Association of anti-NR2 and U1RNP antibodies with neurotoxic inflammatory mediators in cerebrospinal fluid from patients with neuropsychiatric systemic lupus erythematosus

Neuropsychiatric lupus erythematosus: Focusing on autoantibodies

Patients with systemic lupus erythematosus (SLE) frequently suffer from nervous system complications, termed neuropsychiatric lupus erythematosus (NPLE). NPLE accounts for the poor prognosis of SLE. Correct attribution of NP events to SLE is the primary principle in managing NPLE. The vascular injuries and neuroinflammation are the fundamental neuropathologic changes in NPLE. Specific autoantibody-mediated central nerve system (CNS) damages distinguish NPLE from other CNS disorders. Though the central antibodies in NPLE are generally thought to be raised from the periphery immune system, they may be produced in the meninges and choroid plexus. On this basis, abnormal activation of microglia and disease-associated microglia (DAM) should be the common mechanisms of NPLE and other CNS disturbances. Improved understanding of both characteristic and sharing features of NPLE might yield further options for managing this disease.

Formal neurocognitive function and anti-N-methyl-D-aspartate receptor antibodies in paediatric lupus

Objective

SLE is a chronic multisystem autoimmune inflammatory disease impacting a number of organs, including the central nervous system (CNS). The pathophysiology of CNS lupus is multifactorial, making diagnosis problematic. Neurocognitive (NC) testing and specific biomarkers to identify the development of neuropsychiatric (NP) symptoms in lupus are needed. Paediatric patients with SLE have high incidence of NP disease. While serum anti-N-methyl-D-aspartate receptor (NMDAR) antibodies have shown promise as a biomarker of NP in adults with SLE, much less is known with regard to paediatric patients with SLE.

Methods

We performed a cross-sectional study in paediatric patients with SLE. Serum NMDAR antibodies were measured and compared with levels in patients with juvenile idiopathic arthritis (JIA). Formal NC testing was performed in accordance with the Childhood Arthritis & Rheumatology Research Alliance neuropsychological core test battery. NC functioning was compared in the two groups and with NMDAR antibody levels.

Results

Serum NMDAR antibody levels were significantly higher in paediatric patients with SLE compared with patients with JIA. There were no significant correlations between NMDAR antibody levels and any measure of NC functioning. In an exploratory examination of anti-ribosomal P (RibP) antibody and NC functioning in a subset of patients with SLE, RibP antibody-positive patients exhibited worse scores for Verbal Memory Index and Design Fluency Test Switching compared with RibP antibody-negative patients. A globally significant association between disease status and NC functioning was observed. Specifically, patients with SLE had lower scores compared with patients with JIA for full-scale IQ, letter–word recognition, reading fluency and calculation skills after adjusting for multiple comparisons.

Conclusion

These collective results suggest that although serum NMDAR may serve as a biomarker, formal NC testing is superior in identifying paediatric patients with SLE with NP manifestations. RibP also may potentially serve as a biomarker of NP manifestations in paediatric patients with SLE. Additional and longitudinal studies are needed.