The neurology of lupus

Combining multimodal magnetic resonance brain imaging and machine learning to unravel neurocognitive function in non-neuropsychiatric systemic lupus erythematosus

OBJECTIVE

To study whether multimodal brain MRI comprising permeability and perfusion measures coupled with machine learning can predict neurocognitive function in young patients with SLE without neuropsychiatric manifestations.

METHODS

SLE patients and healthy controls (HCs) (≤40 years of age) underwent multimodal structural brain MRI that comprised voxel-based morphometry (VBM), magnetization transfer ratio (MTR) and dynamic contrast-enhanced (DCE) MRI in this cross-sectional study. Neurocognitive function assessed by Automated Neuropsychological Assessment Metrics was reported as the total throughput score (TTS). Olfactory function was assessed. A machine learning-based model (i.e. glmnet) was constructed to predict TTS.

RESULTS

Thirty SLE patients and 10 HCs were studied. Both groups had comparable VBM, MTR, olfactory bulb volume (OBV), olfactory function and TTS. While after correction for multiple comparisons the uncorrected increase in the blood-brain barrier (BBB) permeability parameters compared with HCs did not remain evident in SLE patients, DCE-MRI perfusion parameters, notably an increase in right amygdala perfusion, was positively correlated with TTS in SLE patients (r = 0.636, false discovery rate P < 0.05). A machine learning-trained multimodal MRI model comprising alterations of VBM, MTR, OBV and DCE-MRI parameters mainly in the limbic system regions predicted TTS in SLE patients (r = 0.644, P < 0.0005).

CONCLUSION

Multimodal brain MRI demonstrated increased right amygdala perfusion that was associated with better neurocognitive performance in young SLE patients without statistically significant BBB leakage and microstructural abnormalities. A machine learning-constructed multimodal model comprising microstructural, perfusion and permeability parameters accurately predicted neurocognitive performance in SLE patients.

Neuropsychiatric lupus in late- and early-onset systemic lupus erythematosus patients: a systematic review and meta-analysis

OBJECTIVES

Late-onset SLE is usually milder and associated with lower frequency of LN and neuropsychiatric manifestations. The diagnosis of NPSLE is especially challenging in older patients because of increased incidence of neurological comorbidities. We performed a systematic review and meta-analysis to evaluate the differences in NPSLE manifestations in early-onset (<50-year-old) vs late-onset (≥50-year-old) SLE patients.

METHODS

A literature search was performed using the PubMed, Web of Science and Cochrane Library databases. Studies available in English (1959-2022) including a late-onset SLE comparison group and evaluating the frequency of NPSLE were eligible. A forest plot was used to compare odds ratios (95% CI) of incidence and manifestations of NPSLE by age groups. Study heterogeneity was assessed using I2 statistics.

RESULTS

A total of 44 studies, including 17 865 early-onset and 2970 late-onset SLE patients, fulfilled our eligibility criteria. CNS involvement was reported in 3326 patients. Cumulative NPSLE frequency was higher in the early-onset group than in the late-onset group (OR: 1.41, 95% CI: 1.24, 1.59, P < 0.0001). In early-onset SLE patients, seizures (OR: 1.68, 95% CI: 1.27, 2.22) and psychosis (OR: 1.72, 95% CI: 1.23, 2.41) were more common than in late-onset SLE patients (P values, 0.0003 and 0.0014, respectively). Peripheral neuropathy was more commonly reported in the late-onset SLE group than in the early-onset SLE group (OR: 0.64, 95% CI: 0.47, 0.86, P = 0.004).

CONCLUSION

Our meta-analysis revealed that the frequencies of overall NPSLE, seizures, and psychosis were less common in late-onset SLE patients than in early-onset SLE patients. In contrast, peripheral neuropathy was more common in the late-onset SLE group.

sTREM-1 promotes the phagocytic function of microglia to induce hippocampus damage via the PI3K-AKT signaling pathway

Soluble triggering receptor expressed on myeloid cells-1 (sTREM-1) is a soluble form of TREM-1 released during inflammation. Elevated sTREM-1 levels have been found in neuropsychiatric systemic lupus erythematosus (NPSLE) patients; yet, the exact mechanisms remain unclear. This study investigated the role of sTREM-1 in brain damage and its underlying mechanism. The sTREM-1 recombinant protein (2.5 μg/3 μL) was injected into the lateral ventricle of C57BL/6 female mice. After intracerebroventricular (ICV) injection, the damage in hippocampal neurons increased, and the loss of neuronal synapses and activation of microglia increased compared to the control mice (treated with saline). In vitro. after sTREM-1 stimulation, the apoptosis of BV2 cells decreased, the polarization of BV2 cells shifted to the M1 phenotype, the phagocytic function of BV2 cells significantly improved, while the PI3K-AKT signal pathway was activated in vivo and in vitro. PI3K-AKT pathway inhibitor LY294002 reversed the excessive activation and phagocytosis of microglia caused by sTREM-1 in vivo and in vitro, which in turn improved the hippocampus damage. These results indicated that sTREM-1 activated the microglial by the PI3K-AKT signal pathway, and promoted its excessive phagocytosis of the neuronal synapse, thus inducing hippocampal damage. sTREM-1 might be a potential target for inducing brain lesions.

Analysis of clinical characteristics of children with Aicardi-Goutieres syndrome in China

BACKGROUND

Aicardi-Goutieres syndrome (AGS) is an inflammatory disorder belonging to the type I interferonopathy group. The clinical diagnosis of AGS is difficult, which can lead to a high mortality rate. Overall, there is a lack of large-sample research data on AGS in China. We aim to summarize the clinical characteristics of Chinese patients with AGS and provide clues for clinical diagnostic.

METHODS

The genetic and clinical features of Chinese patients with AGS were collected. Real-time polymerase chain reaction was used to detect expression of interferon-stimulated genes (ISGs).

RESULTS

A total of 23 cases were included, consisting of 7 cases of AGS1 with three prime repair exonuclease 1 mutations, 3 of AGS2 with ribonuclease H2 subunit B (RNASEH2B) mutations, 3 of ASG3 with RNASEH2C, 1 of AGS4 with RNASEH2A mutations, 2 of AGS6 with adenosine deaminase acting on RNA 1 mutations, and 7 of AGS7 with interferon induced with helicase C domain 1 mutations. Onset before the age of 3 years occurred in 82.6%. Neurologic involvement was most common (100%), including signs of intracranial calcification which mainly distributed in the bilateral basal ganglia, leukodystrophy, dystonia, epilepsy, brain atrophy and dysphagia. Intellectual disability, language disability and motor skill impairment were also observed. Skin manifestations (60.87%) were dominated by a chilblain-like rash. Features such as microcephaly (47.62%), short stature (52.38%), liver dysfunction (42.11%), thyroid dysfunction (46.15%), positive autoimmune antibodies (66.67%), and elevated erythrocyte sedimentation rate (53.85%) were also found. The phenotypes of 2 cases fulfilled the diagnostic criteria for systemic lupus erythaematosus (SLE). One death was recorded. ISGs expression were elevated.

CONCLUSIONS

AGS is a systemic disease that causes sequelae and mortality. A diagnosis of AGS should be considered for patients who have an early onset of chilblain-like rash, intracranial calcification, leukodystrophy, dystonia, developmental delay, positive autoimmune antibodies, and elevated ISGs, and for those diagnosed with SLE with atypical presentation who are nonresponsive to conventional treatments. Comprehensive assessment of vital organ function and symptomatic treatment are important.

CXCL13 Neutralization Attenuates Neuropsychiatric Manifestations in Lupus-Prone Mice

Neuropsychiatric lupus (NPSLE), the nervous system presentation of systemic lupus erythematosus (SLE), remains challenging to treat due to its unclear pathogenesis and lack of available targeted therapies. A potential contributor to disease progression is brain tertiary lymphoid structures (TLS); these ectopic lymphoid follicles that can develop tissue-targeted antibodies have recently been described in the MRL/lpr lupus mouse strain, a classic model for studying NPSLE. The brains of MRL/lpr mice show a significant increase of CXCL13, an important chemokine in lymphoid follicle formation and retention that may also play a role in the disease progression of NPSLE. The aim of the present study was to inhibit CXCL13 and examine the effect of this intervention on lymphoid formation and the development of neurobehavioral manifestations in lupus mice. Female MRL/lpr mice were injected with an anti-CXCL13 antibody, an IgG1 isotype-matched antibody, or PBS either three times a week for 12 weeks intraperitoneally (IP) starting at 6-8 weeks of age, or continuously intracerebroventricularly (ICV) with an osmotic pump over a two-week period starting at 15 weeks of age. Cognitive dysfunction and depression-like behavior were assessed at the end of treatment. When treatment was delivered IP, anti-CXCL13 treated mice showed significant improvement in cognitive function when compared to control treated mice. Depression-like behavior was attenuated as well. Furthermore, mice that received anti-CXCL13 by the ICV route showed similar beneficial effects. However, the extent of lymphocyte infiltration into the brain and the general composition of the aggregates were not substantively changed by anti-CXCL13 irrespective of the mode of administration. Nevertheless, analysis of brain gene expression in anti-CXCL13 treated mice showed significant differences in key immunological and neuro-inflammatory pathways that most likely explained the improvement in the behavioral phenotype. Our results indicate that CXCL13 affects the behavioral manifestations in the MRL/lpr strain and is important to the pathogenesis of murine NPSLE, suggesting it as a potential therapeutic target.