Glutaraldehyde-enhanced immunofixation: a sensitive new method for detecting oligoclonal immunoglobulin M

Cerebrospinal fluid oligoclonal IgM test in routine practice: Comparison with quantitative assessment of intrathecal IgM synthesis

BACKGROUND

Intrathecal IgM synthesis demonstrated either as cerebrospinal fluid (CSF)-restricted oligoclonal (o-) IgM bands or calculated using various formulas has been linked to more aggressive multiple sclerosis (MS) course. However, the proportion of MS patients showing intrathecal IgM synthesis varies largely between studies. We aimed to explore the relation between different formulas and results of o-IgM, and to assess the frequency of o-IgM bands in an unselected series of samples.

METHODS

432 samples were analyzed for o-IgM, o-IgG and quantitative measures of IgM and IgG synthesis. IgM index and formulas of Reiber, Auer and Öhman were compared to the result of the o-IgM test.

RESULTS

At the cut-off commonly used, the non-linear formulas for intrathecal synthesis were specific (>94%) but rather insensitive (<40% even at a cut-off of 4 CSF-restricted bands) compared to o-IgM. No significant difference was noted in the performance of different formulas. At a cut-off of 4 bands, 61% of MS patients, but none of the controls were positive for o-IgM.

CONCLUSIONS

Formulas for intrathecal IgM synthesis are insensitive compared to o-IgM. We propose to evaluate samples with 2 or 3 extra-CSF IgM bands as borderline and only samples with 4 or more as definitely positive.

An improved, ultrasensitive method for the detection of IgM oligoclonal bands in cerebrospinal fluid

A new, 10-fold more sensitive method, based on an improved immunofixation technique, has been devised to detect oligoclonal IgM bands in unconcentrated cerebrospinal fluid (CSF). Using agarose gel electrophoresis, 5 microliters of an unconcentrated sample containing oligoclonal bands was separated and blotted on to a polyvinyldifluoride membrane. To visualise the pattern, a peroxidase-labelled double-antibody technique was used. No prior concentration of CSF was needed and the process required only 5 h. The technique may prove very useful in diagnosing an early intrathecal immune response.

Evidence for persistent enterovirus infection of the central nervous system in patients with previous paralytic poliomyelitis

It has been suggested that late onset neurological deterioration after poliomyelitis may be due in some cases to persistent poliovirus infection of the central nervous system. In view of this, we decide to determine whether polioviruses and other enteroviruses can persist in the central nervous system. In a previous study, one of us (M.K.S.) reported serological evidence of persistent poliovirus infection of the central nervous system (CNS) in a proportion of these patients. We have now studied cerebrospinal fluid (CSF) from these patients for the presence of enterovirus RNA sequences using the polymerase chain reaction (PCR). Enteroviral RNA was detected in 3 of 24 patients with a clinical diagnosis of post-polio syndrome, but in none of 36 patients with stable poliomyelitis, and none of 36 patients with other neurological conditions of noninfective origin. All 3 patients in whom viral RNA was detected had high intrathecal levels of poliovirus-specific oligoclonal IgM bands. In a second study we examined formalin-fixed postmortem CNS tissue from 7 patients with a history of paralytic poliomyelitis. Enterovirus RNA was detected in tissue from the spinal cord from 3 patients, but not in the cerebral cortex. We are now conducting a larger prospective, blind study of patients with evidence of late deterioration. Analysis of the first 30 patients studied revealed the presence of enterovirus RNA in CSF of 1 of 4 patients with unexplained late-onset post-polio weakness, 1 of 6 with some evidence of clinical deterioration, but none of 20 without inexplicable signs of post-polio weakness. Enteroviral RNA was also detected in spinal cord from 2 of 3 patients who died from other causes during this study. These studies provide virological evidence that enteroviruses may persist in the CNS of man. Further study is required in order to understand fully the biological and clinical significance of these findings.

A high-sensitivity immuno-chemiluminescence technique for detection of oligoclonal IgG and IgM in unconcentrated cerebrospinal fluid

A method is described for detection of oligoclonal IgG and IgM in unconcentrated cerebrospinal fluid (CSF). The proteins were separated by agarose gel electrophoresis and transferred to cellulose nitrate membranes. A double antibody technique with a peroxidase conjugated secondary antibody was used to detect the protein. Bound secondary antibody was visualized by autoradiography using chemiluminescence (ECL) reagent. The procedure presented here allows examination of oligoclonal bands of IgG and IgM in less than 6h. The detection limit for a single band was approximately 10pg and the results were in complete agreement with those achieved by isoelectric focusing (Phast System) and subsequent immunofixation. In 9 of the samples oligoclonal IgM was also detected.

Intrathecal synthesis of IgM and IgA in neurological diseases: comparison of two formulae with isoelectric focusing

The intrathecal IgM and IgA immune response was studied by detecting oligoclonal IgM and IgA bands in CSF and by determining both the IgM/IgA indices as well as the intrathecal production of IgM and IgA by the Reiber formula. A good correlation was found between the demonstration of oligoclonal IgM (r = 0.890) and IgA bands (r = 0.927) and the Reiber formula. Compared with the finding of oligoclonal IgM/IgA bands calculation of an intrathecal IgM/IgA synthesis by the Reiber formula was less sensitive (86%). In two out of 22 controls and in 12 of 19 patients with polyradiculitis IgM and IgA indices were elevated while the other evaluation methods were negative. Even though oligoclonal IgM and IgA bands are considered to be a useful diagnostic tool in detecting intrathecal synthesis of IgM and IgA, i.e. in meningoencephalitis or neuroborreliosis for clinical practice, the Reiber formula provides reliable results. Detection sensitivity of assays for CSF-IgM and -IgA should be at least 1.0 mg/l.

Intrathecal IgM response in disseminated cerebrospinal metastasis from malignant melanoma

Neurological complications are a major cause of morbidity and mortality in patients with disseminated malignant melanoma. We have studied and correlated clinical and cerebrospinal fluid (CSF) findings in 20 patients with central nervous system metastases from malignant melanoma including 8 patients with metastatic meningeal melanomatosis (MMM) and 12 patients with solid cerebral metastases (SCM). The putative CSF tumor markers, fibronectin and beta 2-microglobulin, were elevated significantly in MMM but not in SCM patients. A prominent increase in the IgM index, which reflects intrathecal B-cell stimulation, and a rise of IgG index, interleukin-6, and tumor necrosis factor-alpha in MMM patients provide preliminary evidence for a local intrathecal immune response triggered by melanoma cell invasion of the subarachnoid space.

A characteristic ganglioside antibody pattern in the CSF of patients with amyotrophic lateral sclerosis

Paired cerebrospinal fluid and serum samples of patients with amyotrophic lateral sclerosis (n = 35) revealed no consistent abnormalities of CSF cell count, CSF albumin, CSF IgG, CSF IgM, IgG or IgM index, or oligoclonal immunoglobulin band formation in the CSF. Determination of IgG and IgM CSF and serum antibodies to gangliosides GM1, GM2, GM3, AGM1, GD1a, GD1b, and GT1b showed a characteristic pattern which allowed the differentiation of amyotrophic lateral sclerosis from controls and from patients with other neurological disorders including multiple sclerosis. Specifically, patients with the disease had elevated CSF IgM antibodies to all gangliosides except AGM1. The lack of correlation between the CSF findings and corresponding serum antibodies suggests a chronic, compartmental, intrathecal immune response of low activity in amyotrophic lateral sclerosis. Whether this immune response is primary and of pathogenetic significance, or an epiphenomenon of neuronal degeneration, remains to be investigated.

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.

Are CSF or serum ganglioside antibodies related to peripheral nerve demyelination in neuroborreliosis, Guillain-Barré syndrome, or chronic inflammatory demyelinating polyradiculoneuropathy?

Cerebrospinal fluid (CSF) and serum IgG and IgM antibodies to seven gangliosides were determined in patients with neuroborreliosis (NB) (n = 20), Guillain-Barré syndrome (GBS) (n = 13), and chronic inflammatory demyelinating polyradiculoneuropathy (CIDP) (n = 10). The incidence of elevated antibodies was highest in NB and lowest in CIDP. Correlation between CSF and serum antibodies was only observed for IgG antibodies to GM1, GD1b and GT1b in GBS. The strong IgM antibody reactivity to gangliosides in the CSF of NB patients may be involved in the variety of neurological disorders attributed to Borrelia burgdorferi infection. Since one CIDP and three GBS patients had serologic evidence of prior or concurrent borrelia infection, this infection may belong to the infections that can trigger GBS or CIDP. The lack of specific ganglioside antibody patterns in these four patients suggests that ganglioside antibodies are not the link between Borrelia burgdorferi infection and the demyelination of peripheral nerves in GBS and CIDP.

A new qualitative method for detecting IgD in unconcentrated cerebrospinal fluid

We report a method which is capable of demonstrating the isoelectric focusing (IEF) pattern of immunoglobulin D in unconcentrated cerebrospinal fluid (CSF) samples containing as little as 0.1-0.5 ng of total IgD. The method used was an immuno-sandwich technique, with alkaline phosphatase enzyme amplification. Oligoclonal and polyclonal IgD patterns were seen in CSF samples. No cross-reactivity with other immunoglobulins (IgG, IgA and IgM) was detected.

Intrathecal immune response in patients with the post-polio syndrome

BACKGROUND

The syndrome of progressive muscular atrophy decades after acute paralytic poliomyelitis (post-polio syndrome) is not well understood. The theory that physiologic changes and aging cause the new weakness does not explain the immunologic abnormalities reported in some patients. An alternative explanation is persistent or recurrent poliovirus infection.

METHODS

We assessed the intrathecal antibody response to poliovirus and intrathecal production of interleukin-2 and soluble interleukin-2 receptors in 36 patients with the post-polio syndrome and 67 controls (including 13 who had had poliomyelitis but had no new symptoms and 18 with amyotrophic lateral sclerosis). Intrathecal antibody responses to measles, mumps, herpes simplex, and varicella zoster viruses were also determined.

RESULTS

Oligoclonal IgM bands specific to poliovirus were detected in the cerebrospinal fluid of 21 of the 36 patients with the post-polio syndrome (58 percent) but in none of the control group (P less than 0.0001). In quantitative studies there was evidence of increased intrathecal synthesis of IgM antibodies to poliovirus only among the patients with the post-polio syndrome; there was no increased synthesis of IgM to measles, mumps, herpes simplex, or varicella zoster viruses. The patients with post-polio syndrome had significantly higher mean (+/- SD) (cerebrospinal fluid levels of interleukin-2 and soluble interleukin-2 receptors than the controls (8.1 +/- 5.3 vs. 1.4 +/- 0.8 U per milliliter and 159.6 +/- 102.9 vs. 10.7 +/- 6.2 U per milliliter, respectively). The intrathecal synthesis of IgM antibodies to poliovirus correlated with the cerebrospinal fluid concentrations of interleukin-2 (P less than 0.0005) and soluble interleukin-2 receptors (P less than 0.001).

CONCLUSIONS

An intrathecal immune response against poliovirus is present in many patients with the post-polio syndrome. In some of these patients the recrudescence of muscle weakness may be caused by persistent or recurrent infection of neural cells with the poliovirus.

The predictive value of intrathecal immunoglobulin synthesis and magnetic resonance imaging in acute isolated syndromes for subsequent development of multiple sclerosis

The intrathecal synthesis of IgM in patients presenting with acute monosymptomatic syndromes may be relevant in predicting eventual progression to multiple sclerosis but has not been previously evaluated. We undertook a prospective 18-month combined clinical, cerebrospinal fluid, and magnetic resonance imaging study of 45 patients who had presented with acute isolated lesions of brainstem and spinal cord to evaluate the predictive value of intrathecal synthesis of IgM and IgG (through the detection of cerebrospinal fluid oligoclonal bands) and magnetic resonance imaging brain lesions at presentation, for the subsequent progression to multiple sclerosis. Results indicate that the highest risk of developing multiple sclerosis is seen in patients who are positive for oligoclonal IgM and IgG bands and who have disseminated cerebral white matter magnetic resonance imaging lesions at the initial presentation. Oligoclonal IgM bands predict progression to multiple sclerosis more frequently than oligoclonal IgG or magnetic resonance imaging alone. Our results confirm and further extend previous reports, and indicate that detection of cerebrospinal fluid oligoclonal IgM bands at presentation is a valuable prognostic indicator in patients presenting with acute isolated brainstem or spinal cord syndromes.

Isoelectric focusing of cerebrospinal fluid immunoglobulin G: an annotated update

A revised agarose isoelectric focusing method for detecting oligoclonal IgG in unconcentrated cerebrospinal fluid is presented. The technique is shown to be robust and reproducible and suitable for the detection of intrathecal IgG synthesis.

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.

A sensitive ELISA system for the rapid detection of virus specific IgM antibodies in the cerebrospinal fluid

The intrathecal production of IgM antibodies to different viral antigens was measured by a modification of ELISA that was both sensitive and specific. Suitably diluted CSF and homologous serum samples containing similar amount of IgM were examined, and a comparison of the photometric signals permitted the detection of specific antibodies secreted from activated lymphocytes into the CSF compartment during the course of viral infections of the central nervous system. Polyvinyl chloride (PVC) microtitre plates were activated by glutaraldehyde and then coated with different viral antigens. Test samples were incubated on these solid-phase antigens and virus-specific IgM antibodies were detected using a peroxidase-conjugated F (ab')2 fragment of anti-human IgM antibody to avoid interference from rheumatoid factors.

Intrathecal synthesis of IgM in neurological diseases: a comparison between detection of oligoclonal bands and quantitative estimation

Immunoglobulin (Ig) M concentration in cerebrospinal fluid (CSF) was measured in 30 reference subjects to determine reference ranges which were up to 0.41 mg/l for CSF IgM, 0.06 for IgM index, and 9 x 10(-4) mg/l for the Reiber empirical formula. Intrathecal IgM synthesis was then studied in 159 patients with different neurological diseases both by detecting CSF oligoclonal IgM bands and by determining the IgM index and Reiber's intrathecal IgM production values. At the same time, the state of blood-CSF barrier was evaluated in all patients by CSF polyacrylamide gel electrophoresis and by CSF/serum albumin ratio. Oligoclonal IgM bands were present mainly in patients with intrathecal humoral immune response, e.g. multiple sclerosis, other inflammatory nervous diseases, and infections of the central nervous system. Quantitative IgM ratios were, however, elevated in conditions not associated with local humoral immune response. Furthermore, quantitative ratios were elevated in patients with damaged blood-CSF barriers. Oligoclonal IgM bands are thus considered to be the most useful tool in detecting intrathecal synthesis of IgM.

Cerebrospinal fluid oligoclonal IgM in multiple sclerosis: analytical problems and clinical limitations

A method for detecting cerebrospinal fluid (CSF) oligoclonal IgM is described. Concentrated CSF was separated by agarose isoelectric-focusing and blotted with poly(vinyldifluoride). A double-antibody immunoperoxidase technique with avidin-biotin amplification was used to stain IgM. Special conditions were required to avoid cross-reaction with IgG. The method was applied to 99 patients on whom oligoclonal IgG analysis was performed. Positive IgM results occurred in 17 of the 27 patients positive for oligoclonal IgG, and in two patients negative for oligoclonal IgG, neither of whom had multiple sclerosis (MS). Fifteen of the patients positive for oligoclonal IgM had some IgM bands in their sera. Oligoclonal IgM was not found in the CSF of suspected MS patients without oligoclonal IgG, but occurred in several patients with oligoclonal IgG due to other diseases. As a test for MS, oligoclonal IgM was less sensitive than oligoclonal IgG and did not improve specificity.

Immunoglobulin M in the cerebrospinal fluid: an indicator of recent immunological stimulation

Using a sensitive new method for detecting oligoclonal immunoglobulin M (IgM) in unconcentrated cerebrospinal fluid (CSF), the intrathecal synthesis of IgM was correlated with that of free light chains in patients with multiple sclerosis, infections of the central nervous system and other neurological conditions. A strong correlation was found between the presence of oligoclonal IgM and that of free light chains in the CSF from patients with multiple sclerosis and infections of the central nervous system. No oligoclonal IgM response was observed in patients with non-inflammatory or non-infectious neurological conditions. This implies that oligoclonal IgM has the same diagnostic significance as free light chains.