Ruxolitinib inhibits PTCL expansion and systemic inflammation in patient-derived PTCL xenograft mouse models. (A) Transplantation scheme for engraftment and in vivo expansion of malignant T cells from a patient with AITL. Firstly, 1 NOG mouse received transplantation IV with 6 × 10⁶ PB cells of a patient with AITL after Ficoll purification. Then, FACS analysis and spectratyping revealed engraftment of the malignant clone, T cells (> 95%) were extracted from the spleen, and 36.1 × 10⁶ hCD45 cells were transplanted IV into 2 secondary recipients. Upon engraftment, isolation and retransplantation was repeated, and 8 recipients received transplantation IV with 27 × 10⁶ T cells. On day 5 after transplantation, treatment with vehicle or ruxolitinib twice daily was started and carried out for 16 days until mice were sacrificed for organ analysis. (B) FACS histogram plot shows huCD45⁺ cells in the first mouse that had received transplantation. CD45⁺ cells are nearly all T cells, positive for CD4 or double positive for CD4/CD8. The malignant population is characterized as CD4⁺ CD7 low (28% of CD4⁺ cells). (C) Percentage of weight loss of AITL xenografted mice after treatment with vehicle or ruxolitinib compared with starting weight measured on day 0 after transplantation. Statistical significance was calculated for the values on day 19 and day 21 (n = 4 per group). (D) Image of the spleens from AITL engrafted mice treated with vehicle or ruxolitinib for 21 days. (E-I) Comparison of spleen weights and femur cell counts, WBC counts, granulocyte counts, and monocyte counts of vehicle- or ruxolitinib-treated AITL mice. Dashed lines indicate baseline levels (mean of 3 WT NOG mice, ie, without transplantation). (J) Percentage of normal human T cells (hCD45⁺hCD4⁺, hCD45⁺hCD4⁺hCD7⁺, hCD45⁺hCD8⁺, and hCD45⁺hCD4⁺hCD8⁺) and the malignant hCD45⁺hCD4⁺hCD7⁻ cells within total spleen cells after treatment with vehicle vs ruxolitinib and measured by FACS (n = 4 per group). (K) Total amount (× 10⁶) of malignant T cells hCD45⁺hCD4⁺hCD7⁻ in the spleen after the treatment period of 21 days. (L) Kaplan-Meier survival curve for Tx1 xenografted mice treated with vehicle controls (n = 5 for vehicle ruxolitinib and n = 5 for control antibody in 1 curve), ruxolitinib (n = 5), or Ly6G antibody (blue; n = 5). (M-O) Xenografts 2 to 5 (Tx 2-5) from 4 more PTCLs (1 AITL, 2 follicular TCL, and 1 PTCL-NOS). (M,N) Granulocyte counts and spleen weights in mice with xenografts (Tx 2-5) with and without ruxolitinib treatment (all P < .05). (O,P) Kaplan-Meier survival curve of xenografted mice (Tx 2-5) with or without ruxolitinib treatment (O) or Ly6G treatment (P). Bars represent mean values with error bars showing the SEM. Statistical significance was calculated using the Student unpaired t test. ∗P < .05, ∗∗P < .01, ∗∗∗P < .001.