Study Finds New Subset of T Cells That Drive Inflammation in Peripheral Tissues

Researchers at Brigham and Women’s Hospital have discovered a subset of T cells that collaborate with other immune cells to drive inflammation in peripheral tissues. The cells were found in cell samples taken from patients with rheumatoid arthritis (RA) during a study that aimed to answer which T-cell subtypes help orchestrate the damaging immune responses that underlie RA.

In the study, the researchers took a disease-deconstruction approach, relying on “sophisticated technologies, such as mass cytometry, which allowed them to rapidly sift through blood, joint tissue and fluid surrounding joints to isolate specific cells defined by the assortment of molecules on their surfaces.” They also “harnessed RNA sequencing methods that can characterize even very small numbers of cells and reveal which genes are turned off.” With the use of these tools, the researchers homed in on a unique population of T cells, a type of CD4+ or helper T cell, that are highly prevalent (accounting for roughly one-quarter) in the joints of RA patients. In addition to their abundance, they found that the T cells are programmed to infiltrate parts of the body that are inflamed, where they stimulate B cells to produce antibodies. However, as is known with autoimmune diseases like RA, so-called autoantibodies instead recognize normal components of the human body and contribute to tissue damage. This study was the first detailed description of a type of T cell with these features.

Now, the researchers will seek to understand the signals that coax these cells to develop, and whether they play other roles in autoimmune diseases such as lupus, multiple sclerosis and type 1 diabetes. They will also explore whether targeting these cells could provide a treatment for RA.