Effect of three Japanese kampo medicines on platelet activation by monoclonal anti-platelet membrane glycoprotein antibodies.

We studied the effect of three Japanese kampo medicines on platelet activation by an anti-CD9 monoclonal antibody (NNKY1-19) and an anti-human Fc gamma receptor II monoclonal antibody (NNKY3-2). Sho-saiko-to (TJ-9) and Sairei-to (TJ-114) partially suppressed platelet aggregation induced by NNKY1-19, while Juzen-taiho-to (TJ-48) suppressed aggregation induced by NNKY3-2. TJ-9 and TJ-114 also suppressed collagen-induced aggregation, but TJ-48 did not. Flow cytometry showed that the three medicines did not affect antibody binding to the platelets. Thus, all three kampo medicines suppressed platelet activation by anti-platelet glycoprotein antibodies without inhibiting antibody binding.