Deformability of peripheral immature and mature neutrophils

Volume and deformability of peripheral immature (bands and metamyelocytes) and mature polymorphonuclear neutrophils (PMN) were studied in venous blood of healthy neonates, children and adults. Metamyelocytes were found only in neonatal blood. Membrane cytoplasm tongues of PMN were aspirated into 2.5-mum (diameter) micropipettes over a period of 1 min. Compared with mature PMN, final tongue lengths of band cells were decreased by 44 to 50% and volumes were increased by 14 to 17%. Neonatal metamyelocytes were more rigid and larger than neonatal band cells. Among mature PMN and band cells in the neonates, children and adults cellular volume and deformation behavior were similar. We conclude that immature neutrophils are markedly less deformable than mature PMN and that these cells may contribute to impaired microcirculation in patients with a marked rise of immature neutrophils in peripheral blood.