IgG subclasses, barrier function for albumin and production of immunoglobulin G in the central nervous system

Distinct heterogeneity of IgG immune response in cerebrospinal fluid (CSF) detected by isoelectric focusing (IEF) with extended immunofixation

An optimized automated IEF procedure in polyacrylamide micro gels and immunofixation with 10 monospecific antibodies against some fragments of the IgG molecule and against the whole IgG isotypes IgG(1), IgG(2), IgG(3), IgG(4), respectively, detected oligoclonal bands (OBs) within acid, neutral, and alkaline ranges of the gels. Accuracy and reliability of the OB assay for detection of an intrathecal IgG synthesis proved to be higher with immunofixation than with silver staining of bands precipitated by trichloroacetic acid. CSF OBs were specified as lambda or kappa IgG subfractions, respectively, duplex IgGs precipitated with anti-lambda, anti-kappa, and anti-Fc antibodies at the same pI. Most of OBs were classified as belonging to either IgG(1), IgG(2), IgG(3), or IgG(4) isotypes in CSF. The IEF procedure additionally allowed the discrimination of both free light chains and possible "free" heavy gamma chain fragments in CSF, when immunofixation was done with monospecific antibodies against both light chains and gamma chain fragments (e.g. anti-F(ab')(2), anti-Fd, anti-Fc, anti-C(H)2). The results pointed out a distinct heterogeneity of the IgG immune response in human CSF. The IEF procedure with extended immunofixation is recommended for completion of the basic laboratory procedures used in neuroimmunology in order to discriminate inflammatory processes in human CNS.

Intrathecal synthesis of IgG subclasses in multiple sclerosis and in acquired immunodeficiency syndrome (AIDS)

Serum and cerebrospinal fluid (CSF) of 50 neurological patients (24 multiple sclerosis (MS), ten acquired immunodeficiency syndrome (AIDS) and 16 other neurological diseases (OND)) and ten controls were analyzed by enzyme-linked immunosorbent assay (ELISA) for IgG subclass quantification and for the calculation of intrathecal synthesis (ITS). Total IgG was determined by two methods: electroimmunodiffusion (EID) and ELISA. A highly significant correlation was established between both methods. The existence of ITS was proved by the IgG/albumin ratio, the IgG index, Tourtellotte's formula, and Schuller's formula. In AIDS patients all IgG subclasses showed an increase in the CSF, whereas in sera only the IgG1 was significantly increased. CSF of MS patients showed a predominant increase of IgG1 whereas no significant modification of IgG subclasses was observed in sera. In most of the AIDS patients there was an ITS of IgG1, IgG3 and IgG4, but rarely (3/10) IgG2. In contrast, a polyclonal ITS of IgG was exceptional (1/24) in MS patients. No significant correlation could be established between clinical data and IgG subclass ITS in MS. The variations of each IgG subclass in serum and in ITS were not significantly correlated. Measurement of each IgG subclass and calculation of ITS seems essential in order to analyze any subclass antibody repertory inside the central nervous system.

Cobalamin binding proteins (haptocorrin and transcobalamin) in human cerebrospinal fluid

The unsaturated cobalamin binding capacity of transcobalamin and haptocorrin was studied in cerebrospinal fluid (CSF) and plasma (P) from 37 reference individuals. These comprised 27 males and 10 females who underwent minor surgery in spinal anaesthesia. The 5th and 95th percentiles were as follows: P-Transcobalamin 300-870 pmol/l (median 550 pmol/l); CSF-Transcobalamin 90-540 pmol/l (median 194 pmol/l); P-Haptocorrin 75-290 pmol/l (median 159 pmol/l); CSF-Haptocorrin 10-41 pmol/l (median 21 pmol/l). No sex difference was found between the levels of haptocorrin or transcobalamin in plasma or cerebrospinal fluid. A positive correlation between P-Transcobalamin and CSF-Transcobalamin was found, whereas no correlation between P-Haptocorrin and CSF-Haptocorrin values was found. The plasma/CSF ratios of transcobalamin, haptocorrin, albumin and IgG indicated that the binders may be synthetized into the cerebrospinal fluid or are actively being transported into the cerebrospinal fluid.

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.

Cerebrospinal fluid protein findings in cervical syndromes classified by myelography, and in multiple sclerosis

Determinations of cerebrospinal fluid (CSF) albumin, IgG, albumin blood brain barrier (BBB) permeability and local IgG synthesis indexes in CNS were carried out on 85 patients with various neck, shoulder and upper extremity pain syndromes. CSF was obtained by lumbar puncture in 29, and by lateral neck puncture in 56 of the patients. The patients were classified into 3 different groups according to varying severity of degenerative changes, or cavitation verified by myelography. CSF protein patterns in these patients were compared with lumbar CSF findings in 18 patients with multiple sclerosis. CSF protein changes in patients with abnormal myelographic findings were slight. Protein values were clearly more abnormal in lumbar CSF than in cervical CSF, probably due to a retardation of the CSF flow. Only 3 of 62 patients with a narrowing of the cervical spinal canal had pathological values for IgG synthesis or BBB permeability indexes. On the other hand 14 of 18 patients with multiple sclerosis had abnormal, high values for the IgG index. Thus the present results suggest that investigation of the CSF protein pattern has value in differential diagnosis between patients with multiple sclerosis and degenerative diseases of the cervical spine.

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.

Blood-brain barrier integrity in patients with cerebral infarction investigated by computed tomography and serum-CSF-albumin

Measurements of CSF-albumin, and S/CSF-albumin in two groups of patients with small and large infarcts failed to show BBB damage to albumin in about one half of the patients. No significant difference was found between the two groups of patients in regard to the above-mentioned parameters. The localization of the infarcts (close to the CSF or deep in the brain) did not influence the S/CSF-albumin. No correlation was found between the S/CSF-albumin and the time interval between the onset of the stroke and the lumbar puncture within 96 h. Some suggestions are put forward to explain the discrepancies between the CT-scan and S/CSF-albumin in the assessment of BBB damage.

Rapid immunoturbidimetric assay of albumin and immunoglobulin G in serum and cerebrospinal fluid with an automatic discrete analyser

A method is presented to determine albumin and immunoglobulin G (IgG) in serum and cerebrospinal fluid (CSF) with an automatic discrete analyser. Concentrations of albumin and IgG in serum and CSF are compared with values obtained by radial immunodiffusion (RID). Ratios of albumin in CSF over albumin in serum and the so-called IgG index are calculated. Ratios obtained with the discrete analyser and with the RID are compared and discussed with respect to clinical diagnosis.

Immunoglobulin G heavy chain (Gm) allotypes in multiple sclerosis

Serum samples from 70 Caucasian patients with multiple sclerosis were typed for nine Gm markers. Significant association was found with the Gm 1,17;21 phenotype, and the relative risk for individuals with this phenotype was calculated at 3.6. The data indicate that Caucasians positive for Gm 1,17;21 are almost four times more likely to develop multiple sclerosis than those without this phenotype.