Lymphoid and Myeloid Proliferations After Chimeric Antigen Receptor (CAR) T-Cell Therapy: The Pathologist's
Jiehao Zhou1, Katalin Kelemen1
1Department of Laboratory Medicine and Pathology, Mayo Clinic, Phoenix, AZ 85054, USA.
International Journal of Molecular Sciences
|September 13, 2025
Summary
CAR T-cell therapy shows promise for blood cancers, but can cause under-recognized hematolymphoid issues. Pathologists are crucial for diagnosing these post-treatment abnormalities.
Area of Science:
- Hematology
- Oncology
- Immunology
Background:
- Chimeric antigen receptor (CAR) T-cell therapy has revolutionized treatment for B-lymphoblastic leukemia, B-cell lymphoma, and multiple myeloma.
- The range of hematolymphoid abnormalities following CAR T-cell therapy is expanding but often under-recognized.
Purpose of the Study:
- To review the clinical and pathological findings of common hematolymphoid proliferations after CAR T-cell therapy.
- To discuss the pathomechanisms and clinical significance of these post-treatment abnormalities.
Main Methods:
- Literature review of clinical and pathological findings.
- Case illustrations of common hematolymphoid proliferations.
- Discussion of CAR T-cell dynamics (distribution, expansion, contraction, persistence).
Main Results:
- CAR T-cell expansion phase can cause transient lymphocytosis.
- Delayed CAR T-cell contraction may lead to hemophagocytic lymphohistiocytosis-like syndrome.
- Immune effector cell-associated enterocolitis and secondary myeloid malignancies are observed post-infusion.
Conclusions:
- Pathologists play a vital role in identifying and characterizing post-CAR T-cell hematolymphoid proliferations.
- Accurate diagnosis is essential for clinical decision-making in patients receiving CAR T-cell therapy.
- Distinguishing these conditions from infections and neoplasms is critical.
