Fibrinogen-like protein 1 as a novel biomarker of rheumatoid arthritis and diagnostic basis for disease activity: a diagnostic test study.

BACKGROUND

Early, accurate diagnosis of Rheumatoid Arthritis (RA) is essential for timely intervention, yet a simple and precise method for assessing disease activity remains a challenge. Biomarkers offer a promising solution for disease prediction and monitoring. Consequently, the discovery of novel biomarkers for RA diagnosis and disease activity evaluation is imperative.

OBJECTIVE

This study seeks to elucidate the diagnostic utility of fibrinogen-like protein 1 (FGL1, also referred to as HFREP1) in rheumatoid arthritis.

METHODS

A total of 237 RA patients and 236 non-RA control subjects were enrolled in this clinical trial. Serum levels of rheumatoid factor (RF), anti-cyclic citrullinated peptide (CCP) antibodies, erythrocyte sedimentation rate (ESR), and C-reactive protein (CRP) were measured and compared against HFREP1 concentrations quantified via enzyme-linked immunosorbent assay (ELISA).

RESULTS

Consistent with the established diagnostic gold standard, HFREP1 demonstrated higher sensitivity and negative predictive value compared to CRP and ESR. The area under the receiver operating characteristic curve (AUC) for HFREP1 was comparable to those of CRP and ESR. The combination of HFREP1, CCP antibody, and ESR yielded an AUC of 0.987, which indicates that HFREP1 does not enhance the diagnostic accuracy of the combination of CCP antibody and ESR. The mean serum concentration of HFREP1 was 71.87 ng/mL in patients with remission or low disease activity, compared to 175.47 ng/mL in those with moderate to high disease activity.

CONCLUSION

HFREP1 demonstrates diagnostic potential for RA and the capability to assess disease activity. It has greater sensitivity than CRP and ESR and can better evaluate disease activity than RF and CCP. These findings support the potential use of HFREP1 as a diagnostic marker for the diagnosis and assessment of RA. This trial is registered with the Chinese Clinical Trial Registry (Registration No.: ChiCTR2400082686; Date: 2024/04/03).