Arizona Center on Aging Co-Director Dr. Nikolich-Zugich Participates in Study of Radiation and Aging

This study will help us understand how the immune system ages and will allow us to improve the care of older adults...

Janko Nikolich-Zugich, MD, PhD, co-director of the Arizona Center on Aging at the University of Arizona College of Medicine in Tucson, is joining a team of nine experts in Japan and the United States who will study the effect of radiation and aging on the human immune system.

The National Institute of Allergy and Infectious Diseases (NIAID), part of the National Institutes of Health (NIH), recently awarded nearly $9.7 million over five years to the Radiation Effects Research Foundation (RERF) in Japan for the study. For the first time, experts in both the United States and Japan systematically will analyze biological samples from the unique population of elderly Japanese atomic bomb survivors to better understand the health consequences of exposure to ionizing radiation on the natural aging process.

(Dr. Nikolich-Zugich also is chairman of the UA College of Medicine Department of Immunobiology; Elizabeth Bowman Professor in Medical Research; professor of medicine; professor with the Department of Nutrition Sciences in the UA College of Agriculture and Life Sciences; and a member of the UA BIO5 Institute.)

As people grow older, their immune systems also age, leading to a gradual decline in the body’s ability to fight infections, respond to vaccinations and prevent the development of cancer. The aging of the immune system, known as immunosenescence, is a major contributing factor to disease and death among older persons. Radiation exposure appears to accelerate immunosenescence, although the molecular events that cause immunosenescence are not well understood.
“This study will help us understand how the immune system ages and will allow us to improve the care of older adults, as well as of the survivors of deliberate (radiotherapy) or accidental exposure to irradiation,” says Dr. Nikolich-Zugich.

The researchers will study the unique group of atomic bomb survivors who were exposed to varying levels of radiation in 1945. Using state-of-the-art technology, investigators will analyze blood samples from survivors to determine how radiation exposure alters the normal age-related decline of the immune system and identify the cellular and molecular changes that occur. They also will determine how the observed immune changes are related to disease and infection. One goal is to understand how aging and exposure to ionizing radiation affect a person’s response to vaccination.

The information gained from the study will benefit the general public as well as patients who undergo radiation treatment for cancer, and also people exposed to radiation in industrial accidents or even in terrorist attacks. “This collaboration complements NIAID’s program to develop medical countermeasures against radiological and nuclear threats,” says Daniel Rotrosen, MD, director of NIAID’s Division of Allergy, Immunology and Transplantation, which oversees this award.

Leading the team will be Yoichiro Kosunoki, PhD, Kei Nakachi, PhD, and Tomonori Hayashi, PhD, of the Department of Radiobiology/Molecular Epidemiology at RERF. In addition to Dr. Nikolich-Zugich, team members include (from Japan) Yoko Hirabayashi, MD, National Institute of Health Sciences, Tokyo; Atsushi Iwama, MD, Chiba University; Shigeo Koyasu, PhD, Keio University, Tokyo; and Koji Yasutomo, MD, PhD, University of Tokushima; and (from the United States) Nancy Manley, PhD, University of Georgia, Athens; Gregory Sempowski, PhD, Duke University, Durham, N.C.; Marcel van den Brink, MD, PhD, Memorial Sloan-Kettering Cancer Center, New York City; and Nan-ping Weng, MD, PhD, National Institute on Aging, National Institutes of Health, Baltimore, Md.


Radiation Effects Research Foundation (RERF), formerly known as the Atomic Bomb Casualty Commission, is a cooperative Japan-U.S. scientific organization that has been in existence for 62 years and is based in Hiroshima and Nagasaki, Japan. The foundation performs research to evaluate and document the long-term health effects of acute radiation exposure on survivors of the atomic bomb. For more information about RERF, visit

The National Institute of Allergy and Infectious Diseases (NIAID) conducts and supports research – at the National Institutes of Health (NIH), throughout the United States, and worldwide – to study the causes of infectious and immune-mediated diseases, and to develop better means of preventing, diagnosing and treating these illnesses. News releases, fact sheets and other NIAID-related materials are available on the NIAID Web site at

The National Institute on Aging (NIA), part of the NIH, leads the federal government effort conducting and supporting research on the biomedical, social and behavioral issues of older people. For more information on aging-related research and the NIA, go to

The National Institutes of Health (NIH)—The Nation's Medical Research Agency—includes 27 Institutes and Centers and is a component of the U. S. Department of Health and Human Services. It is the primary federal agency for conducting and supporting basic, clinical and translational medical research, and it investigates the causes, treatments and cures for both common and rare diseases. For more information about NIH and its programs, visit