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NK Cell Therapy as Immune Support During Chemotherapy

Published 2026.09.20 7 min read

Hello, I am Dr. Hidenori Shimada of Grand Green Osaka Umekita Clinic in Osaka, Japan.

Standard cancer treatments like chemotherapy and radiation therapy are cornerstones of modern oncology, targeting and destroying cancer cells. However, these powerful treatments can also affect healthy cells, including the immune cells that protect your body. For patients undergoing these treatments, maintaining a robust immune system is a common concern. This article explores the role of adjunctive NK cell therapy as a potential option to support the body's natural defenses during cancer treatment.

The Challenge: Immune Suppression During Cancer Treatment

Chemotherapy drugs are designed to eliminate rapidly dividing cells, a hallmark of cancer. Unfortunately, many of the body's healthy cells also divide quickly, including immune cells like lymphocytes. This can lead to a temporary decrease in immune function, making a person more susceptible to infections and potentially impacting their overall well-being during a critical treatment period. Similarly, radiation therapy, while targeted, can also have an effect on circulating immune cells.

This suppression of the immune system is a well-understood side effect of many standard cancer therapies. Patients and their doctors often focus on managing these side effects to ensure treatment can continue as planned. This has led to growing interest in supportive, or adjunctive, therapies that aim to bolster the immune system without interfering with the primary cancer treatment.

What is Adjunctive NK Cell Therapy?

Natural Killer (NK) cells are a specialized type of white blood cell and a key part of the body's innate immune system. Their primary role is to patrol the body and eliminate abnormal cells, such as cancer cells or virus-infected cells, without prior sensitization. They are the immune system's first line of defense.

NK cell therapy is a form of immunotherapy that utilizes a patient's own (autologous) NK cells. The process typically involves:

Blood Collection: A standard blood draw is performed to collect a sample of the patient's blood, which contains their NK cells.
Activation and Expansion: The collected NK cells are sent to a specialized cell processing facility. There, they are isolated, activated, and cultured in a controlled environment to significantly increase their number and enhance their cell-killing activity.
Reinfusion: The expanded and activated NK cells are then returned to the patient's body through a simple intravenous (IV) drip.

The goal of this therapy is not to replace standard treatments like chemotherapy or radiation, but to complement them. By reintroducing a larger, more active population of the patient's own NK cells, the therapy aims to reinforce the immune system at a time when it may be weakened.

The Role of NK Cells as a Supportive Immunotherapy

The rationale for using NK cell therapy alongside conventional treatments is based on the fundamental role of the immune system in managing cancer. A healthy immune system constantly performs “immune surveillance,” identifying and destroying abnormal cells before they can multiply. Cancer treatments, while necessary, can disrupt this crucial function.

Adjunctive NK cell therapy seeks to support this surveillance mechanism. Because the therapy uses the patient's own cells, the risk of rejection is considered low. It is a treatment with a light physical burden, involving only a blood draw and an IV infusion, which allows patients to continue their daily lives without hospitalization. Research continues to explore how different immunotherapies, including those involving NK cells, can be integrated with chemotherapy, radiation, and antibody drugs to support anti-tumor responses.

In Japan, treatments like NK cell therapy are provided under the regulations of the Act on the Safety of Regenerative Medicine. This ensures that cell processing and treatment administration are performed according to national standards for safety management. It is important to note that this therapy is considered a private medical service and is not covered by public health insurance.

What to Discuss with Your Doctor

Making informed decisions about your health is paramount. If you are considering adjunctive NK cell therapy, a thorough consultation with a physician is essential. Here are some key points to discuss:

Individual Suitability: Is this therapy appropriate for my specific type of cancer, stage, and overall health condition?
Treatment Goals: What is the realistic objective of this therapy in my case? Is it for supporting immune function during chemotherapy, or for other purposes like preventing recurrence?
Process and Schedule: What does the treatment schedule look like, and how does it coordinate with my existing standard treatment plan?
Risks and Side Effects: While generally considered to have few serious side effects, what are the potential risks? Temporary fever or fatigue may occur after the infusion.
Costs and Duration: As a non-insured treatment, what are the associated costs, number of sessions, and expected duration of the therapy?

Exploring Your Options in Osaka, Japan

For those seeking information about adjunctive cancer treatments in Japan, Grand Green Osaka Umekita Clinic provides consultations on cell therapies, including NK cell therapy. Our team can help you understand the process and determine if it aligns with your health goals and current treatment regimen. A physician's assessment is required to determine eligibility and create a suitable plan.

We encourage you to gather comprehensive information to make a well-informed decision in consultation with healthcare professionals. For more details on the features, process, and considerations of this treatment, please see our dedicated information page.

Learn more about NK Cell Therapy at our clinic.

Summary: A Supportive, Not Alternative, Approach

Undergoing chemotherapy or radiation is a demanding journey. Supporting the body's immune system during this time is a valid concern for many patients. Adjunctive NK cell therapy represents one potential option aimed at reinforcing the body's natural defenses. It is not a cure for cancer nor a replacement for standard medical care. Instead, it is offered as a complementary therapy that works alongside conventional treatments. The decision to pursue any adjunctive therapy should always be made after a detailed discussion with a qualified physician who can assess your unique medical situation.

Adjunctive NK Cell Therapy Flow

11. Blood CollectionCollect patient's own NK cells
22. Cell ExpansionActivate and grow NK cells in a lab
33. IV ReinfusionReturn enhanced cells to the body
44. Immune SupportAims to reinforce natural defenses

This is a conceptual diagram to summarize the main points of the article

Learn more about NK Cell Therapy

References

Supervising Physician

Director, Medical Corporation Shimada Clinic
Head of Clinical Practice, Grand Green Osaka Umekita Clinic

Hidenori Shimada

Graduated from the University of Tokushima Faculty of Medicine in 2005. After his initial residency, he obtained U.S. medical certification (ECFMG) and trained as a sub-intern in general surgery at the University of Washington. After completing the doctoral program at Kyoto University Graduate School of Medicine and working as a researcher at the Center for iPS Cell Research and Application (CiRA), Kyoto University, he founded Shimada Clinic in 2013. At Grand Green Osaka Umekita Clinic (https://umekitaclinic.org), he is engaged in a wide range of care, from internal medicine and pediatrics to cell therapy and aesthetic medicine.

* The physician supervision of this article covers its academic content only and does not constitute a recommendation of any specific treatment or product.

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