Key clinical point: A newly identified cell type may be predictive of RA flares.

Major finding: Preinflammatory mesenchymal cells were expanded in the week preceding a flare and decreased during the flare.

Study details: A longitudinal, observational study of 23 patients with RA.

Disclosures: The study was supported by grants from the National Institutes of Health, Simons Foundation, Robertson Foundation, Rheumatology Research Foundation, Bernard and Irene Schwartz Foundation, the Iris and Junming Le Foundation, and Rockefeller University. Dr. Orange disclosed a provisional patent for the discovery of the preinflammatory mesenchymal cells.

Commentary

“RA is characterized by periods of increased disease activity, or flare, and remission, but our understanding of what triggers flares and how to predict them is incomplete. This study combines serial assessment of transcriptional signatures in the blood with patient-reported disease activity measurements to determine gene transcriptional activity preceding flares. It is innovative in its use of a large amount of gene signature data from relatively small set of patients, and further identified a subtype of fibroblast-like cells, named by the authors as “pre-inflammatory mesenchymal cells” that appear in peripheral blood before RA flares and decrease during the flare, suggesting that they may move to the joints and trigger inflammation.

The small group of patients does limit generalizability at this point and background medications were not considered. However, the study provides a foundation for further investigation into the function and eventual destination of these cells, as well as their involvement in systemic inflammation such as cytokine production and antigen presentation.”

Arundathi Jayatilleke, MD

Lewis Katz School of Medicine, Temple University