Superoxide production in neutrophils of patients with rheumatoid arthritis and Felty's syndrome.

The production of superoxide by N-formylmethionyl-leucyl-phenylalanine activated neutrophils was measured prospectively with a ferricytochrome C reduction assay in 33 normals, 33 patients with rheumatoid arthritis and 9 patients with Felty's syndrome. Both the rate and quantity of superoxide production were significantly lower in patients with Felty's syndrome when compared to the other 2 groups. This finding suggests a possible additional factor in the increased propensity of these patients to develop infections.