Valentina Damato

Efficacy and safety of rituximab for myasthenia gravis: a systematic review and meta-analysis

AbstractMyasthenia gravis is an autoimmune disorder of the neuromuscular junction caused by circulating antibodies specif ic for the post-synaptic acetylcholine receptor or, in a minority of cases, for the muscle-specific tyrosine-kinase and the low-density lipoprotein receptor-related protein 4. A wide range of symptomatic and immunosuppressive treatments is currently available for MG patients with variable outcome. However, most immunosuppressive treatments are characterized by delayed onset of action and in some cases are not sufficient to induce stable remission of the disease. Rituximab (RTX) is a chimaeric monoclonal antibody specific for the CD20 B-cell surface antigen. Recent studies have provided evidence that RTX may be an effective treatment for patients with myasthenia gravis (MG) who are refractory to standardized immunosuppressive therapy. We performed a systematic review and a meta-analysis of the efficacy and safety of RTX in myasthenia gravis considering the potential predictive factors related to patients’ response to RTX in this disease.

Efficacy and Safety of Rituximab Therapy in Neuromyelitis Optica Spectrum Disorders: A Systematic Review and Meta-analysis

Importance Neuromyelitis optica spectrum disorders (NMOSDs) are autoimmune astrocytopathies characterized by predominant involvement of the optic nerves and spinal cord. In most patients, an IgG autoantibody binding to astrocytic aquaporin 4, the principal water channel of the central nervous system, is detected. Rituximab, a chimeric monoclonal antibody specific for the CD20 B-lymphocyte surface antigen, has been increasingly adopted as a first-line off-label treatment for patients with NMOSDs. Objective To perform a systematic review and a meta-analysis of the efficacy and safety of rituximab use in NMOSDs, considering the potential predictive factors related to patient response to rituximab in this disease. Evidence Review English-language studies published between January 1, 2000, and July 31, 2015, were searched in the MEDLINE, Central Register of Controlled Trials (CENTRAL), and clinicaltrials.gov databases. Patient characteristics, outcome measures, treatment regimens, and recorded adverse effects were extracted. Findings Forty-six studies were included in the systematic review. Twenty-five studies that included 2 or more patients with NMOSDs treated with rituximab were included in the meta-analysis. Differences in the annualized relapse rate ratio and Expanded Disability Status Scale score before and after rituximab therapy were the main efficacy measures. Safety outcomes included the proportion of deaths, withdrawals because of toxic effects, and adverse effects. Results Among 46 studies involving 438 patients (381 female and 56 male [sex was not specified in 1 patient]; mean age at the outset of treatment, 32 years [age range, 2-77 years]), rituximab therapy resulted in a mean (SE) 0.79 (0.15) (95% CI, -1.08 to -0.49) reduction in the mean annualized relapse rate ratio and a mean (SE) 0.64 (0.27) (95% CI, -1.18 to -0.10) reduction in the mean Expanded Disability Status Scale score. A significant correlation was observed between disease duration and the Expanded Disability Status Scale score. Adverse effects were recorded in 114 of 438 (26%) patients treated with rituximab. Specifically, 45 patients (10.3%) experienced infusion-related adverse effects, 40 patients (9.1%) had an infection, 20 patients (4.6%) developed persistent leukopenia, 2 patients (0.5%) were diagnosed as having posterior reversible encephalopathy, and 7 patients (1.6%) died. Conclusions and Relevance This systematic review and meta-analysis provides evidence that rituximab therapy reduces the frequency of NMOSD relapses and neurological disability in patients with NMOSDs. However, the safety profile suggests caution in prescribing rituximab as a first-line therapy.

Distinctive clinical and neuroimaging characteristics of longitudinally extensive transverse myelitis associated with aquaporin-4 autoantibodies

Longitudinally extensive transverse myelitis (LETM) is a characteristic feature of Neuromyelitis Optica (NMO), but it can also occur in several other inflammatory diseases of the central nervous system (CNS). An IgG autoantibody that binds to aquaporin-4 (AQP4), the predominant water channel of the CNS, is a reliable biomarker of the NMO spectrum disorders, and if detected predicts the recurrence of the myelitis. In this study, we compared the clinical and neuroimaging characteristics of AQP4-IgG+ and AQP4-IgG− LETM patients. Thirty-seven first-ever LETM patients were retrospectively evaluated and divided into two groups according to the presence of AQP4 autoantibodies. AQP4-IgG was detected in the serum and in the cerebrospinal fluid of sixteen patients. The female to male ratio was higher in AQP4-IgG+ patients. Intractable nausea and vomiting and paroxysmal tonic spasms often accompanied the LETM in AQP4-IgG+ patients. T2-weighted spinal cord MRI revealed that inflammatory lesions extending into the brainstem and involving the central grey matter occurred more frequently in AQP4-IgG+ LETM patients. Hypointense lesions on T1-weighted spinal cord MRI were detected more frequently in the seropositive group, and their presence correlated with attack severity. In conclusion, this study provides clinical and spinal cord neuroimaging clues that can help distinguishing AQP4-IgG+ LETM patients.

Cerebellar degeneration associated with mGluR1 autoantibodies as a paraneoplastic manifestation of prostate adenocarcinoma

Subacute cerebellar degeneration associated with metabotropic glutamate receptor type 1 (mGluR1) autoantibodies is an uncommon syndrome known to be part of the spectrum of paraneoplastic cerebellar degenerations associated with neuronal autoantibodies. We describe a patient with prostate adenocarcinoma who developed a subacute cerebellar ataxia. Autoantibodies specific to mGluR1 were detected in patients serum and cerebrospinal fluid (CSF). Immunohistochemistry analyses of patients prostate adenocarcinoma revealed abundant mGluR1 expression in luminal acinar epithelial cells and binding of patients IgGs to tumoral mGluR1. These findings suggest that cerebellar degeneration associated with mGluR1 antibodies can be a paraneoplastic accompaniment of prostate adenocarcinoma.

Tissue-Infiltrating Lymphocytes Analysis Reveals Large Modifications of the Duodenal “Immunological Niche” in Coeliac Disease After Gluten-Free Diet

OBJECTIVES:The role of T lymphocytes in the pathogenesis of Celiac disease (CD) is well established. However, the mechanisms of T-cell involvement remain elusive. Little is known on the distribution of T subpopulations: T-regulatory (Treg), Th17, CD103, and CD62L cells at disease onset and after gluten-free diet (GFD). We investigated the involvement of several T subpopulations in the pathogenesis of CD.METHODS:We studied T cells both in the peripheral blood (PB) and the tissue-infiltrating lymphocytes (TILs) from the mucosa of 14 CD patients at presentation and after a GFD, vs. 12 controls.RESULTS:Our results extend the involvement of Treg, Th1, and Th17 cells in active CD inflammation both in the PB and at the TILs. At baseline, Tregs, Th1, and Th17 cells are significantly higher in active CD patients in TILs and PB. They decreased after diet. Moreover, CD62L+ TILs were increased at diagnosis as compared with GFD patients.CONCLUSIONS:Our data show significant modifications of the above-mentioned subpopulations both in the PB and TILs. The increase of suppressive Tregs in active CD both in the PB and TILs is intriguing. T lymphocytes are known to have a crucial role in the pathogenesis of CD. We have shown that gluten trigger results in systemic recruitment of T lymphocytes, the unbalance between pro-inflammatory and anti-inflammatory populations and the increase of CD62L+ T cells in TILs. Our results delineate a more complete picture of T-cell subsets in active vs. GFD disease. Our data of T-cell subpopulations, combined with known data on cytokine production, support the concept that duodenal micro-environment acts as an immunological niche and this recognition may have an important role in the diagnosis, prognosis and therapeutical approach of CD.

The detection of neural autoantibodies in patients with antiepileptic-drug-resistant epilepsy predicts response to immunotherapy

The detection of antibodies binding neural antigens in patients with epilepsy has led to the definition of ‘autoimmune epilepsy’. Patients with neural antibodies not responding to antiepileptic drugs (AEDs) may benefit from immunotherapy. Aim of this study was to evaluate the frequency of autoantibodies specific to neural antigens in patients with epilepsy and their response to immunotherapy.

Disease specific enrichment of circulating let-7 family microRNA in MuSK + myasthenia gravis

Myasthenia gravis (MG) patients with antibodies against the muscle specific tyrosine kinase (MuSK+) have predominantly involvement of cranio-bulbar muscles and do not display thymus pathology, as do acetylcholine receptor antibody seropositive (AChR+) MG patients. In search of novel biomarkers for MuSK+ MG, we evaluated circulating serum microRNAs. Four analyzed microRNAs were specifically elevated in MuSK+ MG patient serum samples: let-7a-5p, let-7f-5p, miR-151a-3p and miR-423-5p. The circulating microRNA profile in MuSK+ MG differs from the profile previously observed in the serum of AChR+ MG, thus indicating the etiological difference between these two entities. We propose that the identified microRNAs could serve as potential serum biomarkers for MuSK+ MG.

3,4-Diaminopyridine may improve myasthenia gravis with MuSK antibodies

Myasthenia gravis (MG) with antibodies to the muscle-specific tyrosine kinase receptor (MuSK) is characterized by prominent cranial and bulbar weakness. The disease course is often severe and some patients develop permanent, disabling symptoms despite long-term immunosuppression.1 In patients with MuSK MG, the administration of acetylcholinesterase inhibitors (AChE-I) is poorly effective and often associated with clinical and electrophysiologic signs of cholinergic hypersensitivity.2 3,4-Diaminopyridine (3,4-DAP) improves neuromuscular transmission (NMT) by increasing quantal release. We report the case of an adult patient with MuSK MG who was responsive to and tolerant of 3,4-DAP.

Neuromyelitis optica spectrum disorder as a paraneoplastic manifestation of lung adenocarcinoma expressing aquaporin-4

Background: The observations of neuromyelitis optica spectrum disorders (NMOSD) occurring in the setting of cancer suggest that aquaporin-4 (AQP4) autoimmunity may in some cases be paraneoplastic. Results: We describe a 72-year-old patient who developed a longitudinally extensive transverse myelitis associated with AQP4 autoantibodies in the setting of a lung adenocarcinoma recurrence. AQP4 expression was demonstrated in tumor cells. IgG in patient’s cerebrospinal fluid bound to tumor cells co-localizing with AQP4 immunoreactivity. Conclusions and relevance: This case expands the spectrum of paraneoplastic AQP4 autoimmunity highlighting the importance of considering an oncological screening in patients with late-onset NMOSD.

Circulating CD56dim NK cells expressing perforin are increased in progressive multiple sclerosis

In this study we evaluated the percentages of CD3(-)CD56(bright), CD3(-)CD56(dim), CD3(-)CD56(bright)perforin(+) and CD3(-)CD56(dim)perforin(+) Natural Killer (NK) cells in peripheral blood from untreated secondary progressive (SP) and primary progressive (PP) multiple sclerosis (MS) patients and age and sex matched healthy subjects. Both PPMS patients and SPMS patients showed increased percentages of circulating CD3(-)CD56(dim)perforin(+) NK cells than healthy subjects. The increased percentage of CD3(-)CD56(dim) NK cells expressing perforin in patients affected by the progressive forms of MS suggests a possible role of this NK cell subpopulation in the pathogenesis of the disease.