The Use of Abatacept for the Treatment of Felty Syndrome in Rheumatoid Arthritis

Felty syndrome is characterized by a triad of rheumatoid arthritis, neutropenia, and splenomegaly that typically occurs in patients with seropositive rheumatoid arthritis. We report a case of an 81-year-old man with a 22-year history of rheumatoid arthritis who developed pancytopenia and neutropenia for one month. An abdominal ultrasound revealed splenomegaly. A bone marrow biopsy excluded large granular lymphocytic leukemia, thus Felty Syndrome was diagnosed. He was treated with a maximum tolerated dose of methotrexate (15 mg once a week) for two months with no improvement in absolute neutrophil count. The patient was given abatacept 1000 mg intravenously every four weeks with improvement in hemoglobin, leukocyte, and platelet counts and absolute neutrophil counts from 0.2 to 2.4 K/µl.