IL-35-producing B cells are critical regulators of immunity during autoimmune and infectious diseases.

B lymphocytes have critical roles as positive and negative regulators of immunity. Their inhibitory function has been associated primarily with interleukin 10 (IL-10) because B-cell-derived IL-10 can protect against autoimmune disease and increase susceptibility to pathogens. Here we identify IL-35-producing B cells as key players in the negative regulation of immunity. Mice in which only B cells did not express IL-35 lost their ability to recover from the T-cell-mediated demyelinating autoimmune disease experimental autoimmune encephalomyelitis (EAE). In contrast, these mice displayed a markedly improved resistance to infection with the intracellular bacterial pathogen Salmonella enterica serovar Typhimurium as shown by their superior containment of the bacterial growth and their prolonged survival after primary infection, and upon secondary challenge, compared to control mice. The increased immunity found in mice lacking IL-35 production by B cells was associated with a higher activation of macrophages and inflammatory T cells, as well as an increased function of B cells as antigen-presenting cells (APCs). During Salmonella infection, IL-35- and IL-10-producing B cells corresponded to two largely distinct sets of surface-IgM(+)CD138(hi)TACI(+)CXCR4(+)CD1d(int)Tim1(int) plasma cells expressing the transcription factor Blimp1 (also known as Prdm1). During EAE, CD138(+) plasma cells were also the main source of B-cell-derived IL-35 and IL-10. Collectively, our data show the importance of IL-35-producing B cells in regulation of immunity and highlight IL-35 production by B cells as a potential therapeutic target for autoimmune and infectious diseases. This study reveals the central role of activated B cells, particularly plasma cells, and their production of cytokines in the regulation of immune responses in health and disease.

Fingolimod induces BAFF and expands circulating transitional B cells without activating memory B cells and plasma cells in multiple sclerosis.

Patients with multiple sclerosis (MS) who are treated with fingolimod have an increased proportion of transitional B cells in the circulation, but the underlying mechanism is not known. We hypothesized that B cell-activating factor of the tumor necrosis factor family (BAFF) is involved in the process. Compared with healthy controls and untreated MS patients, fingolimod-treated MS patients had significantly higher serum concentrations of BAFF, which positively correlated with the proportions and the absolute numbers of transitional B cells in blood. Despite the elevated concentrations of BAFF in fingolimod-treated MS patients, serum levels of soluble transmembrane activator and calcium-modulating cyclophilin ligand interactor, and B cell maturation antigen were not elevated. Our results show that fingolimod induces BAFF in the circulation and expands transitional B cells, but does not activate memory B cells or plasma cells in MS, which is favorable for the treatment of this disease.

Latitude and HLA-DRB1*04:05 independently influence disease severity in Japanese multiple sclerosis: a cross-sectional study.

BACKGROUND: Higher latitude and human leukocyte antigen (HLA)-DRB1*04:05 increase susceptibility to multiple sclerosis (MS) in the Japanese population, but their effects on disease severity are unknown. We aimed to clarify the effects of latitude and the HLA-DRB1 and HLA-DPB1 genes on disease severity in Japanese patients with MS. METHODS: We enrolled 247 MS patients and 159 healthy controls (HCs) from the northernmost main island of Japan, Hokkaido Island (42-45° north), and 187 MS patients and 235 HCs from the southern half (33-35° north) of the Japanese archipelago (33-45° north). We genotyped HLA-DRB1 and HLA-DPB1 alleles, compared demographic features, and analyzed factors contributing to differences in clinical and laboratory findings between MS patients from southern and northern Japan. The Multiple Sclerosis Severity Score (MSSS), which adjusts the Kurtzke's Expanded Disability Status Scale score according to disease duration, was used to estimate disease severity. RESULTS: The HLA-DRB1*04:05 and DRB1*15:01 alleles conferred susceptibility to MS in our Japanese population (p (corr) = 0.0004 and p (corr) = 0.0019, respectively). Southern patients had higher MSSS scores than northern patients (p = 0.003). Northern patients had higher frequencies of brain lesions meeting the Barkhof criteria (Barkhof brain lesions) and cerebrospinal fluid (CSF) IgG abnormalities than southern patients (p = 0.0012 and p < 0.0001, respectively). DRB1*04:05-positive MS patients had lower MSSS scores and lower frequencies of Barkhof brain lesions and CSF IgG abnormalities than DRB1*04:05-negative MS patients (p = 0.0415, p = 0.0026, and p < 0.0001, respectively). Multivariate analyses revealed that latitude and DRB1*04:05 were independently associated with the lowest quartile of MSSS and that latitude was positively associated with Barkhof brain lesions and CSF IgG abnormalities. DRB1*04:05 was negatively associated with these parameters. MSSS was decreased by 0.57 per DRB1*04:05 allele (p = 0.0198). CONCLUSIONS: Living at a higher latitude and carrying the DRB1*04:05 allele independently lessens MS symptom severity as defined by MSSS. However, these factors influence the frequency of Barkhof brain lesions and CSF IgG abnormalities in opposite ways; higher latitude increases the frequency of Barkhof brain lesions and CSF IgG abnormalities, whereas DRB1*04:05 decreases them.

Latitude and HLA-DRB1 alleles independently affect the emergence of cerebrospinal fluid IgG abnormality in multiple sclerosis.

BACKGROUND: It is unclear whether the prevalence of oligoclonal IgG bands (OCBs) in multiple sclerosis (MS) is different between northern and southern regions of Asia. OBJECTIVE: This study aimed to compare the prevalence of OCBs and positive cerebrospinal fluid (CSF) findings between northern and southern regions of Japan and to investigate the association of these CSF findings with HLA-DRB1 alleles. METHODS: The study included 180 MS patients from Hokkaido (northern Japan) and 184 patients from Kyushu (southern Japan). The IgG index was defined as increased if it was >0.658. Presence of CSF OCBs and/or increased IgG index was defined as positive CSF findings. RESULTS: Positive CSF findings and OCB positivity were significantly higher in MS patients from Hokkaido than in those from Kyushu (p < 0.0001 for both). Logistic regression analysis revealed that after adjusting for covariates that can be related to abnormal CSF IgG production, the geographic region (Hokkaido) showed odds ratios (ORs) of 4.08 and 2.57, whereas the HLA-DRB1*04:05 allele showed ORs of 0.36 and 0.30 for positive CSF findings and OCB positivity, respectively. CONCLUSIONS: The results indicate that latitude and HLA-DRB1 alleles independently affect the emergence of CSF IgG abnormalities in Japanese patients with MS.

Genetic polymorphisms related to vitamin D and the therapeutic potential of vitamin D in multiple sclerosis.

Vitamin D receptors (VDRs), which are responsible for most vitamin D functions, are expressed on various immune cells. Vitamin D is considered to be a potent immunomodulator. A variety of cells in the central nervous system (CNS) also express VDRs; thus, vitamin D may play a role in the regulation of neurodegeneration and repair processes within the CNS. Considered together with epidemiological studies, low vitamin D status is reckoned to be one of the risk factors for multiple sclerosis (MS). Further, vitamin D is considered to be a possible treatment for MS. However, previous clinical trials with small cohorts have not demonstrated significant effects of vitamin D in MS. Current ongoing clinical trials with large cohorts could provide answers with respect to the clinical effects of vitamin D in MS. However, genetic studies have suggested that genes associated with vitamin D, including VDRs, are susceptible genes for MS. Vitamin D needs to be considered from the perspective of the interaction between vitamin-D-related genetic factors and environmental factors affecting vitamin D levels.

Suppressed pro-inflammatory properties of circulating B cells in patients with multiple sclerosis treated with fingolimod, based on altered proportions of B-cell subpopulations.

The chief therapeutic mechanism of fingolimod in multiple sclerosis (MS) is considered to be sequestration of pathogenic lymphocytes into secondary lymphoid tissues. B cells have recently been recognized as important immune regulators in MS. In this study, the effects of fingolimod on B cells in MS patients were analyzed. MS patients treated with fingolimod (MS-F) had a significantly lower number of B cells in the circulation. The remaining B cells in the blood of MS-F had a reduced proportion of memory B cells and an increased proportion of naïve B cells, expressed lower levels of the costimulatory molecule CD80, and produced less tumor necrosis factor-α and more interleukin-10. These observations in MS-F were based on an increased proportion of the transitional B-cell subpopulation within the naïve B-cell compartment. The observed findings in B cells of MS-F might be related to the therapeutic effect of this drug in MS.

Apathy/depression, but not subjective fatigue, is related with cognitive dysfunction in patients with multiple sclerosis.

BACKGROUND: Cognitive impairment could affect quality of life for patients with multiple sclerosis (MS), and cognitive function may be correlated with several factors such as depression and fatigue. This study aimed to evaluate cognitive function in Japanese patients with MS and the association between cognitive function and apathy, fatigue, and depression. METHODS: The Brief Repeatable Battery of Neuropsychological tests (BRB-N) was performed in 184 Japanese patients with MS and 163 healthy controls matched for age, gender, and education. The Apathy Scale (AS), Fatigue Questionnaire (FQ), and Beck Depression Inventory Second Edition (BDI-II) were used to evaluate apathy, fatigue, and depression, respectively. Student's t-test was used to compare MS patients and healthy controls. Correlations between two factors were assessed using the Pearson correlation test, and multiple regression analysis was used to evaluate how much each factor affected the BRB-N score. RESULTS: In all BRB-N tests, patients with MS scored significantly lower than controls, and the effect size of symbol digit modalities test was the highest among the 9 tests of the BRB-N. Patients with MS had higher AS (p < 0.001), FQ (p < 0.0001), and BDI-II (p < 0.0001) scores than controls. In patients with MS, scores on most of the BRB-N tests correlated with scores on the AS and BDI-II; however, there was little correlation between scores on the BRB-N tests and those on the FQ. CONCLUSIONS: Cognitive function was impaired, particularly information-processing speed, and decreased cognitive function was correlated with apathy and depression in Japanese patients with MS. Despite the association between cognitive variables and depression/apathy, cognitive function was impaired beyond the effect of depression and apathy. However, subjective fatigue is not related with cognitive impairment. Taken together, this suggests that different therapeutic approaches are needed to improve subjective fatigue and cognition, and thereby quality of life, in patients with MS.

Interleukin 6 signaling promotes anti-aquaporin 4 autoantibody production from plasmablasts in neuromyelitis optica.

Neuromyelitis optica (NMO) is an inflammatory disease affecting the optic nerve and spinal cord, in which autoantibodies against aquaporin 4 (AQP4) water channel protein probably play a pathogenic role. Here we show that a B-cell subpopulation, exhibiting the CD19(int)CD27(high)CD38(high)CD180(-) phenotype, is selectively increased in the peripheral blood of NMO patients and that anti-AQP4 antibodies (AQP4-Abs) are mainly produced by these cells in the blood of these patients. These B cells showed the morphological as well as the phenotypical characteristics of plasmablasts (PB) and were further expanded during NMO relapse. We also demonstrate that interleukin 6 (IL-6), shown to be increased in NMO, enhanced the survival of PB as well as their AQP4-Ab secretion, whereas the blockade of IL-6 receptor (IL-6R) signaling by anti-IL-6R antibody reduced the survival of PB in vitro. These results indicate that the IL-6-dependent B-cell subpopulation is involved in the pathogenesis of NMO, thereby providing a therapeutic strategy for targeting IL-6R signaling.

[Vitamin D and latitude as environmental factors in multiple sclerosis].

Multiple sclerosis (MS) shows a multifold increase in prevalence with an increase in latitudes, both north and south of the equator. One of the potential factors related to the difference of the prevalence is vitamin D, because the strength of ambient ultraviolet light, which is essential for vitamin D production, decreases with increasing latitude. It is known that vitamin D has immunomodulatory functions and suppresses an animal model of MS. It is also considered that vitamin D-related genes are critical susceptible genes for MS. An approach from environmental and genetic aspects is needed to investigate the association between vitamin D and MS.

[B-cell Therapy for Multiple Sclerosis].

B-cell therapy using anti-CD20 antibodies significantly suppresses relapse and is therefore an important treatment option for multiple sclerosis (MS). Based on the production of inflammatory cytokines and enhanced antigen-presenting capacity, B cells trigger MS relapses via activation of pathogenic T cells. Suppression of these abnormal actions of B cells is the primary mechanism underlying relapse prevention using B-cell therapies. Treatments that target B cells are also expected to suppress chronic progression of MS through modulation of B-cell activity within the central nervous system. B-cell therapies based on novel approaches are expected to improve the regulation of acute and chronic MS pathology.

Interleukin-6 Immunology in Macrophage Activation Syndrome Related to Neuroimmunological Diseases.

Macrophage activation syndrome (MAS) involves an excessive amount of acute inflammatory responses to inflammatory cytokines, particularly interleukin-6 (IL-6). IL-6 is also strongly associated with the pathophysiology of certain neuroimmunological diseases. However, there have so far been few reports of MAS being accompanied by neuroimmunological diseases. We herein report two cases of MAS comorbid with myasthenia gravis or neuromyelitis optica spectrum disorders, IL-6 related neuroimmunological diseases. Standard immunosuppressive therapies could not stabilize the symptoms in our cases until antibodies against the IL-6 receptor were administered. This finding suggests that it is important to consider the underlying pathophysiology of MAS in relation to these neuroimmunological diseases when treating affected patients.

Japanese translation and validation of the 12-item Multiple Sclerosis Walking Scale version 2.

BACKGROUND: Disability in ambulation has a critical impact on activities of daily living in patients with multiple sclerosis (MS). The 12-item Multiple Sclerosis Walking Scale (MSWS-12) is a self-reported instrument developed to assess the impact of MS on walking. The scale's 12 items assess various aspects of walking-related tasks during the past 2 weeks. MSWS-12 has been used in multiple clinical studies and translated into several languages. In the present study, we translated the MSWS-12 into Japanese and evaluated its psychometric properties in a cross-sectional study. METHODS: The original English MSWS-12 version 2 (v2) was translated into Japanese through a standard procedure. Sixty consecutive Japanese MS patients completed the newly prepared Japanese MSWS-12v2 questionnaire and repeated the test 14 days later. Physical disability was assessed by the Expanded Disability Status Scale (EDSS), Timed 25-foot Walk (T25FW), and 9-hole Peg Test (9HPT). Cognitive performance was evaluated using the Processing Speed Test (PST). Fatigue and health-related quality of life were assessed using the Japanese versions of the Fatigue Severity Scale (FSS) and the Functional Assessment of MS (FAMS). RESULTS: The mean age of the patients was 42.5 years, with median disease duration of 10 years, and median EDSS of 2.0 (range 0, 6.5). Forty-seven patients (78.3 %) had relapsing-remitting, 9 (15.0 %) had secondary-progressive, and 4 (6.7 %) had primary-progressive phenotypes. The median score of the MSWS-12v2 was 5.95 (interquartile range 0, 50.6). Twenty-seven patients (45 %) scored the lowest possible score (0 points), while one (1.7 %) scored the highest possible score (100 points). Cronbach's alpha was 0.98 (95 % confidence interval [CI] 0.97, 0.98), and the test-retest intraclass correlation was 0.95 (95%CI 0.94, 0.96). MSWS-12v2 score was strongly correlated with EDSS (Spearman's ρ = 0.73 [95%CI 0.58, 0.83]), T25FW (ρ = 0.70 [95%CI 0.55, 0.81]), and total FAMS score (ρ = -0.80 [95%CI -0.88, -0.69]), and moderately correlated with 9HPT (ρ = 0.65 [95%CI 0.47, 0.77] for the dominant hand; ρ = 0.62 [95%CI 0.43, 0.75] for the non-dominant hand), PST (ρ = -0.65 [95%CI -0.78, -0.47]), and FSS (ρ = 0.68 [95%CI 0.52, 0.80]). Among the subcomponents of FAMS, the mobility subcomponent showed the most robust correlation with MSWS-12v2 score (ρ = -0.91 [95%CI -0.94, -0.81]). In patients with minimal or no objective disability (EDSS < 3.0, n = 40), only the mobility subcomponent of FAMS was strongly correlated with MSWS-12v2 score (ρ = -0.76 [95% CI -0.87, -0.58]). In contrast, correlations of MSWS-12v2 score with EDSS and T25FW were weak in this subgroup (ρ = 0.28 [95%CI -0.03, 0.55] for EDSS; ρ = 0.25 [95%CI -0.06, 0.52] for T25FW). Response patterns for the single items showed that 32.5 % of the patients with EDSS below 3.0 reported having problems with balance, followed by climbing stairs and standing while doing things (both 25 %). CONCLUSION: The Japanese version of the MSWS-12v2 developed in this study is reliable, valid, and helpful for screening walking disability in Japanese MS patients, including those with minimal objective disability.

Safety and Effectiveness of Satralizumab in Japanese Patients with Neuromyelitis Optica Spectrum Disorder: A 6-month Interim Analysis of Post-marketing Surveillance.

INTRODUCTION: Satralizumab, an anti-interleukin-6 receptor antibody, is approved in Japan for relapse prevention in neuromyelitis optica spectrum disorder (NMOSD) and is undergoing post-marketing surveillance (PMS) of clinical use. We aimed to describe the real-world safety and effectiveness of satralizumab in Japanese patients with NMOSD. METHODS: This is an ongoing PMS (planned completion: February 2027). This 6-month interim analysis assessed the safety and effectiveness of satralizumab in Japanese patients with NMOSD using data collected from August 2020 to July 2021. RESULTS: Among 570 patients who participated, 523 (91.75%) were female and the mean ± standard deviation (SD) age was 52.4 ± 14.1 years. At baseline, NMOSD expanded disability status scale mean ± SD was 4.19 ± 2.19; 490 (85.96%) patients used glucocorticoids and 277 (48.59%) patients used immunosuppressants concomitantly. Of 570 satralizumab-treated patients, 85 (14.91%) had discontinued satralizumab treatment at 6 months. For the overall adverse drug reactions (ADRs), 76.22 (66.07-87.48) events/100 person-years occurred in 118 (20.70%) patients, and infections occurred in 28 (4.91%) patients. Serious infections occurred in 18 (3.15%) patients, with an event rate of 9.05 (5.80-13.47) events/100 person-years. Of the 24 events of serious infections, respiratory tract infections (29.17%; 7) and urinary tract infections (25.00%; 6) were the most common serious infection events. One fatal ADR (septic shock) suspected to be related to satralizumab was reported. The mean ± SD glucocorticoid dose reduced from 12.28 ± 10.17 mg/day at the index date to 8.11 ± 7.30 mg/day at 6 months. The Kaplan-Meier cumulative relapse-free rate (95% confidence interval) was 94.59% (92.25-96.23) at 6 months. CONCLUSION: In this study, satralizumab was found to be safe, well tolerated, and effective in patients with NMOSD in routine clinical practice. The results are consistent with those of previous clinical trials. The safety and effectiveness of satralizumab in Japanese patients with NMOSD will be analyzed over the 6-year surveillance period. TRIAL REGISTRATION: UMIN Clinical Trials Registry, UMIN000041047.

Characterization of Japanese multiple sclerosis patients with progression independent of relapse activity: A 2-year multicenter cohort study.

Progression independent of relapse activity (PIRA) is prevalent among Caucasian patients with relapsing and remitting multiple sclerosis (RRMS). However, there is limited knowledge regarding the characteristics of PIRA in Asian patients with RRMS. Therefore, we retrospectively analyzed the clinical and radiological progression of 95 Japanese patients with RRMS during a 2-year observation period. PIRA was observed in three patients who were characterized by young age, large T2 lesion volume, and great reduction in brain volume. Despite having highly active disease, fewer patients with PIRA (33.3%) were treated with high-efficacy drugs compared with those without disease activity (60.7%).

Clinical practice guidelines for multiple sclerosis, neuromyelitis optica spectrum disorder, and myelin oligodendrocyte glycoprotein antibody-associated disease 2023 in Japan.

BACKGROUND: The previous Japanese clinical practice guidelines for multiple sclerosis (MS) and neuromyelitis optica spectrum disorder (NMOSD) were published in 2017. Recently, for the first time in 6 years, the MS and NMOSD guideline development committee revised the Japanese guidelines for MS, NMOSD, and myelin oligodendrocyte glycoprotein antibody-associated disease (MOGAD). METHODS: The committee utilized the Grading of Recommendations Assessment, Development, and Evaluation system based on the "Minds Handbook for Clinical Practice Guideline Development 2020 Ver. 3.0″ with a focus on clinical questions (CQs). The committee also discussed clinical issues other than CQs, categorizing them as a question-and-answer (Q&A) section, including "issues on which experts' opinions agree to a certain extent" and "issues that are important but not included in the CQ". RESULTS: The committee identified 3, 1, and 1 key CQs related to MS, NMOSD, and MOGAD, respectively, and presented recommendations. A Q&A session regarding disease-modifying therapies and relapse prevention therapies for MS, NMOSD, and MOGAD was conducted. The revised guidelines were published in September 2023. CONCLUSIONS: The Japanese guidelines for clinical practice on MS, NMOSD, and MOGAD were updated. Treatment strategies for MS, NMOSD, and MOGAD are changing, and these updated guidelines may assist with treatment decisions for these diseases in clinical practice.

Mucosal-associated invariant T cells promote inflammation and exacerbate disease in murine models of arthritis.

OBJECTIVE: The function of mucosal-associated invariant T (MAIT) cells remains largely unknown. We previously reported an immunoregulatory role of MAIT cells in an animal model of multiple sclerosis. The aim of this study was to use animal models to determine whether MAIT cells are involved in the pathogenesis of arthritis. METHODS: MR1-/- and MR1+/+ DBA/1J mice were immunized with bovine type II collagen (CII) in complete Freund's adjuvant to trigger collagen-induced arthritis (CIA). To assess CII-specific T cell recall responses, lymph node cells from mice with CIA were challenged with CII ex vivo, and cytokine production and proliferation were evaluated. Serum levels of CII-specific antibodies were measured by enzyme-linked immunosorbent assay. Collagen antibody-induced arthritis (CAIA) was induced in MR1-/- and MR1+/+ C57BL/6 mice by injection of anti-CII antibodies followed by injection of lipopolysaccharide. To demonstrate the involvement of MAIT cells in arthritis, we induced CAIA in MR1-/- C57BL/6 mice that had been reconstituted with adoptively transferred MAIT cells. MAIT cell activation in response to cytokine stimulation was investigated. RESULTS: The severity of CIA was reduced in MR1-/- DBA/1J mice. However, T and B cell responses to CII were comparable in MR1-/- and MR1+/+ DBA/1J mice. MR1-/- C57BL/6 mice were less susceptible to CAIA, and reconstitution with MAIT cells induced severe arthritis in MR1-/- C57BL/6 mice, demonstrating an effector role of MAIT cells in arthritis. MAIT cells became activated upon stimulation with interleukin-23 (IL-23) or IL-1ß in the absence of T cell receptor stimuli. CONCLUSION: These results indicate that MAIT cells exacerbate arthritis by enhancing the inflammation.

[Thymoma-associated generalized myasthenia gravis complicated with anti-VGKC complex antibody-associated limbic encephalitis: a case report].

We present a case of a 54-year-old woman. She was attending our department for thymoma-associated generalized myasthenia gravis. While she was treated with intravenous immunoglobulins for the exacerbation of myasthenic symptoms, she suddenly lost her consciousness for the first time and continued to have mild disorientation along with anterograde and retrograde amnesia afterwards. The symptoms improved after steroid pulse therapy. After searching for autoantibodies, she was diagnosed with anti-VGKC complex antibody-associated limbic encephalitis. As one-third of cases are complicated by thymoma, anti-VGKC complex antibody-positive limbic encephalitis has the aspect of a paraneoplastic neurological syndrome. In this case, masses suspected to be a recurrence of thymoma were found. In cases of thymoma, involvement of anti-VGKC complex antibodies should be considered when central nervous system symptoms appear, and when anti-VGKC complex antibodies are positive, recurrence or exacerbation of thymoma should be considered.

Smoking and younger age at onset in anti-acetylcholine receptor antibody-positive myasthenia gravis.

Smoking is a known risk factor for the development and progression of several autoimmune diseases. Previous studies have pointed out the association of smoking with the development and worsening of symptoms in myasthenia gravis (MG), but further investigation is necessary to confirm this association. Smoking history was investigated in a cross-sectional study of 139 patients with anti-acetylcholine receptor antibody-positive MG, and the association of smoking history with the age at the onset of MG was analyzed. Patients who had been smoking at the onset of MG were significantly younger compared with those who had never smoked or had quit before the onset of MG. A linear regression analysis adjusting for sex and the presence/absence of thymoma showed a significant association between smoking at onset and younger age at onset (regression coefficient -9.05; 95% confidence interval, -17.6, -0.51; p = 0.039). Among patients with smoking exposure within 10 years prior to or at the onset of MG, women were significantly younger at the onset of MG compared with men. Our results suggest that smoking is an independent risk factor for the earlier development of anti-acetylcholine receptor antibody-positive MG and further support the putative link between smoking and MG.

Processing speed test: Results from a Japanese normative sample of healthy participants compared with a US normative sample.

BACKGROUND: The Processing Speed Test (PST), a validated iPad®-based cognitive screening test for MS, has been applied to the cognitive assessment of Japanese MS patients using US normative data. METHODS: To develop PST normative data from Japanese healthy volunteers and compare the PST score distribution between Japanese and US healthy volunteers, 254 healthy Japanese-speaking volunteers were enrolled and stratified by age (20-65 years). Potential participants with a Mini-Mental State Examination score < 27 were excluded. PST raw scores (total correct) were from the Japan cohort and compared with age-restricted US normative data and propensity score-matched data created by matching sex, age, and educational level from a published study of 428 healthy participants. PST score distributions and standardized z-scores were compared using t-test and Kolmogorov-Smirnov test statistics. RESULTS: The mean age of the Japan cohort was 44.1 years. The PST scores of Japanese volunteers were significantly different from those of the age-restricted (mean ± SD 61.8 ± 10.1 vs 53.7 ± 10.8; p < 0.001) and the propensity score-matched US cohort (62.1 ± 10.1 vs 53.3 ± 10.6; p < 0.001). CONCLUSION: Regression analyses centered on US normative data could underestimate disease severity in Japanese MS patients, suggesting that separate normative data should be considered for each population sample.

Health-related quality of life in Japanese patients with multiple sclerosis.

OBJECTIVES: Neurological disabilities, especially physical issues, can adversely affect the daily lives of people with multiple sclerosis (MS) and negatively impact their health-related quality of life (HRQOL). On the other hand, physical and psychiatric symptoms are variable in people with MS, and QOL can be influenced by cultural and educational background. This study aimed to evaluate the association of HRQOL with disabilities, fatigue, and depression in Japanese subjects with MS. METHODS: Evaluation of HRQOL, fatigue, and depression was performed in 184 Japanese individuals with MS, using the Functional Assessment of MS (FAMS), Fatigue Severity Scale (FSS), and Beck Depression Inventory-Second Edition (BDI-II), respectively. RESULTS: Multiple linear regression analysis demonstrated negative correlations of the Expanded Disability Status Scale (EDSS) with scores on the FAMS subscales of mobility, symptoms, thinking and fatigue, total FAMS, and additional concerns. The FSS score had negative correlations with mobility, symptoms, emotional well-being, thinking and fatigue, total FAMS, and additional concerns. There were negative correlations between BDI-II scores and all items of FAMS. CONCLUSIONS: HRQOL had relatively close correlations with disabilities and fatigue, and depression had an especially close relationship with HRQOL.