Yoshiya Tanaka

Increased Syk phosphorylation leads to overexpression of TRAF6 in peripheral B cells of patients with systemic lupus erythematosus

Objective Activation of B cells is a hallmark of systemic lupus erythematosus (SLE). Syk and TRAF6 are key signaling molecules in B-cell activation through BCR and CD40/TLR, respectively. Nevertheless, whether expression of Syk and TRAF6 is altered in SLE B cells remains unknown. Methods Phosphorylation and/or expression of Syk and TRAF6 were analyzed by flow cytometry in peripheral blood mononuclear cells isolated from SLE patients. Results Pronounced phosphorylation and expression of Syk were noted in B cells from SLE patients compared with healthy donors. Levels of Syk phosphorylation correlated with the disease activity score. TRAF6 was significantly over-expressed in B cells of SLE patients as compared with healthy donors, and significant correlation of levels of TRAF6 expression and Syk phosphorylation was observed in SLE patients. Levels of TRAF6 expression were more pronounced in CD27+ memory B cells than in CD27-naïve B cells. In vitro treatment of SLE B cells with a Syk inhibitor (BAY61-3606) reduced Syk phosphorylation as well as TRAF6 expression. Conclusion Our results suggest that the activated Syk-mediated TRAF6 pathway leads to aberrant activation of B cells in SLE, and also highlight Syk as a potential target for B-cell-mediated processes in SLE.

Correlation of T follicular helper cells and plasmablasts with the development of organ involvement in patients with IgG4-related disease

ObjectivenTo assess the role of an abnormal immune network in the pathology of IgG4-related disease (IgG4-RD).nnnMethodsnSixteen patients diagnosed with IgG4-RD at our institution were selected. Peripheral immunocompetent cells were immunophenotyped by multicolour flow cytometry to assess the association between clinical manifestation and pathological findings.nnnResultsnCompared with healthy controls, IgG4-RD patients showed comparable proportions of Th1 and Th17 cells, but higher proportions of Treg and follicular helper T (Tfh) cells. Further, the proportions of class-switched memory B cells and plasmablasts were higher in patients. Among all phenotypes, in particular, the plasmablast proportion increased from 4.2% (controls) to 16.5% (patients). The serum IgG levels were found to be correlated with the proportions of plasmablasts and Tfh cells, but not with those of other T cell subsets. In patients with extraglandular symptoms, only plasmablasts, Tfh cells and memory Treg cells were increased. Histopathological examination revealed a marked Tfh (CD4+ Bcl6+) cell infiltration; the increase of Tfh cells in the peripheral blood thus reflected the degree of Tfh cell infiltration into the tissue. Although steroid therapy reduced plasmablast and Tfh cell proportions, the memory Treg cell proportion remained unchanged.nnnConclusionnThe association found between Tfh cells and plasmablasts, linked with biological plausibility, suggests that Tfh cells contribute to the pathogenesis of IgG4-RD. Our results also suggested that controlling the Tfh cell-plasmablast axis could be a novel therapeutic strategy for treating IgG4-RD.

Differential effects of biological DMARDs on peripheral immune cell phenotypes in patients with rheumatoid arthritis

ObjectivenThe aim of this study was to assess the therapeutic effects of biological DMARDs (bDMARDs) on the diversity of immune cell phenotypes in peripheral blood of patients with RA.nnnMethodsnPeripheral immune cell phenotypes were determined in 108 RA patients who were non-responsive to conventional DMARDs and 33 healthy control subjects by eight-colour flow cytometry. We also examined the correlation between the phenotypes and clinical findings and assessed the effects of 24-week treatment with bDMARDs.nnnResultsnThe proportions of T follicular helper (Tfh) cells, IgD- CD27- double negative B cells and plasmacytoid dendritic cells (pDCs) were higher in patients with active RA than in healthy control. The percentages of memory T cells, Th17 and Tfh cells correlated with autoantibody titres, whereas that of plasmablasts correlated with disease activity scores. Treatment with TNF inhibitors reduced the proportion of pDCs, while tocilizumab reduced the proportion of double-negative B cells but increased naïve and activated Treg cells. Abatacept treatment resulted in marked decrease in the proportion of activated Tfh but slightly reduced Th17 and Treg cells. The proportion of Tfh cells was an independent and significant predictor of the response to abatacept therapy.nnnConclusionnMolecular targeted therapies induced different changes in different immune cell phenotypes. Among the phenotypes, Tfh cells seem a potential target for abatacept. Immunophenotypic analysis might be useful for prediction of the response to bDMARDs.

Peripheral immunophenotyping identifies three subgroups based on T cell heterogeneity in lupus patients

To elucidate the diversity of systemic lupus erythematosus (SLE) based on immunophenotyping.

Metabolic Reprogramming Commits Differentiation of Human CD27 + IgD + B Cells to Plasmablasts or CD27 − IgD − Cells

B cells play a crucial role in the pathogenesis of autoimmune diseases, such as systemic lupus erythematosus (SLE). However, the relevance of the metabolic pathway in the differentiation of human B cell subsets remains unknown. In this article, we show that the combination of CpG/TLR9 and IFN-α markedly induced the differentiation of CD27+IgD+ unswitched memory B cells into CD27hiCD38hi plasmablasts. The response was accompanied by mammalian target of rapamycin complex 1 (mTORC1) activation and increased lactate production, indicating a shift to glycolysis. However, CpG alone induced the differentiation of unswitched memory B cells into CD27−IgD− memory B cells with high cytokine production, but such differentiation was suppressed by IFN-α. AMP-activated protein kinase activation enhanced the differentiation to CD27−IgD− B cells, but it attenuated mTORC1 activation and differentiation into plasmablasts. High mTORC1 activation was noted in CD19+ B cells of patients with SLE and correlated with plasmablast differentiation and disease activity. Taken together, differential metabolic reprogramming commits the differentiation of human unswitched memory B cells into plasmablasts (the combination of CpG and IFN-α amplifies mTORC1-glycolysis pathways) or CD27−IgD− memory B cells (CpG alone amplifies the AMP-activated protein kinase pathway). The former metabolic pathway may play a pivotal role in SLE.

Efficacy and safety of anti-CD20 antibody rituximab for patients with refractory systemic lupus erythematosus:

Objective We examined the efficacy and safety of rituximab in patients with refractory systemic lupus erythematosus (SLE). Methods The study enrolled 63 SLE patients who were treated with rituximab between 2002 and 2015. The participants underwent a battery of tests before treatment and at one year. Treatment ranged from two to four times at 500 or 1000u2009mg. Results Baseline characteristics were males:femalesu2009=u20096:57, age 33.9 years, and disease duration 87.2 months. The primary endpoint: The rate of major clinical response (MCR) was 60% while the partial clinical response (PCR) was 25%. Thirty of 36 (83%) patients with lupus nephritis (WHO II: 2, III: 5, IV: 22, V: 4, IV+V: 2, not assessed: 1) and 22 of 24 patients (92%) with neuropsychiatric SLE, who could be followed at one year, showed changes from BILAG A or B score to C or D score at one year. Multivariate analysis identified high anti-dsDNA antibody and shorter disease duration as significant determinants of MCR at one year. Repeat examination was conducted at five years. Primary failure was recorded in 8.8% and secondary failure in 32.4% (time to relapse: 24.4 months). Rituximab was well tolerated although 65 adverse events, mostly infections, were recorded within one year. Conclusion Rituximab is potentially efficacious for the treatment of patients with refractory SLE.

Comparison of effects of anagliptin and alogliptin on serum lipid profile in type 2 diabetes mellitus patients

Anagliptin (ANA) improves dyslipidemia in addition to blood glucose levels. However, there are no comparative studies on the effects of ANA and other dipeptidyl peptidase‐4 inhibitors on serum lipid profile. We compared the effects of ANA on serum lipid profile with those of alogliptin (ALO) in type 2 diabetes mellitus outpatients.

The Effects of Mitiglinide and Repaglinide on Postprandial Hyperglycemia in Patients Undergoing Methylprednisolone Pulse Therapy

One adverse effect of methylprednisolone (MP) pulse therapy is an acute dose-dependent increase in the blood glucose level. Five patients with thyroid ophthalmopathy but normal glucose tolerance received MP pulse therapy (3 cycles, 3 days/week) and were assessed by continuous glucose monitoring. Steroid therapy increased the mean sensor glucose level, and all patients developed steroid-induced diabetes. The patients were treated alternately with mitiglinide (30 mg/day) and repaglinide (1.5 mg/day) during the second or third MP pulse therapy. The sensor glucose levels before lunch and dinner were more favorable during treatment with repaglinide than during treatment with mitiglinide. Repaglinide may be more clinically appropriate than mitiglinide.

Comparison of the Effects of Teneligliptin and Sitagliptin, Two Dipeptidyl Peptidase 4 Inhibitors with Different Half-Lives, on Glucose Fluctuation and Glucagon-Like Peptide-1 in Type 2 Diabetes Mellitus

Our purpose was to determine the effects of teneligliptin and sitagliptin, two dipeptidyl peptidase 4 inhibitors (DPP4-Is) with different half-lives, on glycemic variability and glucagon-like peptide-1 (GLP-1) levels in Japanese patients with type 2 diabetes mellitus (T2DM). The study subjects were 14 drug-naïve patients with T2DM who were allocated to either a 20 mg/day teneligliptin group (n = 7) or a 50 mg/day sitagliptin group (n = 7) for 7 days, then switched to the other treatment for another 7 days. Meal tolerance tests were performed at the time of no treatment, and after treatment with each DPP4-Is at supper. We evaluated the effects of each drug on glucose fluctuation using continuous glucose monitoring (CGM). There was no significant difference between the two groups in the primary endpoint (maximum glucose level after supper), nor in the secondary endpoint: area under the curve (AUC) for plasma glucose (≥140 mg/dl) after supper (18:00 - 24:00). Teneligliptin significantly improved the AUC for plasma glucose (≥140 mg/dl) after supper (20:00-24:00) (P = 0.048), and also significantly increased the GLP-1 level at 30 minutes after the meal load (P = 0.030). No serious adverse effects were noted in either group, apart from a few episodes of asymptomatic hypoglycemia. A daily dose of teneligliptin improved the AUC for plasma glucose at 20:00 to 24:00 (≥140 mg/dl) after the meal tolerance test, and also significantly increased the levels of activated GLP-1 after the test meal.

Use of mesenchymal stem cells seeded on the scaffold in articular cartilage repair

Articular cartilage has poor capacity for repair. Once damaged, they degenerate, causing functional impairment of joints. Allogeneic cartilage transplantation has been performed for functional recovery of articular cartilage. However, there is only a limited amount of articular cartilage available for transplantation. Mesenchymal stem cells (MSCs) could be potentially suitable for local implantation. MSCs can differentiate into chondrocytes. Several studies have demonstrated the therapeutic potential of MSCs in the repair of articular cartilage in animal models of articular cartilage damage and in patients with damaged articular cartilage. To boost post-implantation MSC differentiation into chondrocytes, the alternative delivery methods by scaffolds, using hyaluronic acid (HA) or poly-lactic-co-glycolic-acid (PLGA), have developed. In this review, we report recent data on the repair of articular cartilage and discuss future developments.