The application value of cerebrospinal fluid immunoglobulin in tuberculous meningitis.

This article aims to study the value of cerebrospinal fluid (CSF) immunoglobulin in differential diagnosis, prediction, and prognosis of tuberculous meningitis (TBM). The clinical data of 65 patients with TBM in our hospital were collected, and 65 patients with cryptococcal meningitis (CM) were enrolled in 1:1 matching. Relevant data were collected for comparison. CSFs IgG [331.51 (164.85, 645.00) vs 129.00 (55.05, 251.00) ng/mL], IgM [22.38 (8.52, 40.18) vs 6.08 (2.19, 23.30) ng/mL], and IgA [64.11 (21.44, 115.48) vs 16.55 (4.76, 30.36) ng/mL] in the TBM group were higher than those in the CM group (P < 0.001). In the TBM group, after 24 weeks of treatment, the CSFs IgG, IgM, and IgA were significantly decreased, and the difference was statistically significant (P < 0.05). The predictive results of CSF immunoglobulin for TBM showed that IgG, IgM, and IgA all had some predictive value for TBM, and the combined predictive value of the three was the highest, with an area under the curve of 0.831 (95% CI: 0.774-0.881). Logistic regression analysis of CSF immunoglobulins and TBM prognosis showed that IgG [odds ratio (OR) = 4.796, 95% confidence interval (CI): 2.575-8.864], IgM (OR = 3.456, 95% CI: 2.757-5.754), and IgA (OR = 4.371, 95% CI: 2.731-5.856) were TBM risk factors for poor prognosis in patients. The levels of IgG, IgM, and IgA in CSF were positively correlated with the severity of cranial magnetic resonance imaging (MRI) in TBM patients (R2 = 0.542, F = 65.392, P < 0.05). CSFs IgG, IgM, and IgA can be used as a routine monitoring index for TBM patients, which has a certain reference value in differential diagnosis and efficacy evaluation. IMPORTANCE: In clinical practice, physicians can determine the physical conditions of patients based on the levels of cerebrospinal fluids (CSFs) IgG, IgM, and IgA. Higher levels of CSFs IgG, IgM, and IgA suggest more possibility of tuberculous meningitis and worse prognosis and magnetic resonance imaging manifestations.

Cerebrospinal fluid findings in patients with myelin oligodendrocyte glycoprotein (MOG) antibodies. Part 1: Results from 163 lumbar punctures in 100 adult patients.

BACKGROUND: New-generation cell-based assays have demonstrated a robust association of serum autoantibodies to full-length human myelin oligodendrocyte glycoprotein (MOG-IgG) with (mostly recurrent) optic neuritis, myelitis, and brainstem encephalitis, as well as with neuromyelitis optica (NMO)-like or acute-disseminated encephalomyelitis (ADEM)-like presentations. However, only limited data are yet available on cerebrospinal fluid (CSF) findings in MOG-IgG-associated encephalomyelitis (MOG-EM; also termed MOG antibody-associated disease, MOGAD). OBJECTIVE: To describe systematically the CSF profile in MOG-EM. MATERIAL AND METHODS: Cytological and biochemical findings (including white cell counts and differentiation; frequency and patterns of oligoclonal bands; IgG/IgM/IgA and albumin concentrations and CSF/serum ratios; intrathecal IgG/IgA/IgM fractions; locally produced IgG/IgM/IgA concentrations; immunoglobulin class patterns; IgG/IgA/IgM reibergrams; Link index; measles/rubella/zoster (MRZ) reaction; other anti-viral and anti-bacterial antibody indices; CSF total protein; CSF L-lactate) from 163 lumbar punctures in 100 adult patients of mainly Caucasian descent with MOG-EM were analyzed retrospectively. RESULTS: Most strikingly, CSF-restricted oligoclonal IgG bands, a hallmark of multiple sclerosis (MS), were absent in almost 90% of samples (N = 151), and the MRZ reaction, the most specific laboratory marker of MS known so far, in 100% (N = 62). If present, intrathecal IgG (and, more rarely, IgM) synthesis was low, often transient and mostly restricted to acute attacks. CSF WCC was elevated in > 50% of samples (median 31 cells/µl; mostly lymphocytes and monocytes; > 100/µl in 12%). Neutrophils were present in > 40% of samples; activated lymphocytes were found less frequently and eosinophils and/or plasma cells only very rarely (< 4%). Blood-CSF barrier dysfunction (as indicated by an elevated albumin CSF/serum ratio) was present in 48% of all samples and at least once in 55% of all patients (N = 88) tested. The frequency and degree of CSF alterations were significantly higher in patients with acute myelitis than in patients with acute ON and varied strongly depending on attack severity. CSF L-lactate levels correlated significantly with the spinal cord lesion load in patients with acute myelitis (p < 0.0001). Like pleocytosis, blood-CSF barrier dysfunction was present also during remission in a substantial number of patients. CONCLUSION: MOG-IgG-positive EM is characterized by CSF features that are distinct from those in MS. Our findings are important for the differential diagnosis of MS and MOG-EM and add to the understanding of the immunopathogenesis of this newly described autoimmune disease.

Cerebrospinal fluid findings in patients with myelin oligodendrocyte glycoprotein (MOG) antibodies. Part 2: Results from 108 lumbar punctures in 80 pediatric patients.

BACKGROUND: New-generation, cell-based assays have demonstrated a robust association of serum autoantibodies to full-length human myelin oligodendrocyte glycoprotein (MOG-IgG) with (mostly recurrent) optic neuritis, myelitis, and brainstem encephalitis, as well as with neuromyelitis optica (NMO)-like or acute-disseminated encephalomyelitis (ADEM)-like presentations. However, only limited data are yet available on cerebrospinal fluid (CSF) findings in MOG-IgG-associated encephalomyelitis (MOG-EM; also termed MOG antibody-associated disease, MOGAD). OBJECTIVE: To describe systematically the CSF profile in children with MOG-EM. MATERIAL AND METHODS: Cytological and biochemical findings (including white cell counts [WCC] and differentiation; frequency and patterns of oligoclonal bands; IgG/IgM/IgA and albumin concentrations and CSF/serum ratios; intrathecal IgG/IgM/IgA fractions; locally produced IgG/IgM/IgA concentrations; immunoglobulin class patterns; IgG/IgA/IgM reibergrams; Link index; measles/rubella/zoster [MRZ] reaction; other anti-viral and anti-bacterial antibody indices; CSF total protein; CSF L-lactate) from 108 lumbar punctures in 80 pediatric patients of mainly Caucasian descent with MOG-EM were analyzed retrospectively. RESULTS: Most strikingly, CSF-restricted oligoclonal IgG bands, a hallmark of multiple sclerosis (MS), were absent in 89% of samples (N = 96), and the MRZ reaction, the most specific laboratory marker of MS known so far, in 100% (N = 29). If present at all, intrathecal IgG synthesis was low, often transient and mostly restricted to acute attacks. Intrathecal IgM synthesis was present in 21% and exclusively detectable during acute attacks. CSF WCC were elevated in 54% of samples (median 40 cells/µl; range 6-256; mostly lymphocytes and monocytes; > 100/µl in 11%). Neutrophils were present in 71% of samples; eosinophils, activated lymphocytes, and plasma cells were seen only rarely (all < 7%). Blood-CSF barrier dysfunction (as indicated by an elevated albumin CSF/serum ratio) was present in 46% of all samples (N = 79) and at least once in 48% of all patients (N = 67) tested. CSF alterations were significantly more frequent and/or more pronounced in patients with acute spinal cord or brain disease than in patients with acute ON and varied strongly depending on attack severity. CSF L-lactate levels correlated significantly with the spinal cord lesions load (measured in vertebral segments) in patients with acute myelitis (p = 0.0099). An analysis of pooled data from the pediatric and the adult cohort showed a significant relationship of QAlb (p < 0.0005), CST TP (p < 0.0001), and CSF L-lactate (p < 0.0003) during acute attacks with age. CONCLUSION: MOG-IgG-associated EM in children is characterized by CSF features that are distinct from those in MS. With regard to most parameters, no marked differences between the pediatric cohort and the adult cohort analyzed in Part 1 were noted. Our findings are important for the differential diagnosis of pediatric MS and MOG-EM and add to the understanding of the immunopathogenesis of this newly described autoimmune disease.

Soluble TREM2 and Inflammatory Proteins in Alzheimer's Disease Cerebrospinal Fluid.

The present study explores the associations of soluble TREM2, an important regulator of microglial activity linked to Alzheimer's disease (AD), with other known inflammatory proteins in cerebrospinal fluid (CSF). We studied 303 participants, including 89 controls, 135 mild cognitive impairment, and 79 AD dementia patients. Using established CSF biomarkers, subjects were classified according to the National Institute on Aging-Alzheimer's Association research framework, which groups markers into those of amyloid-ß deposition (A), tau pathology (T), and neurodegeneration (N). TNFR1, TNFR2, TGF-ß1, TGFß2, IL-9, TNF-α, ICAM1, and VCAM1 showed significant concentration differences between the ATN groups, with higher concentrations in more advanced disease categories. sTREM2 was positively associated with the pro-inflammatory proteins TNF-α, TNFR1, TNFR2, ICAM1, VCAM1, and IP-10 and negatively with IL-21; also, positive associations with the anti-inflammatory proteins TGFß1, IL-10, and IL-9 were found. Pathway enrichment analysis highlighted the involvement of sTREM2 in key functional clusters including immunoglobulin and cytokine production and cellular response to lipopolysaccharides, cytokines, and steroid hormones. Our work provides further evidence in support of TREM2 as amarker of neuroinflammatory response in AD.

Free light chains in the cerebrospinal fluid. Comparison of different methods to determine intrathecal synthesis.

Background Free light chains (FLC) have been proposed as diagnostic biomarkers in the cerebrospinal fluid (CSF) of patients with inflammatory central nervous system (CNS) diseases. However, which method to use for determining an intrathecal FLC synthesis has not yet been clarified. The objective of this study was to compare the diagnostic performance of CSF FLC concentration, FLC quotient (QFLC), FLC index and FLC intrathecal fraction (FLCIF). Methods κ- and λ-FLC were measured by nephelometry under blinded conditions in CSF and serum sample pairs of patients with clinically isolated syndrome (CIS; n = 60), multiple sclerosis (MS; n = 60) and other neurological diseases (n = 60) from four different MS centers. QFLC was calculated as the ratio of CSF/serum FLC concentration, the FLC index as QFLC/albumin quotient and the percentage FLCIF by comparing QFLC to a previously empirically determined, albumin quotient-dependent reference limit. Results CSF FLC concentration, QFLC, FLC index and FLCIF of both the κ- and λ-isotype were significantly higher in patients with CIS and MS than in the control group, as well as in oligoclonal bands (OCB) positive than in OCB negative patients. Each parameter was able to identify MS/CIS patients and OCB positivity, however, diagnostic performance determined by receiver operating characteristic (ROC) analyses differed and revealed superiority of FLC index and FLCIF. Conclusions These findings support the diagnostic value of FLC measures that correct for serum FLC levels and albumin quotient, i.e. blood-CSF barrier function.

Clinical utility of a molecular signature in inflammatory demyelinating disease.

Objective: We sought to develop molecular biomarkers of intrathecal inflammation to assist neurologists in identifying patients most likely to benefit from a range of immune therapies. Methods: We used Luminex technology and index determination to search for an inflammatory activity molecular signature (IAMS) in patients with inflammatory demyelinating disease (IDD), other neuroinflammatory diagnoses, and noninflammatory controls. We then followed the clinical characteristics of these patients to find how the presence of the signature might assist in diagnosis and prognosis. Results: A CSF molecular signature consisting of elevated CXCL13, elevated immunoglobulins, normal albumin CSF/serum ratio (Qalbumin), and minimal elevation of cytokines other than CXCL13 provided diagnostic and prognostic value; absence of the signature in IDD predicted lack of subsequent inflammatory events. The signature outperformed oligoclonal bands, which were frequently false positive for active neuroinflammation. Conclusions: A CSF IAMS may prove useful in the diagnosis and management of patients with IDD and other neuroinflammatory syndromes. Classification of evidence: This study provides Class IV evidence that a CSF IAMS identifies patients with IDD.

Inflammation is correlated with severity and outcome of cerebral venous thrombosis.

BACKGROUND: Few studies have suggested a relationship between inflammation and cerebral venous thrombosis (CVT). This retrospective study aimed to explore the changes in inflammation in different CVT stages and the correlation between inflammation and severity and outcome of CVT. METHODS: In total, 95 suitable patients with CVT and 41 controls were compared. Patients with CVT were divided into three groups. The inflammatory factors studied included hypersensitive C-reactive protein (Hs-CRP), interleukin-6 (IL-6), and neutrophil-to-lymphocyte ratio (NLR) in the peripheral blood and immunoglobulin A (IgA), immunoglobulin M (IgM), and immunoglobulin G (IgG) in the cerebrospinal fluid (CSF). The severity of CVT was evaluated with the modified Rankin Scale (mRS), the National Institutes of Health Stroke Scale (NIHSS), fundus condition, intracranial pressure (ICP), and complications on admission. The short-term outcome was evaluated with the mRS at discharge. RESULTS: The following results were obtained: (1) Inflammatory factor levels in patients with CVT were higher than those in the controls. (2) Inflammatory factor levels in the acute and subacute stages were significantly higher than those in the chronic stage (all P < 0.05). (3) Serum NLR and CSF IgM levels were positively related to baseline degree of disability (odds ratio [OR], 1.279, 95% confidence interval [CI] 1.009-1.621, P = 0.042; OR 1.402, 95% CI 1.036-1.896, P = 0.028). The Hs-CRP level was positively correlated with the baseline occurrence of seizure (OR 1.040, 95% CI 1.001-1.080, P = 0.043). The baseline serum NLR (r = 0.244, P = 0.017), CSF IgA (r = 0.615, P < 0.001), CSF IgM (r = 0.752, P < 0.001), and CSF IgG (r = 0.248, P = 0.015) levels were positively associated with NIHSS. (4) The baseline NLR was significantly associated with high risk of poor outcome at discharge (OR 1.339, 95% CI 1.097-1.784, P = 0.007). Moreover, the ROC showed that NLR ≥ 4.205 could better predict the poor outcome at discharge. The data were analyzed using SPSS. CONCLUSIONS: Inflammation may develop after CVT and gradually decrease during the course. Inflammation was significantly correlated with severity on admission and short-term poor outcome at discharge in CVT.

Cerebrospinal Fluid Immunoglobulins as Potential Biomarkers of Chikungunya Encephalitis.

Chikungunya virus causes fever and severe polyarthritis or arthralgia and is associated with neurologic manifestations that are sometimes challenging to diagnose. We demonstrate intrathecal synthesis of chikungunya antibodies in a patient with a history of acute infection complicated by encephalitis. The specificity of the intracerebral immune response supports early chikungunya-associated encephalitis diagnosis.

Blood-Brain Barrier and Intrathecal Immune Response in patients with neuroinfections.

Cerebrospinal fluid/serum albumin ratio is one of the most informative parameters for blood-brain barrier (BBB) integrity in cases of central nervous system (CNS) infectious diseases. Normally, CNS albumin concentration is a function of diffusion processes along with CSF drainage and resorption. In pathological processes CSF albumin levels are dependent only on the rate of CSF drainage resulting in non-linear reciprocal changes of albumin quotient (Qalb). IgG, IgA and IgM concentrations both in CSF and serum can be compared to Qalb, thus determining the intrathecal immune response. The aim of the study was to detect BBB permeability impairment and the intrathecal immune response in patients with CNS infections with various etiologies. CSF/serum ratios were calculated and related to IgG IgA and IgM concentrations in CSF and blood serum. The results were integrated and presented by Reibergrams. The results demonstrated typical patterns which prove albumin to be the main modulator of protein dynamics and at the same time explicates the complex pathophysiological mechanisms involved in BBB disruption and intrathecal immune response in CNS infections. The diagnostic model presented in our study seeks to explain the observations of meningitis and meningoencephalitis pathophysiology and points out the mandatory cooperation between clinicians and laboratory for accurate diagnosis and proper treatment.

Downregulation of Apolipoprotein-E and Apolipoprotein-J in Moyamoya Disease-A Proteome Analysis of Cerebrospinal Fluid.

BACKGROUND AND PURPOSE: Genetic factors are closely involved in the etiology of moyamoya disease (MMD). However, its postgenomic mechanisms are still unknown. This study was aimed to identify specific biomarkers in the cerebrospinal fluid (CSF) of patients with MMD, using quantitative proteome technique. METHODS: This study included 10 patients with MMD and 4 controls. The CSF was collected without blood contamination during surgery. A comparative 2-dimensional gel electrophoresis study (2D-PAGE) was performed. Protein spots that showed significant differences between moyamoya patients and controls were selected for further analysis by mass spectrometry. RESULTS: On 2D-PAGE, 2 proteins were significantly upregulated, and 2 other proteins were downregulated in the CSF of MMD. Further mass spectrometry analysis revealed that haptoglobin and α-1-B-glycoprotein (A1BG) were upregulated. On the other hand, apolipoprotein-E (apoE), apoE precursor, and apolipoprotein-J (apoJ) were significantly downregulated in the CSF of MMD. The observed probability-based MOWSE score was 72 for haptoglobin (P <.05), 521 for A1BG (P <.05), 62 for apoE (P <.05), 72 for apoE precursor (P <.05), and 112 for apoJ (P <.05). CONCLUSION: Although the role of A1BG in the central nervous system is still unknown, the overexpressed haptoglobin may indicate the inflammation and/or angiogenesis in MMD. The downregulation of apoE and apoJ strongly suggests a critical role of lipid metabolism in the development and progression of MMD. These proteins may be novel biomarkers in shedding light on the pathogenesis of MMD, although further studies would be warranted.

Intrathecal immunoglobulin synthesis in patients with symptomatic epilepsy and epilepsy of unknown etiology ('cryptogenic').

BACKGROUND AND PURPOSE: To compare the frequency of intrathecal immunoglobulin (Ig) synthesis in patients with symptomatic epilepsy and epilepsy of unknown etiology ('cryptogenic'). METHODS: Patients with epileptic (n = 301) and non-epileptic (n = 10) seizures were retrospectively screened for autochthonous intrathecal Ig synthesis and oligoclonal bands (OCBs) in the cerebrospinal fluid. RESULTS: Intrathecal IgG/OCBs were detected in 8% of patients with epilepsies of unknown etiology, 5% of patients with first seizures of unknown cause and 0-4% of patients with epilepsy due to brain tumors, cerebrovascular disease or other etiologies. Intrathecal IgG/OCBs were not seen in patients with psychogenic seizures. Identical OCBs in serum and cerebrospinal fluid were more common in all patient groups (10-40% depending on underlying etiology). CONCLUSIONS: Intrathecal IgG synthesis/OCBs were observed slightly more frequently in patients with 'cryptogenic' epilepsy and with first seizures of unknown etiology than in other patient groups. However, this remained an infrequent finding and thus we could not confirm humoral immunity as a leading disease mechanism in patients with epilepsy in general or with unknown etiology in particular.

Increased blood-brain barrier permeability is associated with dementia and diabetes but not amyloid pathology or APOE genotype.

Blood-brain barrier (BBB) dysfunction might be an important component of many neurodegenerative disorders. In this study, we investigated its role in dementia using large clinical cohorts. The cerebrospinal fluid (CSF)/plasma albumin ratio (Qalb), an indicator of BBB (and blood-CSF barrier) permeability, was measured in a total of 1015 individuals. The ratio was increased in patients with Alzheimer's disease, dementia with Lewy bodies or Parkinson's disease dementia, subcortical vascular dementia, and frontotemporal dementia compared with controls. However, this measure was not changed during preclinical or prodromal Alzheimer's disease and was not associated with amyloid positron emission tomography or APOE genotype. The Qalb was increased in diabetes mellitus and correlated positively with CSF biomarkers of angiogenesis and endothelial dysfunction (vascular endothelial growth factor, intracellular adhesion molecule 1, and vascular cell adhesion molecule 1). In healthy elderly, high body mass index and waist-hip ratio predicted increased Qalb 20 years later. In summary, BBB permeability is increased in major dementia disorders but does not relate to amyloid pathology or APOE genotype. Instead, BBB impairment may be associated with diabetes and brain microvascular damage.

Quantitation of intrathecal immunoglobulin synthesis - a new empirical formula.

BACKGROUND AND PURPOSE: Intrathecal immunoglobulin (Ig) synthesis occurs in various chronic inflammatory neurological diseases. Different formulae have been developed for quantitative determination of Ig synthesis within the cerebrospinal fluid (CSF) compartment. The hyperbolic formula of Reiber is frequently used which, however, returns a considerable number of false positive results in empirical observations. METHODS: A computerized database of more than 19 000 paired CSF and serum samples was screened for patients presumed negative for local Ig synthesis and a new formula characterizing this collective was calculated. The validity of this formula was confirmed by several validation steps. RESULTS: A cohort of 1173 patients with normal CSF findings was used for quantile regression. The 97.5th quantile of the formula Qlim(IgX)=a×Qalbb was considered as the cut-off curve for intrathecal Ig synthesis using different constants a and b for IgG, IgA and IgM. Compared to the Reiber formula, a lower level of false positive results was produced especially for IgM and IgA which was confirmed in a separate clinically well defined validation cohort. In 77 patients with discrepant findings between Reiber and our formula no specific diagnoses were found confirming the low diagnostic value of borderline Ig synthesis. CONCLUSIONS: A new approximation formula was developed for determination of intrathecal Ig synthesis which produces fewer false positive results without reducing diagnostic sensitivity.

Label-Free LC-MS/MS Proteomic Analysis of Cerebrospinal Fluid Identifies Protein/Pathway Alterations and Candidate Biomarkers for Amyotrophic Lateral Sclerosis.

Analysis of the cerebrospinal fluid (CSF) proteome has proven valuable to the study of neurodegenerative disorders. To identify new protein/pathway alterations and candidate biomarkers for amyotrophic lateral sclerosis (ALS), we performed comparative proteomic profiling of CSF from sporadic ALS (sALS), healthy control (HC), and other neurological disease (OND) subjects using label-free liquid chromatography-tandem mass spectrometry (LC-MS/MS). A total of 1712 CSF proteins were detected and relatively quantified by spectral counting. Levels of several proteins with diverse biological functions were significantly altered in sALS samples. Enrichment analysis was used to link these alterations to biological pathways, which were predominantly related to inflammation, neuronal activity, and extracellular matrix regulation. We then used our CSF proteomic profiles to create a support vector machines classifier capable of discriminating training set ALS from non-ALS (HC and OND) samples. Four classifier proteins, WD repeat-containing protein 63, amyloid-like protein 1, SPARC-like protein 1, and cell adhesion molecule 3, were identified by feature selection and externally validated. The resultant classifier distinguished ALS from non-ALS samples with 83% sensitivity and 100% specificity in an independent test set. Collectively, our results illustrate the utility of CSF proteomic profiling for identifying ALS protein/pathway alterations and candidate disease biomarkers.

Influence of Allergy on Immunoglobulins and Amyloid-ß in the Cerebrospinal Fluid of Patients with Alzheimer's Disease.

BACKGROUND: Peripheral inflammation has been suggested to influence the development of Alzheimer's disease (AD). Elevated levels of pro-inflammatory markers in the plasma of patients with AD indicate that a systemic pro-inflammatory status occurs concomitantly with inflammatory changes in the brain. OBJECTIVE: To investigate whether allergy influences the levels of immunoglobulins (Ig) and of pro- and anti-inflammatory cytokines in the serum and cerebrospinal fluid (CSF) from patients with AD, mild cognitive impairment (MCI), and subjective cognitive impairment (SCI). METHODS: IgA, IgG, and its subclasses, IgM, and cytokines were analyzed in CSF and serum from patients with SCI, MCI, and AD, with or without allergy. The relation between allergy and Mini-Mental State Examination (MMSE) scores, and between allergy and CSF biomarkers for AD (phosphorylated (p)-tau, total (t)-tau, amyloid-ß 42 (Aß42), were analyzed. RESULTS: In MCI, the CSF levels of IgG2 were lower in allergic patients, and in AD, the levels of IgA and the IgG1/total IgG ratio were lower in allergic patients, compared to patients without allergy. MCI subjects with allergy had higher serum IgM levels compared to those without allergy. CSF levels of Aß42 were lower and MMSE scores were higher in AD patients with allergy than in those without allergy. CONCLUSIONS: The presence of allergy was associated with seemingly beneficial effects on AD as suggested by higher Aß42 levels in CSF, and higher MMSE scores. Higher IgM levels and lower other Ig classes suggest that allergy may influence senescence of the immune response.

Anti-NMDA Receptor Encephalitis in the Polar Bear (Ursus maritimus) Knut.

Knut the polar bear of the Berlin Zoological Garden drowned in 2011 following seizures and was diagnosed as having suffered encephalitis of unknown etiology after exhaustive pathogen screening. Using the diagnostic criteria applied to human patients, we demonstrate that Knut's encephalitis is almost identical to anti-NMDA receptor encephalitis which is a severe autoimmune disease representing the most common non-infectious encephalitis in humans. High concentrations of antibodies specific against the NR1 subunit of the NMDA receptor were detected in Knut's cerebrospinal fluid. Histological examination demonstrated very similar patterns of plasma cell infiltration and minimal neuronal loss in affected brain areas. We conclude that Knut suffered anti-NMDA receptor encephalitis making his the first reported non-human case of this treatable disease. The results suggest that anti-NMDA receptor encephalitis may be a disease of broad relevance to mammals that until now has remained undiagnosed.

Transient spurious intrathecal immunoglobulin synthesis in neurological patients after therapeutic apheresis.

BACKGROUND: The analysis of cerebrospinal fluid (CSF) is usually done under steady-state conditions, when proteins (e.g., immunoglobulins) reach diffusion equilibrium between blood and CSF. However, little data has been published on CSF analysis under non-steady-state conditions after therapeutic apheresis. By reducing serum proteins (e.g., immunoglobulins), while leaving CSF unchanged, therapeutic apheresis might cause spuriously altered intrathecal immunoglobulin fractions. METHODS: Based on the incidental finding of plasma exchange-induced increased intrathecal immunoglobulin fractions in a cohort of 12 unsystematically selected patients with various neurological disorders, we retrospectively investigated CSF results that had been raised during routine diagnostic work-up from 41 consecutive neurological patients (predominantly Guillain-Barré syndrome and autoimmune encephalitis) treated with plasmapheresis or immunoadsorption in a tertiary care university hospital in whom lumbar puncture (LP) was performed after a varying number of treatments of therapeutic apheresis. RESULTS: Only when LP was performed 1 day after therapeutic apheresis, spurious quantitative intrathecal immunoglobulin (Ig) synthesis of at least one subclass (IgG, IgA and/or IgM) was found in 68.4 % of the patients, irrespective of the number of treatments, in all age groups and independent of other previous immunotherapies (e.g., steroids). This phenomenon occurred only transiently and was almost always accompanied by an elevation of the IgG index. In one patient, an elevated IgG index was noticed even 2 days after plasmapheresis. Neither quantitative Ig synthesis, nor elevated IgG index was observed when the LP was performed three or more days after therapeutic apheresis. CONCLUSIONS: Spurious quantitative intrathecal Ig synthesis and increased IgG index are common findings shortly after plasmapheresis or immunoadsorption due to altered serum immunoglobulin levels. Knowledge of this phenomenon is needed for clinicians to prevent false interpretations leading to unnecessary diagnostic and therapeutic procedures. Misdiagnoses can be avoided by considering the characteristic CSF constellation including absence of oligoclonal bands and the close temporal relation to therapeutic apheresis.

Arachnoid involved in idiopathic hypertrophic pachymeningitis.

The cerebrospinal fluid (CSF) shows inflammatory changes in patients with idiopathic hypertrophic pachymeningitis (IHP), which is a rare disorder. However, systemic CSF research including immunoglobulins in patients with IHP are substantially lacking. In the study, clinical, laboratory, neuroradiologic and therapeutic data from 9 patients with IHP were retrospectively studied, and CSF changes were analyzed. Intracranial pressure was elevated in 4 patients. Protein levels in CSF were elevated in 5 patients (< 1g/L). IgA was elevated in 7 patients (> 0.5mg/dL), IgG was elevated in 8 patients (> 3.4 mg/dL) and IgM was elevated in 6 patients (>0.13 mg/dL) with IHP. CSF immunoglobulins, including IgA, IgG and IgM, were significantly elevated compared with levels in the control (P = 0.021, 0.018, 0.019). There were no linear correlations between IgG, IgM and protein in CSF, but there was a linear correlation between IgA and protein. In conclusion, CSF in IHP shows inflammatory changes, and protein levels are low to moderately elevated. CSF immunoglobulins, including IgA, IgG and IgM, also increased. The arachnoid is involved in IHP, a proportion of immunoglobulins may originate from the blood because of damage to the blood-CSF barrier at the arachnoid. Other intrathecal synthesis of immunoglobulins may be a secondary change due to alteration in the CSF's content to stabilize the internal environment or may be secreted by activated immune memory cells in the brain, which need further research.

Determination of Toll-like receptor-induced cytokine profiles in the blood and cerebrospinal fluid of Chikungunya patients.

BACKGROUND: Chikungunya infection caused by Chikungunya virus (CHIKV) is an inflammatory disease affecting the joints and may also lead to neurological complications. We investigated a panel of human Toll-like receptor (TLR)-induced cytokines in Chikungunya patients with and without neurological complications. METHODS: In a case-control study, a panel of 12 cytokines and chemokines, TNF-α, IFN-α, IL-1ß, IL-6, IL-12, IL-17A, IL-8, monocyte chemotactic protein (MCP)-1, RANTES, interferon (IFN)-γ-induced protein (IP)-10, monokine induced by IFN-γ (MIG) and thymus and activation-regulated chemokine (TARC), was analysed using a conventional ELISA protocol in the serum samples of Chikungunya patients without neurological complications and in the cerebrospinal fluid (CSF) and paired serum samples of Chikungunya patients with neurological complications. RESULTS: The levels of 3 cytokines, IL-1ß, IL-17A and IL-8, and 4 chemokines, MCP-1, RANTES, IP-10 and TARC, were raised in serum samples of Chikungunya patients without neurological complications, whereas, 4 cytokines, TNF-α, IFN-α, IL-6 and IL-8, and 4 chemokines, MCP-1, RANTES, MIG and TARC, were elevated in CSF samples of Chikungunya patients with neurological complications. Moreover, the levels of IL-6 and IL-8 cytokines were significantly elevated in the CSF compared to paired serum samples in Chikungunya patients with neurological complications. CONCLUSIONS: In CHIKV infection, multiple cytokines are elevated in serum and CSF. The elevation in IL-6 and IL-8 cytokines in CSF correlates with neurological involvement.

Cerebrospinal fluid analysis.

The cerebrospinal fluid (CSF) is a bodily fluid, which is both easily accessible and the most proximate to the pathological alterations of multiple sclerosis (MS). Consequently, the analysis of this fluid provides an important window into the pathological underpinnings of this disease. For example, for years, it has been known that the CSF of MS patients contains oligoclonal gamma immunoglobulins (IgG), which are synthesized within the central nervous system and presumably relate to the immune dysfunction, which is characteristically found in MS. This insight has lead to the introduction of highly-effective anti-B-cell therapies into the field of MS therapeutics. Moreover, the presence of an oligoclonal IgG response in the CSF, although not specific for MS, is a very sensitive finding and, as a result, its presence can be quite helpful for establishing an MS diagnosis in the right clinical context. In addition, this finding has predictive value. Thus, patients without a definite diagnosis who have CSF IgG bands are significantly more likely to develop definite MS compared to those patients without such a banding pattern. Other biological molecules can also be found in the CSF including neurofiliment, myelin basic protein (MBP), glial fibrillary acidic protein (GFAP), tau, neuronal cell adhesion molecule (NCAM), and the growth associated protein (GAP-43). However, the value of measuring these (and other) CSF constituents for both diagnostic and prognostic purposes and for following response to therapy is still to be determined.