Ultrastructural changes of neutrophils following IL-2 treatment in vivo.

An ultrastructural analysis of peripheral blood cells of cancer patients following recombinant interleukin-2 (rIL-2) treatment at high doses (rIL-2, 18 x 10(6) I.U./m2/day) has been performed. Characteristic patterns of intense phagocytosis (neutrophils with large vaculoes containing electron-dense bodies) were observed in granulocytes of the treated patients with respect to the basal situation. These characteristics were particularly evident in the advanced stages of the therapy (24 and 48 h). The state of neutrophil activation was sometimes accompanied by the appearance of a close net of cell membranes, probably derived from lamellopodia.