Elizabeth D. Tate

B- and T-cell markers in opsoclonus–myoclonus syndrome Immunophenotyping of CSF lymphocytes

Background: Although many lines of evidence suggest an autoimmune etiology, the pathophysiology of opsoclonus–myoclonus syndrome (OMS) remains poorly understood and no immunologic abnormalities have correlated with neurologic severity. Conventional immunotherapies often do not prevent relapse or permanent sequelae. Objective: To test the cellular immune hypothesis of OMS in a cross-sectional study and determine if CSF lymphocyte subset analysis provides biomarkers of disease activity. Methods: The expression of lymphocyte surface antigens was investigated in CSF and blood of 36 children with OMS and 18 control subjects, using a comprehensive panel of monoclonal antibodies to adhesion and activation proteins in combination with anti-CD3 and anti-CD45 antibodies in four-color fluorescence-activated cell sorting. Results: Although most children with OMS had normal CSF cell counts, they exhibited expansion of CD19+ B-cell (up to 29%) and γδ T-cell (up to 26%) subsets and a lower percentage of CD4+ T-cells and CD4/CD8 ratio, which persisted even years after disease onset and conventional treatments. The percentage of activated CSF T-cells was also higher. Abnormalities correlated with neurologic severity, as scored blinded from videotapes using a 12-item motor scale, and disease duration. No significant differences were found between tumor and no-tumor groups. In children with neuroblastoma, tumor resection or cancer chemotherapy did not alter immunologic abnormalities. Conclusions: CSF B- and T-cell recruitment is linked to neurologic signs in pediatric OMS, which may relate to relapses and disease progression.

Neuroepidemiologic Trends in 105 US Cases of Pediatric Opsoclonus-Myoclonus Syndrome

Opsoclonus-myoclonus syndrome (OMS) is a rare, autoimmune neurological disorder that is poorly recognized and undertreated. Neuroblastoma is found in one half of the cases. Because of the high incidence of spontaneous regression of neuroblastoma, it is unknown whether not finding a tumor means there was none. To define demographic trends and the standard of care in the first large series of OMS, 105 children were recruited over a 13-year period in a retrospective questionnaire survey. Children with and without a tumor differed little in viral-like prodrome and neurological symptoms. Earliest neurological symptoms were staggering and falling, leading to a misdiagnosis of acute cerebellitis. Later symptoms included body jerks, drooling, refusal to walk or sit, speech problems, decreased muscle tone, opsoclonus, and inability to sleep. Tumor resection alone did not provide adequate therapy for most. Adrenocorticotropic hormone (ACTH), prednisone, and intravenous immunoglobulin were used with equal frequency, but ACTH was associated with the best early response. More than one half of the children had relapses. Residual behavioral, language, and cognitive problems occurred in the majority. The delay in diagnosis (11 weeks) and initiation of treatment (17 weeks) is unacceptably long.

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/m2 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.

CSF B-Cell Expansion in Opsoclonus-Myoclonus Syndrome: A Biomarker of Disease Activity

Lack of a biomarker of disease activity has hindered the therapy of childhood opsoclonus‐myoclonus syndrome (OMS), which is purported to be mediated humorally. To determine if the cerebrospinal fluid (CSF) B lymphocyte, which may traffic into the central nervous system (CNS) to produce antibody locally, is one such biomarker, B lymphocytes were immunophenotyped in the CSF and blood of 56 children with OMS and 26 pediatric controls by dual‐laser flow cytometry. Neurological severity was rated blindly from videotapes using a validated 12‐item motor evaluation scale. Children with OMS manifested a 4‐ to 7‐fold higher percentage of total B‐cells in CSF (P < 0.0001), including CD5+ (P = 0.001) and CD5− (P = 0.0004) B‐cell subsets, compared with controls, in whom the percentages were negligible and unchanging with age. CSF expansion of both B‐cell subsets increased with disease severity and decreased with disease duration (P ≤ 0.0001, ANOVA). Previous treatment with conventional immunotherapies, chemotherapy, or tumor resection had not normalized B‐cell percentages in those with lingering symptoms. These studies reveal that CSF B‐cell expansion in OMS is characteristic and often persistent. Presence of the autoreactive CD5+ B‐cell subset and correlations with neurological severity and disease duration suggest CSF B‐cell expansion is a biomarker of disease activity and possible target for B‐cell–specific therapy. Immunophenotyping of CSF lymphocytes by flow cytometry yields valuable clinical information missed by routine studies and allows crucial treatment decisions to be made rapidly.

Screening for Autoantibodies in Children With Opsoclonus-Myoclonus-Ataxia

Various paraneoplastic autoantibodies have been linked to discrete neurologic syndromes and tumors in adults, but little is known about their incidence in children. We report a cross-sectional study of known paraneoplastic antibodies in 59 children with opsoclonus-myoclonus-ataxia, 86% of whom were moderately or severely symptomatic, and 68% of whom had relapsed at the time of testing. This total number of patients includes 18 children with low-stage neuroblastoma (tested after tumor resection), six of whom had never been treated with immunosuppressants. All were seronegative for anti-Hu, anti-Ri, and anti-Yo, the three paraneoplastic antibodies most associated with opsoclonus-myoclonus or ataxia in adults. These data contrast with reports of anti-Hu-positive sera in children with high-stage tumors and suggest that anti-Hu, anti-Ri, and anti-Yo do not explain relapses in pediatric opsoclonus-myoclonus-ataxia. They underscore the need to search for unique autoantibodies, as well as cellular mechanisms of pediatric paraneoplastic disease.

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 patients 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.

B Cell Depletion Therapy for New-Onset Opsoclonus-Myoclonus

Twelve immunotherapy‐naïve children with opsoclonus‐myoclonus syndrome and CSF B cell expansion received rituximab, adrenocorticotropic hormone (ACTH), and IVIg. Motor severity lessened 73% by 6 mo and 81% at 1 yr (P < 0.0001). Opsoclonus and action myoclonus disappeared rapidly, whereas gait ataxia and some other motor components improved more slowly. ACTH dose was tapered by 87%. Reduction in total CSF B cells was profound at 6 mo (‐93%). By study end, peripheral B cells returned to 53% of baseline and serum IgM levels to 63%. Overall clinical response trailed peripheral B cell and IgM depletion, but improvement continued after their levels recovered. All but one non‐ambulatory subject became ambulatory without additional chemotherapy; two relapsed and remitted; four had rituximab‐related or possibly related adverse events; and two had low‐titer human anti‐chimeric antibody. Combination of rituximab with conventional agents as initial therapy was effective and safe. A controlled trial with long‐term safety monitoring is indicated.

Key role of CXCL13/CXCR5 axis for cerebrospinal fluid B cell recruitment in pediatric OMS

To study aberrant B cell trafficking into the CSF in opsoclonus-myoclonus syndrome (OMS), chemoattractants CXCL13 and CXCL12, and B cell frequency and CXCR5 expression, were evaluated. CSF CXCL13 concentration and the CSF/serum ratio were higher in untreated OMS than controls, related directly to OMS severity and inversely to OMS duration, and correlated with CSF B cell frequency and oligoclonal bands. CXCL12 showed the opposite pattern. Selective accumulation of CXCR5+ memory B cells in CSF was found. In ACTH-treated OMS, CXCL13, but not CXCL12, was lower. These data implicate the chemokine/chemoreceptor pair CXCL13/CXR5 in B cell recruitment to the CNS in OMS. CXCL13 and CXCL12 may serve as reciprocal biomarkers of disease activity, but CXCL13 also had utility as a treatment biomarker.

Active Comparator-Controlled, Rater-Blinded Study of Corticotropin-Based Immunotherapies for Opsoclonus-Myoclonus Syndrome

To test the efficacy and safety of corticotropin-based immunotherapies in pediatric opsoclonus-myoclonus syndrome, 74 children received corticotropin alone or with intravenous immunoglobulin (groups 1 and 2, active controls); or both with rituximab (group 3) or cyclophosphamide (group 4); or with rituximab plus chemotherapy (group 5) or steroid sparers (group 6). There was 65% improvement in motor severity score across groups (P < .0001), but treatment combinations were more effective than corticotropin alone (P = .0009). Groups 3, 4, and 5 responded better than group 1; groups 3 and 5 responded better than group 2. The response frequency to corticotropin was higher than to prior corticosteroids (P < .0001). Fifty-five percent had adverse events (corticosteroid excess), more so with multiagents (P = .03); and 10% had serious adverse events. This study demonstrates greater efficacy of corticotropin-based multimodal therapy compared with conventional therapy, greater response to corticotropin than corticosteroid-based therapy, and overall tolerability.

Therapeutic down-regulation of central and peripheral B-cell-activating factor (BAFF) production in pediatric opsoclonus-myoclonus syndrome

Opsoclonus-myoclonus syndrome (OMS) is an autoimmune, paraneoplastic, central nervous system disorder, characterized by cerebrospinal fluid (CSF) B-cell expansion and various putative autoantibodies. To investigate the role of B-cell activating factor (BAFF) in OMS and the effect of disease-modifying immunotherapies used to treat it, BAFF was measured by enzyme-linked immunoadsorbent assay in the CSF and serum of 161 children with OMS and 116 pediatric controls. The mean concentration of CSF BAFF and the CSF/serum BAFF ratio were significantly higher in untreated OMS compared to neurological controls. CSF and serum BAFF levels were significantly lower in children treated with ACTH or corticosteroids, as was the CSF/serum BAFF ratio. There was a strong, negative correlation between CSF or serum BAFF levels and ACTH dose. Monthly IVIg infusions had no net impact on BAFF levels, and the combination of IVIg with ACTH or steroids did not reduce or enhance their anti-BAFF effects. These data indicate that BAFF production is increased centrally, not peripherally, in OMS, implying astrocytic over production. The novel dose-related central and peripheral anti-BAFF properties of ACTH, especially, have implications for other BAFF-related autoimmune disorders, infectious diseases, and cancers.