Decreased hydroxyl radical generation from polymorphonuclear leucocytes in the presence of D-penicillamine and thiopronine.

The effect of D-penicillamine (DP) and thiopronine on the generation of reactive oxygen species (ROS) both by stimulated polymorphonuclear leucocytes (PMNs) and in a cell-free, xanthine-xanthine oxidase system was investigated. Both drugs significantly reduced hydroxyl radical (OH.) generation in the PMN system, however, increasing trends of OH. levels were noticed in a cell-free ROS generating system. Although the opposing effects on ROS levels were verified, these two agents showed a similar behaviour presumably due to their structural similarity. The properties of these agents that affect ROS levels may contribute to their beneficial and toxic actions in inflammatory as well as immunoregulatory processes of rheumatoid arthritis (RA).