Satoshi Yoshimura

Distinct genetic and infectious profiles in Japanese neuromyelitis optica patients according to anti-aquaporin 4 antibody status

Objective To clarify whether genetic and common infectious backgrounds are distinct, according to anti-aquaporin 4 (AQP4) antibody status in Japanese patients with neuromyelitis optica (NMO). Methods We analysed human leucocyte antigen (HLA)-DRB1 and HLA-DPB1 alleles, and IgG antibodies against Helicobacter pylori, Chlamydia pneumoniae, varicella zoster virus and Epstein–Barr virus nuclear antigen (EBNA) in 116 patients with NMO, including 39 patients with neuromyelitis optica spectrum disorder (NMOSD), 145 multiple sclerosis (MS) patients and 367 unrelated healthy controls. 77 NMO/NMOSD patients were seropositive for AQP4 antibody while 39 were seronegative. Results Compared with healthy controls, NMO/NMOSD patients showed a significantly lower frequency of DRB1*0901 and significantly higher frequencies of DRB1*1602 and DPB1*0501, which conferred susceptibility to anti-AQP4 antibody positive NMO/NMOSD, but not antibody negative NMO/NMOSD. DRB1*0901 was a common protective allele, irrespective of the presence or absence of anti-AQP4 antibody. Anti-H pylori and anti-C pneumoniae antibodies were more commonly detected in anti-AQP4 antibody positive NMO/NMOSD patients than healthy controls. Antibody negative NMO/NMOSD patients did not differ from healthy controls regarding the presence of these antibodies. The presence or absence of antibodies against varicella zoster virus and EBNA did not vary among the groups. The frequencies of antibodies against these four pathogens were not significantly different between MS patients and healthy controls. Conclusions Our results suggest that HLA-DRB1*1602 and DPB1*0501 alleles and H pylori and Chlamydia pneumonia infection are risk factors only for anti-AQP4 antibody positive NMO/NMOSD but not for anti-AQP4 antibody negative NMO/NMOSD.

Genetic and Infectious Profiles of Japanese Multiple Sclerosis Patients

Background Nationwide surveys conducted in Japan over the past thirty years have revealed a four-fold increase in the estimated number of multiple sclerosis (MS) patients, a decrease in the age at onset, and successive increases in patients with conventional MS, which shows an involvement of multiple sites in the central nervous system, including the cerebrum and cerebellum. We aimed to clarify whether genetic and infectious backgrounds correlate to distinct disease phenotypes of MS in Japanese patients. Methodology/Principal Findings We analyzed HLA-DRB1 and -DPB1 alleles, and IgG antibodies specific for Helicobacter pylori, Chlamydia pneumoniae, varicella zoster virus, and Epstein-Barr virus nuclear antigen (EBNA) in 145 MS patients and 367 healthy controls (HCs). Frequencies of DRB1*0405 and DPB1*0301 were significantly higher, and DRB1*0901 and DPB1*0401 significantly lower, in MS patients as compared with HCs. MS patients with DRB1*0405 had a significantly earlier age of onset and lower Progression Index than patients without this allele. The proportion and absolute number of patients with DRB1*0405 successively increased with advancing year of birth. In MS patients without DRB1*0405, the frequency of the DRB1*1501 allele was significantly higher, while the DRB1*0901 allele was significantly lower, compared with HCs. Furthermore, DRB1*0405-negative MS patients were significantly more likely to be positive for EBNA antibodies compared with HCs. Conclusions Our study suggests that MS patients harboring DRB1*0405, a genetic risk factor for MS in the Japanese population, have a younger age at onset and a relatively benign disease course, while DRB1*0405-negative MS patients have features similar to Western-type MS in terms of association with Epstein-Barr virus infection and DRB1*1501. The recent increase of MS in young Japanese people may be caused, in part, by an increase in DRB1*0405-positive MS patients.

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.

A case of hereditary diffuse leukoencephalopathy with axonal spheroids caused by a de novo mutation in CSF1R masquerading as primary progressive multiple sclerosis

We report a sporadic case of hereditary diffuse leukoencephalopathy with axonal spheroids (HDLS) confirmed by biopsy and colony-stimulating factor 1 receptor (CSF1R) sequencing. A 28-year-old woman developed progressive spastic gait and dysarthria. Brain T2/FLAIR-weighted magnetic resonance imaging showed bilateral high signal intensity lesions in the parietal deep white matter, which subsequently extended anteriorly. Biopsied brain specimens demonstrated demyelinated white matter tissue with axonal spheroids infiltrated with foamy macrophages, and CD8+ and CD4+ T cells. She had a heterozygous mutation, c.2381T>C (p.782 Ile>Thr), in CSF1R. This is the first genetically proven case of HDLS mimicking primary progressive multiple sclerosis.

Quantitative assays for anti-aquaporin-4 antibody with subclass analysis in neuromyelitis optica

Background: To clarify the clinical relevance of anti-aquaporin-4 (anti-AQP4) antibody titers and immunoglobulin (IgG) subclass. Methods: Using a bridging enzyme-linked immunosorbent assay (ELISA), a flow cytometric assay (FCMA) and an immunofluorescence assay (IFA) for anti-AQP4 antibodies, sera from 142 patients with multiple sclerosis (MS) as defined by the McDonald criteria (2005), 29 with neuromyelitis optica (NMO) who fulfilled the 1999 criteria, 19 with recurrent and/or longitudinally extensive myelitis (RM/LM), 86 with other non-inflammatory neurological diseases (OND) and 28 healthy controls (HC) were studied. Results: Anti-AQP4 antibody positivity rates by IFA, FCMA, and ELISA were 41.4%, 51.7% and 48.3%, respectively, in NMO (1999) patients, and 0% in the OND and HC groups. Twenty-six MS patients (18.3%) were positive for the antibody; 17 met the 2006 NMO criteria, including positivity for anti-AQP4 antibody, and five had longitudinally extensive myelitis (LM). Among the cases with anti-AQP4 antibody detected by FCMA, IgG1, 2, 3, and 4 anti-AQP4 antibodies were found in 97.8%, 37.0%, 6.5% and 6.5% respectively. There was no association of either antibody positivity or level of anti-AQP4 antibody IgG subclasses with clinical parameters after adjustment of p values for multiple comparisons. Conclusions: FCMA and bridging ELISA are useful for detecting and quantifying anti-AQP4 antibodies.

Genetic and infectious profiles influence cerebrospinal fluid IgG abnormality in Japanese multiple sclerosis patients.

Background Abnormal intrathecal synthesis of IgG, reflected by cerebrospinal fluid (CSF) oligoclonal IgG bands (OBs) and increased IgG index, is much less frequently observed in Japanese multiple sclerosis (MS) cohorts compared with Western cohorts. We aimed to clarify whether genetic and common infectious backgrounds influence CSF IgG abnormality in Japanese MS patients. Methodology We analyzed HLA-DRB1 alleles, and IgG antibodies against Chlamydia pneumoniae, Helicobacter pylori, Epstein-Barr virus nuclear antigen (EBNA), and varicella zoster virus (VZV) in 94 patients with MS and 367 unrelated healthy controls (HCs). We defined CSF IgG abnormality as the presence of CSF OBs and/or increased IgG index (>0.658). Principal Findings CSF IgG abnormality was found in 59 of 94 (62.8%) MS patients. CSF IgG abnormality-positive patients had a significantly higher frequency of brain MRI lesions meeting the Barkhof criteria compared with abnormality-negative patients. Compared with HCs, CSF IgG abnormality-positive MS patients showed a significantly higher frequency of DRB1*1501, whereas CSF IgG abnormality-negative patients had a significantly higher frequency of DRB1*0405. CSF IgG abnormality-positive MS patients had a significantly higher frequency of anti-C. pneumoniae IgG antibodies compared with CSF IgG abnormality-negative MS patients, although there was no difference in the frequency of anti-C. pneumoniae IgG antibodies between HCs and total MS patients. Compared with HCs, anti-H. pylori IgG antibodies were detected significantly less frequently in the total MS patients, especially in CSF IgG abnormality-negative MS patients. The frequencies of antibodies against EBNA and VZV did not differ significantly among the groups. Conclusions CSF IgG abnormality is associated with Western MS-like brain MRI features. DRB1*1501 and C. pneumoniae infection confer CSF IgG abnormality, while DRB1*0405 and H. pylori infection are positively and negatively associated with CSF IgG abnormality-negative MS, respectively, suggesting that genetic and environmental factors differentially contribute to MS susceptibility according to the CSF IgG abnormality status.

Interleukin-7 receptor alpha gene polymorphism influences multiple sclerosis risk in Asians

A recent genome-wide survey identified non–human leukocyte antigen ( HLA ) genes that are related to multiple sclerosis (MS). Among these, an association of a single nucleotide polymorphism (SNP), rs6897932, in the interleukin-7 receptor α gene ( IL-7RA ) with MS susceptibility has been widely replicated in Caucasians.1,–,3 The SNP located in the transmembrane domain of IL-7Rα is nonsynonymous and functional: the MS-susceptible CC allele increases levels of the soluble form of IL-7Rα via exon skipping, and decreases the expression of membrane-bound IL-7Rα, thereby causing decreased IL-7/IL-7R signaling.1,–,3 IL-7/IL-7R signaling induces thymic production of FOXP3+ regulatory T cells, which efficiently ameliorate experimental autoimmune encephalomyelitis,4 an animal model of MS. Thus, the rs6897932 polymorphism of the IL-7RA gene may confer MS susceptibility through decreased production of FOXP3+ regulatory T cells due to downregulated IL-7/IL-7R signaling. This polymorphism has never been reported in either MS or neuromyelitis optica (NMO) in Asians. Therefore, in the present cross-sectional study, we investigated the association of the IL-7RA SNP rs6897932 with non-NMO MS and NMO in the Japanese. ### Methods. All patients with NMO fulfilled the 2006 Wingerchuk5 criteria for NMO, while those with NMO spectrum disorders who did not completely meet the criteria were excluded. All non-NMO patients with MS satisfied …

Altered production of brain-derived neurotrophic factor by peripheral blood immune cells in multiple sclerosis

Background: Within multiple sclerosis lesions, brain-derived neurotrophic factor is detected in neurons and immunocytes. Objective: To clarify brain-derived neurotrophic factor production by peripheral blood immunocytes and its relationship with clinical parameters in multiple sclerosis. Methods: Serum brain-derived neurotrophic factor levels were measured by conventional enzyme-linked immunosorbent assay while brain-derived neurotrophic factor production by immunocytes was determined by an in situ enzyme-linked immunosorbent assay in 74 multiple sclerosis patients, 32 healthy controls, and 86 patients with other neurological diseases. The tyrosine kinase receptor TrkB expression level in peripheral blood mononuclear cells was measured by real-time polymerase chain reaction. Results: Multiple sclerosis patients showed significantly higher serum brain-derived neurotrophic factor levels than healthy controls and patients with other neurological diseases. Multiple sclerosis patients with high brain-derived neurotrophic factor levels were younger, and showed fewer relapse numbers than those with low brain-derived neurotrophic factor levels. Brain-derived neurotrophic factor production by T cells increased with age in healthy controls, but not in multiple sclerosis patients. Interferon beta induced a significant increase in serum brain-derived neurotrophic factor levels. Brain-derived neurotrophic factor production from T cells and TrkB expression levels in peripheral blood mononuclear cells were significantly enhanced in interferon beta-treated multiple sclerosis patients compared with untreated ones. Conclusions: A high brain-derived neurotrophic factor level is related to early mild disease in young multiple sclerosis patients. Interferon beta potentiates brain-derived neurotrophic factor production and brain-derived neurotrophic factor receptor expression in peripheral blood mononuclear cells, which may act beneficially.

Interleukin 2 receptor α chain gene polymorphisms and risks of multiple sclerosis and neuromyelitis optica in southern Japanese

BACKGROUND Interleukin 2 receptor α subunit (IL2RA) is a genetic risk for multiple sclerosis (MS) in Caucasians. However, the association between MS and IL2RA in Japanese idiopathic demyelinating diseases of the central nervous system has not been examined. OBJECTIVE To determine whether IL2RA gene polymorphisms confer risks of developing MS or neuromyelitis optica (NMO) in a Japanese population. METHODS DNA samples were obtained from 115 MS patients, 75 NMO/NMO spectrum disorder (NMOSD) patients, and 238 healthy controls. The single nucleotide polymorphisms (SNPs) rs2104286, rs12722489, and rs7090512 were genotyped by real-time PCR using TaqMan SNP genotyping assays. RESULTS No significant associations of the three IL2RA SNPs with the development of the diseases were observed. In MS patients only, the annualized relapse rates were significantly higher for the rs2104286-TT genotype than for the non-TT (CT+CC) genotype and for the rs12722489-CC genotype than for the non-CC genotype in females (p = 0.0138 for both), but not in males. CONCLUSIONS Although the possibility that IL2RA is a risk factor for MS development was not confirmed in this Japanese population, IL2RA gene polymorphisms were able to modify the disease activity in female MS patients, but had no influence on either susceptibility or disease phenotype in NMO/NMOSD patients.

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.