[A case of rheumatoid arthritis associated with autoimmune hemolytic anemia due to weekly low-dose methotrexate therapy].

A 57-year-old woman was found to have rheumatoid arthritis (RA) in 1996. Treatment with different immunoregulatory agents, including actarit and bucillamine, produced no improvement. Therefore, combined therapy with methotrexate (MTX) (5 mg/week oral) and low-dose prednisolone (PSL) (5 mg/day) was started in April 1997. Sulindac and famotidine were also administered. In August 1997, she was admitted to our hospital because of palpitations and shortness of breath due to severe anemia. Results of laboratory studies were hemoglobin, 2.9 g/dl; reticulocyte count, 225/1000; and haptoglobin, less than 10 mg/dl. The direct and indirect Coombs'tests were positive. A diagnosis of autoimmune hemolytic anemia (AIHA) was made on the basis of the laboratory findings. Treatment with high-dose PSL (50 mg/day) was started, and the anemia improved. The hemoglobin level increased to 6.0 g/dl within the 1st week and to 12.6 g/dl 6 weeks later. We believe that the most likely explanation for this anemia was the low-dose MTX because the anemia appeared soon after treatment was started.