Objective:

To evaluate the diagnostic accuracy of cerebrospinal fluid antisuprabasin antibody for identifying neuropsychiatric systemic lupus erythematosus (NPSLE) among patients with SLE presenting with neuropsychiatric symptoms.

Approach:

• Study Design: A single-center prospective consecutive diagnostic cohort study was conducted at Renji Hospital in Shanghai, China, from January 2022 to October 2025, involving 190 patients with SLE.
• Patient Selection: 148 patients who met the 2019 European League Against Rheumatism/American College of Rheumatology classification criteria for SLE underwent lumbar puncture.
• Diagnosis Adjudication: An independent committee of specialists adjudicated final diagnoses using serologic and cerebrospinal fluid testing, neuroimaging, treatment records, and follow-up.
• Diagnostic Analysis: The study compared CSF antisuprabasin antibody concentrations among patients with NPSLE, CNS infection, and other causes.

Key Findings:

• CSF antisuprabasin antibody had an area under the receiver operating characteristic curve of 0.830 for identifying NPSLE, compared to 0.743 for CSF white blood cell count and 0.665 for serum antiribosomal P antibody.
• At an optimal cutoff of 76.36 ng/mL, CSF antisuprabasin antibody demonstrated 81% sensitivity and 74% specificity.
• Combining CSF antisuprabasin antibody with CSF white blood cell count and serum antiribosomal P antibody improved the area under the curve to 0.892.

Limitations:

• Single-center design and limited cohort size may restrict generalizability.
• Biomarker sampling was limited to the emergency setting.
• The posttreatment trajectory of CSF antisuprabasin antibody remains unknown.
• The paired analysis of 42 patients lacked sufficient power to establish the biological origin of CSF antisuprabasin antibody.

Conclusion:

Multicenter longitudinal studies are needed to validate the diagnostic threshold and evaluate biomarker changes over time.

Sources:

• Lupus Science & Medicine