Since its initial reports in the 19th century, neuromyelitis optica (NMO) had been thought to involve only the optic nerves and spinal cord. However, the discovery of highly specific antiaquaporin-4 antibody diagnostic biomarker for NMO enabled recognition of more diverse clinical spectrum of manifestations. Brain MRI abnormalities in patients seropositive for anti-aquaporin-4 antibody are common and some may be relatively unique by virtue of localization and configuration. Some seropositive patients present with brain involvement during their first attack and/or continue to relapse in the same location without optic nerve and spinal cord involvement. Thus, characteristics of brain abnormalities in such patients have become of increased interest. In this regard, MRI has an increasingly important role in the differential diagnosis of NMO and its spectrum disorder (NMOSD), particularly from multiple sclerosis. Differentiating these conditions is of prime importance because early initiation of effective immunosuppressive therapy is the key to preventing attack-related disability in NMOSD, whereas some disease-modifying drugs for multiple sclerosis may exacerbate the disease. Therefore, identifying the MRI features suggestive of NMOSD has diagnostic and prognostic implications. We herein review the brain, optic nerve, and spinal cord MRI findings of NMOSD. Neuromyelitis optica (NMO) is an inflammatory disease of the CNS that is characterized by severe attacks of optic neuritis (ON) and longitudinally extensive transverse myelitis (LETM). 1The past decade has witnessed dramatic advances in our understanding of NMO. Such advances were initiated by the discovery of the disease-specific autoantibody, NMO-immunoglobulin G (NMO-IgG), and subsequent identification of the main target autoantigen, aquaporin-4 (AQP4), which has distinguished NMO as a distinct disease from multiple sclerosis (MS). 2Current diagnostic criteria, however, still require both ON and myelitis for an NMO diagnosis.3 Nevertheless, the identification of anti-AQP4 antibodies beyond the current diagnostic criteria of NMO indicates a broader clinical phenotype of this disorder, so-called "NMO spectrum disorder" (NMOSD). 4,5 The NMOSD encompasses anti-AQP4 antibody seropositive patients with limited or inaugural forms of NMO and with specific brain abnormalities. It also includes anti-AQP4 antibody seropositive patients with other autoimmune disorders such as systemic

SummaryBurkholderia glumae BGR1 produces a broad-host range phytotoxin, called toxoflavin, which is a key pathogenicity factor in rice grain rot and wilt in many field crops. Our molecular and genetic analyses of toxoflavin-deficient mutants demonstrated that gene clusters for toxoflavin production consist of four transcriptional units. The toxoflavin biosynthesis genes were composed of five genes, toxA to toxE , as Suzuki et al. (2004) reported previously. Genes toxF to toxI , which are responsible for toxoflavin transport, were polycistronic and similar to the genes for resistancenodulation-division (RND) efflux systems. Using Tn 3 -gusA reporter fusions, we found that ToxR, a LysRtype regulator, regulates both the toxABCDE and toxFGHI operons in the presence of toxoflavin as a coinducer. In addition, the expression of both operons required a transcriptional activator, ToxJ, whose expression is regulated by quorum sensing. TofI, a LuxI homologue, was responsible for the biosynthesis of both N -hexanoyl homoserine lactone and Noctanoyl homoserine lactone (C8-HSL). C8-HSL and its cognate receptor TofR, a LuxR homologue, activated toxJ expression. This is the first report that quorum sensing is involved in pathogenicity by the regulation of phytotoxin biosynthesis and its transport in plant pathogenic bacteria.

To evaluate the efficacy and safety of repeated rituximab treatment based on the assessment of peripheral circulating memory B cells over 24 months in patients with relapsing neuromyelitis optica (NMO).

IMPORTANCE A previous 2-year analysis of repeated rituximab treatment in patients with neuromyelitis optica (NMO) revealed significant improvements in relapse rates and disability. We report the findings from the longest follow-up of rituximab treatment in NMO, which provide reassurance regarding the long-term efficacy and safety of rituximab in NMO. OBJECTIVE To report the results of rituximab treatment in patients with relapsing NMO or NMO spectrum disorder (NMOSD) for a median of 60 months. DESIGN, SETTING, AND PARTICIPANTS Retrospective case series in an institutional referral center for multiple sclerosis, including 30 patients with relapsing NMO or NMOSD. INTERVENTIONS After induction therapy, a single infusion of rituximab (375 mg/m 2) as maintenance therapy was administered whenever the frequency of reemerging CD27 + memory B cells in peripheral blood mononuclear cells, as measured with flow cytometry, exceeded 0.05% in the first 2 years and 0.1% thereafter. MAIN OUTCOMES AND MEASURES Annualized relapse rate (ARR), disability (Expanded Disability Status Scale score), change in anti-aquaporin 4 antibody, and safety of rituximab treatment. RESULTS Of 30 patients, 26 (87%) exhibited a marked reduction in ARR over 5 years (mean [SD] pretreatment vs posttreatment ARR, 2.4 [1.5] vs 0.3 [1.0]). Eighteen patients (60%) became relapse free after rituximab treatment. In 28 patients (93%), the disability was either improved or stabilized after rituximab treatment. No serious adverse events leading to discontinuation were observed during follow-up. CONCLUSIONS AND RELEVANCE Repeated treatment with rituximab in patients with NMOSD over a 5-period, using an individualized dosing schedule according to the frequency of reemerging CD27 + memory B cells, leads to a sustained clinical response with no new adverse events.

In central nervous system AQP4 autoimmunity, brain MRI abnormalities were more common than is generally appreciated and were characterized by their unique localization and configuration.