Immunophenotype of blood lymphocytes in neuroblastoma-associated opsoclonus-myoclonus

Opsoclonus-myoclonus syndrome associated with neuroblastoma: Insights into antitumor immunity

Opsoclonus-myoclonus syndrome (OMS) is a rare neurological disorder. Half of these cases occur in children with neuroblastoma. Neuroblastoma patients with OMS usually have better oncological outcomes than those without OMS even after stratification by tumor stage and age, indicating that factors mediating OMS may also inhibit tumor cell proliferation. Although the mechanisms underlying OMS remain undefined, the cytokines and lymphocytes alterations in the cerebrospinal fluid support the concept that it is a pattern of neuroinflammation due to an autoimmune effect. The presence of lymphoid follicles consisting of follicular dendritic cells, CD20⁺ B lymphocytes, CD3⁺ T lymphocytes, and CD68⁺ macrophages in the tumor microenvironment in OMS-associated neuroblastoma support the autoimmune nature of this disorder. This review focuses on the clinical and genetic features of OMS-associated neuroblastoma, and we update readers on immune features of neuroblastoma with or without OMS to gain insights into antitumor immunity as it relates to tumor biology and prognosis.

Increased Prevalence of Familial Autoimmune Disease in Children With Opsoclonus-Myoclonus Syndrome

Background and Objectives

Opsoclonus-myoclonus syndrome (OMS) is a rare autoimmune disorder associated with neuroblastoma in children, although idiopathic and postinfectious etiologies are present in children and adults. Small cohort studies in homogenous populations have revealed elevated rates of autoimmunity in family members of patients with OMS, although no differentiation between paraneoplastic and nonparaneoplastic forms has been performed. The objective of this study was to investigate the prevalence of autoimmune disease in first-degree relatives of pediatric patients with paraneoplastic and nonparaneoplastic OMS.

Methods

A single-center cohort study of consecutively evaluated children with OMS was performed. Parents of patients were prospectively administered surveys on familial autoimmune disease. Rates of autoimmune disease in first-degree relatives of pediatric patients with OMS were compared using Fisher exact t test and χ² analysis: (1) between those with and without a paraneoplastic cause and (2) between healthy and disease (pediatric multiple sclerosis [MS]) controls from the United States Pediatric MS Network.

Results

Thirty-five patients (18 paraneoplastic, median age at onset 19.0 months; 17 idiopathic, median age at onset 25.0 months) and 68 first-degree relatives (median age 41.9 years) were enrolled. One patient developed systemic lupus erythematosus 7 years after OMS onset. Paraneoplastic OMS was associated with a 50% rate of autoimmune disease in a first-degree relative compared with 29% in idiopathic OMS (p = 0.31). The rate of first-degree relative autoimmune disease per OMS case (14/35, 40%) was higher than healthy controls (86/709, 12%; p < 0.001) and children with pediatric MS (101/495, 20%; p = 0.007).

Discussion

In a cohort of pediatric patients with OMS, there were elevated rates of first-degree relative autoimmune disease, with no difference in rates observed between paraneoplastic and idiopathic etiologies, suggesting an autoimmune genetic contribution to the development of OMS in children.

Effect of low-dose cyclophosphamide, ACTH, and IVIG combination immunotherapy on neuroinflammation in pediatric-onset OMS: A retrospective pilot study

INTRODUCTION

Flow cytometric cerebrospinal fluid (CSF) lymphocyte subset analysis has improved the diagnosis of neuroinflammation and identified multiple markers of inflammation in opsoclonus-myoclonus syndrome (OMS). The aim of this exploratory, retrospective study was to analyze the effect of immunotherapy on these markers to determine which agents are disease modifying.

METHODS

Cross-sectional immunological observations were made in an IRB-approved case-control study, and patients were treated empirically. Ten different CSF lymphocyte subpopulations from 18 children with persistent OMS had been measured by flow cytometry before and after clinical treatment with cyclophosphamide/ACTH/IVIG combination (n = 7) or ACTH/IVIG alone (n = 11). Clinical severity of OMS was scored from videotapes by a blinded observer using the OMS Evaluation Scale.

RESULTS

Only cyclophosphamide combination therapy (mean dose 26 ± 3 mg/kg or 922 ± 176 mg/m² x 6 cycles) significantly decreased the percentage of CSF B cells. The mean reduction was 65%, with CSF B cell frequency normalized at 7-8 months in 70%. Other abnormalities of the CSF immunophenotype, such as the low CD4/CD8 T cell ratio, persisted, and there were no therapeutic changes in T cell activation/maturation markers. Effects on relative and absolute size of PBMC subsets were similar. Clinical improvement was 70% and 55% in respective treatment groups. The relapse rates of the two groups did not significantly differ.

DISCUSSION

The main effect of cyclophosphamide combination therapy on neuroinflammation in OMS was moderate reduction in CSF B cell expansion. Though exploratory, it may provide a steroid sparer option in partially-responsive OMS.

Uncommon reasons of the digestive tract-related paraneoplastic syndromes in children with neuroblastic tumors: three case reports

Aim of the study

presentation of the uncommon paraneoplastic syndromes related to the gastrointestinal tract that may occur in children with neuroblastic tumors and their impact on the disease course.

Material and methods

Retrospective analysis of three cases of patients mainly with digestive tract-related symptoms, who were originally admitted to the gastroenterology department from 2013 to 2016 and were finally diagnosed with neuroblastic tumors.

Results

The clinical data analysis showed that the symptoms from gastrointestinal tract were dominant in analyzed subjects. The first case is a girl with weight loss, bloating and severe diarrhea, admitted to the hospital in a state of dehydration. The laboratory tests revealed severe hypokalemia. Finally, vasoactive intestinal peptide (VIP) secreting ganglioneuroblastoma was diagnosed and effective surgery was performed. The second case was also a girl who suffered from the incidents of watery diarrhea and flatulence. The tumor was detected by computerized tomography scan. The 3^rd stage of ganglioneuroblastoma was diagnosed. The patient required chemotherapy, radiotherapy and surgery treatment. The third child was a boy, hospitalized due to abdominal pain, constipation and weakness. During the diagnostic process, the 4^th stage of neuroblastoma was recognized. The chemotherapy, surgery, radiotherapy and immunotherapy were applied.

Conclusions

In children with common abdominal symptoms as chronic flatulence, diarrhea or severe constipation of unknown etiology, the neuroblastic tumors should be considered.

Cerebrospinal fluid γδ T cell frequency is age-related: a case-control study of 435 children with inflammatory and non-inflammatory neurological disorders

Studies of cerebrospinal fluid (CSF) γδ T cells in children are limited, due especially to the lack of control data. In adults, gamma/delta T cells (TCR-γδ) residing in the intrathecal space are sometimes involved in neuroinflammation. To evaluate the possible role of γδ T cells in paediatric neuroinflammation, we immunophenotyped cerebrospinal fluid (CSF) and blood lymphocytes using flow cytometry in a case-control study of 100 children with non-inflammatory neurological disorders (NIND), 312 with opsoclonus-myoclonus (OMS) and 23 with other inflammatory neurological disorders (OIND). In NIND, the negative correlation between CSF γδ T cell frequency and patient age was striking: median frequency of 27% in infants and 3·3% in teens. Interindividual variations were largest in the youngest. There was no gender effect. In all OMS, after correcting for age, only a small effect of OMS severity remained. Measurement of markers for γδ T cell activation [human leucocyte antigen D-related (HLA-DR)], maturation (CD45RA, CD45RO) or intracellular cytokine staining [interleukin (IL)-4, interferon (IFN)-γ] failed to discriminate OMS and NIND groups. Of seven OMS immunotherapies/combinations, none altered the frequency of total CSF γδ T cells or subsets significantly. In OIND, the CSF γδ T cell frequency was < 10% for single samples of other paraneoplastic disorders [anti-neuronal nuclear antibody (ANNA)-1, PCA-1, teratoma-associated syndrome], cerebellar ataxia (post-infectious, ataxia-telangiectasia), acute disseminated encephalomyelitis, neuroborreliosis and encephalitis. This study provides new insights into CSF γδ T cells in the paediatric population. Although their role in CSF remains elusive, the negative age correlation, resistance to immunotherapy and our age cut-off references for NIND are important findings for the design of future paediatric studies.

Demographic, Clinical, and Immunologic Features of 389 Children with Opsoclonus-Myoclonus Syndrome: A Cross-sectional Study

Pediatric-onset opsoclonus-myoclonus syndrome (OMS) is a devastating neuroinflammatory, often paraneoplastic, disorder. The objective was to characterize demographic, clinical, and immunologic aspects in the largest cohort reported to date. Cross-sectional data were collected on 389 children in an IRB-approved, observational study at the National Pediatric Myoclonus Center. Non-parametric statistical analysis was used. OMS manifested in major racial/ethnic groups, paralleling US population densities. Median onset age was 1.5 years (1.2–2 interquartile range), inclusive of infants (14%), toddlers (61%), and youngsters (25%). The higher female sex ratio of 1.2 was already evident in toddlers. Time to diagnosis was 1.2 months (0.7–3); to treatment, 1.4 months (0.4–4). Irritability/crying dominated prodromal symptomatology (60%); overt infections in <35%. Acute cerebellar ataxia was the most common misdiagnosis; staggering appeared earliest among 10 ranked neurological signs (P < 0.0001). Some untreated youngsters had no words (33%) or sentences (73%). Remote neuroblastic tumors were detected in 50%; resection was insufficient OMS treatment (58%). Age at tumor diagnosis related to tumor type (P = 0.004) and stage (P = 0.002). A novel observation was that paraneoplastic frequency varied with patient age—not a mere function of the frequency of neuroblastoma, which was lowest in the first 6 months of life, when that of neuroblastoma without OMS was highest. The cerebrospinal fluid (CSF) leukocyte count was minimally elevated in 14% (≤11/mm³) with normal differential, and commercially screened serum autoantibodies were negative, but CSF oligoclonal bands (OCB) and B cells frequency were positive (58 and 93%). Analysis of patients presenting on immunotherapy revealed a shift in physician treatment practice patterns from monotherapy toward multi-agent immunotherapy (P < 0.001); the number of agents/sequences varied. In sum, a major clinical challenge is to increase OMS recognition, prevent initial misdiagnosis, and shorten time to diagnosis/treatment. The index of suspicion for an underlying tumor must remain high despite symptoms of infection. The disparity in onset age of neuroblastoma frequency with that of neuroblastoma with OMS warrants further studies of potential host/tumor factors. OMS neuroinflammation is best diagnosed by CSF OCB and B cells, not by routine CSF or commercial antibody studies.

6-Mercaptopurine modifies cerebrospinal fluid T cell abnormalities in paediatric opsoclonus-myoclonus as steroid sparer

The purpose of this study was to evaluate the capacity of 6-mercaptopurine (6-MP), a known immunosuppressant, to normalize cerebrospinal fluid (CSF) lymphocyte frequencies in opsoclonus-myoclonus syndrome (OMS) and function as a steroid sparer. CSF and blood lymphocytes were immunophenotyped in 11 children with OMS (without CSF B cell expansion) using a comprehensive panel of cell surface adhesion, activation and maturation markers by flow cytometry, and referenced to 18 paediatric controls. Drug metabolites, lymphocyte counts and liver function tests were used clinically to monitoring therapeutic range and toxicity. In CSF, adjunctive oral 6-MP was associated with a 21% increase in the low percentage of CD4⁺ T cells in OMS, restoring the CD4/CD8 ratio. The percentage of CD4⁺ T cells that were interferon (IFN)-γ⁺ was reduced by 66%, shifting the cytokine balance away from T helper type 1 (Th1) (proinflammatory) predominance. The percentage of natural killer (NK) cells decreased significantly in CSF (-32%) and blood (-67 to -82%). Low blood absolute lymphocyte count was more predictive of improvement in CSF lymphocyte proportions (correlated with % CD4⁺ T cells) than the 6-thioguanine level (no correlation). 6-MP was difficult to titrate: 50% achieved the target absolute lymphocyte count (< 1·5 K/mm); 20%, the 'therapeutic' 6-thioguanine level; and 40% the non-toxic 6-methylmercaptopurine level. Side effects and transaminase elevation were mild and reversible. Clinical steroid-sparing properties and lowered relapse frequency were demonstrated. 6-MP displayed unique pharmacodynamic properties that may be useful in OMS and other autoimmune disorders. Its steroid sparer capacity is limited to children in whom the therapeutic window can be reached without limiting pharmacokinetic factors or side effects.

Cancer and Autoimmunity: Paraneoplastic Neurological Disorders Associated With Neuroblastic Tumors

Cancer and autoimmunity come together in paraneoplastic syndromes (PNS), which reflect the remote, not direct, effects of cancer. In the pediatric population, a variety of PNS have been described, but the most common of these rare disorders are instigated by neuroblastic tumors, such as neuroblastoma, ganglioneuroblastoma, and ganglioneuroma. The main pediatric-onset neurological PNS are ROHHAD syndrome, anti-ANNA1 (anti-Hu), and opsoclonus-myoclonus syndrome. They manifest distinctive neurological features, which aid the diagnosis, though under-recognition still poses serious challenges and risks. In each clinical syndrome, a large subgroup of patients had no demonstrated tumor. Most neurological PNS are immunologically mediated, and CSF neuroimmunological studies show common elements of immune involvement in PNS as well as important differences. Future immunotherapy strategies may be able to take advantage of these abnormalities.

Quantitative peripheral blood perturbations of γδ T cells in human disease and their clinical implications

Human γδ T cells, which play innate and adaptive, protective as well as destructive, roles in the immune response, were discovered in 1986, but the clinical significance of alterations of the levels of these cells in the peripheral blood in human diseases has not been comprehensively reviewed. Here, we review patterns of easily measurable changes of this subset of T cells in peripheral blood from relevant publications in PubMed and their correlations with specific disease categories, specific diagnoses within disease categories, and prognostic outcomes. These collective data suggest that enumeration of γδ T cells and their subsets in the peripheral blood of patients could be a useful tool to evaluate diagnosis and prognosis in the clinical setting.

Cerebellar and cortical abnormalities in paediatric opsoclonus-myoclonus syndrome

AIM

Paediatric opsoclonus-myoclonus syndrome (OMS) is a poorly understood condition with long-term cognitive, behavioural, and motor sequelae. Neuroimaging has indicated cerebellar atrophy in the chronic phase, but this alone may not explain the cognitive sequelae seen in many children with OMS. This study aimed to determine the extent of structural change throughout the brain that may underpin the range of clinical outcomes.

METHOD

Nine participants with OMS (one male, eight females; mean age [SD] 14y, [6y 5mo], range 12-30y) and 10 comparison individuals (three males, seven females; mean age 12y 6mo, [4y 9mo], range 10-23y) underwent magnetic resonance imaging to acquire T1-weighted structural images, diffusion-weighted images, and magnetic resonance spectroscopy scans. Neuroblastoma had been present in four participants with OMS. Voxel-based morphometry was used to determine changes in grey matter volume, tract-based spatial statistics to analyze white matter integrity, and Freesurfer to analyze cortical thickness across visual and motor cortices.

RESULTS

Whole-brain analysis indicated that cerebellar grey matter was significantly reduced in the patients with OMS, particularly in the vermis and flocculonodular lobe. A region-of-interest analysis indicated significantly lower cerebellar grey matter volume, particularly in patients with the greatest OMS scores. Diffusion-weighted images did not show effects at a whole brain level, but all major cerebellar tracts showed increased mean diffusivity when analysis was restricted to the cerebellum. Cortical thickness was reduced across the motor and visual areas in the OMS group, indicating involvement beyond the cerebellum.

INTERPRETATION

Across individuals with OMS, there is considerable cerebellar atrophy, particularly in the vermis and flocculonodular lobes with atrophy severity associated with persistent symptomatology. Differences in cerebral cortical thickness indicate disease effects beyond the cerebellum.

Proliferative response of peripheral blood mononuclear cells in anti-Hu antibody-associated patients with paraneoplastic neurological syndrome and their depressant effect on small cell lung cancer cells

Previous studies have suggested that common antigens that exist in neurons and tumor cells trigger cross immunoreaction, which attacks the neurons and tumor cells simultaneously. This action leads to paraneoplastic symptoms and slowed tumor growth. The present study co‑cultured peripheral blood mononuclear cells (PBMCs) from anti‑Hu antibody‑associated patients with paraneoplastic neurological syndrome (PNS) and the small cell lung cancer cell line NCI‑H446 (H446) in vitro. In the PNS group, no significant difference was observed in the proliferation index of PBMCs and H446 cells between the mixed or separate cultures. The proportion of CD4+ T cells in patients with PNS (76.54±3.96%) was significantly higher (P<0.05) compared with the healthy control individuals (51.75±17.3%). In conclusion, the sensitized specific T cells in the PBMCs of PNS patients predominantly comprised of CD4+ T cells, which had no inhibitory effect on small cell lung cancer cells in vitro.

Imbalance in circulating T lymphocyte subsets contributes to Hu antibody-associated paraneoplastic neurological syndromes

Paraneoplastic neurological syndromes (PNS) are associated with small cell lung cancer (SCLC) and Hu antibodies, which are considered to have an immune-mediated etiology. As a pathogenic role for Hu antibodies (Hu-Ab) in PNS could not be demonstrated, the cellular immune response against the Hu proteins has been further investigated. To delve deeper into the hypothesized cell-mediated immune pathogenesis of these syndromes, imbalances within circulating T lymphocyte subsets were investigated to determine their significance in Hu antibody-associated PNS. The circulating T lymphocyte subsets were analyzed in untreated patients with SCLC, PNS and Hu-Ab (n=10), SCLC without PNS (n=10) and healthy controls (n=12) using flow cytometry. Patients with PNS and SCLC, had a variety of changes within their circulating T lymphocyte subsets, which included; lymphopenia of the CD3(+)and CD4(+) T cells, increased proportions of total activated T cells and activated CD4(+) T cells, and reduced numbers of CD4(+) and CD25(+) regulatory T cells (Treg). These results suggest that the excessive activation of T cells and dysfunction of Treg contribute to Hu antibody-associated PNS.

Evaluation of the child with acute ataxia: a systematic review

Evaluation of acute ataxia in a child poses a dilemma for the clinician in determining the extent and timing of initial screening tests. This article reviews the evidence concerning the diagnostic yield of commonly ordered tests in evaluating the child with acute ataxia. The literature revealed the following frequencies of laboratory screening abnormalities in children with acute ataxia: CT (∼2.5%), MRI (∼5%), lumbar puncture (43%), EEG (42%), and toxicology (49%). In most studies, abnormalities detected by these screening tests were nondiagnostic. There are insufficient data to assess yields of testing for autoimmune disorders or inborn errors of metabolism. A toxicology screen should be considered in all children presenting with acute ataxia. Neuroimaging should be considered in all children with new onset ataxia. Cerebrospinal fluid analysis has limited diagnostic specificity unless clinically indicated. Studies to examine neurophysiology testing did have sufficient evidence to support their use. There is insufficient evidence to establish a role for autoantibody testing or for routine screening for inborn error of metabolism in children presenting with acute ataxia. Finally, in a child presenting with ataxia and opsoclonus myoclonus, urine catecholamine testing for occult neuroblastoma is recommended. Nuclear scan may be considered, however, there is insufficient evidence for additional body imaging.

Another promising treatment option for neuroblastoma-associated opsoclonus-myoclonus syndrome by oral high-dose dexamethasone pulse: lymphocyte markers as disease activity

A one-year-old boy with neuroblastoma (NBoma)-associated opsoclonus-myoclonus syndrome (OMS) was treated by oral high-dose dexamethasone (DEX) pulses (20 mg/m(2)/day of DEX for three consecutive days) every 28 days for 6 months after resection of the tumor. All OMS symptoms improved after the first course of DEX pulse therapy and disappeared after the last course. No adverse effects were observed. Minor deterioration of his developmental quotient was noted 33 months after the onset of the disease. NBoma remission has been maintained since treatment. Before DEX pulse therapy, frequency of T lymphocyte, in particular CD4-positive cell decreased markedly resulted in low CD4/8 ratio in the peripheral blood (PB). The frequency of B lymphocyte increased, especially in cerebrospinal fluid. These aberrant values in PB were reversed by DEX pulse therapy and correlated well with the neurological symptoms. A prospective study that assesses the efficacy of this promising and inexpensive treatment for OMS is warranted.

Mycoplasma pneumoniae associated opsoclonus-myoclonus syndrome in three cases

Opsoclonus-myoclonus syndrome (OMS) is a rare acquired movement disorder occurring in all age groups, predominantly in infants. Although the exact pathogenesis is still undefined, there is strong evidence for a paraneoplastic or parainfectious immune process resulting in central nervous system dysfunction. Mycoplasma pneumoniae has been implicated in a number of immune-mediated neurologic diseases [28]. However, the association of M. pneumoniae and opsoclonus-myoclonus-ataxia syndrome is not well established so far. We present three cases with opsoclonus-myoclonus-ataxia syndrome in adolescents following an infection with M. pneumoniae. Monophasic disease course and full recovery correspond to the favorable prognosis known from parainfectious cases in young adults. This should affect therapeutic consideration. OMS should be added to the spectrum of M. pneumoniae-associated neurologic complications. Nevertheless, neuroblastoma has to be ruled out in all cases of OMS.

Insights on chronic-relapsing opsoclonus-myoclonus from a pilot study of mycophenolate mofetil

Opsoclonus-myoclonus syndrome is characterized by abnormal lymphocyte trafficking into brain. The authors hypothesized that mycophenolate mofetil, a lymphocyte proliferation inhibitor, might be therapeutic. The cerebrospinal fluid and blood immunophenotypes of 15 children with predominantly chronic-relapsing opsoclonus-myoclonus syndrome were compared before and after treatment by flow cytometry. Mycophenolate mofetil reduced the cerebrospinal fluid expansion of HLA-DR+ activated T cells (-40%); the frequency of other T-cell or natural killer cell subsets remained unchanged, but cerebrospinal fluid B cells increased significantly. Adrenocorticotropic hormone dose was lowered by 64% over an average of 1.5 years, yet 73% eventually relapsed despite therapeutic drug levels. Prior treatment with rituximab prevented relapse-associated increase in cerebrospinal fluid B cells, without hindering mycophenolate mofetil-induced reduction in T-cell activation. These data demonstrate resistant immunologic problems in chronic-relapsing opsoclonus-myoclonus syndrome. Mycophenolate mofetil did not prevent relapse. The novel effect of mycophenolate mofetil on chronically activated T cells may contribute to its efficacy in T-cell mediated neurological disorders.

Imbalances in circulating lymphocyte subsets in Hu antibody associated paraneoplastic neurological syndromes

In paraneoplastic neurological syndromes (PNS) associated with small cell lung cancer (SCLC) and Hu antibodies, neuron-specific Hu antigens expressed by the tumour hypothetically trigger an immune response that cross-reacts with Hu antigens in the nervous system, resulting in tumour suppression and neuronal damage. To gain more insight into the hypothesized cell-mediated immune pathogenesis of these syndromes, we analysed the circulating lymphocyte subsets in untreated patients with SCLC, PNS and Hu antibodies (n = 18), SCLC without PNS (n = 19) and controls (n = 29) using flow cytometry. SCLC patients with PNS had a variety of imbalances within their circulating lymphocyte subsets as compared with SCLC patients without PNS and healthy controls: (i) a lymphopenia of the major subsets (i.e. B, CD4+ and CD8+ T lymphocytes); (ii) increased proportions of activated CD4+ and CD8+ T cells; (iii) reduced numbers of terminally differentiated effector CD8+ T cells and cells with a cytotoxic T-cell phenotype (CD56+ and CD57+). Although indirect, our data provide further support for the involvement of T cells in the pathogenesis of Hu antibody associated PNS.

T-lymphocyte production, function, and death in children who recovered from opsoclonus-myoclonus syndrome

Reduced CD4+ lymphocytes have been recently found in peripheral blood of children with active opsoclonus-myoclonus syndrome. The authors identified 2 children who recovered from this syndrome, one of whom showed reduced CD4+ lymphocytes 2 years after the disease onset. Except for a decrease of "naive" CD45RA+ CD4+ population and a mild restriction of T-cell heterogeneity in this patient, probably related to the immune response to viral infections, no alterations of T-cell homeostasis and function were found in either child. Therefore, the decrease of CD4+ cells may persist after clinical recovery, but the causes of this abnormality cannot be ascribed to intrinsic T-cell defects.