Influence of carbidopa, an aromatic amino acid decarboxylase inhibitor, on the development of autoimmune hemolytic anemia in NZB mice.

Causal relationships of carbidopa and its related drugs on the development of spontaneous autoimmune hemolytic anemia (AIHA) in NZB mice were studied, and the following results were obtained: 1) Long term treatment with carbidopa (3 mg/kg/day) and levodopa (30 mg/kg/day) neither accelerated nor suppressed the development of spontaneous AIHA in NZB mice. 2) In mice treated with carbidopa/levodopa (3/30 mg/kg/day), microhematocrit levels were lower than those in the control mice on and after 20 weeks of age and showed a significant decrease at 66 weeks of age (P less than 0.05). The average anti-RBC antibody titers reached the maximum level 8 weeks earlier than the control group. 3) Microhematocrit levels in the alpha-methyldopa (60 mg/kg/day)-treated group were higher than those in the control group, and at 66 weeks of age, they were decreased below that in the control group. The elevation of anti-RBC antibody titers was slower than that in the control group. As the reason for the weak effectiveness of alpha-methyldopa on the incidence of AIHA, it might be considered that the dosage employed was not sufficiently high enough and/or it may be due to the species difference between man and animals. Further studies are necessary in order to draw a conclusion on the AIHA-inducing ability of carbidopa.