Identification of protein biomarkers in cerebrospinal fluid(CSF) of Neuro Psychiatric SLE(NPSLE) patients using SOMA scan assay.

Abstract

Abstract Background Neurological manifestations of systemic lupus erythematosus (NPSLE) include a wide spectrum of symptoms like seizures, meningitis and psychosis. Clinical diagnosis of NPSLE is challenging due to the lack of objective diagnostic tests. Here, we explore if CSF proteins may have diagnostic value in NPSLE. Methods 24 CSF samples (8 healthy + 8 neuro controls (NC) + 8 NPSLE) were screened using an aptamer-based platform for about 1100 proteins. A subset of the differentially expressed CSF proteins was selected for validation in two different cohorts, Caucasian controls (N=54) & NPSLE (N= 25) and Chinese controls (N=15) & SLE (N= 17). Results The initial aptamer-based screen revealed 8 CSF proteins to be elevated in NPSLE vs healthy, at fold change >2, and p <0.05. All 8 proteins were validated by ELISA. Total IgM, Lipocalin 2, M-CSF were significantly elevated in the CSF of NPSLE when compared to controls, in both Caucasian and Chinese patients (range of fold change: 16–1.2; p < 0.05). CSF HCC-s, DAN and Angiostatin were significantly elevated in Caucasian NPSLE patients only (range of fold change: 2.3–1.8; p < 0.05). Total C3 and albumin in CSF did not show any difference in disease groups in both cohorts, as assayed by ELISA. Conclusion Several novel proteins were noted to be elevated in NPSLE CSF, relative to control subjects with other neurological symptoms. Further studies are warranted to establish the specificity of CSF IgM, Lipocalin 2, M-CSF, HCC-s, DAN and Angiostatin for NPSLE and to understand their pathogenic relevance.