Increased intrathecal synthesis of fibronectin in bacterial and carcinomatous meningitis

Immunoreactive fibronectin (Fn) was quantified in paired cerebrospinal fluid (CSF) and serum samples from patients with bacterial meningitis (n = 46), tick-borne encephalitis (TBE) (n = 6), HIV infection (n = 6), Guillain-Barré syndrome (n = 5), carcinomatous meningitis (n = 11), multiple sclerosis (n = 15), disk disease (n = 11), and controls (n = 28). A highly significant elevation of CSF Fn was found in bacterial meningitis, TBE, and carcinomatous meningitis. There were no significant differences in serum Fn between any of the groups. An Fn index to estimate the rate of intrathecal Fn synthesis reached the highest value in bacterial meningitis. Our findings suggest that CSF Fn may be an indicator of adequate host reaction and tissue repair. For diagnostic purposes, the determination of CSF Fn probably does not add much to routine CSF laboratory tests.     

Interleukin-1β and tumor necrosis factor-α in cerebrospinal fluid of children with bacterial meningitis

Certain cytokines may contribute to the sequence of events that lead to meningeal inflammation in bacterial meningitis. The purpose of this study was to determine the levels of cytokines in the cerebrospinal fluid (CSF) of children with bacterial meningitis and aseptic meningitis of different etiologies. We determined the concentrations of interleukin-1beta (IL-1beta) and tumor necrosis factor (TNF-alpha) in the CSF of 171 specimens of 144 patients whose cases were classified as follow: bacterial meningitis (n=23), aseptic meningitis (n=26) and non-meningitis (n=95). The detectable IL-1beta concentration (> or =20 pg/ml) in the bacterial meningitis, aseptic meningitis and non-meningitis groups were observed with 78.3%, 3.8%, and 8.4%, respectively. Significantly higher serum IL-1beta concentrations were detected in those with bacterial meningitis than those with aseptic meningitis (538.93+/-605.32 pg/ml vs 2.52+/-11.57 pg/ml; P<0.001) or among non-meningitis subjects (2.90+/-11.91 pg/ml; P<0.001). The mean TNF-alpha concentration was 148.74+/-338.77 pg/ml. There was significantly more TNF-alpha than aseptic meningitis (6.85+/-17.93 pg/ml; P<0.001) or non-meningitis (7.67+/-16.07 pg/ml; P<0.001). With regard to diagnosis, measurement of IL-1beta and TNF-alpha levels showed sensitivities of 78% and 74%, respectively; specificities of 96% and 81%, respectively. It is suggested that the levels of these cytokines, especially IL-1beta and TNF-alpha, are useful markers for distinguishing bacterial meningitis from aseptic meningitis.     

LDH isoenzymes in cerebrospinal fluid in various brain tumours.

This study examined the isoenzymatic pattern of LDH in the cerebrospinal fluid (CSF) as well as the ratio between the five fractions of LDH among patients with various brain tumours, carcinomatous meningitis and control groups. LDH 1/LDH 2 less than 1 was found significant for carcinomatous meningitis (p less than 0.001) and brain metastases (p less than 0.001). LDH 1/LDH 2 ratio was found to be significantly lower in carcinomatous meningitis than in brain metastases (p less than 0.05). No LDH 1/LDH 2 ratios smaller than 1 were found in the other groups. The LDH 1/LDH 2 ratio smaller than 1 was found in the early stage of carcinomatous meningitis without other evidences of the involvement of the leptomeninges. Examination of LDH 1/LDH 2 can be found as an adjunctive method to identify brain metastases and carcinomatous meningitis at the initial stage.     

Soluble urokinase receptor (uPAR,CD 87) is present in serum and cerebrospinal fluid in patients with neurologic diseases

BACKGROUND: The receptor for urokinase plasminogen activator (uPAR) promotes invasion by neoplastic or inflammatory cells by focusing proteolysis of urokinase to the cell surface. In pathologic conditions, soluble forms of the receptor (suPAR) are released, and activate cell receptors to promote chemotaxis. In the CNS, suPAR and other components of the plasminogen activation system (PAS) could be associated with an increase of the blood-brain barrier (BBB) permeability and subsequent neural damage. OBJECTIVE: To detect suPAR in the serum and cerebrospinal fluid (CSF) of patients with diverse neurologic conditions. PATIENTS AND METHODS: Serum and CSF from 121 patients with cancer, bacterial and viral infection, stroke, demyelinating disease and peripheral neuropathy were examined for the presence of suPAR. RESULTS: suPAR was elevated in the serum of patients with paraneoplastic syndromes, and carcinomatous meningitis and infections, but less in stroke and demyelinating disease patients. CSF suPAR was present in the cancer and CNS infection groups, but not in the other groups. The levels of serum and CSF suPAR were correlated, and CSF suPAR correlated with the albumin index. CONCLUSIONS: suPAR is present in serum and CSF of patients with carcinomatous meningitis, paraneoplastic disorders and bacterial and viral infection of the CNS. suPAR could be associated with BBB disruption and with promotion of CNS invasion by chemotactically active cells, macromolecules, and microbes.     

Dexamethasone decreases cerebrospinal fluid soluble tumor necrosis factor receptor 1 levels in bacterial meningitis

It is known that the use of adjunctive dexamethasone in bacterial meningitis reduces audiologic and neurologic sequelae. The cerebrospinal fluid (CSF) level of soluble tumor necrosis factor 1 (sTNFR1) is an important indicator of neurologic sequelae in bacterial meningitis. We measured the CSF levels of IL-6 and sTNFR1 before administration of antibiotics (CSF1) and 1-3 days after administration of antibiotics (CSF2) in nine patients with bacterial meningitis who received dexamethasone sodium and five without dexamethasone. The CSF2 IL-6 levels of patients with/without dexamethasone were significantly lower than for CSF1 IL-6 levels (p = 0.0077, and p = 0.0431, respectively). There were no significant differences of the ratio of CSF2/CSF1 IL-6 levels between patients with dexamethasone and those without dexamethasone. CSF2 sTNFR1 levels of patients with dexamethasone were significantly lower than for CSF1 sTNFR1 levels (p = 0.0208). However, CSF2 sTNFR1 levels of patients without dexamethasone were significantly higher than for CSF1 sTNFR1 levels (p = 0.0422). The ratio of CSF2/CSF1 sTNFR1 levels of patients with dexamethasone was significantly lower than that without dexamethasone (p = 0.0063). Our present study suggests that dexamethasone inhibits increase of CSF sTNFR1 levels after antibiotics therapy in bacterial meningitis.     

NF-kappaB activation in cerebrospinal fluid cells from patients with meningitis

We examined whether or not NF-kappaB, a factor that regulates expression of the genes that code for pro-inflammatory cytokines, is activated in cerebrospinal fluid (CSF) cells to investigate the production of pro-inflammatory cytokines by CSF cells in patients with meningitis. Western blotting demonstrated that NF-kappaB was more activated in CSF cells of patients with bacterial meningitis than in those of patients with aseptic meningitis. NF-kappaB was hardly activated in carcinomatous meningitis. The NF-kappaB activation in CSF cells of patients with meningitis tended to be correlated with the CSF interleukin-6 concentration. Our data suggested that CSF cells produce pro-inflammatory cytokines through NF-kappaB activation in meningitis, and that increased NF-kappaB activation in CSF cells indicate infectious meningitis rather than carcinomatous meningitis.     

Level of transforming growth factor beta 1 is elevated in cerebrospinal fluid of children with acute bacterial meningitis

We investigated the levels of transforming growth factor beta 1 (TGF-β1) in cerebrospinal fluid (CSF) in children with meningitis, with a view to prognostic relevance. CSF TGF-β1 levels on admission were measured by a sandwich enzyme immunoassay in children with bacterial meningitis (n = 16), aseptic meningitis (n = 12), and control subjects without evidence of central nervous system (CNS) infection (n = 16). Patients were followed up for a mean duration of 13 months, and neurodevelopmental sequelae was determined for those with bacterial meningitis. On admission, CSF TGF-β1 levels were significantly higher in children with bacterial meningitis (mean, standard error, 32.92, 2.36 pg/ml) as opposed to those with aseptic meningitis (25.26, 1.72 pg/ml) (P = 0.0155), or control subjects (20.53, 1.05 pg/ml) (P < 0.0001). The CSF TGF-β1 levels in children with aseptic meningitis were higher than those in the control group, but without significance (P = 0.02). No apparent correlation existed between CSF TGF-β1 levels and CSF protein or cell counts in patients with bacterial meningitis. No significant difference in CSF TGF-β1 levels was found between patients with or without major sequelae following bacterial meningitis. Received: 19 March 1997 Received in revised form: 24 June 1997 Accepted: 20 August 1997     

NF-κB activation in cerebrospinal fluid cells from patients with meningitis

Abstract

We examined whether or not NF-κB, a factor that regulates expression of the genes that code for pro-inflammatory cytokines, is activated in cerebrospinal fluid (CSF) cells to investigate the production of pro-inflammatory cytokines by CSF cells in patients with meningitis. Western blotting demonstrated that NF-κB was more activated in CSF cells of patients with bacterial meningitis than in those of patients with aseptic meningitis. NF-κB was hardly activated in carcinomatous meningitis. The NF-κB activation in CSF cells of patients with meningitis tended to be correlated with the CSF interleukin-6 concentration. Our data suggested that CSF cells produce pro-inflammatory cytokines through NF-κB activation in meningitis, and that increased NF-κB activation in CSF cells indicate infectious meningitis rather than carcinomatous meningitis.     

Improved discrimination of AD patients using beta-amyloid(1-42) and tau levels in CSF.

OBJECTIVE: To evaluate CSF levels of beta-amyloid(1-42) (Abeta42) alone and in combination with CSF tau for distinguishing AD from other conditions. METHODS: At 10 centers in Europe and the United States, 150 CSF samples from AD patients were analyzed and compared with 100 CSF samples from healthy volunteers or patients with disorders not associated with pathologic conditions of the brain (CON), 84 patients with other neurologic disorders (ND), and 79 patients with non-Alzheimer types of dementia (NAD). Sandwich ELISA techniques were used on site for measuring Abeta42 and tau. RESULTS: Median levels of Abeta42 in CSF were significantly lower in AD (487 pg/mL) than in CON (849 pg/mL; p = 0.001), ND (643 pg/mL; p = 0.001), and NAD (603 pg/mL; p = 0.001). Discrimination of AD from CON and ND was significantly improved by the combined assessment of Abeta42 and tau. At 85% sensitivity, specificity of the combined test was 86% (95% CI: 81% to 91%) compared with 55% (95% CI: 47% to 62%) for Abeta42 alone and 65% (95% CI: 58% to 72%) for tau. The combined test at 85% sensitivity was 58% (95% CI: 47% to 69%) specific for NAD. The APOE e4 gene load was negatively correlated with Abeta42 levels not only in AD but also in NAD. CONCLUSIONS: The combined measure of CSF Abeta42 and tau meets the requirements for clinical use in discriminating AD from normal aging and specific neurologic disorders.     

Expression of vascular endothelial growth factor in tuberculous meningitis.

The pathogenesis of tuberculous meningitis is still unclear. Recently, vascular endothelial growth factor (VEGF) was found to be associated with inflammatory diseases and we found the increased serum level of VEGF in pulmonary tuberculosis. We hypothesized that VEGF might be associated with the pathogenesis of tuberculous meningitis and measured serum and cerebrospinal fluid (CSF) levels of VEGF in 28 patients with tuberculous meningitis and 31 non-tuberculous infectious meningitis patients (13 bacterial meningitis patients, eight fungal meningitis patients and 10 patients with viral meningitis) before therapy. We examined the CSF VEGF levels 3 months after in 12 tuberculous meningitis patients. The serum and CSF levels of VEGF were significantly higher in tuberculous meningitis than in other meningitis. The decrease in titer of CSF VEGF paralleled the clinical improvement of tuberculous meningitis. Immunohistochemical staining of autopsied brains demonstrated the presence of VEGF in the inflammatory mononuclear cells of the dense fibroconnective tissue both in the subarachnoid space and surrounding the vasculitis lesion. We found the expression of VEGF in tuberculous meningitis and think that VEGF reflects its activity.     

Vascular endothelial growth factor (VEGF) is increased in serum, but not in cerebrospinal fluid in HIV associated CNS diseases

Vascular endothelial growth factor (VEGF) is a potent angiogenic and mitogenic peptide, which also induces several mediators that may play a role in HIV induced CNS damage. VEGF levels were determined in cerebrospinal fluid (CSF) and serum samples from patients with (n = 8) and without (n = 19) directly HIV associated CNS disorders and HIV negative control patients (n = 18). VEGF serum but not CSF levels were significantly increased in HIV infected patients with (381.1 (78.9) pg/ml) HIV associated CNS diseases compared with those without (120.8 (13.1) pg/ml) and HIV negative control patients (133.1(14.8) pg/ml). Serum samples from patients with untreated HIV associated encephalopathy (HIVE, n = 3) contained the highest VEGF levels (583.9 (71.5) pg/ml). In two patients VEGF serum levels were reduced during antiretroviral therapy. However, regardless of effective viral suppression, patients with HIVE still had higher levels compared with HIV infected patients without HIVE. A relevant increase of serum VEGF was not observed in patients without HIVE though high HI viral load. We conclude that HIVE is associated with increased serum VEGF levels. Further studies are warranted to elucidate the role of VEGF in HIVE.     

CSF hypocretin/orexin levels in narcolepsy and other neurological conditions.

OBJECTIVE: To examine the specificity of low CSF hypocretin-1 levels in narcolepsy and explore the potential role of hypocretins in other neurologic disorders. METHODS: A method to measure hypocretin-1 in 100 microL of crude CSF sample was established and validated. CSF hypocretin-1 was measured in 42 narcolepsy patients (ages 16-70 years), 48 healthy controls (ages 22-77 years,) and 235 patients with various other neurologic conditions (ages 0-85 years). RESULTS: As previously reported, CSF hypocretin-1 levels were undetectably low (<100 pg/mL) in 37 of 42 narcolepsy subjects. Hypocretin-1 levels were detectable in all controls (224-653 pg/mL) and all neurologic patients (117-720 pg/mL), with the exception of three patients with Guillain-Barré syndrome (GBS). Hypocretin-1 was within the control range in most neurologic patients tested, including patients with AD, PD, and MS. Low but detectable levels (100-194 pg/mL) were found in a subset of patients with acute lymphocytic leukemia, intracranial tumors, craniocerebral trauma, CNS infections, and GBS. CONCLUSIONS: Undetectable CSF hypocretin-1 levels are highly specific to narcolepsy and rare cases of GBS. Measuring hypocretin-1 levels in the CSF of patients suspected of narcolepsy is a useful diagnostic procedure. Low hypocretin levels are also observed in a large range of neurologic conditions, most strikingly in subjects with head trauma. These alterations may reflect focal lesions in the hypothalamus, destruction of the blood brain barrier, or transient or chronic hypofunction of the hypothalamus. Future research in this area is needed to establish functional significance.     

Antibody neutralization of vascular endothelial growth factor (VEGF) fails to attenuate vascular permeability and brain edema in experimental pneumococcal meningitis

To determine the contribution of vascular endothelial growth factor (VEGF) to cerebral edema formation in bacterial meningitis, we used a VEGF neutralizing antibody to block VEGF in rabbits, following induction of meningitis by intracisternal inoculation with 10⁹ heat-killed pneumococci. At 8 h, cerebrospinal fluid (CSF) VEGF was significantly elevated in infected untreated animals, and correlated with CSF white blood cell (WBC) count (r=0.56, P=0.004), and brain water content (r=0.42, P=0.04). Blocking of VEGF did not attenuate brain edema, blood–brain barrier disruption, or CSF pleocytosis. The functional role of VEGF in the pathophysiology of BM remains elusive.     

Role of the urokinase plasminogen activator system in patients with bacterial meningitis

BACKGROUND: The urokinase plasminogen activator system has the potency to promote leukocyte recruitment and blood-CSF barrier breakdown, and thus may play an important pathophysiologic role in bacterial meningitis. METHODS: CSF and serum concentrations of urokinase-plasminogen activator (urokinase [uPA]), uPA receptor (uPAR), and PA inhibitor-1 (PAI-1) were quantified by ELISA in 12 patients with bacterial meningitis, control patients (n = 10) with noninflammatory neurologic diseases, and 10 patients with Guillain-Barré syndrome (GBS), a disease in which blood-CSF barrier disruption occurs without CSF pleocytosis. Casein zymography was used to determine PA-dependent plasminogen activation in the CSF. RESULTS: A marked increase in uPA-dependent plasminogen activation was detected in the CSF of patients with bacterial meningitis vs CSF of patients with GBS and controls. Accordingly, ELISA analysis of CSF revealed intrathecal upregulation of uPA protein in patients with bacterial meningitis. CSF concentrations of uPAR and PAI-1 were also elevated in these patients. The serum of patients with bacterial meningitis showed elevated protein levels of uPA, but not uPAR or PAI-1. Positive correlations were found between blood-CSF barrier breakdown and CSF uPA concentrations, and between CSF pleocytosis and CSF/serum ratios of the potent chemokine uPAR in patients with bacterial meningitis. Furthermore, an adverse clinical outcome in these patients correlated with serum uPA concentrations. CONCLUSION: In bacterial meningitis, the urokinase plasminogen activator system is involved in leukocyte recruitment and breaching of the blood-CSF barrier, and this may contribute to an unfavorable clinical outcome.     

Soluble CD40 and soluble CD40L concentrations in the serum and the cerebrospinal fluid of patients with tick borne encephalitis and neuroborreliosis

BACKGROUND AND PURPOSE: The interaction between CD40 and CD40L is essential in generating of an immunological response also intrathecally. The aim of the study was estimation of a concentration soluble form of CD40, CD40L (CD154) in the bacterial and viral inflammation of the central nervous system in two compartments - blood circulation and intrathecally, before and after the treatment. MATERIAL AND METHODS: sCD40 and sCD40L were tested twice before and after treatment in pairs serum and CSF of 40 patients treated in the Dept. of Infectious Diseases and Neuroinfections. Patients were divided in two groups: (n=20) patients with tick borne encephalitis (TBE) (group I, n=20) and patients with neuroborreliosis in the form of lymphocytic meningitis (group II, n=20). ELISA assays were performed. RESULTS: Significantly increased concentrations of sCD40, sCD40L in CSF (higher in neuroborreliosis) were measured. We found also an increased concentration of sCD40L in inflammatory CSF in both tested groups (in neuroboreliosis lasting also after 4 weeks of treatment), compared with the control group (below the detection limit in normal CSF). CONCLUSIONS: Results of estimation of the sCD40 and sCD40L concentrations indicate their role in the intrathecal inflammation process of bacterial and viral etiology. The increased serum concentration of sCD40L in TBE and CD40 in neuroborreliosis indicate that peripheral activation of the immunological system persists after cessation of treatment and after the clinical recovery. The defense mechanisms are more pronounced in neuroborreliosis than in tick borne encephalitis.     

Blood-brain barrier function in cerebral malaria and CNS infections in Vietnam

BACKGROUND: The intraerythrocytic parasite Plasmodium falciparum induces the life-threatening neurologic syndrome of cerebral malaria (CM) from within cerebral blood vessels, without entering the brain parenchyma. OBJECTIVES: 1) To assess the use of CSF as an indicator of specific pathologic processes occurring in the brain during CM; 2) to compare this with other neurologic and infectious diseases to understand the distinct pathogenic features of CM; 3) to test the hypothesis that CM involves a specific functional breakdown of the blood-brain barrier (BBB). METHODS: 1) Radial immunodiffusion assays to detect albumin and IgG in matched plasma and CSF samples as indicators of BBB integrity and intrathecal IgG production; and 2) ELISA for soluble intracellular adhesion molecule-1 and sE-selectin, the cytokines tumor necrosis factor-alpha and transforming growth factor-beta1, and the matrix metalloproteinase MMP-9, to detect cellular activation and inflammatory responses within the brain. RESULTS: Albumin and IgG indices implied only minimal degree of BBB breakdown in a few cases of CM, with most remaining within the normal range. In contrast, cryptococcal, tubercular, and acute bacterial meningitis produced detectable changes in the composition of the CSF and evidence of BBB breakdown. CONCLUSIONS: CM appears to involve only subtle functional changes in BBB integrity with minimal intraparenchymal inflammatory responses compared with other neurologic infections. This focuses attention on local events within and around the cerebral microvasculature in CM, rather than indicating widespread parenchymal disease.     

Endogenous melatonin increases in cerebrospinal fluid of patients after severe traumatic brain injury and correlates with oxidative stress and metabolic disarray

Oxidative stress plays a significant role in secondary damage after severe traumatic brain injury (TBI); and melatonin exhibits both direct and indirect antioxidant effects. Melatonin deficiency is deleterious in TBI animal models, and its administration confers neuroprotection, reducing cerebral oedema, and improving neurobehavioural outcome. This study aimed to measure the endogenous cerebrospinal fluid (CSF) and serum melatonin levels post-TBI in humans and to identify relationships with markers of oxidative stress via 8-isoprostaglandin-F2alpha (isoprostane), brain metabolism and neurologic outcome. Cerebrospinal fluid and serum samples of 39 TBI patients were assessed for melatonin, isoprostane, and various metabolites. Cerebrospinal fluid but not serum melatonin levels were markedly elevated (7.28+/-0.92 versus 1.47+/-0.35 pg/mL, P<0.0005). Isoprostane levels also increased in both CSF (127.62+/-16.85 versus 18.28+/-4.88 pg/mL, P<0.0005) and serum (562.46+/-50.78 versus 126.15+/-40.08 pg/mL (P<0.0005). A strong correlation between CSF melatonin and CSF isoprostane on day 1 after injury (r=0.563, P=0.002) suggests that melatonin production increases in conjunction with lipid peroxidation in TBI. Relationships between CSF melatonin and pyruvate (r=0.369, P=0.049) and glutamate (r=0.373, P=0.046) indicate that melatonin production increases with metabolic disarray. In conclusion, endogenous CSF melatonin levels increase after TBI, whereas serum levels do not. This elevation is likely to represent a response to oxidative stress and metabolic disarray, although further studies are required to elucidate these relationships.     

Cerebrospinal fluid ferritin levels in screening for meningism

To evaluate the potential diagnostic value of the ferritin concentration in cerebrospinal fluid (CSF), measurements were performed with an immunoradiometric assay in 23 control patients and in 65 patients with various neurologic disorders. The geometric mean ferritin level of 3.5 micrograms/L in controls was approximately 10% of the level in normal serum with an upper cutoff level of 10 micrograms/L. Only modest elevations in CSF ferritin concentration were observed in patients with viral meningitis and in those with various non-infectious neurologic disorders. On the other hand, marked elevations ranging between 27 and 322 micrograms/L (geometric mean, 90 micrograms/L) were observed in patients with bacterial or fungal meningitis. Results of the study indicate that CSF ferritin levels are a valuable adjunct in the early evaluation of patients presenting with meningism.     

Glutamine synthetase in cerebrospinal fluid, serum, and brain: a diagnostic marker for Alzheimer disease?

OBJECTIVES: To determine whether the glutamine synthetase (GS) level in cerebrospinal fluid (CSF) is a useful biochemical marker in the diagnosis of Alzheimer disease (AD), and to assess the source of GS (brain vs. blood derived) in CSF. METHODS: Sandwich enzyme immunoassay and immunoblotting were applied to detect GS in CSF and in serum from neurologically healthy control subjects and patients with neurodegenerative diseases, including AD. The origin of GS was estimated by the concentration gradients of CSF to serum and ventricular to lumbar CSF. In addition, postmortem brain tissue from controls and patients with AD was analyzed using immunohistochemistry for expression of GS. RESULTS: Levels of GS were significantly increased in lumbar CSF from patients with AD (20+/-12 pg/mL; P = .01) and to a lesser extent in patients with vascular dementia and amyotrophic lateral sclerosis. In CSF of controls, GS levels were 4+/-3 pg/mL. The GS concentration gradients were less than 1:10 for CSF to serum and 2:1 for ventricular to lumbar CSF. Immunoreactivity of GS was most prominent in astrocytes from temporal neocortex of patients with AD, suggesting a relationship between astrocyte reactions and increased GS levels in CSF. CONCLUSIONS: Level of GS in lumbar CSF of patients with AD is increased significantly but nonspecifically, probably related to the strong astrogliosis in brain. Glutamine synthetase in lumbar CSF is mainly brain derived.     

Free amino acid pattern of cerebrospinal fluid in meningeal pathology

Free amino acid concentrations of CSF were measured in bacterial meningitis, aseptic meningitis, meningoradiculitis Garin-Bujadoux-Bannwarth, multiple sclerosis, carcinomatous meningitis, and controls. Almost all CSF amino acids were highly elevated in bacterial but not in aseptic meningitis, meningoradiculitis Garin-Bujadoux-Bannwarth or carcinomatous meningitis thus providing a laboratory tool for their differential diagnosis. In carcinomatous meningitis the amino acid pattern indicates metabolic activity of tumor cells. Minimal alterations were found in multiple sclerosis which have no diagnostic value.