T-PLL involving lymph node, peripheral blood, pleural fluid, and bone marrow. Diffuse infiltrate of T-PLL in the cervical lymph node by morphology (A [original magnification ×400, hematoxylin and eosin stain]) and CD8 immunostain (B [original magnification ×400]). T-PLL in the peripheral blood (C [original magnification ×1000, Wright-Giemsa stain]) and pleural fluid (D [original magnification ×1000, Wright-Giemsa stain]). Persistent and diffuse involvement of bone marrow by T-PLL status post–4-week treatment with alemtuzumab by morphology (E [original magnification ×40, hematoxylin and eosin stain]) and CD8 immunostain (F [original magnification ×40]). Addition of JAK inhibitor tofacitinib to alemtuzumab markedly decreased the leukemic cells in a repeat bone marrow biopsy by morphology (G [original magnification ×40, hematoxylin and eosin stain]) and CD8 immunostain (H [original magnification ×40]).