The effect of rifamycin SV on neutrophil functions in patients with rheumatoid arthritis.

The chemotaxis, phagocytic capacity and reducing activity of neutrophils derived from peripheral blood of patients with rheumatoid arthritis (RA) did not differ from those of control. However, some significant differences between neutrophils from rheumatic and healthy subjects emerged in the presence of rifamycin SV. The chemotactic response of neutrophils from patients with RA was activated by rifamycin SV, whereas cells from controls did not orient their locomotion towards the drug. Moreover, incubation of RA patient's cells with rifamycin SV in vitro depressed phagocytic and reducing activities; the same treatment on normal cells failed to alter these functions. A correlation between improvement of clinical symptoms after treatment of RA by local infiltration with rifamycin SV, observed by others, and the impairment of phagocytosis and NBT reduction, here described, was suggested.