Dasatinib

Abstract

Large granular lymphocytosis: case report A 66-year-old woman developed large granular lymphocytosis during treatment with dasatinib for chronic myeloid leukaemia. The woman was diagnosed with chronic myeloid leukaemia in 2016. She was initially treated with imatinib and obtained response initially. However, after 12 months, the cytogenetic response had been lost. Therefore, she started receiving dasatinib 100 mg/daily [route not stated]. Following 6 months of dasatinib initiation, her lymphocyte count, which had been normal earlier, was increased. At 18 months of dasatinib therapy, it was increased further with peak counts. She was then admitted to a hospital. Thereafter, a her blood film revealed the lymphocytosis due to an increase of large granular lymphocytes. These were mainly cytologically normal, often with large, prominent granules; however, a minority demonstrated dysplastic features, such as nuclear lobulation. A minor population revealed features resembling those seen in viral infections. A subsequent bone marrow aspirate demonstrated 28% lymphocytes, mainly small lymphocytes, which had less obvious cytoplasmic granules. Peripheral blood immunophenotyping revealed 24% of leucocytes to have the immunophenotype of natural killer cells: CD3–/CD16+/CD56+; most expressed CD2; however, 9% of this population did not. Dasatinib was considered to be the culprit for her large granular lymphocytosis [outcome not stated].