Evaluation of proliferative disorders in canine bone marrow by use of flowcytometric scatter plots and monoclonal antibodies

The combination of flow cytometric scatterplot analysis and specific monocl onal antibodies was used to evaluate the lineage of cells from six dogs wit h proliferative disorders of bone marrow. Scatterplot analysis was used to identify mature and immature myeloid and erythroid cells. The immunophenoty pe of cells in the immature myeloid gate was determined by labeling cells w ith four monoclonal antibodies. These results were compared to results of c ytologic and cytochemical evaluation. The immunophenotype of a dog with a d iagnosis of myelogenous leukemia was a cluster of differentiation-18 (CD-18 ) positive, CD-14 negative, Thy-1 negative, and a major histocompatibility complex (MHC) class II negative. The immunophenotype of a dog with a diagno sis of myelomonocytic leukemia was CD-18 positive, CD-14 positive, Thy-1 po sitive, and MHC class II positive. Although this phenotype clearly differen tiated myelomonocytic leukemia from myelogenous leukemia, it was similar to the immunophenotype of dogs with a diagnosis of malignant histiocytosis or hemophagocytic syndrome. The immunophenotype of two dogs with myelodysplas tic syndrome was CD-18 positive and CD-14 negative. Results for Thy-1 and M HC class II were variable. As additional lineage-specific monoclonal antibo dies become available, immunophenotyping should become a valuable tool for determination of the lineage of cells in canine myeloproliferative disorder s.