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Is My Child at Risk for Infection After a Bone Marrow Transplant?

Jun 23, 2020
Little girl wearing face mask

The immune system is responsible for recognizing and eliminating germs from the body.

White blood cells are the infection fighting cells in our blood. They originate from blood-forming stem cells, which live in the bone and ultimately mature into white blood cells, red cells, and platelets that circulate in the blood stream.

A bone marrow transplant involves taking those stem cells from a donor and putting them into a patient. The patient usually has received chemotherapy or radiation before receiving the donor stem cells.

What Happens After the Patient Is Infused With Stem Cells?

After infusion, donor stem cells migrate to the bone marrow of the patient and eventually start to divide into the circulating blood cells. This process is called engraftment and varies widely based upon the source of the stem cells. The first cell to engraft are the white blood cells, followed by the red cells, then the platelets.

However, several types of white blood cells make up the human immune system. Phagocytes kill germs by gobbling the germ up and then releasing certain chemicals that destroy it. Phagocytes are part of our innate immune system, the first line of defense against infection.

The adaptive immune system is the second line of defense against infection. These cells are more advanced than phagocytes in that they remember what they encountered. For example, lymphocytes are responsible for maintaining memory against vaccines, so that we are protected against these germs for our lifetime.

Lymphocytes take longer to engraft and to mature in their function than phagocytes. As a result, the bone marrow transplant patient has an immature immune system for many weeks and even months until the white blood cells recover in adequate numbers and function normally.

The process of restoring donor immunity in the transplant recipient is called immune reconstitution. Many factors affect immune reconstitution. Overall, immune recovery is a delicate process that often gets delayed by complications associated with transplant - like infection.

What Other Factors Predispose My Child to Infection After Bone Marrow Transplant?

Other factors that increase risk for infection include having a central venous catheter (used to draw blood and receive medications during treatment) and receiving certain medications that suppress the immune system. These medications include chemotherapies and newer biologic agents that modify the immune response either by eliminating certain cells or changing how they function. See “Immunodeficiency and Infection: Who is at Risk?” for more information.

Can Infections Be Prevented After Bone Marrow Transplant Using Antibiotics?

Yes, certain infections can be prevented by giving medications that prevent some bacteria, fungi and viruses. However, no medication is 100% effective; and the best defense against infection is a normal, fully-functioning immune system.

What Happens When My Child Is Suspected of Having an Infection After Receiving a Bone Marrow Transplant?

Transplant patients are at high risk for potentially life-threatening infections, so the transplant team monitors for certain infections, especially viruses, through blood work. Other infections are suspected when a transplant patient has a fever. At that time, your child will be evaluated by a health care provider and undergo blood work and may even have certain imaging performed, like x-rays.

When an infection is suspected, your child will receive medications that treat the type of infection that is suspected. Once an infection is confirmed, your child will receive medication specific to the type of infection. They may need to have repeat testing, blood work or imaging, to make sure the infection has been treated.

At Nationwide Children's Hospital, the Host Defense Program is a group of infectious disease doctors with expertise in diagnosing, preventing, and treating infections in bone marrow transplant patients. These physicians work closely with the bone marrow transplant team in providing care to ensure best outcomes in bone marrow transplant recipients. They are also involved prior to transplant and after transplant to address infection-related issues.

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Jeffery Auletta
Jeffery Auletta, MD
Hematology, Oncology and BMT

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