Extended interval dosing of natalizumab in multiple sclerosis.

BACKGROUND: Natalizumab (NTZ), a monoclonal antibody to human α4ß1/ß7 integrin, is an effective therapy for multiple sclerosis (MS), albeit associated with progressive multifocal leukoencephalopathy (PML). Clinicians have been extending the dose of infusions with a hypothesis of reducing PML risk. The aim of the study is to evaluate the clinical consequences of reducing NTZ frequency of infusion up to 8 weeks 5 days. METHODS: A retrospective chart review in 9 MS centres was performed in order to identify patients treated with extended interval dosing (EID) regimens of NTZ. Patients were stratified into 3 groups based on EID NTZ treatment schedule in individual centres: early extended dosing (EED; n=249) every 4 weeks 3 days to 6 weeks 6 days; late extended dosing (LED; n=274) every 7 weeks to 8 weeks 5 days; variable extended dosing (n=382) alternating between EED and LED. These groups were compared with patients on standard interval dosing (SID; n=1093) every 4 weeks. RESULTS: 17% of patients on SID had new T2 lesions compared with 14% in EID (p=0.02); 7% of patients had enhancing T1 lesions in SID compared with 9% in EID (p=0.08); annualised relapse rate was 0.14 in the SID group, and 0.09 in the EID group. No evidence of clinical or radiographic disease activity was observed in 62% of SID and 61% of EID patients (p=0.83). No cases of PML were observed in EID group compared with 4 cases in SID cohort. CONCLUSIONS: Dosing intervals up to 8 weeks 5 days did not diminish effectiveness of NTZ therapy. Further monitoring is ongoing to evaluate if the risk of PML is reduced in patients on EID.

Expansion of CD27high plasmablasts in transverse myelitis patients that utilize VH4 and JH6 genes and undergo extensive somatic hypermutation.

Patients with the autoimmune disease multiple sclerosis (MS) typically present with the clinically isolated syndromes (CIS) transverse myelitis (TM) or optic neuritis (ON). B-cell disturbances have been well documented in patients with MS and CIS patients with ON, but not in CIS patients with TM, despite the fact that these patients have the worst clinical outcome of all CIS types. The goal of this study was to characterize the B-cell populations and immunoglobulin genetics in TM patients. We found a unique expansion of CD27(high) plasmablasts in both the cerebrospinal fluid and periphery of TM patients that is not present in ON patients. Additionally, plasmablasts from TM patients show evidence for positive selection with increased somatic hypermutation accumulation in VH4(+) B cells and receptor editing that is not observed in ON patients. These characteristics unique to TM patients may impact disease severity and progression.

A unique antibody gene signature is prevalent in the central nervous system of patients with multiple sclerosis.

B cells isolated from the CSF of patients with multiple sclerosis (MS) have a unique accumulation of somatic hypermutation within the B cell receptor, termed the antibody gene signature (AGS). The focus of this study was to investigate whether the AGS could also be detected in MS brain tissue. Genetic analysis of B cells isolated from post-mortem CNS tissue samples from four MS brains demonstrated that signature enriched B cells are present at the site of tissue injury as well as in the circulating CSF.

Immunologic, clinical, and radiologic status 14 months after cessation of natalizumab therapy.

OBJECTIVE: Natalizumab is a humanized recombinant monoclonal antibody against very late activation antigen-4 approved for the treatment of patients with multiple sclerosis (MS). A phase II study failed to demonstrate a difference between natalizumab treatment groups and the placebo group with regard to gadolinium enhancing lesions on MRI 3 months after discontinuation of therapy. The objective of this study was to assess clinical MS disease activity, surrogate disease markers on MRI, immunologic parameters in peripheral blood and CSF, as well as safety in patients with MS after discontinuation of natalizumab therapy. METHODS: This study is a longitudinal and serial cross-sectional assessment, in which 23 patients who were treated with natalizumab in the context of two phase III clinical trials were originally enrolled. A subgroup of patients was followed over 14 months. The annual relapse rate, neurologic disease progression assessed by the Expanded Disability Status Scale, disease surrogate markers on MRI, cellular and humoral immune markers in peripheral blood and CSF, and adverse events of the drug were monitored. RESULTS: With regard to clinical disease activity, neuroimaging, and immune responses, the majority of patients in our cohort were stable. Decreased lymphocyte cell numbers and altered cell ratios returned to normal 14 months after cessation of natalizumab. No infectious complications were observed. CONCLUSION: This is the first long-term follow-up of patients who discontinued natalizumab. We did not observe a clinical, radiographic, or immunologic rebound phenomenon after discontinuation of natalizumab therapy.

Characterizing the mechanisms of progression in multiple sclerosis: evidence and new hypotheses for future directions.

Major advancements have been achieved in our ability to diagnose multiple sclerosis (MS) and to commence treatment intervention with agents that can favorably affect the disease course. Although MS exacerbations and the emergence of disability constitute the more conspicuous aspects of the disease process, evidence has confirmed that most of the disease occurs on a constitutive and occult basis. Disease-modifying therapies appear to be modest in the magnitude of their treatment effects, particularly in the progressive stage of the disease. Therapeutic strategies currently used for MS primarily target the inflammatory cascade. Several potential mechanisms appear to be involved in the progression of MS. Characterizing these mechanisms will result in a better understanding of the various forms of the disorder and how to effectively treat its clinical manifestations. It is our objective within this 2-part series on progression in MS to offer both evidence-based observations and hypothesis-driven expert perspectives on what constitutes the cause of progression in MS. We have chosen areas of inquiry that appear to have been most productive in helping us to better conceptualize the landscape of what MS looks like pathologically, immunologically, neuroscientifically, radiographically, and genetically. We have attempted to advance hypotheses focused on a deeper understanding of what contributes to the progression of this illness and to illustrate new technical capabilities that are catalyzing novel research initiatives targeted at achieving a more complete understanding of progression in MS.

Immunoglobulin Vlambda light chain gene usage in patients with Sjögren's syndrome.

OBJECTIVE: To determine whether patients with Sjögren's syndrome (SS) have abnormalities in Ig Vlambda and Jlambda gene usage, differences in somatic hypermutation, defects in selection, or indications for perturbations of B cell maturation. METHODS: Individual peripheral B cells from SS patients were analyzed for their Vlambda gene usage by single-cell polymerase chain reaction amplification of genomic DNA and compared with those from normal controls. RESULTS: Molecular differences from controls in Vlambda-Jlambda recombination were identified that were reflected by findings in the nonproductive Vlambda repertoire of the patients, including enhanced rearrangement of Vlambda10A and Jlambda2/3 gene segments. In addition, a number of abnormalities in the productive repertoire were identified, indicating disordered selection. A greater usage of 4 Vlambda genes (2A2, 2B2, 2C, and 7A), representing 56% of all productive Vlambda rearrangements, was observed, suggesting positive selection of these genes. Overutilization of Jlambda2/3 and underutilization of Jlambda7 in both nonproductive and productive Vlambda rearrangements of SS patients compared with controls suggested decreased receptor editing in SS. The mutational frequency did not differ from that in controls, and positive selection of mutations into the productive V gene repertoire was found, similar to that in controls, although mutational targeting toward RGYW/WRCY motifs, typically found in controls, was not found in SS patients. CONCLUSION: Disturbed regulation of B cell maturation with abnormal selection, defects in editing Ig receptors, and abnormal mutational targeting may contribute to the emergence of autoimmunity in SS.

The role of CD40-CD40 ligand (CD154) interactions in immunoglobulin light chain repertoire generation and somatic mutation.

To determine whether CD40 ligation influences the molecular and selective mechanisms that govern the development of the human Ig light chain repertoire, analysis of the Vkappa and Vlambda repertoires of CD19+ B cells obtained from a patient with X-linked hyper IgM syndrome (XHIM) and a nonfunctional CD154 was carried out. The nonproductive Vkappa and Vlambda repertoires were largely comparable to that of the normals with respect to V gene and J segment distribution as well as CDR3 length and VLJL joint complexity. Comparison of the nonproductive and productive repertoires indicated that a limited number of VL genes were positively and negatively selected in the XHIM patient. Although mutations were observed in the XHIM VL repertoires, the frequency of mutations was significantly lower than in normals. Typical targeting of these mutations into RGYW/WRCY motifs was significantly reduced and subsequent selection of RGYW/WRCY mutations, which is normally observed, was not found. These results indicate that CD40 ligation is not required for generation of the light chain repertoire, positive selection of some Vk rearrangements, negative selection of specific VL genes, and some degree of somatic mutation. Importantly, however, targeting of mutations to RGYW/WRCY motifs and subsequent selection of these mutated motifs does not occur in the absence of CD40 ligation.

Autonomic regulation of neuroimmunological responses: implications for multiple sclerosis.

The expression of neural regulatory molecules by immune cells that infiltrate the nervous system upon injury may be a mechanism for cross regulation between the nervous system and the immune system. Several lines of evidence implicate nerve growth factor signaling through its receptors as a potential source of communication between the two systems. The expression of beta-adrenergic receptors and sympathetic innervation of lymphoid organs represents another example of communication between the immune and the nervous system. In this review, we discuss mechanisms of how factors in common between the nervous system and the immune system may result in regulatory circuits which are important in both healthy and diseased states. These studies may have relevance for a number of inflammatory conditions in humans, including multiple sclerosis.

A p74 common gamma receptor chain isoform facilitates IL-2 and IL-15 responses by the myelomonocytic cell line Tf-1beta2.

Functional forms of the IL-2, IL-4, IL-7, IL-9, and IL-15 receptors require the gamma c receptor component. We have described previously a myeloid cell line called Tf-1beta, which binds IL-2 with intermediate-affinity and proliferates in response to IL-2. In this study, we characterize gamma c expression on Tf-1beta2 cells, a derivative of Tf-1beta cells stimulated exclusively with IL-2. Although Tf-1beta2 cells bind IL-2 with intermediate-affinity and proliferate in response to IL-2, this cell line does not express the p64 gamma c chain at the protein level. This result was surprising because prior studies suggest these cells should not be expected to proliferate in response to IL-2 or IL-15 in the absence of the p64 gamma c chain. A p74 protein was detected by western blot following immunoprecipitation with an anti-gamma c polyclonal antibody, and a p74 protein was identified consistently in complex with IL-2 and IL-15 on these cells. However, the gamma c gene in these Tf-1beta2 cells shows no evidence of mutation by sequence analysis. Furthermore, inhibition of glycosylation of these Tf-1beta2 cells by tunicamycin treatment yields a standard 39-kDa molecule recognized on western blot with anti-gamma c antibody, as seen for the standard 64-kDa isoform of gamma c. These results demonstrate that a 74-kDa gamma c receptor isoform was involved in the response of the Tf-1beta2 cells to cytokines which normally interact with the 64-kDa gamma c chain.

The V lambda J lambda repertoire in human fetal spleen: evidence for positive selection and extensive receptor editing.

VlambdaJlambda rearrangements obtained from genomic DNA of individual IgM(+) B cells from human fetal spleen were analyzed. A nonrandom pattern of lambda gene rearrangements that differed from the adult Vlambda repertoire was found. The Vlambda distal genes 8A and 4B were absent from the nonproductive fetal repertoire, whereas 2E and 3L were overrepresented and 1B was underrepresented in the productive fetal repertoire. Positive selection of the Vlambda gene, 2E, along with Vlambda rearrangements employing homologous VlambdaJlambda joins were observed in the fetal, but not in the adult Vlambda repertoire. Overrepresentation of Jlambda distal cluster C genes rearranging to the Vlambda distal J segment, Jlambda7, in both productive and nonproductive fetal repertoires suggested that receptor editing/replacement was more active in the fetus than in adults. Numerous identical VlambdaJlambda junctions were observed in both the productive and nonproductive repertoire of the fetus and adult, but were significantly more frequent in the productive repertoire of the fetus, suggesting expansion of B cells expressing particular lambda-light chains in both stages of development, with more profound expansion in the fetal repertoire. Notably, B cells expressing identical lambda-light chains expressed diverse heavy chains. These data demonstrate that three mechanisms strongly influence the shaping of the human fetal lambda-chain repertoire that are less evident in the adult: positive selection, receptor editing, and expansion of B cells expressing specific lambda-light chains. These events imply that the expressed fetal repertoire is shaped by exposure to self Ags.

Targeting and selection of mutations in human Vlambda rearrangements.

The impact of somatic hypermutation on the lambda light chain repertoire of individual IgM+ peripheral B cells in the absence (nonproductive rearrangements) and presence (productive rearrangements) of selective influences was analyzed. In the 27 mutated nonproductive VlambdaJlambda, rearrangements obtained from individual peripheral B cells, a significantly greater mutational frequency was observed in the complementarity-determining region (CDR) in comparison to the framework region (FR), whereas the mutational frequencies in both the CDR and FR of the 100 mutated productive VlambdaJlambda rearrangements were significantly greater. R mutations were introduced comparably in CDR and FR of nonproductive VlambdaJlambda rearrangements, but were significantly decreased in FR of productive VlambdaJlambda rearrangements. The majority of codons defined as hot spots for R mutations were within CDR in both the nonproductive and productive VlambdaJlambda rearrangements. Targeting of mutations to RGYW/WRCY motifs was observed such that 38% of all mutations in the nonproductive VlambdaJlambda rearrangements were within RGYW/WRCY motifs. Mutations in RGYW/WRCY motifs were positively selected and accounted for >50% of all mutations in the mutated productive VlambdaJlambda rearrangements. These data indicate that targeting of the mutational machinery and selection of mutations in these targeted motifs play major roles in influencing nucleotide changes in VlambdaJlambda rearrangements.

The influence of CD40-CD154 interactions on the expressed human V(H) repertoire: analysis of V(H) genes expressed by individual B cells of a patient with X-linked hyper-IgM syndrome.

Analysis of the V(H)DJ(H) repertoire of peripheral blood IgM(+) B cells from a patient with X-linked hyper-IgM syndrome (X-HIgM) was undertaken to determine whether the distribution of V(H) families in the productive repertoire might be regulated by in vivo CD40-CD154 interactions. The distribution of V(H) genes in the non-productive repertoire of IgM(+) B cells was comparable in X-HIgM and normals. Unlike the normal productive V(H) repertoire, however, in the X-HIgM patient the V(H)4 family was found at almost the same frequency as the V(H)3 family. This reflected a diminution in the positive selection of the V(H)3 family observed in normals and the imposition of positive selection of the V(H)4 family in the X-HIgM patient. Unique among the V(H)3 genes, V(H)3-23/DP-47 was positively selected in both normals and the X-HIgM patient. No major differences in the usage of J(H) or D segments or the complementarity-determining region (CDR) 3 were noted, although the foreshortening of the CDR3 noted in the mutated V(H) rearrangements of normals was absent in the X-HIgM patient. Finally, a minor degree of somatic hypermutation was noted in the X-HIgM patient. These results have suggested that specific influences on the composition of the V(H) repertoire in normals require CD40-CD154 interactions.

Eating disorders and psychiatric disorders in the first-degree relatives of obese probands with binge eating disorder and obese non-binge eating disorder controls.

OBJECTIVE: The purposes of the present study were to examine the possibility of a familial tendency for binge eating disorder (BED) among the obese, to clarify the relationship between BED and other eating disorders, and to test the relationship between BED and other psychiatric disorders. METHOD: We studied 32 female BED outpatients and 23 obese females without BED. A possible history of eating disorders was assessed using the Structured Clinical Interview for DSM-III-R-Eating Disorders section administered by telephone interview. Family history information for other psychiatric disorders was collected using the Family History Research Diagnostic Criteria RESULTS: The frequency of all eating disorders and the risk for other psychiatric disorders were not significantly different between the relatives of the two groups. These results were consistent across generation and gender. DISCUSSION: This study failed to show a familial tendency for BED, or any significant familial relationship between BED and other eating disorders, and did not support the hypothesis of coaggregation of other psychiatric disorders with BED.

Two-dimensional cancellation neglect a review and suggested method of analysis.

Directional bias on cancellation has thus far not been standardized. While cancellation tasks are primarily used to assess lateral performance asymmetries, they may also reveal two-dimensional (i.e., combined lateral and radial) neglect patterns. We propose a method to evaluate and report cancellation neglect regardless of whether the neglect pattern is strictly unilateral or two-dimensional. Our method establishes the location of the geographic center of all neglected stimuli relative to the page center by averaging their Cartesian coordinates. This "neglect center" is reported in polar coordinates to indicate its distance and direction from the page center. We apply our method to published examples of two-dimensional neglect. We find that neglect centers from different cancellation performances may not be statistically distinct even though they may occupy different quadrants. In addition, the net direction of neglect found by the coordinate method may differ from that inferred from measuring differences in quadrant omission totals. The suitability of the coordinate vs. the quadrant method will depend on the mechanism hypothesized for visuospatial exploration under particular test conditions. Using both approaches may detect different attentional biases operating during the same task. The coordinate method is appropriate for conventional cancellation testing. By incorporating the precise locations of all neglected stimuli and determining the net neglect direction in two dimensions, the technique may stimulate more comprehensive explanations for directional bias.

Age vs. aging in the pathogenesis of senile dementia of the Alzheimer type: electrophysiological evidence.

Is senile dementia of the Alzheimer type (SDAT) the end result of aging of the brain (serial or aging-related model) or the result of some other mechanism that runs in parallel to normal aging (parallel or age-related model)? This question can be answered by comparing variables that measure biological aging (aging-dependent variables, ADVs) of normal individuals and of SDAT patients. If the serial model applies, the values of the ADVs of SDAT patients should be at the upper end of the normal ADV curves. In control individuals the power of the alpha band in the 2-Hz flash-stimulated EEG at the posterior head regions increased with age, while the power of the delta band in the resting EEG at the anterior head regions decreased. In SDAT patients the ADVs were significantly different from normal and opposite to the trend of normal aging, supporting the parallel model and suggesting that the pathogenesis of SDAT is different from normal aging.

Cognition-related EEG abnormalities in nondemented Down syndrome subjects.

Down syndrome (DS) subjects develop Alzheimer disease (AD) histopathology before they develop dementia. We compared the resting and flash stimulated electroencephalogram (EEG) of nondemented adult DS and age-matched control subjects, in search of EEG abnormalities that might correlate with AD histopathology. DS subjects had increased absolute power in all the EEG bands, independent of cognition functions measured by the Mini Mental State Examination and Picture Absurdities Test scores. In the power spectrum of the resting EEG, we found a cognition-related increase in power at 4.5 and 8.8 Hz, indicative of alpha-slowing, as in AD patients. In the stimulated EEG, we found several cognition-related abnormalities, such as decreased responses to 12-Hz stimulation and decreased integral of beta- and gamma-band responses, indicative of decreased responsiveness to photic stimulation, as in AD patients. Therefore, nondemented DS and AD patients share several cognition related EEG abnormalities which are probably due to AD histopathology.

Problem solving by patients with multiple sclerosis: comparison of performance on the Wisconsin and California Card Sorting Tests.

Problem solving by patients with clinically definite multiple sclerosis (MS) was examined using the Wisconsin and California Card Sorting Tests (WCST and CCST). On the WCST, the MS patients achieved fewer categories and made more perseverative responses and errors than controls, confirming results of several previous studies. On the CCST, the MS patients generated and identified fewer concepts, but they performed normally when sorting was cued by the experimenter and they made no more perseverations than controls. Although findings from the WCST indicate that the problem solving deficits by MS patients closely resemble those exhibited by patients with various conditions that produce frontal lobe dysfunction, results from the CCST indicate that the problem solving difficulties exhibited by patients with MS are distinct and probably represent a primary deficit in concept formation.

Severity of dementia correlates with loss of broad-band visual cortical responses.

We have shown that the response to flash stimulation of the occipital electroencephalogram (EEG) in Alzheimer disease (AD) patients is smaller than in normal subjects. To ascertain whether this is a specific feature of AD or a nonspecific effect of dementia, we investigated in AD and multi-infarct dementia (MID) patients the relationship between cognitive function, measured as Mini-Mental State Examination score, and EEG power response, measured as the difference in spectral power between flash-stimulated EEG and resting EEG. Both variables were positively correlated and the regression equations of AD and MID patients were not significantly different, showing nonspecificity. The coupling between cognitive function and power response is discussed in relation to the dynamic binding hypothesis of cognition.