ACTIN POLYMERIZATION IN NEUTROPHILS OF RHEUMATOID-ARTHRITIS PATIENTS IN RELATION TO TREATMENT WITH NONSTEROIDAL ANTIINFLAMMATORY DRUGS

There is evidence that neutrophil functions such as chemotaxis and oxy gen radical formation are disturbed in rheumatoid arthritis (RA). Medi cation might also influence these functions. Cyclic formation and depo lymerisation of actin microfilaments is crucial in cell motility, but this phenomenon has not been studied in RA. The aim of this study was to investigate basal and dynamic (formyl-methionyl-leucyl-phenylalanin e (fMLP)-induced) neutrophil actin polymerisation in ten RA patients ( a) during therapy with non-steroidal anti-inflammatory drugs (NSAIDS) and (b) after stopping NSAIDS. The results were compared with those of ten age-matched controls. Basal F-actin content in RA patients with N SAIDS was significantly lower than in RA patients without NSAIDS and c ontrols: 35.5 (25.0-49.0), 50.5 (27.0-75.0) and 52.5 (32.0-85.0), resp ectively. Conversely, upon stimulation with fMLP, the actin polymerisa tion curve of RA patients with NSAIDS was higher than for RA patients without NSAIDS and controls. These results suggest that, in RA, the ef fects of NSAIDS on neutrophil functions might be related to changes in the-actin polymerisation-depolymerisation cycle. (C) 1997 Elsevier Sc ience B.V.