Different responses to interferon beta-1b treatment in patients with neuromyelitis optica and multiple sclerosis

Testing for antibodies to human aquaporin-4 by ELISA: sensitivity, specificity, and direct comparison with immunohistochemistry

BACKGROUND

Several assays have been developed to detect antibodies to aquaporin-4 (NMO-IgG/AQP4-Ab). However, many of these assays require sophisticated techniques and are thus only available at specialized laboratories. This is problematic since NMO-IgG/AQP4-Ab testing has important prognostic and therapeutic implications.

OBJECTIVE

To evaluate a newly developed, commercial, enzyme-linked immunosorbent assay (ELISA) for detecting NMO-IgG/AQP4-Ab.

METHODS

Serum samples from 261 patients with NMO spectrum disorders (NMOSD; n=108) and controls (n=153) were tested for AQP4-Ab by using ELISA. Of these patients, 207 were tested in parallel using a standard immunohistochemical (IHC) assay.

RESULTS

Fifty of 66 (75.8%) patients with NMO, 17/25 (68%) with LETM, 3/14 (21.4%) with ON, 2/3 (66.7%) with ON and non-extensive transverse myelitis, and 2/153 (1.3%) controls tested positive in the ELISA. Of those NMOSD patients tested by both ELISA and IHC, 10 were positive only in the ELISA and 3 exclusively in the IHC assay, suggesting that the overall sensitivity of the ELISA was higher than that of the standard IHC assay. The ELISA yielded very good intra- and inter-run reproducibility with regard to AQP4-Ab detection and good intrarun, but only moderate inter-run reproducibility with regard to AQP4-Ab quantification. Anti-AQP4 serum concentrations correlated with disease activity (p<0.00001), but did not differ between patients with NMO and patients with isolated LETM or ON.

CONCLUSION

The ELISA evaluated here provides a relatively sensitive and easy-to-use diagnostic tool for detecting antibodies to AQP4 and could make AQP4-Ab testing, which is of high clinical relevance, more widely available.

Immunotherapies in neurologic disorders

Therapy for autoimmune demyelinating disorders has evolved rapidly over the past 10 years to include traditional immunosuppressants as well as novel biologicals. Antibody-mediated neuromuscular disorders are treated with therapies that acutely modulate pathogenic antibodies or chronically inhibit the humoral immune response. In other inflammatory autoimmune disorders of the peripheral and central nervous system, corticosteroids, often combined with conventional immunosuppression, and immunomodulatory treatments are used. Because autoimmune neurologic disorders are so diverse, evidence from randomized controlled trials is limited for most of the immunotherapies used in neurology. This review provides an overview of the immunotherapies currently used for neurologic disorders.

Type I interferons as ambiguous modulators of chronic inflammation in the central nervous system

Type I interferons (IFNs) were originally identified as antiviral effector molecules that exert pleiotropic physiological processes ranging from immune modulation, control of proliferation, apoptosis to antitumor activity. However, type I IFNs were recently also shown to apply both beneficial and detrimental effects to the central nervous system (CNS) and a tightly balanced equilibrium between cellular activation and inhibition seems to be essential to maintain homeostasis within the CNS. In inflammatory pathologies affecting the CNS, type I IFNs are in the center of attention not only because interferon beta (IFN-β) is used as a standard therapeutic in the treatment of relapsing–remitting multiple sclerosis (MS), but also as type I IFN expression is associated with distinct pathologies. Despite the great efficiency of IFN-β in reducing MS relapses and attenuation of novel inflammatory lesions is well documented, underlying molecular mechanisms and cellular target specificities are just beginning to emerge. In contrast to the curative effects, aberrant activation of the type I IFN response were also recently shown to be associated with detrimental effects exemplified by the Aicardi–Goutières syndrome (AGS), a severe disabling autoimmune inflammatory encephalopathy. This review will highlight the dual role of type I interferons during chronic CNS inflammation. Recently uncovered molecular and cellular mechanisms in the etiology of AGS and experimental autoimmune encephalomyelitis (EAE), the murine model of MS will be highlighted.

Does interferon beta treatment exacerbate neuromyelitis optica spectrum disorder?

Objectives:

Recent case reports and series have shown that patients with neuromyelitis optica (NMO) experience clinical deterioration under interferon beta (IFN-β) treatment. The objective of the present study was to evaluate whether and to what extent IFN-β exacerbates NMO spectrum disorders (NMOSD).

Methods:

We retrospectively reviewed the medical records of 40 patients with NMOSD who had been treated with IFN-β for more than 6 months and whose disease duration was more than 1 year at the initiation of IFN-β treatment. We evaluated their annualized relapse rates (ARR) and Expanded Disability Status Scale (EDSS) scores before and after IFN-β treatment.

Results:

In total, 95% of patients exhibited an ineffective or exacerbated response to IFN-β treatment and the mean ARR significantly increased after IFN-β treatment ( p = 0.002). The increased ARR > 50% under IFN-β treatment was observed in 20 patients (50%). The mean EDSS score significantly increased following IFN-β treatment ( p < 0.001).

Conclusion:

In patients with NMOSD, IFN-β treatment is not only ineffective for preventing relapses but also may even increase relapses significantly. Thus, a more careful diagnostic approach to differentiate NMO from multiple sclerosis and attention to decision of treatment is warranted for patients at high risk of NMO.

Protective effect of an elastase inhibitor in a neuromyelitis optica-like disease driven by a peptide of myelin oligodendroglial glycoprotein

BACKGROUND

The pathology of neuromyelitis optica (NMO), in contrast to multiple sclerosis, comprises granulocyte infiltrates along extensive lengths of spinal cord, as well as optic nerve. Furthermore, IFN-β treatment worsens NMO. We recently found that experimental autoimmune encephalomyelitis (EAE) induced with Th17 cells is exacerbated by IFN-β, in contrast to disease induced with Th1 where treatment attenuated symptoms.

OBJECTIVE

This study demonstrates the similarities between NMO and Th17 EAE and how neutrophils mediate pathology in Th17 disease.

METHODS

Levels of blood biomarkers in NMO were assessed by Luminex and ELISA. Effects of IFN-β on neutrophils were assessed by culture assays and immunofluorescence. EAE was induced by transfer of myelin-specific Th1 or Th17 cells and treated with Sivelestat sodium hydrate, a neutrophil elastase inhibitor.

RESULTS

We show Th17 cytokines, granulocyte chemokines, type 1 interferon and neutrophil elastase are elevated in patients with definitive NMO. In culture, we find that IFN-β stimulates neutrophils to release neutrophil elastase. In Th17 EAE, we demonstrate neutrophilic infiltration in the optic nerve and spinal cord which was not present in Th1 EAE. Blockade of neutrophil elastase with Sivelestat had efficacy in Th17 EAE but not Th1 EAE.

CONCLUSIONS

The similarities between Th17 EAE and NMO indicate that this model represents several aspects of NMO. Neutrophils are critical in the pathologies of both Th17-EAE and NMO, and therefore blockade of neutrophil elastase is a promising target in treating NMO.

Neuromyelitis optica: an antibody-mediated disorder of the central nervous system

Neuromyelitis optica (NMO) is a recurrent inflammatory disease that preferentially targets the optic nerves and spinal cord leading to blindness and paralysis. The hallmarks of NMO include bilateral optic neuritis and longitudinally extensive transverse myelitis. Woman and African Americans are overrepresented in the US patient population. NMO is associated with the NMO-IgG biomarker, which targets the aquaporin-4 water channel on astrocytes. The humoral pathology of NMO lesions include IgG and IgM deposits and infiltration by granulocytes suggesting that the NMO-IgG may be involved in the pathogenesis of disease. This review of the recent NMO literature covers the clinical features, epidemiology, radiology and pathology of disease and includes discussion of the important basic science research work in the field.

Contrasting disease patterns in seropositive and seronegative neuromyelitis optica: A multicentre study of 175 patients

Background

The diagnostic and pathophysiological relevance of antibodies to aquaporin-4 (AQP4-Ab) in patients with neuromyelitis optica spectrum disorders (NMOSD) has been intensively studied. However, little is known so far about the clinical impact of AQP4-Ab seropositivity.

Objective

To analyse systematically the clinical and paraclinical features associated with NMO spectrum disorders in Caucasians in a stratified fashion according to the patients' AQP4-Ab serostatus.

Methods

Retrospective study of 175 Caucasian patients (AQP4-Ab positive in 78.3%).

Results

Seropositive patients were found to be predominantly female (p < 0.0003), to more often have signs of co-existing autoimmunity (p < 0.00001), and to experience more severe clinical attacks. A visual acuity of ≤ 0.1 during acute optic neuritis (ON) attacks was more frequent among seropositives (p < 0.002). Similarly, motor symptoms were more common in seropositive patients, the median Medical Research Council scale (MRC) grade worse, and MRC grades ≤ 2 more frequent, in particular if patients met the 2006 revised criteria (p < 0.005, p < 0.006 and p < 0.01, respectively), the total spinal cord lesion load was higher (p < 0.006), and lesions ≥ 6 vertebral segments as well as entire spinal cord involvement more frequent (p < 0.003 and p < 0.043). By contrast, bilateral ON at onset was more common in seronegatives (p < 0.007), as was simultaneous ON and myelitis (p < 0.001); accordingly, the time to diagnosis of NMO was shorter in the seronegative group (p < 0.029). The course of disease was more often monophasic in seronegatives (p < 0.008). Seropositives and seronegatives did not differ significantly with regard to age at onset, time to relapse, annualized relapse rates, outcome from relapse (complete, partial, no recovery), annualized EDSS increase, mortality rate, supratentorial brain lesions, brainstem lesions, history of carcinoma, frequency of preceding infections, oligoclonal bands, or CSF pleocytosis. Both the time to relapse and the time to diagnosis was longer if the disease started with ON (p < 0.002 and p < 0.013). Motor symptoms or tetraparesis at first myelitis and > 1 myelitis attacks in the first year were identified as possible predictors of a worse outcome.

Conclusion

This study provides an overview of the clinical and paraclinical features of NMOSD in Caucasians and demonstrates a number of distinct disease characteristics in seropositive and seronegative patients.

New-onset type 1 diabetes mellitus and anti-aquaporin-4 antibody positive optic neuritis associated with type 1 interferon therapy for chronic hepatitis C

A 60-year-old woman developed type 1 diabetes mellitus and anti-aquaporin-4 antibody positive optic neuritis during type 1 interferon therapies for chronic hepatitis C. The diabetes mellitus was elicited by interferon-α plus ribavirin therapy, while the optic neuritis was induced after interferon-β treatment, followed by interferon-α and ribavirin therapy. It is possible that type 1 interferons lead to the onset of the two autoimmune diseases by inducing disease-specific autoantibodies. Autoimmune disease is an infrequent complication of type 1 interferon treatment; however, once it has occurred, it may result in severe impairments. Patients undergoing type 1 interferon therapy should therefore be carefully monitored for any manifestations of autoimmune diseases.

Treatment of neuromyelitis optica: an evidence based review

Neuromyelitis optica (NMO) is an inflammatory disease of the central nervous system characterized by severe optic neuritis and transverse myelitis, usually with a relapsing course. Aquaporin-4 antibody is positive in a high percentage of NMO patients and it is directed against this water channel richly expressed on foot processes of astrocytes. Due to the severity of NMO attacks and the high risk for disability, treatment should be instituted as soon as the diagnosis is confirmed. There is increasing evidence that NMO patients respond differently from patients with multiple sclerosis (MS), and, therefore, treatments for MS may not be suitable for NMO. Acute NMO attacks usually are treated with high dose intravenous corticosteroid pulse and plasmapheresis. Maintenance therapy is also required to avoid further attacks and it is based on low-dose oral corticosteroids and non-specific immunosuppressant drugs, like azathioprine and mycophenolate mofetil. New therapy strategies using monoclonal antibodies like rituximab have been tested in NMO, with positive results in open label studies. However, there is no controlled randomized trial to confirm the safety and efficacy for the drugs currently used in NMO.

Type I interferon signature is high in lupus and neuromyelitis optica but low in multiple sclerosis

OBJECTIVE

Neuromyelitis optica (NMO) is characterized by selective inflammation of the spinal cord and optic nerves but is distinct from multiple sclerosis (MS). Interferon (IFN)-β mitigates disease activity in MS, but is controversial in NMO, with a few reports of disease worsening after IFN-β therapy in this highly active disease. In systemic lupus erythematosus (SLE), IFNs adversely affect disease activity. This study examines for the first time whether serum IFN-α/β activity and IFN-β-induced responses in peripheral blood mononuclear cells (MNC) are abnormally elevated in NMO, as they are in SLE, but contrast to low levels in MS.

METHODS

Serum type I IFN-α/β activity was measured by a previously validated bioassay of 3 IFN-stimulated genes (RT-PCR sensitivity, 0.1 U/ml) rather than ELISA, which has lower sensitivity and specificity for measuring serum IFNs. IFN responses in PBMNC were assessed by in vitro IFN-β-induced activation of phospho-tyrosine-STAT1 and phospho-serine-STAT1 transcription factors, and MxA proteins using Western blots.

RESULTS

Serum IFN-α/β activity was highest in SLE patients, followed by healthy subjects and NMO, but was surprisingly low in therapy-naïve MS. In functional assays in vitro, IFN-β-induced high levels of P-S-STAT1 in NMO and SLE, but not in MS and controls. IFN-β-induced MxA protein levels were elevated in NMO and SLE compared to MS.

CONCLUSIONS

Serum IFN activity and IFN-β-induced responses in PBMNC are elevated in SLE and NMO patients versus MS. This argues for similarities in pathophysiology between NMO and SLE and provides an explanation for IFN-induced disease worsening in NMO.

Current and future treatment approaches for neuromyelitis optica

Neuromyelitis optica (NMO) is an inflammatory disease of the central nervous system (CNS) characterized by severe attacks of optic neuritis and myelitis, and which, unlike multiple sclerosis (MS), commonly spares the brain in the early stages. NMO used to be considered as a special form of MS. During the past 10 years, however, the two diseases have been shown to be clearly different. NMO is a B-cell-mediated disease associated with anti-aquaporin-4 antibodies in many cases and its pathophysiology seems to be near the acute lesion of necrotizing vasculitis. Assessment of prevalence shows that NMO is far less frequent than MS, which explains the absence of randomized clinical trials and NMO treatment strategies validated by evidence-based medicine. Recently, many data have been published that suggest that the therapeutic option in NMO should be immunosuppressive rather than immunomodulatory drugs. In the present study, after a brief overview of NMO, we review therapeutic studies and propose new therapeutic strategies in the relapse and disease-modifying fields.

Relapse of neuromyelitis optica spectrum disorder associated with intravenous lidocaine

Lidocaine unmasks silent symptoms and eases neuropathic pain in multiple sclerosis patients; however, the effects of lidocaine in neuromyelitis optica have never been reported. We describe the case of a 59-year-old Japanese woman with neuromyelitis optica spectrum disorder who developed optic neuritis 1 day after intravenous lidocaine injection for treating allodynia. Her symptom seemed to result from a relapse of neuromyelitis optica induced by lidocaine administration, and not because of the transient effects of intravenous lidocaine administration. The possibility that lidocaine administration results in relapse of neuromyelitis optica due to its immunomodulating effects cannot be ruled out.

Interferon-β exacerbates Th17-mediated inflammatory disease

Interferon (IFN)-β is the treatment most often prescribed for relapsing-remitting multiple sclerosis (RRMS). 30-50% of MS patients, however, do not respond to IFN-β. In some cases, IFN-β exacerbates MS, and it consistently worsens neuromyelitis optica (NMO). To eliminate unnecessary treatment for patients who are non-responsive to IFN-β, and to avoid possible harm, researchers are identifying biomarkers that predict treatment outcome before treatment is initiated. These biomarkers reveal insights into the mechanisms of disease. Recent discoveries on human samples from patients with RRMS, NMO, psoriasis, rheumatoid arthritis, systemic lupus erythematosus and ulcerative colitis, indicate that IFN-β is ineffective and might worsen clinical status in diverse diseases when a Th17 immune response is prominent.

Managing relapsing–remitting multiple sclerosis following first drug failure

SUMMARY IFN-β and glatiramer acetate are the usual first-line treatments for cases of relapsing–remitting multiple sclerosis. As both of these agents are only partially effective in controlling disease activity, ‘breakthrough’ disease is common. Deciding how much breakthrough constitutes a treatment failure necessitating a switch in therapy is now a common problem that most clinicians will encounter in practice. In this article we will discuss the approach to deciding when treatment failure occurs and the strategies that can be used to tackle this problem.

Expression of chemokine receptors on peripheral blood lymphocytes in multiple sclerosis and neuromyelitis optica

Background

The role of different chemokine receptors in the pathogenesis of multiple sclerosis (MS) has been extensively investigated; however, little is known about the difference in the role of chemokine receptors between the pathogenesis of neuromyelitis optica (NMO) and MS. Therefore, we examined the expression of chemokine receptors on peripheral blood lymphocytes (PBL) in MS and NMO.

Methods

We used flow cytometry to analyse lymphocyte subsets in 12 patients with relapsing NMO, 24 with relapsing-remitting MS during relapse, 3 with NMO and 5 with MS during remission.

Results

Compared with healthy controls (HC), the percentage of lymphocytes in white blood cells was significantly lower in NMO and MS patients. The percentage of T cells expressing CD4⁺CD25⁺ and CD4⁺CD45RO⁺ was higher, while that of CD4⁺CC chemokine receptor (CCR)3⁺ (T helper 2, Th2) was significantly lower in MS patients than in HC. The ratios of CD4⁺CXC chemokine receptors (CXCR)3⁺/CD4⁺CCR3⁺ (Th1/Th2) and CD8⁺CXCR3⁺/CD8⁺CCR4⁺ (T cytotoxic 1, Tc1/Tc2) were higher in MS patients than in HC. The percentage of CD8⁺CXCR3⁺ T cell (Tc1) and CD4⁺CXCR3⁺ T cell (Th1) decreased significantly during remission in MS patients (P <0.05). No significant differences were identified in the expression of the chemokine receptors on PBL in NMO patients compared with MS patients and HC.

Conclusions

Th1 dominance of chemokine receptors on blood T cells and the correlation between CXCR3⁺ T cell (Th1 and Tc1) and disease activity in MS patients were confirmed by analysing chemokines receptors on PBL. In contrast, deviation in the Th1/Th2 balance was not observed in NMO patients.

Cytokine and chemokine profiles in neuromyelitis optica: significance of interleukin-6

BACKGROUND

Neuromyelitis optica (NMO) is assumed to be immunologically distinct from multiple sclerosis (MS). Adequate studies about cytokines and chemokines in NMO have been lacking.

OBJECTIVE

To investigate the contribution of cytokines/chemokines in the pathogenesis of NMO.

METHODS

We measured 27 cytokines/chemokines and Th17 cell-associated cytokines in the cerebrospinal fluid (CSF) of 31 NMO, 29 MS and 18 other non-inflammatory neurological disorders patients. The serum levels of some cytokines/ chemokines were also measured. The correlations between clinical characteristics/laboratory findings and levels of cytokines/chemokines in NMO were examined.

RESULTS

The CSF levels of interleukin (IL)-1 receptor antagonist, IL-6, IL-8, IL-13 and granulocyte colony-stimulating factor were significantly increased in NMO, while IL-9, fibroblast growth factor-basic, granulocyte macrophage colony-stimulating factor, macrophage inflammatory protein-1-beta and tumor necrosis factor-alpha were increased in MS. IL-10 and interferon-gamma-inducible protein-10 were elevated in NMO and MS. In serum analyses, only the IL-6 level showed significant elevation in NMO. The CSF IL-6 level had a significant correlation with the CSF glial fibrillary acidic protein level and CSF cells, and a weak correlation with anti-aquaporin-4 antibody titers.

CONCLUSIONS

Different immunological status and pathophysiologies exist between NMO and MS, and IL-6 may play important roles in the pathogenesis of NMO.

Multiple sclerosis pharmacogenetics: personalized approach towards tailored therapeutics

Multiple sclerosis (MS) is a chronic autoimmune disease, where T-cells attack the myelin sheath in the central nervous system (CNS), characterized by relapsing-remitting episodes, or gradually increasing severity of symptoms and disability that accumulate over time. While current MS therapies have been proven in clinical trials to provide significant benefits, they cater only to subsets of patients. Moreover, there is an acute need to identify the most effective and safe treatment appropriate for each patient prospectively, since early intervention has been proven to prevent accumulation of irreversible dysfunction. In this review we discuss the current state-of-the-art in pharmacogenetic research as applied to the common marketed and in-development MS treatments, with respect to both efficacy and safety aspects. We conclude by discussing the relevance of pharmacogenetics and other biomarkers to the prediction, prevention and personalization of MS medications in the horizon.