CSF and serum orosomucoid (alpha-1-acid glycoprotein) in patients with multiple sclerosis: a comparison among particular subgroups of MS patients

Orosomucoid-1 Arises as a Shared Altered Protein in Two Models of Multiple Sclerosis

Multiple sclerosis (MS) is a complex autoimmune and neurodegenerative disorder that affects the central nervous system (CNS). It is characterized by a heterogeneous disease course involving demyelination and inflammation. In this study, we utilized two distinct animal models, cuprizone (CPZ)-induced demyelination and experimental autoimmune encephalomyelitis (EAE), to replicate various aspects of the disease. We aimed to investigate the differential CNS responses by examining the proteomic profiles of EAE mice during the peak disease (15 days post-induction) and cuprizone-fed mice during the acute phase (38 days). Specifically, we focused on two different regions of the CNS: the dorsal cortex (Cx) and the entire spinal cord (SC). Our findings revealed varied glial, synaptic, dendritic, mitochondrial, and inflammatory responses within these regions for each model. Notably, we identified a single protein, Orosomucoid-1 (Orm1), also known as Alpha-1-acid glycoprotein 1 (AGP1), that consistently exhibited alterations in both models and regions. This study provides insights into the similarities and differences in the responses of these regions in two distinct demyelinating models.

Identification of Potential Drug Targets for Antiplatelet Therapy Specifically Targeting Platelets of Old Individuals through Proteomic Analysis

Aging is a growing problem worldwide, and the prevalence and mortality of arterial and venous thromboembolism (VTE) are higher in the elderly than in the young population. To address this issue, various anticoagulants have been used. However, no evidence can confirm that antithrombotic agents are suitable for the elderly. Therefore, this study aims to investigate the platelet proteome of aged mice and identify antithrombotic drug targets specific to the elderly. Based on the proteome analysis of platelets from aged mice, 308 increased or decreased proteins were identified. Among these proteins, three targets were selected as potential antithrombotic drug targets. These targets are membrane proteins or related to platelet function and include beta-2-glycoprotein 1 (β2GP1, ApolipoproteinH (ApoH)), alpha-1-acid glycoprotein2 (AGP2, Orosomucoid-2 (Orm2)), and Ras-related protein (Rab11a).

Proteomics in Multiple Sclerosis: The Perspective of the Clinician

Multiple sclerosis (MS) is the inflammatory demyelinating and neurodegenerative disease of the central nervous system (CNS) that affects approximately 2.8 million people worldwide. In the last decade, a new era was heralded in by a new phenotypic classification, a new diagnostic protocol and the first ever therapeutic guideline, making personalized medicine the aim of MS management. However, despite this great evolution, there are still many aspects of the disease that are unknown and need to be further researched. A hallmark of these research are molecular biomarkers that could help in the diagnosis, differential diagnosis, therapy and prognosis of the disease. Proteomics, a rapidly evolving discipline of molecular biology may fulfill this dire need for the discovery of molecular biomarkers. In this review, we aimed to give a comprehensive summary on the utility of proteomics in the field of MS research. We reviewed the published results of the method in case of the pathogenesis of the disease and for biomarkers of diagnosis, differential diagnosis, conversion of disease courses, disease activity, progression and immunological therapy. We found proteomics to be a highly effective emerging tool that has been providing important findings in the research of MS.

Dasatinib and dexamethasone followed by hematopoietic cell transplantation for adults with Ph-positive ALL

Dasatinib and dexamethasone induction then allogeneic hematopoietic cell transplantation was feasible and effective for untreated Ph⁺ ALL.

Treatment failure was associated with BCR-ABL1 T315I mutation, the p210 BCR-ABL1 isoform, or isolated CNS relapse.

Post-remission strategies after dasatinib-corticosteroid induction in adult Philadelphia chromosome (Ph)–positive acute lymphoblastic leukemia (ALL) are not well studied. We evaluated dasatinib and dexamethasone induction then protocol-defined post-remission therapies, including hematopoietic cell transplantation (HCT). Adults (N = 65) with Ph-positive ALL received dasatinib-dexamethasone induction, methotrexate-based central nervous system (CNS) prophylaxis, reduced-intensity conditioning (RIC) allogeneic HCT, autologous HCT, or chemotherapy alone, and dasatinib-based maintenance. Key end points were disease-free survival (DFS) and overall survival (OS). The median age was 60 years (range, 22-87 years). The complete remission rate was 98.5%. With a median follow-up of 59 months, 5-year DFS and OS were 37% (median, 30 months) and 48% (median, 56 months), respectively. For patients receiving RIC allogeneic HCT, autologous HCT, or chemotherapy, 5-year DFS were 49%, 29%, and 34%, and 5-year OS were 62%, 57%, and 46%, respectively. Complete molecular response rate after CNS prophylaxis was 40%. Relative to the p190 isoform, p210 had shorter DFS (median 10 vs 34 months, P = .002) and OS (median 16 months vs not reached, P = .05). Relapse occurred in 25% of allogeneic HCT, 57% of autologous HCT, and 36% of chemotherapy patients. T315I mutation was detected in 6 of 8 marrow relapses. Dasatinib CNS concentrations were low. Dasatinib-dexamethasone followed by RIC allogeneic HCT, autologous HCT, or chemotherapy was feasible and efficacious, especially with RIC allogeneic HCT. Future studies should address the major causes of failure: T315I mutation, the p210 BCR-ABL1 isoform, and CNS relapse. This study was registered at www.clinicaltrials.gov as #NCT01256398.

Cerebrospinal fluid exposure to bictegravir/emtricitabine/tenofovir in HIV-1-infected patients with CNS impairment

OBJECTIVES

The penetration of antiretroviral drugs into deep compartments, such as the CNS, is a crucial component of strategies towards an HIV cure. This study aimed to determine CSF concentrations of bictegravir, emtricitabine and tenofovir in patients with HIV-related CNS impairment (HCI) enrolled in a real-life observational study.

METHODS

Patients with HCI treated by optimized ART, including bictegravir/emtricitabine/tenofovir alafenamide (BIC/FTC/TAF) for at least 1 month were enrolled. Plasma and CSF concentrations were measured by quality control-validated assays (LC-MS/MS). The inhibitory quotient (IQARV) was calculated as the ratio of unbound (bictegravir) or total (emtricitabine and tenofovir) concentration to half (or 90%) maximal inhibitory concentration for bictegravir (or emtricitabine and tenofovir). All numerical variables are expressed as median (range).

RESULTS

Twenty-four patients (nine women) were enrolled. The age was 45 (26-68) years. Unbound bictegravir and total emtricitabine and tenofovir CSF concentrations were 4.4 (1.6-9.6), 84.4 (28.6-337.4) and 1.6 (0.7-4.3) ng/mL, respectively. The unbound bictegravir CSF fraction was 34% (15%-82%) versus 0.33% (0.11%-0.92%) in plasma. Three patients had an IQARV above unity for the three antiretrovirals. Factors positively associated with the CSF concentration (unbound for bictegravir) were age and total plasma concentration for the three antiretrovirals. Patients aged over 51 years had higher CSF concentrations (unbound for bictegravir).

CONCLUSIONS

We observed low CSF exposure to bictegravir, emtricitabine and tenofovir. These results suggest that BIC/FTC/TAF should be used with caution as first-line treatment for people living with HIV with HCI under 51 years of age.

Localisation of clozapine during experimental autoimmune encephalomyelitis and its impact on dopamine and its receptors

Multiple sclerosis is a disease characterised by axonal demyelination in the central nervous system (CNS). The atypical antipsychotic drug clozapine attenuates experimental autoimmune encephalomyelitis (EAE), a mouse model used to study multiple sclerosis, but the precise mechanism is unknown and could include both peripheral and CNS-mediated effects. To better understand where clozapine exerts its protective effects, we investigated the tissue distribution and localisation of clozapine using matrix-assisted laser desorption ionization imaging mass spectrometry and liquid chromatography-mass spectrometry. We found that clozapine was detectable in the brain and enriched in specific brain regions (cortex, thalamus and olfactory bulb), but the distribution was not altered by EAE. Furthermore, although not altered in other organs, clozapine levels were significantly elevated in serum during EAE. Because clozapine antagonises dopamine receptors, we analysed dopamine levels in serum and brain as well as dopamine receptor expression on brain-resident and infiltrating immune cells. While neither clozapine nor EAE significantly affected dopamine levels, we observed a significant downregulation of dopamine receptors 1 and 5 and up-regulation of dopamine receptor 2 on microglia and CD4+-infiltrating T cells during EAE. Together these findings provide insight into how neuroinflammation, as modelled by EAE, alters the distribution and downstream effects of clozapine.

Different glycoforms of alpha-1-acid glycoprotein contribute to its functional alterations in platelets and neutrophils

Alpha-1-acid glycoprotein (AGP-1) is a positive acute phase glycoprotein with uncertain functions. Serum AGP-1 (sAGP-1) is primarily derived from hepatocytes and circulates as 12-20 different glycoforms. We isolated a glycoform secreted from platelet-activating factor (PAF)-stimulated human neutrophils (nAGP-1). Its peptide sequence was identical to hepatocyte-derived sAGP-1, but nAGP-1 differed from sAGP-1 in its chromatographic behavior, electrophoretic mobility, and pattern of glycosylation. The function of these 2 glycoforms also differed. sAGP-1 activated neutrophil adhesion, migration, and neutrophil extracellular traps (NETosis) involving myeloperoxidase, peptidylarginine deiminase 4, and phosphorylation of ERK in a dose-dependent fashion, whereas nAGP-1 was ineffective as an agonist for these events. Furthermore, sAGP-1, but not nAGP-1, inhibited LPS-stimulated NETosis. Interestingly, nAGP-1 inhibited sAGP-1-stimulated neutrophil NETosis. The discordant effect of the differentially glycosylated AGP-1 glycoforms was also observed in platelets where neither of the AGP-1 glycoforms alone stimulated aggregation of washed human platelets, but sAGP-1, and not nAGP-1, inhibited aggregation induced by PAF or ADP, but not by thrombin. These functional effects of sAGP-1 correlated with intracellular cAMP accumulation and phosphorylation of the protein kinase A substrate vasodilator-stimulated phosphoprotein and reduction of Akt, ERK, and p38 phosphorylation. Thus, the sAGP-1 glycoform limits platelet reactivity, whereas nAGP-1 glycoform also limits proinflammatory actions of sAGP-1. These studies identify new functions for this acute phase glycoprotein and demonstrate that the glycosylation of AGP-1 controls its effects on 2 critical cells of acute inflammation.

Recommendations for cerebrospinal fluid analysis

Diseases of the central nervous system (CNS) mean for the human organism a potentially dangerous situation. An investigation of cerebrospinal fluid (CSF) provides important information about a character of CNS impairment in the decision-making diagnostic and therapeutic algorithm. The authors present a brief overview of available cerebrospinal fluid assays, shortened indication criteria, a recommended algorithm of CSF assessment in different suspected diseases, and a view of the external quality system. The whole portfolio of obtainable CSF methodology is further subdivided according to the adequate choice into the first and inevitable basic routine panel, and following complicated analyses of highly specialized character. The basic panel is considered for standard laboratories, the complete specialized assessment should be provided by a super-consulting laboratory.

Changes of cerebrospinal fluid protein concentrations and gait patterns in geriatric normal pressure hydrocephalus patients after ventriculoperitoneal shunting surgery

Normal pressure hydrocephalus (NPH) was the first type of dementia ever described that can be treated using ventriculoperitoneal shunting surgery. Three typical clinical symptoms of NPH include gait disturbance, progressive cognitive dysfunction, and urinary incontinence. Although there are articles that have discovered several cerebrospinal fluid (CSF) protein biomarkers associated with NPH; however, studies examining individual and total protein concentrations from the ventricular CSF before and after shunting surgery are lacking. This study used proteomics to calculate the CSF individual and total protein concentrations before, and one week, one month and three months after the shunting surgery. Parameters of cadence, step length, walking speed, and percentages of single- and double-limb support in a gait cycle were measured. Protein concentrations associated with anti-oxidation, aging, and in the prevention of neurotoxic agent production increased by at least 2-folds after the surgery, indicating that the brain may become less susceptible to neurodegeneration. These proteins were alpha-1B-glycoprotein, apolipoproteins A-1 & A-IV, prostaglandin-H2 D-isomerase, alpha-1-antitrypsin, and serotransferrin. In gait analysis, lower cadence, decreased double-limb support, longer step length, and increased single-limb support were observed after the surgery, indicating a more stable walking balance. These changes lasted for a period of at least 3 months. As a result, shunting surgery may be recommended for geriatric patients with confirmed diagnosis of normal pressure hydrocephalus.

ING116070: a study of the pharmacokinetics and antiviral activity of dolutegravir in cerebrospinal fluid in HIV-1-infected, antiretroviral therapy-naive subjects

Median dolutegravir concentrations in cerebrospinal fluid were similar to unbound concentrations in plasma and all subjects exceeded the in vitro 50% inhibitory concentration for wild-type viruses (0.2 ng/mL) by ≥66-fold, suggesting therapeutic concentrations are achieved in cerebrospinal fluid..

Background. Dolutegravir (DTG), a once-daily, human immunodeficiency virus type 1 (HIV-1) integrase inhibitor, was evaluated for distribution and antiviral activity in cerebrospinal fluid (CSF).

Methods. ING116070 is an ongoing, single-arm, open-label, multicenter study in antiretroviral therapy–naive, HIV-1–infected adults. Subjects received DTG (50 mg) plus abacavir/lamivudine (600/300 mg) once daily. The CSF and plasma (total and unbound) DTG concentrations were measured at weeks 2 and 16. The HIV-1 RNA levels were measured in CSF at baseline and weeks 2 and 16 and in plasma at baseline and weeks 2, 4, 8, 12, and 16.

Results. Thirteen white men enrolled in the study; 2 withdrew prematurely, 1 because of a non–drug-related serious adverse event (pharyngitis) and 1 because of lack of treatment efficacy. The median DTG concentrations in CSF were 18 ng/mL (range, 4–23 ng/mL) at week 2 and 13 ng/mL (4–18 ng/mL) at week 16. Ratios of DTG CSF to total plasma concentration were similar to the unbound fraction of DTG in plasma. Median changes from baseline in CSF (n = 11) and plasma (n = 12) HIV-1 RNA were −3.42 and −3.04 log₁₀ copies/mL, respectively. Nine of 11 subjects (82%) had plasma and CSF HIV-1 RNA levels <50 copies/mL and 10 of 11 (91%) had CSF HIV-1 RNA levels <2 copies/mL at week 16.

Conclusions. The DTG concentrations in CSF were similar to unbound plasma concentrations and exceeded the in vitro 50% inhibitory concentration for wild-type HIV (0.2 ng/mL), suggesting that DTG achieves therapeutic concentrations in the central nervous system. The HIV-1 RNA reductions were similar in CSF and plasma.

Clinical Trials Registration. NCT01499199.

Darunavir is predominantly unbound to protein in cerebrospinal fluid and concentrations exceed the wild-type HIV-1 median 90% inhibitory concentration

OBJECTIVES

Higher CSF antiretroviral concentrations may be associated with better control of HIV replication and neurocognitive performance, but only the unbound fraction of antiretrovirals is available to inhibit HIV. Therefore, the objective of this study was to determine total and unbound darunavir concentrations in CSF and compare findings with plasma concentrations as well as the wild-type HIV-1 90% inhibitory concentration (IC(90)).

METHODS

Subjects with HIV infection were selected based on the use of darunavir-containing regimens with a twice-daily dosing schedule and availability of stored CSF and matched plasma. Total darunavir was measured by HPLC for plasma or liquid chromatography-tandem mass spectroscopy (LC/MS/MS) for CSF. Plasma unbound darunavir was measured by ultrafiltration and LC/MS/MS. CSF protein binding was determined by competitive binding exchange with radiolabelled darunavir.

RESULTS

Twenty-nine matched CSF-plasma pairs were analysed and darunavir was detected in all CSF specimens (median total concentration 55.8 ng/mL), with a CSF unbound fraction of 93.5%. Median fractional penetrance was 1.4% of median total and 9.4% of median unbound plasma concentrations. Unbound darunavir concentrations in CSF exceeded the median IC(90) for wild-type HIV in all subjects by a median of 20.6-fold, despite the relatively low fractional penetrance. Total darunavir concentrations in CSF correlated with both total and unbound darunavir concentrations in plasma.

CONCLUSIONS

Darunavir should contribute to the control of HIV replication in the CNS as a component of effective combination antiretroviral regimens.

Myelin basic protein immunosensor for multiple sclerosis detection based upon label-free electrochemical impedance spectroscopy

A novel highly sensitive impedimetric Myelin Basic Protein (MBP) immunosensor for the determination of a Multiple Sclerosis (MS) autoantibody, Anti-Myelin Basic Protein (Anti-MBP) was developed by immobilization of MBP on Gelatin and Gelatin-Titanium Dioxide (TiO₂) modified platinium electrode. Cyclic voltammetric (CV) and Electrochemical Impedance Spectroscopic (EIS) methods were employed in determination of the electrode responses and applicability. Gelatin-MBP and gelatin-TiO₂-MBP electrodes were prepared by chemical immobilization of the substrates onto the platinium electrodes. The formal potentials of MBP confined on gelatin-MBP and gelatin-TiO₂-MBP surfaces are estimated to be 195 and 205 mV, respectively. Thus, a little more reversible electron transfer reaction occurs on the gelatin-TiO₂-MBP immunosensor surface. The peak separations of MBP (150 mV and 110 mV s(-1) at 100 mV s(-1)) and the asymmetric anodic and cathodic peak currents indicate that the electron transfer between Anti-MBP and gelatin-MBP/gelatin-TiO₂-MBP immunosensor is quasireversible. Control samples containing a nonspecific human immunoglobulin G (hIgG) antibody were also studied, and calibration curves were obtained by subtraction of the responses for specific and nonspecific antibody-based sensors. Gelatin-MBP and gelatin-TiO₂-MBP immunosensors have detection limit of 0.1528 ng ml(-1) and 0.1495 ng ml(-1) respectively. This immunosensor exhibits high sensitivity and low response times (58 s for gelatin-MBP and 46 s for gelatin-TiO₂-MBP immunosensor). The developed label-free impedimetric immunosensors also provide a simple and sensitive detection method for the specific determination of Anti-MBP in human cerebrospinal fluid (CSF) and serum samples.

Lower than expected maraviroc concentrations in cerebrospinal fluid exceed the wild-type CC chemokine receptor 5-tropic HIV-1 50% inhibitory concentration

To measure maraviroc total cerebrospinal fluid (CSF) concentrations and compare them with total and unbound plasma concentrations. Total maraviroc was measured by reverse-phase high-performance liquid chromatography with tandem mass spectrometry, whereas ultrafiltration was used for unbound maraviroc. Maraviroc was detected in all nine CSF/plasma pairs with a median CSF total concentration of 2.4 ng/ml. CSF concentrations exceeded the 50% inhibitory concentration of wild-type CC chemokine receptor 5-tropic HIV-1 in all specimens. CSF concentrations are lower than expected based on plasma concentrations and physicochemical characteristics. Unbound maraviroc plasma concentrations may be informative in estimating concentrations in CSF.

Total raltegravir concentrations in cerebrospinal fluid exceed the 50-percent inhibitory concentration for wild-type HIV-1

HIV-associated neurocognitive disorders continue to be common. Antiretrovirals that achieve higher concentrations in cerebrospinal fluid (CSF) are associated with better control of HIV and improved cognition. The objective of this study was to measure total raltegravir (RAL) concentrations in CSF and to compare them with matched concentrations in plasma and in vitro inhibitory concentrations. Eighteen subjects with HIV-1 infection were enrolled based on the use of RAL-containing regimens and the availability of CSF and matched plasma samples. RAL was measured in 21 CSF and plasma pairs by liquid chromatography-tandem mass spectrometry, and HIV RNA was detected by reverse transcription-PCR (RT-PCR). RAL concentrations were compared to the 50% inhibitory concentration (IC(50)) for wild-type HIV-1 (3.2 ng/ml). Volunteers were predominantly middle-aged white men with AIDS and without hepatitis C virus (HCV) coinfection. The median concurrent CD4(+) cell count was 276/μl, and 28% of CD4(+) cell counts were below 200/μl. HIV RNA was detectable in 38% of plasma specimens and 4% of CSF specimens. RAL was present in all CSF specimens, with a median total concentration of 14.5 ng/ml. The median concentration in plasma was 260.9 ng/ml, with a median CSF-to-plasma ratio of 0.058. Concentrations in CSF correlated with those in with plasma (r(2), 0.24; P, 0.02) but not with the postdose sampling time (P, >0.50). RAL concentrations in CSF exceeded the IC(50) for wild-type HIV in all specimens by a median of 4.5-fold. RAL is present in CSF and reaches sufficiently high concentrations to inhibit wild-type HIV in all individuals. As a component of effective antiretroviral regimens or as the main antiretroviral, RAL likely contributes to the control of HIV replication in the nervous system.

Protein expression profiles in pediatric multiple sclerosis: potential biomarkers

The diagnosis of pediatric multiple sclerosis (MS) is challenging due to its low frequency and the overlap with other acquired childhood demyelinating disorders of the central nervous system. To identify potential protein biomarkers which could facilitate the diagnosis, we used two-dimensional gel electrophoresis (2-DE) in combination with mass spectrometry to identify proteins associated with pediatric MS. Plasma samples from nine children with MS and nine healthy subjects, matched in aggregate by age and gender, were analyzed for differences in their patterns of protein expression. We found 12 proteins that were significantly up regulated in the pediatric MS group: alpha-1-acid-glycoprotein 1, alpha-1-B-glycoprotein, transthyretin, apoliprotein-C-III, serum amyloid P component, complement factor-I, clusterin, gelsolin, hemopexin, kininogen-1, hCG1993037-isoform, and vitamin D-binding protein. These results show that 2-DE in combination with mass spectrometry is a highly sensitive technique for the identification of blood-based biomarkers. This proteomic approach could lead to a new panel of diagnostic and prognostic markers in pediatric MS.

Cerebrospinal-fluid profile in neuroborreliosis and its diagnostic significance

Selected cerebrospinal-fluid (CSF) parameters (intrathecal synthesis of Borrelia-specific antibodies, oligoclonal IgG bands, CSF-to-serum quotient of albumin as a marker of blood-CSF barrier function and cytology) and typical CSF profile in neuroborreliosis were evaluated with the aim of elucidating possible clinical and laboratory similarities of neuroborreliosis (NB) and other neurological diseases (OND). From the cohort of 58 patients (38 diagnosed for NB, 20 with OND) NB patients had positive Borrelia-specific IgG antibodies in 97 % and positive Borrelia-specific IgM antibodies in 55 %; oligoclonal IgG bands were detected in 55%. The blood-CSF barrier was impaired in 89%, positive cytology was detected in 97% of the NB patients. Evaluation of specific intrathecal synthesis improves CSF diagnosis of NB, therefore, a combined CSF analysis has to be considered along with the clinical picture and medical history when formulating the diagnosis of NB.

Elevated haptoglobin level of cerebrospinal fluid in Guillain-Barré syndrome revealed by proteomics analysis

Guillain-Barré Syndrome (GBS) is a rare autoimmune inflammatory polyneuropathy with a high risk of respiratory failure and unclear pathogenesis. Currently, there are no valid biomarkers for diagnosis of GBS. We used 2-DE and MS to analyze the protein profiles of five pairs of cerebrospinal fluid (CSF) samples of the GBS patients and the patient controls. Three proteins (orosomucoid, haptoglobin and apolipoprotein A-IV) were up-regulated, and two proteins (prostaglandin D2 synthase and transthyretin) were down-regulated in the CSF of the GBS patients. The CSF haptoglobin level, quantified by enzyme-linked immunosorbent assay, was significantly higher in the GBS patients (12.44 ± 2.70 μg/mL) compared to the chronic inflammatory demyelinating polyradiculoneuropathy (2.82 ± 0.83 μg/mL), viral meningitis (3.57 ± 0.97 μg/mL) and control patients (1.44 ± 0.35 μg/mL, p<0.05). This study indicated that protein profile analysis using a combination of 2-DE and MS provides an effective strategy for elucidating the pathogenesis and identifying potential CSF biomarkers for GBS. The raised intrathecal synthesis of haptoglobin specifically only in GBS patients, but not in patients with other neurological diseases examined, provides evidence of central nervous system involvement in GBS, and may be used as a potential diagnostic marker for GBS.

Critical evaluation of the biological role of IgM in cerebrospinal fluid in inflammatory and other diseases of the nervous system

In a group of 10,156 patients with neurological diseases, the IgM level was assessed (using laser nephelometry) both in cerebrospinal fluid (CSF) and serum; concentration of other 17 protein fractions was also simultaneously determined: albumin, immunoglobulins, acute phase reactants, complement components, apolipoproteins, proteinase inhibitors and alpha1-microglobulin. Total protein, element counts and glucose level were also evaluated. In patients with normal CSF findings, only limited statistically significant correlations were demonstrated between IgM and other CSF protein fractions while, in the group of patients with pathological CSF findings, significant correlations were found between CSF(IgM) and other immunoglobulins, complement fractions and the rate of intrathecal synthesis of immunoglobulins. Correlations were also found between CSF(IgM) and CSF antithrombin-III and alpha1-microglobulin. Correlations between CSF(IgM) and CSF apolipoproteins support the theory of CNS tissue destruction whenever the concentration of CSF apolipoproteins is elevated. Our data substantially contribute to establishing the diagnosis in patients with neurological diseases; simultaneous measurement of a high number of CSF proteins is becoming inevitable for a reasonable assessment of the CSF Protein Status.