Haematopoietic progenitor cells in an infant who developed pancytopenia following an extensive burn

We observed a 24-month-old infant who developed anaemia, thrombocytopenia and neutropenia while recuperating from an extensive burn. In order to determine the mechanism(s) responsible for the pancytopenia, we quantified marrow-derived haematopoietic progenitor cells, assessed the relative proliferative rate of haematopoietic progenitor cells, and sought the presence of progenitor cell inhibitors. The concentration and relative proliferative rate of pluripotent progenitors (CFU-GEMM) were elevated. No inhibitors of progenitor cells were observed; in fact, the patient's serum contained very high levels of stimulatory activity for CFU-GEMM as well as for granulocyte-macrophage progenitors (CFU-GM). However, the marrow concentration of erythroid progenitors (BFU-E and CFU-E) was diminished. We conclude that the anaemia in this patient was the result of either hypoproduction of differentiated erythroid progenitors or intramyeloid destruction of early erythroid cells. In contrast, the neutropenia was likely to be due to accelerated neutrophil consumption at a rate that exceeded the capacity for increasing neutrophil production.