Paraneoplastic neurological syndromes

Cancer Frequency in MuSK Myasthenia Gravis and Histological Evidence of Paraneoplastic Etiology

Cancer frequency in muscle-specific kinase myasthenia gravis (MuSK-MG) has not yet been explored and the mechanisms leading to the formation of MuSK IgG remain elusive. We aimed to explore cancer frequency in MuSK-MG patients and to assess MuSK expression in cancer cells from 2 tumors occurred in this cohort. Immunohistochemistry on tumor specimens revealed the expression of MuSK in the cancer cells from primary mediastinal B cell lymphoma and endometrial carcinoma. Twenty-one males and 73 females were enrolled. Fifteen cancers occurred in 13 of 94 patients (13.8%). Patients with cancer were significantly older at time of MuSK-MG onset. ANN NEUROL 2024;96:1020-1025.

Surgical procedures and plasma exchange for ovarian teratoma-associated anti-N-methyl D-aspartate receptor encephalitis: a case report and review of literature

We reported a case of ovarian teratoma-associated Anti-N-methyl-D-aspartate receptor (anti-NMDAR) encephalitis with recurrent epileptic seizures and disturbance of consciousness. Although surgical excision of the tumor remains the established standard of care, unlike other reported cases, the patient exhibited limited response to early oophorocystectomy, as well as IVIG and steroid therapy; however, a favorable response was observed with Plasma exchange (PE) initiated on postoperative day 12. Literature review revealed no definite recommended surgical extent for ovarian teratomas, and outstanding improvement in patients with anti-NMDAR encephalitis following PE. Our case raises the question regarding the optimal surgical extent for tumor resection, necessitating careful consideration when deciding between oophorectomy and adnexectomy as the preferred surgical procedure for anti-NMDAR encephalitis in female teens and adults. Furthermore, for refractory patients who fail to respond following tumor resection, PE can be performed early instead of immediately initiating second-line therapy.

Targeting Underlying Inflammation in Carcinoma Is Essential for the Resolution of Depressiveness

In modern clinical practice and research on behavioral changes in patients with oncological problems, there are several one-sided approaches to these problems. Strategies for early detection of behavioral changes are considered, but they must take into account the specifics of the localization and phase in the course and treatment of somatic oncological disease. Behavioral changes, in particular, may correlate with systemic proinflammatory changes. In the up-to-date literature, there are a lot of useful pointers on the relationship between carcinoma and inflammation and between depression and inflammation. This review is intended to provide an overview of these similar underlying inflammatory disturbances in both oncological disease and depression. The specificities of acute and chronic inflammation are considered as a basis for causal current and future therapies. Modern therapeutic oncology protocols may also cause transient behavioral changes, so assessment of the quality, quantity, and duration of behavioral symptoms is necessary to prescribe adequate therapy. Conversely, antidepressant properties could be used to ameliorate inflammation. We will attempt to provide some impetus and present some unconventional potential treatment targets related to inflammation. It is certain that only an integrative oncology approach is justifiable in modern patient treatment.

Real-world application of the updated diagnostic criteria for paraneoplastic neurological syndromes

Following recent discoveries, diagnostic criteria for paraneoplastic neurological syndromes (PNS) have been recently updated. However, how the criteria impact PNS diagnosis is still unclear. We retrospectively applied the previously existing 2004 criteria (2004-c) and the updated 2021 diagnostic criteria (2021-c) to 74 patients with suspect PNS. The 2021 criteria were highly sensitive (88%) and specific (80%). There was good concordance between the definite PNS group (2004-c) and the definite plus probable PNS group (2021-c). The inter-rater reliability for the 2021-c was excellent. The application of the 2021 criteria improves the diagnosis of patients with PNS.

Anti-N-methyl-D-aspartate receptor encephalitis associated with chronic myelogenous leukemia, causality or coincidence? A case report

Background

Anti-N-methyl-D-aspartate receptor (NMDAR) encephalitis is the most frequent autoimmune paraneoplastic encephalitis, and is primarily associated with ovarian teratomas. Here, we report the first case of a patient diagnosed with chronic myelogenous leukemia (CML) during the recovery phase of anti-NMDAR encephalitis.

Case presentation

The patient was admitted with fever, headache, and seizures. Brain MRI revealed a cerebrospinal fluid (CSF)-containing arachnoid cyst in the left temporal lobe with no other abnormal signals. EEG showed diffuse background slowing in the delta-theta range. The patient tested positive for anti-NMDAR antibodies in both the serum and CSF. One year after the onset of encephalitis, the patient was referred to the Department of Hematology for extreme leukocytosis. Karyotype analysis showed the presence of Philadelphia chromosome t(9;22)(q34;q11). Quantitative reverse transcriptase PCR analysis further identified BCR/ABL1 fusion transcripts; thus, CML was diagnosed.

Conclusions

To the best of our knowledge, this is the first case of anti-NMDAR encephalitis associated with CML. This report should alert clinicians to consider CML as a malignancy that is possibly associated with limbic encephalitis.

Clinical features and outcome of patients with autoimmune cerebellar ataxia evaluated with the Scale for the Assessment and Rating of Ataxia

BACKGROUND AND PURPOSE

This study was undertaken to assess the long-term outcome of patients with paraneoplastic and non paraneoplastic autoimmune cerebellar ataxia (ACA) using the Scale for the Assessment and Rating of Ataxia (SARA).

METHODS

Patients with subacute cerebellar ataxia admitted to our institution between September 2012 and April 2020 were prospectively recruited. Serum and/or cerebrospinal fluid was tested for neural autoantibodies by indirect immunofluorescence on mouse brain, cell-based assays, and radioimmunoassay. SARA and modified Rankin Scale (mRS) score were employed to assess patients' outcome.

RESULTS

Fifty-five patients were recruited, of whom 23 (42%) met the criteria for cerebellar ataxia of autoimmune etiology. Neural autoantibodies were detected in 22 of 23 patients (Yo-immunoglobulin G [IgG], n = 6; glutamic acid decarboxylase 65-IgG, n = 3; metabotropic glutamate receptor 1-IgG, n = 2; voltage-gated calcium channel P/Q type-IgG, n = 2; Hu-IgG, n = 1; glial fibrillary acidic protein-IgG, n = 1; IgG-binding unclassified antigens, n = 7). Thirteen patients were diagnosed with paraneoplastic cerebellar syndrome (PCS) and 10 with idiopathic ACA. All patients received immunotherapy. Median SARA score was higher in the PCS group at all time points (p = 0.0002), while it decreased significantly within the ACA group (p = 0.049) after immunotherapy. Patients with good outcome (mRS ≤ 2) had less neurological disability (SARA < 15) at disease nadir (p = 0.039) and presented less frequently with paraneoplastic neurological syndrome (p = 0.0028). The univariate linear regression model revealed a good correlation between mRS and SARA score both at disease onset (p < 0.0001) and at last follow-up (p < 0.0001). SARA score < 11 identified patients with good outcome.

CONCLUSIONS

Patients with idiopathic ACA significantly improved after immunotherapy. SARA score accurately reflects patients' clinical status and may be a suitable outcome measure for patients with ACA.

Anti-neuron antibody syndrome: clinical features, cytokines/chemokines and predictors

BACKGROUND

Neuroimmunology is a rapidly expanding field, and there have been recent discoveries of new antibodies and neurological syndromes. Most of the current clinical studies have focused on disorders involving one specific antibody. We have summarized a class of antibodies that target common neuronal epitopes, and we have proposed the term "anti-neuron antibody syndrome" (ANAS). In this study, we aimed to clarify the clinical range and analyse the clinical features, cytokines/chemokines and predictors in ANAS.

METHODS

This was a retrospective cohort study investigating patients with neurological manifestations that were positive for anti-neuron antibodies.

RESULTS

A total of 110 patients were identified, of which 43 patients were classified as having autoimmune encephalitis (AE) and the other 67 were classified as having paraneoplastic neurological syndrome (PNS). With regards to anti-neuron antibodies, 42 patients tested positive for anti-N-methyl-D-aspartate receptor (NMDAR) antibody, 19 for anti-Hu, 14 for anti-Yo and 12 for anti-PNMA2 (Ma2). There were significant differences between the ANAS and control groups in serum B cell-activating factor (BAFF) levels and in cerebrospinal fluid (CSF) C-X-C motif chemokine10 (CXCL10), CXCL13, interleukin10 (IL10), BAFF and transforming growth factor β1 (TGFβ1) levels. Predictors of poor outcomes included having tumours (P = 0.0193) and having a chronic onset (P = 0.0306), and predictors of relapses included having lower levels of CSF BAFF (P = 0.0491) and having a larger ratio of serum TGFβ1/serum CXCL13 (P = 0.0182).

CONCLUSIONS

Most patients with ANAS had a relatively good prognosis. Having tumours and a chronic onset were both associated with poor outcomes. CSF BAFF and the ratio of serum TGFβ1/serum CXCL13 were associated with relapses.

The Association of Ovarian Teratoma and Anti-N-Methyl-D-Aspartate Receptor Encephalitis: An Updated Integrative Review

Ovarian teratomas are by far the most common ovarian germ cell tumor. Most teratomas are benign unless a somatic transformation occurs. The designation of teratoma refers to a neoplasm that differentiates toward somatic-type cell populations. Recent research shows a striking association between ovarian teratomas and anti-N-methyl-D-aspartate receptor (anti-NMDAR) encephalitis, a rare and understudied paraneoplastic neurological syndrome (PNS). Among teratomas, mature teratomas are thought to have a greater relevance with those neurological impairments. PNS is described as a neurologic deficit triggered by an underlying remote tumor, whereas anti-NMDAR encephalitis is characterized by a complex neuropsychiatric syndrome and the presence of autoantibodies in cerebral spinal fluid against the GluN1 subunit of the NMDAR. This review aims to summarize recent reports on the association between anti-NMDAR encephalitis and ovarian teratoma. In particular, the molecular pathway of pathogenesis and the updated mechanism and disease models would be discussed. We hope to provide an in-depth review of this issue and, therefore, to better understand its epidemiology, diagnostic approach, and treatment strategies.

Assessing the role of a tissue-based assay in the diagnostic algorithm of autoimmune encephalitis

Tissue-based assay (TBA) is a widely-used method to detect neural autoantibodies, but the diagnostic accuracy for autoimmune encephalitis (AE) has not yet been adequately measured. We retrospectively evaluated the sensitivity and specificity of an indirect immunofluorescence TBA (IIF-TBA) in 159 patients with suspected AE. Serum and cerebrospinal fluid (CSF) specimens were collected and tested from December 2012 to September 2020. In the paired sample analysis, serum testing showed higher sensitivity than CSF, while the latter had higher specificity. Based on these results, we clarify the advantages of using a TBA as the principal screening method for patients with suspected AE.

Pathophysiology of paraneoplastic and autoimmune encephalitis: genes, infections, and checkpoint inhibitors

Paraneoplastic neurological syndromes (PNSs) are rare complications of systemic cancers that can affect all parts of the central and/or peripheral nervous system. A body of experimental and clinical data has demonstrated that the pathogenesis of PNSs is immune-mediated. Nevertheless, the mechanisms leading to immune tolerance breakdown in these conditions remain to be elucidated. Despite their rarity, PNSs offer a unique perspective to understand the complex interplay between cancer immunity, effect of immune checkpoint inhibitors (ICIs), and mechanisms underlying the attack of neurons in antibody-mediated neurological disorders, with potentially relevant therapeutic implications. In particular, it is reported that ICI treatment can unleash PNSs and that the immunopathological features of PNS-related tumors are distinctive, showing prominent tumor-infiltrating lymphocytes and germinal center reactions. Intriguingly, similar pathological substrates have gained further attention as potential biomarkers of ICI-sensitivity and oncological prognosis. Moreover, the genetic analysis of PNS-associated tumors has revealed specific molecular signatures and mutations in genes encoding onconeural proteins, leading to the production of highly immunogenic neoantigens. Other than PNSs, autoimmune encephalitides (AEs) comprise a recently described group of disorders characterized by prominent neuropsychiatric symptoms, diverse antibody spectrum, and less tight association with cancer. Other triggering factors seem to be involved in AEs. Recent data have shed light on the importance of preceding infections (in particular, herpes simplex virus encephalitis) in inducing neurological autoimmune disorders in susceptible individuals (those with a selective deficiency in the innate immune system). In addition, in some AEs (e.g. LGI1-antibody encephalitis) an association with specific host-related factors [e.g., human leukocyte antigen (HLA)] was clearly demonstrated. We provide herein a comprehensive review of the most recent findings in the field of PNSs and AEs, with particular focus on their triggering factors and immunopathogenesis.

Precision health: A pragmatic approach to understanding and addressing key factors in autoimmune diseases

The past decade has witnessed a significant paradigm shift in the clinical approach to autoimmune diseases, lead primarily by initiatives in precision medicine, precision health and precision public health initiatives. An understanding and pragmatic implementation of these approaches require an understanding of the drivers, gaps and limitations of precision medicine. Gaining the trust of the public and patients is paramount but understanding that technologies such as artificial intelligences and machine learning still require context that can only be provided by human input or what is called augmented machine learning. The role of genomics, the microbiome and proteomics, such as autoantibody testing, requires continuing refinement through research and pragmatic approaches to their use in applied precision medicine.