Anti-neurofilament protein antibodies in 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.

Update on opsoclonus-myoclonus syndrome in adults

Opsoclonus-myoclonus syndrome in adults is a rare and heterogeneous disorder with the clinical features of opsoclonus, myoclonus, ataxia, and behavioral and sleep disturbances. The pathophysiology is thought to be immunological on the basis of paraneoplastic or infectious etiologies. Immunomodulatory therapies should be performed although the response may be incomplete. A number of autoantibodies have been identified against a variety of antigens, but no diagnostic immunological marker has yet been identified. This review focuses on underlying mechanisms of opsoclonus-myoclonus syndrome, including findings that have been identified recently, and provides an update on the clinical features and treatments of this condition.

Genomic Profiles of Neuroblastoma Associated With Opsoclonus Myoclonus Syndrome

Opsoclonus myoclonus syndrome (OMS), often called "dancing eyed syndrome," is a rare neurological condition associated with neuroblastoma in the majority of all childhood cases. Genomic copy number profiles have shown to be of prognostic significance for neuroblastoma patients. The aim of this retrospective multicenter study was to analyze the genomic copy number profiles of tumors from children with neuroblastoma presenting with OMS at diagnosis. In 44 cases of neuroblastoma associated with OMS, overall genomic profiling by either array-comparative genomic hybridization or single nucleotide polymorphism array proved successful in 91% of the cases, distinguishing tumors harboring segmental chromosome alterations from those with numerical chromosome alterations only. A total of 23/44 (52%) tumors showed an segmental chromosome alterations genomic profile, 16/44 (36%) an numerical chromosome alterations genomic profile, and 1 case displayed an atypical profile (12q amplicon). No recurrently small interstitial copy number alterations were identified. With no tumor relapse nor disease-related deaths, the overall genomic profile was not of prognostic impact with regard to the oncological outcome in this series of patients. Thus, the observation of an excellent oncological outcome, even for those with an unfavorable genomic profile of neuroblastoma, supports the hypothesis that an immune response might be involved in tumor control in these patients with OMS.

Clinicopathological features of neuroblastic tumors with opsoclonus-myoclonus-ataxia syndrome: Follicular structure predicts a better neurological outcome

Neuroblastic tumors (NT) with opsoclonus-myoclonus syndrome (OMS) display characteristic histological features, such as lymphocytic infiltration with lymphoid follicles, indicating an underlying immune response. We retrospectively assessed NT patients from 2001 to 2016. Five cases of NT with OMS and 76 cases of NT without OMS were histopathologically reviewed in this study. The grade of lymphocytic infiltration was evaluated. The number of follicles was counted and the presence or absence of lymphoid follicles was recorded for each case. We also confirmed the presence or absence of follicular dendritic cells (FDCs). We investigated the relationship between the histopathological and clinical findings of NT with OMS. Lymphocytic infiltration was observed in all cases; however, the precise follicular structure was occasionally unclear. Patients with clear follicular structures displayed germinal centers including tingible body macrophages and FDCs. All patients without neurological sequelae demonstrated a clear follicular structure with a FDC meshwork pattern. The interval between OMS onset and the detection and initial treatment of NT was typically longer in patients with neurological sequelae compared to those without neurological sequelae. Early detection and treatment of NT with OMS at the phase of a clear follicular formation with multiple FDC may provide favorable neurological outcomes.

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.

Antibodies to dendritic neuronal surface antigens in opsoclonus myoclonus ataxia syndrome

Opsoclonus myoclonus ataxia syndrome (OMAS) is an autoimmune disorder characterized by rapid, random, conjugate eye movements (opsoclonus), myoclonus, and ataxia. Given these symptoms, autoantibodies targeting the cerebellum or brainstem could mediate the disease or be markers of autoimmunity. In a subset of patients with OMAS, we identified such autoantibodies, which bind to non-synaptic puncta on the surface of live cultured cerebellar and brainstem neuronal dendrites. These findings implicate autoimmunity to a neuronal surface antigen in the pathophysiology of OMAS. Identification of the targeted antigen(s) could elucidate the mechanisms underlying OMAS and provide a biomarker for diagnosis and response to therapy.

Adult-onset opsoclonus-myoclonus-ataxia syndrome as a manifestation of brazilian lyme disease-like syndrome: a case report and review of literature

Described in 1962, the opsoclonus-myoclonus-ataxia syndrome (OMAS) is a rare, neurologically debilitating disorder with distinct characteristics that may begin in childhood or adult life. Although many cases remain without etiological diagnosis, others are related to neoplasms and infectious diseases. We report a 41-year-old previously healthy male with an 8-day history of headache, vertigo, nausea, vomiting, and nystagmus. After a normal brain computed tomography and lymphocytic pleocytosis in cerebral spinal fluid (CSF), intravenous acyclovir therapy was initiated in the emergency room. On the third day of hospitalization, the diagnosis of OMAS was made based on the presence of chaotic and irregular eye movements, dysarthric speech, gait instability, generalized tremor, and myoclonic jerks. In the face of his neurological worsening, ampicillin followed by nonspecific immunotherapy (methylprednisolone and intravenous immunoglobulin) was prescribed, with mild clinical improvement. After a thorough laboratory workup, the definite diagnosis of neuroborreliosis was established and ceftriaxone (4 g/daily/3 wks) and doxycycline (200 mg/day/2 mo) was administered. Toward the end of the ceftriaxone regimen, the neurologic signs substantially improved. We believe this to be the first case description of OMAS as clinical presentation of Brazilian Lyme disease-like syndrome (Baggio-Yoshinari syndrome).

Paraneoplastic disorders of the central and peripheral nervous systems

Paraneoplatic neurologic syndromes (PNS) have been seminally defined as acute or subacute neurological syndromes resulting from nervous system dysfunction that is remote from the site of a malignant neoplasm or its metastases. However, in respect to our current understanding of their pathogenesis we may redefine these disorders as cancer-related dysimmune neurologic syndromes. We first deal with the epidemiology and the pathogenesis of PNS, then the different classic PNS are reviewed with clinical features according to the associated onconeuronal antibodies. Finally, therapeutic approaches are discussed.

Role of BAFF in Opsoclonus-Myoclonus syndrome, a bridge between cancer and autoimmunity

OMS is a rare paraneoplastic disorder that affects adults and children. Pediatric OMS is often associated with NB, a common, solid tumor of childhood, derived from the sympathetic nervous system. The detection of autoantibodies and lymphocytic infiltration in NB patients led to advance an autoimmune hypothesis for the pathogenesis of OMS-related NB. BAFF is a potent modulator of B cell growth and survival upon interaction with its receptors BAFF-R and BCMA. The aim of this study was to investigate mechanism(s) involved in ectopic lymphoid neogenesis in OMS-associated NB. We investigated BAFF, BAFF-R, and BCMA expression in NB tumors associated or not with OMS. Furthermore, we evaluated BAFF expression and secretion in NB cell lines, treated or untreated with differentiating agents. Immunohistochemically, lymphocytes infiltrating NB tumors from patients, with or without OMS, expressed BAFF, BAFF-R, and BCMA, whereas neuroblasts expressed BAFF and BCMA but not BAFF-R. By flow cytometry, BAFF was found to be consistently expressed in NB cell lines. Similarly to the results obtained in tissue lesions, BCMA but not BAFF-R was detected on the surface of all NB cell lines under basal conditions. De novo synthesis of BAFF-R and up-regulation of BCMA were observed in NB cell lines upon treatment with IFN-γ or 13-cis retinoic acid. This study provides new insights in the mechanisms driving the neogenesis of lymphoid follicles and in the functional interactions between tumor and immune cells in OMS-associated NB.

Immunological mechanisms in opsoclonus-myoclonus associated neuroblastoma

Opsoclonus-myoclonus syndrome is a rare paraneoplastic disorder, often associated with malignancies including neuroblastoma (NB), the most common solid tumor of childhood derived from the sympathetic nervous system. The pathogenesis of this syndrome is still undefined but is suspected to be the result of an autoimmune response. In this respect, different autoantibodies binding to neurons or cerebellar Purkinje cells have been detected in OMS-associated NB. In addition, immunohistochemical analysis of NB affecting children with OMS demonstrated the presence of interstitial or perivascular lymphoid infiltrates resembling secondary lymphoid follicles. Immunophenotyping of these lymphoid cells showed the existence of a mesh of CD21(+) follicular dendritic cells, numerous CD20(+) B lymphocytes in the germinal center and the mantle zone of the follicle and few CD3(+) T lymphocytes in a perifollicular area. Since information is lacking about the mechanism involved in ectopic lymphoid neogenesis of OMS-associated NB, we are currently investigating the role of different chemokines and their cognate receptors in the recruitment of lymphoid cells within tumor mass of OMS-associated NB. Here, we review some recent data about the pathogenesis of OMS-associated with NB.

Long-term survival in paraneoplastic opsoclonus-myoclonus syndrome associated with small cell lung cancer

Paraneoplastic opsoclonus-myoclonus syndrome (OMS) is associated with small cell lung cancer (SCLC) in adults. Without appropriate treatment for SCLC, all reported patients with SCLC and OMS have died of complications of OMS within 3 months of diagnosis. With appropriate treatment, about half of reported patients have had improvement in neurologic function, and several have become long-term survivors (6-84 months). We report a patient with SCLC who presented with OMS and was refractory to immunosuppressive therapy but responded rapidly to antineoplastic therapy and remains alive with no sign of SCLC recurrence and minimal residual neurologic deficits 30 months after diagnosis. In patients presenting with OMS, early recognition and treatment of the underlying malignancy probably improve the chances for recovery from the OMS with minimal deficit and ultimate survival.

New autoantibodies in pediatric opsoclonus myoclonus syndrome

Opsoclonus-myoclonus syndrome (OMS) is a rare neurologic disorder comprising the main symptoms of eye-movement disturbances, muscle jerks, and severe ataxia. In children and adults, some cases are associated with a tumor as a paraneoplastic syndrome, whereas in children the paraneoplastic form is almost exclusively associated with neuroblastoma. The detection of autoantibodies in some OMS sera led to the hypothesis that the syndrome is of autoimmune origin. Beside autoantibodies against intracellular proteins, such as anti-Hu, alpha-enolase, and KHSRP, specific binding of autoantibodies to the surface of neuroblastoma cells and cerebellar granular neurons have been found. Antiproliferative and proapoptotic effects of these autoantibodies on neuroblastoma cell lines were noted as well. These results support the concept of a humoral autoimmune process in the pathogenesis of OMS.

An update on opsoclonus

PURPOSE OF REVIEW

The aim of this article is to review opsoclonus, with particular emphasis on its immunopathogenesis and pathophysiology.

RECENT FINDINGS

Infections (West Nile virus, Lyme disease), neoplasms (non-Hodgkin's lymphoma, renal adenocarcinoma), celiac disease, and allogeneic hematopoietic stem cell transplantation can cause opsoclonus. Newly identified autoantibodies include antineuroleukin, antigliadin, antiendomysial, and anti-CV2. Evidence suggests that the autoantigens of opsoclonus reside in postsynaptic density, or on the cell surface of neurons or neuroblastoma cells (where they exert antiproliferative and proapoptotic effects). Most patients, however, are seronegative for autoantibodies. Cell-mediated immunity may also play a role, with B and T-cell recruitment in the cerebrospinal fluid linked to neurological signs. Rituximab, an anti-CD20 monoclonal antibody, seems efficacious as an adjunctive therapy. Although changes in synaptic weighting of saccadic burst neuron circuits in the brainstem have been implicated, disinhibition of the fastigial nucleus in the cerebellum, or damage to afferent projections to the fastigial nucleus, is a more plausible pathophysiologic mechanism which is supported by functional magnetic resonance imaging findings in patients.

SUMMARY

There is increasing recognition that both humoral and cell mediated immune mechanisms are involved in the pathogenesis of opsoclonus. Further studies are needed to further elucidate its immunopathogenesis and pathophysiology in order to develop novel and efficacious therapy.

Brain-derived neurotrophic factor and autoantibodies to neural antigens in sera of children with autistic spectrum disorders, Landau-Kleffner syndrome, and epilepsy

BACKGROUND

Brain derived neurotrophic factor (BDNF) elevation in newborn sera predicts intellectual/social developmental abnormalities. Other autoantibodies (AAs) to endothelial cells (ECs) and myelin basic protein (MBP) are also elevated in some children. We tested relationships between BDNF, BDNF AAs, and other AAs in children with these disorders.

METHODS

BDNF levels and IgG/IgM autoantibodies to BDNF, ECs, MBP, and histones were measured in children with autism, childhood disintegrative disorder (CDD), pervasive developmental delay-not otherwise specified (PDD-nos), acquired epilepsy, Landau-Kleffner syndrome (LKS); healthy children (HC), and children with non-neurological illnesses (NNI).

RESULTS

Mean BDNF levels were elevated in children with autism and CDD, (p < or = 0.0002) compared to HC or NNI. Mean IgG and IgM BDNF AAs were elevated in children with autism, CDD and epilepsy (p < or = 0.0005) compared to HC but not to NNI. Mean IgM AA EC titers detected by immunocytochemistry were higher in autism, PDD-NOS, epilepsy, and LKS (p < or = 0.005) compared to HC and NNI. While mean ELISA IgG EC AAs were higher in autism and PPD-NOS (p < 0.005) compared to HC but not NNI, ELISA IgM EC AAs were higher in children with autism, CDD, PDD-NOS, and epilepsy compared to both HC and NNI (p < 0.0005). Mean anti-MBP IgG and IgM titers were higher in all study groups (p < 0.005) except for LKS compared to both HC and NNI.

CONCLUSION

Children with developmental disorders and epilepsy have higher AAs to several neural antigens compared to controls. The presence of both BDNF AAs and elevated BDNF levels in some children with autism and CDD suggests a previously unrecognized interaction between the immune system and BDNF.

Functional characterisation of autoantibodies from patients with pediatric opsoclonus–myoclonus-syndrome

Paraneoplastic opsoclonus-myoclonus-syndrome (OMS) both in children and adults is suspected to be the result of an autoimmune response directed against cross-reactive proteins of tumor and neuronal cells. We here characterised the binding and functional activities of anti-neuroblastoma antibodies in IgG fractions from 11 OMS children with and without neuroblastoma. IgG fractions from neuroblastoma without OMS (NB) and healthy children served as controls. Indirect immunofluorescence and Western blot revealed IgG binding to intracellular autoantigens in all OMS patients, but in only one of the controls (p<0.001). Using flow cytometry, we could demonstrate surface binding of IgG fractions in all OMS patients, but only in one of control (p<0.001). Moreover OMS IgG exhibited a significant anti-proliferative and a cytotoxic effect on neuroblastoma cells compared to control IgG (p<0.001 and p<0.01). TUNEL assay revealed increased apoptotic cell death of the neuroblastoma cells after exposure to OMS IgG, but not to NB or control IgG (p<0.01). Preabsorption of membrane binding abandoned the anti-proliferative effect of OMS IgG. These findings indicate that surface-binding autoantibodies are present in OMS patients and these autoantibodies cause inhibition of cell proliferation and induce apoptosis.

Opsoclonus myoclonus syndrome in neuroblastoma a report from a workshop on the dancing eyes syndrome at the advances in neuroblastoma meeting in Genoa, Italy, 2004

Opsoclonus-myoclonus syndrome (OMS) is a rare neurologic syndrome that, in children, associates with neuroblastoma in more than half of the cases. The etiology of this condition is thought to be immune mediated, but, though immunosuppressive therapies may ameliorate the acute symptoms, no effective treatment to prevent the common neuropsychologic sequelae has been established. This paper summarizes the results obtained at the 2004 Advances in Neuroblastoma Research meeting, providing status of the art information on immune pathogenesis, clinical features, acute and chronic neurologic manifestations, current and novel therapeutic approaches. It is emphasized that, due to the rarity of OMS in general and neuroblastoma-associated OMS in particular, international collaborations are needed to better define the pathogenesis and therapy of this disease, propose common evaluation criteria and identify new treatment modalities.

Surface-binding autoantibodies to cerebellar neurons in opsoclonus syndrome

Childhood opsoclonus-myoclonus syndrome can occur with or without associated neuroblastoma. An autoimmune pathogenesis has been discussed for both forms. We show here that the majority of children with opsoclonus-myoclonus syndrome (10/14) have autoantibodies binding to the surface of isolated rat cerebellar granular neurons. In some patients, these antibodies are masked by IgG binding to ubiquitous surface antigens, which could be removed by preincubation with the nonneuronal control cell line HEK 293. A newly introduced competitive binding assay showed that the surface binding is directed against the same autoantigen in different patients. Therefore, we hypothesize that opsoclonus-myoclonus syndrome may be the result of an autoimmune process against a neuronal surface protein.

Opsoclonus in three dimensions: oculographic, neuropathologic and modelling correlates

Opsoclonus is a dyskinesia consisting of involuntary, arrhythmic, chaotic, multidirectional saccades, without intersaccadic intervals. We used a magnetic scleral search coil technique to study opsoclonus in two patients with paraneoplastic complications of lung carcinoma. Eye movement recordings provided evidence that opsoclonus is a three-dimensional oscillation, consisting of torsional, horizontal, and vertical components. Torsional nystagmus was also present in one patient. Antineuronal antibody study revealed the presence of anti-Ta (Ma2 onco-neuronal antigen) antibodies in one patient, which had previously been associated only with paraneoplastic limbic encephalitis and brainstem dysfunction, but not opsoclonus, and only in patients with testicular or breast cancer. Neuropathologic examination revealed mild paraneoplastic encephalitis. Normal neurons identified in the nucleus raphe interpositus (rip) do not support postulated dysfunction of omnipause cells in the pathogenesis of opsoclonus. Computer simulation of a model of the saccadic system indicated that disinhibition of the oculomotor region of the fastigial nucleus (FOR) in the cerebellum can generate opsoclonus. Histopathological examination revealed inflammation and gliosis in the fastigial nucleus. This morphological finding is consistent with, but not necessary to confirm, damage to afferent projections to the FOR, as determined by the model. Malfunction of Purkinje cells in the dorsal vermis, which inhibit the FOR, may cause opsoclonus by disinhibiting it.

Opsoclonus-myoclonus-ataxia syndrome in neuroblastoma: clinical outcome and antineuronal antibodies-a report from the Children's Cancer Group Study

BACKGROUND

Opsoclonus-myoclonus-ataxia (OMA) is a paraneoplastic neurologic syndrome affecting 2-3% of children with neuroblastoma. Although children with OMA and neuroblastoma may have higher survival, many experience a significant amount of late neurologic impairment, which may be immunologically mediated. The aim of this study was to compare the outcome of neuroblastoma patients with and without OMA, relating to prognostic factors, treatment, and the presence or absence of anti-neuronal antibodies.

PROCEDURE

Questionnaires were mailed out requesting information on the current neurologic status of patients who submitted sera at diagnosis to the Children's Cancer Group serum bank from 1980 to 1994. Information was requested on clinical and biological patient characteristics as well as clinical aspects of the patients identified as having OMA syndrome, including presentation and treatment for OMA, late sequelae of OMA, the presence or absence of antineuronal antibodies, and survival. Sera from 16 of the OMA patients and 48 case-controls with neuroblastoma were assayed for anti-neuronal antibodies.

RESULTS

Of the 675 responses received, 21 patients had OMA. Ninety percent of OMA patients presented with non-metastatic disease, vs. 35% of non-OMA patients. Estimated 3-year survival for the OMA patients with nonmetastatic disease (stage I, II, III) greater than 1 year of age was 100% vs. 77% for similar non-OMA patients (P = 0.0222). At follow-up, 14/19 evaluable OMA patients displayed some form of developmental or neurologic abnormality. There was no significant correlation of late sequelae with antineuronal antibodies, age, time between OMA symptoms and diagnosis, or treatment given for tumor or OMA. There was a significant correlation of late sequelae with lower stage disease (I and II) compared to more advanced disease (III and IV).

CONCLUSIONS

Patients with OMA and neuroblastoma have excellent survival but a high risk of neurologic sequelae. Favorable disease stage correlates with a higher risk for development of neurologic sequelae. The role of anti-neuronal antibodies in late sequelae of OMA needs further clarification.

Post-vaccinic opsoclonus-myoclonus syndrome: a case report

The opsoclonus-myoclonus syndrome is a pathological condition characterized mainly by involuntary myoclonic movements involving ocular, trunk and limb muscles associated with ataxia and other neurological signs.We describe the case of a 30-year-old woman who developed this syndrome 15days after anti-Rubella vaccination. This case suggests a possible autoimmune post-vaccinic etiopathogenesis of opsoclonus-myoclonus syndrome, rarely described in the literature.

Antineuronal antibodies in patients with neuroblastoma and paraneoplastic opsoclonus-myoclonus

PURPOSE

To identify serologic markers in children with paraneoplastic opsoclonus-myoclonus (POM).

MATERIALS AND METHODS

We examined the sera of 64 children with neuroblastoma (16 with POM and 48 age-matched and stage-matched controls) by immunohistochemistry of rat brain and human cerebellum, and by Western blot analysis of protein extracts from human Purkinje cells, cortical neurons, neuroblastoma cell lines, and HuD.

RESULTS

Using immunohistochemistry, IgG reactivity against neurons was identified in 13 of 16 POM sera (81%), and 12 of 48 non-POM sera (25%; P<0.001). IgM antineural antibodies were present in 3 of 16 POM sera (19%) and 11 of 48 (23%) non-POM sera. Except for anti-Hu antibodies detected in 10 sera (4 with POM), no other specific reactivities were identified by Western blot analysis of neuronal or of neuroblastoma protein extracts.

CONCLUSIONS

We conclude that: 1) patients with neuroblastoma and POM are more likely to harbor antineuronal antibodies than patients without POM; 2) no specific serologic marker of POM was identified, but the frequent presence of antineuronal antibodies suggests that POM is immune-mediated; and 3) anti-Hu antibodies are present in some sera from patients with neuroblastoma, irrespective of the presence of POM.

Paraneoplastic syndromes: an unsolved murder

With neuroimmunology playing an ever greater role in child neurology, paraneoplastic syndromes--uncommon but often devastating complications of cancer--are in the forefront. Abnormalities of both humoral and cellular immunity support the immunological theory of causation. Through co-complicity of host and tumor factors, targets of immunologically mediated injury remote from the tumor may be damaged or destroyed, giving rise to discrete neurological deficits. In the nervous system, the main targets are neuronal nuclei or cell bodies, structural constituents, surface receptors, synapses, and ion channels. The clinical syndromes and response to treatment differ substantially between children and adults. Current pharmacological and biological therapies, which are nonselective, include noncytotoxic and cytotoxic drugs, intravenous immunoglobulins, plasma exchange, and immunoadsorption, some chosen for induction and others for maintenance. Tumor resection and thymectomy are surgical treatments. Combination immunotherapies allow steroid sparing, targeting of more than one immunologic effector pathway, and deploy an advantageous mixture of early- and late-acting drugs. More selective and efficacious immunotherapies are needed.

Abnormal supranuclear eye movements in the child: a practical guide to examination and interpretation

Abnormal eye movements in the infant or voting child can be congenital or acquired. They may be a result of abnormal early visual development or a sign of underlying neurologic or neuromuscular disease. It is important to be able to detect these abnormalities and to distinguish them from normal but immature eye movements. The spectrum of disease in children differs from that in adults. Serious, potentially fatal but treatable disorders can be acquired in infancy, and abnormal eye movements in a sometimes apparently well child should never be labeled as congenital or benign without careful investigation. Eye movement analysis can indicate the presence of an underlying condition and help the clinician to classify different neurologic diseases. It is important to carefully examine the ocular motor system in any children at risk of neurologic disease. This review provides a practical guide to the examination and interpretation of eye movements in the child and includes recent literature on eye movement disorders of childhood. We describe supranuclear abnormalities of the ocular motor system in the order in which we would normally examine it: saccades, pursuit, convergence, vestibulo-ocular reflex, and optokinetic nystagmus. Nystagmus, internuclear ophthalmoplegia, cranial nerve abnormalities, and "miswiring" phenomena (such as Duane's syndrome and synergistic divergence) are not discussed.

Neuroblastoma as a neurobiological disease

While neuroscientists are often involved in the assessment and care of patients with central nervous system tumors, they are only rarely involved in the case of peripheral nervous system neoplasia. Neuroblastoma is a childhood tumor of the primitive sympathetic nervous system. It is at once one of the most common and one of the most deadly tumors of childhood. The prognosis for children with this tumor has not changed in the past two decades. Clearly, a fresh approach to neuroblastoma is needed. The neuroscientist has much to add to our understanding and treatment of neuroblastoma and its sequelae. Conversely, neuroblastoma has much to teach us regarding the normal development of the neural crest and the aberrant loss of neurons in this lineage. A neuroscientist's approach to neuroblastoma, its biology and clinical features, is presented herein.

Central nervous system disease in Langerhans cell histiocytosis

Central nervous system (CNS) disease in Langerhans cell histiocytosis (LCH) is a poorly understood complication of yet unknown frequency. By far the most common manifestation is in the hypothalamic-pituitary system with diabetes insipidus as the leading sign, followed by other endocrinopathies and hypothalamic dysfunction. However, essentially all other parts of the CNS may be involved. On the one hand, space-occupying histiocytic infiltrates may lead to size- and site-depending symptoms, extending from adjacent bone lesions or arising from the meninges or choroid plexus. On the other hand, a progressive neurological deterioration can occur with mainly cerebellar-pontine symptoms. In this article, these clinical patterns are described in correlation with the morphology on MR imaging and histopathology. Further, the therapeutic strategies are reviewed critically, and guidelines for the management of patients with LCH-related CNS disease are presented.

Serum autoantibodies in childhood opsoclonus-myoclonus syndrome: an analysis of antigenic targets in neural tissues

OBJECTIVE

Opsoclonus-myoclonus (OM) is a rare neurologic syndrome affecting children and adults. In children it occurs as a parainfectious process or a paraneoplastic syndrome in association with neuroblastoma. Evidence for an immune mechanism includes the presence of serum autoantibodies to several neural antigens and improvement of symptoms with immunosuppressive therapy. We studied the neural antigenic targets of serum IgM and IgG autoantibodies from nine children with OM.

DESIGN

We studied sera from nine children with OM, three with associated neuroblastoma and six with a prodromal viral illness. Control subjects (n = 77) included four children with neuroblastoma but not OM, 32 children with other neurologic disorders, and 41 with nonneurologic illnesses. We studied the neural antigenic targets of serum IgM and IgG autoantibodies by the following methods: (1) immunostaining of human cerebellar sections and peripheral nerve, and (2) Western blot analysis with human brain fractions including white matter, gray matter, and cerebellar Purkinje cells and nuclei.

RESULTS

Sera from all nine children with OM had IgM and IgG binding to the cytoplasm of cerebellar Purkinje cells and to some axons in white matter. In peripheral nerve, IgM and IgG from all nine OM sera bound to large and small axons. Western blot analysis showed a distinctive pattern of binding to several neural proteins, including a 210 kd antigen identified as the high molecular weight subunit of neurofilament. No control serum showed a similar pattern of reactivity.

CONCLUSION

Opsoclonus-myoclonus syndrome in childhood is associated with a distinctive pattern of serum IgM and IgG binding to neural tissues and antigens.

Antidyskinetic drug therapy for pediatric movement disorders

The pharmacologic armamentarium used to treat dyskinesias in childhood is increasing. Anticonvulsant drugs as a class are still some of the broadest-spectrum antidyskinetic agents, probably because the class includes so many differently acting drugs or because dyskinesias are manifestations of subcortical electrical events. This group is enhanced by recent developments in gamma-aminobutyric acid and glutamate receptor pharmacology, which promise new antidyskinetic drugs. Other drugs acting at receptors for monoamines (dopamine, norepinephrine, and serotonin), acetylcholine, opioids, or histamine may provide symptomatic improvement. Fewer pharmacotherapies address the underlying pathophysiology of movement disorders. Of these, drugs or biologicals for immunomodulation are the most developed, but the group also includes antioxidants, cofactors, metabolic inhibitors, and chelators. There is potential for drugs that block the neurotoxic effects of glutamate to treat movement disorders and reverse or prevent brain injury. Peripheral blockade of focal dyskinesias through botulinum toxin offers a useful alternative to drugs in some patients.

Neuroblastoma-associated opsoclonus-myoclonus treated with intravenously administered immune globulin G

An 18-month-old black girl had progressive truncal ataxia, opsoclonus, and multifocal myoclonus associated with a nonresectable abdominal ganglioneuroblastoma. Before chemotherapy, she received intravenously administered IgG, 1 gm/kg, for 2 days; within 48 hours of the first dose, there was significant improvement of the opsoclonus-myoclonus and ataxia. She required a 1 gm/kg maintenance dose every 4 to 6 weeks for a total of 12 doses, but is now free of symptomatic after 2 years with no therapy.

Intrathecal immune response in patients with neuroborreliosis: specificity of antibodies for neuronal proteins

Cerebrospinal fluid (CSF) and serum samples of 47 patients with serologically proven neuroborreliosis were examined by Western blotting for antibodies to a crude extract of human cortex (CNS) comprising a multitude (> 40) of protein bands. Intrathecal synthesis of total immunoglobulins was determined by the Reiber formula and of autoantibodies to CNS proteins by enzyme-linked immunoassay (ELISA) and by Western blotting. Employing ELISA, intrathecal synthesis of autoantibodies (IgG, IgM and/or IgA) was demonstrated in 40 of 47 patients with neuroborreliosis (85%), in 5 of 40 with multiple sclerosis (12%), and in 22 of 40 with viral meningoencephalitis (55%). Of 40, 35 and 15 patients with neuroborreliosis and an intrathecal synthesis of total IgG, IgM or IgA, 20 revealed an intrathecal production of IgG antibodies (50%), 24 of IgM antibodies (68%) and 6 of IgA autoantiodies (40%) in the CSF. The specificity of autoantibodies differed greatly between most patients. Of 24 different CNS proteins which elicited an immune response in various patients, identities could be determined only for the myelin basic protein (5 of 40) and for the three neurofilament proteins (NF-68, NF-150, NF-200) (13 of 40 patients). In this limited number of patients no significant correlation between individual clinical symptoms and certain autoantiodies could be detected. The higher frequency of intrathecally produced autoantibodies in patients with neuroborreliosis is assumed to result from mitogenic rather than specific activation of autoreactive B-cell clones by Borrelia burgdorferi. The pathogenic relevance of these autoantibodies remains to be determined.

Immune diagnosis of paraneoplastic neurological disease

A continuous stream of new information on clinical, pathological and immunological aspects of paraneoplastic neurological syndromes has been published in recent years. In this survey, we will discuss current opinions on the value of anti-neuronal antibody detection for establishing a diagnosis of one of the paraneoplastic syndromes of the central nervous system.

Immunological and pathological study of anti-Ri-associated encephalopathy

A patient with high titers of the anti-Ri antibody died 3 years after a progressive course with ataxia, opsoclonus, dementia, and peripheral neuropathy. At autopsy, no tumor was found. The nervous system exhibited severe Purkinje cell loss and contained perivascular and interstitial inflammatory infiltrates, particularly involving the brainstem. B and CD4 cells predominated in the perivascular spaces and CD8 cells in the interstitial infiltrates. Complement reactivity and natural killer cells were present and predominated in areas with more intense inflammatory infiltrates. Deposits of IgG were detected in the cytoplasm and nuclei of some neurons, particularly those in the brainstem tegmentum. The proportion of anti-Ri IgG in the total IgG extracted from various areas of the brain, serum, and cerebrospinal fluid was determined by quantitative western blot analysis. Anti-Ri reactivity was identified in immunoblots of all regions of the brain, but it predominated in basis pontis and dorsal mesencephalon. Our findings support the hypothesis of an autoimmune basis for the disorder and suggest that an antibody-mediated mechanism may play a role in its pathogenesis.

Nervous system dysfunction in children with paraneoplastic syndromes

Paraneoplastic syndromes are complexes of symptoms and signs that occur in association with cancer and that are unexplained by the known anatomic and physiologic characteristics of the tumor. Many of these syndromes are neurologic in nature or have consequences for the central or peripheral nervous system. These syndromes have been well characterized in adults. With the exception of opsoclonus-myoclonus, little has been written about the occurrence of such syndromes in children. This review looks at published reports of paraneoplastic syndromes in children and concludes that paraneoplastic syndromes in childhood differ from those seen in adulthood because of differences in both the host and the kinds of neoplasms most prevalent in each age group. Paraneoplastic syndromes may be underreported in childhood because of the difficulty in eliciting specific neurologic complaints from children and because a thorough neurologic examination is often not undertaken as a matter of routine.

An antineuronal autoantibody in paraneoplastic opsoclonus

Sera from 7 patients with paraneoplastic opsoclonus were examined for antineuronal autoantibodies. An antibody against neuronal nuclei was found in serum from a patient with breast cancer, opsoclonus, and ataxia. This antibody recognized 53- to 61-kDa and 79- to 84-kDa antigens in immunoblots of neurons. Antineuronal antibodies were not found in other patients with paraneoplastic opsoclonus.