Analysis of immune-mediated toxicity in CLL murine model. (A) Representative histology findings in liver, small intestine, and colon of Eμ-TCL1 CLL-bearing recipient mice treated as described in Figure 4. Circles and arrows depict sites showing signs of toxicity (original magnification, ×20; hematoxylin & eosin stain). (B) Average toxicity grade per group (n = 5 mice per group, from Figure 4). (C) Linear regression of peripheral Treg count vs incidence of toxicity reveals an inverse correlation. (D) Percentage weight loss in the GVHD murine model normalized to weight prior to sublethal irradiation (inhibitors were administered at 100 mg/kg, once daily, oral gavage; n = 6 mice per group). (E) Submandibular bleeds were collected from each mouse on day 8, and immunophenotyping was performed by flow cytometry to detect peripheral CD4⁺ CD25^HI FoxP3⁺ Tregs. Data are mean + standard deviation. Data are representative of 3 independent in vivo experiments. *P < .05, **P < .005, ***P < .0005, ordinary 1-way ANOVA.