Polyacrylamide disc electrophoresis of cerebrospinal fluid and cerebral cyst fluids

IgG ratios and oligoclonal IgG in multiple sclerosis and other neurological disorders

The findings are reported of various CSF abnormalities, including IgG indices and oligoclonal IgG, in 160 patients with multiple sclerosis of differing diagnostic certainty and 146 patients with other neurological disorders. An abnormal IgG index, defined as the ratio of IgG/albumin in CSF to that in serum, has been found in 77.7% of definite MS cases, falling to a figure of 32.1% in the single lesion group. A tendency, reported previously, for IgG levels to be higher in disabled patients, particularly those with a short history or early onset, has been confirmed. Oligoclonal IgG, on the other hand, has been found in 56% of definite MS cases, less frequently than in most other reported series. Analysis of the literature suggests considerable variability in the finding of oligoclonal IgG in other than definite MS, and in other neurological disorders. The possibility that subjective factors are partly responsible for this variability, rather than discrepancies in patient selection requires consideration, and suggests that CSF electrophoresis and IgG estimations are complementary aids in the diagnosis of multiple sclerosis. Differences have been expressed regarding the relationship of oligoclonal IgG to clinical parameters of the disease. Further sequential analysis of the development and variability of the oligoclonal pattern in MS is required.

The nature of 'oligoclonal' bands in cerebrospinal fluid of patients with multiple sclerosis

The presence of 'oligoclonal' IgG in cerebrospinal fluid is increasingly being used as a confirmatory test in the diagnosis of multiple sclerosis. Visual inspection of stained gels following electrophoresis is currently the routine method of analysis. In order to minimise subjective error and increase the sensitivity of this test, a labelled antibody technique for visualising IgG has been developed. The results of tests on cerebrospinal fluid samples from 49 patients with multiple sclerosis suggest that the incidence of 'oligoclonal' bands containing IgG may be very much lower than previously supposed. The implications of this unexpected finding are discussed.

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.

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.

Effect of sample preparation on cerebrospinal fluid protein patterns in polyacrylamide gels

The method of preparing CSF and dilute serum samples for polyacrylamide gel electrophoresis has a marked effect on the pattern of the resolved proteins. The incorporation of sucrose or glycerol into the sample seriously impairs the quality of the resolution and affects the actual number of bands resolved and the relative mobility of certain proteins. The use of sucrose as an anti-convection medium in dense samples such as serum and CSF is not recommended.

Oligoclonal immunoglobulins and plasma cells in spinal fluid of patients with multiple sclerosis

A new modification of polyacrylamide gel electrophoresis (PAGE) was applied to cerebrospinal fluid proteins from patients with multiple sclerosis (MS). The same spinal fluids were also examined by a cytological technique. Over 90% of patients with clinically definite or early probable or latent MS showed abnormal PAGE patterns in the form of oligoclonal gammaglobulin bands. Reactive (atypical, large) lymphocytes or typical plasma cells were found in some patients. In all such cases an oligoclonal pattern was present. The findings of oligoclonal bands provides valuable supporting evidence for the diagnosis of MS in the less definite clinical categories.