Comparison between agarose gel electrophoresis and isoelectric focusing of CSF for demonstration of oligoclonal immunoglobulin bands in neurological disorders

Proteomics of Multiple Sclerosis: Inherent Issues in Defining the Pathoetiology and Identifying (Early) Biomarkers

Multiple Sclerosis (MS) is a demyelinating disease of the human central nervous system having an unconfirmed pathoetiology. Although animal models are used to mimic the pathology and clinical symptoms, no single model successfully replicates the full complexity of MS from its initial clinical identification through disease progression. Most importantly, a lack of preclinical biomarkers is hampering the earliest possible diagnosis and treatment. Notably, the development of rationally targeted therapeutics enabling pre-emptive treatment to halt the disease is also delayed without such biomarkers. Using literature mining and bioinformatic analyses, this review assessed the available proteomic studies of MS patients and animal models to discern (1) whether the models effectively mimic MS; and (2) whether reasonable biomarker candidates have been identified. The implication and necessity of assessing proteoforms and the critical importance of this to identifying rational biomarkers are discussed. Moreover, the challenges of using different proteomic analytical approaches and biological samples are also addressed.

Qualitative assessment of intrathecal IgG synthesis by isoelectric focusing and immunodetection: interlaboratory reproducibility and interobserver agreement

Detection of intrathecal IgG synthesis is important in patients with suspected multiple sclerosis (MS). The recommended method for the detection of intrathecal synthesis of IgG is isoelectric focusing and immunodetection of oligoclonal bands. Recently "The Committee for European Concerted Action for Multiple Sclerosis" has recommended that the results of isoelectric focusing for the detection of intrathecal synthesis of oligoclonal bands should not only be stated as positive or negative for intrathecal synthesis; instead, the laboratory should provide a detailed description of the IgG pattern in both cerebrospinal fluid (CSF) and serum together with a conclusion concerning the presence of intrathecal synthesis. We studied the interlaboratory reproducibility and interobserver agreement of isoelectric focusing, and the recommended classification system for the assessment of intrathecal IgG synthesis, in two separate patient groups employing kappa statistics. We found a high degree of interlaboratory reproducibility (133 patients; kappa = 0.95 +/- 0.05) and interobserver agreement (356 patients; kappa = 0.97 +/- 0.04) when the presence or absence of intrathecal IgG synthesis was assessed. The agreement was less pronounced, although still fully satisfactory, when the results were classified according to the detailed system by two laboratories (133 patients; kappa = 0.86 +/- 0.08) and two observers (356 patients; kappa = 0.88 +/- 0.08). Two specific problems in the interpretation of isoelectric focusing patterns were identified: one related to the discrimination of a pattern with several closely spaced bands which may represent a monoclonal protein; the other related to determining whether systemic band synthesis was present. We conclude that isoelectric focusing and immunodetection is a very reproducible technique for the detection of intrathecal IgG synthesis. Well defined criteria and extensive standardization may, however, be necessary when more elaborate classification systems are employed.

CSF oligoclonal bands, MRI, and the diagnosis of multiple sclerosis

In this retrospective study, the results from investigations (MRI, evoked potentials, alkaline oligoclonal bands [OBs] in CSF) in 94 patients with clinical suspicion of demyelinative disease were evaluated to assess their impact on diagnosis. Forty-three patients were diagnosed as having definite MS, 10 probable MS, and 9 possible MS. MRI findings strongly suggestive of MS were evident in 52/62 (84%) patients, while 47/62 (76%) patients demonstrated OBs in their CSF. In 63% of patients both abnormalities were present. Patients with no OBs in their CSF were on the average older, were more often male, had experienced their first symptoms at a later age, and suffered more often from the chronic-progressive form of the disease than those with a positive CSF finding.

Cerebrospinal fluid proteins in patients with leucoaraiosis: possible abnormalities in blood-brain barrier function

Some CSF protein abnormalities have been proposed as a possible marker for vascular dementia. We studied the CSF protein levels and albumin ratio in 21 patients (mean age 64.04 +/- 7.5) with progressive bilateral motor impairment, and a CT picture of leucoaraiosis. Seven of these patients also presented with dementia. Twenty-seven Alzheimer's disease patients (mean age 59.59 +/- 5.30) without leucoaraiosis were taken as controls. We also evaluated the correlations of the albumin ratio values with the diagnosis of dementia, the severity of cognitive impairment, the degree of cerebral atrophy and presence of infarcts on CT, and the abnormalities in CSF circulation, found on isotopic cisternography, in the leucoaraiosis group. After controlling for age and sex, the patients with leucoaraiosis showed greater CSF albumin levels (0.27 g/l +/- 0.11 vs. 0.21 g/l +/- 0.06; covariance analysis P = 0.066), CSF IgG values (4.68 mg/100 ml +/- 1.45 vs. 2.85 mg/100 ml +/- 1.03; covariance analysis P < 0.001), and a higher albumin ratio (0.0078 +/- 0.0027 vs. 0.0058 +/- 0.0019; covariance analysis P = 0.013) than those with Alzheimer's disease. The variations of these parameters were not apparently related to the presence of dementia in the leucoaraiosis group. A significantly higher albumin ratio was observed in patients with a slowed CSF circulation compared to those with normal CSF circulation (0.0086 +/- 0.0028 vs. 0.0059 +/- 0.0019; covariance analysis P = 0.05). We conclude that, independently from the presence of dementia, patients with leucoaraiosis have CSF abnormalities consistent with functional blood-brain barrier alterations.

Distribution of cerebrospinal fluid oligoclonal IgM bands in neurological diseases: a comparison between agarose electrophoresis and isoelectric focusing

Isoelectric focusing (IEF) and agarose gel electrophoresis were used to detect oligoclonal IgM bands in cerebrospinal fluid and serum samples from 850 patients with diverse neurological diseases. Oligoclonal IgM bands in cerebrospinal fluid were mainly detected in patients with infectious and inflammatory disorders of the nervous system. Both IEF and agarose electrophoresis revealed similar frequencies of oligoclonal IgM bands. Bands detected by IEF were mainly seen in the anodal range. Despite higher resolving capacity, IEF was less specific than agarose gel electrophoresis. It is concluded that oligoclonal IgM bands have important diagnostic significance and that agarose gel electrophoresis is more suitable for their detection in routine clinical work and use in differential diagnosis.

Detection of oligoclonal IgG bands in cerebrospinal fluid by immunofixation after isoelectric focusing on polyacrylamide gels with the PhastSystem

This paper describes the detection of oligoclonal bands of IgG immunoglobulins in cerebrospinal fluids (CSF) using isoelectric focusing (IEF) and immunofixation with the PhastSystem equipment. The proteins were separated by IEF on polyacrylamide gels, pH 3-9. The IgG immunoglobulins were then fixed by overlaying the gel with antihuman IgG antiserum. Fixed immunoglobulins were detected with silver staining in the PhastSystem Development Unit. One microliter of serum or CSF containing 15 mg/L of IgG was found to be optimal. The procedure had good reproducibility both with regard to IEF and silver staining of the fixed immunoglobulins. The manpower need was reduced, and the procedure has been found to be useful in the clinical laboratory.

Laboratory investigation of cerebrospinal fluid proteins

Analysis of CSF proteins is useful in the diagnosis and management of neurological diseases in the following situations: 1. In inflammatory conditions when there is breakdown of blood-CSF barrier integrity. Meningitis is a medical emergency, with CSF total protein measurement being only a screening test. 2. In the detection of immune responses within the CNS. This is by far the most important application in a routine clinical setting, as it is now a firmly established criterion in the diagnosis of multiple sclerosis. Oligoclonal bands restricted to the CSF are the only reliable indicators of intrathecal immunoglobulin G synthesis and are practically always associated with inflammatory disease of the CNS. The method fo choice for detecting oligoclonal bands is isoelectric focusing with immunofixation. Quantitative measurement of IgG in the CSF is of no value in diagnostic pathology. 3. In destructive brain diseases when brain-specific proteins are released into the CSF, measurement of these proteins can give prognostic information.

Immunoblotting techniques with picogram sensitivity in cerebrospinal fluid protein detection

Agarose isoelectric focusing followed by blotting with nitrocellulose, nylon or polyvinylidene difluoride membranes, and immunochemical detection of cerebrospinal fluid IgG with various combinations of antisera, was evaluated. Polyvinylidene difluoride proved to be an easy-to-handle and reliable membrane for protein blotting. Among immunochemical visualization reactions, the most sensitive employed biotinylated goat anti-human IgG followed by streptavidin colloidal gold conjugate and silver enhancement in 20% w/v urea, allowing a sensitivity of less then 1 picogram IgG/band.

Immobilized pH gradient isoelectric focusing of cerebrospinal fluid proteins

Isoelectric focusing in immobilized pH gradients, supplemented with 0.5% w/v carrier ampholytes was applied for studies of native proteins, especially immunoglobulin G, in cerebrospinal fluid and serum. All 72 paired samples were run on pH 4-10 gels; 25 of them were also examined in pH 7-10 gels. Silver staining and nitrocellulose blotting with amplified immunoperoxidase detection of immunoglobulin G were used for protein visualization. Intrathecally produced immunoglobulin G was resolved into sharply focused, straight and easily identifiable fractions. The pH gradients were stable and the inter-gel reproducibilities of individual immunoglobulin G patterns were good.

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.

Detecting immunoglobulin abnormalities in the cerebrospinal fluid (CSF): which methods are best for clinical purposes?

Several techniques are now available for the quantitative and qualitative examination of CSF proteins modified during the course of neurological disease. The CSF and serum of 42 patients suffering from various neurological diseases and of 7 controls were examined using quantitative methods--single radial immunodiffusion, nephelometric analysis--and qualitative methods--isoelectric focusing on polyacrylamide gel and on agarose gel, isoelectric focusing of unconcentrated CSF followed by transfer to cellulose nitrate membranes and immunoperoxidase staining and double antibody peroxidase labeling and avidin-biotin amplification. In the present study the results and the advantages of different methods are described and compared.

Demonstration in children of oligoclonal IgG bands in unconcentrated CSF using agarose isoelectric focusing and immunolabeling

Agarose isoelectric focusing, followed by protein transfer to cellulose nitrate membrane and double-antibody avidin-biotin peroxidase staining (avidin-biotin agarose isoelectric focusing), was used to demonstrate oligoclonal IgG bands in unconcentrated cerebrospinal fluid (CSF) and serum; 161 consecutive pediatric patients, ages 6 months to 16 years with a variety of mainly neurologic disorders, were studied. The procedure was standardized for agarose isoelectric focusing (AIF) using 5 microliter specimens containing 125 ng of IgG. Oligoclonal bands were found in the CSF of 12% of the patients; bands were found simultaneously in the CSF and serum of 10% of the patients, mostly those with nervous system infections, but also those with central nervous system tumors, seizures, or migraine. In about 50% of positive cases, oligoclonal bands constituted the only CSF abnormality, reflecting an abnormal humoral immune response within the CSF-central nervous system compartment. Avidin-biotin AIF can be recommended as an integrated part of routine CSF examinations in children.

Multiple sclerosis: neuroimmunologic puzzle

Multiple sclerosis (MS), a chronic disease with a relapsing and remitting course, is the most common neuroimmunologic condition in the United States. The hallmarks of the disease are focal demyelination and inflammation within the central nervous system (CNS). Because histopathologic changes can be identified only at autopsy, attention has been directed at formulating standardized clinical and laboratory procedures to aid in MS diagnosis. Currently, there are no MS-specific clinical or laboratory tests, but detection of abnormality in cerebrospinal fluid (CSF) IgG is important in supporting clinical evidence of disease. A number of other immunologic abnormalities have been recognized in MS, including the presence of T- and B-lymphocytes within the CNS and alterations in circulating suppressor T-lymphocytes. These findings have been interpreted as indicating disturbed immunoregulation associated with a chronic autoimmune response within the CNS. Evidence implicates viral infection in the pathogenesis of MS but the cause of the disease remains unknown.

Immunoglobulins in serum and cerebrospinal fluid from patients with acute Guillain-Barré syndrome

IgG, IgA, IgM and IgE were quantified in serum and IgG and total protein were quantified in cerebrospinal fluid (CSF) from 80 patients with acute Guillain-Barré syndrome. The serum concentrations of IgM and IgA were significantly increased in approximately 25% of the patients, whereas the concentrations of IgG and IgE were normal. Increased CSF concentrations of IgG were found in more than 90% of the patients and correlated with increased CSF total protein concentrations. The CSF IgG/total protein ratio, CSF IgG index and Tourtellotte's formula were used to determine intra-thecal IgG synthesis in 30 of the patients. In eight of the patients the results of the CSF IgG index and Tourtellotte's formula were significantly increased, while in the remaining seven patients increased values were obtained using only one of these formulae. The CSF IgG/total protein ratio was normal in all the patients. Oligoclonal bands were not detected in any of the sera or CSF. Antibodies to peripheral nerve tissue were detected in approximately 30% of the patient sera, but could not be detected in the CSF.

Increased IgG secretion by unstimulated mononuclear cells in active multiple sclerosis and functional assessment of the T8 subset

Unseparated mononuclear cells (10(5) cells/well) were cultured both in the presence and absence of pokeweed mitogen (PWM), and IgG secretion was measured by radioimmunoassay. In unstimulated cultures, levels of IgG secretion were found to be higher in a group of patients with multiple sclerosis (MS) than in control groups of healthy individuals or patients with other neurologic diseases (OND). By contrast, PWM-induced IgG secretion was similar in MS patients and in controls. In MS patients, levels of IgG secretion greater than 2500 ng/ml in unstimulated cultures were present in 29 (58%) of 50 patients with active disease and in only 3 (14%) of 21 patients with inactive MS (P less than 0.01; MS active vs inactive). Furthermore, levels of IgG secretion in unstimulated cultures were higher in patients who had abnormalities of circulating T-cell subsets consisting of reduced numbers of suppressor/cytotoxic (T8) cells and elevated helper:suppressor (T4:T8) ratios. In additional experiments using isolated populations of T-cell subsets, T8 cells from MS patients who had low percentages of circulating T8 cells were found to suppress PWM-induced IgG secretion by autologous cells to a similar extent as controls, suggesting that in vitro, T8 cells function normally in these patients. In vitro IgG secretion by unstimulated mononuclear cells in MS appears to be a further reflection of abnormal immune regulation in this disease.

Is progressive multifocal leukoencephalopathy associated with intrathecal IgG synthesis?

Examination of the cerebrospinal fluid by isoelectric focusing was done in 2 cases of progressive multifocal leukoencephalopathy (PML). The diagnosis was confirmed at autopsy in one case. IgG oligoclonal bands were found in both, suggesting that there was intrathecal immunoglobulin synthesis. Production may be due to a specific intrathecal response to papova virus or to IgG oligoclonal formation by lymphoma cells confined to the central nervous system or to a specific immune response to tumor cell antigens.

Suspected and clinically definite multiple sclerosis: the relationship between CSF immunoglobulins and clinical course

CSF immunoglobulins were examined in 103 patients with clinically definite multiple sclerosis, 106 patients with either suspected or progressive possible multiple sclerosis and 72 patients with other neurological diseases. Raised CSF IgG index and oligoclonal banding were found in 71% and 75% of clinically definite multiple sclerosis patients respectively and both tests were abnormal in 11% of patients with other neurological diseases. The CSF IgG index and the presence of oligoclonal IgG did not relate to the severity or duration of established disease in these patients. In patients with suspected and progressive possible multiple sclerosis, both a raised IgG index and the presence of oligoclonal banding were found significantly more frequently than in the OND group. Abnormalities of these parameters were significantly correlated with the presence of an abnormal evoked response in these patients (chi 2 = 10.16 p less than 0.01). When 47 patients with suspected multiple sclerosis were studied prospectively the presence of oligoclonal banding at presentation was associated with development of further disease activity.

Two-dimensional electrophoresis of cerebrospinal fluid proteins in normal and pathological conditions

The two-dimensional polyacrylamide gel electrophoresis technique has been adapted for the analysis of human cerebrospinal fluid proteins. Proteins were detected by Coomassie brilliant blue stain and/or by silver stain. Highly reproducible protein patterns were obtained. We analyzed ten normal CSF specimens, thirty pathological CSF specimens and the corresponding sera. We mapped the protein patterns observed by examination of serum/CSF differences and by immunofixation. Preliminary observations on the changes in protein patterns in CSF specimens from patients with neurological disorders are reported.

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.

Cerebrospinal fluid in multiple sclerosis: relationships between immunoglobulins, leucocytes and clinical features

Cerebrospinal fluid (CSF) from 120 patients with multiple sclerosis was analyzed by polyacrylamide gel electrophoresis, as well as routine laboratory microscopy and assays of total protein and immunoglobulin G (IgG). Negative correlations were found between leucocyte counts and patient age, duration of disease and time from last clinical relapse. There was a positive correlation between the leucocyte count and amount of gammaglobulin. A correlation between gammaglobulin content and degree of disability was found. With increasing duration, the gammaglobulin concentration rose only if there was increasing disability. In terms of correlations with clinical features, differences existed depending on whether IgG was assayed immunologically or by electrophoresis and densitometry. Evidence of increased blood: CSF barrier permeability (transudation of high molecular weight proteins) was found in patients with progressive disease. The presence of oligoclonal bands was the CSF abnormality most frequently encountered.

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.

Abnormalities of serum and plasma components in patients with multiple sclerosis

Qualitative and quantitative abnormalities in protein and non-protein components of serum and plasma in patients with multiple sclerosis have been the subjects of numerous reports. In this review many of the more recent observations are documented and evaluated. It is concluded that at present the welter of information that has been gathered does not contribute in any major, coherent way to our understanding of the etiology or pathogenesis of the disorder. Several of the abnormalities that have been observed may be future candidates for biochemical markers for multiple sclerosis; at present none is sufficiently reliable, distinctive or easily performed to warrant the status of a useful diagnostic or prognostic test.

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.

CFS oligoclonal bands in MS and other neurological diseases detected by agarose isoelectric focusing and electrophoresis

Agarose gel isoelectric focusing (IEF) and electrophoresis (EF) were compared for detection of CSF oligoclonal bands in multiple sclerosis (MS) and other neurological diseases. The CSF IgG/albumin ratio, the IgG-Index and the IgG synthesis per day in the CNS were also considered. IEF was highly sensitive, revealing oligoclonal bands in 100% of CSF from 40 clinically definite MS, while EF had a sensitivity of 70%. In 90 patients with other neurological diseases, IEF revealed oligoclonal bands in 25.5%, EF in 11.1%. The IgG-index was the most sensitive of the quantitative parameters.

Isoelectric focusing of CSF proteins and the future evolution of multiple sclerosis: a clinical follow-up

A clinical follow-up covering a period of 5-10 years after onset was performed in 150 patients with optic neuritis or other potential onset symptoms of MS. Thin-layer isoelectric focusing had been used for the initial CSF-protein analysis. No evidence for a more probable alternative diagnosis appeared in 147 patients while a non-MS diagnosis was established in 3 patients. Among these 147 subjects the planned follow-up was accomplished in 131 patients, but not in 16. An evolution into clinically definite MS occurred in 59 subjects, in whom oligoclonal CSF immunoglobulin was found in 92%. Further clinical activity without spatial dissemination--i.e. lesser degrees of diagnostic probability for MS--were found in 35 patients in whom oligoclonal CSF immunoglobulin components were detected in 86%. Among the 131 patients with a complete follow-up, 45 remained free from further clinical activity; oligoclonal CSF immunoglobulin components occurred in 40% of these patients. The frequency of further clinical activity with or without spatial dissemination was significantly higher in subjects exhibiting oligoclonal CSF immunoglobulin components than in those without such changes.

An evaluation of cerebrospinal fluid oligoclonal banding confirmed by immunofixation on agarose gel

The cerebrospinal fluid (CSF) from 115 consecutive patients undergoing diagnostic lumbar puncture or myelography was examined to determine the usefulness of immunofixation, following agarose gel electrophoresis, in the detection of oligoclonal IgG. All electrophoretic patterns were evaluated with and without immunofixation, and the interpretation of 9% of specimens was altered by immunofixation. The demonstration of oligoclonal IgG was shown to be more reliable in the diagnosis of multiple sclerosis than other indices of intrathecal synthesis of IgG. It is concluded that immunofixation should be used routinely when examining CSF for oligoclonal banding.

Oligoclonal IgG bands in cerebrospinal fluid in various neurological diseases

We studied the frequency of oligoclonal immunoglobulin G bands in the cerebrospinal fluid (CSF) of patients with various neurological diseases. We used a micromethod employing sodium dodecyl sulfate polyacrylamide gel electrophoresis that required only 50 microliters of unconcentrated CSF. Oligoclonal bands were detected in the CSF of 95% of the patients with multiple sclerosis, 90% with subacute sclerosing panencephalitis, and 100% with herpes simplex encephalitis, but less frequently in other central nervous system infections. No oligoclonal bands were detected in the CSF of patients with Parkinson, Huntington, Creutzfeldt-Jakob, or herniated disc diseases. Bands were detected in some patients with Alzheimer disease, cerebrovascular accident, idiopathic vertigo, idiopathic seizures, amyotrophic lateral sclerosis, polyneuropathy, and central nervous system glioma. Patients with other conditions infrequently had positive bands. The determination of oligoclonal bands is a useful aid in the diagnosis of multiple sclerosis, subacute sclerosing panencephalitis, and herpes simplex encephalitis. The presence of oligoclonal bands indicates an immunological response but is not diagnostic for a particular condition.

Antibody synthesis within the central nervous system: comparisons of CSF IgG indices and electrophoresis

VARIOUS LABORATORIES HAVE REPORTED DIFFERING SUCCESS RATES IN THEIR ABILITY TO DETECT INTRATHECAL SYNTHESIS OF ANTIBODY WHEN COMPARING THE INDEX OF [FORMULA: see text] with electrophoretic analysis. We selected 44 patients in the borderline area of minimal and/or equivocal abnormality by IgG index. Electrophoretic analysis (on polyacrylamide gels for oligoclonal gamma globulin pattern) of parallel specimens was performed at the same time. The number of samples giving a normal index but showing oligoclonal bands varied between 34% and 43% depending on the cut-off point. The views about normal barrier functions underlying such indices are discussed with particular reference to the pathophysiology of the blood-CSF barrier.

Occurrence of oligoclonal bands in multiple sclerosis and other CNS diseases

The results of cerebrospinal fluid agarose gel electrophoresis in 300 consecutive patients were correlated with neurological examinations and diagnoses, other cerebrospinal fluid studies, and the results of evoked potential examinations. The presence of oligoclonal bands was the most sensitive test for multiple sclerosis (MS); bands were present in from 100% (11/11) of patients with definite MS to 82% (27/33) of those with possible MS (classified by McAlpine criteria). The visual evoked response was the next most sensitive study. Thirty-eight patients without MS or related disorders had bands in the IgG region. Three patients had plasma cell dyscrasias. Seven patients had thick single bands. Single bands did not correlate with chronic polyneuropathy but appeared to be an artifact of storage. Twenty-eight patients had active neurological disease, including cerebral infarction (in 5), viral infection (in 4), remote effect of carcinoma (in 4), and acute and chronic polyneuropathies (in 6). In acute illnesses (i.e., vascular insults), repeat electrophoresis showed disappearance of bands. In continually active disease, bands persisted. These results indicate that the presence of oligoclonal bands provides sensitive supporting evidence for the diagnosis of MS but that bands may be present in other disorders, including those not directly related to infection or abnormal immune response. The data suggest that oligoclonal bands may represent an immune response to neurological injury that is prominent in disorders with a particularly intense or continuous antigenic stimulus.

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.

Demonstration of cerebrospinal fluid oligoclonal banding in neurologic diseases by agarose gel electrophoresis and immunofixation

Demonstration of an oligoclonal immunoglobulin pattern in cerebrospinal fluid by a commercial agarose gel electrophoresis system and immunofixation were evaluated in the service clinical laboratory of a university hospital. In 303 patients, 45 with clinically definite multiple sclerosis and 209 with other neurologic diseases, the sensitivity of oligoclonal banding for multiple sclerosis was 71%, and the specificity, 83%. Oligoclonal banding was frequent in inflammatory disease, tumor/pseudotumor or vascular diseases of the central nervous system (35%, 36% and 26%, respectively) and less frequent in degenerative central nervous system disease and peripheral neuropathy (5.2% and 15%). No patient with non-neurologic disease had oligoclonal banding. The addition of an immunochemical step (immunofixation) did not increase sensitivity and only minimally increased specificity. It did permit distinction in selected cases between immunoglobulin and other molecules with identical electrophoretic mobility.

On the relationship of CSF pleocytosis to immunoglobulin levels as estimated by different techniques

One might expect a positive correlation between the number of CSF lymphocytes and the relative amount of CSF IgG, especially in cases of local synthesis of IgG within the CNS. However, previous attempts at correlating the number of CSF lymphocytes with IgG levels have yielded varying results. Since it is known that the estimation of CSF IgG levels can vary according to the method of immunoglobulin determination used, we decided to perform the analyses by three separate methods: (1) the commonly used, immunoprecipitation technique of radial immunodiffusion; (2) physico-chemical separation on the basis of hydrated size/charge using alkaline electrophoresis through the molecular sieving effects of polyacrylamide gels, followed by densitometry of the gamma region of Coomassie Blue-stained proteins; (3) separation into constituent Ig heavy chains and light chains on the basis of unfolded chain lengths by molecular sieving using sodium dodecyl sulphate (SDS), followed by densitometry of heavy chains of immunoglobulins having been labelled with the fluorescent dye dansyl chloride. Our results show a correlation of white count with the latter two techniques but not the former. Possible reasons for discrepancies in the literature are discussed with regard to the peculiar physical properties of the selected CSF IgG molecules.

Agarose isoelectric focusing of unconcentrated CSF and radioimmunofixation for detection of oligoclonal bands in patients with multiple sclerosis and other neurological diseases

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

Specificity of immunoglobulins synthesized within the central nervous system in neurosyphilis

Cerebrospinal fluid from four patients with serologically and clinically verified neurosyphilis contained oligoclonal bands when analysed by isoelectric focusing. By antiserum immunofixation these bands consisted by IgG, and by antigen immunofixation and autoradiography the bands were shown to contain treponemal antibodies. Treponemal antibodies synthesized within the CNS were also detected in polyclonal CSF IgG fractions in two of the patients. In one patient with neurosyphilis followed over 2.5 years, local synthesis of IgM and IgA disappeared within 1 year after treatment, while IgG synthesis persisted. In this patient, besides treponemal antibodies, antibodies against herpes simplex virus were also detected in oligoclonal and polyclonal IgG fractions of CSF. The presence of treponemal antibodies synthesized within the CNS was identified in 2 of 16 controls with negative serological tests for syphilis. This might reflect a previous contact with apathogenic treponemes, and the intrathecal antibody synthesis might be a result of an unspecific activation of memory lymphocytes in CNS.

Oligoclonal IgG in the cerebrospinal fluid of guinea pigs with acute experimental allergic encephalomyelitis

The cerebrospinal fluid (CSF) of guniea pigs with experimental allergic encephalomyelitis was examined for the presence of oligoclonal IgG using polyacrylamide gel electrophoresis. Oligoclonal IgG (greater than or equal to 2 bands) was seen in the CSF obtained from 3/4 animals with experimental allergic encephalomyelitis induced by myelin basic protein and 2/3 with spinal cord-induced disease. It was not seen in CSF of 3 non-sensitized, 4 adjuvant-sensitized and 7 liver-sensitized guinea pigs. Scanning of stained gels confirmed the oligoclonal pattern. The bands were found in the region of gels which bound [125I]Staphylococcal Protein A. The data demonstrate that a non-infectious inflammatory reaction within the central nervous system can result in an oligoclonal IgG pattern in the CSF.

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.

Antibodies in oligoclonal immunoglobulins in CSF from patients with acute cerebrovascular disease

Thin-layer polyacrylamide gel isoelectric focusing (PAG IEF) of CSF and serum, and subsequent immunofixation with viral and structural brain components followed by autoradiography revealed in eight out of nine selected patients with oligoclonal CSF IgG and cerebrovascular disease local synthesis within the CNS of antibodies against one or more of the viruses tested: six patients against measles, five against herpes simplex virus type 1, and two against varicella virus. This finding may reflect a polyclonal B cell activation secondary to brain damage and elaboration of certain structural brain components. None of the patients had local synthesis of antibodies against the other viruses tested (mumps, rubella and cytomegalovirus), or against structural brain components (crude saline, lipid-proteolipid, myelin basic protein extracts from human brain and purified bovine myelin basic protein).

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.

Viral antibodies in oligoclonal and polyclonal IgG synthesized within the central nervous system over the course of mumps meningitis

The occurrence of viral antibodies in relation to IgG separated by thin-layer polyacrylamide gel isoelectric focusing was studied in CSF and serum from 24 patients with mumps meningitis by immunofixation with viral antigens and autoradiography. Eleven of the patients displayed on the autoradiograms evidence of locally in the central nervous system synthesized mumps virus antibodies which were related to oligoclonal IgG bands in all 5 patients who displayed this CSF abnormality, otherwise to polyclonal IgG bands. Local synthesis of mumps virus antibodies was detectable in 43% of specimens obtained 1-13 days after onset, and in 75% obtained 27-47 days after onset. Only one patient displayed local synthesis of antibodies to other viruses (measles and herpes simplex) which could then be traced to polyclonal IgG bands.

Viral antibody activity of oligoclonal and polyclonal immunoglobulins synthesized within the central nervous system in multiple sclerosis

Thin-layer polyacrylamide gel isoelectric focusing (PAG IEF), a very high capacity method for separating immunoglobulins (Ig), was performed on cerebrospinal fluid (CSF) and serum. It was followed by antigen immunofixation with measles, mumps, herpes simplex (HSV), and rubella virus antigens and anti-human Ig autoradiography in order to demonstrate viral antibodies in separated Ig zones. Two of 11 control patients and 21 of 25 patients with multiple sclerosis (MS) displayed one or more zones of viral antibodies in the CSF without any counterpart, or with distinctly fainter zones, in the serum. Such reaction patterns were taken to indicate the possibility of intrathecal antibody synthesis. Antibody synthesis to measles was found in one to five zones in 76% of the patients with MS; antibody zones were found to HSV in 36% of the patients, to mumps in 12%, and to rubella in 12%. In 36% of the patients, two or three different antibody specificities (of which one was always measles) were found simultaneously in individual autoradiogram zones. For all viral antibodies detected in the CSF autoradiograms, their counterparts in oligoclonal or polyclonal IgG zones (or both) were demonstrable by PAG IEF of the corresponding CSF. The majority of patients with MS also had one or more oligoclonal CSF IgG zones without known antibody specificity. Antigen immunofixation and autoradiography are mainly qualitative. It is not known whether the viral antibodies present in oligoclonal or polyclonal IgG zones in MS CSF reflect a polyclonal B cell activation, a disease-specific immune reaction, or both.

The significance of abnormal immune responses in patients with multiple sclerosis

Early diagnosis of multiple sclerosis (MS) may be assisted by tests for the abnormal immune responses of the central nervous system (CNS) including oligoclonal IgG bands in the cerebrospinal fluid (CSF), increased CNS IgG synthesis, increased CNS antibody synthesis against multiple viruses and increased numbers of enlarged lymphoid cells in the CSF. Alterations in immunological responses are important in the pathogenesis of MS. Further studies are needed, however, to identify the antigen(s) and/or antibodies responsible for oligoclonal IgG in the CSF of MS patients. Also, the cause(s) for the other immunological abnormalities with diagnostic importance need to be identified. The increased synthesis of antibodies against multiple unrelated viruses suggests generalized alteration in the immune regulatory system. The etiology of MS might be multifactorial involving abnormal immunological responses, possibly precipitated by infectious agents acquired during childhood by genetically susceptible individuals. The immunological responses including alterations in myelin basic protein concentration, antimyelin antibody and immune complex activities in CSF, and in vitro stimulation, suppression and migration inhibition of blood lymphocytes appear to correlate with stage of MS and severity of CNS damage. Some of the tests may become useful in estimating the prognosis of the disease. Longitudinal studies are needed to clarify the sensitivity of the diagnostic and prognostic immunological tests and etiological significance of these abnormalities in MS.