Expression of many virulence factors in P. aeruginosa is regulated by a cell density dependent mechanism called quorum sensing. Quorum sensing allows P. aeruginosa to sense the density of the surrounding bacterial population and to coordinately regulate transcription of various virulence genes. Pseucomonas aeruginosa is a common pathogen infecting chronic respiratory infections, such as diffuse panbronchiolitis (DPB) patients. Although these patients are typically treated with multiple anti-pseudomonal antibiotics, the infection is rarely eradicated and often results in mortality. In the 1980s it was reported that long-term therapy with low doses of erythromycin improved the clinical symptoms of DPB patients colonized with P. qeruginosa. Recently it has been demonstrated that sub MIC concentrations of macrolides strongly inhibite Pseudomonas quorum sensing system. These data suggested a novel mechanism of quorum sensing regulation of antibiotic sensitivity.

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Crohn’s disease and ulcerative colitis are two major forms of human inflammatory bowel diseases (IBD). Their etiology is unknown, but increasing evidence indicate that immune mechanisms play an important role. It is well known that immune responses in the intestine remain in a state of controlled inflammation, suggesting that not only active suppression by regulatory T (T_R) cells plays an important role in the normal intestinal homeostasis, but also its dysregulation leads to the development of IBD. This article reviews the unique aspects of T_R cells and discuss how these control the intestinal homeostasis.

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Memory B cells, which carry immunoglobulin somatic hypermutations, generate immunoglobulins rapidly and vigorously in the secondary immune response. We recently highlighted studies confirming that CD27 surface antigen is a memory B-cell marker. By using the memory B-cell marker, peripheral blood B cells were clearly distinguished into naive and memory B cells. The B cells are further separated to three populations by the expressions of CD27 and IgD: IgD⁺CD27^- naive B cells (circulating B cell 1:cB1), IgD⁺CD27⁺ unclass-switched memory B cells (cB2, so-called IgM memory B cells) and IgD^-CD27⁺ class-switched memory B cells (cB3, switched memory B cells). Here we show molecules which are involved in characteristics of naive/memory B cells and their functions. This functionally distinct B cell subset and molecules involved in the subset may represent an important mechanism by which quiescent human B cells can initiate and propagate rapid and vigorous immune memory responses, and regulate the synthesis of low/high affinity antibodies.

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It has been suggested that oxidative stress participates in the pathogenesis of hepatitis C virus infection. It also has been made clear that redox status in T cell and macrophage relates to the activity of virus infectious disease such as HIV infection. With such background we evaluated the relationship between the intracellular redox status of T cell and macrophage and the activity of HCV positive chronic liver disease. Intracellular GSH and GSSG levels of T cell and macrophage were determined in twenty-five HCV positive asymptomatic carriers (C-ASC), sixty-three chronic hepatitis patients (C-CH), ten HCV positive liver cirrhosis patients (C-LC) and twenty-nine healthy controls. The intracellular GSH levels of T cell (T-GSH) significantly decreased in both C-CH and C-LC compared with healthy controls. No significant differences in the T-GSH levels were found between healthy controls and C-ASC. T-GSH levels of C-CH and C-LC were significantly lower compared with C-ASC. The intracellular GSH levels of macrophage (CD14-GSH) of C-LC were significantly decreased compared with healthy controls. The CD-14-GSH levels of C-CH and C-LC were significantly lower compared with C-ASC. There was no correlation between intracellular GSH, GSSG levels and the serum levels of iron-related markers, fibrogenesis markers and other clinical parameters. These results suggest that the intracellular redox status of T cell and macrophage relates to the progression of HCV related chronic liver disease.

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The studies using an immunohistological technique revealed that overexpression of oxidative stress-related substance such as HNE was observed in the liver of primary biliary cirrhosis patients. These data suggested that oxidative stress participated in the pathogenesis of primary biliary cirrhosis. Therefore we analyzed serum oxdative stress marker (8-OHdG) and anti oxidative substances (Mn-SOD and TRX) to evaluate their clinical significance. In addition we analyzed the genotype of anti oxidative substance GST that has been reported to relate susceptibility of autoimmune disease. Serum levels of 8-OHdG, Mn-SOD and TRX in PBC patients were significantly higher than those of healthy subjects (P<0.001). Though there was no relation between serum level of 8-OHdG and clinical data, positive correlation between serum level of Mn-SOD, TRX and serum level of ALP, IgM was observed. Positive correlation was also observed between serum level of Mn-SOD and TRX. Serum levels of Mn-SOD of patients who responded to UDCA therapy were significantly higher than those of patients who did not response to therapy (P<0.01). Although genotypic difference of GSTM1 and GSTT1 by peripheral blood mononuclear cells did not relate to susceptibility of PBC, serum titer of AMA of GSTM1 null and GSTT1 null patients were significantly higher than those of GSTM1 positive and/or GSTT1 positive patients (P<0.05). These findings suggest that serum oxidative stress-related markers may reflect the extent of liver damage of PBC, and may relate to the efficacy of UDCA therapy on PBC. It also made clear that genotype of GST related to the titer of AMA.

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To evaluate the efficacy and safety of cevimeline hydrochloride for the treatment of dry mouth in patients with Sjögren’s syndrome (SS), eight SS patients received 30 mg of cevimeline twice or three times daily for 24 weeks. Six out of the eight patients had improvement in dry mouth. Five patients had more than 20% increase in saliva secretion. In the assessment of salivary gland scintigraphy, three patients showed improvement. There was a significant negative correlation between the improvement of saliva secretion and the severity of tissue damage assessed by MR sialography (r=−0.754, p<0.05). One patient stopped cevimeline at 4 weeks because of headache and nausea. There was no significant change in laboratory data. Cevimeline is safe and effective medicine for dry mouth in patients with SS, in particular, with less severe salivary gland destruction.

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A 18-year-old female had low grade fever, butterfly rush, proteinuria, leukocytopenia and hypocomplimentemia in 1988, and she was diagnosed as systemic lupus erythematosus (SLE) with lupus nephritis (WHOIIb). Treatments with prednisolone and mizoribine resulted in the remission for three years. In May 2001, she presented neurosis and polakisuria despite of the increase of prednisolone to 20 mg/day. Finally, she admitted in our hospital because of manic and repressive state and disorientaion. A brain MRI revealed high intensity lesions in bilateral basal ganglia in T2 weighted images, and cerebrospinal fluid showed elevated protein and IFN-α (421 IU/ml). In addition, she manifested neurogenic bladder, muscle weakness and hyperactive deep tendon reflex of bilateral lower limbs due to both supranuclear disorder and hypesthesia under the Th 10 level. Spinal MRI revealed marked atrophy and high intensity signals at the middle to lower thoracic spinal cord in T2 weighted images, indicating complication of lupus myelitis as well as cerebral involvement. Although the symptoms of CNS lupus did not respond to prednisolone, twelve monthly cyclophosphamide pulse therapy (IV-CY) has resolved urinary disturbance, muscle weakness and sensory loss, along with the improvement of both cerebral and spinal MRI images. Lupus myelitis and neurogenic bladder are the rare, but very refractory manifestation among CNS involvement of SLE. We here propose IV-CY as an invaluable choice for the treatment of not only active lupus myelitis but also neurogenic bladder resisted for steroid.

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A 52 year-old woman noticed general fatigue, polyarthralgia, and muscle weakness of lower extremities in October 2001. In December, she felt difficulty in walking due to muscle weakness. In January 2002, she admitted another hospital because of dyspnea on exertion and edema of lower extremities. Laboratory test revealed leukocytopenia, the elevation of creatine kinase and positive anti-U1-RNP antibodies. Her chest computed tomography (CT) showed severe interstitial pneumonia. Cardiac echogram revealed that she had pericardial effusion and pulmonary hypertension. Then she was transferred to Keio University Hospital and she was diagnosed as having mixed connective tissue disease (MCTD) manifestating myositis, interstitial pneumonia, pulmonary hypertension and pericarditis. Prednisolone (PSL) 60mg daily following to methylprednisolone (mPSL) pulse therapy was begun and her symptoms were gradually improved. In middle of February, she complained of high fever over 39.0°C. Bacterial culture tests were negative and laboratory data indicated pancytopenia and a high level of serum ferritin. Bone marrow aspiration revealed hemophagocytosis in bone marrow specimens and she was diagnosed as having hemophagocytic syndrome associated with MCTD. mPSL pulse therapy was not effective and intermittent cyclophosphamide pulse therapy (IV-CY) was performed resulting in improvement of the symptoms. This case suggested the effectiveness of IV-CY therapy in patients with corticosteroid-resistant HPS associated with connective tissue diseases.

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A 11-year-old female admitted to our hospital because of erythema of the face and the trunk, and a wide and dense cluster of verruca vulgaris on the right sole. She had no family history of immunodeflciency, no perinatal abnormality, no growth abnormality, or no history of severe infections. From the age of 4 years, she noticed erythema around her nose. At the age of 9 years, small erythema and papules appeared on her chest. In January, 2003, erythema around her nose and papules of the trunk spread rapidly, and she also felt fatigue and effort dyspnea. Laboratory examinations revealed near absence of serum IgG, and IgE, high serum IgM (525 mg/dl), and normal IgA and IgD. Th1/Th2 ratio was 36.9. We diagnosed her as having hyper-IgM syndrome. Histological examinations of a skin biopsy showed the inflltration composed of mainly histiocytes, and mildly atypical CD8+ T cells around the blood vessels in the dermis. We concluded her skin manifestations as reactive lymphohistiocytic inflltration at the base of immunodeflciency and durable stimulation of various antigens. Her skin manifestations improved transiently by the intravenous immunogrobulin and corticosteroids therapy.

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