Resonant tunneling driven metal-insulator transition in double quantum-well structures of strongly correlated oxide.

The metal-insulator transition (MIT), a fascinating phenomenon occurring in some strongly correlated materials, is of central interest in modern condensed-matter physics. Controlling the MIT by external stimuli is a key technological goal for applications in future electronic devices. However, the standard control by means of the field effect, which works extremely well for semiconductor transistors, faces severe difficulties when applied to the MIT. Hence, a radically different approach is needed. Here, we report an MIT induced by resonant tunneling (RT) in double quantum well (QW) structures of strongly correlated oxides. In our structures, two layers of the strongly correlated conductive oxide SrVO3 (SVO) sandwich a barrier layer of the band insulator SrTiO3. The top QW is a marginal Mott-insulating SVO layer, while the bottom QW is a metallic SVO layer. Angle-resolved photoemission spectroscopy experiments reveal that the top QW layer becomes metallized when the thickness of the tunneling barrier layer is reduced. An analysis based on band structure calculations indicates that RT between the quantized states of the double QW induces the MIT. Our work opens avenues for realizing the Mott-transistor based on the wave-function engineering of strongly correlated electrons.

Dielectric collapse at the LaAlO3/SrTiO3 (001) heterointerface under applied electric field.

The fascinating interfacial transport properties at the LaAlO3/SrTiO3 heterointerface have led to intense investigations of this oxide system. Exploiting the large dielectric constant of SrTiO3 at low temperatures, tunability in the interfacial conductivity over a wide range has been demonstrated using a back-gate device geometry. In order to understand the effect of back-gating, it is crucial to assess the interface band structure and its evolution with external bias. In this study, we report measurements of the gate-bias dependent interface band alignment, especially the confining potential profile, at the conducting LaAlO3/SrTiO3 (001) heterointerface using soft and hard x-ray photoemission spectroscopy in conjunction with detailed model simulations. Depth-profiling analysis incorporating the electric field dependent dielectric constant in SrTiO3 reveals that a significant potential drop on the SrTiO3 side of the interface occurs within ~2 nm of the interface under negative gate-bias. These results demonstrate gate control of the collapse of the dielectric permittivity at the interface, and explain the dramatic loss of electron mobility with back-gate depletion.

Self-energy on the low- to high-energy electronic structure of correlated metal SrVO3.

The correlated electronic structure of SrVO(3) has been investigated by angle-resolved photoemission spectroscopy using in situ prepared thin films. Pronounced features of band renormalization have been observed: a sharp kink ∼60 meV below the Fermi level (E(F)) and a broad so-called "high-energy kink" ∼0.3 eV below E(F) as in the high-T(c) cuprates, although SrVO(3) does not show magnetic fluctuations. We have deduced the self-energy in a wide energy range by applying the Kramers-Kronig relation to the observed spectra. The obtained self-energy clearly shows a large energy scale of ∼0.7 eV, which is attributed to electron-electron interaction and gives rise to the ∼0.3 eV kink in the band dispersion as well as the incoherent peak ∼1.5 eV below E(F). The present analysis enables us to obtain a consistent picture for both the incoherent spectra and the band renormalization.

Association of the HLA-DPB1*0501 allele with anti-aquaporin-4 antibody positivity in Japanese patients with idiopathic central nervous system demyelinating disorders.

There are two subtypes of multiple sclerosis (MS) in Asians: the opticospinal (OSMS) form that shows a selective involvement of the optic nerve and the spinal cord and the conventional (CMS) form that has disseminated lesions in the central nervous system including the cerebrum, cerebellum and brainstem. Both show distinct human leukocyte antigen (HLA) class II associations. OSMS has similar features to the relapsing form of neuromyelitis optica (NMO) in Western populations. Recently, it was shown that antibodies to aquaporin-4 (AQP4) are specifically detected in NMO patients and in some Japanese patients with OSMS or recurrent optic neuritis or myelitis. To clarify the immunogenetic background of anti-AQP4 antibody production, we studied HLA-DRB1 and -DPB1 gene polymorphisms in anti-AQP4 antibody-positive and -negative patients with idiopathic demyelinating diseases, such as MS, recurrent optic neuritis and recurrent myelitis. The phenotypic frequency of the HLA-DPB1*0501 allele was significantly increased in anti-AQP4 antibody-positive patients (89.5%, odds ratio = 4.8; 95% confidence interval = 1.6-14.3, n = 38, P(corr) = 0.032) compared with controls (64.0%, n = 125) but not in either anti-AQP4 antibody-negative OSMS (75.0%, n = 32) or CMS (69.2%, n = 52) patients. There was no significant correlation between any HLA-DRB1 allele and the existence of anti-AQP4 antibody. These findings suggest that the emergence of anti-AQP4 antibody is reinforced by the presence of the HLA-DPB1*0501 allele in Japanese.

Hypercomplementemia at relapse in patients with anti-aquaporin-4 antibody.

OBJECTIVE: Because Asian patients with opticospinal multiple sclerosis (OSMS) frequently have anti-aquaporin-4 (AQP4) antibody, complement-mediated disruption of astrocyte foot processes is proposed but not yet proven. We aimed to clarify whether complement consumption occurs at relapse in anti-AQP4 antibody-positive patients. METHODS: We analyzed serum CH50, C3, C4, and C-reactive protein (CRP) levels and their relation to clinical phases in 118 MS patients with or without anti-AQP4 antibody. Serum CH50 levels were higher in 24 patients with anti-AQP4 antibody than in 39 OSMS and 54 conventional form of MS (CMS) patients without anti-AQP4 antibody at relapse (Pcorr<0.05) but not in remission. The frequency of hypercomplementemia at relapse was also higher in anti-AQP4 antibody-positive patients than in anti-AQP4 antibody-negative CMS patients (70.4% vs 29.0%, Pcorr<0.05). C3 and C4 levels did not differ significantly among the three groups at relapse. In patients with anti-AQP4 antibody, the coexistence of hypercomplementemia and high CRP values was more common at relapse than in the remission phase (36.0% vs 10.5%, P<0.05). In patients with extensive central nervous system lesions, hypercomplementemia was significantly more common in anti-AQP4 antibody-positive patients than anti-AQP4 antibody-negative ones (88.9% vs 16.7%, P<0.01). We consider that hypercomplementemia in anti-AQP4 antibody-positive patients may reflect a systemic inflammatory reaction at relapse.

Association of the HLA-DRB1 alleles with characteristic MRI features of Asian multiple sclerosis.

BACKGROUND: In Asian patients with multiple sclerosis (MS), a paucity of brain lesions and longitudinally extensive spinal cord lesions (LESCLs) extending three or more vertebral segments are characteristic findings on magnetic resonance imaging (MRI). We aimed to disclose possible factors contributing to the development of such MRI features. METHOD: Genotyping of HLA-DRB1 and -DPB1 alleles was performed in 121 consecutive Japanese patients with clinically definite MS based on the Poser criteria and 125 healthy controls. Possible factors associated with MRI features were determined by multiple logistic analysis. Patients with MS were classified based on the presence or absence of brain lesions fulfilling the Barkhof criteria (Barkhof brain lesions) and LESCLs. Barkhof brain lesion-negative (-) patients had a markedly lower frequency of HLA-DRB1*0901 than controls (P(corr) < 0.05), whereas the frequency of DRB1*1501 was increased in the Barkhof brain lesion-positive (+) group, although this increase was not significant after correction. No Barkhof(-)LESCL(+) patients carried DRB1*0901 (P(corr) < 0.05), despite this being the most common allele in Japanese. The Barkhof(-)LESCL(-) group showed a significant increase in the frequency of DRB1*0405 compared with controls (P(corr) < 0.05). None of the DPB1 alleles were significantly different among the groups. Using multiple logistic analysis, the absence of oligoclonal bands was positively associated with an absence of Barkhof brain lesions, whereas a higher EDSS score was positively associated with the presence of LESCLs; however, the presence of anti-aquaporin-4 antibodies was not associated with either feature. CONCLUSION: The characteristic MRI features in Asians are partly related to distinct HLA-DRB1 gene alleles and an absence of oligoclonal bands.

Distinct CSF cytokine/chemokine profiles in atopic myelitis and other causes of myelitis.

BACKGROUND: We reported the emergence of a distinct myelitis in patients with atopic diathesis (atopic myelitis [AM]) by a nationwide survey throughout Japan. Similar cases have recently been reported in Caucasians. Pathologic studies of biopsied spinal cord specimens revealed chronic active inflammation with eosinophilic infiltration. OBJECTIVE: To clarify the cytokine/chemokine alterations in CSF from patients with AM in comparison to other causes of myelitis. METHODS: We measured 27 cytokines, chemokines, and growth factors simultaneously in CSF from 22 patients with AM, 20 with opticospinal multiple sclerosis (OSMS), 11 with HTLV-1-associated myelopathy (HAM), 9 with Sjögren syndrome-related myelitis (SM), and 20 with other noninflammatory neurologic diseases (OND), using a fluorescent bead-based immunoassay. RESULTS: In patients with AM, CCL11 and interleukin (IL)-9 were significantly increased as compared with patients with OND and other myelitis while in patients with OSMS interferon-gamma and granulocyte-colony stimulating factor levels were significantly higher than in patients with OND and other causes of myelitis. Significant increase of IL-17 in comparison to patients with OND was found only in patients with OSMS, irrespective of presence or absence of anti-aquaporin-4 (AQP4) antibody. In patients with HAM, CXCL10 and CCL5 were higher than in patients with OND and other myelitis. In patients with SM, CCL3 and CCL4 were higher than in patients with OND. In patients with AM, CCL11, IL-9, and IL-1 receptor antagonist (IL-1ra) showed positive correlations with the final Kurtzke Expanded Disability Status Scale scores while IL-1ra and IL-12(p70) had positive correlations with disease duration. CONCLUSION: Intrathecal upregulation of CCL11 and Th2 cytokines is characteristic of atopic myelitis, which is distinct from interleukin-17/interferon-gamma-related autoimmune condition of opticospinal multiple sclerosis.

History of allergic disorders in common neurologic diseases in Japanese patients.

OBJECTIVE: To clarify the association between past and present history of allergic disorders and neurologic diseases. METHODS: The past and present history of common allergic disorders together with family history was prospectively studied in all out-patients at the Department of Neurology at Kyushu University Hospital from March 1998 to February 2000. RESULTS: Among 3113 out-patients, 2152 (69.1%) completed a questionnaire. Myelitis showed a statistically significant increase of concomitant atopic dermatitis (P=0.006) and concomitant and past atopic dermatitis (P=0.014), as compared with neurologically healthy controls. Moreover, patients with lower motoneuron disease (LMND) had a statistically significant increase of past and concomitant asthma (P=0.007). None of the other common neurologic diseases showed any increase of allergic disorders when compared with controls. CONCLUSIONS: The present study supports the significant association between allergic disorders and such spinal cord diseases as myelitis and LMND in Japanese patients.

Th2 shift in mononeuritis multiplex and increase of Th2 cells in chronic inflammatory demyelinating polyneuropathy: an intracellular cytokine analysis.

To elucidate the T helper 1 (Th1)/T helper 2 (Th2) balance in various inflammatory neuropathies, we measured the ratio of intracellular interferon-gamma (IFN-gamma)-positive to IL-4-positive cells (intracellular IFN-gamma/IL-4 ratio) by flow cytometry in peripheral blood CD4(+) T cells of 14 patients with mononeuritis multiplex (MNM), 12 patients with chronic inflammatory demyelinating polyneuropathy (CIDP), 10 patients with Guillain-Barré syndrome (GBS), 23 patients with neurodegenerative disorders and 36 healthy controls by intracellular labeling. The patients with MNM showed a significantly lower intracellular IFN-gamma/IL-4 ratio (P<0.05) and higher IL-4(+)/IFN-gamma(-) cell percentages (P<0.05) than the controls. The increase of IL-4(+)/IFN-gamma(-) cell percentages was especially prominent in MNM of unknown etiology (P<0.005). The patients with CIDP also showed significantly higher IL-4(+)/IFN-gamma(-) cell percentages (P<0.05) than the controls. The IL-4(+)/IFN-gamma(-) cell percentages were increased in some patients with GBS, but the difference was not significant compared with the controls. Thus, our results suggest that a Th2 shift is a characteristic of MNM and may play an important role in the development of the disease.

Tc1/Tc2 and Th1/Th2 balance in Asian and Western types of multiple sclerosis, HTLV-I-associated myelopathy/tropical spastic paraparesis and hyperIgEaemic myelitis.

CD8+ T cells, like CD4+ T cells, can differentiate into at least two subsets with distinct cytokine patterns: Tc1 cells produce Th1-like cytokines and Tc2 cells produce Th2-like cytokines. To clarify the immunopathological roles of Tc1 and Tc2 cells in central nervous system (CNS) inflammation, we examined intracellular cytokines in CD8+ and CD4+ T cells by flow cytometry and analyzed the Tc1/Tc2 balance as well as the Th1/Th2 balance in 80 patients with various CNS inflammatory diseases, including 20 with optico-spinal multiple sclerosis (OS-MS), 21 with conventional MS (C-MS), 22 with human T-lymphotropic virus type I (HTLV-I)-associated myelopathy/tropical spastic paraparesis (HAM/TSP) and 17 with hyperIgEaemic myelitis. Twenty-two healthy subjects were also examined as controls. Patients with OS-MS showed a significantly higher percentage of INF-gamma+IL-4- CD8+ T cells as well as CD4+ T cells and a significantly higher intracellular interferon-gamma (IFN-gamma)/interleukin-4 (IL-4) ratio both in CD8+ and CD4+ T cells throughout the relapse and remission phases than the healthy controls. Furthermore, the patients with OS-MS showed a significantly lower percentage of INF-gamma-IL-4+ CD4+ T cells as well as CD8+ T cells during the relapse phase than the healthy controls. On the other hand, the patients with C-MS showed a significantly higher percentage of IFN-gamma-IL-4+ CD8+ T cells in addition to more IFN-gamma+IL-4- CD4+ T cells during the relapse phase than the healthy controls. The HAM/TSP patients showed a significantly higher percentage of INF-gamma+IL-4- CD8+ T cells and a significantly higher intracellular IFN-gamma/IL-4 ratio in CD8+ T cells than the healthy controls. In contrast, in hyperIgEaemic myelitis, in addition to a significantly lower intracellular IFN-gamma/IL-4 ratio in CD4+ T cells, a tendency toward a lower intracellular IFN-gamma/IL-4 ratio in CD8+ T cells in comparison to the healthy controls was observed. These results clarified for the first time the distinct Tc1/Tc2 balance in each disease condition as follows: Tc1 cell response is predominant in OS-MS and HAM/TSP, while Tc2 cell response is predominant in hyperIgEaemic myelitis and at relapse phase of C-MS. Furthermore, our results suggest that CD8+ T cells play an adjunctive role in disease induction and the clinical course of MS.

Differences between T-cell reactivities to major myelin protein-derived peptides in opticospinal and conventional forms of multiple sclerosis and healthy controls.

In Japanese, susceptibility to the conventional form of multiple sclerosis (C-MS) is associated with the HLA-DRB1*1501-DRB5*0101 haplotype while susceptibility to the opticospinal form of MS (OS-MS) is associated with HLA-DPA1*0202-DPB1*0501. To clarify the characteristics of T cells autoreactive to myelin proteins in each MS subtype, we established T-cell lines reactive to such myelin antigens as myelin basic protein (MBP), proteolipid protein (PLP) and myelin oligodendrocyte glycoprotein (MOG) from 5 of 10 OS-MS patients, 6 of 11 C-MS patients and 7 of 13 healthy controls (HCs), and T-cell epitopes and their restriction molecules were determined. We found that (a) intermolecular epitope spreading was found to be significantly more frequent in MS patients than in HCs (P=0.0128), (b) intramolecular epitope spreading also tended to occur more frequently in MS patients than in HCs (P=0.0584), (c) in OS-MS, HLA-DR-restricted and MOG-autoreactive T cells were more frequently established as compared with those reactive to MBP or PLP epitopes and (d) in C-MS, HLA-DQ-restricted and PLP-autoreactive T cells dominated those autoreactive to MBP or MOG epitopes. A DPB1*0501-restricted MBP-reactive T-cell clone from a patient with OS-MS provided evidence that the first HLA class II anchor amino acid of peptide bound to disease-susceptible DP5 molecule was distinct from that for the DR2 molecule. Taken together, these differences in specificities of myelin-autoreactive T cells between C-MS and OS-MS as well as the difference in the anchor motif of the binding peptides between each MS subtype-susceptible HLA class II molecule may contribute to the development of distinct clinical phenotypes.

Myelitis associated with atopic disorders in Japan: a retrospective clinical study of the past 20 years.

OBJECTIVE: To clarify the clinical features of myelitis associated with atopic disorders in Japanese patients. SUBJECTS AND METHODS: We retrospectively studied the clinical, immunological and electrophysiological features of 68 consecutive patients with myelitis of acute or subacute onset diagnosed at Kyushu University Hospital during the past 20 years. RESULTS: While only 2 of 28 (7%) patients with myelitis diagnosed between 1979 and 1993 had either atopic dermatitis (AD) or bronchial asthma (BA), 19 of 40 (48%) patients with myelitis diagnosed between 1994 and 1998 did. Among the 40 patients with myelitis diagnosed between 1994 and 1998, 19 patients with either AD or BA as well as 21 patients without either disease showed a significantly higher level of serum total IgE, higher frequency of hyperIgEaemia and higher frequency of mite antigen-specific IgE than 82 healthy controls. Myelitis patients with AD presenting as persistent paresthesia/dysesthesia in all four limbs showed cervical cord lesions on MRI and abnormalities in upper limb motor evoked potentials but no abnormalities in the cerebrospinal fluid (CSF), while myelitis patients with BA showed preferential involvement of the lower motor neurons clinically and electromyographically. In addition, 12 patients with myelitis who had hyperIgEaemia and mite antigen-specific IgE but neither AD nor BA showed incomplete transverse myelitis with mild motor disability and few CSF abnormalities. CONCLUSION: The clinical features of myelitis associated with atopic disorders were in part distinguished by the type of preceding atopic disorder, and also were different from those of hyperIgEaemic myelitis with no preceding atopic disorders.

High-dose vitamin C therapy for inclusion body myositis.

OBJECTIVES: The efficiency of high-dose vitamin C therapy for inclusion body myositis (IBM) was assessed. SUBJECTS & METHODS: The subjects were five patients with IBM confirmed pathologically. After the intravenous administration of 40 mg/kg vitamin C five times/week for four weeks, muscle weakness was found to improve in three cases. The average muscle score improved from 8.1 to 8.8, from 7.0 to 8.1 and from 6.2 to 6.8. Magnetic resonance imaging (MRI) demonstrated a reduction in the size of T2 high lesions and gadolinium enhancement in the thigh muscles in one case. Based on our findings, high-dose vitamin C therapy is considered to be effective in some cases of IBM.

Flow cytometric differentiation of Asian and Western types of multiple sclerosis, HTLV-1-associated myelopathy/tropical spastic paraparesis (HAM/TSP) and hyperIgEaemic myelitis by analyses of memory CD4 positive T cell subsets and NK cell subsets.

We examined the alterations of memory CD4(+) T cell subsets bearing surface receptors linked to either Th1 or Th2 cytokine production as well as natural killer (NK) cell subsets by three color flow cytometry in the peripheral blood from 36 patients with clinically definite multiple sclerosis (MS), 27 patients with HAM/TSP, 13 patients with hyperIgEaemic myelitis who had mite antigen-specific IgE and 25 healthy controls (HC). The patients with MS were clinically classified into an optico-spinal form of MS (Asian type, MS-A) and the conventional form of MS (Western type, MS-W). MS-A showed a significant increase of CD4(+)CD45RA(-)CCR5(+) cells (Th1 cells) through the relapse and remission phases in comparison to HC, while MS-W showed a significant increase of CD4(+)CD45RO(+)CD62L(-) cells (Th1 cells) only at the relapse phase. HAM/TSP showed a significant increase of CCR5(+) and CD62L(-) memory CD4(+) T cells as well as CD30(+) memory CD4(+) T cells (Th2 cells) in comparison to HC. On the other hand, a selective increase of CD4(+)CD45RO(+)CD30(+) cells was found in hyperIgEaemic myelitis. The percentage of mature NK cells (CD3(-)CD16(+)CD56(+) cells) as well as double negative T cells (CD3(+)CD4(-)CD8(-) cells) decreased significantly in HAM/TSP in comparison to HC. Our findings therefore suggest a flow cytometric analysis of Th1/Th2-associated markers on memory CD4(+) T cells as well as NK cell subsets to be useful for differentiating various inflammatory neurologic conditions.

Hyperprolactinemia in optico-spinal multiple sclerosis.

OBJECTIVE: To clarify the clinical features of MS patients with hyperprolactinemia. SUBJECTS AND METHODS: The serum prolactin level was measured in 67 Japanese patients (19 men and 48 women) with multiple sclerosis (MS) and in 16 patients (4 men and 12 women) with HTLV-I-associated myelopathy/tropical spastic paraparesis (HAM/TSP) using a two-site immunoradiometric assay. RESULTS: In the MS patients, 32 were classified as having Asian type MS showing a selective involvement of the optic nerves and spinal cord, while the other 35 were classified as having Western type MS which displayed disseminated central nervous system involvement. In women, the serum prolactin level was found to be significantly higher only in Asian type MS (mean=23.1 ng/ml, n=25) than in HAM/TSP (mean=6.9 ng/ml, n=12) (p=0.0297), while it did not differ significantly in men among the three groups. Hyperprolactinemia was significantly associated with acute relapse involving the optic nerves. All MS patients with hyperprolactinemia (7 women with Asian type MS and 2 women with Western type MS) showed recurrent opticomyelitis either throughout or in the early course of the disease, and also had a higher age of onset, a higher Expanded Disability Status Scale score, a greater visual impairment, and higher cell counts and protein contents in the cerebrospinal fluid than did the normoprolactinemic patients. CONCLUSION: Hyperprolactinemia may be one of the characteristic features of Asian patients with MS who preferentially show the optic nerve involvement.

Both the HLA-CPB1 and -DRB1 alleles correlate with risk for multiple sclerosis in Japanese: clinical phenotypes and gender as important factors.

The purpose of this study was to clarify the association of HLA-DRB1 and -DPB1 alleles with multiple sclerosis (MS) in Japanese, to determine whether optico-spinal MS (OS-MS) and conventional MS are immunogenetically distinct, and to verify the role of gender difference in HLA associations of MS. We studied HLA-DRB1 and -DPB1 polymorphisms in 166 Japanese patients with MS. Forty-seven patients were classified as having the optico-spinal MS (OS-MS) and 119 as having conventional MS. A lack of DPB1*0301 and a higher frequency of DPB1*0501 compared with controls (corrected P<0.0074; odds ratio=9.48) were found in OS-MS. By contrast, we found for the first time an association of DPB1*0301 with conventional MS in Japanese (corrected P=0.0444; odds ratio=3.28). Logistic analysis, adjusted for sex and age, revealed independent associations of DPB1*0301 (P=0.0004, adjusted odds ratio (aOR)=4.70), DPB1*0501 (P=0.0081, aOR= 2.50) and DRB1*1501 (P=0.0252, aOR=2.21) with conventional MS. However, the frequencies of DRB1*1501 and DPB1*0501 in male patients with conventional MS were equal to those in male controls while the DPB1*0301 frequency was increased in both male and female patients. We did not find any association of these HLA alleles with disease course and severity. In conclusion, OS-MS is a DPB1*0501-associated distinct subtype of MS, and DPB1*0301 is the most strongly associated allele with conventional MS in Japanese. In addition, gender plays an important role in HLA association with MS.

Th1 dominance in HAM/TSP and the optico-spinal form of multiple sclerosis versus Th2 dominance in mite antigen-specific IgE myelitis.

To clarify the Th1/Th2 balance in spinal cord inflammation, we used ELISA to measure the total and allergen-specific IgE in 69 patients with clinically definite multiple sclerosis (MS), including 24 patients with the optico-spinal form of MS, 45 with HAM/TSP, 30 HTLV-I carriers without HAM/TSP, 40 patients with acute myelitis, 43 with neurodegenerative disorders, and 42 healthy subjects, and flow cytometry to study the intracellular IFNgamma-positive versus IL-4-positive cell ratio (intracellular IFNgamma/IL-4 ratio) in peripheral blood CD4(+) T cells in 40 patients with MS, including 17 patients with the optico-spinal form of MS, 23 with HAM/TSP, 22 with acute myelitis, 23 with neurodegenerative disorders, and 36 healthy subjects. Patients with HAM/TSP showed a significantly higher intracellular IFNgamma/IL-4 ratio, lower IL-4(+)/IFN-gamma(-) cell percentages, lower total IgE level, and lower frequency of cedar pollen-specific IgE than did the controls. The patients with optico-spinal MS showed a significantly higher intracellular IFNgamma/IL-4 ratio and higher IL-4(-)/IFN-gamma(+) cell percentages than the controls even at remission or in the convalescence phase. In contrast, in the patients with acute myelitis, the total serum IgE level and the frequency of mite antigen-specific IgE were significantly elevated in comparison to the controls, while those having mite antigen-specific IgE myelitis showed a significantly lower IFNgamma/IL-4 ratio in the CD4(+) T cells in comparison to the controls. These findings suggest that the Th1 cell response is predominant in HAM/TSP and optico-spinal MS, whereas the Th2 cell response is predominant in mite antigen-specific IgE myelitis.

HLA-DPB1*0501-associated opticospinal multiple sclerosis: clinical, neuroimaging and immunogenetic studies.

In order to clarify the relationship between the clinical phenotype and the human leucocyte antigen (HLA) in multiple sclerosis in Asians, 93 Japanese patients with clinically definite multiple sclerosis underwent clinical MRI and HLA-DPB1 gene typing studies. According to a neurological examination, 29 patients were classified as opticospinal multiple sclerosis, 17 as spinal multiple sclerosis and 47 as Western type multiple sclerosis showing the involvement of multiple sites in the CNS including either the cerebrum, cerebellum or brainstem. The opticospinal multiple sclerosis showed a significantly higher age of onset, higher expanded disability status scale scores and higher CSF cell counts and protein content than the Western type multiple sclerosis. On brain and spinal cord MRI, the opticospinal multiple sclerosis showed a significantly lower number of brain lesions, but a higher frequency of gadolinium-enhancement of the optic nerve and a higher frequency of spinal cord atrophy than in Western type multiple sclerosis. The frequency of the HLA-DPB1*0501 allele was found to be significantly greater in opticospinal multiple sclerosis (93%) than in healthy controls (63%, corrected P value = 0.0091 and relative risk = 7.9), but not in Western type multiple sclerosis (66%) or spinal multiple sclerosis (82%). The marked differences in the clinical and MRI findings as well as in the immunogenetic backgrounds between the opticospinal multiple sclerosis and Western-type multiple sclerosis together suggest that HLA-DPB1*0501-associated opticospinal multiple sclerosis is a distinct subtype of multiple sclerosis.