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Featured researches published by Keijiro Sato.


International Journal of Hematology | 2010

Lymphadenopathy of IgG4-related sclerosing disease: three case reports and review of literature

Ikuo Shimizu; Kentaro Nasu; Keijiro Sato; Hiromitsu Ueki; Daigo Akahane; Masahiko Sumi; Mayumi Ueno; Naoaki Ichikawa; Naoko Asano; Masaru Kojima; Hikaru Kobayashi

Immunoglobulin (Ig) G4-related sclerosing disease is a recently described syndrome characterized by lymphoplasmacytic infiltration of exocrine glands or extranodal tissues and elevated serum IgG4. We report three cases of lymphadenopathy secondary to IgG4-related sclerosing disease. Histologic features of involved lymph nodes included interfollicular immunoblasts and plasma cells, similar to Castleman’s disease. The percentage of IgG4-/IgG-positive plasma cells in the three patients was markedly elevated (30, 50, and 60%). Administration of prednisolone led to remission in every case. One of three cases was consulted to our hospital due to suspected diagnosis of angioimmunoblastic T cell lymphoma (AITL). The case demonstrates many clinical and pathologic similarities between IgG4-related sclerosing disease and AITL. Pathological similarities between AITL and the lymphoplasmacytic subtype of IgG4-sclerosing disease have recently been reported. It is important to accurately diagnose IgG4-related lymphadenopathy given its ready response to steroid therapy and the potential for misdiagnosing lymphoma on clinical grounds.


PLOS ONE | 2016

Exogenous Magnesium Chloride Reduces the Activated Partial Thromboplastin Times of Lupus Anticoagulant-Positive Patients.

Takayoshi Tokutake; Yuji Shimada; Wataru Takeda; Keijiro Sato; Yuki Hiroshima; Takehiko Kirihara; Ikuo Shimizu; Hideyuki Nakazawa; Hikaru Kobayashi; Fumihiro Ishida

The activated partial thromboplastin time (APTT) assay is a basic hemostatic assay based on the time it takes for clots to form in plasma samples after the addition of calcium chloride. It is used to screen for various coagulation disorders. Several previous reports have suggested that magnesium (Mg) might contribute to coagulation reactions by binding to specific coagulation proteins. We investigated the effects of Mg on the APTT. In healthy controls, the APTT was significantly prolonged in proportion to the increase in the concentration of magnesium chloride in the range from 2.1 to 16.7 mmol/L. Among eight samples from patients with various disorders that exhibited prolonged APTT, two samples demonstrated shorter APTT when Mg was added, both of which were from patients that were positive for lupus anticoagulant. When we examined 206 clinical APTT samples, we found that Mg shortened the APTT of two samples. These two samples were also from lupus anticoagulant-positive patients (p-value: <0.003). Our findings regarding the unique effects of exogenous Mg on the APTT of lupus anticoagulant-positive patients might shed light on the role of Mg in APTT assays and lead to the development of a novel screening method for lupus anticoagulant.


Cancer Medicine | 2014

Use of percutaneous image‐guided coaxial core‐needle biopsy for diagnosis of intraabdominal lymphoma

Ikuo Shimizu; Yoichi Okazaki; Wataru Takeda; Takehiko Kirihara; Keijiro Sato; Yuko Fujikawa; Toshimitsu Ueki; Yuki Hiroshima; Masahiko Sumi; Mayumi Ueno; Naoaki Ichikawa; Hikaru Kobayashi

Although pathological diagnosis is essential for managing malignant lymphoma, intraabdominal lesions are generally difficult to approach due to the invasiveness of abdominal surgery. Here, we report the use of percutaneous image‐guided coaxial core‐needle biopsy (CNB) to obtain intraabdominal specimens for diagnosing intraabdominal lymphomas, which typically requires histopathological and immunohistochemical evaluation. We retrospectively reviewed consecutive cases involving computed tomography (CT)‐ or ultrasonography (US)‐guided CNB to obtain pathological specimens for intraabdominal lesions from 1999 to 2011. Liver, spleen, kidney, and inguinal node biopsies were excluded. We compared CNBs with laparotomic biopsies. A total of 66 CNBs were performed for 59 patients (32 males, 27 females; median age, 63.5), including second or third repeat procedures. Overall diagnostic rate was 88.5%. None of the patients required additional surgical biopsies. Notably, the median interval between recognition of an intraabdominal mass and biopsy was only 1 day. Forty‐five procedures were performed for hematological malignancies. Adequate specimens were obtained for histopathological diagnosis in 86% of cases. Flow cytometry detected lymphoma cells in 79.5% of cases. Twelve patients (nine males, three females; median age, 60) were eligible for surgical biopsy. While every postoperative course was satisfactory, median duration from lesion recognition to therapy initiation for lymphoma cases was significantly shorter for CNB than for surgical biopsy (14 vs. 35 days). While one‐fourth of the patients were not eligible for the procedures, CNB is safe and highly effective for diagnosis of intraabdominal lymphomas. This method significantly improves sampling and potentially helps attain immunohistological distinction, allowing for more timely therapy initiation.


European Journal of Haematology | 2011

Reduced-intensity cord blood transplantation without prior remission induction therapy induces durable remission in adult patients with relapsed acute leukemia after the first allogeneic transplantation

Toshimitsu Ueki; Masahiko Sumi; Keijiro Sato; Ikuo Shimizu; Daigo Akahane; Mayumi Ueno; Naoaki Ichikawa; Shinji Nakao; Hikaru Kobayashi

To the Editor: Leukemia relapse following allogeneic stem cell transplantation (allo-SCT) remains a major cause of treatment failure (1, 2). Among treatment options, second allo-SCT appears to increase disease-free survival compared with other interventions (3). The most important factors influencing outcomes of second allo-SCT may be the length of remission after the first transplantation and age (2). While disease status may also be an important factor, the probability of remission by re-induction therapy is generally low for relapsed acute leukemia after allo-SCT (4, 5). Limited data exist on other factors, such as conditioning regimens or use of different donors (2). Reducedintensity conditioning (RIC) regimens are now widely used in umbilical cord blood transplantation (CBT) (6). However, few reports exist on the use of RIC regimens in second allo-SCT with CB to treat relapsed patients after first allo-SCT (7). We report the outcomes of RIC CBT without prior reinduction chemotherapy for 11 consecutive adult patients from 2007 to 2009 at our institution (Table 1). Seven had acute myeloid leukemia (AML) and four had acute lymphoblastic leukemia (ALL). Median duration between first SCT and relapse was 6 months (3–24). All but one underwent conditioning with fludarabine (125 mg ⁄m), L-PAM (80 mg ⁄m), and total-body irradiation (TBI; 4 Gy). To achieve the maximum graft-versus-leukemia effect, a relatively low concentration of continuous tacrolimus was used as graft-versus-host disease (GVHD) prophylaxis (mean concentrations for each 10-d period spanning days 1 to 40 were 8.9, 8.9, 10.2, and 9.8 ng ⁄mL, respectively). Six patients received minimal cytoreductive chemotherapy prior to or during conditioning to control the rapid increase in leukemic cells in peripheral blood. Median duration between relapse to second SCT was 37 d (22–60). Four were in complete remission (CR) at the last follow-up (15–37 months). Except for three patients who died early after the second SCT, eight achieved longer CR after the second SCT than after the first. According to the definitions for pre-engraftment immune reaction (PIR) (8) and hemophagocytic syndrome (HPS) following SCT (9), PIR was observed in all cases and HPS in seven. In 10 cases, prednisolone (median dose, 1 mg ⁄kg, ranging 0.2–6.9) was introduced for a short period immediately following the diagnosis of PIR to avoid HPS, which may correlate with graft failure of CB. Graft failure was observed in three patients, two of whom underwent further CBTs as salvage treatment. Complications included severe infections (bacterial, n = 4; viral, n = 5). Other toxicities greater than grade 2 included mucositis (n = 3), sinusoidal obstruction syndrome (n = 2), and generalized skin pain (n = 2). While high grade acute GVHD (III or IV) was not observed in the four patients maintaining CR, all had chronic GVHD. To the best of our knowledge, the largest studies of second allo-SCTs using CB included seven relapsed adult leukemia patients (10) and 22 pediatric (11) leukemia patients; none of the adults and 10 of the pediatric patients received RIC regimens. Compared with these two studies, the interval from first SCT to relapse in the surviving four patients maintaining CR was extremely short in our cohort; in three of four patients, it was 5 months. Compared with the first SCT, an extremely high incidence of PIR was observed with the second SCT (one case vs. all cases), whereas no difference was seen in the incidence of acute GVHD (grade II–IV) and chronic GVHD. Although the biological mechanisms are unclear, PIR is assumed to reflect alloimmune reaction and is observed frequently in CBTs. (8). While the use of CB and a relatively low tacrolimus concentration may have caused the high incidence of PIR and HPS, PIR may have contributed to the suppression of leukemic cells that remained in the early phase after the RIC regimen. Graft failure was a devastating complication that has recently been reported to be closely correlated with HPS following CBT (9). As we previously reported, two of three patients who suffered from graft failure and sepsis underwent successful salvage therapy with a one-day regimen using CB (12). However, further studies are needed to clarify how PIR and HPS should be controlled. LETTER TO THE EDITOR doi:10.1111/j.1600-0609.2010.01555.x European Journal of Haematology 86 (268–271)


Leukemia & Lymphoma | 2015

Successful treatment with reduced-intensity cord blood transplant in a patient with relapsed refractory hepatosplenic T-cell lymphoma.

Masahiko Sumi; Wataru Takeda; Hiroko Kaiume; Takehiko Kirihara; Taro Kurihara; Keijiro Sato; Toshimitsu Ueki; Yuki Hiroshima; Mayumi Ueno; Naoaki Ichikawa; Hikaru Kobayashi

Hepatosplenic T-cell lymphoma (HSTCL) is a rare form of peripheral T-cell lymphoma, representing 3% of all peripheral T-cell lymphoma subtypes in the United State, 2.3% in Europe and 0.2% in Asia [1]. Patients present with systemic symptoms, fever, abdominal pain, weakness and marked hepatosplenomegaly without lymphadenopathy. HSCTL is associated with an aggressive clinical course, a poor response to conventional chemotherapy and a markedly high mortality rate [2 – 6]. Although studies on allogeneic stem cell transplant (allo-SCT) are limited, several successful cases of allo-SCT in patients with HSCTL have been reported, suggesting that this disease is susceptible to graftversus-lymphoma (GVL) eff ects [7 – 12]. We herein report the successful treatment with reduced-intensity cord blood


Leukemia & Lymphoma | 2017

Second cord blood transplantation and interferon-α maintenance therapy for relapsed Ph+ acute lymphoblastic leukemia with the T315I mutation

Masahiko Sumi; Keijiro Sato; Hiroko Kaiume; Wataru Takeda; Takehiko Kirihara; Toshimitsu Ueki; Yuki Hiroshima; Hikaru Kobayashi

In 2008, we reported a case of Philadelphia chromosomepositive acute lymphoblastic leukemia (PhþALL) with the continued detection of minimal residual disease after allogeneic hematopoietic stem cell transplantation (allo-SCT), for which the patient was treated successfully with imatinib and interferon (IFN)-a.[1] This patient has ongoing molecular complete remission (CR) for more than 10 years. We, herein, report a case of relapsed PhþALL with the T315I mutation after unrelated bone marrow transplant (BMT) in a patient who received second cord blood transplantation (CBT) followed by maintenance therapy with IFN-a and subsequently achieved sustained molecular CR. A 51-year-old woman with fatigue and edema of the right leg was admitted to our hospital in December 2012. Her white blood cell count was 82 10/l (85% lymphoblast cells), blast cells were positive for B-cell markers, a chromosomal analysis revealed the abnormal karyotype 46,XX,del(9)(p?),t(9;22)(q34;q11.2)[13]/46,XX[1], and a realtime quantitative polymerase chain reaction (RT-qPCR) detected p190 BCR-ABL mRNA in bone marrow cells. Using compression ultrasonography, venous thrombosis was diagnosed in the right femoral vein. Based on these findings, the patient was diagnosed with PhþALL complicated with right lower extremity deep vein thrombosis (DVT). Due to the risk of pulmonary thromboembolism, we selected dasatinib (140mg/day) concurrent with prednisolone (PSL: 30mg/day) for induction therapy, together with anticoagulation therapy for DVT. The patient successfully achieved cytogenetic CR and received four courses of alternating hyper-CVAD with high-dose methotrexate and cytarabine, concurrent with dasatinib (100mg/day).[2] After three courses of chemotherapy, BCR-ABL mRNA was undetectable by RT-qPCR. BMT from a two-locus human leukocyte antigen (HLA) allele (A and DR locus)-mismatched unrelated donor was performed in May 2013. The patient’s myeloablative conditioning regimen consisted of cyclophosphamide (120mg/kg) and total body irradiation (TBI: 12 Gy). Tacrolimus (Tac) and short-term methotrexate were used for prophylaxis against graft-versus-host disease (GVHD). On days 33 and 69, a bone marrow examination revealed morphological CR and undetectable BCR-ABL mRNA by a RT-qPCR assay. Grade I GVHD of the skin developed on day 47, but resolved spontaneously. Relapse was confirmed with 42% marrow infiltration of lymphoblasts and RT-qPCR detected BCR-ABL mRNA on day 96. A chromosomal analysis revealed the complex abnormal karyotype 46XX,del(1)(q42),t(4;12)(q31:q13), del(9)(p?),der(9)t(9;22)(q34;q11.2)add(22)(q13),-19,der(22) t(9;22),þmar1 [9]/46XX[11]. A direct sequencing study showed the T315I mutation in the BCR-ABL gene. Tac was discontinued, the patient received hyper-CVAD as reinduction chemotherapy, and successfully achieved morphological CR. Since ponatinib was not approved in Japan at that time, urgent CBT was considered necessary in order to achieve long-term remission in this patient. In October 2013, 133 days after first allo-SCT, the patient underwent CBT after a reduced conditioning regimen with 125mg/m fludarabine, 80mg/m melphalan, and 4Gy TBI. A cord blood graft (HLA; one antigen mismatched in the graft-versus-host direction, two antigens mismatched in the host-versus-graft direction) containing 2.5 10 nucleated cells/kg was used. Tac (continuous infusion, target serum concentration: 15 ng/ml) was used for GVHD prophylaxis. On day 20, the patient successfully achieved undetectable BCR-ABL mRNA by RT-qPCR in a bone marrow specimen. Neutrophil engraftment was achieved on day 25. In order to strengthen the graft-versus-leukemia (GVL) effect, the tapering of Tac was initiated on day 30 and grade I GVHD of the skin, which was diagnosed by skin biopsy, developed on day 37. Tac was discontinued on day 40 and skin GVHD deteriorated to grade II. In an attempt to control acute GVHD, low-dose Tac (continuous infusion, target serum concentration: 4 ng/ml) and PSL (1mg/kg) were started on day 47.


The Japanese journal of clinical hematology | 2016

Gastrointestinal post-transplant lymphoproliferative disorder with rapidly forming characteristic lesions after cord blood transplantation: a report of two cases.

Sato Y; Masahiko Sumi; Toshimitsu Ueki; Hiroko Kaiume; Takehiko Kirihara; Wataru Takeda; Taro Kurihara; Keijiro Sato; Yuki Hiroshima; Tokutake K; Kimura T; Masahide Watanabe; Hikaru Kobayashi

Epstein-Barr virus (EBV)-related post-transplant lymphoproliferative disorder (PTLD) frequently involves the gastrointestinal tract, but the endoscopic characteristics of this condition have not been discussed in detail. We report two cases of EBV-related PTLD involving rapidly forming characteristic lesions. Case 1 was a 60-year-old man with acute myeloid leukemia who underwent cord blood transplantation (CBT) after which he initially achieved complete remission (CR). He developed nausea and vomiting on day 99. Gastrointestinal endoscopy showed no tumor-like lesions in his stomach. However, a second endoscopic evaluation, which was performed 7 days after the first, revealed multiple raised lesions in his stomach, and a histopathological examination of the biopsy specimen resulted in a diagnosis of EBV-related PTLD. Case 2 was a 36-year-old man with acute myeloid leukemia who underwent CBT after achieving his second CR. He suffered nausea and pharyngalgia on day 309. Although the initial gastrointestinal endoscopic examination showed only multiple erosive or small ulcerative lesions, a second endoscopic evaluation, which was performed 10 days after the first, revealed a raised lesion with a central ulcer in the duodenum. Histopathological examination of the biopsy specimen yielded a diagnosis of EBV-related PTLD. Both patients were successfully treated by reducing the dose of immunosuppressive agents and administering rituximab.


The Japanese journal of clinical hematology | 2016

[Discordant lymphoma of duodenal EBV-positive peripheral T-cell lymphoma not otherwise specified and ileal diffuse large B-cell lymphoma].

Taro Kurihara; Masahiko Sumi; Hiroko Kaiume; Wataru Takeda; Takehiko Kirihara; Keijiro Sato; Toshimitsu Ueki; Yuki Hiroshima; Mayumi Ueno; Naoaki Ichikawa; Naoko Asano; Masahide Watanabe; Hikaru Kobayashi

A 79-year-old woman was admitted with a 5-kg weight loss and anorexia. Computed tomography showed diffuse lymphadenopathy, and thickening of the duodenal and ileal walls. The patient then underwent biopsy of these sites. Pathological examination revealed duodenal Epstein-Barr virus (EBV)-positive peripheral T cell lymphoma-not otherwise specified (PTCL-NOS) and EBV-negative ileal diffuse large B-cell lymphoma (DLBCL) to be present simultaneously. Combination chemotherapy including rituximab produced a reduction of the duodenal EBV-positive PTCL-NOS lesion, but had no effect on the EBV-negative ileal DLBCL lesion. Thereafter, new lymphadenopathy, high fever, and lactate dehydrogenase (LD) elevation developed, complicated by pneumonia. The patient died due to rapid deterioration of the lymphoma and pneumonia on day 108 after initiation of treatment. EBV-positive PTCL-NOS is reportedly rare and the prognosis is poor. Moreover, EBV-negative ileal DLBCL was diagnosed simultaneously. This case is considered to have had an extremely rare discordant lymphoma, although the exact etiology of its development remains unknown. We speculate that age-related disorders of the immune system and HCV infection may have been associated with the pathogenic mechanism of lymphomagenesis in this case.


The Japanese journal of clinical hematology | 2016

Early diagnosis and successful treatment of disseminated toxoplasmosis after cord blood transplantation.

Taro Kurihara; Masahiko Sumi; Hiroko Kaiume; Wataru Takeda; Takehiko Kirihara; Keijiro Sato; Toshimitsu Ueki; Yuki Hiroshima; Mayumi Ueno; Naoaki Ichikawa; Kaneko Y; Hikosaka K; Norose K; Hikaru Kobayashi

A 66-year-old woman with refractory angioimmunoblastic T-cell lymphoma underwent cord blood transplantation. Prior to transplantation, a serological test for Toxoplasma gondii-specific IgG antibodies was positive. On day 96, she exhibited fever and dry cough. Chest CT showed diffuse centrilobular ground glass opacities in both lungs. The reactivation of T. gondii was identified by the presence of parasite DNA in peripheral blood and bronchoalveolar lavage fluid. Moreover, brain MRI revealed a space occupying lesion in the right occipital lobe. Therefore, disseminated toxoplasmosis was diagnosed. She received pyrimethamine and sulfadiazine from day 99. The lung and brain lesions both showed improvement but the PCR assay for T. gondii DNA in peripheral blood was positive on day 133. On day 146, she developed blurred vision and reduced visual acuity, and a tentative diagnosis of toxoplasmic retinochoroiditis was made based on ophthalmic examination results. As agranulocytosis developed on day 158, we decided to discontinue pyrimethamine and sulfadiazine and the treatment was thus switched to atovaquone. Moreover, we added spiramycin to atovaquone therapy from day 174, and her ocular condition gradually improved. In general, the prognosis of disseminated toxoplasmosis after hematopoietic stem cell transplantation (HSCT) is extremely poor. However, early diagnosis and treatment may contribute to improvement of the fundamentally dismal prognosis of disseminated toxoplasmosis after HSCT.


The Japanese journal of clinical hematology | 2015

[Chromosomally integrated human herpesvirus-6 requiring differential diagnosis of reactivation after allogeneic hematopoietic stem cell transplantation].

Keijiro Sato; Masahiko Sumi; Toshimitsu Ueki; Hiroko Kaiume; Takehiko Kirihara; Wataru Takeda; Taro Kurihara; Yuki Hiroshima; Mayumi Ueno; Naoaki Ichikawa; Takako Sato; Masao Ogata; Hikaru Kobayashi

Human herpesvirus-6 (HHV-6) is known to cause critical encephalitis, as a central nervous system infection, in some hematopoietic stem cell transplantation (HSCT) recipients. Chromosomally integrated human herpesvirus-6 (CIHHV-6) persistently shows HHV-6 DNA in blood, but this does not necessarily suggest active infection. The true clinical significance in HSCT is not clear. The prevalence of CIHHV-6 in Japan is reportedly 0.21%. We herein report two HSCTs: from a CIHHV-6-positive donor to a negative recipient and from a negative donor to a positive recipient. In the CIHHV-6-positive donor case, the recipients plasma, which had been negative for HHV-6 before HSCT, became positive after transplantation and the level then remained high, although the subject was asymptomatic. In the CIHHV-6-positive recipient case, the patients plasma viral load was high just after transplantation, although the subject was asymptomatic, and the load gradually decreased after engraftment. Antivirals had no effect on the viral load in either case. We should consider CIHHV-6 when the HHV-6 DNA load in blood persists asymptomatically after HSCT, to avoid misdiagnosis of reactivated HHV-6 infection and overuse of antivirals. It is also useful to monitor HHV-6 DNA in blood before HSCT, to distinguish HHV-6 reactivation from CIHHV-6.

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Masahiko Sumi

Tokyo Medical University

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Daigo Akahane

Tokyo Medical University

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