Abstract
Plasma from patients with rheumatoid arthritis shows inhibitory activity towards the random and stimulated movement of human polymorphonuclear leucocytes and peripheral phagocytic monocytes in vitro. The inhibitory activity is heat-labile, not present in plasma from patients with noninflammatory diseases, and appears to exert its inhibitory effects by occupying sites on the cell cell membrane from where it may be removed by washing. It is suggested that this factor(s) is responsible for the diminished accumulation of polymorphonuclear leucocytes into skin chambers with occurs in patients with rheumatoid arthritis.