A new “extreme” sensitivity test developed at the Alicante General Hospital based on CSIC technology is capable of detecting antibodies against COVID-19 so far invisible in patients who have overcome the virus and who, apparently, had not generated any immunity.
Starting with a fingerstick, the innovative test has been designed by Hematology and Immunology researchers from the Alicante hospital center Fabián Tarín (Valencia, 54 years old), Francisco Marco (Elche, Alicante, 57) and Paula Piñero (Seville, 30) as part of the Alicante Health and Biomedical Research Institute (Isabial).
This advance, published in the prestigious journal ‘Scientific Reports’, has had the collaboration of the company Vitro Diagnóstica and the Incliva Health Research Institute.
“To date we were aware that a minority percentage of people with proven infection (around 5%), especially mild, asymptomatic or immunosuppressed, they didn’t seem to develop antibodies and they probably remained unprotected in the event of a possible reinfection, “Tarín told Efe.
This technique, more sensitive than conventional ones, reveals that “almost half of these patients have antibodies in small amounts, invisible to other techniques, and therefore could have some protection against SARS-CoV-2 “, he continued.
Therefore, the detection of these low rates of antibodies that are undetectable in other tests provides valuable information for medical strategy of these patients who, in fact, could be protected in case of being infected again.
The test visualizes an “essential” type of antibody
The work of Tarín, Marco and Piñero is based on genetically engineered cell lines in the CSIC laboratories and is based on a test known as flow cytometry that only requires one microliter of blood taken from the finger.
Francisco Marco, member of the Spanish Immunology Society, stressed that the test visualizes an “essential” type of antibody, IgA type, which remains for up to eight months after infection in the vast majority of patients and that constitutes the first barrier against the virus. This is so because it is located in mucous membranes such as saliva or breast milk, where it is capable of blocking germs to prevent infection.
The scientist has warned, in any case, that “we must not lower our guard” since the presence of the antibodies “does not guarantee the individual an indefinite protection” against the virus and its new variants. Even considering these precautions, Paula Piñero has assured that the first results obtained so far in vaccinated patients “indicate that the patients inoculated with the different vaccines present a vigorous response.”
Especially useful for investigating the protection of immunosuppressed or cancer patients
The greater ability to detect antibodies by the test could be especially useful for investigating the degree of protection in immunosuppressed or cancer patients, which theoretically develop weaker immune responses, being more unprotected and exposed to serious forms of infection.
The Diagnostic Hematology and Immunology sections of the General Hospital of Alicante, to which the three authors of the study belong, are immersed in ambitious research projects linked to the immunity of patients with different hematological diseases.