Shingo Nakayamada

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.

Discontinuation of adalimumab after achieving remission in patients with established rheumatoid arthritis: 1-year outcome of the HONOR study

Objectives To investigate the possibility of discontinuing adalimumab (ADA) for 1 year without flaring (DAS28-erythrocyte sedimentation rate (ESR) ≥3.2), and to identify factors enabling established patients with rheumatoid arthritis (RA) to remain ADA-free. Methods Of 197 RA patients treated with ADA+methotrexate (MTX), 75 patients who met the ADA-free criteria (steroid-free and sustained DAS28-ESR remission for 6 months with stable MTX doses) were studied for 1 year. Results The mean disease duration and DAS28-ESR score in 75 patients was 7.5 years and 5.1 at baseline, respectively. The proportion of patients who sustained DAS28-ESR <2.6 (48%) and DAS28-ESR <3.2 (62%) for 1 year were significantly lower in the ADA discontinuation group than in the ADA continuation group; however, in patients with deep remission (DAS28-ESR ≤1.98) identified by receiver operating characteristics analysis following logistic analysis, these rates increased to 68% and 79%, respectively, with no significant difference between both groups. Remarkably, ADA readministration to patients with flare was effective in returning DAS28-ESR to <3.2 within 6 months in 90% and 9 months in 100% patients; among the patients who sustained DAS28-ESR <3.2 during ADA discontinuation, 100% remained in structural remission and 94% in functional remission. Conclusions The possibility of remaining ADA-free for 1 year was demonstrated in established patients with RA with outcomes that ADA can be discontinued without flaring in 79% patients with deep remission, with similar rates in the ADA continuation group, and showed no functional or structural damage in patients with DAS28-ESR <3.2. ADA readministration to patients with flare during ADA discontinuation was effective.

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.

Alendronate Protects Premenopausal Women from Bone Loss and Fracture Associated with High-dose Glucocorticoid Therapy

Objective We assessed the efficacy of bisphosphonate in premenopausal women (n = 47) commencing high-dose glucocorticoid (GC) therapy in protection against induced bone loss and bone fracture. Methods Subjects had just developed systemic autoimmune diseases and were randomized to be treated with 1 mg/kg/day prednisolone and alfacalcidol 1 μg/day alone (alfacalcidol group; n = 22), or prednisolone and alfacalcidol 1 μg/day with alendronate 5 mg/day (alendronate group; n = 25), each for 18 months. Results The percentage changes in lumbar spine bone mineral density (BMD) after 6 months of the therapy were −10.5% ± 0.8% in the alfacalcidol group, but only −2.1% ± 1.2% in the combined group. The rate of bone loss in the lumbar spine was significantly lower in the combined group than in the alfacalcidol group at 6 months. At 12 months of treatment, the percentage change in lumbar spine BMD was increased by 1.7% ± 1.4% in the combined group, but decreased by 9.9% ± 1.9% in the alfacalcidol group; the difference was significant. Bone fracture occurred at 12 months or later in 4 patients of the alfacalcidol groups, but not in the combined group, even at up to 18 months. Conclusion Our results indicate that alendronate with alfacalcidol can maintain BMD and protects against high-dose GC-induced bone loss and bone fracture.

Mast cell–derived tryptase inhibits apoptosis of human rheumatoid synovial fibroblasts via rho‐mediated signaling

OBJECTIVE An abundance of mast cells are found in the synovium of patients with rheumatoid arthritis (RA). However, the role of mast cells in the pathogenesis of RA remains unclear. This study was undertaken to elucidate a role for mast cells in RA by investigating the antiapoptotic effects of tryptase, a major product of mast cells, on RA synovial fibroblasts (RASFs). METHODS RA synovial tissue was obtained from RA patients during joint replacement surgery, and histologic changes in the tissue were examined. The expression of cell surface molecules and apoptotic markers on RASFs were detected by flow cytometry. Rho activation was determined using a pull-down assay. RESULTS Mast cells, bearing both c-Kit and tryptase, accumulated in the sublining area of proliferating synovial tissue from RA patients. Protease-activated receptor 2 (PAR-2), a receptor for tryptase, was expressed on RASFs in the lining area, close to tryptase-positive mast cells in the RA synovium. Fas-mediated apoptosis of RASFs was significantly inhibited, in a dose-dependent manner, by the addition of tryptase, and this effect correlated with increased activation of Rho kinase. Furthermore, Y27632, a Rho kinase inhibitor, reduced the antiapoptotic effect of tryptase on RASFs, suggesting that Rho was responsible for the antiapoptotic effects of tryptase. CONCLUSION These results demonstrate that tryptase has a strong antiapoptotic effect on RASFs through the activation of Rho. Thus, we propose that the release of tryptase by mast cells leads to the binding of tryptase to PAR-2 on RASFs and inhibits the apoptosis of RASFs via the activation of Rho. Such mechanisms could play a pivotal role in the marked proliferation of RASFs and hyperplasia of synovial tissue seen in RA synovium.

Leflunomide inhibits PDK1/Akt pathway and induces apoptosis of human mast cells.

Mast cells release many inflammatory mediators that play an important role not only in allergic diseases but also in chronic inflammatory diseases, autoimmune diseases, and others. A lot of mast cells exist in synovium of rheumatoid arthritis, and it is known that synovitis does not occur in mast cell-deficient mice. Thus, it is thought that mast cells play a very important role in rheumatoid arthritis pathogenesis. Leflunomide is a drug used clinically in the treatment of rheumatoid arthritis. We used clinical doses of 2-cyano-3-hydroxy-N-(4-trifluoromethylphenyl)-butenamide (A77 1726), which is an active metabolite of leflunomide, and decreased the number of viable human primary mast cells in a concentration-dependent manner. This decrease was not reversed by uridine. Inhibition of pyrimidine synthesis by dihydro-orotic acid dehydrogenase inhibition, which is the primary mechanism of action of A77 1726, was not involved. A77 1726 dramatically induced apoptosis of human mast cells and inhibited the phosphorylation of Akt, an important survival signal of mast cells, in a concentration-dependent manner. Caspases 3 and 9, downstream molecules of Akt survival pathway, were also fragmented by A77 1726. In addition, it became evident for the first time that the mechanism involved in this result was the concentration-dependent inhibition of PDK1 phosphorylation, which controls the activation of Akt. These results indicate a new way of controlling mast cells and may therefore be the basis for innovative approaches to the treatment of various diseases related to mast cells.

Brief report: Takayasu arteritis and ulcerative colitis: High rate of co-occurrence and genetic overlap

Takayasu arteritis (TAK) is a systemic vasculitis affecting large arteries and large branches of the aorta. Ulcerative colitis (UC) is a prevalent autoimmune colitis. Since TAK and UC share HLA–B*52:01 and IL12B as genetic determinants, and since there are case reports of the co‐occurrence of these diseases, we hypothesized that UC is a common complication of TAK. We undertook this study to perform a large‐scale analysis of TAK, both to evaluate the prevalence of concurrent cases of TAK and UC and to identify and estimate susceptibility genes shared between the 2 diseases.

Activation of Syk in peripheral blood B cells in patients with rheumatoid arthritis: a potential target for abatacept therapy.

B cells play a pivotal role in the pathogenesis of autoimmune diseases. Although Syk functions as a key molecule in B cell receptor signaling, the pathologic role of Syk in B cells in rheumatoid arthritis (RA) remains unclear. The purpose of this study was to assess the relevance of activation of Syk in B cells to the pathologic development of RA and to the responsiveness of RA patients to treatment with biologics.

Study on the safety and efficacy of tocilizumab, an anti-IL-6 receptor antibody, in patients with rheumatoid arthritis complicated with AA amyloidosis

Abstract Objectives: Although treatment of rheumatoid arthritis (RA) has progressed by the use of biologics, amyloid A (AA) amyloidosis is still an intractable complication in patients with RA. In the present study, safety and efficacy of 1-year treatment with an anti-IL-6 receptor antibody tocilizumab (TCZ) on RA and AA amyloidosis were estimated. Methods: TCZ (8 mg/kg every 4 weeks) was administered to five RA patients complicated with AA amyloidosis. The primary end point was improvement in renal dysfunction and the secondary end point was CDAI at 1 year after the treatment. Results: An improvement in the renal dysfunction, including urinary protein secretion, was found, in four patients including two patients who were refractory to etanercept, with a remarkable decrease of SAA concentration, and the progression of organ dysfunction was prevented at 1 year in all patients treated with TCZ. The mean clinical disease activity index decreased from 33.9 to 4.7 (p = 0.012) in five patients treated with TCZ for 1 year. Three non-serious adverse events were observed in two patients. Conclusions: TCZ ameliorates renal dysfunction in RA patients complicated with AA amyloidosis who are refractory to conventional therapies, thereby suggesting that TCZ has a potential to regulate AA amyloidosis.