The Percentage of Monocytes among “Mononuclear” Cell Fractions Obtained from Normal Human Blood

Abstract

Human peripheral blood “mononuclear” cell fractions obtained by Ficoll-Hypaque centrifugation contained 44% of cells able to phagocytose latex particles. Such cells could be removed magnetically following their incubation with iron filings. Glass wool column filtration was less effective. Very few phagocytic cells were found among cells obtained from patients with CLL. It is concluded that the percentage of monocytes in normal blood is at least twice as high as is commonly recognized on routine smears. These observations point up the need for further purification steps whenever “mononuclear” cells are used in studies concerned with the function of lymphocytes.