Jak3^KI/KImice develop a CTCL-like CD8⁺lymphoproliferative disorder in vivo. (A) Histogram plots presenting the percent of lymphoid cells populations (B220⁺/IgM⁺, CD4⁺/CD8^– and CD8⁺/CD4^–) in the bone marrow, spleen, thymus, lymph node, and peripheral blood (PB) (7 to 13 mice per group; 6- to 14-month-old mice). Double-negative (DN) (CD4^–/CD8^–) and double-positive (DP) (CD4⁺/CD8⁺) thymocytes are also depicted. (B) Histogram plots showing the mean ± SEM of p-Stat5; p-Stat3, and p-Erk in spleen cells (CD8⁺). P values are indicated (Student t test). (C) Evolution of the CD8⁺ population in PB, BM, SM, Thy, and LN of Jak3^KI/KI over time (4 to 8 mice per group). (D) Representative FACS plots describing the TCRα/β⁺Gr1⁺ and CD62L/CCR7 phenotype of the CD8⁺ population in spleen cells of 8-month-old mice.