Allogeneic mesenchymal stromal cell therapy for nonregenerative anemia in a FeLV-infected cat: a case report.

Feline Leukemia Virus (FeLV) induces hematologic abnormalities, including anemia, neutropenia, and thrombocytopenia, primarily through disruption of hematopoiesis. Current treatments for FeLV-induced nonregenerative anemia are limited, and the therapeutic potential of mesenchymal stromal cells (MSCs) in this context remains unexplored. This case report describes a 4-year-old FeLV-infected cat with severe refractory anemia and bone marrow erythroid hypoplasia treated with allogeneic adipose tissue-derived MSCs (AMSCs) via combined intraosseous and intravenous delivery (10 million cells per route, 20 million total). The AMSCs were isolated from a healthy donor, expanded, and characterized prior to administration. One month post-treatment, hematocrit and hemoglobin levels significantly improved, enabling corticosteroid discontinuation within 60 days. The cat remained clinically stable without further therapy for 32 months. This case highlights the potential of MSC therapy as a novel approach for FeLV-associated anemia, demonstrating promising long-term outcomes and warranting further investigation.