Loss of monocyte membrane receptors in patients with SLE.

Following an 80-min cold treatment of monocytes and their subsequent heating at 37 degrees C a part of the Fc and C3 receptors is shed from the cells into the serum-free medium. However, while the reduced expression of cell membrane Fc receptors is regenerated at 37 degrees C in 4-8 hr, that of the C3 receptors is not. Initially, the Fc receptor expression of monocytes for patients with SLE is greater than that of controls and after shedding it increases to the level of controls at 37 degrees C in 4-8 hr. The expression and the regeneration of C3 receptors are equivalent to those of controls. The phagocytic ability of patient monocytes is lower than that of controls and the difference also remains after heat treatment.