Study on the in vitro Rieder Cell

Abstract

Light and electron microscopic studies were performed on the in vitro Rieder cells from patients with chronic lymphocytic leukaemia (CLL) and acute prornyelocytic leukaemia (APL). Light microscopically, it was found that Rieder cells were increased at essentially the same rate as in the EDTA and sodium citrate treated blood, when the control samples (coagulated blood and defibrinated blood) were simply left at room temperature as well as at 37° C. Vincristine had a suppressive effect on the Rieder cell formation in CLL but did not reduce the number of APL‐cells that had lobulated and separated nuclei. Electron microscopically, a bundle of many microtubules was found to surround the nuclear constriction of the in vitro Rieder cells in CLL, whereas the corresponding bundle consisted of only microfilaments in the in vivo Rieder cells of APL. Vincristine induced disappearance of the microtubules of Rieder cells and formation of many crystals in the cytoplasm of leukaemic cells of CLL and APL but did not affect the microfilaments in the cells of APL.