GSTM1 and Felty syndrome: Both MTX and LEF can improve joint and vascular inflammation in patients with Felty syndrome.[4,26] Sulfasalazine suppositories can directly inhibit or even kill the activated immunoactive cells, and they have positive impacts on pain relief and disease control.[3] Some clinical trial results have shown that cyclophosphamide effectively treats Felty syndrome, but the resulting reduction in granulocytes limits its use.[15] However, the significant reductions in WBC, Hb, and BPC limit the use of immunosuppressive agents.