Western blotting analysis in patients with MS using human brain vessels as antigen

Antiphospholipid antibodies: paradigm in transition

OBJECTIVES

This is a critical review of anti-phospholipid antibodies (aPL). Most prior reviews focus on the aPL syndrome (APS), a thrombotic condition often marked by neurological disturbance. We bring to attention recent evidence that aPL may be equally relevant to non-thrombotic autoimmune conditions, notably, multiple sclerosis and ITP.

ORGANIZATION

After a brief history, the recent proliferation of aPL target antigens is reviewed. The implication is that many more exist. Theories of aPL in thrombosis are then reviewed, concluding that all have merit but that aPL may have more diverse pathological consequences than now recognized. Next, conflicting results are explained by methodological differences. The lupus anticoagulant (LA) is then discussed. LA is the best predictor of thrombosis, but why this is true is not settled. Finally, aPL in non-thrombotic disorders is reviewed.

CONCLUSION

The current paradigm of aPL holds that they are important in thrombosis, but they may have much wider clinical significance, possibly of special interest in neurology.

Cell-derived microparticles and exosomes in neuroinflammatory disorders

All blood cells and the vascular endothelium shed microparticles (MP) from their plasma membranes when suitably stimulated, and assay of MP in patient blood has found increasing application to the monitoring of disease states. In addition, mounting evidence suggests that MP are not mere epiphenomena but play significant roles in the pathophysiology of thromboses, inflammation, and cancers. This chapter endeavors to summarize the limited number of studies thus far done on MP in neurological disorders such as multiple sclerosis (MS), transient ischemic attacks, and the neurological manifestations of antiphospholipid syndrome (APS). In addition, the chapter offers some plausible hypotheses on possible roles of MP in the pathophsyiology of these disorders, chiefly, the hypothesis that MP are indeed important participants in some neuropathologies, especially those which are ischemic in nature, but probably also inflammatory ones. The chapter also goes over the history and general principles of MP studies (e.g., assay methods and pitfalls), comparison with alternative methods (e.g., soluble markers of disease states), subclasses of MP (such as exosomes), and other topics aimed at helping readers to consider MP studies in their own clinical fields. Tables include a listing of bioactive agents known to be carried on MP, many of which were heretofore considered strictly soluble, and some of which can be transferred from cell to cell via MP vectors, for example certain cytokine receptors.

Epstein-Barr virus nuclear antigen-1 (EBNA-1) associated oligoclonal bands in patients with multiple sclerosis

Oligoclonal bands (OCBs) are frequently observed in the cerebrospinal fluid (CSF) of patients with multiple sclerosis (MS), but the target antigens of these antibodies remain unknown. We used antigen specific immunoblotting to determine whether Epstein Barr virus nuclear antigen-1 (EBNA-1) was a target of the OCBs in the CSF of patients with MS. Antibody indices (AIs) were measured by ELISA and calculated by the formula of Reiber and Lange which includes correction factors for both breakdown of the blood brain barrier and intrathecal polyclonal IgG synthesis. A distinctive oligoclonal antigen specific banding pattern for EBNA-1 was observed in 5/15 MS patients, but 0/12 controls (P=0.037, Fisher's Exact Probability). AIs in this EBNA-l positive subgroup were extremely high, comparable with levels observed in viral CNS infections. In one patient with EBNA-1 specific OCBs, EBNA-1 and a peptide 'equivalent', p62, were able to absorb a component of the total IgG. Our results suggest that in a subset of MS patients, EBNA-1 may be a major target of selected OCBs.

Molecular approach to find target(s) for oligoclonal bands in multiple sclerosis

OBJECTIVES

Oligoclonal bands are a characteristic finding in the CSF of patients with multiple sclerosis, yet their target antigen(s) remain unknown. The objective was to determine whether a filamentous phage peptide library could be employed to allow the oligoclonal bands to select their own target epitopes.

METHODS

CSF IgG antibody from 14 patients with multiple sclerosis and 14 controls was used to select individual phage clones from a bacteriophage library containing approximately 4 x 10(7) different hexamers expressed on its surface pIII protein. The amino acid sequence selected was deduced by sequencing the DNA of the genetically engineered insert.

RESULTS

In general, after three rounds of selection, CSF from both patients with multiple sclerosis and controls selected one to two consistent peptide motifs. Five out of 14 patients with multiple sclerosis, and one control, selected the amino acid sequence motif, RRPFF. Given 20 possible amino acids per position, the likelihood of five patients selecting the same linear five amino acid sequence is at most 1.6 x 10(-3), corrected for the number of clones sequenced. A GenBank computer search showed that this sequence is found in the Epstein-Barr Virus nuclear antigen (EBNA-1), and a heat shock protein alphaB crystallin. Human serum antibodies to a synthetic peptide containing RRPFF were virtually exclusively found in patients with prior infection by Epstein-Barr virus. Other studies have suggested a relation between Epstein-Barr virus infection and multiple sclerosis, including nearly 100% Epstein-Barr virus seropositivity among patients with multiple sclerosis and increased concentrations of antibody to EBNA in CSF of patients with multiple sclerosis. By antigen specific immunoblotting, antibodies to the RRPFF motif in the CSF were shown to correspond to a subset of oligoclonal bands in the CSF from the same patient.

CONCLUSION

This study shows that phage epitope display libraries may be used to select amino acid motifs which are potentially relevant to the pathogenesis of multiple sclerosis.

Clinical relapses and disease activity on magnetic resonance imaging associated with viral upper respiratory tract infections in multiple sclerosis

BACKGROUND

Although the risk of clinical attacks of multiple sclerosis seems to be significantly increased with viral upper respiratory tract infections (URTI), serological evidence for the reported association remains controversial. In addition, although MRI is six to 10 times more sensitive than clinical exacerbations in indexing disease activity, any possible association between URTI and MRI activity has yet to be investigated.

OBJECTIVES

To examine the relation between URTI and disease activity, in multiple sclerosis patients participating in a placebo controlled trial of interferon beta-1a, as indexed both by clinical exacerbation rate and by the number and volume of gadolinium-diethylenetriaminepentaacetic acid (Gd-DTPA) enhancing lesions on MRI. "At risk" periods were defined around symptomatic URTI, with or without serological confirmation.

RESULTS

The relative risk of clinical relapse for serologically unconfirmed symptomatic URTI was 2.1 (p=0.004). Raised antiviral antibody titres conferred a relative risk of multiple sclerosis exacerbations that was 3.4 times higher than the "not at risk" periods (annual attack rates of 5.7 v 1.6, respectively, p=0.006). There was no definite relation between the number or the volume of active lesions on MRI and either symptomatic or serologically defined at risk periods.

CONCLUSIONS

These results confirm the previously reported association between viral infections and multiple sclerosis exacerbations and indicate that the relative risk may be even higher when viral infection is serologically confirmed. However, the results, perhaps because of the confounding effects of interferon beta-1a, do not provide convincing evidence of increased blood-brain barrier breakdown or inflammation during periods of virally induced immune stimulation.

Antibodies against endothelial cells in patients with multiple sclerosis

OBJECTIVES

The humoral immune response seems to play a role in the pathogenesis of multiple sclerosis (MS). The blood-brain-barrier (BBB) and particularly the endothelial cell may be a possible target for this immune response.

MATERIAL & METHODS

using an ELISA technique, we have investigated the prevalence of antibodies directed against human vein endothelial cells in the sera of 84 patients with MS, 35 stroke patients, 50 systemic lupus erythematosus (SLE) and 76 normal controls. The measurements in MS patients were tested a second time after cytokine stimulation with gamma and beta-interferon at different doses. Seven MS patients (two positive and five negative) had three or more clinical assessments including the Expanded Disability Status Scale (EDSS) over a three-month period, and at least three AECA determinations were carried out. Gadolinium MRI examinations were performed monthly during these three months.

RESULTS

Anti-endothelial cell antibodies (AECA) have been identified in 9 of 84 patients suffering from MS (10.71%), in 3 of 35 stroke patients (8.57%) and in 20 of 50 SLE patients (40%). None of 76 normal controls had a positive titre of AECA. Cytokine stimulations did not modify the detection of these antibodies. No correlation between AECA and different clinical parameters such as onset age, clinical symptoms at onset and at sampling, clinical course and score measured by the EDSS was found in MS patients. No relationship was found between MRI activity and the presence of AECA.

CONCLUSION

AECA do not seem to be a marker for a specific subset of MS patients.

Is there a case for a virus aetiology in multiple sclerosis?

Multiple Sclerosis (MS) is a devastating demyelinating disease with a very high prevalence in North-East Scotland and in the Orkney and Shetland Islands. MS appears to be a multifactorial disorder with environmental and genetic elements and it has been proposed that these, in tandem, provoke an autoimmune response giving rise to the disease. Although there is no direct evidence of a specific virus being involved in MS, there are nevertheless grounds for suspecting a viral association. This review discusses these aspects of MS and suggests that a more aggressive approach to unravelling the role of viruses is needed.