University of California, San Francisco
Neurology

Author Of 1 Presentation

Microbiome Oral Presentation

PS10.05 - Gut dysbiosis in neuromyelitis optica promotes CNS autoimmunity

Speakers
Presentation Number
PS10.05
Presentation Topic
Microbiome
Lecture Time
10:09 - 10:21

Abstract

Background

Neuromyelitis optica (NMO) is a severe demyelinating disease of the central nervous system (CNS) causing irreversible neurological damage. Initial analyses of gut microbiota in NMO, multiple sclerosis and healthy controls (HHC) revealed dysbiosis in the NMO group, suggesting that the gut microbiome may regulate inflammatory responses

Objectives

We hypothesized that gut microbiota from NMO patients may participate and promote inflammatory responses in NMO pathogenesis.

Methods

Wild-type (WT) C57BL/6 germ-free mice were colonized with fecal samples from one untreated NMO patient (n = 10), one household HC (HHC) (n = 9) or vehicle (n = 13) for five weeks and then examined for susceptibility to MOG p35-55-induced experimental autoimmune encephalomyelitis (EAE) for 30 days post immunization. Upon termination of the study, lymphocytes from spleen, lamina propria of small (LP-SI) and large (LP-LI) intestine, mesenteric lymph nodes (MLN), Peyer’s patches (PP), brain, and spinal cord were examined for the expression of IL-17, IFN-γ, Foxp3, CD25, RORγt and Helios.

Results

In comparison to the mean EAE score of the vehicle group (1.9 ± 0.3), severity was greater (p ≤ 0.01) in mice colonized with fecal microbiota from NMO (3.1 ± 0.8) and HHC (2.7 ± 0.7). The mean clinical score of mice colonized with NMO gut microbiota was significantly greater than mice colonized with gut microbiota from HHC or vehicle (p ≤ 0.001). The frequency of CD4+Foxp3+CD25+ cells was decreased in LP-SI, LP-LI, PP and MLN compartments in NMO and HHC compared with vehicle group (p ≤ 0.01). CD4+Foxp3+Helios+ (another regulatory T cell subpopulation) was significantly decreased in MLN and LP-SI of NMO and HHC compared to vehicle group (P ≤ 0.01).

Conclusions

Our data suggest that NMO fecal microbiota increases EAE susceptibility. Reduction in frequency of Tregs in the gut of mice colonized with NMO fecal material may contribute to EAE exacerbation. Further analysis of microbiota and lymphocyte populations in mice colonized with fecal material from NMO and HHC samples are needed. Results from our ongoing study should provide valuable insight regarding the potential role of gut microbiota in NMO.

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Author Of 1 Presentation

Disease Modifying Therapies – Mechanism of Action Poster Presentation

P0325 - Effect of ozanimod on proportions of leukocyte subsets in patients with relapsing multiple sclerosis (ID 979)

Speakers
Presentation Number
P0325
Presentation Topic
Disease Modifying Therapies – Mechanism of Action

Abstract

Background

Ozanimod is a sphingosine 1-phosphate receptor 1 and 5 modulator that blocks the capacity of lymphocytes to egress from lymphoid tissue, reducing the number of lymphocytes in peripheral blood. The mechanism by which ozanimod exerts therapeutic effects in multiple sclerosis is unknown, but may involve reduction of lymphocyte migration into the central nervous system.

Objectives

To characterize the phenotype of circulating leukocytes in relapsing multiple sclerosis (RMS) in participants treated with ozanimod.

Methods

In a phase 1, open-label, pharmacokinetic/pharmacodynamic study, 24 participants with RMS were randomized to oral ozanimod 0.46 (n=13) or 0.92 mg/d (n=11) [equivalent to ozanimod HCl 0.5 or 1 mg] for ~12 weeks, including an initial 7-d dose escalation (0.23 mg/d x 4d + 0.46 mg/d x 3d). Key exclusion criteria were active infection, history of chronic infections or immunodeficiency, recent live vaccination, previous lymphocyte-depleting or immunosuppressant therapy, and absolute lymphocyte count <1.0 × 109/L. Exploratory analyses used flow cytometry to characterize proportional changes from baseline in leukocyte subsets on days 28, 56, and 85 in total peripheral blood mononuclear cells (PBMC) and total T cells. Proportional change from baseline is reported using descriptive statistics.

Results

Ozanimod was associated with dose-dependent decreases in absolute numbers of CD4+ and CD8+ T cells. Within the PBMC population, ozanimod was associated with a minimal increase in the proportion of CD8+ TEMRA cells (ozanimod 0.92 mg only) and no change in CD8+ effector memory T (TEM) cells. A decrease in the proportion of CD4+ and CD8+ naive and central memory T (TCM) cells and CD4+ TEM cells was evident. Within the total T cell population, ozanimod was associated with an increase in the proportion of CD4+ TEM cells (ozanimod 0.92 mg only) and CD8+ TEM and TEMRA cells. A decrease in the proportion of CD4+ naive (ozanimod 0.92 mg only) and CD8+ naive cells was observed; CD4+ and CD8+ TCM cells were minimally affected. Changes from baseline were more pronounced with ozanimod 0.92 mg than with ozanimod 0.46 mg.

Conclusions

During ozanimod treatment, the relative frequencies of circulating cell types within total PBMCs and within the remaining T cell population were altered. These shifts in circulating leukocyte proportions support the hypothesis that although ozanimod inhibits trafficking of some subsets of lymphocytes, the remaining circulating cells are still poised to provide immune surveillance.

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