Serum Slit3 is associated with disease activity and interstitial lung disease in rheumatoid arthritis

Rheumatoid arthritis (RA) is a chronic systemic inflammatory disease accompanied by high incidence rate of interstitial lung disease (ILD). Slit guidance ligand 3 (Slit3) which is a member of axon guidance molecule superfamily, mediates a series of biological activities. In this study, we explored the potential clinical significance of Slit3, especially as a serum biomarker for evaluating RA-ILD. Patients diagnosed with RA were recruited between July 2022 to April 2024 from the Department of Rheumatology of Foshan First Peoples Hospital. The clinical data were collected from hospital records, serum level of Slit3 was detected by enzyme-linked immunosorbent assay (ELISA). Among 232 recruited patients, RA patients in high Slit3 subgroup were older, showed higher proportion of positive rheumatoid factor (RF) status and anti-cyclic citrullinated peptide antibody (APCA) status, as well as higher levels of ESR, CRP, Disease Activity Score in 28 joints with four variables, including C-reactive protein (DAS28-CRP) or erythrocyte sedimentation rate (DAS28-ESR), Simplified Disease Activity Index (SDAI) and pro-inflammatory cytokine interleukin-6 (IL-6). Notably, Logistic regression analysis showed that elevated serum Slit3 was an independent relevant factor of RA-ILD (OR 1.005 [95% CI 1.002-1.008], P=0.002). Our findings evealed that serum Slit3 was associated with disease activity in RA and may hold promise as a useful serum biomarker and therapeutic target for RA-ILD.