Five Chinese Pediatric Patients with Leukemias Possibly Arising from Immature Natural Killer Cells: Clinical Features and Courses

Leukemias arising from immature nature killer (NK) cells have been proposed as distinct entities and are rare. Treatment and prognosis of these diseases are controversial, and data on children are limited. According to the literature, one of these distinct leukemias may be myeloid/NK cell precursor acute leukemia (MNKPL), with the blasts being cytochemically myeloperoxidase negative (MPO−) and phenotypically CD56+CD3−CD7+CD34+ and myeloid antigens+. The other may be myeloid/NK cell acute leukemia (MNKL), in which the blasts were cytochemically MPOdim and phenotypically CD56+CD16−CD3−CD33+HLA-DR−. Between 2005 and 2008, 4 MNKPL and 1 MNKL children aged 1.3 to 12.5 years were encountered in the First Affiliated Hospital of Sun Yat-Sen University. In those with MNKPL, remarkable extramedullary involvement usually occurring in adults was not observed; however, myelofibrosis was found in 2 children. The child with MNKL abandoned treatment. Those with MNKPL were treated with a protocol designed for childhood hi...