection for severity of response to the virus and vaccine efficacy and durability. 

Dr Ali says: “Because of the pandemic’s length and changing mutations people are quite rightly concerned about their COVID-19 immunity status. It is helpful, but also empowering for people to know if they have had COVID-19 and also generated an immune response. In time, T Lymphocyte testing may also provide us with a more realistic picture of how many people have had the virus, and how our bodies successfully fight and kill it.”

The new test is called the T-SPOT.COVID test and will enable individuals themselves to discover whether they have mounted a T cell led immune response to COVID-19- as opposed to an antibody response which is the other way that the immune system deals with COVID-19 viral infection.

The T-SPOT.COVID test has been developed by Oxford Immunotec Global PLC producers of the T-SPOT.TB test, which was originally used for diagnosing infection with Tuberculosis. The test is highly accurate and was positive in 96.6% of a group of previously infected individuals <60 days after infection and 83.3 % at >60 days after infection:

• The T-SPOT.COVID test is available at The Private Harley Street Clinic for £195.00
• The new ELISPOT based test is intended for qualitative detection of a cell mediated (T cell) immune response to SARS-CoV-2 in human whole blood
• The T cell test (the T-SPOT.COVID test) is CE marked and approved for use in the UK by the MHRA
• This requires a venous blood sample taken from a vein by a qualified medical professional
• Results are returned within 48 hours.