Greetings from the Professor

Welcome to the website of the division of Hematology & Oncology, Department of internal medicine, St. Marianna University School of Medicine. I am Ayako Arai, appointed as the professor of the division as of April 1, 2019. Our department is based on a hill near the Tama river in Miyamae-ku, Kawasaki city. We treat patients with hematologic diseases, educate students and pursue research activities in beautiful natural surroundings full of greenery and blessed with inspirations offered by four seasons.

We are all aware that recent medical advances are remarkable, yet we must admit there are numerous challenges that remain unresolved in the clinical settings. Our goal is to identify solutions to such challenges and deliver them to the patients and the public.

I have specialized in the treatment of hematopoietic tumor and other hematologic diseases using chemotherapy and Hematopoietic Stem Cell Transplantation (HSCT) in my clinical capacity. I also wear a research scientist's hat to analyze the oncogenic mechanisms using a molecular biological methodology. I believe that my mission as a hematology specialist and a medical research scientist is to elucidate the pathogenesis of intractable hematologic diseases and develop a treatment to control them by merging the strengths of clinical medical science and basic medical science. Our team's area of special interest in recent years is to provide care for, elucidate the pathogenesis of, and develop an effective treatment for Chronic Active Epstein-Barr Virus infection (CAEBV) which is classified as an EBV-positive T- or NK-cell neoplasm. It is an intractable disease with hardly any cases reported from the U.S. and western part of Europe. Most cases have been reported from Japan and east Asia to date. We continue to search clues for the following questions: Why does a common virus cause serious diseases in some individuals? Is there any treatment medication to control the disease? Our team is committed to find a cure for all the hematologic diseases including CAEBV.

Our utmost priority is to serve the patients as trusted partners so that they all feel at ease being supported by us. Chemotherapy and transplant which are the standard regimen in the hematology discipline often give a hard time to the patients who are fighting the disease. An interdisciplinary team of physicians, registered nurses, and pharmacists will address their concerns comprehensively so that the treatment is sustainable. We also value QoL (Quality of Life) of the patients. We proactively support patients who receive outpatient chemotherapy and ensure safe and secure treatment. Not only do we brush up our knowledge and skills as technical experts but also hone our human skills so that the patients will have confidence in us.

As we develop undergraduate students and clinical trainees, we help them to become physicians with a heart who can empathize with the patients as they address their needs attentively. Above all I hope to pass on the excitement of studying hematology to them. Our goal is to develop physician scientists who can appropriately extract the essence of the challenge and come to terms with it under any kind of circumstances.

Our class is still small in size and is in a fledgling state. This also means that there is unlimited room for growth. I foresee a series of evidence being launched from the hills of Tama area in Japan to the world.

Ayako Arai MD., PhD.
Professor, Director and Chairperson of the division of Hematology & Oncology, Department of internal medicine, St. Marianna University School of Medicine

How We Provide Care

Care and treatment for hematologic diseases in general is available to both outpatients and inpatients. We try to serve as trusted partners to the patients. A number of experienced care-providing staff support both the outpatient and inpatient care so that patients feel fully informed and feel comfortable to be treated by us.

We participate in JALSG (Japan Adult Leukemia Study Group) to enable ourselves to support the most advanced care for leukemia in Japan. We proactively treat ML (Malignant Lymphoma) and MM (Multiple Myeloma) and participate in clinical trials. Professor Ayako Arai leads the AMED research group that studies Chronic Active Epstein-Barr Virus infection (CAEBV) . Professor Arai is also the principal investigator for the “Phase II Trial investigating the Efficacy and Safety of Ruxolitinib single treatment in patients with CAEBV”, an investigator-initiated study.

Target Disease

  • Hematopoietic tumor (leukemia, lymphoma, myeloma)
    1. Chemotherapy
    2. Hematopoietic stem cell transplantation
    3. Molecular-targeting therapy (including ZEVALIN®)
  • Anemia (aplastic anemia, hereditary hemolytic anemia and acquired autoimmune hemolytic anemia)
  • Hemorrhagic Disorder (Thrombocytopenic Purpura, Hemophilia, other hereditary or acquired Coagulation Disorder)
  • Chronic Active Epstein-Barr Virus infection (CAEBV)

Outpatient Cases in the past 3 years

2016 2017 2018
Acute Leukemia 16 15 11
Hodgkin Lymphoma 3 3 4
Non-Hodgkin Lymphoma 78 62 60
Myeloma, Amyloidosis 16 12 16
MDS Myelodysplastic Syndrome 13 5 18
Chronic Leukemia 6 14 3

The number of Hematopoietic Stem Cell Transplantation in the past 3 years

Autologous Transplantation Allogenic Related Hematopoietic Stem Cell Transplantation Allogenic Unrelated Hematopoietic Stem Cell Transplantation
Peripheral Blood (PB) PB PB Bone Marrow Umbilical Cord Blood
2018 1 1 0 0 0
2017 4 1 0 0 0
2016 2 0 0 0 0

Outpatient Shift Timetable

New Patients / Revisits Specialized outpatient
Mon AM/PM Prof. Arai CAEBV
Tue AM/PM Dr. Sakai
Wed AM/PM Dr. Tomita
Thr AM/PM Dr. Kato
Fri AM/PM Dr. Isobe
Sat AM/PM Dr. Uemura (3)
Dr. Saiki (2,4)

Please click here if you would like to sign up for a booking.

Please click here if you would like to seek a second opinion from us.


Internship, Post Graduate Medical Education (First Half)

Internship is taught based on the original training program of the St. Marianna University School of Medicine. Medical interns will acquire versatile basic skills (general demeanor, procedures and knowledge) applicable in dealing flexibly and in a holistic manner with the diseases and pathology that are encountered in daily practice as they provide care as interns mainly for the inpatients. Interns will also learn cutting edge medical knowledge and evidence-based basic clinical skills by attending a weekly clinical conference, joint inter-campus conference sessions held 2 times a year.

Please click here if you would like to check more information.

Internship, Post Graduate Medical Education (Second Half)

Interns will be assigned to practice as hematology specialists not only in the St. Marianna University Hospitals but also in the hospitals that are related to the University. Interns will acquire professional skills to provide care and are also given the opportunity to actively publish the findings in professional society meetings and scientific journals. They will also receive necessary trainings to qualify as hematology specialists certified by the Japanese Society of Hematology. Licenses for other specialty that can be acquired in our department are shown below.

Please click here if you would like to check more information.

Clinical Conference General Conference (once a week on Wednesdays from 13:00)
The General Conference is followed by the ward round led by the professor.
Clinical Conference Every other Wednesday
Clinical and Pathological Conference Whenever necessary
Joint Conference by Yokohama-city Seibu Hospital The third Thursdays
Protocol Conference Whenever necessary
Specialist Licenses and Degrees available in our department MD, MMSc (Master of Medical Science), Internal Medicine Specialist certified by the Japanese Society of Internal Medicine, General Internal Medicine Specialist certified by the Japanese Society of Internal Medicine, Hematology Specialist certified by the Japanese Society of Hematology, Certified Specialist for Oncology Treatment

Graduate School, Master's Course, PhD course (physicians, scientists, working professionals are eligible as applicants)


Arai Group

What We Do

Our department is the only institute in the world that specializes in the care of and the research for Chronic Active Epstein-Barr Virus infection (CAEBV) in adults. CAEBV is a rare disease of two dimensions: systemic inflammation and neoplastic disease.
The former dimension is characterized by chronic inflammatory symptoms (fever, lymphadenoma, liver dysfunction, vasculitis, and neurological findings) and the latter is characterized by the malignant proliferation of EB virus-infected T- or NK cells identified in the peripheral blood of the patients. Most cases are reported from Japan and other parts of East Asia. Very few cases are reported from the Western world. Initially it was reported that it is a pediatric disorder or disorder frequent among the young adults. But as CAEBV draws more attention, the number of adult cases reported is increasing in recent years. We believe that the Japanese researchers have the obligation to develop a solution for this disease and share the information with the global community of practitioners. Professor Ayako Arai, the group leader, is addressing the challenges of CAEBV as the Principal Investigator of “Phase II Trial to investigate the Efficacy and Safety of JAK1/2 Inhibitor Ruxolitinib in Patients with CAEBV Infection”, an investigator-initiated study funded by the Practical Research Project for Rare/Intractable Diseases at AMED (Japan Agency for Medical Research and Development).

She also participates as a co-researcher in the “Building of the Disease Registry and Biobank of Chronic Active EB Virus Infection and Relative Diseases”, an intractable disease policy research project hosted by the Japanese Ministry of Health, Labor and Welfare. She plays a role in developing guidelines for the treatment and disease registry. She is also engaged in patient advocacy through CAEBV patient organization SHAKE (

In Pursuit of a Better Care

EBV infected T- or NK cells must be identified first to diagnose a patient with CAEBV. This is why it is difficult to identify the disease by general examination. Besides, an effective regimen has not been established yet. A quick and accurate diagnosis method, elucidation of pathogenesis and the development of an effective treatment is urgently required. Our department strives jointly with National Health Center for Child Health and Development and Tokyo Medical and Dental University to provide quick and accurate diagnosis.

In order to elucidate the mechanisms of the disease

We are currently trying to elucidate the pathogenesis of the CAEBV infection and are developing new treatments with the grant extended by AMED (Japan Agency for Medical Research and Development) as part of the basic research efforts. We have been successful in developing the disease model mouse, and clarified the molecular mechanisms of immortalization process and malignant transformation of the EBV-associated T-or NK cells.
We also published a paper on retrospective analysis of the pathogenesis of adult cases in Japan and the outcome of hematopoietic stem cell transplant cases. Details can be found in the research track record of our department. We also started the investigator-initiated study investigating the efficacy and safety of Ruxolitinib in 2019.

Our Mission

CAEBV infection is a serious disease. As there is not any patient in Europe and in the USA, Japanese researchers are obligated to elucidate its pathogenesis. We would like to make use of all the information provided by the patients to develop an efficacious treatment.



  • Ayako Arai
    Ayako Arai
    Personal Profile
  • Naoto Tomita
    Associate professor
    Naoto Tomita
  • Masayuki Kato
    Masayuki Kato
  • Yasushi Isobe
    Yasushi Isobe
  • Yoshinori Suzuki
    Assistant professor
    Yoshinori Suzuki
  • Yu Uemura
    Assistant professor
    Yu Uemura
  • Yusuke Saiki
    Postgraduate student
    Yusuke Saiki
  • Madoka Takimoto
    Part-time Lecturer
    Madoka Takimoto
  • Satoshi Yokoi
    Part-time clinical fellow
    Satoshi Yokoi
Research Technician
Junko Asano
Department Secretary
Natsuko Habuka
Assistant to Professor Ayako Arai
Ayako Komoto

Yokohama-city Seibu Hospital

  • Fumiaki Sano
    Specially appointed associate professor
    Fumiaki Sano
  • Yasuyuki Inoue
    Associate professor
    Yasuyuki Inoue
  • Manabu Matsunawa
    Assistant professor
    Manabu Matsunawa
  • Akiko Uchida
    Assistant professor
    Akiko Uchida