Connexin 30 Deficiency Ameliorates Disease Progression at the Early Phase in a Mouse Model of Amyotrophic Lateral Sclerosis by Suppressing Glial Inflammation.

Connexin 30 (Cx30), which forms gap junctions between astrocytes, regulates cell adhesion and migration, and modulates glutamate transport. Cx30 is upregulated on activated astroglia in central nervous system inflammatory lesions, including spinal cord lesions in mutant superoxide dismutase 1 (mSOD1) transgenic amyotrophic lateral sclerosis (ALS) model mice. Here, we investigated the role of Cx30 in mSOD1 mice. Cx30 was highly expressed in the pre-onset stage in mSOD1 mice. mSOD1 mice with knockout (KO) of the Cx30 gene (Cx30KO-mSOD1 mice) showed delayed disease onset and tended to have an extended survival period (log-rank, p = 0.09). At the progressive and end stages of the disease, anterior horn cells were significantly preserved in Cx30KO-mSOD1 mice. In lesions of these mice, glial fibrillary acidic protein/C3-positive inflammatory astroglia were decreased. Additionally, the activation of astrocytes in Cx30KO-mSOD1 mice was reduced compared with mSOD1 mice by gene expression microarray. Furthermore, expression of connexin 43 at the pre-onset stage was downregulated in Cx30KO-mSOD1 mice. These findings suggest that reduced expression of astroglial Cx30 at the early disease stage in ALS model mice protects neurons by attenuating astroglial inflammation.

Hopkins syndrome following the first episode of bronchial asthma associated with enterovirus D68: a case report.

BACKGROUND: Hopkins syndrome (HS) is a rare disorder presenting with acute flaccid paralysis of the limbs following an asthma attack. Neurologists encounter a diagnostic challenge if patients without a history of bronchial asthma develop neurologic features mimicking HS following acute respiratory distress. We report a case of HS occurring after a first episode of bronchial asthma associated with enterovirus D68 infection. CASE PRESENTATION: A 5-year-old girl developed acute respiratory distress. On the fourth hospital day, both her legs became paralyzed except for slight muscle contraction in the right lower limb. Tendon reflexes in the lower limbs were diminished and there was a positive Babinski sign on the right. Sensation was normal in all modalities, and there was no uro-rectal disturbance. Spinal magnetic resonance imaging identified T2-hyperintense lesions with spinal cord edema, mainly involving the bilateral T11 to L1 anterior horns, with left side dominance extending to the left posterior horn. The neurological and neuro-radiological findings of our case were suggestive of HS; however, she had no history of bronchial asthma. An acetylcholine inhalation challenge eventually proved the presence of reversible airway hyper-responsiveness, allowing us to diagnose HS. We identified enterovirus D68 in the patient's intratracheal aspirates using a sensitive polymerase chain reaction assay. Intravenous immunoglobulin administrations at 2 g/kg2 for 5 consecutive days were repeated every month up to four times. After these treatments, the muscle strength of her right lower limb slightly improved while her left lower leg remained completely paralyzed. CONCLUSION: This case emphasizes the importance of provocation tests to reveal the presence of airway hyper-responsiveness when a child shows neurological signs mimicking HS following acute respiratory distress. Furthermore, the present case suggests a possible link between HS and acute flaccid paralysis following lower respiratory tract infection by enterovirus D68.

A nationwide survey of combined central and peripheral demyelination in Japan.

OBJECTIVES: To clarify the clinical features of combined central and peripheral demyelination (CCPD) via a nationwide survey. METHODS: The following characteristics were used to define CCPD: T2 high-signal intensity lesions in the brain, optic nerves or spinal cord on MRI, or abnormalities on visual-evoked potentials; conduction delay, conduction block, temporal dispersion or F-wave abnormalities suggesting demyelinating neuropathy based on nerve conduction studies; exclusion of secondary demyelination. We conducted a nationwide survey in 2012, sending questionnaires to 1332 adult and paediatric neurology institutions in Japan. RESULTS: We collated 40 CCPD cases, including 29 women. Age at onset was 31.7±14.1 years (mean±SD). Sensory disturbance (94.9%), motor weakness (92.5%) and gait disturbance (79.5%) were common. Although cerebrospinal fluid protein levels were increased in 82.5%, oligoclonal IgG bands and elevated IgG indices were detected in 7.4% and 18.5% of cases, respectively. Fifteen of 21 patients (71.4%) had abnormal visual-evoked potentials. Antineurofascin 155 antibodies were positive in 5/11 (45.5%). Corticosteroids, intravenous immunoglobulins and plasmapheresis resulted in an 83.3%, 66.7% and 87.5% improvement, respectively, whereas interferon-ß was effective in only 10% of cases. CCPD cases with simultaneous onset of central nervous system (CNS) and peripheral nervous system (PNS) involvement exhibited greater disability, but less recurrence and more frequent extensive cerebral and spinal cord MRI lesions compared to those with temporarily separated onset, whereas optic nerve involvement was more common in the latter. CONCLUSIONS: CCPD shows different characteristics from classical demyelinating diseases, and distinctive features exist between cases with simultaneous and temporarily separated onset of CNS and PNS involvement.

Mesenchymal stem cells as a source of Schwann cells: their anticipated use in peripheral nerve regeneration.

Schwann cells form myelin, sustain axons and provide the microenvironment for nerve fibers, thereby playing a key role in the peripheral nervous system (PNS). Schwann cells also provide support for the damaged PNS by producing factors that strongly promote axonal regrowth and contribute to remyelination, which is crucial for the recovery of neural function. These advantages are not confined to the PNS and also apply to the central nervous system. Many diseases, including peripheral nerve injury, neuropathy, multiple sclerosis and spinal cord injury, are targets for Schwann cell therapy. The collection of Schwann cells, however, causes new damage to other peripheral nerve segments. Furthermore, the doubling time of Schwann cells is not very fast, and thus adequate amounts of Schwann cells for clinical use cannot be collected within a reasonable amount of time. Mesenchymal stem cells, which are highly proliferative, are easily accessible from various types of mesenchymal tissues, such as the bone marrow, umbilical cord and fat tissue. Because these cells have the ability to cross oligolineage boundaries between mesodermal to ectodermal lineages, they are capable of differentiating into Schwann cells with step-by-step cytokine stimulation. In this review, we summarize the properties of mesenchymal stem cell-derived Schwann cells, which are comparable to authentic Schwann cells, and discuss future perspectives.

Multilineage-differentiating stress-enduring (Muse) cells are a primary source of induced pluripotent stem cells in human fibroblasts.

The stochastic and elite models have been proposed for the mechanism of induced pluripotent stem (iPS) cell generation. In this study we report a system that supports the elite model. We previously identified multilineage-differentiating stress-enduring (Muse) cells in human dermal fibroblasts that are characterized by stress tolerance, expression of pluripotency markers, self-renewal, and the ability to differentiate into endodermal-, mesodermal-, and ectodermal-lineage cells from a single cell. They can be isolated as stage-specific embryonic antigen-3/CD105 double-positive cells. When human fibroblasts were separated into Muse and non-Muse cells and transduced with Oct3/4, Sox2, Klf4, and c-Myc, iPS cells were generated exclusively from Muse cells but not from non-Muse cells. Although some colonies were formed from non-Muse cells, they were unlike iPS cells. Furthermore, epigenetic alterations were not seen, and some of the major pluripotency markers were not expressed for the entire period during iPS cell generation. These findings were confirmed further using cells transduced with a single polycistronic virus vector encoding all four factors. The results demonstrate that in adult human fibroblasts a subset of preexisting adult stem cells whose properties are similar in some respects to those of iPS cells selectively become iPS cells, but the remaining cells make no contribution to the generation of iPS cells. Therefore this system seems to fit the elite model rather than the stochastic model.

Distinct retinal reflectance spectra from retinal hyperspectral imaging in Parkinson's disease.

BACKGROUND: Recent developments in the retinal hyperspectral imaging method have indicated its potential in addressing challenges posed by neurodegenerative disorders, such as Alzheimer's disease. This human clinical study is the first to assess reflectance spectra obtained from this imaging as a tool for diagnosing patients with Parkinson's disease (PD). METHODS: Retinal hyperspectral imaging was conducted on a total of 40 participants, including 20 patients with PD and 20 controls. Following preprocessing, retinal reflectance spectra were computed for the macular retina defined by four rectangular regions. Linear discriminant analysis classifiers underwent training to discern patients with PD from control participants. To assess the performance of the selected features, nested leave-one-out cross-validation was employed using machine learning. The indicated values include the area under the curve (AUC) and the corresponding 95% confidence interval (CI). RESULTS: Retinal reflectance spectra of PD patients exhibited variations in the spectral regions, particularly at shorter wavelengths (superonasal retina, wavelength < 490 nm; inferonasal retina, wavelength < 510 nm) when compared to those of controls. Retinal reflectance spectra yielded an AUC of 0.60 (95% CI: 0.43-0.78) and 0.60 (95% CI: 0.43-0.78) for the superonasal and inferonasal retina, respectively, distinguishing individuals with and without PD. CONCLUSION: Reflectance spectra obtained from retinal hyperspectral imaging tended to decrease at shorter wavelengths across a broad spectral range in PD patients. Further investigations building upon these preliminary findings are imperative to focus on the retinal spectral signatures associated with PD pathological hallmarks, including α-synuclein.

Treatment with basic fibroblast growth factor-incorporated gelatin hydrogel does not exacerbate mechanical allodynia after spinal cord contusion injury in rats.

UNLABELLED: Besides stimulating angiogenesis or cell survival, basic fibroblast growth factor (bFGF) has the potential for protecting neurons in the injured spinal cord. OBJECTIVE: To investigate the effects of a sustained-release system of bFGF from gelatin hydrogel (GH) in a rat spinal cord contusion model. METHODS: Adult female Sprague-Dawley rats were subjected to a spinal cord contusion injury at the T10 vertebral level using an IH impactor (200 kdyn). One week after contusion, GH containing bFGF (20 µg) was injected into the lesion epicenter (bFGF - GH group). The GH-only group was designated as the control. Locomotor recovery was assessed over 9 weeks by Basso, Beattie, Bresnahan rating scale, along with inclined plane and Rota-rod testing. Sensory abnormalities in the hind paws of all the rats were evaluated at 5, 7, and 9 weeks. RESULTS: There were no significant differences in any of the motor assessments at any time point between the bFGF - GH group and the control GH group. The control GH group showed significantly more mechanical allodynia than did the group prior to injury. In contrast, the bFGF - GH group showed no statistically significant changes of mechanical withdrawal thresholds compared with pre-injury. CONCLUSION: Our findings suggest that bFGF-incorporated GH could have therapeutic potential for alleviating mechanical allodynia following spinal cord injury.

Early and extensive alterations of glial connexins, distal oligodendrogliopathy type demyelination, and nodal/paranodal pathology are characteristic of multiple system atrophy.

The pathological hallmark of multiple system atrophy (MSA) is aberrant accumulation of phosphorylated α-synuclein in oligodendrocytes, forming glial cytoplasmic inclusions (GCIs). Extensive demyelination occurs particularly in the olivopontocerebellar and striatonigral pathways, but its precise mechanism remains elusive. Glial connexins (Cxs), which form gap junction channels between astrocytes and oligodendrocytes, play critical roles in myelin maintenance, and have not been studied in MSA. Therefore, we immunohistochemically investigated glial Cx changes in the cerebellar afferent fibers in 15 autopsied patients with MSA. We classified demyelinating lesions into three stages based on Klüver-Barrera staining: early (Stage I), intermediate (Stage II), and late (Stage III) stages showing subtle, moderate, and severe myelin reduction, respectively. Myelin-associated glycoprotein, but not myelin oligodendrocyte glycoprotein, was preferentially decreased in Stage I, suggesting distal oligodendrogliopathy type demyelination. Accumulation of phosphorylated α-synuclein in oligodendrocytes was frequently seen in Stage I but less frequently observed in Stages II and III. Tubulin polymerization-promoting protein (TPPP/p25α)-positive oligodendrocytes were preserved in Stage I but successively decreased in Stages II and III. Even at Stage I, Cx32 was nearly absent from myelin, despite the relative preservation of other nodal proteins, such as neurofascin, claudin-11/oligodendrocyte-specific protein, and contactin-associated protein 1, which successively decreased in the later stages. Cx32 was re-distributed in the oligodendrocyte cytoplasm and co-localized with GCIs. Cx47 gradually decreased at the oligodendrocyte surface in a stage-dependent manner but was not co-localized with GCIs. Astrocytic Cx43 was down-regulated in Stage I but up-regulated in Stages II and III, reflecting astrogliosis. Cx43/Cx47 gap junctions significantly decreased from Stage I to III. Activated microglia/macrophages and T cells infiltrated in Stage I rather than Stages II and III. Therefore, early and extensive alterations of glial Cxs, particularly Cx32 loss, occur in MSA and may accelerate distal oligodendrogliopathy type demyelination and nodal/paranodal dysfunction through disruption of inter-glial communication.

High-dose ubiquinol supplementation in multiple-system atrophy: a multicentre, randomised, double-blinded, placebo-controlled phase 2 trial.

Background: Functionally impaired variants of COQ2, encoding an enzyme in biosynthesis of coenzyme Q10 (CoQ10), were found in familial multiple system atrophy (MSA) and V393A in COQ2 is associated with sporadic MSA. Furthermore, reduced levels of CoQ10 have been demonstrated in MSA patients. Methods: This study was a multicentre, randomised, double-blinded, placebo-controlled phase 2 trial. Patients with MSA were randomly assigned (1:1) to either ubiquinol (1500 mg/day) or placebo. The primary efficacy outcome was the change in the unified multiple system atrophy rating scale (UMSARS) part 2 at 48 weeks. Efficacy was assessed in all patients who completed at least one efficacy assessment (full analysis set). Safety analyses included patients who completed at least one dose of investigational drug. This trial is registered with UMIN-CTR (UMIN000031771), where the drug name of MSA-01 was used to designate ubiquinol. Findings: Between June 26, 2018, and May 27, 2019, 139 patients were enrolled and randomly assigned to the ubiquinol group (n = 69) or the placebo group (n = 70). A total of 131 patients were included in the full analysis set (63 in the ubiquinol group; 68 in the placebo group). This study met the primary efficacy outcome (least square mean difference in UMSARS part 2 score (-1.7 [95% CI, -3.2 to -0.2]; P = 0.023)). The ubiquinol group also showed better secondary efficacy outcomes (Barthel index, Scale for the Assessment and Rating of Ataxia, and time required to walk 10 m). Rates of adverse events potentially related to the investigational drug were comparable between ubiquinol (n = 15 [23.8%]) and placebo (n = 21 [30.9%]). Interpretation: High-dose ubiquinol was well-tolerated and led to a significantly smaller decline of UMSARS part 2 score compared with placebo. Funding: Japan Agency for Medical Research and Development.

[A case of sudden-onset transverse myelopathy suspected to be caused by fibrocartilaginous embolism].

A 44-year-old male was admitted to our hospital because of sudden weakness and sensory loss in both legs following left scapular pain. He had a history of lower back pain but no vascular risk factors. Neurological examination on admission revealed flaccid paraplegia, a loss of both pinprick and vibratory sensations below the Th6 level, and bladder and rectal disturbances. Tendon reflexes were absent in both lower limbs. Diffusion-weighted imaging performed 5 hours after onset revealed an extensive high-intensity lesion at the Th2-6 spine levels, accompanied by a vague high intensity on T2-weighted images. CT angiography showed no abnormalities of the aorta or the artery of Adamkiewicz. Laboratory test results were normal and there was no evidence of coagulopathy. Autoantibodies, including anti-aquaporin-4 and anti-myelin oligodendrocyte glycoprotein antibodies, were negative. The cerebrospinal fluid test was normal. The lesion had expanded to the whole thoracic cord and was markedly swollen on T2-weighted imaging at 5 days after onset. Immunotherapies, including intravenous methylprednisolone pulse therapy and plasma exchange, were ineffective. Although there was no evidence of any source of embolism, we found degenerative calcified changes in the fibrocartilage of the intervertebral discs, with Schmorl's nodes in the thoracic spines. We clinically diagnosed the patient with spinal cord infarction caused by fibrocartilaginous embolism. He developed deep vein thrombosis and was treated with edoxaban. His neurological symptoms did not improve during 55 days of hospitalization. In a case with sudden-onset myelopathy, fibrocartilaginous embolism should be considered.

Early decrease in intermediate monocytes in peripheral blood is characteristic of multiple system atrophy-cerebellar type.

To identify biomarkers for multiple system atrophy-cerebellar type (MSA-C), we used flow cytometry to measure surface marker expression of peripheral blood monocytes from patients with MSA-C or hereditary spinocerebellar degeneration (hSCD) and from healthy controls (HCs). The percentage of intermediate monocytes was significantly lower in MSA-C patients than in hSCD patients and HCs and showed significant positive correlations with disease duration and unified MSA rating scale scores. The percentage of CD62L+ intermediate monocytes was significantly lower in MSA-C patients than in hSCD patients and HCs. Early decrease of peripheral blood intermediate monocytes is characteristic of MSA-C and is a biomarker.

MOG antibody disease manifesting as progressive cognitive deterioration and behavioral changes with primary central nervous system vasculitis.

We report a 60-year-old male with anti-myelin oligodendrocyte glycoprotein (MOG) antibody who developed progressive cognitive deterioration and behavioral changes, with no other focal signs, over 9 months. MRI showed numerous T2-hyperintense lesions with partial contrast enhancement in white and grey matter of cerebrum, cerebellum and spinal cord. A brain biopsy revealed perivascular inflammatory cell infiltration, disturbed vascular continuity and no demyelination, indicative of a lymphocytic pattern of primary CNS vasculitis (PCNSV). Contrast enhancement disappeared after immunotherapy; however, cognitive impairment was not improved. Neurologists should note that MOG antibody disease can present as immunotherapy-resistant progressive cognitive impairment with PCNSV-like histopathology.

[Case of eosinophilic myositis in continuum from localized nodular myositis].

We report a 72-year-old man with eosinophilic myositis (EM). At age 71 he noticed a painful nodule in his left calf. A biopsy (first biopsy) showed marked infiltration of mononucleated cells and necrotic muscle fibers. Several phagocytosed fibers were also seen. He was diagnosed as having myositis. The painful nodule disappeared spontaneously. At age 72, he again had a painful nodule, but this time in his right calf; again, this disappeared spontaneously on the first admission. Just after discharge, he noted painful nodules in the left thigh and right anterior tibial muscles and was again admitted (second admission). Neurological examination revealed mild proximal-dominant weakness in all four extremities but no other abnormalities. Laboratory studies showed elevated creatine kinase (CK) level (38,803 U/l; normal 62-287) and positive Jo-1 antibody, but no eosinophilia. Needle electromyography of the limb muscles showed myogenic patterns. Magnetic resonance imaging of the lower limbs demonstrated several T2-high and gadolinium (Gd)-enhanced lesions. Muscle biopsy (second biopsy) from the left quadriceps femoris showed marked infiltration of eosinophils; he was diagnosed as having EM. Administration of prednisolone was initiated at 60 mg/day and then gradually tapered. After starting treatment with steroids, his muscle weakness gradually ameliorated, CK level dramatically decreased, and the nodules disappeared. Clinically, the patient had developed localized nodular myositis (LNM), but pathologically it was EM without peripheral blood eosinophilia and positive Jo-1 antibody that is occasionally found in polymyositis (PM). Thus, this patient demonstrated overlapping characteristics of EM, LNM, and possibly PM, suggesting that a common mechanism underlay these conditions. As discussed, the involvement of eosinophils in three inflammatory myopathies was indicated.

Exacerbation of chronic inflammatory demyelinating polyradiculoneuropathy during interferonbeta-1b therapy in a patient with childhood-onset multiple sclerosis.

Interferonbeta-1b (IFNbeta-1b) is commonly used for relapsing-remitting multiple sclerosis (MS). We report a 23-year-old woman with childhood onset relapsing-remitting MS treated with IFNbeta-1b who developed overt chronic inflammatory demyelinating polyradiculoneuropathy (CIDP) immediately after therapy. A baseline conduction study before IFNbeta-1b therapy revealed decreased motor conduction velocities and prolonged F wave latencies in several nerves, but there was no neurological sign indicating neuropathy. The existence of subclinical demyelinating neuropathy before IFNbeta-1b treatment was suggested, although the clinical criteria for CIDP were unfulfilled. Following two months of IFNbeta-1b therapy, numbness of her right upper and lower limbs progressively worsened and all tendon reflexes were depressed. Electrophysiologically, F waves were not evoked in any limbs except for the left ulnar and tibial nerves, which showed marked prolongation of F wave latencies. Moreover, subclinical hyperthyroidism developed in association with high titers of anti-thyroglobulin and antithyroid peroxydase antibodies, which were negative before IFNbeta-1b therapy. These findings indicated that peripheral demyelination worsened at the nerve roots after IFNbeta-1b therapy. In addition to the development of autoimmune thyroid disease, the patient now fulfilled the criteria for probable CIDP. Along with the results of a previous report demonstrating IFNbeta-induced CIDP development in patients with childhood MS, this case underscores IFNbeta as a potential risk factor for CIDP in patients with childhood onset MS.

Decreased serum vitamin D levels in Japanese patients with multiple sclerosis.

Data regarding vitamin D in multiple sclerosis (MS) in Asia are limited. We investigated whether Japanese MS patients show decreased serum 25-hydroxyvitamin D [25(OH)D], 1,25-dihydroxyvitamin D [1,25(OH)2D], and vitamin D-binding protein (DBP) during winter. Mean serum 25(OH)D and 1,25(OH)2D levels were significantly lower in MS patients than in controls. There were no significant differences in serum 25(OH)D, 1,25(OH)2D, and DBP levels between patients or between controls from northern Japan (Hokkaido) and southern Japan (Kyushu). Serum vitamin D levels were low in Japanese MS patients but did not differ in patients from northern and southern Japan.

Characterization of IgG4 anti-neurofascin 155 antibody-positive polyneuropathy.

OBJECTIVE: To investigate anti-neurofascin 155 (NF155) antibody-positive chronic inflammatory demyelinating polyneuropathy (CIDP). METHODS: Sera from 50 consecutive CIDP patients diagnosed in our clinic, 32 patients with multiple sclerosis, 40 patients with other neuropathies including 26 with Guillain-Barré syndrome (GBS)/Fisher syndrome, and 30 healthy controls were measured for anti-NF antibodies by flow cytometry using HEK293 cell lines stably expressing human NF155 or NF186. Four additional CIDP patients with anti-NF155 antibodies referred from other clinics were enrolled for clinical characterization. RESULTS: The positivity rate for anti-NF155 antibodies in CIDP patients was 18% (9/50), who all showed a predominance of IgG4 subclass. No other subjects were positive, except one GBS patient harboring IgG1 anti-NF155 antibodies. No anti-NF155 antibody carriers had anti-NF186 antibodies. Anti-NF155 antibody-positive CIDP patients had a significantly younger onset age, higher frequency of drop foot, gait disturbance, tremor and distal acquired demyelinating symmetric phenotype, greater cervical root diameter on magnetic resonance imaging neurography, higher cerebrospinal fluid protein levels, and longer distal and F-wave latencies than anti-NF155 antibody-negative patients. Marked symmetric hypertrophy of cervical and lumbosacral roots/plexuses was present in all anti-NF155 antibody-positive CIDP patients examined by neurography. Biopsied sural nerves from two patients with anti-NF155 antibodies demonstrated subperineurial edema and occasional paranodal demyelination, but no vasculitis, inflammatory cell infiltrates, or onion bulbs. Among anti-NF155 antibody-positive patients, treatment responders more frequently had daily oral corticosteroids and/or immunosuppressants in addition to intravenous immunoglobulins than nonresponders did. INTERPRETATION: Anti-NF155 antibodies occur in a subset of CIDP patients with distal-dominant involvement and symmetric nerve hypertrophy.

Intravoxel incoherent motion magnetic resonance imaging findings in the acute phase of MELAS: a case report.

OBJECTIVE: We report the clinical application of intravoxel incoherent motion (IVIM) magnetic resonance (MR) imaging to diagnose a case of mitochondrial myopathy, encephalopathy, lactic acidosis, and stroke-like episodes (MELAS) in the acute phase. RESULTS: On IVIM MR Images of this patient, higher perfusion (f) and diffusion (D) values in the left occipital and temporal lobes were found compared to the contralateral areas. CONCLUSION: These findings imply a breakdown of autoregulation with hyperperfusion and vasogenic edema during the acute phase of MELAS, as described in previous reports. IVIM imaging is a valuable, noninvasive tool that simultaneously quantifies perfusion and diffusion parameters.

Peripheral blood T cell dynamics predict relapse in multiple sclerosis patients on fingolimod.

BACKGROUND: Fingolimod efficiently reduces multiple sclerosis (MS) relapse by inhibiting lymphocyte egress from lymph nodes through down-modulation of sphingosine 1-phosphate (S1P) receptors. We aimed to clarify the alterations in peripheral blood T cell subsets associated with MS relapse on fingolimod. METHODS/PRINCIPAL FINDINGS: Blood samples successively collected from 23 relapsing-remitting MS patients before and during fingolimod therapy (0.5 mg/day) for 12 months and 18 healthy controls (HCs) were analysed for T cell subsets by flow cytometry. In MS patients, the percentages of central memory T (CCR7+CD45RO+) cells (TCM) and naïve T (CCR7+CD45RO-) cells decreased significantly, while those of effector memory T (CCR7-CD45RA-) and suppressor precursor T (CD28-) cells increased in both CD4+T and CD8+T cells from 2 weeks to 12 months during fingolimod therapy. The percentages of regulatory T (CD4+CD25highCD127low) cells in CD4+T cells and CCR7-CD45RA+T cells in CD8+T cells also increased significantly. Eight relapsed patients demonstrated greater percentages of CD4+TCM than 15 non-relapsed patients at 3 and 6 months (p=0.0051 and p=0.0088, respectively). The IL17-, IL9-, and IL4-producing CD4+T cell percentages were significantly higher at pre-treatment in MS patients compared with HCs (p<0.01 for all), while the IL17-producing CD4+T cell percentages tended to show a transient increase at 2 weeks of fingolimod therapy (pcorr=0.0834). CONCLUSIONS: The CD4+TCM percentages at 2 weeks to 12 months during fingolimod therapy are related to relapse.