Littérature scientifique sur le sujet « Onconeuronal antigen »

Paraneoplastic neurological syndromes (PNS) are remote effects of tumors on the nervous system. They can strike at single or at multiple sites of the central nervous system (CNS) and the peripheral nervous system, and often appear before the detection of cancer. PNS can be disabling and debilitating and may be either an additional burden to cancer or the cause of death. The PNS Euronetwork group has collected a series of approximately 1,000 patients in several European centers. This study is the largest systematic series of patients with PNS and, for the first time, can answer questions about the most frequent PNS, their detailed symptoms, associated antibodies, and the types of underlying tumors. The clinical course and laboratory findings for many PNS suggest an autoimmune pathogenesis; however, research into this heterogeneous immunological relationship has been evolving over recent decades. The classic syndromes are antigen-target-oriented syndromes such as myasthenia gravis (MG), Lambert-Eaton myasthenic syndrome (LEMS), and ion channel-mediated diseases. Onconeuronal antibodies constitute a large group of PNS, characterized by the appearance of specific antibodies, defined clinical signs and often an association with specific tumors. In recent years, a new group of antibodies directed at surface antigens as receptors has been identified. Finally, there is a long list of ‘other’ PNS, which are evident to clinicians but which have no pathogenetic explanation. Examples include the mild terminal neuropathies and sarcopenia in cancer patients. In addition to the emerging classification based on pathophysiology, other new syndromes and symptoms have appeared, including apnea in brainstem encephalitis, a neuropsychiatric spectrum of limbic encephalitis, and increased knowledge about LEMS. Two important aspects warrant attention: some PNS respond to therapy and not all paraneoplastic-like syndromes are tumor related. This view is based on the current understanding of immune pathogenesis and on the enlarged spectrum of PNS.

Paraneoplastic neurological syndromes (PNS) are remote effects of tumours on the nervous system. They can strike at single or at multiple sites of the central nervous system (CNS) and the peripheral nervous system, and often appear before the detection of cancer. PNS can be disabling and debilitating and may be either an additional burden to cancer or the cause of death. The PNS Euronetwork group has collected a series of approximately 1,000 patients in several European centres. This study is the largest systematic series of patients with PNS and, for the first time, can answer questions about the most frequent PNS, their detailed symptoms, associated antibodies and the types of underlying tumours. The clinical course and laboratory findings for many PNS suggest an autoimmune pathogenesis; however research into this heterogeneous immunological relationship has been evolving over recent decades. The classical syndromes are antigen-target-oriented syndromes such as myasthenia gravis (MG), Lambert-Eaton myasthenic syndrome (LEMS) and ion channelmediated diseases. Onconeuronal antibodies constitute a large group of PNS, characterised by the appearance of specific antibodies, defined clinical signs and often an association with specific tumours. In recent years, a new group of antibodies directed at surface antigens as receptors has been identified. Finally there is a long list of ‘other’ PNS, which are evident to clinicians but which have no pathogenetic explanation. Examples include the mild terminal neuropathies and sarcopoenia in cancer patients. In addition to the emerging classification based on pathophysiology, other new syndromes and symptoms have appeared, including apnoea in brainstem encephalitis, a neuropsychiatric spectrum of limbic encephalitis and increased knowledge about LEMS. Two important aspects warrant attention: some PNS respond to therapy and not all paraneoplastic-like syndromes are tumour related. This view is based on the current understanding of immune pathogenesis and on the enlarged spectrum of PNS.

Background and ObjectiveIn people with multiple sclerosis (pwMS), concern for potential disease exacerbation or triggering of other autoimmune disorders contributes to vaccine hesitancy. We assessed the humoral and T-cell responses to SARS-CoV-2 after mRNA vaccination, changes in disease activity, and development of antibodies against central or peripheral nervous system antigens.MethodsThis was a prospective 1-year longitudinal observational study of pwMS and a control group of patients with other inflammatory neurologic disorders (OIND) who received an mRNA vaccine. Blood samples were obtained before the first dose (T1), 1 month after the first dose (T2), 1 month after the second dose (T3), and 6 (T4), 9 (T5), and 12 (T6) months after the first dose. Patients were assessed for the immune-specific response, annualized relapse rate (ARR), and antibodies to onconeuronal, neural surface, glial, ganglioside, and nodo-paranodal antigens.ResultsAmong 454 patients studied, 390 had MS (22 adolescents) and 64 OIND; the mean (SD) age was 44 (14) years; 315 (69%) were female; and 392 (87%) were on disease-modifying therapies. Antibodies to the receptor-binding domain were detected in 367 (86%) patients at T3 and 276 (83%) at T4. After a third dose, only 13 (22%) of 60 seronegative patients seroconverted, and 255 (92%) remained seropositive at T6. Cellular responses were present in 381 (93%) patients at T3 and in 235 (91%) patients at T6 including all those receiving anti-CD20 therapies and in 79% of patients receiving fingolimod. At T3 (429 patients) or T6 (395 patients), none of the patients had developed CNS autoantibodies. Seven patients had neural antibodies that were already present before immunization (3 adult patients with MS had MOG-IgG, 2 with MG and 1 with MS had neuronal cell surface antibodies [unknown antigen], and 1 with MS had myelin antibody reactivity [unknown antigen]. Similarly, no antibodies against PNS antigens were identified at T3 (427 patients). ARR was lower in MS and not significantly different in patients with OIND. Although 182 (40%) patients developed SARS-CoV-2 infection, no cases of severe COVID-19 or serious adverse events occurred.DiscussionIn this study, mRNA COVID-19 vaccination was safe and did not exacerbate the autoimmune disease nor triggered neural autoantibodies or immune-mediated neurologic disorders. The outcome of patients who developed SARS-CoV-2 infection was favorable.

10582 Background: At present, paraneoplasmatic neurological syndroms (PNS) are thought to be autoimmunological disorders. Neurological symptoms in PNS result from the disturbance of the nervous system, with a participation of the immune response triggered by the aberrant expression of the so-called onconeuronal antigens of a tumour. Very important for PNS diagnostics is the investigation of antineuronal antibodies (ANA) in the serum. Different types of ANA are frequently associated with specific tumors and with specific neurological syndromes.Investigations of serum ANA in patients with breast cancer with the symptoms of PNS. Methods: Investigations of ANA in serum were performed with the indirect immunofluorescence test but the type of ANA was analyzed by the Western Blot (WB) method . The presence of these antibodies which are included to the group of “the so called well characterized” is believed to be a definite (95 – 100%) determinant of the PNS diagnosis. Results: We examined 147 patients with breast cancer suspected to have PNS, hospitalized at Breast Cancer Clinic of the Institute of Oncology in Warsaw. The immunofluorescence test was positive in 92 patients, however in 24 patients the WB occurrence of “the well characterized” antibodies was found. In this group we observed: in 4 patients the cerebellar degeneration (anti-Yo, anti-Ma2); in 6 patients brainstem encephalitis and encephalomyelitis combined with sensory neuropathy (anti-Ma2, anti-CV2, anti-Yo, anti-Hu, anti-Ri); 4 myastenic syndrome (anti-Hu,anti-Ri,anti-Ma2/Ta); 5 sensory neuropathy (anti-Hu, anti-Yo, anti-Ma2, anti-Ri); and in single cases we also observed polyneuropathy: Guillain-Barre (Ma2): Miller-Fisher syndrom (anti-Ma2/Ta); cancer-associated retinopathy (anti-Yo); dermatomyositis (anti-Ri) and scleroderma (anti-Yo). Conclusions: Our analysis indicates that the investigation of the presence of ANA in the serum is the important in the diagnosis of PNS in patients with breast cancer. The types of ANA correspond to the individual paraneoplastic neurological syndromes which opens the proper methods of treatment in PNS.

The collapsin response-mediator protein-5 (CRMP5) autoantibody is a recognised biomarker for small cell lung cancer associated neurological Paraneoplasia.We describe a 79-year-old lady, who presented with right hemi-chorea. This progressed over one month, becoming bilateral and rendering the patient bedbound.MRI revealed bilateral signal change within the caudate and lentiform nuclei. CT chest detected mediastinal lymphadenopathy, while PET identified pulmonary malignancy with radiological staging T1bN3M0. Serum CRMP5 antibodies were positive.Haloperidol and intravenous methylprednisolone lead to some improvement in Chorea and mobility. However, visual acuity deteriorated to finger counting. Fundoscopy revealed mild cataracts, while visual evoked potentials were very delayed on the right and absent on the left, suggesting optic neuropathy.She deteriorated with leg pain, weakness, and loss of tendon reflexes, as well as cognitive decline and visual hallucinations. Clinically this raised suspicion of radiculoneuropathy and encephalopathy respectively. Whilst retaining capacity the patient refused further investigations and treatment. She was discharged to a nursing home and died 6 months later.CRMP5 antibodies, targeting intracellular antigens, precipitate an onconeuronal autoimmune process through mechanisms not fully understood. We report a case of combined chorea, optic neuropathy, peripheral neuropathy, and encephalopathy, which highlights the potential for CRMP5 to cause multifocal neurological dysfunction.

Paraneoplastic neurological syndromes (PNS) are the immune-mediated effects of a remote cancer and are characterised by an autoantibody response against antigens expressed by the tumour. Classically, well-characterised ‘onconeuronal’ antibodies target intracellular antigens and hence cannot access their antigens across intact cell membranes. The pathogenic mediators are likely to be neuronal-specific T cells. There is a variable response to immunotherapies and the clinical syndrome helps to direct the search for a specific set of tumours. By contrast, many newly emerging autoantibodies with oncological associations target cell surface epitopes and can exert direct pathogenic effects on both the central and peripheral nervous systems. Patients with these cell-surface directed autoantibodies often clearly respond to immunotherapies. Overall, the clinical, serological and oncological features in an individual patient helps determine the clinical relevance of the syndrome and hence guide its management. We summarise current knowledge and a practical approach to the investigation, diagnosis, treatment and outcomes of patients with suspected PNS.

BackgroundGlioblastoma (GBM) is the most common primary brain tumor in adulthood. Initial diagnosis is generally based on clinical and MRI findings, which may be misinterpreted as other neurological pictures, including autoimmune encephalitis (AE). AE is a heterogeneous group of neuroinflammatory diseases due to the presence of auto-antibodies targeting antigens on neuronal synaptic or cell surface. In the present report, we describe two peculiar cases of GBM initially misdiagnosed as AE, focusing on the diagnostic pitfalls and the treatment strategies.MethodsWe report the case of two patients with high-grade brain tumors, initially misdiagnosed and treated for AE. Clinical, laboratory, and neuroradiological data are discussed in terms of differential diagnosis between AE and GBM.ResultsThe presence of atypical brain MRI findings and the unresponsiveness to immunosuppressive treatment are major red flags in the differential diagnosis between AE and GBM. In these cases, a brain biopsy is necessary to confirm the diagnosis.ConclusionsAtypical brain tumor presentation causes a diagnostic and therapeutic delay. A positive onconeural autoantibodies result should always be interpreted cautiously, considering the possibility of a false-positive test. A brain biopsy is mandatory for a definite diagnosis.

Introduction : Les syndromes neurologiques paranéoplasiques (SNP) sont des maladies auto-immunes rares affectant le système nerveux central, associées à la présence d'un cancer et satellites de la réponse immune anti-tumorale. Ces pathologies sont associées à la présence d’auto-anticorps, dont la détection dans le sang ou le LCR des patients permet de poser le diagnostic. Ces auto-anticorps sont dirigés contre une protéine du soi, exprimée à la fois dans la tumeur et dans le SNC, appelée l'antigène onconeuronal. Les facteurs amenant à la rupture de tolérance immune dans les SNP restent inconnus à ce jour. Des travaux récents dans les cancers de l'ovaire et du sein associés au syndrome Yo ont permis de montrer que les antigènes onconeuronaux Yo sont surexprimés dans la tumeur. De plus, il existe fréquemment des mutations et des gains de nombre de copie des gènes codant pour les antigènes Yo. Ces altérations des antigènes onconeuronaux ne sont pas retrouvées dans les autres SNP (cancers du poumon associé aux anticorps anti-Hu par exemple) et les facteurs déclenchants de la rupture de tolérance immune dans ces cancers sont encore plus mystérieux. Les objectifs de ce travail de thèse sont d'approfondir l'analyse du lien entre la tumeur et l'auto-immunité paranéoplasique. Le premier axe d'étude était la comparaison de deux couples de syndromes associés au même type de cancer (syndrome Ri et Yo associés à des cancers du sein, syndrome RGS8 et DNER associés à des lymphomes de Hodgkin). Le deuxième axe portait sur l'analyse des potentielles altérations des antigènes onconeuronaux dans le syndrome Ri.Méthodes : La première étude de ce travail de thèse portait sur une cohorte de cancers du sein associés au syndrome de Ri, utilisant des données clinico-pathologiques, génomiques et transcriptomiques. La seconde étude portait sur patients atteints du syndrome RGS8 et utilisait des données clinico-pathologiques et le séquençage par immunoprécipitation de Phage (PhIP-seq).Résultats : Les cancers du sein Ri sont d’un sous-type particulier (Luminal B) différent de celui observé dans les cancers Yo (HER2-driven) et présentent des particularités génétiques qui les différencient des tumeurs Luminal B contrôles. Aucune altération des antigènes onconeuronaux n'a été retrouvée dans les tumeurs Ri. En revanche, la réaction immune anti-tumorale, composée majoritairement d’un infiltrat lymphocytaire B intra-tumoral, est comparable à celle observée dans les cancers du sein Ri et Yo.Concernant le syndrome RGS8, deux patients présentent un lymphome de Hodgkin d'un sous-type spécifique rare nodulaire à prédominance lymphocytaire, différents des formes nodulaires-sclérosantes classiques associées au syndrome DNER. Les auto-anticorps détectés chez tous les patients enrichissaient le même épitope sur la protéine RGS8, une protéine intracellulaire physiologiquement exprimée dans les cellules de Purkinje mais dont on retrouve également une expression ectopique dans les cellules de lymphome des patients atteints du syndrome RGS8.Conclusion : chaque syndrome paranéoplasique est associé à un sous-type spécifique de cancer présentant des particularités génétiques. Les altérations de l'antigène (surexpression, variation du nombre de copies et mutation) peuvent déclencher la rupture de la tolérance immune mais ne sont pas présentes dans tous les syndromes paranéoplasiques. L'immunité antitumorale associée aux PNS est atypique du fait de l’importance de l’infiltrat lymphocytaire B. Ces résultats constituent un pas en avant dans notre compréhension de l'immunité paranéoplasique et fournissent des indices sur les marqueurs prédictifs potentiels qui pourraient être utiles pour personnaliser la prise de décision médicale en immunothérapie anti-cancéreuse
Background: Paraneoplastic cerebellar degeneration (PCD) are rare autoimmune disorders affecting an otherwise immune-privileged site: the central nervous system. This autoimmunity is associated with the presence of a cancer and is satellite of the anti-tumor immune response, the B-cell response originating a secretion of autoantibodies that are diagnostic hallmarks of these disorders. These autoantibodies are directed against a protein expressed both in the tumor and in the CNS, the so-called onconeural antigen. The triggers of the immune tolerance breakdown and the exact relationship between the tumor, the immune system and the neurological symptoms are still not totally understood. Recent studies have allowed to show that in some tumors associated with paraneoplastic syndromes (namely ovarian and breast cancers associated with Yo syndrome), the onconeural antigen is overexpressed due to the presence of a gain or amplification in the gene locus and may present mutations while in others, none of these alterations of the onconeural antigen are present (e.g. lung cancers in Hu syndrome). The objectives of this thesis work are to further analyze the link between the tumor and the paraneoplastic autoimmunity by comparing two syndromes associated with the same type of cancer (Ri and Yo syndrome associated with breast cancers, RGS8 and DNER syndrome associated with Hodgkin’s lymphoma) and to search for antigen alterations in another syndrome (Ri syndrome).Methods: we conducted two studies within the frame of this thesis work. A first study on a clinical and pathological cohort of breast cancers associated with Ri-syndrome using clinicopathological data, DNA-sequencing, and whole-transcriptome analysis. A second analysis on three patients with RGS8-syndrome using clinicopathological data and Phage Immunoprecipitation sequencing (PhIP-seq).Results: Ri breast cancers were a subtype different than one observed in Yo with uncommon genetic features that singularize them among their subtype. Neither overexpression nor genetic alteration of the Ri onconeural antigens were found in Ri breast cancers. Conversely, the anti-tumor immune reaction in Ri breast cancers was similar to the one found in Yo: an atypical intratumoral B-cell infiltration.Concerning RGS8 paraneoplastic cerebellar degeneration, two patients presented with a Hodgkin lymphoma of the rare specific subtype called nodular lymphocyte-predominant Hodgkin lymphoma, whereas DNER is associated with the classical nodular-sclerosing form. Autoantibodies detected in all patients enriched the same epitope on the RGS8 protein, which is an intracellular protein physiologically expressed in Purkinje cells but also ectopically expressed specifically in lymphoma cells of patients with RGS8-syndrome.Conclusion: each paraneoplastic syndrome is associated with a specific histomolecular subtype of cancer with uncommon genetic features, which provides the first evidence of a tight link between oncogenesis and paraneoplastic immunity. Alterations of the antigen (overexpression, copy number variation and mutation) may be the mechanism of immune tolerance breakdown in several different syndromes but are not ubiquitous. The antitumor immunity seems to be an atypical B-cell response in several subtypes irrespective of the tumor type and antigen alterations. These results are a step forward in our understanding of paraneoplastic immunity and provide clues on potential predictive markers of paraneoplastic immunity that may be of use in personalizing medical decision of immunotherapy in the field of oncology