Orange DE, et al. - Researchers sought to determine the proportion of patients with rheumatoid arthritis (RA) in remission or with low disease activity at the time of arthroplasty who had histologic or transcriptional evidence of synovitis. In addition, they sought for the clinical features that differentiated patients as having subclinical synovitis among 135 patients with RA undergoing arthroplasty. Results revealed low clinical disease activity with histologic evidence of subclinical synovitis in 31% of patients, which was associated with increased C-reactive protein and increased anti–cyclic citrullinated peptide antibody levels. The synovium of patients with subclinical synovitis differentially expressed 183 genes compared to patients with a “low inflammatory synovium” subtype. The synovium of patients with the clinically active disease also differentially expressed the majority of these genes (86%).