Apoptotic cells in peripheral blood and multiple organ injury

To evaluate the roles of apoptotic cells in peripheral blood (PB) on multiple organ injury, five patients with hematopoietic stem cell transplantation (HSCT) and one with refractory anemia were examined. The following findings were confirmed. 1) High-dose alkylating agents were administrated as conditioning regimens to all HSCT patients. 2) Many organs were injured in all cases. 3) Neutrophils accumulated in the capillaries of injured organs, and endothelial cells were extensively injured. 4) Large numbers of apoptotic cells and γH2AX(+) cells were observed in the foci of large cells with hyperchromatic nuclei. 5) Increased numbers of apoptotic cells (6/6), γH2AX(+) cells (6/6), scavenger receptor A positive (SRA(+) ) cells (6/6), and tumor necrosis factor (TNF)-α(+) cells (5/6) were observed in PB smear preparations. 6) Cytokines exceeded the normal levels in most patients. From these findings, apoptotic cells were considered to be produced by the administration of high-dose alkylating agents in HSCT patients, and apoptotic cells and SRA(+) cells in PB were thought to play important roles in the development of multiple organ injury in HSCT and MDS patients.