Allogeneic hematopoietic cell transplantation in a dog with acute large granular lymphocytic leukemia

Abstract

Case description: A 3-year-old 10-kg (22-lb) neutered male Cavalier King Charles Spaniel was referred because of an episode of acute vomiting and diarrhea.

Clinical findings: On physical examination, mild splenomegaly and prominent submandibular and popliteal lymph nodes were detected. Complete blood cell count revealed a high WBC count, characterized by a moderate lymphocytosis with 62% unclassified cells and severe thrombocytopenia with macroplatelets. On cytologic evaluation, the unclassified cells were described as large, neoplastic lymphoid cells containing a large nucleus with lacy chromatin and a large amount of blue vacuolated cytoplasm containing sparse, very fine azurophilic granules. A diagnosis of acute large granular lymphocytic leukemia of splenic origin was made.

Treatment and outcome: Following induction chemotherapy, the affected dog underwent allogeneic hematopoietic cell transplantation with dog leukocyte antigen-matched CD34+ cells harvested from a sibling of the same litter. Chimerism analysis revealed full donor engraftment within 2 weeks after transplantation that remained stable for at least 2 years, with the dog remaining apparently healthy at home.

Clinical relevance: Acute leukemias in dogs are rapidly fatal diseases. If an appropriate donor can be located, allogeneic hematopoietic cell transplantation may offer a feasible treatment, although peripheral blood CD34+ cell harvesting requires the availability of cell separator machines and management of graft-versus-host disease with immunosuppressive agents.