This patient has Rheumatoid Arthritis in addition to her T-LGL (T-LGL is associated with RA in ~30% of patients) and is treated for it with Abatacept, a CTLA-4/IgG fusion protein that inhibits T-cell activation, proliferation and cytokine production of T lymphocytes. The peripheral blood shows almost only malignant lymphocytes with protrusions and a few light granules.