Tocilizumab treatment in Felty's syndrome.

Felty's syndrome (FS) is a deforming disease, characterized by the triad of rheumatoid arthritis (RA), neutropenia, and splenomegaly. Currently, FS patients are treated mainly with immunosuppressants, such as methotrexate and glucocorticoids, which however are not suitable to some patients and may cause severe side effects. Here we report a clinical FS case that was treated with Tocilizumab (TCZ) successfully. The patient had symmetrical swelling and pain of multiple joints, deformity of elbow joints with obvious morning stiffness. Joint color Doppler ultrasound showed synovial hyperplasia and bone erosion of wrist and proximal interphalangeal joints and CT scan suggested splenomegaly. Further examination showed neutropenia and anemia, a high titer of anti-cyclic citrullinated peptide antibody, rheumatoid factor and anti-nuclear antibodies, positive p-ANCA, and elevated IgA and IgG. After treating with TCZ, the patient has been relieved of clinical symptoms. His spleen has recovered to normal size. The absolute neutrophil count (ANC) tended to be stable, and joint erosion did not deteriorate. We have reviewed the literatures on FS treatment with biological agents and found only a few reports using TNF-α antagonist and rituximab treating FS, but none with TCZ. So, it is the first time to report a successful FS case treated with TCZ. This case suggests that the TCZ may be a new choice for FS treatment, under the condition of closely monitoring the ANC.