Clinically, some traditional Chinese herbal medicines have been thought to be effective in treating rheumatic diseases such as rheumatoid arthritis and systemic lupus erythematosus. To examine the mechanism by which such herbal remedies might be effective, we investigated the ability of Tripterygium wilfordii Hook-f (TWHf) and tetrandrine (TTD) to affect human immune responsiveness in vitro.
We measured the ability of these agents to affect cytokine secretion from monocytes or T cells, prostaglandin E2 (PGE2) secretion from monocytes, IgG production from B cells, and the phagocytosis of bacteria by neutrophils.
These studies revealed that both TWHf and TTD significantly inhibited interleukin-1 (IL-1), tumor necrosis factor-alpha (TNF-alpha), IL-6, and IL-8 secretion from monocytes, IgG secretion from B cells, and phagocytosis of bacteria by neutrophils; however, only TWHf inhibited IL-2 and IL-4 production from lymphocytes, and PGE2 secretion from monocytes.
TWHf and TTD exert a powerful suppressive effect on human immune responses. This action might account for their therapeutic effectiveness in rheumatic diseases, and might support broader and more rigorous clinical trials.