Conditioning of recipients with CD45-ADC along with anti-CD40L mAb and JAK inhibitor can improve overall allogeneic engraftment. B6 (H-2^b) recipients (10- to 12-week-old female) were conditioned with 3 mg/kg isotype-ADC or CD45-ADC on d-2 and 50 cGy (x = cGy in figure) TBI on d-1. All groups of mice were transplanted with 40 × 10⁶ BALB/c (H-2^d) BM on d0. Recipients were treated with anti-CD40L mAb (200 μg) from d-1 to d+14 post-BMT. Ruxolitinib (30 mg/kg) or tofacitinib (30 mg/kg) was administered from d0 through d+14 post-BMT. Baricitinib (200 μg) was administered once daily for 5 days per week for 2 weeks post-BMT. (A) Donor cells (H-2^d) engraftment in the PB of transplanted mice was assessed at 12 weeks post-BMT by flow cytometry. Pooled data from 2 experiments are shown (n = 10 to 14 mice per group). (B) Multilineage peripheral donor chimerism was analyzed at 18 weeks post-BMT by flow cytometry (n = 6 to 7 mice per group). (C-J) Recipients (n = 5 mice per group) were killed at 25 weeks post-BMT, and cells isolated from BM (C,D), thymus (E,F), and spleen (G-J) were analyzed by flow cytometry. (A-J) Data represent mean ± SEM. *P < .05, **P < .01, ***P < .001, ****P < .0001, 2-tailed Student t test.