Isoelectric focusing of CSF proteins in neurological diseases

Abnormal microheterogeneity of transferrin in serum and cerebrospinal fluid in alcoholism

The serum and CSF proteins were analyzed by isoelectric focusing in 16 male alcoholics after alcohol intoxication and after 10--14 days of alcohol abstinence. An abnormally marked protein band with pI 5.7 was found in serum in 15 patients and in CSF in 12 at the first examination. On crossed immunoelectrofocusing it appeared as an increased, cathodal, microheterogeneous molecular form of transferrin. The abnormality was reversible and decreased or normalized in serum in all cases after abstinence. In 6 patients with clinical signs of cerebellar degeneration, an abnormal microheterogeneous pattern of CSF transferrin of partly different appearance to that in serum remained after abstinence. Disturbed liver synthesis of transferrin is a probable origin of the serum finding, which may be specifically related to alcohol abuse. Substitution or loss of acidic amino acids and/or decreased iron binding ability are possible structural explanations.

Clinical significance of abnormal heterogeneity of transferrin in relation to alcohol consumption

An abnormal microheterogeneous component of serum transferrin, with a higher isoelectric point than the normal main component, was studied by means of isoelectric focusing and direct immunofixation in 98 alcoholic patients, 22 patients with liver diseases and 100 controls. Its relation to acute and prolonged ethanol intake was studied in healthy volunteers. The abnormal transferrin component was found to be a sensitive indicator of prolonged, high alcohol ingestion, and was observed in 81% of patients with an admitted consumption of more than 60 g ethanol/day, and normalized after at least 10 days of abstinence. It occurred in 1% of the controls and in none of the cases with liver diseases without current alcohol abuse. There is evidence of a reduced sialic acid content in the abnormal transferrin. No similar change has been found in a number of other glycoproteins. This test may be a useful and sensitive tool for the detection of chronic alcohol consumption.

Isoelectric focusing in an immobilized pH gradient for the detection of intrathecal IgG in cerebrospinal fluid: sensitivity and specificity for the diagnosis of multiple sclerosis

Cerebrospinal fluid and serum from 192 patients was analysed for the presence of intrathecally synthesized oligoclonal IgG bands using isoelectric focusing in an immobilized pH gradient pH 7-10. The sensitivity of this method for the diagnosis of multiple sclerosis (MS) was 95% (21 of 22), or 75% if patients with suspected MS were included. The specificity for the diagnosis of MS was 98%, or 96% if the suspected MS patients were included. The very high specificity may be because the intrathecally synthesized oligoclonal IgG associated with MS is more alkaline than IgG from serum and is better detected in an immobilized alkaline pH gradient.

The separation and detection of alkaline oligoclonal IgG bands in cerebrospinal fluid using immobilised pH gradients

A method is described for the separation and detection of highly alkaline IgG bands in unconcentrated cerebrospinal fluid (CSF). These bands are frequently found in the cerebrospinal fluid of patients with inflammatory diseases of the central nervous system, particularly in the case of multiple sclerosis, and their detection is an important aid in clinical diagnosis. An isoelectric focusing technique using an immobilised pH gradient in polyacrylamide gel has been developed over the pH range 7-10, producing a linear and stable pH gradient with excellent resolution. After electrofocusing, the protein patterns were blotted onto polyvinylidene difluoride membranes and visualised using anti-human IgG followed by an enzyme-labelled second antibody. Blotting could be carried out by capillary diffusion for up to 16 h duration without any loss in resolution. Using this method, highly alkaline intrathecal IgG bands were found in the cerebrospinal fluid of all of the 14 multiple sclerosis patients. There were also 2 patients with alkaline IgG bands in their cerebrospinal fluid who were not diagnosed as multiple sclerosis. By contrast, no alkaline IgG bands with an isoelectric point (pI) greater than 8.6 were found in any of the serum samples studied (n = 50) from patients with various neurological disorders including multiple sclerosis.

The HAF enigma: origin and clinical consequences of the appearance of high alkaline fractions on isoelectric focusing patterns of cerebrospinal fluid

High alkaline fractions (HAF) are irregularly present on isoelectric focusing (IEF) patterns of cerebrospinal fluid (CSF). Therefore, this phenomenon was studied retrospectively in more detail. First, the appearance of HAF in time was recorded and attempts were made to discover a relationship to the biochemical parameters of CSF. No such relationship could be established, nor could any effect of age or sex of the patients or any correlation with ambient temperature or clinical diagnosis be shown. Finally, we have shown conclusively that the cause of this random appearance of HAF can be found in the collodion bags used to concentrate the CSF. This irregular feature of the collodion bags also produces a rise in the frequency of appearance of oligoclonal bands on IEF, probably by blocking the passage of proteins. We conclude that the CSF contains protein material, and that the passage of this through the collodion filters during CSF concentration depends on the regularity of composition of the filters used, occasioning the presence (or absence) of a HAF. Of even greater consequence is the observation that when HAFs do not pass a certain collodion filter, other protein-like material can also be retained, leading to the appearance of oligoclonal bands in IEF, and causing more frequent occurrence of IEF patterns containing oligoclonal bands in CSF. Also, a slight change in the spectrum of oligoclonal bands of CSF has been found when HAFs occur. This indicates that the collodion bags do not retain all protein material in the same way.

Cerebrospinal fluid protein analysis in diseases of the nervous system

Electrophoretic studies of human CSF proteins from patients with diseases of the NS are reviewed. Various 1-DE methods are of similar value in identifying the non-specific OBs, which are helpful in the diagnosis of MS and recurrent GBS. In early and subclinical MS, OBs are of prognostic value, with IEF gels having the greater resolution. Silver-stained 2-DE gels provide the equivalent information to the OBs on 1-DE gels, with even greater sensitivity, and yield additional disease-associated protein data. Two proteins have proven to have diagnostic value in CJD and other changes that are still being evaluated have been identified in Parkinson's disease, GBS, Alzheimer's disease, schizophrenia and Herpes simplex encephalitis. The vastly improved CSF protein information obtained with silver-stained 2-DE gels heralds both a change from the relatively limited applications with 1-DE methods and also the need to adopt this approach in the routine clinical laboratory.

Oligoclonal and polyclonal synthesis of IgG in the central nervous system: an isoelectric focusing study

The IgG pattern in isoelectric focusing (IEF) has been studied in 90 paired samples of cerebrospinal fluid (CSF) and sera obtained from patients in which intrathecal synthesis of IgG without barrier damage was detectable by Reiber's graph and formula (1980, J. Neurol. 224, 89). Thirty patients were affected by multiple sclerosis (MS), 30 by other inflammatory nervous diseases (OID), and 30 by noninflammatory nervous diseases (NID). At IEF two distinct pathological patterns of CSF IgG were detected: oligoclonal bands (OB), prevailing in the MS group (83% of cases), and a "polyclonal"--i.e., diffuse, uniform--increase of CSF IgG, prevailing in the NID (90%). The OID group was intermediate, 57% of cases with OB and 43% with polyclonal CSF IgG patterns. Overall, only 45 of 90 patients synthesizing IgG in the CNS had CSF OB. This suggests that the CNS immune response can imply either the synthesis of IgG of restricted heterogeneity (i.e., OB) or a polyclonal IgG synthesis, giving in IEF a serum-like pattern to the CSF.

Cerebrospinal fluid and neuropathological study in Devic's syndrome. Evidence of intrathecal immune activation

Cerebrospinal fluid (CSF) was studied in 2 cases of Devic's syndrome (DS). In one of these cases autopsy was carried out. The main CSF feature in DS is the association of blood-brain barrier damage and intrathecal IgG synthesis. These findings are in keeping with our neuropathological observation of diffuse central nervous system vasculitis and leptomeningitis. As a whole, our CSF and neuropathological findings in DS are consistently different from those in multiple sclerosis.

Electrophoresis and immunoblot of cerebrospinal fluid proteins in spasmodic torticollis

Protein patterns of cerebrospinal fluid (CSF) from patients with spasmodic torticollis (ST) were investigated to determine whether abnormalities previously reported could be detected and further identified. CSF was collected from 12 patients with ST and 6 normal controls. The CSF proteins were analyzed using sodium dodecyl sulfate (SDS) polyacrylamide gel electrophoresis and silver staining. In 11 of the 12 patients with ST, a CSF protein pattern was observed which differed from that in the controls. The identity of the abnormal proteins was ascertained by blotting and immunostaining with specific antisera to IgG and ceruloplasmin (Cp). CSF from 2 of 12 patients had distinct bands staining for IgG and 7 had abnormal immunostaining for Cp.

Detection of IgG oligoclonal bands in unconcentrated CSF by means of agarose isoelectric focusing, double immunofixation peroxidase staining and avidin-biotin amplification

To detect immunoglobulin G (IgG) oligoclonal bands in unconcentrated cerebrospinal fluid (CSF) we used a recently developed method combining agarose isoelectric focusing (IEF) and double immunofixation peroxidase staining with Avidin-Biotin amplification. We studied 65 CSF and serum paired specimens from normals, multiple sclerosis (MS), other neurological diseases (OND) and benign monoclonal gammopathies (BMG). We found that the oligoclonal IgG pattern can be demonstrated after IEF of 15 microliter of CSF specimens with an IgG concentration of 15 mg/L. In 98% of CSF from patients with clinically definite MS a sharp oligoclonal band pattern was detected. The reliability and the sensitivity of this powerful technique is compared to agarose IEF of concentrated CSF, followed by Coomassie Brilliant Blue staining. This method constitutes a real improvement in the detection of CSF IgG oligoclonal bands because it avoids CSF concentration and allows the detection of IgG bands only.

High electroendosmotic agarose electrophoresis and nitrocellulose immobilisation for the detection of oligoclonal bands in unconcentrated cerebrospinal fluid

A sensitive (1 microL of unconcentrated sample), specific (IgG Fc) and economical (10 p/test) method for the detection of oligoclonal bands in cerebrospinal fluid is presented. Using commonly available technology (agarose gel electrophoresis) and giving results within 6 h, the approach used here is a powerful tool in the investigation of immunoglobulin abnormalities in many biological fluids.

Detection and identification of virus-specific, oligoclonal IgG in unconcentrated cerebrospinal fluid by immunoblot technique

A technique is described which allows the detection of virus-specific oligoclonal IgG in unconcentrated cerebrospinal fluid (CSF) from patients with virus infections of the central nervous system. CSF is isoelectrically focused in agarose gels and immunoglobulins are blotted to nitrocellulose filters, passively loaded with either anti-human IgG or viral antigen. Transferred total IgG, as well as virus-specific IgG, is identified by the use of peroxidase-labelled anti-human IgG and 4-chloro-1-naphthol as a precipitating peroxidase substrate. Application of this assay in cases of SSPE, mumps meningitis and herpes simplex encephalitis demonstrates sensitivity and possible suitability of this technique for use in diagnosis of virus infections of the CNS.

Pattern-reversal electroretinograms and visual evoked cortical potentials in multiple sclerosis

Pattern-reversal and flash electroretinograms (ERG) and visual evoked cortical potentials (VECP) were recorded from 15 patients with definite multiple sclerosis (MS). All patients had prolonged VECP latency, indicating demyelination of one or both optic nerves. The pattern-reversal ERG amplitude was reduced below the level of normal variation (mean -2 SD) in 11 of the 22 eyes with prolonged VECP latency and in one of the eight eyes with normal VECP latency. The mean pattern-reversal ERG amplitude from eyes with prolonged VECP latencies was significantly lower than the mean amplitude from the normal controls. No abnormalities were observed in the flash ERGs. Degeneration of retinal ganglion cell axons has been demonstrated in MS patients. The amplitude reduction in the pattern-reversal ERG, observed in some 50% of the eyes with prolonged VECP latencies, is supposed to reflect retinal ganglion cell dysfunction or degeneration secondary to demyelination of the optic nerve.

Cerebrospinal fluid (CSF) findings in amyotrophic lateral sclerosis

The cerebrospinal fluid (CSF) was examined in 90 amyotrophic lateral sclerosis (ALS) patients and in 50 age-matched normal controls. Total protein concentration was significantly higher in ALS patients than in normal controls. CSF IgG and albumin, quantitatively determined by single radial immunodiffusion, were significantly increased in ALS. No difference in serum concentrations was observed between ALS patients and normal controls. On isoelectric focusing a clearcut "fingerprint" pattern was observed in 11 of 12 cases. These findings support the hypothesis that blood-brain barrier damage occurs in ALS. The finding of a higher mononuclear cell count in young ALS patients is briefly discussed in the light of the hypothesis that an exogenous agent might be of some relevance in pathogenesis. An alteration of at least one of the CSF parameters considered was found in 45.5% of ALS cases.

Neuroimmunology in multiple sclerosis

A review of latest immunological interpretations regarding the pathogenesis of Multiple the Sclerosis. Data on a new immunoenzymatic method for the identification of blood lymphocyte populations are presented together with preliminary results relating to an immunogenetic correlation between primary affective disorders and Multiple Sclerosis.

Assessment of cerebrospinal fluid immunoglobulin patterns after isoelectric focusing. Use of kappa and lambda light chain immunoperoxidase staining

Assessment of the presence of immunoglobulin (Ig) of restricted heterogeneity i.e. oligoclonal Ig in cerebrospinal fluid subjected to isoelectric focusing (IEF) may be difficult because of the tendency of the technique to subdivide even normal polyclonal IgG into bands and zones. Focused Ig stained by the immunoperoxidase technique for kappa and lambda light chains shows correspondence between the two patterns in the case of normal polyclonal Ig, but a marked discrepancy between kappa and lambda patterns in disorders associated with oligoclonal Ig, and kappa and lambda immunofixation makes assessment of agarose IEF separations of IgG more reliable.

Peripheral neuropathy in patients with benign monoclonal gammopathy--a pilot study

It is well known that peripheral neuropathy occurs in patients with myeloma or macroglobulinaemia, but its pathogenesis is still obscure. In recent years, neuropathy has also been reported in association with benign monoclonal or oligoclonal gammopathy. Modern histo-immunological methods have revealed evidence of antibody production to peripheral nerve tissue, probably the myelin sheath. The present study included 21 unselected, consecutive patients with benign monoclonal gammopathy observed in the Division of Haematology. Clinical and laboratory investigations included electrophysiological examination and analyses of the M components. Of the 21 patients 11 had noticed slight neuropathic symptoms in their extremities; in 5 both clinical and electrophysiological findings were compatible with neuropathy; 6 showed positive clinical signs of neuropathy; 4 had either positive electromyographic or electroneurographic findings. In summary, 15 of 21 patients had some signs of peripheral neuropathy. In spite of the screening design of the study, this strikingly high frequency is comparable with other recent reports. Haematological studies did not reveal any significant differences between the patient groups with positive or negative neurological findings. The findings indicate that even benign gammopathies may be associated with peripheral neuropathy.

Microdialysis of cerebrospinal fluid in polyacrylamide gels: a suitable procedure prior to electrophoretic analysis

Most electrophoresis methods for separation of CSF proteins are generally preceded by some procedure of concentration and desalting of the specimen. Generally ultrafiltration techniques are used. The risk of losses, which may be unequal for different CSF proteins during such procedures, is to be stressed. On the other hand, desalting prior to isoelectric focusing (IEF) will minimize the curvature of the protein bands, and in isotachophoresis (ITP) faster separation and increased capacity with repeated sample application are made possible. Since some years microdialysis of samples has been performed by the authors and found to be a valuable procedure both prior to IEF and ITP. With respect to microheterogeneity and recovery, tested by IEF, immunonephelometry and radioiodinated proteins no losses were observed. Ion exchange of acrylamide in a mixed resin, and recrystallization of bisacrylamide, were found necessary to avoid absorption from very dilute protein solutions as CSF. Gel structure and performance were very dependent on polymerization conditions (time, temperature, initiator and accelerator concentrations).

High-voltage isoelectric focusing in ultrathin gels and enzyme-amplified immunoassay: a new method for analysis of cerebrospinal fluid proteins

A procedure using high-voltage isoelectric focusing (IF) in ultrathin (02. mm) gels and enzyme-amplified immuno-sandwich assay was elaborated to get optimal IF separation conditions, to avoid CSF concentration, e.g. by ultrafiltration preceding IF with the risk of unequal protein losses, to minimize the amounts of CSF and expensive reagents needed, especially antibodies and to shorten the analysis time, including the selective detection of proteins. The high voltage (2000-3000 V/10 cm) and efficient cooling during IF were obtained using ECPS 3000/150 and FBE 3000 (Pharmacia, Sweden). Ampholytes (Pharmalytes) of different pI intervals were used. The CSF and (diluted) serum samples were microdialysed in polyacrylamide gel before IF to minimize band curvature and to obtain optimal resolution. The IF separation was performed in about 1 h. Owing to the rapid fixation of ultrathin gels after IF, full use could be made of the high-voltage resolving capacity. The thin gels also made histochemical techniques applicable. Different immunological identification assays have been tested. An enzyme-amplified (alkaline phosphatase) immuno-sandwich method was found to be very sensitive and selective, and has so far given the best results. Many proteins in the same sample, applied as a line on the gel before IF, could be detected by overlaying antibody-soaked membrane strips. Furthermore, one specific protein could be examined in many samples simultaneously by overlaying or immersion of diluted antibody solutions. A few microlitres of unconcentrated CSF and diluted serum were used for the analysis performed within 1 day. The findings for albumin, transferrin and IgG in CSF and sera from patients with different neurological diseases, especially including cases with "normal" CSF, barrier damage, degenerative and demyelinating disorders, have been compared with the corresponding protein-stained (Coomassie R-250) patterns where the CSF had been concentrated by a special vacuum evaporation technique before IF.

Rapid analysis of immunoglobulin isoelectric focusing patterns with cellulose nitrate sheets and immunoperoxidase staining

Immunoglobulins which have been focused to their isoelectric points in thin-layer polyacrylamide gels can be transferred by diffusion to the surface of cellulose nitrate sheets with retention of the original focusing patterns. IgG can be detected with peroxidase-linked antiserum. Unlike polyacrylamide gel, cellulose nitrate offers no permeability barrier, and so washing times are reduced from days to minutes. Thus small quantities (less than 1 microgram) of IgG may be visualized within 24 h of isoelectric focusing. In addition after immobilization on cellulose nitrate, immunoglobulin reactivity with antigens, including those of high molecular weight, may be analysed.

Oligoclonal IgG in multiple sclerosis and subacute sclerosing panencephalitis brains

IgG was obtained from multiple sclerosis (MS) and subacute sclerosing panencephalitis (SSPE) brain materials by elution at neutral and acid pH, and by freezing and thawing. Serum, cerebrospinal fluid (CSF), and brain eluates were compared by isoelectric focussing (IEF) with sensitive peroxidase-anti-IgG staining. In 3 MS cases, different plaques or regions of the same brain had IgG patterns with some common and some different bands. Pooled white matter eluates contained the summation of bands seen in individual plaques or regions. Comparison of serum, CSF, and neutral and acid brain eluate IgG patterns showed many common bands but also unique bands. In two SSPE cases, eluates from different regions of the same brain showed virtually identical IgG patterns. Comparisons of serum, CSF, and neutral and acid eluates of the same brain also showed a common pattern of bands. Similarities in IgG patterns of sera, CSF, and regional brain eluates, from single cases of SSPE, suggest a common response to the same antigen in all regions or compartments. Differences in IgG patterns of sera, CSF, pooled brain eluates, and plaques or regional eluates from single cases of MS, suggest: either that (a) all MS oligoclonal IgG is "nonsense' antibody in terms of disease pathogenesis, or (b) much of the MS oligoclonal IgG is "nonsense' antibody, present as part of a specific oligoclonal immune reaction.

Identification of the kappa and lambda light chains within the CSF immunoglobulin region in multiple sclerosis and subacute sclerosing panencephalitis by immunofixation after isoelectric focusing

The distribution of the kappa and lambda light chains within the cerebrospinal fluid (CSF) IgG oligoclonal bands of 15 multiple sclerosis (MS) and 3 subacute sclerosing panencephalitis (SSPE) patients has been studied by isoelectric focusing (IF) followed by direct immunofixation. The oligoclonal bands demonstrated by IF were both homogeneous and heterogeneous with regard to the light chain type; in the MS patients there was a prevalence of heterogeneous bands and of homogeneous bands of lambda type, while in SSPE a slight prevalence of kappa homogeneous bands was found. The kappa homogeneous bands were preferentially disposed in a more cathodal position in respect to lambda IgG bands; in some cases bands probably constituted only of free light chains of lambda type were found. Finally, in some cases, the oligoclonal IgG pattern was more distinct after immunofixation than after basal IF.

Effects of bromocriptine on CSF proteins and amines in patients with empty sella syndrome, acromegaly and prolactin producing pituitary adenomas

The effect of the dopamine agonist bromocriptine (5-40 mg/day) on cerebrospinal fluid proteins and amines was studied in 7 hyperprolactinemic patients, 4 with empty sella syndrome and 3 patients with pituitary adenoma. Small as well as high doses of bromocriptine depressed the endogenously formed dopamine, noradrenalin and adrenalin. Five patients initially exhibited changes consistent with slight to marked blood-cerebrospinal-fluid (CSF) barrier disturbances and 5 abnormal CSF-protein fractions. One CSF-protein fraction (isolelectric points (pI) approximately 5.3 pH-units) became more prominent during bromocriptine treatment. Analyses of his fraction indicated that it represented a transferrin component. It is stated that bromocriptine treatment besides affecting amine and trace metal metabolism also affects protein metabolism.

Demonstration of oligoclonal immunoglobulin G in Guillain-Barré syndrome and lymphocytic meningoradiculitis by isoelectric focusing

Isoelectric focusing (IEF) of serum and CSF revealed oligoclonal IgG in 13 out of 16 patients with the Guillain-Barré syndrome (GBS), in 10 of them in serum only and in 3 in serum and CSF. Seventeen out of 19 patients with lymphocytic meningoradiculitis (LMR) showed oligoclonal IgG, 12 of them in CSF only. These findings, together with additional results, mean that in GBS oligoclonal IgG is synthesized mainly outside the CNS and in LMR within the CNS. Follow-up studies revealed changes in the oligoclonal IgG during the course of GBS and LMR. After treatment by plasma exchange the disappearance of oligoclonal IgG bands was followed by an improvement of GBS symptoms. The oligoclonal IgG bands returned in correlation with worsening of the disease. We were not able to elucidate the antibody character of oligoclonal IgG in GBS or LMR. No antibodies against the myelin basic protein (fragment 89-169) were detectable in the sera and CSF in any of the patients tested.

Cerebrospinal fluid investigations in multi-infarct dementia and senile dementia

Thirty-eight demented patients were clinically investigated and classified into a multi-infarct dementia (MID) and senile dementia (SD) group. Total protein, albumin, immunoglobulin G, agar gel electrophoretic protein and iso-electric focusing pattern were determined in CSF and serum as well as the lactate dehydrogenase, LD-iso-enzyme pattern and uric acid. No significant differences were found regarding total protein, albumin and immunoglobulin G. The agar gel electrophoresis showed a tau-globulin increase in 18% of the SD-group against 6% of the MID group. The patterns were, however, plasma-like in 56% of the MID group against 23% of the SD group. The iso-electric focusing pattern showed an abnormal band in some SD-patients which was not found in the MID group. The uric acid and LD-enzyme concentration was equal in both CSF and serum. An index [Formula: see text] was calculated to give an approximate correction for the influence of different permeability of the blood-brain and CSF barrier. A significantly higher LD-index was found in the SD-group, suggesting a continuous cell degeneration.

Cerebrospinal fluid IgG changes in subacute sclerosing panencephalitis in the various stages of the disease and during isoprinosine therapy

The cerebrospinal fluid (CSF) levels of IgG and the separation of the CSF and serum proteins by isoelectric focusing (IEF) were studied in 5 patients with subacute sclerosing panencephalitis (SSPE). Oligoclonal IgG fractions were found in the CSF of all the patients. The CSF IgG, IgG-Index and IgG SYN values were higher in the patients observed in the earlier than in those seen in the later stages of the disease. 1 of the 3 patients treated with isoprinosine presented a partial clinical remission accompanied by an increase in the parameters of intrathecal IgG synthesis.

Gel isoelectric focusing and IgG index for demonstration of intrathecal IgG synthesis in neurological disorders

Cerebrospinal fluid (CSF) and serum were obtained from 37 patients with multiple sclerosis and from 112 patients with various other neurological diseases, and the concentrations of IgG and albumin were quantitated immunochemically. Simultaneously, isoelectric focusing (IF) was carried out for the detection of CSF-specific oligoclonal bands in the alkaline region. CSF-specific components were found in 51 patients by IF, the estimated number of which correlated significantly (Rs = 0.733, p less than 0.0001) with the value of the IgG index. In addition, six patients without CSF-specific abnormalities on IF had an increased IgG index (greater than 0.70). In two of them this increase is, in all probability, false-positive; three others showed fully identical IF bands in both CSF and serum. On the other hand, 13 of the same 51 patients showed a normal IgG index (less than 0.70) although CSF-specific components were detectable on IF. These results confirm the superiority of IF over the immunochemical quantitation of albumin and total IgG for the evaluation of immune reactivity in the central nervous system.

Analysis of a predominant immunoglobulin population in the cerebrospinal fluid of a multiple sclerosis patient by means of an anti-idiotypic hybridoma antibody

We have produced hybridoma antibodies directed against immunoglobulins present in the cerebrospinal fluid of a patient with multiple sclerosis (MS). One hybridoma antibody recognized an idiotypic determinant of an immunoglobulin population [an idiotype (Id)] which constituted approximately 1% of the immunoglobulin present in the cerebrospinal fluid. The Id focused in the pH range 8.0-8.4. It was present at roughly 10- to 15-fold higher relative (compared to total immunoglobulin) concentration in cerebrospinal fluid than in serum of the homologous MS patient. The Id could not be detected in three cerebrospinal fluid samples and 28 serum samples of heterologous MS patients or in the serum of 43 optic neuritis patients. The Id persisted in the homologous MS patient at increased concentration over the entire (6 years) observation period. The Id could be shown to react with a Theiler murine encephalomyelitis virus strain WW which was isolated from mice after inoculation with periplaque white matter from brain in a histologically confirmed case of MS.

Intrathecal IgG synthesis in multiple sclerosis: comparison between isoelectric focusing and quantitative estimation of cerebrospinal fluid IgG

Isoelectric focusing of CSF and serum IgG followed by crossed immuno isoelectric focusing and direct immunofixation as well as quantitative assay of IgG and albumin were performed in 64 clinically definite multiple sclerosis patients. Intrathecal IgG synthesis was calculated according to the CSF IgG index and de novo CNS IgGsyn. Isoelectric focusing showed abnormal IgG fractions i CSF indicating increased intrathecal synthesis of oligoclonal IgG in 99% of patients. Only 62% and 70% of multiple sclerosis patients showed values of CSF IgG indices and de novo CNS IgGsyn higher than in controls. Increased intrathecal IgG synthesis was indicated more frequently by de novo CNS IgGsyn in patients with a normal CSF IgG index than by the CSF IgG index in patients with normal de novo CNS IgGsyn. All patients with blood CSF barrier damage had increased de novo CNS IgGsyn, but only 40% had an increased CSF IgG index. Isoelectric focusing seemed to be a more sensitive method to detect an increased intrathecal oligoclonal IgG synthesis than quantitative methods. Identification of abnormal IgG fractions can be performed easily and with more reproducible results by direct immunofixation than by crossed immuno isoelectric focusing. The formula for de novo CNS IgGsyn seemed more sensitive and less influenced by blood-CSF barrier damage than the CSF IgG index to detect increased intrathecal IgG synthesis in multiple sclerosis patients. No correlation was found between the CSF IgG pattern or amounts and age, duration, clinical course or therapy of the disease.

Comparison of agar gel electrophoresis and isoelectric focusing in multiple sclerosis and subacute sclerosing panencephalitis

Isoelectric focusing (IEF) and agar gel electrophoresis (AGE) were used to examine cerebrospinal fluid (CSF) and sera from patients with multiple sclerosis (MS) and subacute sclerosing panencephalitis (SSPE). All 15 SSPE samples and 29 of the 33 MS CSF samples showed oligoclonal IgG bands by AGE and IEF. Serum bands were more frequent in SSPE than in MS and were more commonly detected by IEF than by AGE. In MS CSF the number of bands on IEF correlated with: (1) disease duration, (2) CSF IgG, (3) CSF IgG/albumin ratio, and (4) central nervous system IgG synthesis. Serial studies revealed increases in IEF band number in 4 of 10 MS and 3 of 5 SSPE CSF specimens; fluctuations in band intensity were also noted. Densitometric scans of CSF IEF gels showed high, sharply angled IgG band peaks in SSPE; the CSF band peaks in MS were flatter and had higher background IgG. The SSPE pattern could be made to resemble the MS pattern through addition of normal polyclonal IgG to SSPE CSF. These findings suggest that in addition to oligoclonal IgG, polyclonal IgG is synthesized locally within the central nervous system in MS.

Immunoperoxidase staining of cerebrospinal fluid IgG in isoelectric focusing gels: a sensitive new technique

An isoelectric focusing (IEF) technique using direct peroxidase or peroxidase-antiperoxidase (PAP) overlay staining for detection of cerebrospinal fluid (CSF) oligoclonal IgG is described. The method involves chemical fixation of all proteins in the gel followed by application of peroxidase coupled antiserum as a specific stain. The direct peroxidase system is 4 times and the PAP system 8 times as sensitive as Coomassie blue staining after standard IEF or Coomassie blue staining of immunofixed gels. As little as 0.5 microgram (direct peroxidase) or 0.3 microgram (PAP) of IgG can be detected. Direct peroxidase staining of IgG in IEF gels can be used to examine unconcentrated CSF, with banding patterns similar to those obtained by Coomassie blue staining after standard IEF of concentrated CSF.

Abnormal CSF immunoglobulin components detected by isoelectric focusing

The results from thin-layer isoelectric focusing of 4000 paired CSF and serum samples were examined for the occurrence of abnormal CSF immunoglobulin components. Such changes, not referable to serum protein abnormalities, were detected in 630 samples from 465 patients. All but 3 of these subjects had symptoms and signs of an affection of the nervous system, predominantly MS and encephalitic or myelitic/radiculitic disorders of known or presumed infectious etiology. The abnormal, microheterogeneous immunoglobulin components were mostly focused in the pI range approximately 7.5--9 with generally a shift towards pI-values > 8 pH units; a distribution differing from that of M components in plasma cell dyscrasias.

The cerebrospinal fluid tau-transferrin. Isoelectric focusing study on 674 neurological patients

The frequency of the two tau-fractions in isoelectric focusing examination of cerebrospinal fluid proteins has been studied in 674 neurological patients. The double tau-fraction was found in 151 patients (22.4%); this finding was not characteristically associated with any particular disease, but its frequency was high in hereditary diseases (13 cases out of 30; 43.3%), mainly Charcot-Marie-Tooth's disease.

Isoelectric focusing of IgG eluted from multiple sclerosis and subacute sclerosing panencephalitis brains

Elevated IgG distributed in oligoclonal bands is characteristically observed in the cerebrospinal fluid (CSF) of patients with multiple sclerosis (MS) or subacute sclerosing panencephalitis (SSPE). Similarly, IgG in bands has been detected in neutral saline (NS) and acid eluates of brain material from these two diseases. We have now used isoelectric focusing (IEF) to compare IgG eluted from control brain, three plaques and a white matter pool of an MS brain, and three regions of an SSPE brain. A direct peroxidase-conjugated anti-human IgG staining technique was used to stain IgG exclusively and to visualize the minute amounts of IgG obtained from individual MS plaques. Eluates from individual MS plaques have distinct IgG patterns; in contrast, those from separate SSPE brain areas have essentially identical IgG patterns. The identical IgG patterns in three areas of SSPE brain suggest a common response to the same antigen. The different IgG patterns among MS plaques suggest: (1) variable response to the same 'MS antigen' in each plaque, (2) response to different MS antigens in different plaques, (3) synthesis of 'nonsense' antibodies irrelevant to the pathogenesis of MS in each plaque, or (4) some combination of the above.

Isoelectric focusing and quantitative estimation of cerebrospinal fluid and serum IgG in idiopathic polyneuropathy

Isoelectric focusing and quantitative estimation of serum and CSF IgG were performed in 85 patients with idiopathic polyneuropathy (IP), subdivided according to the clinical course (acute, subacute, recurrent, chronic). Acute IP very frequently had an increase of oligoclonal and/or polyclonal serum IgG during the progressive phase and blood-CSF barrier damage accompanied by polyclonal IgG intrathecal synthesis during the stationary phase. Polyclonal IgG intrathecal synthesis was also present in several not acute IP and seemed to forecast unfavorable course. Oligoclonal IgG synthesis occurs very rarely within CSF but is a frequent finding in serum of patients with IP. Abnormalities of the IgG serum pattern are neither specific for any clinical course of IP nor of prognostic value. The possible significance of such findings is discussed.

Isoelectric focusing of cerebrospinal fluid proteins in ischemic cerebrovascular disease

The cerebrospinal fluid (CSF) protein patterns, in ischemic cerebrovascular disease (ICD), of varying extension were studied by isoelectric focusing (IEF) in 100 patients at different intervals after the onset of symptoms. The diagnoses were based on conventional clinical examinations and CSF spectrophotometry in all cases. Computed tomography was performed on 52 cases. One or more CSF protein aberrations were noted in 94 patients. Some of these findings were most common with small lesions including TIA. Other aberrations were most frequent with the more extensive infarctions. A regional increase in the gammaglobulin range was found in six cases. The findings were most frequent in the first days after the stroke except for barrier damage which reached a maximum during the second week. The IEF findings of CSF seem to be of diagnostic value. Taken together with the clinical signs and CT findings, they could conceivably give prognostic information.

Separation of cerebrospinal fluid specific proteins -- a methodological study. Part I

A method for preparative separation of cerebrospinal fluid specific proteins by affinity chromatography and isoelectric focusing is described. It has been tested on CSF from a group of human patients suffering from TIA. The advantage of the method is the production of a protein pattern easy to survey by eye. The sensitivity and reproducibility are adequate, as tested by model experiments described.

Intrathecal IgG synthesis in multiple sclerosis and other neurological diseases: a comparative evaluation by IgG-index and isoelectric focusing

Intrathecal IgG synthesis has been investigated by determining the IgG index and by isoelectric focusing in 30 cases of definite multiple sclerosis, in 15 cases of probable multiple sclerosis and in 128 patients affected by other neurological diseases. The blood-brain barrier function was evaluated at the same time by serum albumin/CSF albumin quotient and isoelectric focusing. The IgG index was found elevated in 73.3% of definite multiple sclerosis patients, while oligoclonal IgG bands occurred in 90%. In the other neurological diseases the IgG index was abnormally increased in 35.1% but IgG bands were present only in cerebrospinal fluid (CSF) in 1.5% and both in the CSF and serum in 7% of patients. The high capacity of isoelectric focusing to detect IgG oligoclonal bands in the CSF is pointed out as an extremely useful diagnostic tool in multiple sclerosis.

Isotachophoresis of CSF proteins in gel tubes especially gammaglobulins. An analytical and preparative technique for high-separation of CSF proteins

An isotachophoretic method using polyacrylamide gel (PAG-ITP) in a simple disc electrophoretic equipment with plastic tubes containing the gels, was elaborated and especially designed for studying the gammaglobulins in CSF and serum from control subjects and patients with neurological disorders, especially known or probable MS. The device and the ITP system used, including leading and terminating electrolytes and spacer substances, dividing the gammaglobulins in a reproducible way, are described. No cooling of the gel tubes was needed. The sample volumes varied between 5--500 microliters, and the separation time was 1.5--3.0 h. CSF from patients with verified or probable MS revealed characteristic, increased low-mobility gammaglobulin fractions. Using other ITP systems, such as other spacer compositions, the anodic proteins can also be studied in more detail. PAG-ITP in gel tubes is a simple and inexpensive technique which can be used for both analytical and preparative procedures for biological material such as CSF, serum and extractions from nervous tissues.

Isoelectric focusing and crossed immunoelectrofocusing of CSF immunoglobulins in MS

The 3 main Ig classes and the presence of free light chains were studied by isoelectric focusing and crossed immunoelectrofocusing in 100 CSF samples from patients with clinically definitie or probable MS. Minute quantities of IgM and free light-chain (mostly lambda) components were found in 2 out of 11 and 5 out of 14 samples respectively. IgG and IgA were detected in all samples examined for these proteins and were found in the pI-ranges of 5.3-9.8 and 4.6-6.4 pH-units respectively. The gammaglobulin abnormalities found on isoelectric focusing were identified as microheterogeneous, oligoclonal IgG with predominantly kappa light-chain determinants. The IgG immunoprecipitates differed from those of normal subjects and the major abnormal components most frequently exhibited pI-values greater than 8 pH-units. The IgA immunoprecipitates had 2-4 main components with some tendency to discontinuous subfractionation. This Ig class, however, did not exhibit the marked tendency to oligoclonal distribution found for IgG.

Direct immunofixation after isoelectric focusing. An improved method for identification of cerebrospinal fluid and serum proteins

An improved method for identification of CSF and serum proteins is described, using analytical isoelectric focusing followed by direct immunofixation in polyacrylamide gel. This method offers high sensitivity together with retained resolution after isoelectric focusing and is technically easy to perform. The gamma-trace protein, normal transferrin, haptoglobin and alpha 2-macroglobulin and two genetic alterations of transferrin were analyzed. The qualitative differences, previously observed on crossed immunoelectrofocusing, between transferrin and alpha 2-macroglobulin in the CSF and serum were confirmed by immunofixation. Protein components, differing in isoelectric pH by at least 0.03 pH unit and 0.5 mm apart were readily identified by this technique.

Isoelectric focusing of CSF proteins in known or probable infectious neurological diseases and the Guillain-Barré syndrome

The CSF and serum proteins of 120 patients with known or probable infectious neurological diseases or the Guillain-Barré syndrome were examined with thin-layer IEF. All but two of these patients exhibited one or combinations of different CSF-protein aberrations in the acidic and alkaline range. Aberrant non-Ig fractions (including transferrin, the tau-fraction and gamma-trace protein) were found in frequencies varying between 4 and 48%. CSF Ig components of restricted heterogeneity, i.e. oligoclonal bands and/or regional increases of gamma-globulins, were more frequent in patients with (meningo-)encephalitic or (meningo-)-myelitis/radiculitic disorders (respectively 69 and 48%) than in subjects with meningitis or Guillain-Barré syndrome (17%). The occurrence of such Ig abnormalities was higher in subacute or chronic than in acute disease and in subjects examined greater than 4 weeks after the onset rather than earlier. Ig-band spectra with marked anodal extension were found predominantly in (meningo-)encephalitic disorders with infratentorial symptoms. Age and sex were not found to influence the occurrence of abnormal Ig fractions. Such components could be detected in spite of pronounced blood-CSF barrier defects.

Characterisation of the mobility on isoelectric focusing of individual proteins in CSF and serum by immunofixation

The mobility of 17 different proteins in CSF and serum on isoelectric focusing was investigated by subsequent immunofixation using monospecific antisera. Individual proteins yielded identical, often complex band patterns in normal CSF and serum, except transferrin which gave one to two additional bands between pH 5.8-6.4, and the low molecular wieght beta-trace protein and gamma-trace protein, which gave three bands at pH 7.4, 8.0, and 8.4, and a single band at pH 9.5, respectively, on investigation of CSF but not serum. Polyclonal IgC migrated as multiple bands between pH 4.7-8.6. Oligoclonal IgG in CSF in multiple sclerosis and neurosyphilis migrated between pH 8.6-9.5 and was easily discriminated from other proteins.

CSF protein examinations with thin-layer isoelectric focusing in multiple sclerosis

Thin-layer IEF, due to its extremely high resolving capacity, has been found to be quite valuable for CSF protein examinations, one important advantage of the technique being its excellent capacity for separation of immunoglobulins. The CSF and serum proteins of 230 patients with clinically verified or probable MS and 20 subjects with optic neuritis were examined with thin-layer IEF and the findings were compared with clinical data and results of other CSF examinations. All but 3 of the MS patients and about two thirds of the subjects with optic neuritis inhibited one or combinations of different CSF protein aberrations in the acidic and alkaline range. Oligoclonal bands and/or regional increases of Ig fractions, changes compatible with intrathecal Ig synthesis, were detected in respectively 95 and 80% of patients with clinically verified and probable MS and 30% of subjects with optic neuritis. Other aberrant CSF protein fractions (including transferrin, the taufraction and gamma-trace protein) were found in about half of the cases; some of these fractions had the highest occurrence in patients with the most extensive Ig abnormalities. The diverse CSF protein aberrations seemed to be influenced by the duration and course of the disorder as well as the probable sites of lesions; further factors might be the release of decomposition products from destroyed tissues, the genetically determined reactivity of the individual and the presence of possible agents.