Kitagori K, et al. - Investigators assessed the efficacy of osteopontin (OPN) in cerebrospinal fluid (CSF) as a diagnostic marker for neuropsychiatric systemic lupus erythematosus (NPSLE). They recorded elevated whole protein of osteopontin (OPN full) and its cleaved form (OPN N-half) in lupus nephritis (LN). They calculated the concentrations of OPN full and OPN N-half in CSF among NPSLE and non-NPSLE individuals. They observed a significant elevation in the concentration of OPN full in the CSF in NPSLE vs non-NPSLE; it also declined following treatment. They noticed the sensitivity and specificity for the diagnosis of NPSLE were 70%, and 100%, respectively when the cutoff value of OPN full in CSF was set to 963.4 ng/ml.