A 47-year-old female with a history of anti-cyclic citrullinated peptide (anti-CCP) and rheumatoid factor seropositive rheumatoid arthritis was sent to an outpatient clinic with a diagnosis of neutropenia. She has not had any recent infections. Her rheumatoid arthritis mainly affects her hands and has been under control with etanercept therapy. During her physical exam, it was noticed that her spleen was 4 cm below the costal margin, and she had bilateral swelling of the MCP joints; all other findings were normal.
Her CBC is as follows: WBC: 8900/µL Absolute neutrophil count: 451/µL Absolute lymphocyte count: 7900/µL Hgb: 10.5 g/dl MCV: 89 fL PLT: 325k/µL On viewing her peripheral smear, more than 60 percent of WBCs are similar to the cells seen in the cover image. Flow cytometry of the peripheral blood showed CD3 + CD4 - CD8 + CD57 + TCRαβ + immunophenotype of the lymphocytes. TCR-γ…
