Chemotactic behaviour of peripheral and synovial neutrophils during rifamycin SV therapy in rheumatoid arthritis.

The effect exerted by rifamycin SV, used intra-articularly in the treatment of rheumatoid arthritis, on polymorph function was studied. Random and directional locomotion of synovial fluid neutrophils was compared with that of peripheral blood cells in 10 patients followed up during 5 drug applications. PMNs from the two sources were characterized by different responsiveness to this pharmacological agent: blood cells activated chemotaxis in a dose-response way during rifamycin therapy, whereas synovial polymorphs did not modify their locomotor behaviour. It is proposed that the presence of immune complexes and/or factors produced by cell-cell interactions in the articular space may change the synovial neutrophil response to stimuli.