Lupus Sci Med. 2026 Aug 6;13(2):e002144. doi: 10.1136/lupus-2026-002144.
ABSTRACT
BACKGROUND: Diagnostic attribution of neuropsychiatric symptoms in SLE (NPSLE) remains challenging. This study evaluated whether cerebrospinal fluid (CSF) antisuprabasin (SBSN) antibody can serve as a diagnostic biomarker for NPSLE.
METHODS: In this single-centre, prospective cohort study, patients with SLE presenting with new-onset neuropsychiatric or neurological symptoms were screened between January 2022 and October 2025. Final diagnoses were adjudicated by an independent committee blinded to CSF anti-SBSN antibody results. Patients were classified as NPSLE, SLE with central nervous system infection (SLE-CNSI) or SLE without NPSLE or CNS infection (SLE-Other). CSF anti-SBSN antibody levels were measured by ELISA. Diagnostic performance was assessed for identifying NPSLE against a combined non-NPSLE comparator group comprising SLE-CNSI and SLE-Other.
RESULTS: Among 190 screened patients, 148 were included in the final analysis, including 48 with NPSLE, 59 with SLE-CNSI and 41 with SLE-Other. CSF anti-SBSN antibody levels showed a stepwise increase across groups, with median concentrations of 47.60 ng/mL in SLE-Other, 72.82 ng/mL in SLE-CNSI and 88.94 ng/mL in NPSLE; all pairwise comparisons were significant (all p<0.001). For identifying NPSLE versus non-NPSLE comparators, CSF anti-SBSN antibody achieved an area under the receiver operating characteristic curve (AUROC) of 0.830, with a sensitivity of 0.812 and specificity of 0.740 at the optimal cut-off of 76.36 ng/mL. CSF anti-SBSN antibody had a higher AUROC than CSF white blood cell count (0.830 vs 0.743; p=0.041) and serum antiribosomal P antibody (0.830 vs 0.665; p=0.003). The three-marker model further increased the AUROC to 0.892 and significantly outperformed CSF anti-SBSN antibody alone (p=0.009).
CONCLUSION: CSF anti-SBSN antibody was significantly elevated in NPSLE and demonstrated good diagnostic performance for identifying NPSLE among patients with SLE presenting with neuropsychiatric symptoms. These findings support CSF anti-SBSN as a promising candidate diagnostic biomarker for NPSLE, particularly when combined with conventional CSF inflammatory and serological markers.
PMID:42562427 | DOI:10.1136/lupus-2026-002144