Suppression of superoxide generation by normal polymorphonuclear leukocytes preincubated in plasma from patients with Felty's syndrome.

Polymorphonuclear leukocytes (PMN) isolated from patients with Felty's syndrome (FS) generate fewer superoxide anions (O-2) upon stimulation with fmet-leu-phe than PMN from normal controls or patients with rheumatoid arthritis (RA). In this study, plasma samples were obtained from 12 patients with RA and 12 patients with FS. Incubation of normal PMN in plasma from Felty patients resulted in a significant reduction in both the rate and total quantity of O-2 generation when activated with fmet-leu-phe. This was not observed with plasma from RA patients. The capacity of a plasma sample to suppress O-2 generation correlated with plasma IgG-PMN-binding activity (IgG-PBA) and, to a lesser extent, with the content of circulating immune complexes (CIC). These data suggest that IgG-PBA and possibly CIC have a pathogenetic role in both qualitative and quantitative defects in PMN in Felty patients.