Myeloid-related protein 8/14 in plasma and serum in patients with new-onset juvenile idiopathic arthritis in real-world setting in a single center

• Main Authors: Paula L. Keskitalo (Author), Salla M. Kangas (Author), Sirja Sard (Author), Tytti Pokka (Author), Virpi Glumoff (Author), Petri Kulmala (Author), Paula Vähäsalo (Author)
• Format: Book
• Published: BMC, 2022-06-01T00:00:00Z.
• Subjects: article
• Online Access: Connect to this object online.
• Notes: 10.1186/s12969-022-00701-x; 1546-0096
• Keywords: Biomarker; Calprotectin; Juvenile idiopathic arthritis; S100A8/A9; MRP8/14; Pediatrics; RJ1-570; Diseases of the musculoskeletal system; RC925-935
• Source: Pediatric Rheumatology Online Journal, Vol 20, Iss 1, Pp 1-9 (2022)

Abstract Objective The aim of this study was to analyze the usefulness of myeloid-related protein 8/14 (MRP8/14) in the prediction of disease course in a real-world setting for patients with new-onset juvenile idiopathic arthritis (JIA), to identify the relationship between MRP8/14 and disease activity using the physician's global assessment of disease activity (PGA), and determine whether the MRP8/14 levels measured in serum and plasma are equally useful. Methods In this prospective follow-up study, 87 new-onset non-systemic JIA patients were studied. Blood and synovial fluid samples were collected prior to any antirheumatic medication use. MRP8/14 was measured from serum (S-MRP8/14), plasma (P-MRP8/14), and synovial fluid samples using ELISA. Results The baseline MRP8/14 blood levels were significantly higher in patients using synthetic antirheumatic drugs than in patients with no systemic medications at 1 year after diagnosis in serum (mean 298 vs. 198 ng/ml, P < 0.001) and in plasma (mean 291 vs. 137 ng/ml, P = 0.001). MRP8/14 levels at the time of JIA diagnosis were higher in patients who started methotrexate during 1.5-year follow-up compared to those who achieved long-lasting inactive disease status without systemic medications (serum: mean 298 vs. 219 ng/ml, P = 0.006 and plasma: 296 vs. 141 ng/ml, P = 0.001). P-MRP8/14 was the most effective predictive variable for disease activity (by PGA) in linear multivariate regression model (combined to ESR, CRP, leukocytes, and neutrophils), whereas S-MRP8/14 was not significant. Conclusion Blood MRP8/14 levels at baseline seem to predict disease course in new-onset JIA patients. P-MRP8/14 might be better than S-MRP8/14 when assessing disease activity at the time of JIA diagnosis.