B- and T-cell markers in opsoclonus-myoclonus syndrome: immunophenotyping of CSF lymphocytes

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.

B cells in the pathophysiology of autoimmune neurological disorders: A credible therapeutic target

There is evidence that B cells are involved in the pathophysiology of many neurological diseases, either in a causative or contributory role, via production of autoantibodies, cytokine secretion, or by acting as antigen-presenting cells leading to T cell activation. Clonal expansion of B cells either in situ or intrathecally and circulating autoantibodies are critical elements in multiple sclerosis (MS), Devic's disease, paraneoplastic central nervous system disorders, stiff-person syndrome, myasthenia gravis, autoimmune demyelinating neuropathies and dermatomyositis. The pathogenic role of B cells and autoantibodies in central and peripheral nervous system disorders, as reviewed here, provides a rationale for investigating whether depletion of B cells with new agents can improve clinical symptomatology and, potentially, restore immune function. Preliminary results from several clinical studies and case reports suggest that B cell depletion may become a viable alternative approach to the treatment of autoimmune neurological disorders.

Rituximab (anti-CD20) adjunctive therapy for opsoclonus-myoclonus syndrome

PURPOSE

To determine if rituximab, an anti-CD20 monoclonal antibody, reduces cerebrospinal fluid (CSF) B-cell expansion in opsoclonus-myoclonus syndrome (OMS) and results in clinical improvement.

METHODS

Sixteen children with OMS and increased % CD20 B-cells in CSF received 4 rituximab infusions (375 mg/m IV) as add-on therapy to corticotropin (ACTH), intravenous immunoglobulins, or both, and were reevaluated 6 months later. Outcome measures were clinical (motor function, behavior, sleep) and immunologic (CSF and blood immunophenotype and Ig levels). Controls were 16 age-matched and sex-matched children, who did not have OMS.

RESULTS

After rituximab, 81% of OMS had a lower motor severity score, and 44% improved one severity category. Mean total score decreased by 44% (P = 0.0005). Rituximab reduced rage score, nighttime awakenings, and the number of children with opsoclonus, action myoclonus, drooling, gait ataxia, and rage. Despite a 51% reduction in ACTH dose, 9 of 11 children on ACTH did not relapse. The percentage of CSF CD19 (and CD20) B-cells was lowered in all children (undetectable in 6), with a 90% reduction in the group mean (P = 0.00003). CSF B-cells were no longer expanded compared with controls. In blood, CD19 B-cells decreased (-90%, P = 0.0003), as did the CSF:blood CD19 B-cell ratio (P = 0.00003). Serum IgM fell by 69% (below reference range), with no statistically significant change in IgG or IgA.

CONCLUSIONS

Rituximab seems efficacious and safe as adjunctive therapy for OMS. Selective targeting of CSF B lymphocytes represents a novel and valuable paradigm shift in the therapy for centrally mediated paraneoplastic disorders.

B cells in health and disease

B cells play a key role in regulating the immune system by producing antibodies, acting as antigen-presenting cells, providing support to other mononuclear cells, and contributing directly to Inflammatory pathways. Accumulating evidence points to disruption of these tightly regulated processes in the pathogenesis of autoimmune disorders. Although the exact mechanisms involved remain to be elucidated, a fundamental feature of many autoimmune disorders is a loss of B-cell tolerance and the inappropriate production of autoantibodies. Dysfunctional immune responses resulting from genetic mutations that cause intrinsic B-cell abnormalities and induction of autoimmunity in the T-cell compartment by B cells that have broken tolerance may also contribute to these disorders. These findings provide the rationale for B-cell depletion as a potential therapeutic strategy in autoimmune disorders and other disease states characterized by inappropriate immune responses. Preliminary results with the CD20-targeted monoclonal antibody rituximab indicate that rituximab can improve symptoms in a number of autoimmune and neurologic disorders (including rheumatoid arthritis, systemic lupus erythematosus, and paraneoplastic neurologic syndromes). Additional studies are warranted to further characterize the role of B cells in autoimmune diseases and the therapeutic utility of B-cell depletion.

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.

Longitudinal neurodevelopmental evaluation of children with opsoclonus-ataxia

OBJECTIVE

We previously reported on children with opsoclonus-ataxia and found pervasive neurodevelopmental deficits, years after onset, without a clear relationship to treatment modality or timing of treatment. A significant negative correlation of functional status with age at testing raised a question of whether opsoclonus-ataxia is a progressive encephalopathy. We attempted to answer this question with serial testing. In addition, we examined the relationship between clinical course and developmental outcome.

METHODS

Thirteen of 17 children with opsoclonus-ataxia, all with neuroblastoma, who were previously reported were reevaluated a second time 2 to 4 years after the initial assessment. One subject who lived out of state was partially reevaluated and is included. Five new subjects (2 with neuroblastoma and 3 without) were also enrolled. Each was evaluated twice at a minimum interval of 1 year between sessions. Intercurrent medical course was recorded, emphasizing medication and relapse history. Cognitive, adaptive behavior, academic, speech and language, and motor abilities were assessed.

RESULTS

For the group as a whole, overall standardized, age-adjusted cognitive scores improved. Generally, younger subjects' cognitive and adaptive behavior scores improved more than older subjects. Although all subjects had gains in speech, language, and motor function, some progressed at a slow pace, and in some instances, standard scores dropped. There was a striking influence of clinical course. Although initial presentation was severe and all subjects required high doses of corticosteroids or corticotropin, 5 had a monophasic course and were able to be weaned from treatment without relapses. Fourteen had multiple relapses over the years, generally with reduction of medication or intercurrent illnesses. Of the 5 children with monophasic course, 4 are currently functioning in the average range with a full-scale IQ of > or =90 and age-appropriate academic and adaptive skills.

CONCLUSIONS

The results continue to raise concern that opsoclonus-ataxia is sometimes a progressive encephalopathy. A minority of children with opsoclonus-ataxia have a monophasic course. Despite initial severity of symptoms, these children may have a more benign prognosis. For the majority of children with opsoclonus-ataxia, the course includes multiple relapses and requires prolonged treatment. Developmental sequelae are significant in these children with chronic course.

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.

Sleep disturbance and rage attacks in opsoclonus-myoclonus syndrome: response to trazodone

OBJECTIVES

Parents of children with opsoclonus-myoclonus syndrome (OMS) frequently describe poor sleep and rage attacks. We hypothesized that these manifestations are related and could result from underlying monoaminergic dysfunction.

STUDY DESIGN

We clinically characterized the sleep and behavioral characteristics of 51 young children with OMS; 19 of those with the most disruptive sleep patterns were treated with trazodone, a soporific serotonergic agent.

RESULTS

Sleep disturbances, including prolonged sleep latency, fragmented sleep, reduced quantity of sleep, snoring, and non-restorative sleep, were reported in 32 children, and frequent rage attacks were reported in 25. In 59% of the poor sleepers, parents felt that the problem was severe enough to warrant treatment. Children sleeping <10 hours/night had a higher rage frequency than those who slept more. Of the children who required trazodone, 84% were receiving corticosteroids or adrenocorticotropic hormone (corticotrophin), compared with 37% in the subgroup with normal sleep. Trazodone (3.0 +/- 0.4 mg/kg/day) improved sleep and behavior in 95% of the children, significantly increasing total sleep time by 72%, decreasing the number of awakenings by 76%, and reducing rage attacks by 33%.

CONCLUSIONS

Children with OMS exhibited multiple types of sleep disturbances, which contributed to rage attacks. Trazodone was effective in improving sleep and decreasing rage attacks and was well tolerated, even in toddlers.

Cerebrospinal fluid ACTH and cortisol in opsoclonus-myoclonus: effect of therapy

Opsoclonus-myoclonus syndrome is one of a few corticotropin (ACTH)-responsive central nervous system disorders of childhood. We measured cerebrospinal fluid ACTH and cortisol in 69 children with opsoclonus-myoclonus and 25 age- and sex-matched control subjects to determine endogenous levels and look for hypothesized differential hormonal effects of ACTH and corticosteroid treatment. Cerebrospinal fluid cortisol was 10-fold higher with ACTH treatment (n = 26), but was unchanged with oral steroid treatment (n = 18) or no treatment (n = 25). It was significantly higher in children receiving daily high-dose ACTH than alternate day ACTH. In ACTH-treated children, cerebrospinal fluid and serum cortisol were highly correlated (r = 0.96, P = 0.0001), with a mean ratio of cerebrospinal fluid to serum cortisol of approximately 1:10. Cerebrospinal fluid ACTH concentration did not differ significantly between untreated opsoclonus-myoclonus and control subjects but was lower with ACTH (-29%) or steroid treatment (-36%), suggesting feedback inhibition of ACTH release. These data delineate differences in the central effects of ACTH and corticosteroid therapy, as well as between high and low ACTH doses, and support the integrity of the brain-adrenal axis in pediatric opsoclonus-myoclonus.

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.

Late presentation of opsoclonus-myoclonus-ataxia syndrome in a child with stage 4S neuroblastoma

Opsoclonus-myoclonus-ataxia syndrome (OMA) in children is most commonly associated with occult neuroblastoma (NB). Although children with OMA and NB have decreased mortality, they suffer from increased neurologic morbidity. The pathogenesis of OMA in NB is not well understood, but current research and treatments support an immune-mediated process. The authors describe an unusual presentation of OMA occurring following 6 months of chemotherapy in a child with stage 4S NB who presented with partial Horner syndrome. Histopathologic examination of his primary cervical tumor showed NB maturation, which may have played a role in precipitating OMA syndrome. Further study of unusual cases of OMA in NB may provide better understanding of the syndrome and additional treatment options for these children.

Secondary tics and tourettism

Motor and phonic tics are most frequently due to Tourette syndrome, but there are many other causes of tics. We analyzed data on 155 patients with tics and co-existent disorders (101M/54F; mean age 40.5 +/- 20.2 years). Fourteen (9.0%) patients had tics associated with an insult to the basal ganglia, such as head trauma (N = 4, 2.5%), stroke (N = 2, 1.2%), encephalitis (N = 3, 1.9%) and other causes. In addition, certain drugs, toxins, and post-infectious causes were associated with tics. Rarely, peripheral injury can cause movement disorders, including tics (N = 1, 0.6%). Pervasive developmental disorders, including Asperger's syndrome (N = 13, 8.3%), mental retardation (N = 4, 2.5%), autism (N = 3, 1.9%), and Savant's syndrome (N = 1, 0.6%), also may be associated with tics, as noted in 21 of the 155 patients (13.5%). Genetic and chromosomal disorders, such as Down's syndrome 5 (3.2%), neuroacanthocytosis (N = 2, 1.2%), and Huntington's disease (N = 1, 0.6%), were associated with tics in 16 patients (10.3%). We have also examined the co-existence of tics and other movement disorders such as dystonia (N = 31, 20.0%) and essential tremor (N = 17, 10.9%). Sixteen (10.3%) patients presented psychogenic tics, and one (0.6%) psychogenic tics and dystonia; conversely, Tourette syndrome preceded the onset of psychogenic dystonia (N = 1, 0.6%), and psychogenic tremor (N = 1, 0.6%) in two patients. Finally, 12 (7.7%) patients had tics in association with non-movement related neurological disorders, such as static encephalopathy (N = 2, 1.2%) and seizures (N = 3, 1.9%). To understand the physiopathology of tics and Tourette syndrome, it is important to recognize that these may be caused or associated with other disorders.

Opsoclonus-myoclonus in an HIV-infected child on antiretroviral therapy--possible immune reconstitution inflammatory syndrome

The exact immunopathogenesis and neuroanatomical localization of opsoclonus-myoclonus ataxia syndrome remains unclear. We describe a 1 year 9 month old girl who, shortly after commencement of highly active antiretroviral therapy developed opsoclonus-myoclonus syndrome and subsequently died of disseminated cytomegalovirus infection. We postulate on the etiological factors that may have played a role in the disease pathogenesis of the patient's opsoclonus-myoclonus ataxia. Immune reconstitution inflammatory syndrome was considered the most likely because of the initial CD4 depletion and the onset of symptoms shortly after initiation of antiretroviral therapy. Single photon emission computed tomography (SPECT) proved helpful by localizing the area of dysfunction to the cerebellar vermis.

Immunologic and clinical responses to rituximab in a child with opsoclonus-myoclonus syndrome

Opsoclonus-myoclonus syndrome (OMS) is an autoimmune disorder with serious neurodevelopmental morbidity and limited treatment options. We treated a toddler with moderately severe OMS with rituximab, a monoclonal anti-B cell antibody. The patient's clinical response was documented on videotape and scored with the OMS Evaluation Scale. Cerebrospinal fluid lymphocyte subsets were evaluated by flow-cytometric immunophenotyping, with a comprehensive panel of monoclonal antibodies. Eradication of cerebrospinal fluid B cells, which previously were expanded, was associated with dramatic clinical improvement. There also were secondary changes in other lymphocyte subsets that might be relevant to the clinical response and lack of serious infections. In addition to clarifying the immune response to B-cell depletion, these data reveal a promising new therapy for OMS that warrants a phase I clinical trial.

Immunophenotype of blood lymphocytes in neuroblastoma-associated opsoclonus-myoclonus

OBJECTIVE

To determine whether the distribution of peripheral blood mononuclear cells (PBMCs) is altered in paraneoplastic opsoclonus-myoclonus (POM).

METHODS

PBMCs from 17 children with POM, 17 children with OM but no tumor, and 17 controls were immunophenotyped using a comprehensive panel of surface markers by dual-laser flow cytometry. All groups were matched for age and gender; POM and OM patients were matched for treatment.

RESULTS

In the POM patients, the CD4+ T-cell subset was smaller in both relative size (-18%, P = 0.02) and absolute size (-41%, P = 0.03) compared with controls. The CD4/CD8 ratio also was less (-29% to -44%) and was related to POM duration (P = 0.03). The absolute but not relative size of the gammadelta T-cell subset was reduced (-44%, P = 0.02). There were no significant abnormalities of CD19+ B-cells, CD3- or CD3+ NK cells, HLA-DR+ or CD25+ T-cells, or CD45RA+ or CD45RO+ T-cells. Prior tumor chemotherapy, which was associated with a higher percentage but not number of CD8+ T-cells, did not restore the CD4+ T-cell subset. When the POM and OM groups, which were not significantly different, were combined, chemotherapy decreased both the relative and absolute size of the CD19+ B-cell pool and had small effects on other lymphocyte subsets.

CONCLUSIONS

POM is characterized by T-cell abnormalities of PBMCs, the most robust of which is reduction of the CD4+ T-cell subset and the CD4/CD8 ratio. Although this reduction was found previously in cerebrospinal fluid in POM patients, PBMC subsets did not otherwise reflect cerebrospinal fluid abnormalities. Longitudinal studies will be necessary to determine whether PBMC abnormalities could serve as treatment markers.