New research reported in the journal Nature could lead to new targeted treatments for rheumatoid arthritis (RA). The findings showed that guesswork could be taken out of selecting treatments for each patient, and this might one day also be extended to other autoimmune conditions.
The study was led by University of Colorado School of Medicine faculty members Fan Zhang, PhD, and Anna Helena Jonsson, MD, PhD. The Accelerating Medicines Partnership: Rheumatoid Arthritis and Systemic Lupus Erythematosus (AMP: RA/SLE) Network collected inflamed tissue from 70 patients with RA from across the country and the United Kingdom. Jonsson supervised the team of scientists who processed these samples for analysis, and Zhang led the computation analysis of the data. These efforts yielded a cell atlas encompassing more than 300 000 cells from synovial tissue. Further analysis revealed that there are six different subgroups of RA based on their cellular makeup.
“We hope the data will help us discover new treatment targets,” says Jonsson, assistant professor of rheumatology. “We wanted to make it public so that researchers across the country and across the world can continue working on new treatment ideas for rheumatoid arthritis going forward.”
No more guess-and-check
Jonsson, a practicing rheumatologist as well as a researcher, knows that RA patients respond differently to different treatments. Until now, she says, rheumatologists used a “guess and check” method to find a treatment that works for an individual patient.
With the new data and powerful computational classification methods developed by Zhang and the computational analysis team, the researchers were able to quantitatively classify RA types into what they call ‘cell-type abundance phenotypes’, or CTAPs. Developed methods, together with the new cell atlas, can start to identify which patients will respond to which treatments.
“Even when you classify rheumatoid arthritis inflammation using these simple markers – T cell markers, B cells, macrophages and other myeloid cells, fibroblasts, endothelial cells – what we found is that each of those categories is associated with very specific kinds of pathogenic cell types we’ve already discovered,” Jonsson says. “Previous rheumatoid arthritis research found that T cell populations called peripheral helper T cells are relevant in rheumatoid arthritis, as are B cells called antibody-producing B cells, and other specific cell types. What we found is that they’re usually not found all together.
“For example, the peripheral helper cells are found with the B cells in only one category of RA, and the pathogenic macrophage populations tend to exist in a different category. Because of this, we can start asking questions about how these specific partners work together.”
