Minocycline suppresses experimental autoimmune encephalomyelitis by increasing tissue inhibitors of metalloproteinases.

Matrix metalloproteinases (MMPs) that are secreted by activated T cells play a significant role in degradation of the extracellular matrix around the blood vessels and facilitate autoimmune neuroinflammation; however, it remains unclear how MMPs act in lesion formation and whether MMP-targeted therapies are effective in disease suppression. In the present study, we attempted to treat experimental autoimmune encephalomyelitis (EAE) by administration of small interfering RNAs (siRNAs) for MMP-2, MMP-9, and minocycline, all of which have MMP-inhibiting functions. Minocycline, but not siRNAs, significantly suppressed disease development. In situ zymography revealed that gelatinase activities were almost completely suppressed in the spinal cords of minocycline-treated animals, while significant gelatinase activities were measured in the EAE lesions of control animals. However, MMP-2 and MMP-9 mRNAs and proteins in the spinal cords of treated rats were unexpectedly upregulated. At the same time, mRNA for tissue inhibitors of MMPs (TIMP)-1 and -2 were also upregulated. The EnzChek Gelatinase/Collagenase assay using tissue containing native MMPs and TIMPs demonstrated that gelatinase activity levels in the spinal cords of treated rats were suppressed to the same level as those in normal spinal cord tissues. Finally, double immunofluorescent staining demonstrated that MMP-9 immunoreactivities of treated rats were almost the same as those of control rats and that MMP-9 and TIMP-1 immunoreactivities were colocalized in the spinal cord. These findings suggest that minocycline administration does not suppress MMPs at mRNA and protein levels but that it suppresses gelatinase activities by upregulating TIMPs. Thus, MMP-targeted therapies should be designed after the mechanisms of candidate drugs have been considered.

Characterization of fibrosis-promoting factors and siRNA-mediated therapies in C-protein-induced experimental autoimmune myocarditis.

Due to poor proliferation abilities of cardiomyocytes, the repair process in the heart after insults is often associated with fibrosis formation. In this study, we characterized inflammation and/or fibrosis-related molecules in the heart with experimental autoimmune carditis. Immunohistochemical examinations reveled that expression of tenascin-C (TNC), matrix metalloproteinase-9 (MMP-9), transforming growth factorß1 (TGF-ß1), connective tissue growth factor (CTGF) and α smooth muscle cell actin (αSMA) peaked at 2 weeks post-immunization but only TGF-ß1 expression was sustained at 8 weeks. Administration of siRNAs for MMP-2 (siMMP-2) and for MMP-9 (siMMP-9) alone did not modulate inflammation and fibrosis. In contrast, simultaneous administration of siMMP-2 and siMMP-9 significantly reduced inflammation and fibrosis. Of note, siRNA treatment for TGF-ß1, which is an anti-inflammatory cytokine, increased inflammation and decreased fibrosis. These findings suggest that in case of diseases characterized by initial inflammation and subsequent fibrosis, immunotherapies should target inflammation, not fibrosis, because the latter therapies exacerbate inflammation.

Definitive engagement of cytotoxic CD8 T cells in C protein-induced myositis, a murine model of polymyositis.

OBJECTIVE: To substantiate a pathogenic role of cytotoxic CD8 T cells in the development of a murine polymyositis model, C protein-induced myositis (CIM). METHODS: Beta(2)-microglobulin-null mutant, perforin-null mutant, and wild-type (WT) C57BL/6 mice were immunized with skeletal muscle C protein fragments to provoke CIM. Regional lymph node CD8 or CD4 T cells stimulated with C protein-pulsed dendritic cells were transferred adoptively to naive mice. Inflammation and damage of the muscle tissues were evaluated histologically. RESULTS: The incidence of myositis development was significantly lower in ß2-microglobulin-null and perforin-null mutant mice compared with WT mice. Inflammation was less severe in mutant mice, and the incidence of muscle injury was reduced significantly. Adoptive transfer of lymph node T cells from mice with CIM induced myositis in naive recipient mice. The CD8 T cell-induced muscle injuries were significantly more severe than the CD4 T cell-induced muscle injuries. CONCLUSION: Perforin-mediated cytotoxicity by CD8 T cells is definitively responsible for muscle injury in CIM.

Matrix metalloproteinase (MMP)-9, but not MMP-2, is involved in the development and progression of C protein-induced myocarditis and subsequent dilated cardiomyopathy.

Repeated or continuous inflammation of the heart is one of the initiation factors for dilated cardiomyopathy (DCM). In previous studies, we established a DCM animal model by immunizing rats with cardiac C protein. In the present study, we analyze the role of matrix metalloproteinases (MMPs) in experimental autoimmune carditis (EAC) and subsequent DCM to elucidate the pathomechanisms of this disease. In this model, inflammation begins approximately 9 days after immunization. At that time, MMP activities were detected by in situ zymography. Real-time PCR analysis revealed continuous up-regulation of MMP-2 mRNA from 2 wk and thereafter. MMP-9 mRNA, however, had only a transient increase at 2 wk. Double staining with in situ zymography and cell markers demonstrated that gelatinase (MMP-2 and MMP-9)-expressing cells are infiltrating macrophages during the early stage and cardiomyocytes at later stages. Minocycline, which inhibits MMP-9 activities more strongly than MMP-2, significantly suppressed EAC, but an MMP-2-specific inhibitor, TISAM, did not affect the course of the disease. Furthermore, immunohistochemical examination revealed that minocycline treatment suppressed T cell and macrophage infiltration strongly, whereas TISAM did not. These findings indicate that MMP-9, but not MMP-2, is involved in the pathogenesis of the acute phase of EAC, and further suggest that MMP-9 inhibitors, minocycline and its derivatives, may be useful therapies for EAC and DCM.

Intravenous immunoglobulin therapy prevents development of autoimmune encephalomyelitis and suppresses activation of matrix metalloproteinases.

Although intravenous immunoglobulin (IVIG) has been reported to improve the status of expanded disability status scale (EDSS) of multiple sclerosis (MS) patients and reduce the annual relapse rate, some studies did not find its beneficial effects. In the present study, using an animal model for MS, we found that prophylactic, but not therapeutic, treatment successfully suppressed the disease development. During the search for factors involved in the disease suppression by IVIG, we obtained evidence suggesting that IVIG exerts its function, at least in part, by suppressing activation of matrix metalloproteinases (MMP)-2 and -9. Gelatin zymography revealed that gelatinase activities were suppressed by IVIG treatment in the spinal cord, but not in plasma. This finding raises the possibility that IVIG blocks MMP activities at the interface between the blood stream and CNS. With in situ zymography, we also observed that gelatinase activities were expressed mainly in astrocytes in the inflamed spinal cord of control rats and that this expression was attenuated by the treatment. These findings provide useful information to set optimal conditions for IVIG treatment of MS and to obtain more beneficial effects.

Autoantibodies recognizing native MOG are closely associated with active demyelination but not with neuroinflammation in chronic EAE.

It is important to find biomarkers for autoimmune inflammation and demyelination in the CNS to monitor disease status in patients with multiple sclerosis (MS). For this purpose, we determined the titers of antibodies (Ab) reacting with native myelin oligodendrocyte glycoprotein (MOG)-expressing cells to evaluate the disease activity of chronic experimental autoimmune encephalomyelitis (EAE) in rats and the relationship between anti-MOGcme (cell membrane-expressed MOG), Ab titers and clinical and pathological parameters were evaluated. Consequently, we found that elevation of anti-MOGcme Ab titers was associated with clinical severity, except for some cases in very late stages and with severe and widespread demyelination but with dominant inflammation. In contrast, antibodies detected by standard ELISA using recombinant MOG were elevated in both symptomatic and asymptomatic rats and were not associated with parameters such as inflammation and demyelination. Longitudinal examination of anti-MOGcme Ab titers in individual rats revealed that Ab titers accurately reflect disease activity. Furthermore, anti-MOGcme Ab titer was not elevated in acute EAE without demyelination. These findings suggest that autoantibodies reacting with native and glycosylated MOG play an important role in the progression of demyelinating diseases and could be biomarkers for monitoring the status of patients with MS.

Glial cell line-derived neurotrophic factor is expressed by inflammatory cells in the sciatic nerves of Lewis rats with experimental autoimmune neuritis.

Neurotrophic factors, including glial cell line-derived neurotrophic factor (GDNF), have been known to play a role in neuroprotection in the injured peripheral nervous system (PNS). To evaluate the involvement of GDNF in experimental autoimmune neuritis (EAN) pathogenesis, the expression of GDNF in rat sciatic nerves with EAN was studied. Western blot analysis showed that the level of GDNF protein significantly increased 1.8-fold at the paralytic stage of EAN at day 12 post-immunization (PI) (p < 0.01), and its level further increased approximately 2.5-fold at day 21 PI (p < 0.001) in the sciatic nerves of EAN-affected rats compared with those of control rats, and then declined thereafter at day 28 PI. Immunohistochemical analysis showed that axons and Schwann cells constitutively contained GDNF in normal controls. In sciatic nerves with EAN at day 12 PI, GDNF was immunostained in infiltrating inflammatory cells including macrophages and T cells. Collectively, we postulate that GDNF plays a regulatory role in EAN paralysis. A paradoxical role of inflammatory cells to ameliorate PNS inflammation remains to be further studied in EAN, an animal model of human demyelinating disease.

Role of pathogenic T cells and autoantibodies in relapse and progression of myelin oligodendrocyte glycoprotein-induced autoimmune encephalomyelitis in LEW.1AV1 rats.

Accumulating evidence suggests that T cells and autoantibodies reactive with myelin oligodendrocyte glycoprotein (MOG) play a critical role in the pathogenesis of multiple sclerosis (MS). In the present study, we have tried to elucidate the pathomechanisms of development and progression of the disease by analysing T cells and autoantibodies in MOG-induced rat experimental autoimmune encephalomyelitis (EAE), which exhibits various clinical subtypes mimicking MS. Analysis using overlapping peptides revealed that encephalitogenic epitopes resided in peptide 7 (P7, residue 91-108) and P8 (residue 103-125) of MOG. Immunization with MOGP7 and MOGP8 induced relapsing-remitting or secondary progressive EAE. T cells taken from MOG-immunized and MOGP7-immunized rats responded to MOG and MOGP7 and sera from MOG-immunized rats reacted to MOG and MOGP1. Significant epitope spreading was not observed at either T-cell or antibody levels. Interestingly, sera from MOGP7-immunized rats with clinical signs did not react to MOG and MOG peptides throughout the observation period, suggesting that disease development and relapse in MOGP7-induced EAE occur without autoantibodies. However, MOGP7 immunization with adoptive transfer of anti-MOG antibodies aggravated the clinical course of EAE only slightly. Analysis of antibodies against conformational epitope (cme) suggests that anti-MOG(cme) may play a role in the pathogenicity of anti-MOG antibodies. Collectively, these findings demonstrated that relapse of a certain type of MOG-induced EAE occurs without autoantibodies but that autoantibodies may play a role in disease progression. Relapses and the progression of MS-mimicking EAE are differently immunoregulated so immunotherapy should be designed appropriately on the basis of precise information.

Characterization of CD8-positive macrophages infiltrating the central nervous system of rats with chronic autoimmune encephalomyelitis.

CD8+ macrophages appear in the central nervous system (CNS) under various pathological conditions such as trauma and ischemia. Furthermore, macrophages expressing CD8 were found in CNS lesions of chronic, but not acute, experimental autoimmune encephalomyelitis (EAE). To further characterize cells with this phenotype, we examined CD8+ macrophages/monocytes in the CNS and peripheral organs during the course of acute and chronic EAE that had been induced by immunization of rats with myelin basic protein and myelin oligodendrocyte glycoprotein, respectively. Counting CD8+ macrophages in CNS lesions revealed that their numbers increased reaching about 60% of total infiltrating macrophages in chronic EAE, while CD8+ macrophages remained less than 5% throughout the course of acute EAE. Unexpectedly, however, higher abundance of CD8+ monocytes/macrophages in the peripheral blood was found in both acute and chronic EAE. Real-time polymerase chain reaction analysis revealed no significant difference in the levels of chemokines and chemokine receptors of blood CD8+ monocytes between acute and chronic EAE. mRNA expression of perforin, a cytotoxic substance, was up-regulated in CD8+ monocytes compared with that of CD8- monocytes in both acute and chronic EAE. These findings suggest that activated CD8+ macrophages may play a cytotoxic role in chronic EAE lesions and that cells other than CD8+ monocytes/macrophages determined the difference in CNS pathology between acute and chronic EAE. Analysis of CD8+ monocytes/macrophages may provide useful information to permit further dissect the pathomechanisms of multiple sclerosis and to develop effective immunotherapies against autoimmune diseases in the CNS.

Recent advance in immunotherapies for Alzheimer disease: with special reference to DNA vaccination.

Alzheimer disease (AD) is the most common cause of dementia characterized by progressive neurodegeneration. Based on the amyloid cascade hypothesis, several immunotherapies for AD have been developed as curative treatment. In 1999, Schenk et al. reported for the first time that amyloid beta (Abeta) deposits in AD model mice could be reduced by active vaccination with Abeta peptide. Although clinical trials with the Abeta peptide were halted due to the development of meningoencephalitis in some treated patients, the vaccine therapy was judged to be effective on the basis of clinical and pathological analyses. Passive immunization using humanized anti-Abeta monoclonal antibodies is also under clinical trials; however they have some problems to be solved. As other strategies, DNA vaccines have been developed as immunotherapies for AD, which is simple, easily modified and can be administered without adjuvant. DNA vaccines were developed by several groups including our laboratory, which induced Abeta reduction in AD model mice without side effects. DNA vaccination may be open up new avenue of vaccine therapies for AD in the near future.

Nonviral DNA vaccination augments microglial phagocytosis of beta-amyloid deposits as a major clearance pathway in an Alzheimer disease mouse model.

Immunotherapies markedly reduce beta-amyloid (Abeta) burden and reverse behavioral impairment in mouse models of Alzheimer disease. We previously showed that new Abeta DNA vaccines reduced Abeta deposits in Alzheimer disease model mice without detectable side effects. Although they are effective, the mechanisms of Abeta reduction by the DNA vaccines remain to be elucidated. Here, we analyzed vaccinated and control Alzheimer disease model mice from 4 months to 15 months of age to assess which of several proposed mechanisms may underlie the beneficial effects of this vaccination. Immunohistochemical analysis revealed that activated microglial numbers increased significantly in the brains of vaccinated mice after DNA vaccination both around Abeta plaques and in areas remote from them. Microglia in treated mice phagocytosed Abeta debris more frequently than they did in untreated mice. Although microglia had an activated morphological phenotype, they did not produce significant amounts of tumor necrosis factor. Amyloid plaque immunoreactivity and Abeta concentrations in plasma increased slightly in vaccinated mice compared with controls at 9 but not at 15 months of age. Collectively, these data suggest that phagocytosis of Abeta deposits by microglia plays a central role in Abeta reduction after DNA vaccination.

Differential effects of decoy chemokine (7ND) gene therapy on acute, biphasic and chronic autoimmune encephalomyelitis: implication for pathomechanisms of lesion formation.

Multiple sclerosis (MS) exhibits several clinical subtypes such as the relapsing-remitting (RR) and secondary progressive (SP) forms. In accordance with this, formation of demyelinating plaques in the central nervous system (CNS) occurs by different mechanisms. In the present study, we induced acute, biphasic and chronic (RR or SP) EAE in rats and examined the effects of decoy chemokine (7ND) gene therapy, which inhibits the migration of macrophages, to address the above issue. Interestingly, it was demonstrated that the clinical signs of acute EAE and the first attack of biphasic EAE were minimally affected, whereas chronic EAE and the relapse of biphasic EAE were completely suppressed with 7ND treatment. In the CNS, the number of infiltrating macrophages was reduced in all the stages of the three types of EAE. These findings suggest that in acute EAE and in the first attack of biphasic EAE, where anti-macrophage migration therapy was almost ineffective, pathogenic T cells are mainly involved in lesion formation. In contrast, the relapse of biphasic EAE and chronic EAE macrophages play a major role in the disease process. Thus, the mechanisms of lesion formation are not uniform and immunotherapy should be performed on the basis of information about the pathomechanisms of autoimmune diseases.

DNA vaccine therapy for Alzheimer's disease: present status and future direction.

Alzheimer's disease is the most common cause of dementia characterized by progressive neurodegeneration. Based on the amyloid cascade hypothesis, a vaccine therapy for Alzheimer's disease (AD) was developed as a curative treatment. In 1999, the amyloid beta (Abeta) reduction in AD model transgenic mice with active vaccination with Abeta peptide was first reported. Although the clinical trials of active vaccination for AD patients were halted due to the development of meningoencephalitis in some patients, from the analysis of the clinical and pathological findings of treated patients, the vaccine therapy is thought to be effective. Based on such information, the vaccines for clinical application of human AD have been improved to control excessive immune reaction. Recently, we have developed non-viral DNA vaccines and obtained substantial Abeta reduction in transgenic mice without side effects. DNA vaccines have many advantages over conventional active or passive immunization. In this article, we review conventional vaccine therapies and further explain our non-viral DNA vaccine therapy. Finally, we show some data regarding the mechanisms of Abeta reduction after administration of DNA vaccines. DNA vaccination may open up new avenues of vaccine therapy for AD.

Paralysis of CD4(+)CD25(+) regulatory T cell response in chronic autoimmune encephalomyelitis.

Increasing evidence strongly suggest that CD4(+)CD25(+) regulatory T (Treg) cells play a pivotal role in suppressing the development of autoimmune diseases. However, it remains poorly understood how these cells are involved in the persistence of, or recovery from, the diseases. In the present study, we examined the role of CD4(+)CD25(+) Treg cells in chronic EAE and compared the results with those obtained in acute EAE. In EAE lesions, CD25(+) cells decreased rapidly at the beginning of chronic EAE, whereas these cells were maintained at high levels during the recovery from acute EAE. The number of Foxp3(+)CD4(+)CD25(+) Treg and levels of Foxp3 mRNA in the lymphoid organ were significantly lower in chronic EAE. Importantly, the regulatory function of individual CD4(+)CD25(+) Treg cells was maintained in animals with chronic EAE. Furthermore, adoptive transfer of activated CD4(+)CD25(+) Treg cells suppressed the development of chronic EAE. These findings suggest that impairment of the CD4(+)CD25(+) Treg response is critical for development of chronic autoimmune diseases, and can be adjustable by autologous Treg transplantation.

Characterization of pathogenic T cells and autoantibodies in C-protein-induced autoimmune polymyositis.

Although autoimmune processes may take place in human polymyositis, little is known with regard to its pathogenesis due to the lack of appropriate animal models. In the present study, we developed experimental autoimmune myositis (EAM) in Lewis rats by immunization with recombinant skeletal C-protein and examined the role of pathogenic T cells and autoantibodies. Using recombinant proteins and synthetic peptides, we demonstrated that skeletal C-protein Fragment 2 (SC2) has the strongest myositis-inducing ability and that myositis-inducing epitope(s) reside within the residues 334-363 of SC2 (SC2P3). However, immunization with SC2P3 induced only mild EAM compared with SC2 immunization. Characterization of T cells and antisera revealed that SC2P3 and SC2P7 contain the B cell epitope, while the T cell epitope resides in SC2P5. Furthermore, anti-SC2, but not anti-SC2P3, antisera contained antibodies against the conformational epitope(s) in the SC2 molecule. However, SC2P3 or SC2P5 immunization plus anti-SC2 antibody transfer aggravated the disease only slightly. These findings suggest that C-protein-induced EAM is formed by activation of C-protein-specific T cells along with antibodies against conformational epitopes in C-protein but that there are undetermined factors related to the disease progression. Further analysis of C-protein-induced EAM will provide useful information to elucidate the pathomechanisms of human polymyositis.

Inhibition of glial cell activation ameliorates the severity of experimental autoimmune encephalomyelitis.

Activated microglia and astrocytes have been implicated in the course of multiple sclerosis (MS) and its animal model: experimental autoimmune encephalomyelitis (EAE). MW01-5-188WH is a novel drug that selectively inhibits glial activation in the central nervous system (CNS). We report here that MW01-5-188WH is effective to ameliorate the severity of myelin oligodendrocyte glycoprotein (MOG)-induced EAE. Daily oral administration of MW01-5-188WH at 5mg/kg body weight reduced the clinical scores of EAE mice while having no influence on the disease incidence or animal mortality. Pathological examination revealed reduced numbers of microglia and astrocytes in the spinal cord of MW01-5-188WH-treated EAE mice. Moreover, MW01-5-188WH suppressed the release of key chemokines, which are involved in MS pathology, from cultured microglia and astrocytes. Taken together, our results indicate that treatments that suppress the activation of microglia and astrocytes should be pursued in future research for their potential as avenues for the treatment of MS.

Development of anti-Abeta vaccination as a promising therapy for Alzheimer's disease.

Alzheimer's disease is the most common cause of dementia characterized by progressive neurodegeneration. Recently, a vaccine therapy for Alzheimer's disease was developed as a curative treatment. Although clinical trials of active vaccination for Alzheimer's disease were halted due to the development of meningoencephalitis in some patients, the clinical and pathological findings of treated patients suggest that the vaccine therapy is effective. Hence, newly designed vaccines are being invented to control excessive T-cell immune reactions after the human clinical trial. In this article, we will review conventional vaccine therapies and newly developed vaccine therapies, mainly DNA vaccines, for possible clinical application in the near future.

Increased phosphorylation of caveolin-1 in the sciatic nerves of Lewis rats with experimental autoimmune neuritis.

The levels of phosphorylated caveolin-1 (p-caveolin-1) were analyzed in the sciatic nerves of Lewis rats with experimental autoimmune neuritis (EAN). Western blot analysis showed that the phosphorylation of caveolin-1 increased significantly in the sciatic nerves of EAN-affected rats at the paralytic stage of EAN on day 14 post-immunization (PI) (P<0.05) and declined slightly thereafter during the recovery stage. Immunohistochemistry showed intense p-caveolin-1 immunostaining in some inflammatory macrophages, as well as in T-cells in individual nerve fascicles at the peak stage of EAN, while p-caveolin-1 was weakly expressed in some of the vascular endothelial cells and Schwann cells of normal sciatic nerves. The inflammatory cells with intense p-caveolin-1 expression in the EAN-affected individual nerve fascicles were not positive for terminal deoxynucleotidyl transferase-mediated dUTP nick end-labeling (TUNEL), while the TUNEL-positive apoptotic cells in the perineurium, where infiltration initially occurred, were weakly positive for p-caveolin-1. Based on these findings, we postulate that caveolin-1 is phosphorylated in inflammatory cells soon after they infiltrate the sciatic nerve, as well as in the perineurium, and that p-caveolin-1 activates intracellular signaling in inflammatory cells, leading to cell death, which ultimately eliminates the infiltrating inflammatory cells from the sciatic nerves of animals with EAN.

Increased phosphorylation of cyclic AMP response element-binding protein in the spinal cord of Lewis rats with experimental autoimmune encephalomyelitis.

To investigate whether the phosphorylation of cyclic AMP response element-binding protein (CREB) is implicated in the pathogenesis of experimental autoimmune encephalomyelitis (EAE), the change in the level of CREB phosphorylation was analyzed in the spinal cord of Lewis rats with EAE. Western blot analysis showed that the phosphorylation of CREB in the spinal cord of rats increased significantly at the peak stage of EAE compared with the controls (p<0.05) and declined significantly in the recovery stage (p<0.05). Immunohistochemistry showed that the phosphorylated form of CREB (p-CREB) was constitutively immunostained in few astrocytes and dorsal horn neurons in the spinal cord of normal rats. In the EAE-affected spinal cord, p-CREB was mainly found in ED1-positive macrophages at the peak stage of EAE, and the number of p-CREB-immunopositive astrocytes was markedly increased in the spinal cord with EAE compared with the controls. Moreover, p-CREB immunoreactivity of sensory neurons, which are closely associated with neuropathic pain, was significantly increased in the dorsal horns at the peak stage of EAE. Based on these results, we suggest that the increased phosphorylation of CREB in EAE lesions was mainly attributable to the infiltration of inflammatory cells and astrogliosis, possibly activating gene transcription, and that its increase in the sensory neurons in the dorsal horns is involved in the generation of neuropathic pain in the rat EAE model.

Interferon beta-1b exacerbates multiple sclerosis with severe optic nerve and spinal cord demyelination.

To evaluate the effect of interferon beta-1b (IFNB-1b) on multiple sclerosis (MS) with severe optic nerve and spinal cord demyelination, we examined the relationship between IFNB-1b treatment outcome and the clinical and genetic characteristics of three types of demyelinating diseases of the central nervous system, i.e., neuromyelitis optica (NMO), MS and MS with severe optic-spinal demyelination. Japanese MS frequently carried HLA DPB1*0501, which is associated with NMO. MS with DPB1*0501 showed severe optic-spinal demyelination represented by longitudinally extensive spinal cord lesion, blindness and CSF pleocytosis. IFNB-1b treatment did not succeed in these patients because of the increase of optic nerve and spinal cord relapse and other severe side effects. IFNB-1b should not be administered to demyelinating patients with genetic and clinical characteristics mimicking NMO such as HLA DPB1*0501 allele, longitudinally extensive spinal cord lesion, blindness and CSF pleocytosis even if they have symptomatic cerebral lesions as typically seen in MS. The present study strongly suggests that these patients should be diagnosed as having NMO.