The cerebrospinal fluid C4 complement component in different meningeal and neurological diseases

The C₄ complement component was measured in CSF from 10 patients without CNS involvement (controls) and 71 with various meningeal and neurological diseases.
Serum C₄ was also measured in the control group and in 46 of the 71 neurological patients.
A significant increase of CSF C₄ was observed in all neurological diseases with meningeal involvement independent of the causative agent. Inversely, serum C₄ values were within normal limits.
Increased CSF C₄ with normal serum levels might indicate increased diffusion across the blood-brain barrier, decreased ability for immuno-complex production or increased local production.     

Complement activation in the central nervous system following blood–brain barrier damage in man

The central nervous system (CNS) is virtually isolated from circulating immunological factors such as complment (C), an important mediator of humoral immunity and inflammation. In circulation, C i constantly inhibited to prevent attack on host cells. Since a host of diseases produce an abnormal blood–brain/cerebrospinal fluid (blood–brain/CSF) permeability allowing C protein extravasation, we investigated if C activation occurs in CSF in vitro and in CNS in vivo during subarachnoid hermorrhage (SAH) or brain infrarction. After SAH (n = 15), the terminal complement complex (TCC) concentration on days 0 to 2 was higher in the CSF, 210 ± 61 ng/ml, than in the plasma 63 ± 17 ng/ml, but null in the CSF of controls (n = 8) or patients with an ischemic stroke (n = 7). TCC was eliminated from the CSF after SAH (24 ± 10 ng/ml on days 7 to 10) Incubation of normal human CSF with serum in vitro also activated the terminal C pathway. In 10 fatal ischmemic brain infrarctions, immunohistochemical techniques demonstrated neuronal fragment-associated deposition of C9 accompanied by neutrophil infiltration. We conclude that the C system becomes activated intrathecally in SAH and focally in the brain parenchyma in ischemic stroke. By promoting chemotaxis and vascular perturbation, C activation may instigate nonimmune inflammation and aggravate CNS damage in diseases associated with plasma extravasation.     

Immunoglobulins and complement components in 37 patients infected by HIV-1 virus: comparison of general (systemic) and intrathecal immunity

Intrathecal (IT) immunity was assessed by simultaneous analysis of paired cerebrospinal fluid (CSF) and sera of 37 patients infected by human immunodeficiency virus-1 (HIV-1). Only 8 of these 37 patients had no neurological or neuropsychiatric symptoms. There were 3 prominent abnormalities observed: (1) IT IgA production occurred in 15 patients, IT IgM production in 14 patients, and IT IgG production in 34 patients. (2) IT Anti-HIV-1 antibody specific activity (ASA) was higher than in serum in 33 of the 37 patients indicating that IT synthesis of antibody specific for HIV-1 occurs even in asymptomatic patients; IT anti-HIV-1 antibody synthesis was not correlated with clinical severity or neurological involvement. IT anti-herpes simplex ASA was also higher than serum ASA in 6 patients indicating a possible associated herpes simplex virus infection. (3) IT production of the complement component C4 was found frequently and was highly correlated with increased serum C4. IT C3 levels were decreased in 21 of 37 patients indicating that complement activation is a frequent accompaniment of the IT immune response in HIV-1-positive patients. These results indicate a unique and localized IT immune response which is different from the pattern observed in the systemic immune compartment in HIV-1-seropositive individuals and from the pattern common to the other CNS infectious diseases.     

Complications of nervous system trauma: (Advances in neurology,vol. 22), by R. A. Thompson and J. R. Green (eds.), xii + 333 pages, 126 illustrations, 26 tables,Raven Press,New York,NY, 1979, US$ 38.35

Agarose isoelectric focusing (AIEF) of concentrated CSF was compared with AIEF of unconcentrated CSF and subsequent immunofixation with radiolabeled antihuman IgG Fc fragment antiserum and autoradiography for the demonstration of oligoclonal bands in CSF from 287 neurological patients. Oligoclonal bands were demonstrated by AIEF in 98% of 43 patients with multiple sclerosis, 72% of 18 patients with infectious CNS diseases, and 23% of 226 patients with other neurological diseases. The corresponding figures obtained with AIEF of unconcentrated CSF and radioimmunofixation were 98%, 67%, and 21%, respectively. In 15 of the patients, oligoclonal bands were demonstrated in CSF and serum by both techniques. They are both useful alternatives for the demonstration of oligoclonal bands in CSF, and the method for unconcentrated CSF can be safely applied when only small CSF volumes are available. The oligoclonal IgG pattern obtained by AIEF was not influenced by concentration of CSF by ultrafiltration and subsequent dilution to the original IgG concentration, nor by storage for 6 months.     

Ferritin concentration in cerebrospinal fluid

15 patients with psychosomatic disease, 26 patients with miscellaneous neurological diseases, and 16 patients with cerebrovascular disease were investigated with regard to concentrations of ferritin in serum and cerebrospinal fluid (CSF). The mean CSF ferritin concentration in the psychosomatic group was 6.2 micrograms/l +/- 2.4 (1 S.D.). Patients with recent cerebral infarction had similar values while 2 patients with intracerebral hematomas had very high CSF ferritin concentrations. There was a positive correlation between serum and CSF ferritin levels and between CSF total protein and ferritin in patients with a damaged blood-CSF barrier only. At present, the practical value of analysing ferritin in the CSF is very small.     

Intrathecal origin of CSF ribonuclease.

A CSF Poly(C)-avid ribonuclease (RNase) activity was determined in serum and CSF of 11 controls and 75 neurological patients (34 multiple sclerosis (MS), 18 infectious processes and 23 other neurological diseases (OND]. In controls, the blood-CSF ratio of RNase activity is low. This fact and the absence of correlation between serum and CSF RNase activity (except in OND group), and between CSF albumin and CSF RNase activity in controls and MS patients, suggest an intrathecal origin for the major part of this CSF RNase activity. A formula taking into account any plasmatic enrichment in RNase of the CSF is proposed to evaluate this intrathecal activity. The normal mean value of this intrathecal RNase activity is 27 +/- 3 units/ml (mean +/- SE) in our experimental conditions and using our formula. The highest intrathecal RNase activity is observed in infectious processes and this finding is associated with a significant increase in the local anti-RNA antibody synthesis. An increase in intrathecal RNase activity is rarely found in MS and local anti-RNA synthesis is only observed in one third of MS patients.     

Cerebrospinal fluid cells in multiple sclerosis and other neurological diseases: an immunocytochemical study

Summary Determinations of mononuclear cell subsets in cerebrospinal fluid (CSF), using monoclonal antibodies against surface antigens which identified pan T-cells, helper/inducer T-cells, cytotoxic/suppressor T-cells and Ia-positive cells, were performed in patients with multiple sclerosis (MS), other neuroimmunological diseases (NID), infectious diseases (INF) of the central nervous system and with other neurological diseases. Whereas there was an elevated helper T/suppressor T ratio in CSF of patients with NID (Guillain-Barré syndrome, chronic inflammatory demyelinating polyneuropathy, cerebral vasculitis), no other significant differences could be detected between the different groups of patients. Our results suggest that analysis of these mononuclear cell subsets in CSF is not helpful in discriminating between MS and other neurological diseases and that in MS patients changes in disease activity are not clearly indicated by fluctuations in the different CSF cell subsets. Further studies will be needed to confirm our findings in NID patients and to understand the diagnostic and theoretical implications.     

Frequency and relevance of IgM intrathecal synthesis in multiple sclerosis

Using a new ELISA method we have measured the IgM concentration in the serum and the cerebrospinal fluid CSF from 110 neurological patients. Among there, 41 had multiple sclerosis (MS), 48 other inflammatory diseases (OID), including 30 AIDS, and 21 non-inflammatory neurological diseases (NID). A highly significant correlation was established between results with native IgM and the dithiothreitol reduced IgM. An intrathecal synthesis (ITS) of IgM was detected using the CSF IgM/CSF albumin ratio, the IgM index and a quantitative formula in 33 patients: nine MS, 23 OID (including 18 AIDS) and one NID. The frequency of IgM ITS was 22% in MS patients, 48% in the OID (60% in AIDS) and 5% in the NID groups. This ITS was not impaired by an increase in serum IgM concentration or by a blood–CSF barrier damage. These facts confirm that intrathecal immunity is not a “steady-state” related to the general immunity but a specific response restricted to the central nervous system. Conversely, CSF IgM increase and IgM ITS were closely related (p < 10^?6). In addition, IgM ITS and IgG ITS were found to be highly correlated in OID, especially in AIDS patients: such correlation was not observed in the MS group. No significant correlations were observed between IgM ITS and any of the clinical parameters in MS patients. These results suggest the probable specificity of IgM ITS in MS patients.     

Terminal component of complement C9 in CSF and plasma of patients with MS and aseptic meningitis

A sensitive sandwich ELISA was applied to the measurement of the terminal component of complement C9 in CSF and plasma from 40 tension headache patients (reference group), 33 affected by clinically definite MS and 10 by aseptic meningitis. The levels of C9 in plasma were increased in aseptic meningitis. The determinations of CSF/plasma C9 ratio and C9 index, equal to (CSF C9/plasma C9): (CSF albumin/plasma albumin), thus accounting for changes of plasma C9 levels as well as damaged blood brain barrier, documented the existence of local consumption of C9 in aseptic meningitis. In contrast, only borderline alterations were evident in MS. The results indicate that local consumption of total C9 in CSF is an additional variable reflecting an acute inflammation within the CNS, but not demonstrable in MS, a chronic inflammatory CNS disorder.     

Increased concentration of C4d complement protein in CSF in amyotrophic lateral sclerosis.

Plasma and CSF concentrations of C4d and the circulating immune complex to C1q were measured in 27 patients with amyotrophic lateral sclerosis (ALS) or cervical spondylosis. There was no significant difference among groups in plasma C4d or in plasma or CSF concentrations of the circulating immune complex to C1q. The ALS group, however, had a significantly higher CSF concentration of C4d than the group with cervical spondylosis, as well as a higher C4d index (CSF to plasma C4d ratio x serum to CSF albumin ratio). These results suggest that augmented complement activation in the CNS occurs in ALS. Increased CSF concentration of C4d or raised C4d index may serve as a basis for differentiating ALS from cervical spondylosis.     

The intrathecal synthesis of virus-specific oligoclonal IgG in multiple sclerosis

A highly sensitive antigen-mediated capillary blot technique was developed for the detection of virus-specific oligoclonal IgG in paired CSF and serum samples from patients with various neurological diseases. In multiple sclerosis, intrathecal synthesis of oligoclonal antibodies was present against measles (70%), rubella (60%), varicella zoster (40%) and mumps (30%); in most cases (75%), such synthesis involved two or more viruses. In contrast, antibodies against a non-neurotropic virus (cytomegalovirus) were rarely produced in CSF from MS patients (5%). However, this ‘polyspecific’ reaction was not restricted to MS samples but was also observed in neurolupus and in the late phase of infectious diseases of the central nervous system. These anti-viral antibodies could be produced without de novo replication of the corresponding viral genome and are likely mere bystanders of an ongoing immune response.     

Intrathecal anti-αB-crystallin IgG antibody responses: Potential inflammatory markers in Guillain-Barré syndrome

OBJECTIVE: alphaB-crystallin (alphaBC), a small stress protein with cytoprotective and anti-apoptotic functions, is a potent antigen in autoimmune demyelinating diseases. To address the role of alphaBC in Guillain-Barré syndrome (GBS) we analyzed humoral responses against alphaBC in relation to clinical, electrophysiological and CSF features in GBS. METHODS: Anti-alphaBC-IgG antibodies were measured in serum and cerebrospinal fluid (CSF) of patients with GBS (n = 41), infectious inflammatory neurological diseases (n = 21), multiple sclerosis (n = 42), and other, non-inflammatory neurological disorders (n = 40) by ELISA using human recombinant alphaBC. Expression of alphaBC was immunohistochemically analyzed in postmortem peripheral nerve tissue of GBS and controls without neuropathy. RESULTS: Serum alphaBC-IgG antibody levels did not differ between disease groups, whereas alphaBC-IgG antibodies in CSF were increased in GBS and infectious inflammatory neurological diseases. Calculation of an antigen specific alphaBC-IgG index (alphaBC-Ig-G(CSF) x total IgG(CSF))/(alphaBC-IgG(Serum) x total IgG(Serum)) revealed significantly elevated values in patients with GBS compared to other disease groups (p < 0.001). alphaBC-IgG indices exceeding a cut off value > 0.8 had an 85 % specificity and a 76 % sensitivity for GBS. alphaBC was overexpressed in dorsal root ganglia and spinal roots of autopsy cases with GBS. CONCLUSIONS: We demonstrate increased alphaBC-IgG indices in a high proportion of our GBS patients, which reflect enhanced antigen-specific intrathecal antibody responses against abnormally expressed alphaBC in inflamed peripheral nerve tissue. Elevated alphaBC-IgG indices might therefore serve as markers of PNS inflammation and supplement currently used laboratory tests in the diagnosis of GBS.     

Elevation of Gas6 protein concentration in cerebrospinal fluid of patients with chronic inflammatory demyelinating polyneuropathy (CIDP)

INTRODUCTION: Gas6 enhances survival of Schwann cells and neurons in vitro and participates in autoimmunity in animal models. Since its concentration in human cerebrospinal fluid (CSF) is unknown, we measured it in samples from patients with non-inflammatory/non-autoimmune neurological diseases (NINAD) and autoimmune polyneuropathies. MATERIALS AND METHODS: Samples collected after informed consent during diagnostic lumbar puncture in the period 1999-2006 were stored at -30 degrees C. We considered subjects with NINAD (stroke, ALS, headache, psychiatric conditions simulating neurological diseases, otologic dizziness) or with Guillain-Barré syndrome (GBS) or CIDP. CSF and plasma total protein and age were obtained from clinical records. Gas6 was measured with an ELISA developed and validated in our laboratory (inter-, intra-assay CVs <10%, recovery 96%). Variance, Tukey's post-hoc test, regression were calculated with a statistical software (Statsoft). RESULTS: Mean Gas6 concentration in patients with NINAD was 6.5+/-2.4 ng/ml, 7.2+/-2.6 ng/ml in GBS and significantly higher (11.5+/-1.7 ng/ml) in CIDP than in the other conditions (post-hoc, p<0.005). It was not related to age, CSF total proteins or to CSF/plasma ratio of total proteins (regression, p>0.1). CONCLUSIONS: Gas6 is detectable in CSF and may be involved in chronic autoimmune demyelination or myelin repair.     

High cerebrospinal fluid concentration of glial fibrillary acidic protein (GFAP) in patients with normal pressure hydrocephalus

The concentration of glial fibrillary acidic protein (GFAP) in lumbar cerebrospinal fluid (CSF) was measured in 12 patients with normal pressure hydrocephalus (NPH) 11 patients with primary degenerative dementia (PDD), 8 patients with various other neurological diseases, and 18 patients without signs of organic nervous disease (controls).

Mean CSF GFAP concentration was significantly higher in NPH patients: 96 ± 23 ng/ml (SEM) when compared with PDD patients: 8.2 ± 1.9 ng/ml (P < 0.01), or with controls: 4.3 ± 0.7 ng/ml (P < 0.01). Only 2 NPH patients had a GFAP concentration within the range of the control group (2–14 ng GFAP/ml CSF). No significant differences were found between the PDD patients and the control group, or between the group of patients with other neurological diseases and the control group.

In addition, a rostro-caudal gradient of GFAP in CSF could be demonstrated. In 6 NPH and 2 PDD patients both ventricular and lumbar CSF samples were investigated. In all cases the ventricular GFAP concentration was higher than the lumbar concentration. The difference was statistically significant (P < 0.01).

Our results suggest that determination of CSF GFAP concentration might be of diagnostic value in discrimination between NPH patients and patients with enlarged ventricles associated with degenerative brain disease.     

Guillain-Barré syndrome: activated complement components C3a and C5a in CSF

Plasma and spinal fluid levels of complement activation products C3a and C5a were quantitated by radioimmunoassay in a group of 16 patients suffering from acute monophasic Guillain-Barré syndrome (GBS). Median CSF levels of C3a (118 ng/ml) and of C5a (9.6 ng/ml) were significantly elevated when compared with samples from a control group of patients with noninflammatory neurologic diseases. Plasma concentrations of these anaphylotoxic peptides were not significantly different between the two populations. Our findings indicate that the complement system is activated in the CSF of patients with acute GBS. Complement activation products may contribute to the inflammatory changes observed in this disorder.     

The cerebrospinal fluid concentrations of beta-glucuronidase and beta 2-microglobulin in neurological disorders

beta-Glucuronidase (beta-GL) and beta 2-microglobulin (beta 2-m) of the cerebrospinal fluid (CSF) were assayed from the patients with various neurological diseases, in order to evaluate the difference of mean value of these enzyme activities in several groups of neurological diseases, diagnostic usefulness for one of the central nervous system tumor markers, and the usefulness to differentiate carcinomatous meningitis from infectious meningitides. The subjects were 99 patients with various neurological diseases, and these were classified in the following eight diagnostic groups, central nervous system degenerative diseases (6 cases), cervical spondylotic radiculomyelopathy (15 cases), Guillain-Barre syndrome (8 cases), subarachnoid hemorrhage secondary to ruptured aneurysm (6 cases), infectious meningitides (21 cases), carcinomatous meningitis (9 cases), metastatic extradural spinal cord tumors (10 cases) and brain tumors (24 cases). CSF was also obtained from 13 subjects without any known neurological diseases for beta-GL and beta 2-m as the normal control values. beta-GL and beta 2-m were measured by Tsukamoto's method and the radioimmunoassay method (Phadebas, beta 2-m test) respectively. The statistical analyse were done by using the student t-test and expressed as p values. In the normal control group of 13 individuals without any obvious neurological diseases, the mean values +/- standard error of means (SEM) of beta-GL and beta 2-m were 122.5 +/- 10.8 micrograms/dl/hr, and 0.99 +/- 0.15 mg/l respectively.(ABSTRACT TRUNCATED AT 250 WORDS)     

A functional role for corpora amylacea based on evidence from complement studies

Few theories have been advanced for the production of corpora amylacea (CA) by the normal ageing brain and by the CNS under various neurological conditions. Proteins derived from neurons and oligodendrocytes are found in CA and to understand their origins brain tissue from patients with Alzheimer's disease (AD), multiple sclerosis (MS) and Pick's disease (PD) were tested for complement activity. All CA were immunopositive for antisera to classical pathway-specific components, the activation products C3d and the terminal complement complex (TCC), the C3 convertase regulator membrane cofactor protein (MCP) and the fluid phase regulators S-protein and clusterin. CA were immunonegative for the alternative complement pathway proteins and the complement regulators, decay accelerating factor (DAF) and CD59. Western immunoblotting of isolated solubilized CA from the same tissues demonstrated a week band for MCP but TCC was more easily shown by immunoprecipitaton. A filamentous fringe around CA, probably of astrocytic origin, was also immunopositive for complement factors. CA consist of an inert mucopolysaccharide matrix encasing ubiquitinated proteins, resulting from death of and damage to neurons, myelin and oligodendrocytes. A function of CA, therefore, could be to prevent the recognition of these immunogenic proteins by lymphocytes and microglia and thus protect the CNS from further injury.     

Determination of k/l immunoglobulin light chain ratios in CSF from patients with multiple sclerosis and other neurological diseases

Using antisera against Bence-Jones protein, the concentration of light chains type k and l can be determined in CSF. The calculation of the ratio of type k to type I light chains in CSF represents a sensitive measure for the evaluation of immunological processes involving the CNS. Our results demonstrate that an increase k/l ratio is encountered in 48% of CSF specimen from multiple sclerosis (MS) patients, but also in 50% from patients with other inflammatory diseases involving the CNS, in contrast to only 18% from other neurological diseases. In none of the MS or inflammatory cases is the altered k/l ratio the only indicator of a CNS inflammation, most commonly it is accompanied by an overproportional CSF-IgG elevation (increased QG ratio), an increased cell count or both. For these reasons determination of CSF k/l ratios is helpful in the differentiation of MS and other neurological diseases, but not for the differentiation of other inflammatory CNS diseases from MS.     

Arginine vasopressin concentrations in the cerebrospinal fluid of children

Cerebrospinal fluid (CSF) arginine vasopressin (AVP) levels are reported in a group of 22 children (median age 24 months) investigated for possible bacterial meningitis and subsequently found not to be suffering from this disease. The mean CSF AVP concentration was 0.80±0.33 pg/ml. The results obtained in patients suffering from febrile convulsions (mean 0.71 pg/ml), other convulsive disorders (mean 0.80 pg/ml) and miscellaneous infectious disease (mean 0.85 pg/ml) did not differ significantly from one another. Our findings confirm the presence of AVP in the CSF of children and provide reference values for further investigations into the functions of CSF AVP in children.     

Soluble immune complexes in cerebrospinal fluid of patients with multiple sclerosis and other neurological diseases

The occurrence of soluble immune complexes (IC) in the cerebrospinal fluid (CSF) of 14 multiple sclerosis (MS) patients, four acute polyradiculoneuritis patients, 30 patients with other neurological diseases (OND) and 30 patients with disc prolapse (DP) was examined by a solid phase C1q-protein A binding assay (C1q-PABA) and a complement consumption test. IC-positive reactions were observed only in the C1q-PABA. The binding indices determined by the C1q-PABA differed significantly ( P < 0.01) when the MS or the OND patient groups were compared to the DP group. No significant ( P < 0.1) difference was observed between the indices in the MS and OND groups. Binding indices in C1q-PABA showed no correlation either to IgG concentration, total protein concentration or cell counts in CSF of MS patients. Three of the four polyradiculoneuritis patients were strongly IC-positive while the fourth patient was negative. Filtration and PEG-precipitation data indicated that a major part of the IgG-containing IC in CSF detected by C1q-PABA was of macromolecular nature.