Shizuyo Tsujimura

Efficacy of rituximab (anti-CD20) for refractory systemic lupus erythematosus involving the central nervous system

Aim: Neuropsychiatric systemic lupus erythematosus (NPSLE) is a serious treatment-resistant phenotype of systemic lupus erythematosus. A standard treatment for NPSLE is not available. This report describes the clinical and laboratory tests of 10 patients with NPSLE before and after rituximab treatment, including changes in lymphocyte phenotypes. Methods: Rituximab was administered at different doses in 10 patients with refractory NPSLE, despite intensive treatment. Results: Treatment with rituximab resulted in rapid improvement of central nervous system-related manifestations, particularly acute confusional state. Rituximab also improved cognitive dysfunction, psychosis and seizure, and reduced the SLE Disease Activity Index Score at day 28 in all 10 patients. These effects lasted for >1 year in five patients. Flow cytometric analysis showed that rituximab down regulated CD40 and CD80 on B cells and CD40L, CD69 and inducible costimulator on CD4+ T cells. Conclusions: Rituximab rapidly improved refractory NPSLE, as evident by resolution of various clinical signs and symptoms and improvement of radiographic findings. The down regulation of functional molecules on B and T cells suggests that rituximab modulates the interaction of activated B and T cells through costimulatory molecules. These results warrant further analysis of rituximab as treatment for NPSLE.

Transcriptional regulation of multidrug resistance-1 gene by interleukin-2 in lymphocytes

P‐glycoprotein, encoded by the multidrug resistance (MDR)‐1 gene, expels various drugs from cells resulting in drug resistance. However, its functional relevance to lymphocytes and the regulatory mechanism remain unclear. Although MDR‐1 is known to be induced by various cytotoxic stimuli, it is poorly understood whether the activation stimuli such as cytokines induce MDR‐1 transcription. We investigated the transcriptional regulation of MDR‐1 in lymphocytes by activation stimuli, particularly by interleukin (IL)‐2. IL‐2 induced translocation of YB‐1, a specific transcriptional factor for MDR‐1, from the cytoplasm into nucleus of lymphocytes in a dose‐dependent manner and resulted in the sequential events; transcription of MDR‐1, expression of P‐glycoprotein on the cell surface, and excretion of the intracellular dexamethasone added in vitro. Transfection of YB‐1 anti‐sense oligonucleotides inhibited P‐glycoprotein expression induced by IL‐2. Cyclosporin A, a competitive inhibitor of P‐glycoprotein, recovered intracellular dexamethasone levels in lymphocytes. We provide the first evidence that IL‐2, a representative lymphocyte‐activation stimulus, induces YB‐1 activation followed by P‐glycoprotein expression in lymphocytes. Our findings imply that lymphocytes activation by IL‐2 in vivo, in the context of the pathogenesis of autoimmune diseases, results in P‐glycoprotein‐mediated multidrug resistance, and that P‐glycoprotein could be an important target for the treatment of refractory autoimmune diseases.

Tacrolimus, a Calcineurin Inhibitor, Overcomes Treatment Unresponsiveness Mediated by P-glycoprotein on Lymphocytes in Refractory Rheumatoid Arthritis

Objective. Tacrolimus, a calcineurin inhibitor, is used for treatment of rheumatoid arthritis (RA). It also inhibits functions of P-glycoprotein, which is involved in drug resistance. We examined the mechanisms of early response to 2-week tacrolimus treatment in patients with RA. Methods. One hundred thirteen patients with refractory RA despite at least 3 antirheumatic agents, including methotrexate, were treated with tacrolimus (1.5–3 mg/day) and the response was assessed at 2 weeks. Expression of the multidrug resistance (MDR-1) gene and P-glycoprotein was assessed in peripheral blood mononuclear cells (PBMC) collected from 113 patients and 40 healthy subjects. The drug exclusion function by the P-glycoprotein was measured by the residual amount of intracellular tritium-labeled dexamethasone cell/medium ratio (C/M ratio). Results. The disease activity of enrolled patients was 5.8 ± 1.2 (mean ± SD) by DAS28 erythrocyte sedimentation rate. A good response to tacrolimus was noted at 2 weeks in 22 of 113 patients. At baseline, PBMC of patients with RA showed upregulated expression of MDR-1 gene and P-glycoprotein and low C/M ratio. The response to tacrolimus correlated with P-glycoprotein expression and C/M ratio. A significant improvement in C/M ratio was noted after 2 weeks of treatment. The C/M ratio correlated significantly with P-glycoprotein expression on CD4+ lymphocytes. Conclusion. Early efficacy of tacrolimus treatment depended on its inhibitory effect on the drug exclusion function of P-glycoprotein, leading to restoration of intracellular therapeutic levels of corticosteroids and clinical improvement. Evaluation of P-glycoprotein expression on lymphocytes is potentially useful for predicting the response to RA treatment.

Treatment strategy based on targeting P-glycoprotein on peripheral lymphocytes in patients with systemic autoimmune disease

Although corticosteroids, immunosuppressants and disease-modifying antirheumatic drugs (DMARDs) are widely used in the treatment of various systemic autoimmune diseases such as systemic lupus erythematosus (SLE), we often experience patients with systemic autoimmune diseases who are resistant to these treatments. P-glycoprotein (P-gp) of membrane transporters, a product of the multiple drug resistance (MDR)-1 gene, is known to play a pivotal role in the acquisition of drug resistance to chemotherapy in malignancy. However, the relevance of MDR-1 and P-gp to resting and activated lymphocytes, which are the major target in the treatment of systemic autoimmune diseases, remains unclear. Studies from our laboratories found surface expression of P-gp on peripheral lymphocytes in patients with SLE and a significant correlation between the expression level and disease activity. Such expression is induced not only by genotoxic stresses but also by various stimuli including cytokines, resulting in active efflux of drugs from the cytoplasm of lymphocytes, resulting in drug-resistance and high disease activity. However, the use of both P-gp antagonists (e.g., cyclosporine) and inhibition of P-gp synthesis with intensive immunosuppressive therapy successfully reduces the efflux of corticosteroids from lymphocytes in vitro, suggesting that P-gp antagonists and P-gp synthesis inhibitors could be used to overcome drug-resistance in vivo and improve outcome. In conclusion, lymphocytes activated by various stimuli in patients with highly active disease apparently acquire MDR-1-mediated multidrug resistance against corticosteroids and probably some DMARDs, which are substrates of P-gp. Inhibition/reduction of P-gp could overcome such drug resistance. The expression of P-gp on lymphocytes is a promising marker of drug resistance and a suitable target to combat drug resistance in patients with active systemic autoimmune diseases.

Fragmented Hyaluronan Induces Transcriptional Up-regulation of the Multidrug Resistance-1 Gene in CD4+ T Cells

P-glycoprotein, encoded by the multidrug resistance (MDR)-1 gene, expels various drugs from cells resulting in multidrug resistance. We found previously that interleukin-2, a lymphocyte-activation cytokine, induces P-glycoprotein expression on lymphocytes. Lymphocyte activation involves adhesion with the extracellular matrix, such as hyaluronan, through adhesion molecules on lymphocytes. We investigated the transcriptional regulation of MDR-1 in lymphocytes by fragmented hyaluronan. Fragmented hyaluronan (especially the 6.9-kDa form), not native high molecular hyaluronan, induced translocation of YB-1, a specific transcriptional factor for MDR-1, from the cytoplasm into the nucleus and resulted in the transcription of MDR-1 and the expression of P-glycoprotein on lymphocytes in a dose-dependent manner. Transfection of YB-1 antisense oligonucleotides inhibited P-glycoprotein expression induced by fragmented hyaluronan. The fragmented hyaluronan induced significant P-glycoprotein expression on only activated CD4+ T cells, which highly expressed CD69, and resulted in excretion of intracellular dexamethasone added in vitro. Cyclosporin A, a competitive P-glycoprotein inhibitor, restored intracellular dexamethasone levels in CD4+ T cells. Anti-CD44 monoclonal antibody (Hermes-1) inhibited fragmented hyaluronan-induced YB-1 activation and P-glycoprotein expression in CD4+ T cells. We provide the first evidence that binding of fragmented hyaluronan to CD44 induces YB-1 activation followed by P-glycoprotein expression in accordance with activation of CD4+ T cells. Our findings imply that CD4+ T cell activation by fragmented hyaluronan, induced by characteristic extracellular matrix changes in inflammation, tumors, and other conditions, results in P-glycoprotein-mediated multidrug resistance.

Efficacy of mizoribine treatment in patients with SjÖgren’s syndrome: an open pilot trial

Abstract The aim of this study was to evaluate the efficacy and safety of mizoribine in patients with Sjögren’s syndrome. Forty patients with sicca syndrome, whose conditions were definitely diagnosed as Sjögren’s syndrome, were given mizoribine orally at a dosage of 150 mg/day for 12 months. The percentage change in salivary secretion after 3, 6, and 12 months of the therapy increased to +112.2% (P < 0.001), +119.9% (P < 0.01), and +147.3% (P < 0.001), respectively, compared with the baseline. Serum IgG levels decreased significantly throughout the study, and the level was 1969.4 ± 620.0 mg/dl after treatment for 12 months compared with the pretreatment value of 2094.3 ± 746.6 mg/dl (P < 0.05). The patient’s assessment of clinical signs and symptoms on a 10-cm visual analog scale improved significantly from 7.2 ± 2.3 cm at the start of the treatment to 5.0 ± 1.9 cm after 12 months (P < 0.001). There was a similar improvement in the physician’s assessment using the 10-cm visual analog scale: 7.1 ± 1.6 cm at the start of the treatment and 5.2 ± 1.9 cm after 12 months (P < 0.001). With regard to safety, no serious adverse reactions were observed. Although a controlled study would be required to clarify the efficacy of mizoribine, these preliminary observations indicate its efficacy for ameliorating glandular symptoms through improvements in immune abnormalities in patients with Sjögren’s syndrome.

Disease control by regulation of P-glycoprotein on lymphocytes in patients with rheumatoid arthritis

The main purpose of treatment of rheumatoid arthritis (RA) with disease modifying antirheumatic drugs (DMARDs) is to control activation of lymphocytes, although some patients do not respond adequately to such treatment. Among various mechanisms of multidrug resistance, P-glycoprotein (P-gp), a member of ATP-binding cassette transporters, causes drug-resistance by efflux of intracellular drugs. Certain stimuli, such as tumor necrosis factor-α, activate lymphocytes and induce P-gp expression on lymphocytes, as evident in active RA. Studies from our laboratories showed spontaneous nuclear accumulation of human Y-box-binding protein-1, a multidrug resistance 1 transcription factor, in unstimulated lymphocytes, and surface overexpression of P-gp on peripheral lymphocytes of RA patients with high disease activity. The significant correlation between P-gp expression level and RA disease activity is associated with active efflux of drugs from the lymphocyte cytoplasm and in drug-resistance. However, the use of biological agents that reduce P-gp expression as well as P-gp antagonists (e.g., cyclosporine) can successfully reduce the efflux of corticosteroids from lymphocytes in vitro, suggesting that both types of drugs can be used to overcome drug-resistance and improve clinical outcome. We conclude that lymphocytes activated by various stimuli in RA patients with highly active disease acquire P-gp-mediated multidrug resistance against corticosteroids and probably some DMARDs, which are substrates of P-gp. Inhibition/reduction of P-gp could overcome such drug resistance. Expression of P-gp on lymphocytes is a promising marker of drug resistance and a suitable therapeutic target to prevent drug resistance in patients with active RA.

Bolus infusion of human urinary trypsin inhibitor improves intractable interstitial pneumonia in patients with connective tissue diseases

OBJECTIVE Interstitial pneumonia (IP) associated with CTDs often progresses despite conventional immunosuppressive treatment. We investigated the efficacy of human urinary trypsin (UT) inhibitor (ulinastatin) on refractory IP. METHODS Five patients with IP received UT inhibitor (3 x 10(5) U) infusion into the internal jugular vein, three times in a single day. The response to this therapy was assessed clinically and by chest CT, PaO(2) and serum KL-6. The kinetics of UT inhibitor was determined in arterial blood. We measured serum levels of monocyte chemotactic protein-1 and TGF-beta1, which are thought to be involved in the pathogenesis of IP. RESULTS Serum concentrations of UT inhibitor increased immediately to >150 U/ml after infusion of 3 x 10(5) U of UT inhibitor. The treatment resulted in clinical and radiological improvements in four patients, and allowed reduction of oxygen therapy following improvement of hypoxaemia within 1 month. UT inhibitor decreased serum levels of KL-6 in all patients and had no adverse effects. MCP-1 and TGF-beta1 concentrations were higher in the patients than in normal subjects, and infusion of 3 x 10(5) U of UT reduced the concentrations within 3 h of infusion. CONCLUSION UT inhibitor bolus infusion therapy is a potentially useful therapeutic strategy for intractable IP based on the different mechanism of action relative to conventional immunosuppressive therapy and lack of serious treatment-related adverse effects.

Relevance of P-glycoprotein on CXCR4+ B cells to organ manifestation in highly active rheumatoid arthritis

Abstract Introduction: In rheumatoid arthritis (RA), P-glycoprotein (P-gp) expression on activated B cells is associated with active efflux of intracellular drugs, resulting in drug resistance. CXCR4 is associated with migration of B cells. This study was designed to elucidate the relevance of P-gp expression on CXCR4+ B cells to clinical manifestations in refractory RA. Methods: CD19+ B cells were analyzed using flow cytometry and immunohistochemistry. Results: P-gp was highly expressed especially on CXCR4+CD19+ B cells in RA. The proportion of P-gp-expressing CXCR4+ B cells correlated with disease activity, estimated by Simplified Disease Activity Index (SDAI), and showed marked expansion in RA patients with high SDAI and extra-articular involvement. In highly active RA, massive infiltration of P-gp+CXCR4+CD19+ B cells was noted in CXCL12-expressing inflammatory lesions of RA synovitis and RA-associated interstitial pneumonitis. In RA patient with active extra-articular involvement, intracellular dexamethasone level (IDL) in lymphocytes diminished with expansion of P-gp+CXCR4+ CD19+ B cells. Adalimumab reduced P-gp+CXCR4+ CD19+ B cells, increased IDL in lymphocytes, and improved the clinical manifestation and allowed tapering of concomitant medications. Conclusions: Expansion of P-gp+CXCR4+ B cells seems to be associated with drug resistance, disease activity and progressive destructive arthritis with extra-articular involvement in RA.

Role of P-glycoprotein on CD69+CD4+ cells in the pathogenesis of proliferative lupus nephritis and non-responsiveness to immunosuppressive therapy

Introduction P-glycoprotein (P-gp) expression on activated lymphocytes in systemic lupus erythematosus (SLE) plays a role in active efflux of intracellular drugs, resulting in drug resistance. The role of P-gp-expressing lymphocytes in the pathogenesis of SLE remains unclear. The aim of this study was to determine the importance of P-gp+CD4+ cells in organ manifestations in refractory SLE. Methods The proportion of P-gp+CD4+ cells was determined by flow cytometry in peripheral blood of patients with SLE (n=116) and healthy adults (n=10). Renal biopsy specimens were examined by immunohistochemistry for P-gp expression. Results CD69 is a marker of CD4 cell activation. The proportion of both P-gp-expressing CD4+ cells and CD69-expressing CD4+ cells in peripheral blood was higher in SLE than control. The proportion of P-gp+CD69+CD4+ cells correlated with Systemic Lupus Erythematosus Disease Activity Index and was higher in poor responders to corticosteroids. Furthermore, the proportion of P-gp+CD69+CD4+ cells was significantly higher in proliferative lupus nephritis (LN) with poor response to corticosteroids. The efficacy of immunosuppressive therapy depended on the regulation of the proportion of P-gp+CD69+CD4+ cells. Marked accumulation of P-gp+CD4+ cells in renal interstitial tissue and high proportion of peripheral P-gp+CD69+CD4+ cells were noted in patients with proliferative LN. Conclusions The results showed high proportion of P-gp+CD69+CD4+ cells in peripheral blood and their accumulation in renal tissue in patients with proliferative LN refractory to CS therapy, suggesting that P-gp expression on activated CD4+ T cells is a potentially useful marker for refractoriness to treatment and a novel target for treatment.