Preliminary Data from Real-World Study Demonstrate T-cell Testing Outperforms Antibody Testing in Identifying Past SARS-CoV-2 Infections - Seite 2

An initial study published in Nature in June 2020 was conducted by the University of Padua in which nearly the entire population of Vo’, Italy (2,900 of the town’s 3,275 residents), was tested using PCR for SARS-CoV-2 infection at the beginning and end of a 14-day lockdown of the town, followed by longer-term clinical monitoring. At that time, 81 people in the town tested positive for the virus in at least one of the two surveys. Interestingly, more than 40% of those who tested positive were asymptomatic, guiding the town’s response to the then-emerging pandemic and driving their success in containment³.

In a follow-up study of 2,290 residents, including 70 of the 81 who tested positive by PCR, antibody testing with a EUA approved commercial test (IgG) and T-cell testing with Adaptive’s T-Detect Assay for past SARS-CoV-2 infection were performed approximately 60 days after PCR testing. The T-cell assay identified 97% (68/70) of past PCR-confirmed SARS-CoV-2 infections compared to 77% (54/70) with the antibody test. Notably, 24 of the 70 PCR -positive patients were asymptomatic, highlighting the added sensitivity of T-cell based testing to provide a more accurate representation of past infection in a community. The T-cell response was measured by the overall quantity of T cells as well as the number of unique virus-specific T cells. Convalescent subjects who were symptomatic and hospitalized with COVID-19 had significantly greater T-cell response than asymptomatic subjects, while antibody levels did not correlate with disease severity.

Notably, an additional 45 (2.0%) of PCR-negative participants tested positive with the T-Detect Assay for past SARS-CoV-2 infection. About half of these individuals had reported symptoms before or after PCR testing or a household exposure, indicating the T-cell assay may also identify past infections that had been missed by prior PCR testing.

About T-Detect
T-Detect is a highly sensitive and specific diagnostic test under development for multiple diseases, translating the natural diagnostic capability of T cells into clinical practice. In 2018, Adaptive and Microsoft partnered to build a map of the immune system called the TCR-Antigen Map. This approach uses immunosequencing, proprietary computational modeling, and machine learning to map T-cell receptor sequences to disease-associated antigens for infectious diseases, autoimmune disorders and cancer. From a simple blood draw, T-Detect will leverage the map to provide an immunostatus for an individual, enabling early disease diagnosis, disease monitoring, and critical insights into immunity. T-Detect COVID will be the first clinical test launched from this collaboration and the first commercially available T cell test designed to detect past SARS-CoV-2 infections. It is expected to launch this fall.