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Background and purpose: Paraneoplastic neurological autoimmunity is well described with small‐cell lung cancer, but information is limited for other neuroendocrine neoplasms (NENs). Methods: Adult patients with histopathologically confirmed non‐pulmonary NENs, neurological autoimmunity within 5 years of NEN diagnosis, and neural antibody testing performed at the Mayo Clinic Neuroimmunology Laboratory (January 2008 to March 2023) were retrospectively identified. Control sera were available from patients with NENs without neurological autoimmunity (116). Results: Thirty‐four patients were identified (median age 68 years, range 31–87). The most common primary tumor sites were pancreas (nine), skin (Merkel cell, eight), small bowel/duodenum (seven), and unknown (seven). Five patients received immune checkpoint inhibitor (ICI) therapy before symptom onset; symptoms preceded cancer diagnosis in 62.1% of non‐ICI‐treated patients. The most frequent neurological phenotypes (non‐ICI‐treated) were movement disorders (12; cerebellar ataxia in 10), dysautonomia (six), peripheral neuropathy (eight), encephalitis (four), and neuromuscular junction disorders (four). Neural antibodies were detected in 55.9% of patients studied (most common specificities: P/Q‐type voltage‐gated calcium channel [seven], muscle‐type acetylcholine receptor [three], anti‐neuronal nuclear antibody type 1 [three], and neuronal intermediate filaments [two]), but in only 6.9% of controls. Amongst patients receiving cancer or immunosuppressive therapy, 51.6% had partial or complete recovery. Outcomes were unfavorable in 48.3% (non‐ICI‐treated) and neural autoantibody positivity was associated with poor neurological outcome. Discussion: Neurological autoimmunity associated with non‐pulmonary NENs is often multifocal and can be treatment responsive, underscoring the importance of rapid recognition and early treatment. [ABSTRACT FROM AUTHOR]

Abstract Background Paraneoplastic neurological syndromes (PNS) are a group of syndromes that affect the central and peripheral neuromuscular system in association with cancer. Specific antibodies may assist in the diagnosis of PNS. The antibodies tested can be classified into those directed against intracellular neuronal proteins ("well characterized" PNS: Hu, Yo, RI, CV2, amphiphysin, Ma1, Ma2) and those directed against neural surface antigens (autoimmune encephalitis syndromes: NMDA, AMPA, LGI1, CASPR2, GABAR). We aimed to characterize patients with unexplained neuropsychiatric symptoms, in whom positive PNS antibodies were detected in the Sheba medical center, a large referral hospital. Methods Clinical and demographic data of patients with positive PNS antibodies were collected during the years 2002–2016. Antibodies were tested by either Line immunoassay or by cell-based indirect immunofluorscent assay. Results During the follow up of 14 years, 4010 PNS tests were performed in patients with unexplained neuropsychiatric symptoms. Seventy-two were found to be positive; among them we had full clinical data access to 44. The most frequent antibodies were anti-Hu (31.8%), anti-Yo (18.2%), anti-CV2 (13.6%), and anti-NMDA (9.1%), and the most common cancers were small-cell lung (SCLC) and ovarian cancers. In the well characterized paraneoplastic group, cancer was diagnosed in 55.9% of the patients, and in the autoimmune encephalitis group, 40.0% were diagnosed with cancer. A positive correlation between antibody titer and the presence of cancer was found. Ninety percent of the tests in patients who were found positive were ordered by a neurologist or neuro-oncologist. Conclusions The titers of PNS auto-antibodies can predict cancer in patients whom anti-PNS antibodies are tested. In addition, consultation with a specialist should be considered before this test is ordered. [ABSTRACT FROM AUTHOR]

Autoantibodies are important in the diagnosis of dermatomyositis. They can be divided in two different groups: myositis-associated autoantibodies (MAA) prevailing in overlap syndromes, and myositis-specific autoantibodies (MSA), with diagnostic specificity exceeding 90%. Our purpose was to detect retrospectively the prevalence of the most common MSAs in a group of 19 adult DM patients (13 women, 6 men). A severe DM (SDM), with extensive cutaneous and muscular manifestations, dysphagia, and sometimes pneumopathy, was detected in ten cases. Three patients had a mild DM (MDM), with little muscle and skin impairment, and a short course. Four patients suffered from amyopathic DM (ADM), two from paraneoplastic DM (PDM). Each serum was tested for ANA, ENA, MAAs, MSAs. Myositis-specific autoantibodies were detected in 15 cases. The most frequent was anti-TIF1γ, associated with SDM or PDM in four out of seven cases. Anti-MDA5 antibodies were recorded in a SDM and in a ADM with lung fibrosis. Anti-Mi2 and anti-SRP antibodies were both detected in a MDM and in a SDM, whereas anti-SAE1 in a amyopathic form. Other antibodies (anti-NXP2, -Jo1, -PL7, -PL12, -OJ) were found in single patients with SDM. Our series confirmed that specific autoantibodies could be helpful to classify different clinical subsets, particularly in the case of paraneoplastic forms or association with pneumopathy. Moreover, they can help in predicting the disease evolution and influence therapeutic strategies. A greater number of cases should be useful to highlight the clinical and pathogenic role of these antibodies, and develop a homogeneous protocol for diagnosis and treatment. [ABSTRACT FROM AUTHOR]

Recoverin-antibody-related disease is currently restricted to late-onset ataxia and autoimmune retinopathy, which can be paraneoplastic or not. However, cognitive dysfunction associated with recoverin antibodies has not been reported so far in a homogeneous patient group. Our case series is dedicated to describing the novel phenotype of cognitive impairment associated with recoverin antibodies. We included five patients with cognitive impairment who presented serum recoverin autoantibodies detected by immunoblots in our case series investigation. We also analyzed their psychopathology, clinical data, cerebrospinal fluid (CSF), and neuroimaging data. Five patients with cognitive impairment associated with serum recoverin antibodies exhibited profound dysfunctional learning and verbal memory. In the CSF of 40% of them, we also diagnosed axonal neurodegeneration entailing elevated tau and phosphorylated tau protein levels. Psychopathologies such as affective symptoms (restlessness, depressive mood, anxiety, complaintiveness) and formal thought disorder, such as rumination, were detected in 25–75% of the patients. We hypothesized a role of recoverin autoimmunity in the pineal gland involving consecutive modulation of hippocampus-based memory caused by an altered release of melatonin. We describe a novel phenotype of possible recoverin autoimmunity in patients with cognitive impairment. However, no clear diagnostic clues can be extracted because of the low diagnostic validity of the testing strategies applied. The possibility of recoverin antibody autoimmunity in the pineal gland correlating with a modulation of hippocampus-based memory should be further investigated. [ABSTRACT FROM AUTHOR]

Background: Our goal is to investigate the serum profile of neural autoantibodies in community-based patients with irritable bowel syndrome (IBS) or functional dyspepsia. The pathogenesis of functional gastrointestinal (GI) disorders, including IBS and dyspepsia, are unknown. Theories range from purely psychological to autoimmune alterations in GI tract neuromuscular function.Methods: The study subjects, based in Olmsted County, MN, reported symptoms of functional dyspepsia or IBS (n = 69), or were asymptomatic controls (n = 64). Their coded sera were screened for antibodies targeting neuronal, glial, and muscle autoantigens.Results: The prevalence of neural autoantibodies with functional GI disorders did not differ significantly from controls (17% vs. 13%; P = 0.43). In no case was a neuronal or glial nuclear autoantibody or enteric neuronal autoantibody identified. Neuronal cation channel antibodies were identified in 9% of cases (voltage-gated potassium channel [VGKC] in one dyspepsia case and one IBS case, ganglionic acetylcholine receptor [AChR] in four IBS cases) and in 6% of controls (ganglionic AChR in one, voltage-gated calcium channel [VGCC], N-type, in two and VGKC in one; P = 0.36). The frequency of glutamic acid decarboxylase-65 (GAD65) autoantibodies was similar in cases (10%) and controls (5%; P = 0.23).Conclusions: Our data do not support neural autoimmunity as the basis for most IBS or functional dyspepsia cases. [ABSTRACT FROM AUTHOR]

The article discusses a study of the autoimmune system and the role it can play in behavioral abnormalities. It states that a growing number of psychiatric disorders can be related to physiological reasons, the best example being how antibody-mediatic limbic encephalitis can result in psychological changes. In such cases, autoantibodies affect neuronal functions, which in turn affect thinking and behavior. The study focuses on autoimmune encephalopathies, which include paraneoplastic disorders, nonparaneoplastic limbic encephalitis and others.

Abstract: Childhood opsoclonus-myoclonus syndrome (OMS) occurs idiopathic or, in association with a neuroblastoma, as a paraneoplastic syndrome. Since autoantibodies were identified in some patients, an autoimmune pathogenesis has been suspected. While the newly discovered B-cell activating factors BAFF and APRIL are involved in systemic autoimmune diseases, their association with neuroimmunological diseases is hardly understood. We here investigated the BAFF and APRIL levels in serum and cerebrospinal fluid (CSF) of OMS patients and their correlation with surface-binding autoantibodies. BAFF and APRIL were both determined by ELISA, and autoantibodies to cerebellar granular neurons (CGN) have been investigated by flow cytometry in 17 OMS patients, 16 neuroblastoma (NB) patients, 13 controls and 11 children with inflammatory neurological diseases (IND). BAFF, but no APRIL, was elevated in the CSF of OMS children and IND children. However, in contrast to IND patients, OMS patients did not have a blood–brain-barrier disturbance, indicating that BAFF was produced intrathecally in OMS patients, but not in IND patients. CSF BAFF levels showed a correlation with CSF CGN autoantibodies (r 2 =0.58, p <0.05). These data indicate that an activated B-cell system in the cerebrospinal fluid is involved in the pathogenesis of OMS, and BAFF may be a candidate parameter for the activation of B-cell immune system. [Copyright &y& Elsevier]

We report on a case of paraneoplastic pemphigus associated with Castleman's disease. Clinical pathologic features were not conclusive. Diagnosis was established thanks to the detection of seric autoantibodies directed against intercellular substance by indirect immunofluorescence on monkey esophagus. The positive result of this test prompted us to reevaluate the patient and to detect the occult neoplasia. The demonstration of autoantibodies against plakins is the key marker of this disease but depends on tests that may not be readily available in many places like immunoprecipitation, immunoblotting, or indirect immunofluorescence over rat bladder. In this setting, tests like indirect immunofluorescence over monkey esophagus, although unspecific, may aid in reaching the appropriate diagnosis. This case illustrates the importance of the laboratory of autoimmunity in the diagnosis of this type of pemphigus. [ABSTRACT FROM AUTHOR]

Abstract: Paraneoplastic cerebellar degeneration (PCD) is a potent autoimmune disorder in which antigen-driven responses toward the onconeural antigen are assumed to occur in patients. Yeast cell wall has adjuvant capacity and provides immunostimulatory effects of the antigen expressing in viable cells. The recombinant yeast expressing the PCD-associated antigen may become an immunogen for inducing PCD-associated autoimmunity in mice. We attempted to induce autoimmune responses with whole recombinant yeast expressing PCD-associated antigen. SJL/J strain of mouse is found to be a responder to the major epitope on the antigen for anti-Purkinje cell antibodies, and whole recombinant yeast could induce cellular and humoral autoimmune responses in vivo ion SJL/J mice. The immunization technique based on the recombinant yeast expressing a PCD-associated antigen provides a new tool for analyzing the underlying immunological pathomechanisms of PCD. [Copyright &y& Elsevier]

Paraneoplastic pemphigus (PNP) is an autoimmune blistering disease that occurs in association with underlying neoplasms. PNP patients develop characteristic autoantibodies directed against multiple antigens, mostly identified as members of the plakin family of cytoplasmic proteins (desmoplakin I and II, bullous pemphigoid antigen I, envoplakin, and periplakin). HD1/plectin, another member of the plakin family, has not previously been detected in the characteristic PNP antigen complex, which may relate to practical difficulties associated with its large size (molecular weight ≈ 500 kDa). In this study, a combination of immunoprecipitation and immunoblot is used to demonstrate that HD1/plectin is also recognized by sera from PNP patients. Thirteen of 16 PNP sera tested were positive for HD1/plectin compared with none of 43 control sera (11 pemphigus vulgaris, 11 pemphigus foliaceus, 11 bullous pemphigoid, and 10 normal individuals). Combined with our recent finding that desmoglein 3 and desmoglein 1 are cell surface target antigens in PNP, this demonstration of plectin/HD1 as another component of the antigen complex in PNP confirms that PNP is an autoimmune disease against desmoglein and plakin family molecules. [ABSTRACT FROM AUTHOR]

Paraneoplastic neurological syndromes (PNS) are immune-mediated diseases that occur in patients with tumors and can be associated with onconeural antibodies. Our aim was to describe our cohort of patients with PNS. Retrospective analysis of a cohort of patients followed in a Portuguese tertiary center, with autoantibodies against intracellular antigens from our PNS panel, between 2012 and 2017. Among the 882 patients with suspected PNS (1029 samples), 37 (4.2%) had positive and 27 (3.1%) weak positive antibodies. A total of 17 (29.3%) PNS were diagnosed, 5 were classic syndromes. Autoantibodies found were anti-Yo, anti-Hu, anti-titin, anti-Ma2, anti-SOX1, anti-Ri and anti-CV2/CRMP5. They were associated with thymoma, breast, colon, parotid gland and lung (small-cell, neuroendocrine or carcinoid) cancer. Among the 17 PNS patients, no tumor was found in 4 (mean follow-up of 46 months); no patients improved with tumor treatment, while 8 improved with immunotherapy; ten patients (59%) died during follow-up. Twenty (60.6%) patients with positive antibodies and 21 (84.0%) with weak positive were not diagnosed with a PNS. PNS had highly heterogenous clinical presentations. Response to tumor treatment was overall poor, with an unfavorable prognosis. In our cohort, only 29.3% of the patients with positive antibodies were diagnosed with a PNS. • Paraneoplastic neurological syndromes occur in patients with tumors and can be associated with onconeural antibodies. • The clinical presentation is highly heterogenous, with a recognized unfavorable prognosis. • The high rate of false-positive antibodies is a growing problem, particularly to smaller laboratories. [ABSTRACT FROM AUTHOR]

Abstract: Objective: To report clinical and pathological findings of a patient with late onset insulin-dependent diabetes mellitus (IDDM), progressive cerebellar ataxia (PCA) and hepatocellular carcinoma (HCC). Patient: A 64-year-old woman, with a long lasting IDDM, progressively developed a severe cerebellar syndrome and died 2years after the onset of the symptoms for a systemic infection. Autoantibodies to antigastric parietal cell and anti-pancreatic islet cell resulted positive. Autopsy showed a selective loss of Purkinje cells in the cerebellum, with an increase of Bergmann glia and variable microglial proliferation; furthermore, it disclosed an HCC. GAD-Abs were detected both in serum and CSF. Conclusions: Clinical and experimental reports suggest a possible role of neoplastic cells in producing GAD-Abs. We postulate, in our case, that HCC could have been responsible for an overproduction of GAD-Abs, leading to the onset of PCA. Thus, GAD-Abs could be considered as a paraneoplastic marker in a subgroup of patients with PCA. [Copyright &y& Elsevier]

We report a female patient with small cell lung cancer (SCLC) and clinical findings consistent with polyglandular autoimmune syndrome type 2 (PGA2) and paraneoplastic neurological syndrome (PNS). To the best of our knowledge, this is the first reported case of SCLC associated with PGA2 and PNS. All of the autoantibodies detected before anticancer treatment decreased below the upper normal limits after serial treatment, and the patients clinical symptoms also improved. Cross reactivity of autoantibodies may have contributed to the complicated clinical picture of this patient. [ABSTRACT FROM AUTHOR]