Incidence and risk factors for reactivation from resolved hepatitis B virus in rheumatoid arthritis patients treated with biological disease-modifying antirheumatic drugs.

AIM: To identify the incidence and risk factors for hepatitis B virus (HBV) reactivation in rheumatoid arthritis (RA) patients with resolved HBV receiving biological disease-modifying antirheumatic drugs (bDMARDs). METHOD: Rheumatoid arthritis patients in whom bDMARD therapy was initiated in our departments from April 2009 to July 2016 were reviewed. The patients diagnosed with resolved HBV and whose HBV-DNA levels had been repeatedly measured were enrolled. The endpoint was HBV reactivation (a positive conversion of HBV-DNA or unquantifiable cases with positivity <20 IU/mL). Nucleic acid analogues (NAAs) were administered when the HBV-DNA levels increased beyond 20 IU/mL. The associations between HBV reactivation and the clinical findings were retrospectively analyzed. RESULTS: One hundred and fifty-two RA patients with resolved HBV were enrolled; 133 (88%) patients had antibodies against HBV surface antigen (anti-HBs). The medicines that were administered included: abatacept (n = 29), golimumab (n = 26), etanercept (n = 25), tocilizumab (n = 25), adalimumab (n = 19), infliximab (n = 17) and certolizumab pegol (n = 11). During the observation period (15 [interquartile range 4.0-34] months), 7 (4.6%) patients developed HBV reactivation. In 5 of these patients, the HBV-DNA levels became negative or remained at <20 IU/mL (+) without NAA therapy. HBV-DNA levels of >20 IU/mL were observed in 2 patients but the HBV-DNA levels became negative after NAA treatment. Patients who were negative for anti-HBs showed a significantly higher incidence of HBV reactivation (P = 0.013). CONCLUSION: HBV reactivation occurred in 4.6% of RA patients with resolved HBV during the treatment with bDMARDs and the absence of anti-HBs may be a risk factor for the reactivation of resolved HBV.

Comparison of efficacy of TNF inhibitors and abatacept in patients with rheumatoid arthritis; Adjusted with propensity score matching.

The aim of this study was to compare the clinical outcome of patients with rheumatoid arthritis seen in routine clinical practice treated with either TNF inhibitors or abatacept. To overcome potential bias, both propensity score matching and Inverse Probability of Treatment Weighting were used for patient selection. The propensity score matching procedure selected 315 matched pairs of patients who were treated with TNF inhibitors or abatacept. At week 52, SDAI in TNF inhibitors was lower than abatacept. In contrast, analysis of biologics-naive patients using the propensity-score matching (n = 150; in each group) showed comparable clinical efficacy. Consistent results were obtained by the use of Inverse Probability of Treatment Weighting (581 patients treated with TNF inhibitors and 353 patients treated with abatacept). The predictors of response to each treatment were different; abatacept appeared to benefit patients with high baseline RF titers while TNF inhibitors appeared to benefit patients with low baseline HAQ-DI.

Clinical, radiographic and functional efficacy of abatacept in routine care for rheumatoid arthritis patients: Abatacept Leading Trial for RA on Imaging Remission (ALTAIR) study.

OBJECTIVES: To investigate the efficacy and safety of abatacept for treating patients with rheumatoid arthritis (RA) in routine clinical practice and to determine the prognostic factors affecting clinical outcomes. METHODS: We performed a retrospective study of 194 RA patients treated with abatacept. Clinical outcomes at 1 year after the treatment were assessed. Joint damage was assessed by the van der Heijde-modified total Sharp score (mTSS). RESULTS: Of the 194 patients, abatacept was discontinued in 51 patients, resulting in a retention rate at week 52 of 73.7%. At week 52, 23.7% of patients achieved clinical remission (SDAI ≤3.3). Lower SDAI and higher RF titre at baseline were the prognostic factor for SDAI at 52 weeks. Structural remission (ΔmTSS ≤0.5) was achieved in 73.4% of patients. However, clinical relevant radiographic progression which was defined as an increase in ΔmTSS >3 in a year, occurred in 7.6% of patients. Likewise, rapid radiological progression, which was defined as an increase in ΔmTSS >5 in a year, was observed in 6.4% of patients. 16.5% of patients achieved comprehensive disease remission, which was defined as SDAI ≤3.3, HAQ-DI ≤0.5, ΔmTSS ≤0.5, while 22.4% of patients achieved comprehensive disease control (CDC), which was defined as SDAI ≤11.0, HAQ-DI ≤0.5, ΔmTSS ≤0.5. CONCLUSIONS: The present results confirm that abatacept is effective and safe in routine clinical practice. It is possible that abatacept is more effective in seropositive RA patients with significant immunological abnormality.

Association of the multi-biomarker disease activity score with joint destruction in patients with rheumatoid arthritis receiving tumor necrosis factor-alpha inhibitor treatment in clinical practice.

OBJECTIVE: Evaluate the association between the multi-biomarker disease activity (MBDA) score and radiographic progression in patients with rheumatoid arthritis (RA) treated with tumor necrosis factor (TNF)-α inhibitors. METHODS: Change (Δ) in modified total Sharp score (mTSS) over 52 weeks and disease activity scores were examined retrospectively by Spearman's rank correlation coefficient in patients (N = 83) with RA initiating TNF-inhibitor treatment. Relative risk (RR) of ΔmTSS >0.5 for low MBDA score and 28-joint count disease activity score (DAS28) categories and associations between ΔmTSS and MBDA score categories conditional on DAS28 categories were assessed. RESULTS: At 52 weeks, 34% of patients had ΔmTSS >0.5 and 12% had ΔmTSS >3. Strongest correlations were observed between ΔmTSS and MBDA score (r = 0.47) or DAS28 (r = 0.42) at Week 24 and for area under the curve at Week 52 (MBDA score: r = 0.44, DAS28: r = 0.41), all p < 0.001. At Week 24, RR of ΔmTSS >0.5 for moderate/high MBDA score (≥30) or DAS28 (>3.2) were 6.6 (p < 0.001) and 2.7 (p = 0.005), respectively. Low DAS28 had greater risk of ΔmTSS >0.5 at 52 weeks when MBDA score was ≥30 (p < 0.05). CONCLUSION: Higher MBDA score or DAS28 at Week 24 was associated with greater radiographic progression over 52 weeks of TNF-inhibitor treatment. MBDA score improved risk discrimination for radiographic progression within DAS28 categories.

Histamine inhibits differentiation of skin fibroblasts into myofibroblasts.

Histamine and TGF-ß, major mediators secreted by mast cells, are involved in skin inflammation and play critical roles in the pathogenesis of systemic sclerosis. However, the roles of signaling mechanisms in the development of skin fibrosis remain largely unclear. Here we show that histamine suppressed the expression of α smooth muscle actin (αSMA), a marker of myofibroblasts, induced by TGF-ß1 in skin fibroblasts. Histamine H1-receptor (H1R), but not H2-receptor (H2R) or H4-receptor (H4R), was expressed on skin fibroblasts at both mRNA and protein levels. Interestingly, an H1R antagonist, but not H2R or H4R antagonists, antagonized the histamine-mediated suppression of αSMA expression by TGF-ß1. Correspondingly, phosphorylated Smad2 was detected after treatment with TGF-ß1, whereas the addition of histamine inhibited this phosphorylation. Taken together, histamine-H1R decreased TGF-ß1-mediated Smad2 phosphorylation and inhibited differentiation of skin fibroblasts into myofibroblasts.

Low complements and high titre of anti-Sm antibody as predictors of histopathologically proven silent lupus nephritis without abnormal urinalysis in patients with systemic lupus erythematosus.

OBJECTIVE: The aim of this study was to clarify the clinical characteristics and predictors of silent LN (SLN), a type of LN in SLE without abnormal urinalysis or renal impairment. METHODS: Of 182 patients who underwent renal biopsy, 48 did not present with abnormal urinalysis or renal impairment at the time of biopsy. The patients with LN (SLN group, n = 36) and those without LN (non-LN group, n = 12) were compared with respect to their baseline characteristics. Bivariate analysis comprised Fisher's exact test and the Mann-Whitney test, whereas multivariate analysis employed binomial logistic regression analysis. RESULTS: LN was histopathologically identified in 36 of 48 patients. According to the International Society of Nephrology/Renal Pathology Society classification, 72% of the SLN patients were classified as having class I/II, with a further 17% having class III/IV. Bivariate analyses indicated that platelet count, serum albumin, complement components (C3 and C4), complement haemolytic activity (CH50), anti-Sm antibody titre and anti-ribonucleoprotein antibody titre were significantly different between groups. Multivariate analysis indicated that CH50 and C3 titres were significantly lower in the SLN group, whereas anti-Sm antibody titre was significantly higher. The cut-off titre, calculated based on the receiver operating characteristic curve for CH50, was 33 U/ml, with a sensitivity and specificity of 89% and 83%, respectively. The cut-off titre for anti-Sm antibodies was 9 U/ml, with a sensitivity and specificity of 74% and 83%, respectively. CONCLUSION: Low titres of CH50 and C3 and a high titre of anti-Sm antibody were identified as predictors of SLN.

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.

Efficacy and safety of reducing duration of infliximab infusion.

OBJECTIVE: To evaluate the safety and efficacy of reducing the duration of infliximab infusion for rheumatoid arthritis (RA) treatment. METHODS: The first 6 infliximab infusions were each administered over a 2-h period. If no adverse reaction was observed, infusion times were shortened to 1 h starting with the seventh infusion with further shortening to 30 min starting with the thirteenth infusion. Subjects were divided into two groups: shortened infusion time group, in which infusion times were shortened as above; and constant infusion time group, in which infusion time was 2 h. Incidence of infusion reactions and improvement in disease activity score for 28 joints (DAS-28) erythrocyte sedimentation rate (ESR) for total infusions were compared for the seventh to twelfth and thirteenth to eighteenth infusions. RESULTS: The incidences of infusion reactions after the seventh to twelfth and thirteenth to eighteenth infusions in the shortened infusion time group were 0.53% and 0.58%, respectively. In the constant infusion time group, these were 0.70% and 0.67%, respectively. Furthermore, shortening the infusion duration did not affect the DAS-28 (ESR) improvement rate. CONCLUSIONS: We established that this stage-wise shortening of infusion duration, first to 1 h and then to 30 min, did not compromise the safety or efficacy of treatment.

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

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.

Abatacept inhibits radiographic progression in patients with rheumatoid arthritis: a retrospective analysis of 6 months of abatacept treatment in routine clinical practice. The ALTAIR study.

OBJECTIVES: Our objectives in this study were to determine the inhibitory effects of abatacept on joint damage and its clinical efficacy and safety in patients with rheumatoid arthritis (RA). METHODS: Fifty Japanese patients with RA were treated with abatacept for 24 weeks in routine clinical practice. RESULTS: At week 24, 20 % of patients achieved clinical remission [Simplified Disease Activity Index (SDAI) ≤3.3], whereas 50 % were in remission or had a low disease activity. Structural remission [progression of modified total Sharp score (ΔmTSS) ≤0.5] was achieved in 76 % of patients. The ΔmTSS decreased significantly from 7.1 ± 7.3 at baseline to 1.8 ± 5.7 at week 24. C-reactive protein (CRP) was the only independent prognostic factor for joint damage progression at week 24, whereas SDAI and matrix metalloproteinase-3 levels were not. A very high proportion of patients with CRP levels <1.5 mg/dl (88 %) achieved structural remission. In terms of safety, the retention rate for all patients was favorable (80 %), and stomatitis was the only adverse event observed. No patient withdrew from the study because of infections. CONCLUSIONS: Abatacept has favorable clinical and structural effects, inhibits radiographic progression, and has a good safety profile in routine clinical practice.

Discontinuation of adalimumab after attaining disease activity score 28-erythrocyte sedimentation rate remission in patients with rheumatoid arthritis (HONOR study): an observational study.

INTRODUCTION: Evidences of biologics-free disease control after discontinuing adalimumab (ADA) in rheumatoid arthritis (RA) patients in clinical practice have not been sufficiently investigated. Purpose of this study is to investigate whether disease activity score 28 (DAS28)- erythrocyte sedimentation rate (ESR) remission was preserved after discontinuation of ADA in patients with RA. METHODS: This is an observational but not a randomized controlled study. Among 197 RA patients who initiated with combination of ADA with concomitant MTX, 69 (35%) acquired DAS28 (ESR) < 2.6 for at least 24 weeks. Of those 69 patients, 51 went on ADA discontinuation with their consent, and finally 50 of those with follow-up of > 24 weeks were evaluated. The effect of discontinuing ADA on clinical disease activity, functional disability and radiographic progression were evaluated by DAS28 (ESR), the clinical disease activity index (CDAI) and the simplified disease activity index (SDAI), by a health assessment questionnaire-disability index (HAQ-DI) and by the modified total Sharp score (mTSS), respectively. RESULTS: The mean age of the participants was 59.5 years with the mean disease duration of 7.1 years. Out of the 50 patients, 29 (58%) were maintained in DAS28 (ESR) < 2.6 at 24 weeks after discontinuing ADA. A logistic regression analysis showed that DAS28 (ESR) at baseline significantly predicted a DAS28 (ESR) < 2.6 maintained after discontinuation of ADA, and a receiver-operating characteristic (ROC) analysis showed that the cut-off value of DAS28 (ESR) at discontinuation was 2.16. The mean HAQ-DI at six months after discontinuing ADA was 0.1 in patients who kept in DAS28 (ESR) < 2.6, and 94.9% (37/39) showed no evidence of radiographic progression (> 0.5 per year of a change in mTSS) at 1 year. CONCLUSIONS: It was possible to maintain DAS28 (ESR) < 2.6 after discontinuation of ADA without functional and radiographic progression and very low DAS28 (ESR) at the discontinuation was associated with successful ADA-free DAS28 (ESR) < 2.6 in patients with RA. TRIAL REGISTRATION: University Hospital Medical Information Network Identifier: UMIN000006669.

Dermal mast cell density in fingers reflects severity of skin sclerosis in systemic sclerosis.

BACKGROUND: Systemic sclerosis (SSc) is characterized by skin sclerosis, which develops from the distal extremities and spreads to the trunk. Although several reports have implied the involvement of mast cells in SSc based on examination of forearm skin specimens, there have been no studies that examined digital skin specimens. METHODS: Skin biopsies were obtained from the distal one-third of the forearm and between distal and proximal interphalangeal joints from 46 SSc patients, as well as from 29 non-SSc patients and normal controls. Dermal mast cells were detected histologically using NanoZoomer digital pathology. RESULTS: Dermal mast cell density was significantly higher in both the forearms and fingers in SSc patients compared with non-SSc patients and normal controls. Digital dermal mast cell density was significantly higher in patients with diffuse cutaneous SSc than in local cutaneous SSc patients and also in the anti-topoisomerase I antibody-positive group than in the negative group, though such tendency was not noted in the forearm dermis. Interestingly, digital dermal mast cell density tended to correlate negatively but significantly with disease duration, suggesting the possible involvement of dermal mast cells in the early pathological process. CONCLUSION: Digital accumulation of toluidine blue- and/or c-Kit-positive dermal mast cells appears to be involved in the early stages of the pathological processes of SSc, especially in patients positive for anti-topoisomerase I antibody.

Cell-autonomous role of TGFß and IL-2 receptors in CD4+ and CD8+ inducible regulatory T-cell generation during GVHD.

FoxP3(+) regulatory T cells (Tregs) suppress GVHD while preserving graft-versus-tumor effects, making them an attractive target for GVHD therapy. The donor-derived Treg pool can potentially be derived from the expansion of preexisting natural Tregs (nTregs) or from de novo generation of inducible Tregs (iTregs) from donor Tconvs in the transplantation recipient. Using an MHC-mismatched model of acute GVHD, in the present study we found that the Treg pool was comprised equally of donor-derived nTregs and iTregs. Experiments using various combinations of T cells from wild-type and FoxP3-deficient mice suggested that both preexisting donor nTregs and the generation of iTregs in the recipient mice contribute to protection against GVHD. Surprisingly, CD8(+)FoxP3(+) T cells represented approximately 70% of the iTreg pool. These CD8(+)FoxP3(+) T cells shared phenotypic markers with their CD4(+) counterparts and displayed suppressive activity, suggesting that they were bona fide iTregs. Both CD4(+) and CD8(+) Tregs appeared to be protective against GVHD-induced lethality and required IL-2 and TGFß receptor expression for their generation. These data illustrate the complex makeup of the donor-derived FoxP3(+) Treg pool in allogeneic recipients and their potential role in protection against GVHD.

Involvement of mast cells in systemic sclerosis.

Systemic sclerosis is characterized by tissue fibrosis, obliterative microangiopathy and immune abnormalities. The etiology of SSc is largely unknown and is known to be resistant to existing corticosteroid and immunosuppressive drugs. Therefore, establishment of a treatment strategy especially for SSc patients with organ involvement is strongly desired. Mast cells are widely recognized as effector cells in allergic disorders and other IgE-mediated immune responses. However, recently, mast cells have become known to play a role in bridging innate immunity and adaptive immunity. Additionally, there is growing evidence of mast cell to be involved in pathogenesis of rheumatoid arthritis, and is expected as a novel therapeutic target. We describe here the role of mast cell in SSc pathology and suggest as a novel therapeutic target.

C5a promotes migration, proliferation, and vessel formation in endothelial cells.

OBJECTIVES: The goal of this paper is to investigate the effects of activated complement C5a on vascular endothelium during vessel formation. METHODS: A human microvascular endothelial cell line (HMEC-1) derived from post-capillary venules in skin was used to measure DNA synthesis, proliferation and cell-cycle progression. In vitro ring-shaped formation by the cells was assessed by using type I collagen gel matrix and a cell-migration assay using the Chemotaxicell chamber. A Matrigel plug assay was performed to confirm the effect of C5a in vivo. RESULTS: C5a progressed the cell cycle of HMEC-1 into G2/M phases, and induced DNA synthesis and proliferation in a dose-dependent manner. C5a efficiently induced migration and ring-shaped structure formation both in vitro and in vivo. Furthermore, a C5a receptor antagonist (W-54011) suppressed all HMEC-1 activities including proliferation and migration. CONCLUSIONS: Proliferation, migration, and ring-shaped formation by HMEC-1 cells was induced by C5a. The actions were efficiently inhibited by a specific antagonist against C5a. Our results implicated C5a in vessel formation and as a potent target for management of inflammatory diseases.

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.

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.

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.

Growth suppression of human mast cells expressing constitutively active c-kit receptors by JNK inhibitor SP600125.

Activation of c-jun N-terminal kinase (JNK) through c-kit-mediated phosphatidylinositol 3 (PI3) and Src kinase pathways plays an important role in cell proliferation and survival in mast cells. Gain-of-function mutations in c-kit are found in several human neoplasms. Constitutive activation of c-kit has been observed in human mastocytosis and gastrointestinal stromal tumor. In the present study, we demonstrate that an anthrapyrazole SP600125, a reversible ATP-competitive inhibitor of JNK inhibits proliferation of human HMC-1 showed constitutive activation of JNK/c-Jun, and the inhibitory effect of SP600125 on cell proliferation was associated with cell cycle arrest at the G1 phase and apoptosis accompanied by the cleavage of caspase-3 and PARP. Caspase-3 inhibitor Z-DEVD-FMK almost completely inhibited SP600125-induced apoptosis of HMC-1 cells. In contrast, caspase-9 inhibitor Z-LEHD-FMK failed to block SP600125-induced apoptosis. Following Sp600125 treatment, down-regulation of cyclin D3 protein expression, but not p53 was also observed. Thus, JNK/c-Jun is essential for proliferation and survival of HMC-1 cells. The results obtained from the present study suggest the possibility that JNK/c-Jun may be a therapeutic target in diseases associated with mutations in the catalytic domain of c-kit.

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.