Objectives: We explored the impact of circulating anti-N-methyl-D-aspartate receptor (NMDAR) antibodies on the severity of fatigue in patients with systemic lupus erythematosus (SLE).
Methods: Serum samples of 426 patients with SLE were analysed for the presence of antibodies to the NR2 subunit of the NMDAR. In parallel, the severity of fatigue was determined according to the Fatigue Scale for Motor and Cognitive functions questionnaire. In a subgroup of patients with SLE, the hippocampal volume was correlated with the levels of anti-NR2 antibodies. Isolated immunoglobulin G from patients with anti-NR2 antibodies were used for murine immunohistochemical experiments and functional assays on neuronal cell lines. Treatment effects were studied in 86 patients with lupus under belimumab therapy.
Results: We found a close correlation between the titre of anti-NR2 antibodies, the severity of fatigue, the clinical disease activity index (Systemic Lupus Erythematosus Disease Activity Index 2000) and anti-double stranded DNA antibodies-independently of the presence of neuropsychiatric lupus manifestations. Pathogenic effects could be demonstrated by (1) detection of anti-NR2 antibodies in the cerebrospinal fluid, (2) in situ binding of anti-NR2 antibodies to NMDAR of the hippocampus area and (3) distinct functional effects in vitro: downregulating the energy metabolism of neuronal cells without enhanced cytotoxicity. Treatment with belimumab for at least 6 months affected both the severity of fatigue and the levels of anti-NR2 antibodies.
Conclusion: The presence of anti-NR2 antibodies in patients with SLE with fatigue is a helpful diagnostic tool and may offer a major approach in the therapeutic management of this important disabling symptom in patients with SLE.
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http://dx.doi.org/10.1136/annrheumdis-2019-215098 | DOI Listing |
Int J Mol Sci
November 2023
Department of Neuroimmunology, The Cyprus Institute of Neurology and Genetics, Nicosia 2371, Cyprus.
Synaptic dysfunction and disrupted communication between neuronal and glial cells play an essential role in the underlying mechanisms of multiple sclerosis (MS). Earlier studies have revealed the importance of glutamate receptors, particularly the N-methyl-D-aspartate (NMDA) receptor, in excitotoxicity, leading to abnormal synaptic transmission and damage of neurons. Our study aimed to determine whether antibodies to the NR2 subunit of NMDAR are detected in MS patients and evaluate the correlation between antibody presence and clinical outcome.
View Article and Find Full Text PDFLupus Sci Med
November 2023
Rheumatology Unit, AOU Cagliari, Cagliari, Italy.
Objectives: To explore the effects of anti-ribosomal P protein (anti-P) and anti-N-methyl-D-aspartic acid receptor subunit 2 (anti-NR2) autoantibodies on depression and cognitive dysfunction and their relationships with functional brain connectivity in SLE.
Methods: This cross-sectional study included adult patients who fulfilled the American College of Rheumatology/European Alliance of Associations for Rheumatology 2019 SLE criteria. Anti-P and anti-NR2 were quantified using ELISA.
Front Immunol
July 2023
Rheumatology Unit, University Clinic, AOU Cagliari, Cagliari, Italy.
Introduction: The pathogenesis of neuropsychiatric systemic lupus erythematosus (NPSLE) is widely unknown, and the role of autoantibodies is still undetermined.
Methods: To identify brain-reactive autoantibodies possibly related to NPSLE, immunofluorescence (IF) and transmission electron microscopy (TEM) on rat and human brains were performed. ELISA was used to reveal the presence of known circulating autoantibodies, while western blot (WB) was applied to characterize potential unknown autoantigen(s).
Front Psychiatry
March 2023
Department of Internal Medicine, Division of Nephrology, University Medical Center of the Johannes Gutenberg University Mainz, Mainz, Germany.
As a chronic autoimmune disease systemic lupus erythematosus (SLE) can also affect the central and the peripheral nervous system causing symptoms which are summed up as neuropsychiatric systemic lupus erythematosus (NPSLE). These symptoms are heterogenous including cognitive impairment, seizures, and fatigue, leading to morbidity or even mortality. At present, little is known about the pathophysiological processes involved in NPSLE.
View Article and Find Full Text PDFInt J Mol Sci
February 2023
Center for Rheumatic Disease Rhineland-Palatinate, 55543 Bad Kreuznach, Germany.
Fatigue is a widespread and complex symptom with motor and cognitive components; it is diagnosed predominantly by questionnaire. We recently published a correlation between anti-N-methyl-D-aspartate receptor (NMDAR) antibodies and fatigue in patients with SLE (systemic lupus erythematosus). In the present study, we examined whether this association also applies to patients with other rheumatic diseases.
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