The Gut Microbiome in Neuromyelitis Optica

Neuromyelitis optica (NMO) is a rare, disabling, sometimes fatal central nervous system inflammatory demyelinating disease that is associated with antibodies ("NMO IgG") that target the water channel protein aquaporin-4 (AQP4) expressed on astrocytes. There is considerable interest in identifying environmental triggers that may elicit production of NMO IgG by AQP4-reactive B cells. Although NMO is considered principally a humoral autoimmune disease, antibodies of NMO IgG are IgG1, a T-cell-dependent immunoglobulin subclass, indicating that AQP4-reactive T cells have a pivotal role in NMO pathogenesis. When AQP4-specific proliferative T cells were first identified in patients with NMO it was discovered that T cells recognizing the dominant AQP4 T-cell epitope exhibited a T helper 17 (Th17) phenotype and displayed cross-reactivity to a homologous peptide sequence within a protein of Clostridium perfringens, a commensal bacterium found in human gut flora. The initial analysis of gut microbiota in NMO demonstrated that, in comparison to healthy controls (HC) and patients with multiple sclerosis, the microbiome of NMO is distinct. Remarkably, C. perfringens was the second most significantly enriched taxon in NMO, and among bacteria identified at the species level, C. perfringens was the one most highly associated with NMO. Those discoveries, along with evidence that certain Clostridia in the gut can regulate the balance between regulatory T cells and Th17 cells, indicate that gut microbiota, and possibly C. perfringens itself, could participate in NMO pathogenesis. Collectively, the evidence linking microbiota to humoral and cellular immunity in NMO underscores the importance for further investigating this relationship.

Induction of Paralysis and Visual System Injury in Mice by T Cells Specific for Neuromyelitis Optica Autoantigen Aquaporin-4

While it is recognized that aquaporin-4 (AQP4)-specific T cells and antibodies participate in the pathogenesis of neuromyelitis optica (NMO), a human central nervous system (CNS) autoimmune demyelinating disease, creation of an AQP4-targeted model with both clinical and histologic manifestations of CNS autoimmunity has proven challenging. Immunization of wild-type (WT) mice with AQP4 peptides elicited T cell proliferation, although those T cells could not transfer disease to naïve recipient mice. Recently, two novel AQP4 T cell epitopes, peptide (p) 135-153 and p201-220, were identified when studying immune responses to AQP4 in AQP4-deficient (AQP4^-/-) mice, suggesting T cell reactivity to these epitopes is normally controlled by thymic negative selection. AQP4^-/- Th17 polarized T cells primed to either p135-153 or p201-220 induced paralysis in recipient WT mice, that was associated with predominantly leptomeningeal inflammation of the spinal cord and optic nerves. Inflammation surrounding optic nerves and involvement of the inner retinal layers (IRL) were manifested by changes in serial optical coherence tomography (OCT). Here, we illustrate the approaches used to create this new in vivo model of AQP4-targeted CNS autoimmunity (ATCA), which can now be employed to study mechanisms that permit development of pathogenic AQP4-specific T cells and how they may cooperate with B cells in NMO pathogenesis.

T cells targeting neuromyelitis optica autoantigen aquaporin-4 cause paralysis and visual system injury

Aquaporin-4 (AQP4)-specific antibodies are instrumental in promoting central nervous system (CNS) tissue injury in neuromyelitis optica (NMO), yet evidence indicates that AQP4-specific T cells also have a pivotal role in NMO pathogenesis. Although considerable effort has been devoted to creation of animal models to study how AQP4-specific T cells and antibodies may cooperate in development of both clinical and histologic opticospinal inflammatory disease, the initial attempts were unsuccessful. Recently, it was discovered that T cells from AQP4-deficient (AQP4^-/-) mice recognize distinct AQP4 epitopes that were not identified previously in wild-type (WT) mice, and that donor Th17 cells from AQP4^-/- mice that target those novel epitopes could cause paralysis and visual system injury associated with opticospinal inflammation in WT recipient mice. These observations indicate that the pathogenic AQP4-specific T cell repertoire is normally controlled by negative selection. Here, we describe the advances leading to development of an animal model for aquaporin-targeted CNS autoimmunity (ATCA). This new model provides a foundation to investigate immune mechanisms that may participate in NMO pathogenesis. It should also permit preclinical testing of agents considered for treatment of NMO.

B cell repertoire expansion occurs in meningeal ectopic lymphoid tissue

Ectopic lymphoid tissues (ELT) can be found in multiple sclerosis (MS) and other organ-specific inflammatory conditions. Whether ELT in the meninges of central nervous system (CNS) autoimmune disease exhibit local germinal center (GC) activity remains unknown. In an experimental autoimmune encephalomyelitis model of CNS autoimmunity, we found activation-induced cytidine deaminase, a GC-defining enzyme, in meningeal ELT (mELT) densely populated by B and T cells. To determine GC activity in mELT, we excised meningeal lymphoid aggregates using laser capture microscopy and evaluated B cell repertoires in mELT and secondary lymphoid organs by next-generation immune repertoire sequencing. We found immunoglobulin heavy chain variable region sequences that were unique to mELT and had accumulated functionally relevant somatic mutations, together indicating localized antigen-driven affinity maturation. Our results suggest that B cells in mELT actively participate in CNS autoimmunity, which may be relevant to mELT in MS and ELT in other chronic inflammatory conditions.

Restoring immune tolerance in neuromyelitis optica: Part I

Neuromyelitis optica (NMO) and spectrum disorder (NMO/SD) represent a vexing process and its clinical variants appear to have at their pathogenic core the loss of immune tolerance to the aquaporin-4 water channel protein. This process results in a characteristic pattern of astrocyte dysfunction, loss, and demyelination that predominantly affects the spinal cord and optic nerves. Although several empirical therapies are currently used in the treatment of NMO/SD, none has been proven effective in prospective, adequately powered, randomized trials. Furthermore, most of the current therapies subject patients to long-term immunologic suppression that can cause serious infections and development of cancers. The following is the first of a 2-part description of several key immune mechanisms in NMO/SD that might be amenable to therapeutic restoration of immune tolerance. It is intended to provide a roadmap for how potential immune tolerance restorative techniques might be applied to patients with NMO/SD. This initial installment provides a background rationale underlying attempts at immune tolerization. It provides specific examples of innovative approaches that have emerged recently as a consequence of technical advances. In several autoimmune diseases, these strategies have been reduced to practice. Therefore, in theory, the identification of aquaporin-4 as the dominant autoantigen makes NMO/SD an ideal candidate for the development of tolerizing therapies or cures for this increasingly recognized disease.

Accelerated remyelination during inflammatory demyelination prevents axonal loss and improves functional recovery

Demyelination in MS disrupts nerve signals and contributes to axon degeneration. While remyelination promises to restore lost function, it remains unclear whether remyelination will prevent axonal loss. Inflammatory demyelination is accompanied by significant neuronal loss in the experimental autoimmune encephalomyelitis (EAE) mouse model and evidence for remyelination in this model is complicated by ongoing inflammation, degeneration and possible remyelination. Demonstrating the functional significance of remyelination necessitates selectively altering the timing of remyelination relative to inflammation and degeneration. We demonstrate accelerated remyelination after EAE induction by direct lineage analysis and hypothesize that newly formed myelin remains stable at the height of inflammation due in part to the absence of MOG expression in immature myelin. Oligodendroglial-specific genetic ablation of the M1 muscarinic receptor, a potent negative regulator of oligodendrocyte differentiation and myelination, results in accelerated remyelination, preventing axonal loss and improving functional recovery. Together our findings demonstrate that accelerated remyelination supports axonal integrity and neuronal function after inflammatory demyelination.

DOI:http://dx.doi.org/10.7554/eLife.18246.001

Associations between the gut microbiota and host immune markers in pediatric multiple sclerosis and controls

Background

As little is known of association(s) between gut microbiota profiles and host immunological markers, we explored these in children with and without multiple sclerosis (MS).

Methods

Children ≤18 years provided stool and blood. MS cases were within 2-years of onset. Fecal 16S rRNA gene profiles were generated on an Illumina Miseq platform. Peripheral blood mononuclear cells were isolated, and Treg (CD4⁺CD25^hiCD127^lowFoxP3⁺) frequency and CD4⁺ T-cell intracellular cytokine production evaluated by flow cytometry. Associations between microbiota diversity, phylum-level abundances and immune markers were explored using Pearson’s correlation and adjusted linear regression.

Results

Twenty-four children (15 relapsing-remitting, nine controls), averaging 12.6 years were included. Seven were on a disease-modifying drug (DMD) at sample collection. Although immune markers (e.g. Th2, Th17, Tregs) did not differ between cases and controls (p > 0.05), divergent gut microbiota associations occurred; richness correlated positively with Th17 for cases (r = +0.665, p = 0.018), not controls (r = −0.644, p = 0.061). Bacteroidetes inversely associated with Th17 for cases (r = −0.719, p = 0.008), not controls (r = +0.320, p = 0.401). Fusobacteria correlated with Tregs for controls (r = +0.829, p = 0.006), not cases (r = −0.069, p = 0.808).

Conclusions

Our observations motivate further exploration to understand disruption of the microbiota-immune balance so early in the MS course.

Electronic supplementary material

The online version of this article (doi:10.1186/s12883-016-0703-3) contains supplementary material, which is available to authorized users.

Treatment of spontaneous EAE by laquinimod reduces Tfh, B cell aggregates, and disease progression

Objective:

To evaluate the influence of oral laquinimod, a candidate multiple sclerosis (MS) treatment, on induction of T follicular helper cells, development of meningeal B cell aggregates, and clinical disease in a spontaneous B cell–dependent MS model.

Methods:

Experimental autoimmune encephalomyelitis (EAE) was induced in C57BL/6 mice by immunization with recombinant myelin oligodendrocyte glycoprotein (rMOG) protein. Spontaneous EAE was evaluated in C57BL/6 MOG p35-55–specific T cell receptor transgenic (2D2) × MOG-specific immunoglobulin (Ig)H-chain knock-in (IgH^MOG-ki [Th]) mice. Laquinimod was administered orally. T cell and B cell populations were examined by flow cytometry and immunohistochemistry.

Results:

Oral laquinimod treatment (1) reduced CD11c⁺CD4⁺ dendritic cells, (2) inhibited expansion of PD-1⁺CXCR5⁺BCL6⁺ T follicular helper and interleukin (IL)-21–producing activated CD4⁺CD44⁺ T cells, (3) suppressed B cell CD40 expression, (4) diminished formation of Fas⁺GL7⁺ germinal center B cells, and (5) inhibited development of MOG-specific IgG. Laquinimod treatment not only prevented rMOG-induced EAE, but also inhibited development of spontaneous EAE and the formation of meningeal B cell aggregates. Disability progression was prevented when laquinimod treatment was initiated after mice developed paralysis. Treatment of spontaneous EAE with laquinimod was also associated with increases in CD4⁺CD25^hiFoxp3⁺ and CD4⁺CD25⁺IL-10⁺ regulatory T cells.

Conclusions:

Our observations that laquinimod modulates myelin antigen–specific B cell immune responses and suppresses both development of meningeal B cell aggregates and disability progression in spontaneous EAE should provide insight regarding the potential application of laquinimod to MS treatment. Results of this investigation demonstrate how the 2D2 × Th spontaneous EAE model can be used successfully for preclinical evaluation of a candidate MS treatment.

Restoring immune tolerance in neuromyelitis optica: Part II

Neuromyelitis optica spectrum disorder (NMO/SD) and its clinical variants have at their core the loss of immune tolerance to aquaporin-4 and perhaps other autoantigens. The characteristic phenotype is disruption of astrocyte function and demyelination of spinal cord, optic nerves, and particular brain regions. In this second of a 2-part article, we present further perspectives regarding the pathogenesis of NMO/SD and how this disease might be amenable to emerging technologies aimed at restoring immune tolerance to disease-implicated self-antigens. NMO/SD appears to be particularly well-suited for these strategies since aquaporin-4 has already been identified as the dominant autoantigen. The recent technical advances in reintroducing immune tolerance in experimental models of disease as well as in humans should encourage quantum leaps in this area that may prove productive for novel therapy. In this part of the article series, the potential for regulatory T and B cells is brought into focus, as are new approaches to oral tolerization. Finally, a roadmap is provided to help identify potential issues in clinical development and guide applications in tolerization therapy to solving NMO/SD through the use of emerging technologies. Each of these perspectives is intended to shine new light on potential cures for NMO/SD and other autoimmune diseases, while sparing normal host defense mechanisms.

Long-term evolution of multiple sclerosis disability in the treatment era

Objective

To characterize the accrual of long‐term disability in a cohort of actively treated multiple sclerosis (MS) patients and to assess whether clinical and magnetic resonance imaging (MRI) data used in clinical trials have long‐term prognostic value.

Methods

This is a prospective study of 517 actively managed MS patients enrolled at a single center.

Results

More than 91% of patients were retained, with data ascertained up to 10 years after the baseline visit. At this last assessment, neurologic disability as measured by the Expanded Disability Status Scale (EDSS) was stable or improved compared to baseline in 41% of patients. Subjects with no evidence of disease activity (NEDA) by clinical and MRI criteria during the first 2 years had long‐term outcomes that were no different from those of the cohort as a whole. 25‐OH vitamin D serum levels were inversely associated with short‐term MS disease activity; however, these levels had no association with long‐term disability. At a median time of 16.8 years after disease onset, 10.7% (95% confidence interval [CI] = 7.2–14%) of patients reached an EDSS ≥ 6, and 18.1% (95% CI = 13.5–22.5%) evolved from relapsing MS to secondary progressive MS (SPMS).

Interpretation

Rates of worsening and evolution to SPMS were substantially lower when compared to earlier natural history studies. Notably, the NEDA 2‐year endpoint was not a predictor of long‐term stability. Finally, the data call into question the utility of annual MRI assessments as a treat‐to‐target approach for MS care. Ann Neurol 2016;80:499–510

Gut microbiome analysis in neuromyelitis optica reveals overabundance of Clostridium perfringens

T cells from neuromyelitis optica (NMO) patients, which recognize the immunodominant epitope of aquaporin‐4, exhibit Th17 polarization and cross‐react with a homologous sequence of a Clostridium perfringens adenosine triphosphate‐binding cassette transporter. Therefore, this commensal microbe might participate in NMO pathogenesis. We examined the gut microbiome by PhyloChip G3 from 16 NMO patients, 16 healthy controls (HC), and 16 multiple sclerosis patients. A significant difference in the abundance of several microbial communities was observed between NMO and HC (Adonis test, p = 0.001). Strikingly, C. perfringens was overrepresented in NMO (p = 5.24 × 10⁻⁸). These observations support a potential role for C. perfringens in NMO pathogenesis. Ann Neurol 2016;80:443–447

CNS accumulation of regulatory B cells is VLA-4-dependent

OBJECTIVE

To investigate the role of very late antigen-4 (VLA-4) on regulatory B cells (Breg) in CNS autoimmune disease.

METHODS

Experimental autoimmune encephalomyelitis (EAE) was induced in mice selectively deficient for VLA-4 on B cells (CD19cre/α4(f/f)) by immunization with myelin oligodendrocyte glycoprotein (MOG) peptide (p)35-55 or recombinant human (rh) MOG protein. B-cell and T-cell populations were examined by flow cytometry and immunohistochemistry. Breg were evaluated by intracellular IL-10 staining of B cells and, secondly, by coexpression of CD1d and CD5.

RESULTS

As previously reported, EAE was less severe in B-cell VLA-4-deficient vs control CD19cre mice when induced by rhMOG, a model that is B-cell-dependent and leads to efficient B-cell activation and antibody production. Paradoxically, B-cell VLA-4-deficient mice developed more severe clinical disease than control mice when EAE was induced with MOG p35-55, a B-cell-independent encephalitogen that does not efficiently activate B cells. Peripheral T-cell and humoral immune responses were not altered in B-cell VLA-4-deficient mice. In MOG p35-55-induced EAE, B-cell VLA-4 deficiency reduced CNS accumulation of B but not T cells. Breg were detected in the CNS of control mice with MOG p35-55-induced EAE. However, more severe EAE in B-cell VLA-4-deficient mice was associated with virtual absence of CNS Breg.

CONCLUSIONS

Our results demonstrate that CNS accumulation of Breg is VLA-4-dependent and suggest that Breg may contribute to regulation of CNS autoimmunity in situ. These observations underscore the need to choose the appropriate encephalitogen when studying how B cells contribute to pathogenesis or regulation of CNS autoimmunity.

Glatiramer acetate treatment negatively regulates type I interferon signaling

Objective:

Glatiramer acetate (GA; Copaxone), a disease-modifying therapy for multiple sclerosis (MS), promotes development of anti-inflammatory (M2, type II) monocytes that can direct differentiation of regulatory T cells. We investigated the innate immune signaling pathways that participate in GA-mediated M2 monocyte polarization.

Methods:

Monocytes were isolated from myeloid differentiation primary response gene 88 (MyD88)–deficient, Toll-IL-1 receptor domain–containing adaptor inducing interferon (IFN)–β (TRIF)–deficient, IFN-α/β receptor subunit 1 (IFNAR1)–deficient, and wild-type (WT) mice and human peripheral blood. GA-treated monocytes were stimulated with Toll-like receptor ligands, then evaluated for activation of kinases and transcription factors involved in innate immunity, and secretion of proinflammatory cytokines. GA-treated mice were evaluated for cytokine secretion and susceptibility to experimental autoimmune encephalomyelitis.

Results:

GA-mediated inhibition of proinflammatory cytokine production by monocytes occurred independently of MyD88 and nuclear factor–κB, but was blocked by TRIF deficiency. Furthermore, GA did not provide clinical benefit in TRIF-deficient mice. GA inhibited activation of p38 mitogen-activated protein kinase, an upstream regulator of activating transcription factor (ATF)–2, and c-Jun N-terminal kinase 1, which regulates IFN regulatory factor 3 (IRF3). Consequently, nuclear translocation of ATF-2 and IRF3, components of the IFN-β enhanceosome, was impaired. Consistent with these observations, GA inhibited production of IFN-β in vivo in WT mice, but did not modulate proinflammatory cytokine production by monocytes from IFNAR1-deficient mice.

Conclusion:

Our results demonstrate that GA inhibits the type I IFN pathway in M2 polarization of monocytes independently of MyD88, providing an important mechanism connecting innate and adaptive immune modulation in GA therapy and valuable insight regarding its potential use with other MS treatments.

Vitamin D in clinically isolated syndrome: evidence for possible neuroprotection

BACKGROUND AND PURPOSE

Vitamin D status has been associated with inflammatory activity in multiple sclerosis (MS), but it is not known if it is associated with gray matter volume, the loss of which predicts long-term disability in MS. The association of vitamin D levels with brain volume measures and inflammatory activity in patients with clinically isolated syndrome (CIS) was investigated.

METHODS

In the phase 2 CIS trial of atorvastatin, 25-hydroxyvitamin D levels were evaluated for their age-adjusted associations with normalized gray matter and brain parenchymal volumes on brain magnetic resonance imaging (MRI). The relationships between 25-hydroxyvitamin D levels and clinical and MRI measures of inflammatory activity were also assessed.

RESULTS

In 65 patients in this substudy, each 25 nmol/l higher 25-hydroxyvitamin D level was associated with 7.8 ml higher gray matter volume (95% confidence interval 1.0, 14.6, P = 0.025). There was a tendency for an inverse association of average 25-hydroxyvitamin D levels and the composite end-point of ≥3 new brain T2 lesions or ≥1 relapse within a year (odds ratio per 25 nmol/l higher 25-hydroxyvitamin D level 0.66, 95% confidence interval 0.41, 1.08, P = 0.096).

CONCLUSIONS

Vitamin D status may impact neurodegeneration after CIS, although these results should be replicated in a second study. If confirmed in clinical trials, vitamin D supplementation may reduce long-term disability.

The ubiquitin-modifying enzyme A20 restricts ubiquitination of the kinase RIPK3 and protects cells from necroptosis

A20 is an anti-inflammatory protein linked to multiple human diseases; however, the mechanisms by which A20 prevents inflammatory disease are incompletely defined. We found that A20-deficient T cells and fibroblasts were susceptible to caspase-independent and kinase RIPK3-dependent necroptosis. Global deficiency in RIPK3 significantly restored the survival of A20-deficient mice. A20-deficient cells exhibited exaggerated formation of RIPK1-RIPK3 complexes. RIPK3 underwent physiological ubiquitination at Lys5 (K5), and this ubiquitination event supported the formation of RIPK1-RIPK3 complexes. Both the ubiquitination of RIPK3 and formation of the RIPK1-RIPK3 complex required the catalytic cysteine of A20's deubiquitinating motif. Our studies link A20 and the ubiquitination of RIPK3 to necroptotic cell death and suggest additional mechanisms by which A20 might prevent inflammatory disease.

B lymphocytes in neuromyelitis optica

Neuromyelitis optica (NMO) is an inflammatory autoimmune disorder of the CNS that predominantly affects the spinal cord and optic nerves. A majority (approximately 75%) of patients with NMO are seropositive for autoantibodies against the astrocyte water channel aquaporin-4 (AQP4). These autoantibodies are predominantly IgG1, and considerable evidence supports their pathogenicity, presumably by binding to AQP4 on CNS astrocytes, resulting in astrocyte injury and inflammation. Convergent clinical and laboratory-based investigations have indicated that B cells play a fundamental role in NMO immunopathology. Multiple mechanisms have been hypothesized: AQP4 autoantibody production, enhanced proinflammatory B cell and plasmablast activity, aberrant B cell tolerance checkpoints, diminished B cell regulatory function, and loss of B cell anergy. Accordingly, many current off-label therapies for NMO deplete B cells or modulate their activity. Understanding the role and mechanisms whereby B cells contribute to initiation, maintenance, and propagation of disease activity is important to advancing our understanding of NMO pathogenesis and developing effective disease-specific therapies.

B-cell very late antigen-4 deficiency reduces leukocyte recruitment and susceptibility to central nervous system autoimmunity

Natalizumab, which binds very late antigen‐4 (VLA‐4), is a potent therapy for multiple sclerosis (MS). Studies have focused primarily upon its capacity to interfere with T‐cell migration into the central nervous system (CNS). B cells are important in MS pathogenesis and express high levels of VLA‐4. Here, we report that the selective inhibition of VLA‐4 expression on B cells impedes CNS accumulation of B cells, and recruitment of Th17 cells and macrophages, and reduces susceptibility to experimental autoimmune encephalomyelitis. These results underscore the importance of B‐cell VLA‐4 expression in the pathogenesis of CNS autoimmunity and provide insight regarding mechanisms that may contribute to the benefit of natalizumab in MS, as well as candidate therapeutics that selectively target B cells. Ann Neurol 2015;77:902–908

Update on the autoimmune pathology of multiple sclerosis: B-cells as disease-drivers and therapeutic targets

BACKGROUND

Collectively, research on the role of B-cells in the pathogenesis of multiple sclerosis (MS) illustrates how translational medicine has given rise to promising therapeutic approaches for one of the most debilitating chronic neurological diseases in young adults. First described in 1935, the experimental autoimmune/allergic encephalomyelitis model is a key animal model that has provided the foundation for important developments in targeted therapeutics.

SUMMARY

While additional B-cell therapies for MS are presently being developed by the pharmaceutical industry, much remains to be understood about the role played by B-cells in MS. The goal of this review is to summarize how B-cells may contribute to MS pathogenesis and thereby provide a basis for understanding why B-cell depletion is so effective in the treatment of this disease. Key Messages: B-cells are key players in the pathogenesis of MS, and their depletion via B-cell-targeted therapy ameliorates disease activity.

CLINICAL IMPLICATIONS

In 2008, data from the first CD20-targeting B-cell depleting therapeutic trials using rituximab in MS were published. Since then, there has been a large body of evidence demonstrating the effectiveness of B-cell depletion mediated via anti-CD20 antibodies. Intense research efforts focusing on the immunopathological relevance of B-cells has gained significant momentum and given rise to a constellation of promising therapeutic agents for this complex B-cell-driven disease, including novel anti-CD20 antibodies, as well as agents targeting CD19 and BAFF-R.

Reduction of CD8(+) T lymphocytes in multiple sclerosis patients treated with dimethyl fumarate

Objective:

To evaluate the influence of dimethyl fumarate (DMF, Tecfidera) treatment of multiple sclerosis (MS) on leukocyte and lymphocyte subsets.

Methods:

Peripheral blood leukocyte and lymphocyte subsets, including CD3⁺, CD4⁺, and CD8⁺ T cells; CD19⁺ B cells; and CD56⁺ natural killer (NK) cells, were obtained at baseline and monitored at 3 months, 6 months, and 12 months after initiation of DMF treatment.

Results:

Total leukocyte and lymphocyte counts diminished after 6 months of DMF therapy. At 12 months, lymphocyte counts had decreased by 50.1% (p < 0.0001) and were below the lower limit of normal (LLN) in one-half of patients. CD3⁺ T lymphocyte counts fell by 44.2% (p < 0.0001). Among subsets, CD8⁺ T cell counts declined by 54.6% (p < 0.0001), whereas CD4⁺ T cell counts decreased by 39.2% (p = 0.0006). This disproportionate reduction of CD8⁺ T cells relative to CD4⁺ T cells was significant (p = 0.007) and was reflected by a 35.5% increase in the CD4/CD8 ratio (p = 0.007). A majority of CD8⁺ T cell counts, but not CD4⁺ T cell counts, were below the LLN even when total lymphocyte counts were greater than 500 cells/μL. CD19⁺ B cell counts were reduced by 37.5% (p = 0.035). Eosinophil levels decreased by 54.1% (p = 0.006), whereas levels of neutrophils, monocytes, basophils, and NK cells were not significantly altered.

Conclusion:

Subsets of peripheral blood leukocytes and lymphocytes are differentially affected by DMF treatment of MS. Reduction of CD8⁺ T cells is more pronounced than that of CD4⁺ T cells. These findings may have implications for cell-mediated antiviral immunity during DMF treatment.

Does MOG Ig-positive AQP4-seronegative opticospinal inflammatory disease justify a diagnosis of NMO spectrum disorder?

While neuromyelitis optica (NMO) immunoglobulin (Ig) G is considered the hallmark serologic marker of NMO, its association is not absolute, as NMO IgG is not detected in approximately one-fourth of the patients diagnosed with NMO spectrum disorder (NMOSD). Thus, the recent discovery that antibodies to myelin oligodendrocyte glycoprotein (MOG) are detected in some NMO IgG-seronegative patients manifesting clinical and neuroimaging signs of NMO or NMOSD has created tremendous excitement. However, it may be premature to classify this subgroup as NMOSD. NMO is considered an autoimmune astrocytopathy, and aquaporin-4 (AQP4), expressed on astrocytes, is recognized as the target autoantigen of NMO IgG. As its name denotes, MOG is produced by oligodendrocytes, CNS myelin-producing cells, and MOG is well-recognized as one of the candidate autoantigens in multiple sclerosis (MS) and acute disseminated encephalomyelitis (ADEM). Thus, is it possible that the clinical NMOSD-like phenotype associated with MOG-specific antibodies represents a variant of opticospinal MS or ADEM but not AQP4 autoimmunity or NMOSD? Whether this MOG-Ig positive AQP4-seronegative phenotype should be classified as NMOSD, opticospinal MS, or a unique entity is not simply a theoretical question but rather has practical implications for patients, their physicians, insurance carriers, and clinical investigators conducting NMO treatment trials.

Precision medicine in chronic disease management: The multiple sclerosis BioScreen

We present a precision medicine application developed for multiple sclerosis (MS): the MS BioScreen. This new tool addresses the challenges of dynamic management of a complex chronic disease; the interaction of clinicians and patients with such a tool illustrates the extent to which translational digital medicine-that is, the application of information technology to medicine-has the potential to radically transform medical practice. We introduce 3 key evolutionary phases in displaying data to health care providers, patients, and researchers: visualization (accessing data), contextualization (understanding the data), and actionable interpretation (real-time use of the data to assist decision making). Together, these form the stepping stones that are expected to accelerate standardization of data across platforms, promote evidence-based medicine, support shared decision making, and ultimately lead to improved outcomes.