Monocyte activation by immune complexes of patients with SLE.

1. IC precipitated by PEG from patients with SLE inhibit in vitro the FcR dependent reaction of normal monocytes with sSRBC, while the C3bR dependent reaction of the cells with sensitized yeast is reduced only by some of them. The monocytes were preincubated with the IC for 30 min at room temperature. 2. When the monocytes were incubated with the IC for 22 hours at 37 degrees C the reaction of FcR with sSRBC increased, while the C3bR dependent reaction did not altered. 3. Simultaneously with the increasing FcR dependent reaction, the secretion of lysosomal beta-glucuronidase of monocytes cultivated with IC is greater than those of the controls.