Network


Latest external collaboration on country level. Dive into details by clicking on the dots.

Hotspot


Dive into the research topics where Ryoki Hara is active.

Publication


Featured researches published by Ryoki Hara.


The Journal of Rheumatology | 2012

Efficacy and limitation of infliximab treatment for children with Kawasaki disease intractable to intravenous immunoglobulin therapy: report of an open-label case series.

Masaaki Mori; Tomoyuki Imagawa; Ryoki Hara; Masako Kikuchi; Takuma Hara; Tomo Nozawa; Takako Miyamae; Shumpei Yokota

Objective. Kawasaki disease (KD) is an acute febrile disease in infants and young children. Five percent to 8% of cases will be complicated with coronary dilatation or aneurysm, although introduction of high-dose intravenous immunoglobulin (IVIG) therapy has provided remarkable results for reducing the frequency of cardiac involvement. We describe the results of an open-label trial of infliximab, an anti-tumor necrosis factor-α monoclonal antibody, for suppressing the progression of coronary artery lesions in cases of KD refractory to extensive IVIG therapy. Plasma exchange (PE) was available as a rescue therapy for patients refractory to infliximab. Methods. Twenty eligible patients fulfilled the diagnostic criteria for KD, and were primarily treated with IVIG up to 4 g/kg. “Refractory to IVIG” was defined as persisting or reemerging fever > 38°C and positive fractional changes of C-reactive protein, white blood cell counts, or neutrophil counts 48 hours after IVIG infusion. These cases were treated with infliximab, 5 mg/kg, which should begin within 10 days of disease onset. PE for patients refractory to infliximab was performed with 5% albumin. Results. There was rapid improvement of inflammatory symptoms as well as normalization of the inflammatory markers. Sequential examination by echocardiography up to disease Day 30 revealed that the inflamed and mildly dilated coronary artery at the beginning of the study regressed to normal size in the convalescent phase. Two out of 20 patients showed incomplete improvement of inflammatory symptoms after infliximab treatment, and were provided with PE therapy, with no complications. Conclusion. Eighteen of 20 patients were effectively treated with infliximab, and 2 cases were effectively treated with PE to prevent progression to coronary artery lesions. No adverse event such as anaphylactoid reaction, heart failure, severe infectious diseases, or tuberculosis was observed in this trial.


British Journal of Clinical Pharmacology | 2011

Influence of polymorphisms within the methotrexate pathway genes on the toxicity and efficacy of methotrexate in patients with juvenile idiopathic arthritis

Masakatsu Yanagimachi; Takuya Naruto; Takuma Hara; Masako Kikuchi; Ryoki Hara; Takako Miyamae; Tomoyuki Imagawa; Masaaki Mori; Tetsuji Kaneko; Satoshi Morita; Hiroaki Goto; Shumpei Yokota

AIMS We investigated whether several polymorphisms within the methotrexate (MTX) pathway genes were related to the toxicity and efficacy of MTX in 92 Japanese patients with articular-type juvenile idiopathic arthritis (JIA). METHODS Eight gene polymorphisms within the MTX pathway genes, namely, RFC, BCRP, MTHFR (two), FPGS, γ-glutamyl hydrolase (GGH; two) and ATIC, were genotyped using TaqMan assays. Liver dysfunction was defined as an increase in alanine transaminase to five times the normal upper limit. Non-responders to MTX were defined as patients refractory to MTX and were therefore treated with biologics. RESULTS The non-TT genotype at GGH T16C was associated with a high risk of liver dysfunction (P=0.028, odds ratio=6.90, 95% confidence interval 1.38-34.5), even after adjustment for the duration of MTX treatment. A longer interval from disease onset to treatment (8.5 and 21.3 months, P=0.029) and rheumatoid factor positivity (P=0.026, odds ratio=2.87, 95% confidence interval 1.11-7.39) were associated with lower efficacy of MTX. CONCLUSIONS The non-TT genotype at GGH T16C was associated with a high risk of liver dysfunction, presumably because the C allele of GGH C16T may reduce the activity of GGH. The time interval before MTX treatment and rheumatoid factor positivity were associated with the efficacy of MTX treatment. The pharmacogenetics of the MTX pathway genes affects the toxicity and efficacy of MTX in Japanese JIA patients.


The Journal of Rheumatology | 2011

Association of IRF5 Polymorphisms with Susceptibility to Macrophage Activation Syndrome in Patients with Juvenile Idiopathic Arthritis

Masakatsu Yanagimachi; Takuya Naruto; Takako Miyamae; Takuma Hara; Masako Kikuchi; Ryoki Hara; Tomoyuki Imagawa; Masaaki Mori; Hidenori Sato; Hiroaki Goto; Shumpei Yokota

Objective. Systemic-onset juvenile idiopathic arthritis (systemic JIA) and macrophage activation syndrome (MAS), the most devastating complication of systemic JIA, are characterized by abnormal levels of proinflammatory cytokines. Interferon regulatory factor 5 (IRF5) is a member of the IRF family of transcription factors, and acts as a master transcription factor in the activation of genes encoding proinflammatory cytokines. Polymorphisms in the IRF5 gene have been associated with susceptibility to autoimmune diseases such as systemic lupus erythematosus (SLE) and rheumatoid arthritis. Our aim was to assess associations of IRF5 gene polymorphisms with susceptibility to systemic JIA and MAS. Methods. Three IRF5 single-nucleotide polymorphisms (rs729302, rs2004640, and rs2280714) were genotyped using TaqMan assays in 81 patients with systemic JIA (33 with MAS, 48 without) and 190 controls. Results. There were no associations of the IRF5 gene polymorphisms or haplotypes under study with susceptibility to systemic JIA. There was a significant association of the rs2004640 T allele with MAS susceptibility (OR 4.11; 95% CI 1.84, 9.16; p = 0.001). The IRF5 haplotype (rs729302 A, rs2004640 T, and rs2280714 T), which was reported as conferring an increased risk of SLE, was significantly associated with MAS susceptibility in patients with systemic JIA (OR 4.61; 95% CI 1.73, 12.3; p < 0.001). Conclusion. IRF5 gene polymorphism is a genetic factor influencing susceptibility to MAS in patients with systemic JIA, and IRF5 contributes to the pathogenesis of MAS in these patients.


Modern Rheumatology | 2012

Safety and response to influenza vaccine in patients with systemic-onset juvenile idiopathic arthritis receiving tocilizumab

Toshihiko Shinoki; Ryoki Hara; Utako Kaneko; Takako Miyamae; Tomoyuki Imagawa; Masaaki Mori; Shumpei Yokota

ObjectiveWe investigated the safety and efficacy of administering influenza vaccines to patients with systemic-onset juvenile idiopathic arthritis (sJIA) treated with tocilizumab.Patients and methodsThe subjects were 27 sJIA patients treated with tocilizumab and 17 healthy age- and sex-matched volunteers. Serum samples were collected prior to and 4–7 weeks after vaccination. Hemagglutination inhibition values of the vaccine were taken as the antibody titers. The duration of tocilizumab administration and the daily doses of prednisolone per unit body weight were analyzed to identify factors affecting the responses of the sJIA patients to influenza vaccination. We questioned all the subjects about whether they had contracted influenza and whether they had had adverse reactions to the influenza vaccination. We compared steroid doses in sJIA patients before and after vaccination to document any worsening of the underlying disease.ResultsThe efficacy of influenza vaccination did not differ significantly between the sJIA group and the healthy controls. The duration of tocilizumab administration did not affect the response of the sJIA patients to the influenza vaccination. None of the sJIA patients experienced either severe adverse reactions or disease exacerbation after the influenza vaccination.ConclusionWe found that sJIA patients treated with tocilizumab could be effectively and safely immunized with the influenza vaccine.


Pediatric Rheumatology | 2010

Effect of anakinra on arthropathy in CINCA/NOMID syndrome

Takako Miyamae; Yutaka Inaba; Gen Nishimura; Masako Kikuchi; Takayuki Kishi; Ryoki Hara; Utako Kaneko; Toshihiko Shinoki; Tomoyuki Imagawa; Shumpei Yokota

CINCA/NOMID is an autoinflammatory disorder characterized by the triad of neonatal onset of cutaneous symptoms, chronic meningitis, and recurrent fever and it presents with distinctive osteoarthropathy, synovitis mainly of the large joints and overgrowth of epimetaphyseal cartilage, particularly of the long bones. The cartilage overgrowth eventually causes osseous overgrowth and deformity that persists beyond skeletal maturity and leads to limb length discrepancy, joint contracture, and early degenerative arthropathy. Autoinflammation in CAPS/NOMID has been proven to derive from excessive release of interleukin-1 (IL-1). It has been well documented that the IL-1 receptor antagonist anakinra (Kineret(R)) helps mitigate systemic inflammation in the disorder. However, a general consensus has not been reached on its beneficial effect on osteoarthropathy. The case of a girl with CINCA/NOMID syndrome who showed dramatic improvement of osteoarthropathy after anakinra treatment is reported. A 4-year-old girl suffered at the age of 10 months from a generalized urticarial skin lesion with recurrent episodes of fever and growth disorder. Blood examination revealed persistent massive neutrophilia, anemia and intense acute phase response. She manifested knee joint swelling with limited ROM when she was 20 months old and was diagnosed as being CINCA/NOMID based on characteristic findings of radiograph despite negative CIAS1 mutation. Radiological examination demonstrated metaphyseal fraying and cupping and widening of the growth plate in the distal femur. MR imaging showed mottled gadolinium enhancement at the chondrosseous junction. Neither significant joint effusion nor synovitis was identified. At 2 years and 7 months of age, anakinra, 2 mg/kg/day given by regular daily subcutaneous injections, was started. A few days after the initiation of the treatment, her clinical symptoms and laboratory findings of active inflammation were promptly alleviated. She was not able to walk unaided prior to the treatment, but she walked independently 1 month after the treatment. Follow-up radiographs and MR imaging showed that growth plate widening and gadolinium enhancement at the chondrosseous junction were less conspicuous. Furthermore, longitudinal growth of the femur and tibia was identified during 20 months of observation.


PLOS ONE | 2013

Analysis of Gender Differences in Genetic Risk: Association of TNFAIP3 Polymorphism with Male Childhood-Onset Systemic Lupus Erythematosus in the Japanese Population

Keisuke Kadota; Masaaki Mori; Masakatsu Yanagimachi; Takako Miyamae; Takuma Hara; Taichi Kanetaka; Tomo Nozawa; Masako Kikuchi; Ryoki Hara; Tomoyuki Imagawa; Tetsuji Kaneko; Shumpei Yokota

Background Systemic lupus erythematosus (SLE) is a systemic multisystem autoimmune disorder influenced by genetic background and environmental factors. Our aim here was to replicate findings of associations between 7 of the implicated single nucleotide polymorphisms (SNPs) in IRF5, BLK, STAT4, TNFAIP3, SPP1, TNIP1 and ETS1 genes with susceptibility to childhood-onset SLE in the Japanese population. In particular, we focused on gender differences in allelic frequencies. Methodology/Principal Findings The 7 SNPs were genotyped using TaqMan assays in 75 patients with childhood-onset SLE and in 190 healthy controls. The relationship between the cumulative number of risk alleles and SLE manifestations was explored in childhood-onset SLE. Logistic regression was used to test the effect of each polymorphism on susceptibility to SLE, and Wilcoxon rank sum testing was used for comparison of total risk alleles. Data on rs7574865 in the STAT4 gene and rs9138 in SPP1 were replicated for associations with SLE when comparing cases and controls (corrected P values ranging from 0.0043 to 0.027). The rs2230926 allele of TNFAIP3 was associated with susceptibility to SLE in males, but after Bonferroni correction there were no significant associations with any of the other four SNPs in IRF5, BLK, TNIP1 and ETS1 genes. The cumulative number of risk alleles was significantly increased in childhood-onset SLE relative to healthy controls (P = 0.0000041). Male SLE patients had a slightly but significantly higher frequency of the TNFAIP3 (rs2230926G) risk allele than female patients (odds ratio [OR] = 4.05, 95% confidence interval [95%CI] = 1.46–11.2 P<0.05). Conclusions Associations of polymorphisms in STAT4 and SPP1 with childhood-onset SLE were confirmed in a Japanese population. Although these are preliminary results for a limited number of cases, TNFAIP3 rs2230926G may be an important predictor of disease onset in males. We also replicated findings that the cumulative number of risk alleles was significantly increased in childhood-onset SLE.


Journal of Human Genetics | 2011

De novo 19q13.42 duplications involving NLRP gene cluster in a patient with systemic-onset juvenile idiopathic arthritis.

Hiromi Tadaki; Hirotomo Saitsu; Akira Nishimura-Tadaki; Tomoyuki Imagawa; Masako Kikuchi; Ryoki Hara; Utako Kaneko; Takayuki Kishi; Takako Miyamae; Noriko Miyake; Hiroshi Doi; Yoshinori Tsurusaki; Haruya Sakai; Shumpei Yokota; Naomichi Matsumoto

Systemic-onset juvenile idiopathic arthritis (s-JIA) is a rare inflammatory disease classified as a subtype of chronic childhood arthritis, manifested by spiking fever, erythematous skin rash, pericarditis and hepatosplenomegaly. The genetic background underlying s-JIA remains poorly understood. To detect disease-related copy number variations (CNVs), we performed single-nucleotide polymorphism array analysis in 50 patients with s-JIA. We detected many CNVs, but most of them were inherited from either of normal-phenotype parents. However, in one patient, we could identify two de novo microduplications at 19q13.42 with the size of 77 and 622 kb, separated by a 109-kb segment of normal copy number. The duplications encompass NLRP family (NLRP2, NLRP9 and NLRP11) as well as IL11 and HSPBP1, all of which have an important role in inflammatory pathways. These genes may significantly contribute to the pathogenesis of s-JIA.


The Journal of Rheumatology | 2014

Discrepancy Between Clinical and Radiological Responses to Tocilizumab Treatment in Patients with Systemic-onset Juvenile Idiopathic Arthritis

Chie Aoki; Yutaka Inaba; Hyonmin Choe; Utako Kaneko; Ryoki Hara; Takako Miyamae; Tomoyuki Imagawa; Masaaki Mori; Mari S. Oba; Shumpei Yokota; Tomoyuki Saito

Objective. Tocilizumab (TCZ), an antiinterleukin-6 receptor monoclonal antibody, is clinically beneficial in patients with systemic-onset juvenile idiopathic arthritis (sJIA). We investigated the clinical and radiological outcomes of TCZ therapy in patients with sJIA. Methods. We retrospectively evaluated 2 clinical trials (NCT00144599 and NCT00144612) involving 40 patients with sJIA who received intravenous TCZ (8 mg/kg) every 2 weeks. Clinical data and radiographs of the hands and large joints were assessed before and during TCZ treatment. The Poznanski score, modified Larsen scores of the hands and large joints, and Childhood Arthritis Radiographic Score of the Hip (CARSH) were recorded. Results. After a mean duration of 4.5 years of TCZ treatment, clinical data had improved significantly, the mean Poznanski score improved from −1.5 to −1.1, the mean Larsen score of the hands deteriorated from 7.0 to 10.0, the mean Larsen score for the large joints deteriorated from 5.9 to 6.8, and the CARSH worsened from 3.9 to 6.2. The Larsen score for the large joints improved in 11 cases (28%), remained unchanged in 8 cases (20%), and worsened in 21 cases (52%). Matrix metalloproteinase 3 (MMP-3) levels remained significantly higher (278 mg/dl) in patients with worsened Larsen scores than in patients with improved or unchanged scores (65 mg/dl). Logistic regression analysis showed that older age at disease onset was a significant risk factor for radiographic progression. Conclusion. The modified Larsen score of the large joints deteriorated in half the patients who had high MMP-3 levels during TCZ treatment and who were significantly older at disease onset.


Journal of Human Genetics | 2011

Association of HLA-A * 02:06 and HLA-DRB1 * 04:05 with clinical subtypes of juvenile idiopathic arthritis

Masakatsu Yanagimachi; Takako Miyamae; Takuya Naruto; Takuma Hara; Masako Kikuchi; Ryoki Hara; Tomoyuki Imagawa; Masaaki Mori; Tetsuji Kaneko; Hiroaki Goto; Satoshi Morita; Nobuhisa Mizuki; Akinori Kimura; Shumpei Yokota

Juvenile idiopathic arthritis (JIA) is one of the most common forms of pediatric chronic arthritis. JIA is a clinically heterogeneous disease. Therefore, the genetic background of JIA may also be heterogeneous. The aim of this study was to investigate associations between human leukocyte antigen (HLA) and susceptibility to JIA and/or uveitis, which is one of the most devastating complications of JIA. A total of 106 Japanese articular JIA patients (67 with polyarthritis and 39 with oligoarthritis) and 678 healthy controls were genotyped for HLA-A, -B and -DRB1 by PCR-sequence-specific oligonucleotide probe methodology. HLA-A*02:06 was the risk factor for JIA accompanied by uveitis after adjustment for clinical factors (corrected P-value <0.001, odds ratio (OR) 11.7, 95% confidence interval (CI) 3.2–43.0). On the other hand, HLA-DRB1*04:05 was associated with polyarticular JIA (corrected P-value <0.001, OR 2.9, 95% CI 1.7–4.8). We found an association of HLA-A*02:06 with susceptibility to JIA accompanied by uveitis, which might be considered a separate clinical JIA entity. We also found an association between HLA-DRB1*04:05 and polyarticular JIA. Thus, clinical subtypes of JIA can be classified by the presence of the specific HLA alleles, HLA-A*02:06 and DRB1*04:05.


Modern Rheumatology | 2015

Pathogenesis of systemic inflammatory diseases in childhood: “Lessons from clinical trials of anti-cytokine monoclonal antibodies for Kawasaki disease, systemic onset juvenile idiopathic arthritis, and cryopyrin-associated periodic fever syndrome”

Shumpei Yokota; Masako Kikuchi; Tomo Nozawa; Taichi Kanetaka; Tomomi Sato; K Yamazaki; Nodoka Sakurai; Ryoki Hara; Masaaki Mori

Abstract Inflammation has often been considered to be a nonspecific response and to play a bridging role in the activation of adaptive immunity. However, it is now accepted that inflammation is the product of an independent innate immune system closely linked to the adaptive immune system. The key mediators of inflammation are inflammatory cytokines, as determined by multiple lines of evidence both in vitro and in vivo. Due to the crucial role of inflammatory cytokines in the pathogenesis of autoimmune disorders, anti-cytokine treatment has been developed as a therapy for rheumatoid arthritis, juvenile idiopathic arthritis (JIA), and inflammatory bowel diseases. We recently completed several clinical trials of anti-cytokine treatment for children with systemic inflammatory diseases: anti-IL-6 receptor monoclonal antibody (tocilizumab) for children with two subtypes of JIA (poly-JIA and systemic JIA), anti-TNF-α monoclonal antibody (infliximab) for children with Kawasaki disease, and anti-IL-1-β monoclonal antibody (canakinumab) for children with cryopyrin-associated periodic syndrome. This review summarizes the basis of inflammation in terms of innate immunity and adaptive immunity in these systemic inflammatory diseases, clinical efficacy, and tolerability of these biologic agents, and attempts to determine the roles of individual inflammatory cytokines in disease pathogenesis.

Collaboration


Dive into the Ryoki Hara's collaboration.

Top Co-Authors

Avatar

Masako Kikuchi

Yokohama City University

View shared research outputs
Top Co-Authors

Avatar

Masaaki Mori

Yokohama City University Medical Center

View shared research outputs
Top Co-Authors

Avatar

Shumpei Yokota

Yokohama City University

View shared research outputs
Top Co-Authors

Avatar
Top Co-Authors

Avatar

Takako Miyamae

Yokohama City University

View shared research outputs
Top Co-Authors

Avatar

Tomo Nozawa

Yokohama City University

View shared research outputs
Top Co-Authors

Avatar
Top Co-Authors

Avatar

Nodoka Sakurai

Yokohama City University

View shared research outputs
Top Co-Authors

Avatar
Top Co-Authors

Avatar

Takuma Hara

Yokohama City University Medical Center

View shared research outputs
Researchain Logo
Decentralizing Knowledge