A group of researchers from the Instituto de Medicina Molecular (iMM) Lisbon discovered that a specific type of regulatory cells in human blood, follicular regulatory T cells, are formed whenever there is antibody production, increasing transiently after vaccination and being persistently increased in people with Sjögren's Syndrome, an autoimmune disease characterized by abnormal antibody production.
The team, led by researcher Luís Graça, discovered that the blood follicular regulatory T cells are a marker of immune responses where antibodies are produced.
At the same time, and contrary to what was previously thought, these results published now in the journal Science Immunology reveal that these cells in human blood are not a direct indicator of the ability to regulate the production of antibodies, as they are still in an immature state.
To understand the true meaning of the presence of follicular regulatory T cells in human blood, the team developed several strategies that allowed them to directly study different human tissues: blood, thymus, tonsils and umbilical cord blood.
In addition, the researchers also studied blood from people who had been vaccinated against the flu virus and from people with genetic deficiencies that affect the immune system.
The researchers thus realized that the pre-established idea that follicular regulatory T cells in the blood have the ability to stop the production of abnormal antibodies runs counter to the observation that patients with Sjögren's Syndrome have more of these same cells in circulation.
In fact, the ability to regulate the production of antibodies by parts of these cells is specific to those that exist in tissues, such as lymph nodes or tonsils.
The group is now investigating what happens to these cells in other autoimmune diseases to assess their potential not only for diagnosis, but also to identify which patients might benefit from drugs that interfere with the production of harmful antibodies.
Caption of the image above: Follicular regulatory T cells control the production of antibodies in the germinal centers of lymphatic organs
Author: Communication Office – Institute of Molecular Medicine (iMM)
Science in the Regional Press – Ciência Viva
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