Migraine in patients with systemic lupus erythematosus is associated with reduced cerebral grey matter volume but not with measures of glial activation or anti-NR2 or anti-P antibodies.

BACKGROUND AND PURPOSE: Migraine is frequent in patients with systemic lupus erythematosus (SLE), but the pathogenesis and pathophysiology are poorly understood. Migraine is assumed to be a consequence of abnormal neuronal excitability. Based on the hypothesis that the threshold for migraine is lower in SLE patients due to cerebral disturbances, whether structural abnormalities of the brain or relevant biomarkers are associated with headaches in SLE was investigated. METHODS: Sixty-seven SLE patients and age- and gender-matched healthy subjects participated. Volumes of grey matter (GM) and white matter (WM) were estimated from cerebral magnetic resonance images with SPM8 software. Anti-NR2 and anti-P antibodies and protein S100B were measured in cerebrospinal fluid. RESULTS: In regression analyses, larger GM volumes in SLE patients reduced the odds for headache in general [odds ratio (OR) 0.98, P = 0.048] and for migraine in particular (OR 0.95, P = 0.004). No localized loss of GM was observed. Larger WM volumes in patients increased the odds for migraine (OR 1.04, P = 0.007). These findings could not be confirmed in healthy subjects. Neither anti-NR2 and anti-P antibodies nor S100B were associated with headaches in SLE patients. CONCLUSIONS: Systemic lupus erythematosus patients with migraine have a diffuse reduction in GM compared to patients without migraine. This finding was not observed in healthy subjects with migraine, and selected biomarkers did not indicate specific pathophysiological processes in the brain. These findings indicate that unknown pathogenic processes are responsible for the increased frequency of migraine in SLE patients.

Transverse myelitis extended to disseminated encephalitis in systemic lupus erythematosus: Histological evidence for vasculitis.

A 42-year-old woman was admitted due to systemic lupus erythematosus complicated with glomerulonephritis and pulmonary hypertension. During the treatment for these complications, she presented motor paresis and sensory loss caused by transverse myelitis. In spite of methyl prednisolone pulse therapy, she further developed acute confusional state due to disseminated encephalitis and fell into respiratory arrest. On laboratory examination, elevation of anti-NR2 antibodies in serum as well as in cerebrospinal fluid was noted. Although she recovered from the disseminated encephalitis after extensive treatment with high doses of corticosteroid and intravenous cyclophosphamide, she suddenly died of pulmonary hypertension. Autopsy findings confirmed the presence of liquefaction necrosis in the entire circumference of the whole spinal cord along with intimal hyperplasia and obliteration of the small arteries, accompanied by mononuclear cell infiltration and disruption of internal elastic lamina. It is therefore most likely that our patient developed longitudinal transverse myelitis through spinal cord vasculitis, which extended to brainstem and brain parenchyma, leading to the development of disseminated encephalitis.

Neurofilament light is a biomarker of brain involvement in lupus and primary Sjögren's syndrome.

BACKGROUND: To test the hypothesis that neurofilament light (NfL) in CSF is a biomarker of CNS involvement in patients with systemic lupus erythematosus (SLE) and primary Sjögren's syndrome (pSS), we measured NfL in CSF from 52 patients with lupus and 54 with pSS and explored associations with clinical, structural, immunological and biochemical abnormalities. METHODS: In CSF, we measured NfL, anti-P antibodies, protein S100B and TWEAK by ELISA and anti-NR2 antibodies by electrochemiluminescence. Anti-phospholipid antibodies and routine immunological tests were performed in blood. IgG and albumin were measured in CSF and serum for assessment of the blood-brain barrier function (Q-albumin) and intrathecal IgG production (IgG index). Cerebral MRI and neuropsychological testing were performed. RESULTS: A multivariable regression model showed that increasing CSF anti-NR2 antibody levels were associated with increasing NfL levels in patients with SLE (B 1.27, 95% CI 0.88-1.65, p < 0.001). Age contributed significantly in the model (B 0.04, 95% CI 0.03-0.05, p < 0.001). Similar findings were observed in the pSS group. Adjusted for age and sex, no associations were found between NfL levels and any MRI data. In SLE patients, higher NfL concentrations were associated with impairments in psychomotor speed and motor function, and in pSS with motor dysfunction. These associations remained in multivariable regression models. CONCLUSIONS: Increased concentration of NfL in CSF is a marker of cerebral involvement in patients with SLE and pSS, is strongly associated with the presence of anti-NR2 antibodies, and correlates with cognitive impairment in several domains.

Anti-NR2 glutamate receptor antibodies as an early biomarker of cerebral small vessel disease.

OBJECTIVES: Cerebral small vessel disease (SVD) associated with age and vascular risk factors is one of the leading causes of cognitive disorders as well as ischemic and hemorrhagic strokes. The pathogenesis of this disease has not been fully understood yet. The previously established association of the antibodies against the NR2 subunit of the NMDA receptor (NR2ab) with the mechanisms of SVD such as ischemia and blood-brain barrier (BBB) disruption, might suggest their importance in the brain damage. DESIGN & METHODS: We studied the NR2ab serum level in 70 patients (45 females, 61.1 ± 6.3 y.o.) with different severity of cognitive impairment and MRI features of SVD and 20 healthy volunteers (12 females, 58.5 ± 6.4 y.o.). RESULTS: The elevated level of NR2ab was associated with subjective cognitive impairment (SCI) (p = 0.028) and mild cognitive impairment (MCI) (p = 0.017), Fazekas grade (F) 2 (p = 0,002) and F3 (p = 0,009) of white matter hyperintensities (WMH) and the numbers of lacunes in the cerebral white matter (less than 5) (p = 0,039). CONCLUSION: The detected increase in serum NR2ab level in patients with SCI, as well as the minimal amount of white matter lacunes, is most likely caused by hypoxia-induced endothelial damage in the early stage of SVD. Normal NR2ab values in patients with F1 WMH, the increased NR2ab level in patients with F2 and F3 WMH and those with the minimal number of lacunes can indicate that NR2bs are involved in diffuse brain damage due to hypoxia-induced loss of BBB integrity.

Clinical significance of anti-DNA/N-methyl-D-aspartate receptor 2 antibodies in de novo and post-steroid cases with neuropsychiatric systemic lupus erythematosus.

BACKGROUND: Anti-DNA/N-methyl-D-aspartate receptor 2 (NR2) antibodies (anti-DNA/NR2 antibodies) are a subset of anti-DNA autoantibodies that cross-react with the extracellular domain of the GluN2A/GluN2B subunits of NR2. These antibodies induce apoptosis of hippocampus neurons and psychiatric disorder in mice and humans. Neuropsychiatric system lupus erythematosus (NPSLE) can develop after initiation of corticosteroids (post-steroid neuropsychiatric manifestation: PSNP) or before treatment (de novo NPSLE); however, pathophysiological differences between these subtypes remain unclear. The objective of this study was to clarify the prevalence of anti-DNA/NR2 antibodies in patients with NPSLE. METHODS: This study involved a cohort of patients with NPSLE admitted to our hospital. NPSLE patients were classified into two groups, de novo NPSLE and PSNP-SLE. Serum anti-DNA antibodies and anti-DNA/NR2 antibodies were measured by enzyme-linked immunosorbent assays. RESULTS: Serum samples were obtained from 24 patients with de novo NPSLE, 25 with PSNP-SLE and 76 healthy controls (HC). The level of anti-DNA/NR2 antibodies in patients with de novo NPSLE and PSNP-SLE were also higher than those in HC. Positive correlation between anti-DNA antibodies and anti-DNA/NR2 antibodies were found in PSNP-SLE, but was not significant in de novo NPSLE. CONCLUSION: The levels of anti-DNA/NR2 antibodies in PSNP-SLE were similar to those in de novo NPSLE. Anti-DNA/NR2 antibodies in PSNP-SLE were suggested as a dominant subset of anti-DNA antibodies, indicating that anti-DNA/NR2 antibodies may be a predictive factor in PSNP-SLE.

Anti-NR2 antibodies, blood-brain barrier, and cognitive dysfunction.

Cognitive dysfunction (CD) is one of the most common neuropsychiatric manifestations of systemic lupus erythematosus (SLE). In animal models, antibodies to NR2 subunit of N-methyl D-aspartate receptor (anti-NR2) cause memory impairment, but only with blood-brain barrier (BBB) disruption or intrathecal administration. Several studies have failed to find association of aNR2 with CD, but none have assessed BBB integrity. S100B, an astrocyte-specific protein, has been used as biomarker of BBB disruption in traumatic brain injury and some neurodegenerative disorders. Antibodies to this immunologically privileged protein (anti-S100B) might indicate preceding BBB disruption. We hypothesized that aNR2 antibody is pathogenic in SLE patients only with BBB disruption. Demographic, clinical, and laboratory data was collected from patients with SLE. Total throughput score (TTS) of the Automated Neuropsychological Assessment Metrics (ANAM) was used as primary outcome measure. CD was defined as TTS < 1.5 SD below an age-, sex-, and race-matched RA population mean. Serum was analyzed by established ELISA techniques. Fifty-seven patients were evaluated and 12 had CD. Age, ethnicity, and family income were significantly different between the two groups (p < 0.05). In a multiple regression model adjusting for other variables, no significant effects of anti-NR2, S100B, or anti-S100B on TTS were found. Even at high levels of S100B and anti-S100B, no significant influence of anti-NR2 on TTS was found. The anti-NR2 was not associated with CD in SLE even in context of potential BBB disruption. This suggests that, if pathogenic, these antibodies may be produced intrathecally.