Systematic Review and Metanalysis of the Expression of Blood-Based and Cerebrospinal Fluid-Based Biomarkers Related to Inflammatory Mediators in Neuropathic Pain.

BACKGROUND: The understanding of neuropathic pain remains incomplete, highlighting the need for research on biomarkers for improved diagnosis and treatment. This review focuses on identifying potential biomarkers in blood and cerebrospinal fluid for neuropathic pain in different neuropathies. METHODS: Searches were performed in six databases: PubMed, Web of Science, Scopus, Cochrane Library, EMBASE, and CINAHL. Included were observational studies, namely cross-sectional, cohort, and case-control, that evaluated quantitative biomarkers in blood or cerebrospinal fluid. Data were qualitatively synthesized, and meta-analyses were conducted using R. The study is registered with PROSPERO under the ID CRD42022323769. RESULTS: The literature search resulted in 16 studies for qualitative and 12 for quantitative analysis, covering patients over 18 years of age with painful neuropathies. A total of 1403 subjects were analyzed, identifying no significant differences in levels of C-Reactive Protein (CRP), Interleukin-6 (IL-6), and Tumor Necrosis Factor-alpha (TNF-alpha) between patients with and without pain. Despite the high inter-rater reliability and adequate bias assessment, the results suggest negligible differences in inflammatory biomarkers, with noted publication bias and heterogeneity among studies, indicating the need for further research. CONCLUSIONS: Our review underscores the complex nature of neuropathic pain and the challenges in identifying biomarkers, with no significant differences found in CRP, IL-6, and TNF-alpha levels between patients with and without pain. Despite methodological robustness, the results are limited by publication bias and heterogeneity. This emphasizes the need for further research to discover definitive biomarkers for improved diagnosis and personalized treatment of neuropathic pain.

Following the Clues: Usefulness of Biomarkers of Neuroinflammation and Neurodegeneration in the Investigation of HTLV-1-Associated Myelopathy Progression.

Human T-lymphotropic virus type 1 (HTLV-1)-associated myelopathy/tropical spastic paraparesis (HAM/TSP) is a neurodegenerative disease due to axonal damage of the corticospinal secondary to an inflammatory response against infected T-cells. In the present work, we aimed to evaluate biomarkers of neurodegeneration and neuroinflammation in the definition of HAM/TSP prognosis. Neurofilament light (NfL) and phosphorylated heavy (pNfH) chains, total Tau protein, cellular prion protein (PrPc), inflammatory chemokines, and neopterin were quantified in paired cerebrospinal fluid (CSF) and serum samples from HAM/TSP patients (n=21), HTLV-1 asymptomatic carriers (AC) (n=13), and HTLV-1 seronegative individuals with non-inflammatory non-degenerative neurological disease (normal-pressure hydrocephalus) (n=9) as a control group. HTLV-1 proviral load in peripheral blood mononuclear cells and the expression of chemokine receptors CCR4, CCR5, and CXCR3 in infected CD4+ T-cells (HTLV-1 Tax+ cells) were also assessed. CSF levels of Tau, NfL, and pNfH were similar between groups, but PrPc and neopterin were elevated in HAM/TSP patients. Most individuals in the control group and all HTLV-1 AC had CSF/serum neopterin ratio < 1.0, and two-thirds of HAM/TSP patients had ratio values > 1.0, which positively correlated with the speed of disease progression and pNfH levels, indicating active neuroinflammation. HAM/TSP patients showed high serum levels of CXCR3-binding chemokines (CXCL9, CXCL10, and CXCL11) and elevated CSF levels of CCL2, CCL3, CCL4, CCL17, CXCL5, CXCL10, and CXCL11. Indeed, CXCL10 concentration in CSF of HAM/TSP patients was 5.8-fold and 8.7-fold higher in than in HTLV-1 AC and controls, respectively, and correlated with CSF cell counts. HAM/TSP patients with typical/rapid disease progression had CSF/serum CXCL10 ratio > 1.0 and a higher frequency of CXCR3+Tax+CD4+ T-cells in blood, which indicated a positive gradient for the migration of infected cells and infiltration into the central nervous system. In conclusion, the slow progression of HAM/TSP abrogates the usefulness of biomarkers of neuronal injury for the disease prognosis. Thus, markers of inflammation provide stronger evidence for HAM/TSP progression, particularly the CSF/serum neopterin ratio, which may contribute to overcome differences between laboratory assays.

Cytokine response in cerebrospinal fluid of meningitis patients and outcome associated with pneumococcal serotype.

Streptococcus pneumoniae causes life-threatening meningitis. Its capsular polysaccharide determines the serotype and influences disease severity but the mechanism is largely unknown. Due to evidence of elevated cytokines levels in the meningeal inflammatory response, we measured 41 cytokines/chemokines and growth factors in cerebrospinal fluid (CSF) samples from 57 South African meningitis patients (collected in the period 2018-2019), with confirmed S. pneumoniae serotypes, using a multiplexed bead-based immunoassay. Based on multivariable Bayesian regression, using serotype 10A as a reference and after adjusting for HIV and age, we found IL-6 concentrations significantly lower in patients infected with serotypes 6D (undetectable) and 23A (1601 pg/ml), IL-8 concentrations significantly higher in those infected with 22A (40,459 pg/ml), 7F (32,400 pg/ml) and 15B/C (6845 pg/ml), and TNFα concentration significantly higher in those infected with serotype 18A (33,097 pg/ml). Although a relatively small number of clinical samples were available for this study and 28% of samples could not be assigned to a definitive serotype, our data suggests 15B/C worthy of monitoring during surveillance as it is associated with in-hospital case fatality and not included in the 13-valent polysaccharide conjugate vaccine, PCV13. Our data provides average CSF concentrations of a range of cytokines and growth factors for 18 different serotypes (14, 19F, 3, 6A, 7F, 19A, 8, 9N, 10A, 12F, 15B/C, 22F, 16F, 23A, 31, 18A, 6D, 22A) to serve as a basis for future studies investigating host-pathogen interaction during pneumococcal meningitis. We note that differences in induction of IL-8 between serotypes may be particularly worthy of future study.

Cerebrospinal fluid levels of L-glutamate signal central inflammatory neurodegeneration in multiple sclerosis.

Excessive extracellular concentrations of L-glutamate (L-Glu) can be neurotoxic and contribute to neurodegenerative processes in multiple sclerosis (MS). The association between cerebrospinal fluid (CSF) L-Glu levels, clinical features, and inflammatory biomarkers in patients with MS remains unclear. In 179 MS patients (relapsing remitting, RR, N = 157; secondary progressive/primary progressive, SP/PP, N = 22), CSF levels of L-Glu at diagnosis were determined and compared with those obtained in a group of 40 patients with non-inflammatory/non-degenerative disorders. Disability at the time of diagnosis, and after 1 year follow-up, was assessed using the Expanded Disability Status Scale (EDSS). CSF concentrations of lactate and of a large set of pro-inflammatory and anti-inflammatory molecules were explored. CSF levels of L-Glu were slightly reduced in MS patients compared to controls. In RR-MS patients, L-Glu levels correlated with EDSS after 1 year follow-up. Moreover, in MS patients, significant correlations were found between L-Glu and both CSF levels of lactate and the inflammatory molecules interleukin (IL)-2, IL-6, and IL-1 receptor antagonist. Altered expression of L-Glu is associated with disability progression, oxidative stress, and inflammation. These findings identify CSF L-Glu as a candidate neurochemical marker of inflammatory neurodegeneration in MS.

High Level of Soluble CD146 In Cerebrospinal Fluid Might be a Biomarker of Severity of Anti-N-Methyl-D-Aspartate Receptor Encephalitis.

Background: Disruption of the blood-brain barrier (BBB) is an important pathophysiological process of anti-N-methyl-D-aspartate receptor (anti-NMDAR) encephalitis. A recent multi-center study showed that soluble (s) CD146 is a potential biomarker for monitoring early BBB damage and central nervous system inflammation, but little is known about sCD146 in anti-NMDAR encephalitis. Method: Twenty-three anti-NMDAR encephalitis patients and seventeen controls with non-inflammatory neurological diseases were recruited. sCD146 and inflammatory cytokines in cerebrospinal fluid (CSF) and serum were detected by ELISA. Modified Rankin scale (mRS) scores were used to assess the neurological status of each patient. A follow-up review was completed three months after discharge. Results: sCD146 levels in the CSF of patients with the acute stage anti-NMDAR encephalitis were significantly increased compared with controls and accompanied by increases in TNF-α, IL-6 and IL-10. CSF sCD146 was positively correlated with neuroinflammatory factors in the CSF and with mRS score. Three months after effective treatment, CSF sCD146 in patients was significantly decreased but remained significantly different compared with the controls. Conclusion: Our data suggested that higher expression of CSF sCD146 correlated with more serious neurological damage. Therefore, levels of CSF sCD146 may represent a promising indicator for monitoring disease and optimizing clinical treatment decisions in the early stages of anti-NMDAR encephalitis.

Cerebrospinal fluid immune markers and HIV-associated neurocognitive impairments: A systematic review.

HIV-1 is responsible for the development of a spectrum of cognitive impairments known as HIV-associated neurocognitive disorder (HAND). In the era of antiretroviral therapy (ART), HAND remains prevalent in people living with HIV (PLWH), despite low or undetectable viral loads. Persistent neuroinflammation likely plays an important role in the contributing biological mechanisms. Multiple cerebrospinal fluid (CSF) immune markers have been studied but it is unclear which markers most consistently correlate with neurocognitive impairment. We therefore conducted a systematic review of studies of the association of CSF immune markers with neurocognitive performance in ART-experienced PLWH. We aimed to synthesize the published data to determine consistent findings and to indicate the most noteworthy CSF markers of HAND. Twenty-nine studies were included, with 20 cross-sectional studies and 9 longitudinal studies. From the group of markers most often assayed, specific monocyte activation (higher levels of Neopterin, sCD163, sCD14) and neuroinflammatory markers (higher levels of IFN-γ, IL-1α, IL-7, IL-8, sTNFR-II and lower levels of IL-6) showed a consistent direction in association with HIV-associated neurocognitive impairment. Furthermore, significant differences exist in CSF immune markers between HIV-positive people with and without neurocognitive impairment, regardless of viral load and nadir/current CD4+ count. These markers may be useful in furthering our understanding of the neuropathology, diagnosis and prognosis of HAND. Studies using prospective designs (i.e. pre- and post-interventions), "multi-modal" methods (e.g. imaging, inflammation and neurocognitive evaluations) and utilizing a combination of the markers most commonly associated with HAND may help delineate the mechanisms of HAND.

Inflammatory profile in a canine model of hypothermic circulatory arrest.

BACKGROUND: Hypothermic circulatory arrest (HCA) is a technique used for complex repair of the aorta, but it can be associated with neurologic morbidity. To better understand the molecular changes that underlie ischemic brain injury, we assessed gene expression and cytokine/chemokine polypeptide concentration in brain tissue and cerebrospinal fluid (CSF) of canines that underwent two hours of HCA. MATERIALS AND METHODS: Adult male canines were cannulated peripherally for cardiopulmonary bypass, cooled to 18°C, and arrested for two hours. Animals were euthanized two, eight, or 24 hours post-HCA (n = 8 per group), and their brains were compared to brains from eight normal canines, using gene expression microarray analysis, cytokine assay, and histopathology. RESULTS: Two to eight hours after HCA, pro-inflammatory cytokine mRNAs increased markedly, and gene expression was enriched within signaling pathways related to neuroinflammation or ischemic injury. Concentrations of pro-inflammatory cytokine polypeptides IL-6, IL-8, IL-1ß, and CCL2 were very low in normal canine brain, whereas anti-inflammatory IL-10 and TGF-ß1 were expressed at moderate levels. Pro-inflammatory cytokine concentrations rose robustly in cerebral tissue and CSF after HCA. IL-6 and IL-8 peaked at eight hours and declined at 24 hours, while IL-1ß and CCL2 remained elevated. Concentrations of anti-inflammatory IL-10 and TGF-ß1 were maintained after HCA, with a significant increase in TGF-ß1 at 24 hours. CONCLUSIONS: These cytokines represent potential diagnostic markers for ischemic neurologic injury that could be used to assess neurologic injury in patients undergoing HCA. The cellular mechanisms underlying this pro-inflammatory, ischemic-induced injury represent potential targets for neuroprotection in the future.

Classification of neurological diseases using multi-dimensional CSF analysis.

Although CSF analysis routinely enables the diagnosis of neurological diseases, it is mainly used for the gross distinction between infectious, autoimmune inflammatory, and degenerative disorders of the CNS. To investigate, whether a multi-dimensional cellular blood and CSF characterization can support the diagnosis of clinically similar neurological diseases, we analysed 546 patients with autoimmune neuroinflammatory, degenerative, or vascular conditions in a cross-sectional retrospective study. By combining feature selection with dimensionality reduction and machine learning approaches we identified pan-disease parameters that were altered across all autoimmune neuroinflammatory CNS diseases and differentiated them from other neurological conditions and inter-autoimmunity classifiers that subdifferentiate variants of CNS-directed autoimmunity. Pan-disease as well as diseases-specific changes formed a continuum, reflecting clinical disease evolution. A validation cohort of 231 independent patients confirmed that combining multiple parameters into composite scores can assist the classification of neurological patients. Overall, we showed that the integrated analysis of blood and CSF parameters improves the differential diagnosis of neurological diseases, thereby facilitating early treatment decisions.

Zika-exposed microcephalic neonates exhibit higher degree of inflammatory imbalance in cerebrospinal fluid.

Not every neonate with congenital Zika virus (ZIKV) infection (CZI) is born with microcephaly. We compared inflammation mediators in CSF (cerebrospinal fluid obtained from lumbar puncture) between ZIKV-exposed neonates with/without microcephaly (cases) and controls. In Brazil, in the same laboratory, we identified 14 ZIKV-exposed neonates during the ZIKV epidemic (2015-2016), 7(50%) with and 7(50%) without microcephaly, without any other congenital infection, and 14 neonates (2017-2018) eligible to be controls and to match cases. 29 inflammation mediators were measured using Luminex immunoassay and multidimensional analyses were employed. Neonates with ZIKV-associated microcephaly presented substantially higher degree of inflammatory perturbation, associated with uncoupled inflammatory response and decreased correlations between concentrations of inflammatory biomarkers. The groups of microcephalic and non-microcephalic ZIKV-exposed neonates were distinguished from the control group (area under curve [AUC] = 1; P < 0.0001). Between controls and those non-microcephalic exposed to ZIKV, IL-1ß, IL-3, IL-4, IL-7 and EOTAXIN were the top CSF markers. By comparing the microcephalic cases with controls, the top discriminant scores were for IL-1ß, IL-3, EOTAXIN and IL-12p70. The degree of inflammatory imbalance may be associated with microcephaly in CZI and it may aid additional investigations in experimental pre-clinical models testing immune modulators in preventing extensive damage of the Central Nervous System.

A pilot study of inflammatory mediators in brain extracellular fluid in paediatric TBM.

Tuberculous meningitis (TBM) is the most fatal form of tuberculosis and frequently occurs in children. The inflammatory process initiates secondary brain injury processes that lead to death and disability. Much remains unknown about this cerebral inflammatory process, largely because of the difficulty in studying the brain. To date, studies have typically examined samples from sites distal to the site of disease, such as spinal cerebrospinal fluid (CSF) and blood. In this pilot study, we examined the feasibility of using direct brain microdialysis (MD) to detect inflammatory mediators in brain extracellular fluid (ECF) in TBM. MD was used to help guide neurocritical care in 7 comatose children with TBM by monitoring brain chemistry for up to 4 days. Remnant ECF fluid was stored for offline analysis. Samples of ventricular CSF, lumbar CSF and blood were collected at clinically indicated procedures for comparison. Inflammatory mediators were quantified using multiplex technology. All inflammatory markers, with the exception of interleukin (IL)-10 and IL-12p40, were detected in the ECF. Cytokine concentrations were generally lower in ECF than ventricular CSF in time-linked specimens. Individual cases showed ECF cytokine increases coinciding with marked increases in ECF glycerol or decreases in ECF glucose. Cytokine levels and glycerol were generally higher in patients with more severe disease. This is the first report of inflammatory marker analysis from samples derived directly from the brain and in high temporal resolution, demonstrating feasibility of cerebral MD to explore disease progression and possibly therapy response in TBM.

Inflammatory Cytokine Patterns Associated with Neurological Diseases in Coronavirus Disease 2019.

Patients with coronavirus disease 2019 (COVID-19) can present with distinct neurological manifestations. This study shows that inflammatory neurological diseases were associated with increased levels of interleukin (IL)-2, IL-4, IL-6, IL-10, IL-12, chemokine (C-X-C motif) ligand 8 (CXCL8), and CXCL10 in the cerebrospinal fluid. Conversely, encephalopathy was associated with high serum levels of IL-6, CXCL8, and active tumor growth factor ß1. Inflammatory syndromes of the central nervous system in COVID-19 can appear early, as a parainfectious process without significant systemic involvement, or without direct evidence of severe acute respiratory syndrome coronavirus 2 neuroinvasion. At the same time, encephalopathy is mainly influenced by peripheral events, including inflammatory cytokines. ANN NEUROL 2021;89:1041-1045.

Inflammatory Leptomeningeal Cytokines Mediate COVID-19 Neurologic Symptoms in Cancer Patients.

SARS-CoV-2 infection induces a wide spectrum of neurologic dysfunction that emerges weeks after the acute respiratory infection. To better understand this pathology, we prospectively analyzed of a cohort of cancer patients with neurologic manifestations of COVID-19, including a targeted proteomics analysis of the cerebrospinal fluid. We find that cancer patients with neurologic sequelae of COVID-19 harbor leptomeningeal inflammatory cytokines in the absence of viral neuroinvasion. The majority of these inflammatory mediators are driven by type II interferon and are known to induce neuronal injury in other disease states. In these patients, levels of matrix metalloproteinase-10 within the spinal fluid correlate with the degree of neurologic dysfunction. Furthermore, this neuroinflammatory process persists weeks after convalescence from acute respiratory infection. These prolonged neurologic sequelae following systemic cytokine release syndrome lead to long-term neurocognitive dysfunction. Our findings suggest a role for anti-inflammatory treatment(s) in the management of neurologic complications of COVID-19 infection.

Interleukin 6 in cerebrospinal fluid is a biomarker for delayed cerebral ischemia (DCI) related infarctions after aneurysmal subarachnoid hemorrhage.

Interleukin 6 (IL-6) is a prominent proinflammatory cytokine and has been discussed as a potential biomarker for delayed cerebral ischemia (DCI) following aneurysmal subarachnoid hemorrhage. In the present study we have analyzed the time course of serum and cerebrospinal fluid (CSF) IL-6 levels in 82 patients with severe aneurysmal subarachnoid hemorrhage (SAH) requiring external ventricular drains in correlation to angiographic vasospasm, delayed cerebral ischemia, secondary infarctions and other clinical parameters. We observed much higher daily mean IL-6 levels (but also large interindividual variations) in the CSF than the serum of the patients with a peak between days 4 and 14 including a maximum on day 5 after SAH. Individual CSF peak levels correlated significantly with DCI (mean day 4-14 peak, DCI: 26,291 ± 24,159 pg/ml vs. no DCI: 16,184 ± 13,163 pg/ml; P = 0.023). Importantly, CSF IL-6 levels differed significantly between cases with DCI and infarctions and patients with DCI and no infarction (mean day 4-14 peak, DCI with infarction: 37,209 ± 26,951 pg/ml vs. DCI, no infarction: 15,123 ± 11,239 pg/ml; P = 0.003), while findings in the latter patient group were similar to cases with no vasospasm (mean day 4-14 peak, DCI, no infarction: 15,123 ± 11,239 vs. no DCI: 15,840 ± 12,979; P = 0.873). Together, these data support a potential role for elevated CSF IL-6 levels as a biomarker for DCI with infarction rather than for DCI in general. This fits well with a growing body of evidence linking neuroinflammation to ischemia and infarction, but (together with the large interindividual variations observed) limits the diagnostic usefulness of CSF IL-6 levels in SAH patients.

Cerebrospinal fluid cytokines and metalloproteinases in cerebral amyloid angiopathy-related inflammation.

OBJECTIVES: To clarify pathomechanisms of cerebral amyloid angiopathy-related inflammation/vasculitis (CAA-ri). METHODS: We collected cerebrospinal fluid (CSF) samples of nine patients with CAA-ri of before (acute CAA-ri group) and after treatment (post-treatment CAA-ri group) and nine patients with CAA (CAA without inflammation group). We examined anti-amyloid ß protein (Aß) antibody titer by ELISA, and measured 27 Cytokines, nine matrix metalloproteinases (MMPs), and four tissue inhibitors of MMPs (TIMPs) by multiplexed fluorescent bead-based immunoassay. RESULTS: We demonstrated TIMP-2 (median) in CSF of the acute CAA-ri group (30,994.49 pg/ml, p = 0.007) and the post-treatment CAA-ri group (36,430.97 pg/ml, p = 0.001) was significantly elevated compared to that of the CAA without inflammation group (22,013.58 pg/ml). TIMP-1 was also higher in the post-treatment CAA-ri group than that in the CAA without inflammation group (58,167.75 pg/ml vs. 45,770.03 pg/ml, p = 0.005). There was a significant positive correlation between TIMP-1 and anti-Aß antibodies in CAA-ri (rs  = 0.900, p = 0.037). Median MMP-2 tended to be higher in the acute and post-treatment CAA-ri groups (10,619.82 pg/ml and 8396.98 pg/ml, respectively) than in the CAA without inflammation group (4436.34 pg/ml). Platelet-derived growth factor (PDGF)-BB levels before treatment were higher than those after treatment (median, 12.66 pg/ml vs. 6.39 pg/ml; p = 0.011) and correlated with the titer of anti-Aß antibodies (rs  =0.900, p = 0.037). CONCLUSIONS: Elevated levels of MMP-2, TIMP-1, and TIMP-2 might be related to the development of CAA-ri. Elevation of PDGF-BB could be a useful marker for clinical diagnosis of CAA-ri.

Detection of NUCB2/nesfatin-1 in cerebrospinal fluid of multiple sclerosis patients.

NUCB2/nesfatin-1 was originally discovered as an anorexigenic peptide. However, recent studies revealed various additional functions including the regulation of inflammation. However, there are no studies that investigated the involvement of NUCB2/nesfatin-1 in neuroinflammatory diseases. Here, we aimed to investigate the involvement of NUCB2/nesfatin-1 in a representative neuroinflammatory disease, multiple sclerosis (MS). Cerebrospinal fluids (CSF) were collected from 24 MS patients and 10 control subjects and NUCB2/nesfatin-1, proinflammatory cytokines (TNF-α, IL-1ß) and anti-inflammatory cytokines (IL-10, TGF-ß) levels were measured by using ELISA assay. Also the expression of NUCB2/nesfatin-1 in the CSF of MS patient was investigated by western blot analysis. Expression of NUCB2/nesfatin-1 was confirmed in the CSF of the MS patient by western blot analysis. NUCB2/nesfatin-1 levels were significantly higher in the CSF of the MS patients. Among the measured cytokines, only IL-1ß was lower in the CSF of the MS patients. We report for the first time increased NUCB2/nesfatin-1 levels in the CSF of MS patients.

Elevated inflammatory proteins in cerebrospinal fluid from patients with painful knee osteoarthritis are associated with reduced symptom severity.

Neuroinflammation and periphery-to-CNS neuroimmune cross-talk in patients with painful knee osteoarthritis (OA) are poorly understood. We utilized proximity extension assay to measure the level of 91 inflammatory proteins in CSF and serum from OA patients and controls. The patients had elevated levels of 48 proteins in CSF indicating neuroinflammation. Ten proteins were correlated between CSF and serum and potentially involved in periphery-to-CNS neuroimmune cross-talk. Seven CSF proteins, all with previously reported neuroprotective effects, were associated with lower pain intensity and milder knee-related symptoms. Our findings indicate that neuroinflammation in OA could be protective and associated with less severe symptoms.

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

BACKGROUND: Autoantibodies (auto Abs) and inflammatory mediators (IMs) in cerebrospinal fluid (CSF) may be involved in the pathogenesis of neuropsychiatric systemic lupus erythematosus (NPSLE). It is suggested that anti-N-methyl D-aspartate receptor NR2 subunit (NR2) Ab can develop NP manifestation after blood-brain barrier (BBB) abruption. We also reported the association between NPSLE and CSF anti-U1RNP Ab. In the present study, combined effects of CSF anti-NR2 and anti-U1RNP Abs on IMs in patients with NPSLE were examined. METHODS: CSF samples were collected from 69 patients with NPSLE and 13 non-NPSLE controls. CSF anti-NR2 and anti-U1RNP Abs were determined using ELISA. Levels of IL-6, IL-8, and monokine induced by IFN-γ (MIG) in CSF were measured by quantitative multiplex cytokine analysis. RESULTS: CSF IL-6 levels were higher in CSF anti-NR2-positive than in CSF anti-NR2-negative patients (p = 0.003) and non-NPSLE controls (p = 0.015) and were positively correlated with anti-NR2 titer (r = 0.42). CSF IL-8 levels were higher in CSF anti-U1RNP-positive than in CSF anti-U1RNP-negative patients (p = 0.041). CSF MIG levels were more elevated in CSF anti-NR2-positive (p = 0.043) and anti-U1RNP-positive patients (p = 0.029) than in non-NPSLE controls. Additionally, in double positive (DP; both anti-NR2 and U1RNP Ab positive) group, CSF IL-6 and MIG levels were significantly higher than in the double negative (DN; both anti-NR2 and U1RNP Ab negative) group. However, combined effect of both Abs on IM elevation and clinical manifestation was not clear. CONCLUSIONS: CSF anti-NR2 and anti-U1RNP Abs have different effects on the elevation of CSF IM levels in patients with NPSLE. Additional effect of anti-U1RNP Abs on anti-NR2 Ab-mediated NP manifestation, however, was not recognized in our study.

Searching for autoimmune encephalitis: Beware of normal CSF.

OBJECTIVE: To determine the prevalence of cerebrospinal fluid (CSF) markers associated with inflammation (i.e., elevated white blood cell count, protein concentration, and CSF-specific oligoclonal bands) in patients with early active autoimmune encephalitis (AE). METHODS: CSF characteristics, including WBC count, protein concentration, and oligoclonal banding, were analyzed in patients diagnosed with AE at two tertiary care centers. RESULTS: Ninety-five patients were included in the study. CSF white blood cell counts and protein levels were within normal limits for 27% (CI95%: 19-37) of patients with AE. When results of oligoclonal banding were added, 14% (CI95%: 6-16) of patients with AE had "normal" CSF. The median CSF white blood cell count was 8 cells/mm3 (range: 0-544) and the median CSF protein concentration was 0.42 g/L (range: 0.15-3.92). CONCLUSIONS: White blood cell counts and protein levels were within normal limits in the CSF of a substantial proportion of patients with early active AE. Inclusion of CSF oligoclonal banding identified a higher proportion of patients with an inflammatory CSF profile, especially when CSF was sampled early in the disease process.

Protective Role of Cerebrospinal Fluid Inflammatory Cytokines in Patients with Amnestic Mild Cognitive Impairment and Early Alzheimer's Disease Carrying Apolipoprotein E4 Genotype.

BACKGROUND: Neuroinflammatory cytokines can play a pivotal role in Alzheimer's disease (AD) contributing to the evolution of degenerative processes. OBJECTIVE: We aimed at evaluating the levels of cerebrospinal fluid (CSF) inflammatory cytokines, chemokines, and growth factors in subjects with diagnosis of amnestic mild cognitive impairment and mild AD. METHODS: We evaluated CSF contents of inflammatory cytokines in 66 patients divided according to the NIA-AA research framework and the APOE genotype. CSF of a group of cognitively unimpaired individuals (n = 23) was evaluated as control. All patients were evaluated for 24 months using Mini-Mental State Examination (MMSE). RESULTS: We found significant increased levels of IL-4, IL-6, IL-8, and G-CSF in the CSF of A+/T-APOE4 carriers, respect to A+/T-patients homozygous for APOE3, respect to A+/T+ patients, regardless the APOE status, and respect to controls. Over a period of 24 months, A+/T-APOE4 carriers, with increased levels of cytokines, showed a preserved cognitive evaluation when compared to the other subgroups of patients (delta MMSE at 24 months respect to baseline: 0.10±0.35; p < 0.05). CONCLUSION: Our data suggest that during early phases of AD, in APOE4 carriers, Aß pathology likely induces a specific cytokines pattern synthesis associated to cognitive preservation. These data highlight the different role that neuroinflammation can play in AD pathology based on the presence of specific CSF biomarkers and on the APOE status.