Assessment of oligoclonal bands in cerebrospinal fluid and serum of dogs with meningoencephalitis of unknown origin.

BACKGROUND: Meningoencephalitis of unknown origin (MUO) is an inflammatory disease of the canine central nervous system (CNS) that shares several features with multiple sclerosis (MS) in humans. In approximately 95% of MS patients, ≥ two immunoglobulin G (IgG) oligoclonal bands (OCBs) are detectable exclusively in the cerebrospinal fluid (CSF). HYPOTHESIS/OBJECTIVES: To investigate OCBs in CSF and serum in dogs affected by MUO, intervertebral disc disease (IVDD), idiopathic epilepsy (IE), intracranial neoplasia (IN), steroid-responsive meningitis-arteritis (SRMA), and diseases outside the CNS. We hypothesize that the highest prevalence of CSF-specific OCBs (≥ two OCBs uniquely in the CSF) would be found in dogs affected by MUO. ANIMALS: Client-owned dogs (n = 121) presented to the neurology service due to neurological deficits. METHODS: Prospective study. Measurement of IgG concentration in CSF and serum via a canine IgG ELISA kit. OCB detection via isoelectric focusing (IEF) and immunoblot. RESULTS: Presence of CSF-specific OCBs was significantly higher in dogs with MUO (57%) compared to 22% in IN, 6% in IE, 15% in SRMA, 13% in IVDD, and 0% in the non-CNS group (p < .001). Dogs with MUO were 9.9 times more likely to show CSF-specific OCBs than all other diseases together (95% confidence interval, 3.7-26.4; p < .001). CONCLUSIONS AND CLINICAL IMPORTANCE: MUO showed the highest prevalence of CSF-specific OCBs, indicating an inflammatory B cell response. Future studies are needed to evaluate the prevalence in the specific MUO subtypes and a possible similarity with human MS.

Vaccination with Designed Neopeptides Induces Intratumoral, Cross-reactive CD4+ T-cell Responses in Glioblastoma.

PURPOSE: The low mutational load of some cancers is considered one reason for the difficulty to develop effective tumor vaccines. To overcome this problem, we developed a strategy to design neopeptides through single amino acid mutations to enhance their immunogenicity. EXPERIMENTAL DESIGN: Exome and RNA sequencing as well as in silico HLA-binding predictions to autologous HLA molecules were used to identify candidate neopeptides. Subsequently, in silico HLA-anchor placements were used to deduce putative T-cell receptor (TCR) contacts of peptides. Single amino acids of TCR contacting residues were then mutated by amino acid replacements. Overall, 175 peptides were synthesized and sets of 25 each containing both peptides designed to bind to HLA class I and II molecules applied in the vaccination. Upon development of a tumor recurrence, the tumor-infiltrating lymphocytes (TIL) were characterized in detail both at the bulk and clonal level. RESULTS: The immune response of peripheral blood T cells to vaccine peptides, including natural peptides and designed neopeptides, gradually increased with repetitive vaccination, but remained low. In contrast, at the time of tumor recurrence, CD8+ TILs and CD4+ TILs responded to 45% and 100%, respectively, of the vaccine peptides. Furthermore, TIL-derived CD4+ T-cell clones showed strong responses and tumor cell lysis not only against the designed neopeptide but also against the unmutated natural peptides of the tumor. CONCLUSIONS: Turning tumor self-peptides into foreign antigens by introduction of designed mutations is a promising strategy to induce strong intratumoral CD4+ T-cell responses in a cold tumor like glioblastoma.

Benralizumab in eosinophilic granulomatosis with polyangiitis complicated by Staphylococcus aureus sepsis.

Eosinophilic Granulomatosis with Polyangiitis (EGPA) is an ANCA-associated small-vessels vasculitis characterized by hypereosinophilia and eosinophilic asthma. EGPA with life-threatening organ involvement, particularly cardiac and central nervous system (CNS), is a medical emergency requiring immediate immunosuppression. We describe a 58-year-old patient with a history of chronic rhinosinusitis and eosinophilic asthma, who presented with fever, hypereosinophilia and systemic inflammation. Diagnostic workup identified a cardiac mass, CNS vasculitis, CNS embolization and Staphylococcus aureus in blood cultures. Due to rapid normalization of blood cultures, the intracardiac mass was not considered as primarily infective. Active EGPA with cardiac and CNS involvement complicated by a secondary S. aureus sepsis was diagnosed. In order to not negatively impact antibacterial immunity in active EGPA, antibiotic therapy was combined with Benralizumab, which was well tolerated and EGPA resolved rapidly. Benralizumab could serve as a therapeutic option for eosinophil-mediated pathologies in severely ill patients where immunosuppressives are initially contraindicated.

HLA-DR15 Molecules Jointly Shape an Autoreactive T Cell Repertoire in Multiple Sclerosis.

The HLA-DR15 haplotype is the strongest genetic risk factor for multiple sclerosis (MS), but our understanding of how it contributes to MS is limited. Because autoreactive CD4+ T cells and B cells as antigen-presenting cells are involved in MS pathogenesis, we characterized the immunopeptidomes of the two HLA-DR15 allomorphs DR2a and DR2b of human primary B cells and monocytes, thymus, and MS brain tissue. Self-peptides from HLA-DR molecules, particularly from DR2a and DR2b themselves, are abundant on B cells and thymic antigen-presenting cells. Furthermore, we identified autoreactive CD4+ T cell clones that can cross-react with HLA-DR-derived self-peptides (HLA-DR-SPs), peptides from MS-associated foreign agents (Epstein-Barr virus and Akkermansia muciniphila), and autoantigens presented by DR2a and DR2b. Thus, both HLA-DR15 allomorphs jointly shape an autoreactive T cell repertoire by serving as antigen-presenting structures and epitope sources and by presenting the same foreign peptides and autoantigens to autoreactive CD4+ T cells in MS.

GDP-l-fucose synthase is a CD4+ T cell-specific autoantigen in DRB3*02:02 patients with multiple sclerosis.

Multiple sclerosis is an immune-mediated autoimmune disease of the central nervous system that develops in genetically susceptible individuals and likely requires environmental triggers. The autoantigens and molecular mimics triggering the autoimmune response in multiple sclerosis remain incompletely understood. By using a brain-infiltrating CD4+ T cell clone that is clonally expanded in multiple sclerosis brain lesions and a systematic approach for the identification of its target antigens, positional scanning peptide libraries in combination with biometrical analysis, we have identified guanosine diphosphate (GDP)-l-fucose synthase as an autoantigen that is recognized by cerebrospinal fluid-infiltrating CD4+ T cells from HLA-DRB3*-positive patients. Significant associations were found between reactivity to GDP-l-fucose synthase peptides and DRB3*02:02 expression, along with reactivity against an immunodominant myelin basic protein peptide. These results, coupled with the cross-recognition of homologous peptides from gut microbiota, suggest a possible role of this antigen as an inducer or driver of pathogenic autoimmune responses in multiple sclerosis.

Challenges and needs in experimental therapies for multiple sclerosis.

PURPOSE OF REVIEW: Despite dramatic advances in the treatment of people with multiple sclerosis over the last decade, several unmet medical needs still remain and should be approached with new compounds in experimental clinical trials. The prerequisites for successful clinical trials in multiple sclerosis have changed considerably over time and activities have started to improve clinical development of new drugs in several aspects including trial designs, patient selection and outcome parameters. This review will address some of the challenges in early experimental trials in multiple sclerosis and recent approaches in the field. RECENT FINDINGS: Highly intensive treatment regimens like autologous hematopoietic stem cell transplantation provide evidence for sustained long-term treatment effects in multiple sclerosis patients. Several different approaches towards neuroprotection and remyelination have entered the clinical phase and demonstrated that stabilization, even improvement of disability is achievable in short-term studies. SUMMARY: New therapeutic strategies have entered the clinic with the prospects of long-term efficacy and enduring effects on disability progression.

Restoring immune tolerance in neuromyelitis optica: Part I.

Neuromyelitis optica (NMO) and spectrum disorder (NMO/SD) represent a vexing process and its clinical variants appear to have at their pathogenic core the loss of immune tolerance to the aquaporin-4 water channel protein. This process results in a characteristic pattern of astrocyte dysfunction, loss, and demyelination that predominantly affects the spinal cord and optic nerves. Although several empirical therapies are currently used in the treatment of NMO/SD, none has been proven effective in prospective, adequately powered, randomized trials. Furthermore, most of the current therapies subject patients to long-term immunologic suppression that can cause serious infections and development of cancers. The following is the first of a 2-part description of several key immune mechanisms in NMO/SD that might be amenable to therapeutic restoration of immune tolerance. It is intended to provide a roadmap for how potential immune tolerance restorative techniques might be applied to patients with NMO/SD. This initial installment provides a background rationale underlying attempts at immune tolerization. It provides specific examples of innovative approaches that have emerged recently as a consequence of technical advances. In several autoimmune diseases, these strategies have been reduced to practice. Therefore, in theory, the identification of aquaporin-4 as the dominant autoantigen makes NMO/SD an ideal candidate for the development of tolerizing therapies or cures for this increasingly recognized disease.

Orbital Pseudotumor as a Rare Extrahepatic Manifestation of Hepatitis C Infection.

Hepatitis C is frequently accompanied by immune-related extrahepatic manifestations affecting the skin, kidneys, central and peripheral nervous system and exocrine glands. We present the case of a 40-year-old man with left-sided ptosis, exophthalmos and headache. MRI demonstrated left-sided orbital pseudotumor with lacrimal and retro-orbital contrast enhancement extending to the cavernous sinus and the vestibulocochlear nerve. Immunological tests of serum and cerebrospinal fluid identified hepatitis C virus (HCV) as a potential causative agent but did not indicate any additional infectious, malignant or immunological disorder. Hepatological evaluation revealed no signs of advanced liver disease. After initial spontaneous improvement, the patient subsequently developed vestibulocochlear failure with gait disorder, tinnitus and transient left-parietal sensory loss. Lacrimal biopsy demonstrated lymphocytic infiltrate, prompting steroid treatment. After initial improvement, steroids could not be tapered below 40 mg daily for several months due to recurrent symptoms. Twelve months after the initial presentation, the patient's chronic HCV infection was successfully treated with sofosbuvir, simeprevir and ribavirin and he remains now free of symptoms without steroids. In patients with chronic hepatitis C, lymphocytic infiltrate of the salivary and lacrimal glands is a frequent phenomenon. However, the extent of the lymphocytic infiltrate beyond the lacrimal gland to the tip of the orbit, cavernous sinus and vestibulocochlear nerve as in our patient is highly unusual. For all symptomatic extrahepatic manifestations of hepatitis C infection, treatment of HCV as the underlying immune stimulus is recommended, and it helped to control the symptoms in our patient. In addition, long-term follow-up for recurrent lymphocyte infiltrate and development of lymphoma is warranted.

Antigen-specific tolerance by autologous myelin peptide-coupled cells: a phase 1 trial in multiple sclerosis.

Multiple sclerosis (MS) is a devastating inflammatory disease of the brain and spinal cord that is thought to result from an autoimmune attack directed against antigens in the central nervous system. The aim of this first-in-man trial was to assess the feasibility, safety, and tolerability of a tolerization regimen in MS patients that uses a single infusion of autologous peripheral blood mononuclear cells chemically coupled with seven myelin peptides (MOG1-20, MOG35-55, MBP13-32, MBP83-99, MBP111-129, MBP146-170, and PLP139-154). An open-label, single-center, dose-escalation study was performed in seven relapsing-remitting and two secondary progressive MS patients who were off-treatment for standard therapies. All patients had to show T cell reactivity against at least one of the myelin peptides used in the trial. Neurological, magnetic resonance imaging, laboratory, and immunological examinations were performed to assess the safety, tolerability, and in vivo mechanisms of action of this regimen. Administration of antigen-coupled cells was feasible, had a favorable safety profile, and was well tolerated in MS patients. Patients receiving the higher doses (>1 × 10(9)) of peptide-coupled cells had a decrease in antigen-specific T cell responses after peptide-coupled cell therapy. In summary, this first-in-man clinical trial of autologous peptide-coupled cells in MS patients establishes the feasibility and indicates good tolerability and safety of this therapeutic approach.

Clinical and immunological follow-up of B-cell depleting therapy in CNS demyelinating diseases.

The aim of this observational study was to analyze clinical and immunological effects of rituximab treatment in neuromyelitis optica (NMO) and longitudinally extensive transverse myelitis (LETM) patients. We report on four NMO and two recurrent LETM patients who were treated with rituximab. Overall, B-cell depletion resulted in profound clinical stabilization in all patients. Rituximab did not affect titers of antibodies to aquaporin-4 (AQP4-IgG) and myelin oligodendrocyte glycoprotein, immunoglobulin (Ig) isotypes and IgG subtype distribution, even after long-term B-cell depletion. Relapses were not associated with re-emerging B-cells, serum levels of B-cell activating factor (BAFF) or AQP4-IgG titers. BAFF serum levels increased following rituximab treatment.

Complement activating antibodies to myelin oligodendrocyte glycoprotein in neuromyelitis optica and related disorders.

BACKGROUND: Serum autoantibodies against the water channel aquaporin-4 (AQP4) are important diagnostic biomarkers and pathogenic factors for neuromyelitis optica (NMO). However, AQP4-IgG are absent in 5-40% of all NMO patients and the target of the autoimmune response in these patients is unknown. Since recent studies indicate that autoimmune responses to myelin oligodendrocyte glycoprotein (MOG) can induce an NMO-like disease in experimental animal models, we speculate that MOG might be an autoantigen in AQP4-IgG seronegative NMO. Although high-titer autoantibodies to human native MOG were mainly detected in a subgroup of pediatric acute disseminated encephalomyelitis (ADEM) and multiple sclerosis (MS) patients, their role in NMO and High-risk NMO (HR-NMO; recurrent optic neuritis-rON or longitudinally extensive transverse myelitis-LETM) remains unresolved. RESULTS: We analyzed patients with definite NMO (n = 45), HR-NMO (n = 53), ADEM (n = 33), clinically isolated syndromes presenting with myelitis or optic neuritis (CIS, n = 32), MS (n = 71) and controls (n = 101; 24 other neurological diseases-OND, 27 systemic lupus erythematosus-SLE and 50 healthy subjects) for serum IgG to MOG and AQP4. Furthermore, we investigated whether these antibodies can mediate complement dependent cytotoxicity (CDC). AQP4-IgG was found in patients with NMO (n = 43, 96%), HR-NMO (n = 32, 60%) and in one CIS patient (3%), but was absent in ADEM, MS and controls. High-titer MOG-IgG was found in patients with ADEM (n = 14, 42%), NMO (n = 3, 7%), HR-NMO (n = 7, 13%, 5 rON and 2 LETM), CIS (n = 2, 6%), MS (n = 2, 3%) and controls (n = 3, 3%, two SLE and one OND). Two of the three MOG-IgG positive NMO patients and all seven MOG-IgG positive HR-NMO patients were negative for AQP4-IgG. Thus, MOG-IgG were found in both AQP4-IgG seronegative NMO patients and seven of 21 (33%) AQP4-IgG negative HR-NMO patients. Antibodies to MOG and AQP4 were predominantly of the IgG1 subtype, and were able to mediate CDC at high-titer levels. CONCLUSIONS: We could show for the first time that a subset of AQP4-IgG seronegative patients with NMO and HR-NMO exhibit a MOG-IgG mediated immune response, whereas MOG is not a target antigen in cases with an AQP4-directed humoral immune response.

EBNA1-specific T cells from patients with multiple sclerosis cross react with myelin antigens and co-produce IFN-gamma and IL-2.

Symptomatic primary Epstein-Barr virus (EBV) infection and elevated humoral immune responses to EBV are associated with an increased risk of developing multiple sclerosis (MS). We explored mechanisms leading to this change in EBV-specific immunity in untreated patients with MS and healthy virus carriers matched for MS-associated HLA alleles. MS patients showed selective increase of T cell responses to the EBV nuclear antigen 1 (EBNA1), the most consistently recognized EBV-derived CD4(+) T cell antigen in healthy virus carriers, but not to other EBV-encoded proteins. In contrast, influenza and human cytomegalovirus-specific immune control was unchanged in MS. The enhanced response to EBNA1 was mediated by an expanded reservoir of EBNA1-specific central memory CD4(+) T helper 1 (Th1) precursors and Th1 (but not Th17) polarized effector memory cells. In addition, EBNA1-specific T cells recognized myelin antigens more frequently than other autoantigens that are not associated with MS. Myelin cross-reactive T cells produced IFN-gamma, but differed from EBNA1-monospecific cells in their capability to produce interleukin-2, indicative of a polyfunctional phenotype as found in controlled chronic viral infections. Our data support the concept that clonally expanded EBNA1-specific CD4(+) T cells potentially contribute to the development of MS by cross-recognition of myelin antigens.

Getting specific: monoclonal antibodies in multiple sclerosis.

For more than a decade the only therapies that were available for multiple sclerosis (MS) were two immunomodulatory drugs-interferon beta and glatiramer acetate-and the immunosuppressant mitoxantrone. Natalizumab, a monoclonal antibody against alpha4 integrin, has been approved by the US Food and Drug Administration and the European Medicines Agency on the basis of its higher efficacy than the available treatments and its good safety profile. Monoclonal antibodies that are already licensed to treat other diseases, such as cancer and autoimmune diseases, are being tested for the treatment of MS. Additionally, novel targets are currently being investigated for MS. The therapeutic use of monoclonal antibodies was initially viewed with great scepticism owing to the high rates of sensitisation against mouse proteins, their pharmacokinetic properties, and the difficulties in their production. However, most of these problems have been overcome, and monoclonal antibodies are now among the most promising therapies for MS.