Neutrophil chemiluminescence and superoxide production in patients with rheumatoid arthritis: the effect of zymosan, phorbol myristate acetate and platelet-activating factor.
Previous study demonstrated that platelet activating factor (PAF) was a potent inducer of polymorphonuclear leukocyte (PMN) activation. This study used a luminometer to measure the chemiluminescence (CL) of peripheral blood (PB) PMNs in 15 patients with rheumatoid arthritis (RA). Superoxide production from PB and synovial fluid (SF) PMNs was also determined by inhibiting reduction of ferricytochrome C with superoxide dismutase. Neutrophils obtained from 12 age- and sex-matched healthy subjects (HS) were used as controls. The results showed that PAF at both 1 microM and 10 microM significantly increased neutrophil CL in both RA (1.40 +/- 0.90 mv, 1.87 +/- 1.18 vs control 0.66 +/- 0.18) and HS (1.70 +/- 0.72, 2.22 +/- 1.25 vs control 0.67 +/- 0.13), with no significant difference between the two groups. Both PMA and zymosan also significantly enhanced PMN CL in both RA (41.51 +/- 17.42, 40.0 +/- 26.51) and HS (43.42 +/- 17.28, 39.91 +/- 27.24), and those values were much higher than those of controls or via PAF stimulation, but, again, there was no difference between RA and HS groups. Lipopolysaccharide (LPS)-stimulated mononuclear cell supernatant can induce neutrophil activity, too. Like CL, PAF had a weak effect on the generation of superoxide from PMNs. Neutrophils from seven RA SF stimulated with PMA or PAF showed a significant increase in superoxide production (76.05 +/- 2.14, 2.83 +/- 0.18) and these were higher than in PB of either RA patients (54.35 +/- 12.46, 1.03 +/- 0.74) and HS (55.70 +/- 17.9; 1.08 +/- 1.12) (p less than 0.05). These findings demonstrated the PMNs were more activated in SF than those in PB of RA patients and HS, suggesting some unidentified factors in SF provoked PMNs activation.