Virus-Like Particles in Human Leukemic Plasma.

Abstract
Summary Differential and zonal ultracentrifugation followed by brief ether exposure or by isopycnic banding in CsCl, has yielded virus-like particles from the plasma of 8 leukemic patients. In electron microscopic examinations, two morphologically different particles were observed, designated “R” and “Q.” In 18 controls, no “R” particles were found, but in one control “Q”-like particles were observed. The density of the particles is the same in all instances.