Understanding Antithymocyte Globulin (ATG) Treatment for Myelodysplastic Syndromes

Myelodysplastic syndromes (MDS) are a group of blood disorders that develop when the bone marrow doesn't produce enough healthy blood cells. This happens because of problems with the stem cells in the bone marrow, which are responsible for creating new blood cells.

For some patients with lower-risk MDS, a treatment called Antithymocyte globulin (ATG) might be an option. ATG has been used since the early 1990s to suppress the immune system, which can help the bone marrow recover and start producing healthy blood cells again.

How Does ATG Work?

In some MDS patients, the immune system mistakenly attacks the bone marrow stem cells. ATG is an intravenous therapy that helps by targeting and reducing these attacking immune cells (specifically T-cells). This allows the bone marrow to regenerate and produce more healthy blood cells, potentially reducing or even eliminating the need for blood transfusions.

Who Might Benefit from ATG Treatment?

ATG is typically considered for patients with lower-risk MDS who are under 60 years old and have high levels of a hormone called erythropoietin, which stimulates red blood cell production.

Doctors may recommend ATG alone or in combination with other medications such as cyclosporine, prednisone, tacrolimus, or etanercept. Factors that might make someone a good candidate for ATG include:

• Lower-risk MDS
• Age under 60
• High erythropoietin levels
• Hypocellular marrow (low number of cells in the bone marrow)
• Specific immune system characteristics (for example, high levels of CD8 memory T cells)

ATG in Bone Marrow Transplants

ATG is also used in patients undergoing allogeneic hematopoietic stem cell transplantation (bone marrow transplant). In this procedure, a patient receives healthy stem cells from a donor. ATG helps prevent the donor's immune cells from attacking the recipient's body (graft-versus-host disease), although in the US cyclophosphamide is more commonly used for this indication.

Potential Side Effects of ATG

While ATG can be beneficial, it's important to be aware of potential side effects, which can include:

• Increased risk of infections
• Nausea and vomiting
• Skin reactions (hives or urticaria)
• Diarrhea
• Dizziness
• Headache
• Allergic reactions

Important Points to Remember

• ATG is an immunosuppressive therapy that can be effective for some patients with lower-risk MDS.
• It works by suppressing the immune system, allowing the bone marrow to recover and produce healthy blood cells.
• ATG might also be used to prevent graft-versus-host disease in bone marrow transplant recipients.
• Like all treatments, ATG can cause side effects, and it's essential to discuss the risks and benefits with your doctor.

Continue learning about MDS treatment with HealthTree University: discover how to prepare for treatment, navigate life post-treatment, and understand what a bone marrow transplant is. Explore all the videos for free in the link below: 

HealthTree University for MDS: Treatment Options

Sources: 

• Myelodysplastic Neoplasms (MDS): The Current and Future Treatment Landscape
• NCCN guidelines for patients – Myelodysplastic syndromes
• Immunosuppressive Therapy
• ATG or post-transplant cyclophosphamide to prevent GVHD in matched unrelated stem cell transplantation?