Biomarkers Help Differentiate Between Psoriatic Arthritis, Rheumatoid Arthritis

A serum biomarker panel can distinguish between patients with early psoriatic arthritis (PsA) and patients with rheumatoid arthritis (RA), according to the results of a recent study.

To overcome the challenge of diagnosing PsA and enable early intervention in these patients, a research team in Ireland and Holland conducted a study to identify protein biomarkers in serum that could distinguish between patients with early PsA and patients with RA.

To investigate the serum proteome of patients with PsA or RA, the researchers used (1) nano-flow liquid chromatography mass spectrometry, (2) an aptamer-based assay (SOMAscan) that targeted more than 1000 proteins, and (3) a multiplexed antibody assay for 48 proteins. Next, they developed multiple reaction monitoring assays to assess the usefulness of potential biomarkers within a discovery cohort of 60 patients and then within an independent cohort of 167 patients with PsA or RA.

After performing multivariate machine learning analyses of the data obtained by using each of the 3 methods, the researchers determined that patients with PsA could be distinguished from patients with RA with an area under the curve of 0.94 for nano-flow liquid chromatography mass spectrometry, 0.73 for the SOMAscan, and 0.69 for the multiplexed antibody assay.

In separate studies conducted to verify and evaluate these results, a random forest model showed that a subset of proteins measured by multiple reaction monitoring assays were capable of distinguishing between patients with PsA and patients with RA.

“With continued evaluation and refinements using additional and larger patient cohorts including those with other arthropathies we suggest the panel identified here could contribute toward improved clinical decision making,” the researchers concluded.

—Ellen Kurek


Mc Ardle A, Kwasnik A, Szenpetery A, et al. Identification and evaluation of serum protein biomarkers that differentiate psoriatic arthritis from rheumatoid arthritis. Arthritis Rheumatol. 2022;74(1):81-91.