Robert Egg

Anti-MOG and anti-MBP antibody subclasses in multiple sclerosis

In a subset of multiple sclerosis (MS) patients antibodies against myelin antigens seem to be important in the demyelinating process. In this study we investigated IgM, IgA and IgG serum antibodies against the myelin oligodendrocyte glycoprotein (MOG) and the myelin basic protein (MBP) in 261 MS patients. Seventy-two per cent had anti-MOG antibodies, 59% were anti-MBP seropositive. The dominating antibody was anti-MOG IgM. A significant relationship between IgA and a progressive disease course was found. The predominance of IgG1 together with the significantly associated occurrence of IgG3 against MOG corresponds to the prevailing IgG1 and IgG3 isotypes in other autoimmune diseases. Patients who actually suffered from a relapse were significant more often anti-MOG and anti-MBP IgG3 seropositive than those in remission. However, patients treated either with intravenous immunoglobulins or interferon-b showed a significant reduction of anti-MOG IgG3 antibodies.

Interferon-beta: the neutralizing antibody (NAb) titre predicts reversion to NAb negativity

Background: It has been reported that in some patients with MS who develop neutralizing antibodies (NAbs) against interferon beta (IFNb), antibody levels can initially increase and then decrease thereafter even when treatment is continued. Objective: To determine whether NAb titre correlates with time to reversion to NAb negativity in patients with multiple sclerosis (MS). Methods: Twenty-eight patients with MS who were NAb-positive during treatment with one of the currently available IFNbs were included in this retrospective study. NAb titres were determined by the myxovirus resistance protein A induction assay. Patients were considered NAb-positive if they had at least two consecutive samples with titres of]/20 neutralizing units (NU). Reversion to NAb-negative status was defined as two consecutive negative samples (NAb titre of B/20 NU) after NAb positivity. Results: When measured two years after treatment initiation, a NAb titre of B/75 NU had a 91.7% sensitivity and a 87.5% specificity for reversion to NAb negativity in the following two years (after a total of four years of treatment). In addition, somewhat surprisingly, patients whose serum converted to NAb-negative generally developed peak NAb titres earlier than patients who remained NAb-positive (mean time of first detection was 21 versus 38 months, respectively). Conclusion: The NAb titre might support treatment decisions in patients with MS whose test results are positive for NAbs.

Differing immunogenic potentials of interferon beta preparations in multiple sclerosis patients

Interferon beta (IFNβ) is a first-line therapy for multiple sclerosis (MS). However, some patients experience a decline in efficacy with continued therapy due to the development of anti-IFNβ neutralizing antibodies (NAb). We investigated the frequency of NAb cross-sectionally in 846 MS patients who were receiving IFNβ-1b, IFNβ-1a im, or IFNβ-1a sc. The frequency of NAb in patients receiving IFNβ-1a im was lower (5%) than in patients treated with any other form of IFNβ (22-35%) (P < 0.0001). Binding antibodies (BAb) were measured in 808 patients. The frequency differed significantly between treatment groups, ranging from 45% (IFNβ-1a im) to 88% (IFNβ-1b). The proportion of NAb-positive patients within the BAb-positive group differed significantly among treatment groups, ranging between 12% (IFNβ-1a im) and 51% (IFNβ-1a sc). The median NAb titer from all IFNβ-1a-treated patients was higher than from IFNβ-1b-treated patients (446 versus 171 NU/mL, P = 0.04). Among NAb-positive patients, the frequency of NAb titers > 100 NU/mL was 71% for IFNβ-1a compared with 58% for IFNβ-1b (P = 0.04). Except for conflicting data regarding IFNβ-1a sc, the results are generally consistent with the literature and together with the differing proportion of NAb-positive patients within the BAb-positive group, provide further insight into the immunogeni-city of the IFNβ preparations.

Epitope Specificity of Neutralizing Antibodies Against IFN-β

Neutralizing antibodies (NAb), a subset of antibodies against interferon-β (IFN-β) that inhibit activation of the IFN-β receptor, are presumed to bind to the receptor-binding site of IFN-β. The aim of this study was to identify specific epitopes for human NAb and nonneutralizing antibodies (NNAb) on the IFN-β molecule. Thirty-one 12-mer peptides and one 11-mer peptide representing the amino acid sequence of the human IFN-β 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-β1a than in patients treated with IFN-β1b. Our results indicate a qualitative and quantitative difference between NAb an...

Autonomic instability, as measured by pupillary unrest, is not associated with multiple sclerosis fatigue severity

Multiple sclerosis (MS) fatigue is one of the most common symptoms in MS, but its pathophysiology is still not understood. Sympathovagal imbalance was suggested as a reason for fatigue in chronic fatigue syndrome. We examined the role of an imbalance in the central autonomic nervous system (ANS) as a cause of MS fatigue in 51 MS patients and a control group of 22 healthy volunteers. Fatigue was assessed with the revised MS Fatigue Severity Scale (FSS) and the Modified Fatigue Impact Scale (MFIS). Depression was evaluated with the Beck Depression Inventory (BDI). Disintegration of the central ANS expressed by pupillary fatigue waves was measured with pupillography and documented in the pupillary unrest index (PUI). All subjects had less than five points on the seven-point Stanford Sleepiness Scale and were therefore not sleepy. MS patients had significant higher mean FSS scores (p =0.001) and mean MFIS scores (p =0.003) than our control group. Mean BDI scores were significant higher (p=0.001) in the MS group, but were in the lowest score range (0 -10 points) in both groups. Surprisingly, we found a statistically significant inverse correlation between PUI values and either FSS scores (p=0.001; r = −0.521) or MFIS scores (p =0.002; r = −0.423) in the MS group, but not in healthy participants. We therefore conclude that autonomic instability, as measured by pupillary unrest, is not associated with MS fatigue severity.

Interferon-β antibodies have a higher affinity in patients with neutralizing antibodies compared to patients with non-neutralizing antibodies

In this study, we investigated the affinity, determined by a relative affinity assay, using increasing concentrations of sodium-isothiocyanate to disrupt the antigen antibody binding of neutralizing and non-neutralizing antibodies against interferon-beta (IFNbeta)-1a and -1b in 73 serum samples of MS patients treated with IFNbeta-1a or -1b. Relative affinity values were significantly higher in NAB-positive compared to NAB-negative samples and in samples of IFNbeta-1a-treated patients compared to IFNbeta-1b. A significant positive correlation between relative affinity values and therapy duration indicates affinity maturation as another qualitative factor in IFNbeta neutralization.

A novel and rapid assay for the detection of neutralizing antibodies against interferon-beta:

There is evidence that neutralizing antibodies (NA B) have a negative influence on the clinical and magnetic resonance imaging effects of interferon-beta (IFNb) in multiple sclerosis (MS) patients. The current methods for NA B detectio n are restricted to specialized laboratories because they require a cell culture and sometimes a viral culture. Results are typically obtained after several weeks. Therefore, the development of a simple and rapid assay for the detectio n of NA B was sought. Whole blood samples from 28 NAB-positive patients and 110 NAB-negative patients (52 with IFNb and 58 without IFNb therapy) were incubated with IFNb 976 IU/mL for 24 hours. MxA protein levels-a specific marker of class 1 IFN bioactivity-were measured in paired samples with and without IFNb incubatio n and the difference in MxA levels was calculated. The mean increase of MxA levels after stimulation with IFNb in the NAB-positive group was 8 ng/mL (range 0-44 ng/mL) and in the NA B-negative group was 84 ng/mL (range 0-302 ng/mL). Using an increase of 22.5 ng/mL as cut-off, the specificity of the MxA stimulation assay was 81.2% and the sensitivity was 96.4%. The whole blood MxA stimulation assay is virtually as sensitive as the conventional NA B assay but somewhat less specific. However, this is outweighed by the procedural advantage of the assay, which is simpler, quicker and much less expensive.

Anti-MOG antibody responses in multiple sclerosis(1): Reliable testsystems provide reliable results

4 3 1 Phenotypic and Functional Properties of Transformed ~/~ T Ceil Lines and Clones from MS CSF and Blood R.A. Port. M.S. Freedman, Ottawa GeneraIHospital, Canada 4 3 4 Anti-MeG Antibody Responses in Multiple Sclerosis(I): Refiable Testsystems Provide Refiable Results M. geindl, R. Egg, E Deisenhamm er, University oflnnsbruek, Austria, C. Linington, Max-Planck-lnstitut For Psyehiatry, Martinsried, Germany, T. Berger, University of Ing~bruck, Austria