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Synovial Biopsy in Rheumatoid Arthritis: The Next Big Thing?

Synovial Biopsy in Rheumatoid Arthritis: The Next Big Thing?

Synovial fluid aspirates, biomarkers in blood, serologic testing, radiography, and ultrasonography have all been used to assist in the diagnosis and management of rheumatoid arthritis (RA). Most recently, management of RA in both early and later stages has been guided by peripheral blood assays combining several specific markers, interleukins, and inflammatory cytokines—unfortunately these have not been fruitful. For those of us who follow patients with RA, maintaining low disease activity or remission is challenging.

In the last few years, there has been a resurgence of interest in synovial tissue as a guide to managing RA. Interest in biopsies has grown due to the significant cost of biologics, the fact that between 20% and 40% of patients in clinical trials never achieve even a 20% response rate, and that there can be a 3- to 4-month delay between initiation and response to treatment. Algorithms for selection of a disease-modifying antirheumatic drug (DMARD) are most often American College of Rheumatology guideline-based with tiered recommendations. However, the guidelines do not necessarily address an individual's disease. Therefore, assessment with reliable biopsy results seems logical and may be an important step forward.

Using ultrasound guidance and the dorsal wrist as the preferred site, Mandelin and colleagues demonstrated that synovial macrophages appear to be a biologically relevant marker that can be used to gauge the activity of RA. A consortium of rheumatology practices in six US centers came together in this study with the purpose of standardizing the biopsy procedure, ensuring safety, and analyzing the synovium in a consistent fashion, with the hope of gaining insight into disease drivers. The patient numbers were small, but the authors were optimistic. They suggested that transcriptional signals in the biopsy sample would predict responsiveness to conventional DMARDs and biologic therapies. Should this procedure be standardized and proven to be accurate, it could become an important next step in the management of RA.

References
  • Mandelin AM, et al. Transcriptional profiling of synovial macrophages using minimally invasive ultrasound-guided synovial biopsies in rheumatoid arthritis. Arthritis Rheumatol. 2018;70:841-854.
  • Singh JA, et al. 2015 American College of Rheumatology guideline for the treatment of rheumatoid arthritis. Arthritis Rheumatol. 2016;68:1-26.

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Filed under: Rheumatology

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