Performance of a commercially available multiplex platform in the assessment of circulating cytokines and chemokines in patients with rheumatoid arthritis and osteoarthritis

Background/objective: Cytokines and chemokines (cytokines) are central to rheumatoid arthritis (RA) pathogenesis, with increasing use of multiplex immunoassays in clinical/research settings. Rheumatoid factor (RF) may interfere with assay outcomes by nonspecifically binding detection analytes. We evaluated the performance of a commercially available multiplex platform, including assessment of the impact of RF depletion. Methods: Forty-five cytokines were tested using Meso Scale Discovery V-PLEX™ and samples from 40 RA and 40 osteoarthritis (OA) patients. Select samples were depleted of RF using a commercial binder. Performance was assessed using intra-assay coefficients of variation (CV), intraclass correlation coefficients (ICC), percent change following RF depletion, and disease discrimination. Values above or below quantification thresholds were imputed. Results: Of the 45 cytokines analyzed, 31 yielded CVs <10%; none demonstrated CVs >30%. ICCs universally exceeded 0.85 with the exception of eight analytes. RF depletion altered cytokine values by <15% for 40 analytes with larger changes (>30%) only seen for one analyte. Twenty-three cytokines differed significantly based on measurement in plasma vs. serum. Three analytes were higher in the serum of RA vs. OA (IL-10, IP-10, TNFα), and none were significantly greater in OA vs. RA. Seventeen analytes required imputation for >50% of the samples tested, primarily related to concentrations below the lower limit of quantification threshold. Conclusion: The results from this commercially available multiplex assay were generally highly reproducible and interference induced by RF only meaningfully impacted the quantification of five of the analytes examined.