[Effect of rifamycin SV on neutrophil functions in patients with rheumatoid arthritis]

The antibiotic rifamycin SV (RSV) has been successfully used by others on the local treatment of rheumatoid arthritis (R.A.). Since polymorphonuclear leukocytes (PMNL) are involved in the synovial inflammatory process we tested the 'in vitro' effect of RSV on PMNL functions, such as locomotion and phagocytosis. PMNL locomotion was evaluated by using modified Boyden Chamber and phagocytosis was tested by the number of yeast particles ingested and by NBT reduction. The, the functions of PMNL derived from 7 R.A. patients in therapy only with non steroidal anti-inflammatory drugs were compared with those of PMNL from 14 patients with non inflammatory disease (osteoporosis and osteoarthrosis) in the same therapy and with neutrophils from healthy subjects. It was demonstrated that PMNL derived from patients with both R.A. and non inflammatory disease activated their directional locomotion towards RSV, on the contrary, cells from healthy subjects were unresponsive. Moreover, only patients with R.A. showed a defective phagocytic capacity and a depression in NBT reducing activity, when PMNL were treated with RSV. This phenomenon might be correlated with beneficial effect observed after local treatment of R.A. with RSV.