Neutrophil enzyme activities in rheumatoid inflammation

This study analyzed the neutrophils and sera of patients with rheumatoid arthritis and of normal controls. No significant differences were found in the activities of the granular enzymes beta-glucuronidase and lysozyme or the cytoplasmic enzyme lactic dehydrogenase (LDH). Normal neutrophils were found to release significant (P less than 0.05) amounts of the granular enzymes, but not of LDH in response to immunoglobulin G aggregates. There was no difference in the percent release exhibited by rheumatoid versus control neutrophils. Studies delineating the effects of rheumatoid factor sera and normal sera on aggregate-induced enzyme release revealed a significant negative correlation between the amount of rheumatoid factor in the sera and the percent release of beta-glucuronidase and lysozyme but not of LDH. These studies thus demonstrate no abnormalities in rheumatoid neutrophil or rheumatoid serum enzyme activities or in neutrophil response to immunoglobulin G aggregates. They suggest, however, that rheumatoid factor may partially inhibit the release of lysosomal enzymes, thus suppressing this important component of the rheumatoid inflammatory process.