Adv Rheumatol. 2026 Jun 27. doi: 10.1186/s42358-026-00559-7. Online ahead of print.
ABSTRACT
BACKGROUND: Septic arthritis (SA) is a rapidly progressive joint disease that can lead to cartilage damage if not treated promptly. A prompt and accurate distinction between SA and inflammatory arthritis (IA) is essential for establishing an optimal treatment plan. Progranulin (PRGN), an anti-inflammatory glycoprotein involved in various autoimmune diseases, has rarely been studied as a diagnostic biomarker for infectious arthritis. However, its precise role in this context remains unclear. This study aimed to evaluate the diagnostic utility of synovial fluid PRGN (SF-PRGN) in distinguishing SA from IA and osteoarthritis (OA).
METHODS: This single-center, cross-sectional study included 59 patients who underwent synovial fluid aspiration and were categorized into three groups: SA (n = 23), IA (n = 18), and OA (n = 18). SA was diagnosed based on a positive synovial fluid culture or fulfillment of clinical criteria suggestive of infection. SF-PRGN levels were measured using ELISA, and synovial fluid C-reactive protein (SF-CRP) levels were determined using an immunoturbidimetric assay.
RESULTS: Mean SF-PRGN levels were higher in the SA (339.77 ± 142.16 ng/mL) and IA (300.52 ± 159.60 ng/mL) groups than in the OA group (133.44 ± 41.77 ng/mL), indicating a statistically significant difference between the inflammatory and non-inflammatory groups (p < 0.05). However, the SF-PRGN did not significantly differentiate between SA and IA (p = 0.803). In contrast, SF-CRP levels were markedly elevated in SA (61.91 ± 46.84 mg/L) and demonstrated strong discriminatory power between SA and IA (p < 0.001; AUC: 0.795, p < 0.0001).
CONCLUSION: Although SF-PRGN levels are elevated in inflammatory arthritis, they lack specificity for SA. SF-CRP exhibited superior diagnostic accuracy in differentiating SA from IA. These findings underscore the need for further research on reliable biomarkers of SA in larger patient cohorts.
CLINICAL TRIAL REGISTRATION: Clinical trial number not applicable.
PMID:42365362 | DOI:10.1186/s42358-026-00559-7
