Anti-Thymocyte Globulin Effects on White Blood Cell Count
Mechanism and Evidence
- The American Heart Association guidelines list leukocytosis as a known adverse event of corticosteroids, which are often used alongside ATG in treatment protocols 1
- ATG itself can cause various hematological effects, with rabbit ATG specifically associated with leukopenia and thrombocytopenia as common adverse events 1
- ATG can cause a transient increase in white blood cell count before potentially causing leukopenia with continued use 2
Clinical Considerations
- In transplantation protocols, ATG is commonly included in conditioning regimens, with dosing at 10 mg/kg or ATG-F at 40 mg/kg for unrelated donor, cord blood, or haploidentical transplants 3, 4
- These protocols may include monitoring for hematologic effects 5
- The dosing regimen for ATG can range from 0.75-1.5 mg/kg IV daily for rabbit ATG or 10-15 mg/kg daily for equine ATG 1
Important Monitoring Considerations
- Regular complete blood count monitoring is essential during ATG therapy, with potential for initial increase in white blood cell count (leukocytosis) and later decrease (leukopenia) 1, 2
- Other common adverse effects to monitor include gastrointestinal symptoms, myalgias, headache, fever, increased risk of infections, and increased risk of post-transplant lymphoproliferative disorder (PTLD) 1
Clinical Applications
- In myelodysplastic syndromes (MDS), ATG is used as immunosuppressive therapy, particularly in patients with hypoplastic bone marrow, HLA-DR15 positivity, normal cytogenetics, and low-risk disease 6, 7, 8
- For aplastic anemia and MDS, monitoring of blood counts is essential as ATG can affect all blood cell lines, including white blood cells 9