Comparisons of the phenotype frequencies of the <i>HLA-DRB1</i> alleles.

<p>*^aCompared with HCs, p^corr = 0.0196, OR  = 2.217, 95% CI  = 1.389–3.539.</p><p>*^bCompared with HCs, p^corr = 0.0056, OR  = 3.660, 95% CI  = 1.802–7.431.</p><p>*^cCompared with HCs, p^corr = 0.0084, OR  = 0.279, 95% CI  = 0.135–0.575.</p><p>*^dCompared with HCs, p^corr = 0.0392, OR  = 2.624, 95% CI 1.432–4.809.</p><p>p^uncorr was corrected by multiplying the value by 28 to calculate p^corr.</p><p>CI, confidence interval; CSF, cerebrospinal fluid; HCs, healthy controls; MS, multiple sclerosis; OR, odds ratio; p^corr, corrected p value.</p

Comparisons of the frequencies of antibodies against common infectious agents.

<p>*p = 0.0119, compared with IgG abnormality (−) MS patients.</p><p>**p = 0.0451, compared with HCs.</p><p>***p = 0.0474, compared with HCs.</p><p>*^,**^,***Significant difference between the linked values (p<0.05).</p><p>The age of the patients during examination did not differ significantly among HCs and MS patients, regardless of the presence or absence of IgG abnormality (mean ± SD in years: 37.21±12.54 for MS; 36.19±11.36 for IgG abnormality-positive MS; 39.00±14.39 for IgG abnormality-negative MS; and 38.93±12.11 for HCs).</p><p>CSF, cerebrospinal fluid; EBV, Epstein-Barr virus; HCs, healthy controls; MS, multiple sclerosis; p^corr, corrected p value; VZV, varicella zoster virus.</p

Proportions of patients with CSF IgG abnormality by year of birth.

<p>Among the MS patients, the proportion of patients with CSF IgG abnormality did not change significantly with advancing year of birth. CSF, cerebrospinal fluid; MS, multiple sclerosis.</p

Comparisons of the demographic features of MS patients according to the CSF IgG abnormality status.

a<p>Values represent the mean ± SD.</p>b<p>Brain MRI lesions meeting the Barkhof criteria <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0095367#pone.0095367-Barkhof1" target="_blank">[34]</a>.</p>c<p>Opticospinal form of MS with short spinal cord lesions extending less than three vertebral segments.</p><p>CSF, cerebrospinal fluid; EDSS, Kurtzke's Expanded Disability Status Scale; MS, multiple sclerosis.</p

Proportions of patients with <i>Helicobacter pylori</i> infection by year of birth.

<p>Among the MS patients, the proportion of patients with <i>H. pylori</i> decreased markedly in those born after 1965. MS, multiple sclerosis.</p

Genetic and Infectious Profiles of Japanese Multiple Sclerosis Patients

<div><h3>Background</h3><p>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.</p> <h3>Methodology/Principal Findings</h3><p>We analyzed <em>HLA-DRB1</em> and <em>-DPB1</em> alleles, and IgG antibodies specific for <em>Helicobacter pylori</em>, <em>Chlamydia pneumoniae</em>, varicella zoster virus, and Epstein-Barr virus nuclear antigen (EBNA) in 145 MS patients and 367 healthy controls (HCs). Frequencies of <em>DRB1*0405</em> and <em>DPB1*0301</em> were significantly higher, and <em>DRB1*0901</em> and <em>DPB1*0401</em> significantly lower, in MS patients as compared with HCs. MS patients with <em>DRB1*0405</em> had a significantly earlier age of onset and lower Progression Index than patients without this allele. The proportion and absolute number of patients with <em>DRB1*0405</em> successively increased with advancing year of birth. In MS patients without <em>DRB1*0405</em>, the frequency of the <em>DRB1*1501</em> allele was significantly higher, while the <em>DRB1*0901</em> allele was significantly lower, compared with HCs. Furthermore, <em>DRB1*0405</em>-negative MS patients were significantly more likely to be positive for EBNA antibodies compared with HCs.</p> <h3>Conclusions</h3><p>Our study suggests that MS patients harboring <em>DRB1*0405</em>, a genetic risk factor for MS in the Japanese population, have a younger age at onset and a relatively benign disease course, while <em>DRB1*0405</em>-negative MS patients have features similar to Western-type MS in terms of association with Epstein-Barr virus infection and <em>DRB1*1501</em>. The recent increase of MS in young Japanese people may be caused, in part, by an increase in <em>DRB1*0405</em>-positive MS patients.</p> </div

Frequencies of <i>HLA-DRB1</i> alleles among MS patients and healthy controls.

<p>p^uncorr was corrected by multiplying the value by 18 to calculate p^corr.</p><p>X^a includes all observed alleles at the <i>HLA-DRB1</i> locus with frequencies of less than 1% in subjects; <i>DRB1*0301, DRB1*0401, DRB1*0404, DRB1*0407, DRB1*0410, DRB1*0701, DRB1*1001, DRB1*1106, DRB1*1301, DRB1*1601</i> and <i>DRB1*1602</i>.</p><p>CI, confidence interval; HCs, healthy controls; MS, multiple sclerosis; NA, not applicable; OR, odds ratio; p^corr, corrected p value.</p

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<p>We recently reported that deletion-type copy number variations of the T cell receptor (TCR) γ, α, and δ genes greatly enhanced susceptibility to multiple sclerosis (MS). However, the effect of abnormal TCR γδ gene rearrangement on MS pathogenesis remains unknown. In the present study, we aimed to clarify γδ TCR repertoire alterations and their relationship to clinical and immunological parameters in MS patients by comprehensive flow cytometric immunophenotyping. Peripheral blood mononuclear cells obtained from 30 untreated MS patients in remission and 23 age- and sex-matched healthy controls (HCs) were stained for surface markers and intracellular cytokines after stimulation with phorbol 12-myristate 13-acetate and ionomycin, and analyzed by flow cytometry. MS patients showed significantly decreased percentages of Vδ2⁺ and Vδ2⁺Vγ9⁺ cells in γδ T cells (p^corr = 0.0297 and p^corr = 0.0288, respectively) and elevated Vδ1/Vδ2 ratios compared with HCs (p = 0.0033). The percentages of interferon (IFN)-γ⁺Vδ2⁺ and interleukin (IL)-17A⁺IFN-γ⁺Vδ2⁺ cells in γδ T cells, as well as IFN-γ⁺ cells in Vδ2⁺ γδ T cells, were significantly lower in MS patients than in HCs (p^corr < 0.0009, p^corr = 0.0135, and p^corr = 0.0054, respectively). The percentages of Vδ2⁺ and Vδ2⁺Vγ9⁺ cells in γδ T cells were negatively correlated with both the Expanded Disability Status Scale score (r = −0.5006, p = 0.0048; and r = −0.5040, p = 0.0045, respectively) and Multiple Sclerosis Severity Score (r = –0.4682, p = 0.0091; and r = –0.4706, p = 0.0087, respectively), but not with age at disease onset, disease duration, or annualized relapse rate. In HCs, the percentages of Vδ2⁺ and Vδ2⁺Vγ9⁺ cells of total CD3⁺ T cells had strong positive correlations with the percentage of CD25⁺CD127^low/− cells in CD4⁺ T cells (r = 0.7826, p < 0.0001; and r = 0.7848, p < 0.0001, respectively), whereas such correlations were totally absent in MS patients. These findings suggest that decreased Vδ2⁺Vγ9⁺ γδ T cells are associated with disability in MS. Therefore, the Vδ1/Vδ2 ratio might be a candidate biomarker for predicting disease severity in MS.</p

Proportion of <i>HLA-DRB1*0405</i>-positive and -negative MS patients by year of birth.

<p>Among MS patients, the proportion and absolute number of patients with <i>DRB1*0405</i> successively increased with advancing year of birth. MS, multiple sclerosis.</p

Comparison of demographic features and clinical characteristic of MS patients according to the presence or absence of the <i>HLA-DRB1*0405</i> allele.

a<p>Values represent the mean ± SD.</p>b<p>CSF oligoclonal IgG bands (OB) and/or increased IgG index (upper normal limit = 0.658, according to our previous study <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0048592#pone.0048592-Kira2" target="_blank">[21]</a>.</p>c<p>Brain MRI lesions that meet the Barkhof criteria <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0048592#pone.0048592-Barkhof1" target="_blank">[29]</a>.</p><p>EDSS, Kurtzke’s Expanded Disability Status Scale; LESCLs, longitudinally extensive spinal cord lesions extending over three or more vertebral segments; MS, multiple sclerosis; OB, oligoclonal IgG bands.</p><p>p^uncorr was corrected by multiplying the value by nine to calculate p^corr.</p