Persistency of neutralizing antibodies depends on titer and interferon-beta preparation.

BACKGROUND: Neutralizing antibodies (NAbs) affect the efficacy of interferon-beta (IFNß) treatment in multiple sclerosis (MS) patients, particularly if NAbs persist. Persistency depends on NAb titers, which differ between IFNß preparations. OBJECTIVE: This study evaluated IFNß preparation-specific NAb cut-off titers during early treatment for prediction of NAb persistency. METHODS: Patients who had at least one NAb test between 12 and 30 months (baseline) as well as after more than 48 months (follow-up) on IFNß treatment were included in this longitudinal study. RESULTS: At baseline 1064 patients had a NAb test. Of those, 203 had a follow-up test. In the follow-up group 23.2% of patients were NAb positive during baseline. NAb frequency significantly decreased by 40.7% in the IFNß-1a and by 60% in the IFNß-1b group at follow-up after a mean time of 75.4 months on treatment, and median NAb titers decreased significantly in both groups. During baseline, NAb titers of >258 neutralizing units (NU) had a sensitivity of 81.3% and a specificity of 90.9% in the IFNß-1a group, whereas titers of >460 NU had a sensitivity of 100% and a specificity of 91.7% in the IFNß-1b group to predict persistency at follow-up. When these cut-off titers are applied, 10.2% of all treated patients developed persistent NAbs. CONCLUSION: IFNß preparation-specific NAb cut-off titers for prediction of NAb persistency, which may be useful in individual treatment decision making, are provided.

Influence of interferon-beta therapy switching on neutralizing antibody titres: results from the Austrian Switch Study.

Neutralizing antibodies against interferon-beta are associated with a reduction of the efficacy of this drug. Continuing treatment leads to a decline or even loss of neutralizing antibodies over years. No strategies are currently available to shorten the period of neutralizing antibody positivity. The objective of this study was to investigate the effect of switching between high and low immunogenic interferon-beta products on neutralising antibody titres. Twenty-four patients treated with the subcutaneously administered interferon-beta 1b or 1a and high titres of neutralizing antibodies were included. At baseline interferon-beta therapy was interrupted for 3 months and two pulses of high dose methylprednisolone were applied. Patients were then randomized to receive either the previous interferon-beta preparation or the low immunogenic intramuscular interferon-beta 1a. The primary end-point was the change of neutralizing antibody titres 12 months after randomization. Twelve patients were switched to interferon-beta 1a intramuscularly and 12 patients remained on previous treatment. Median neutralizing antibody titres were 846 NU at baseline and 196 NU at the end of the study. The median change of neutralizing antibody titres did not differ significantly between therapy switchers and non-switchers. Baseline and final neutralizing antibody titres correlated significantly. In conclusion, neither switching nor continuous therapy with any subcutaneous interferon-beta preparation significantly changed neutralizing antibody titres.

Epitope specificity of serum antibodies directed against the extracellular domain of myelin oligodendrocyte glycoprotein: Influence of relapses and immunomodulatory treatments.

Only few reports are available on the epitope specificity of anti-myelin oligodendrocyte glycoprotein (MOG) antibodies in multiple sclerosis (MS). In the present study we provide a precise characterization of the epitope specificity of serum antibodies directed against the extracellular domain of MOG, including IgG, IgM and IgA immunoglobulin isotypes in 28 relapsing remitting MS patients and report that linear epitopes amino-acid (aa) 37-48 and aa42-53 are immunodominant. Recently experienced relapses intensified the anti-MOG peptide antibody response. Immunomodulatory treatment with interferon-beta or glatiramer-acetate had no major impact on the anti-MOG peptide immunoreactivity after 1 year of therapy.

Increased serum levels of soluble CD14 indicate stable multiple sclerosis.

The aim of this study was to evaluate a possible role of soluble CD14 (sCD14) in multiple sclerosis (MS). We found that sCD14 serum levels measured by ELISA were higher in MS patients compared to neurological and healthy controls. Within the MS group sCD14 levels were increased in relapsing-remitting and secondary progressive MS compared to primary progressive MS. Furthermore, sCD14 concentrations were increased during stable disease. An increased expression of sCD14 was also detected after treatment with interferon-beta. In summary, we report evidence that serum sCD14 levels are increased in MS and correlate inversely with disease activity in relapsing MS patients.

Plasma levels of soluble adhesion molecules sPECAM-1, sP-selectin and sE-selectin are associated with relapsing-remitting disease course of multiple sclerosis.

Adhesion molecule mediated leukocyte migration into the central nervous system is considered to be a critical step in the pathogenesis of multiple sclerosis (MS). We measured plasma levels of the soluble adhesion molecules sPECAM-1, sP-selectin and sE-selectin in 166 MS patients and in 36 healthy blood donors with ELISA. sPECAM-1, sP-selectin and sE-selectin plasma concentrations showed a significant increase in the relapsing-remitting disease course of MS and were elevated during relapse. These findings indicate that sPECAM-1, sP-selectin and sE-selectin might be implemented as paraclinical markers of disease activity in MS with restriction to the clinical course of the disease.

Epitope specificity of neutralizing antibodies against IFN-beta.

Neutralizing antibodies (NAb), a subset of antibodies against interferon-beta (IFN-beta) that inhibit activation of the IFN-beta receptor, are presumed to bind to the receptor-binding site of IFN-beta. The aim of this study was to identify specific epitopes for human NAb and nonneutralizing antibodies (NNAb) on the IFN-beta molecule. Thirty-one 12-mer peptides and one 11-mer peptide representing the amino acid sequence of the human IFN-beta molecule were used as antigens in an ELISA antibody assay. Significant antibody binding was observed at residues 1-12, 121-132, and 151-162. NNAb and NAb recognized residues 121-132 with equal frequency, but NAb had higher titers. NAb bound significantly more frequently to residues 1-12 and 151-162. There was a significant positive correlation between NAb titers and titers against residues 1-12. Binding to residues 1-12 was more pronounced in patients treated with IFN-beta1a than in patients treated with IFN-beta1b. Our results indicate a qualitative and quantitative difference between NAb and NNAb, with special emphasis on the recognition of different epitopes.

Fibrinogen is not elevated in the cerebrospinal fluid of patients with multiple sclerosis.

BACKGROUND: Elevated plasma fibrinogen levels are a well known finding in acute infectious diseases, acute stroke and myocardial infarction. However its role in the cerebrospinal fluid (CSF) of acute and chronic central (CNS) and peripheral nervous system (PNS) diseases is unclear. FINDINGS: We analyzed CSF and plasma fibrinogen levels together with routine parameters in patients with multiple sclerosis (MS), acute inflammatory diseases of the CNS (bacterial and viral meningoencephalitis, BM and VM) and PNS (Guillain-Barré syndrome; GBS), as well as in non-inflammatory neurological controls (OND) in a total of 103 patients. Additionally, MS patients underwent cerebral MRI scans at time of lumbar puncture.CSF and plasma fibrinogen levels were significantly lower in patients with MS and OND patients as compared to patients with BM, VM and GBS. There was a close correlation between fibrinogen levels and albumin quotient (rho = 0.769, p < 0.001) which strongly suggests passive transfer of fibrinogen through the blood-CSF-barrier during acute inflammation. Hence, in MS, the prototype of chronic neuroinflammation, CSF fibrinogen levels were not elevated and could not be correlated to clinical and neuroradiological outcome parameters. CONCLUSIONS: Although previous work has shown clear evidence of the involvement of fibrinogen in MS pathogenesis, this is not accompanied by increased fibrinogen in the CSF compartment.

Natalizumab treatment reduces endothelial activity in MS patients.

Vascular cell adhesion molecule-1 a ligand for leukocyte very late activating antigen-4 is a key player in leukocyte extravasation in MS lesions. Natalizumab a monoclonal antibody against VLA-4 blocks this interaction. VCAM-1 and its soluble form are up-regulated during endothelial activation in MS. We investigated the effect of Natalizumab on sVCAM-1 and VLA-4 on circulating leukocytes in MS patients. Natalizumab reduced levels of sVCAM-1 compared to controls (256 vs. 597 ng/mL). This effect was sustained and only reversed in patients with neutralizing antibodies against Natalizumab. Correspondingly Natalizumab diminished VLA-4 on leukocyte subsets. Our findings indicate that Natalizumab reduces transmigration not only by blocking VLA-4 but also by down-regulating VCAM-1.

Features of intrathecal immunoglobulins in patients with multiple sclerosis.

We have analyzed immunoglobulin (Ig) isotypes and IgG subclasses in cerebrospinal fluid (CSF) and serum of patients with multiple sclerosis (MS) and other neurological diseases to determine whether different Ig isotype patterns correlate with clinical or paraclinical findings and CSF B cell populations. Intrathecal IgG1 synthesis was elevated in MS patients. An increased intrathecal IgM production was found in patients with a higher cerebral MRI lesion burden, whereas other clinical and paraclinical parameters were not associated with a specific Ig isotype or subclass profile. Finally, intrathecal IgG production (IgG1 and IgG3) correlated with the presence of mature B cells and plasma blasts.

Cerebrospinal fluid B cells correlate with early brain inflammation in multiple sclerosis.

BACKGROUND: There is accumulating evidence from immunological, pathological and therapeutic studies that B cells are key components in the pathophysiology of multiple sclerosis (MS). METHODOLOGY/PRINCIPAL FINDINGS: In this prospective study we have for the first time investigated the differences in the inflammatory response between relapsing and progressive MS by comparing cerebrospinal fluid (CSF) cell profiles from patients at the onset of the disease (clinically isolated syndrome, CIS), relapsing-remitting (RR) and chronic progressive (CP) MS by flow cytometry. As controls we have used patients with other neurological diseases. We have found a statistically significant accumulation of CSF mature B cells (CD19+CD138-) and plasma blasts (CD19+CD138+) in CIS and RRMS. Both B cell populations were, however, not significantly increased in CPMS. Further, this accumulation of B cells correlated with acute brain inflammation measured by magnetic resonance imaging and with inflammatory CSF parameters such as the number of CSF leukocytes, intrathecal immunoglobulin M and G synthesis and intrathecal production of matrix metalloproteinase (MMP)-9 and the B cell chemokine CxCL-13. CONCLUSIONS: Our data support an important role of CSF B cells in acute brain inflammation in CIS and RRMS.