Case vignette. A 32-year-old man with a history of MUD-alloHSCT for relapsed mediastinal large cell lymphoma underwent second MUD-alloHSCT for therapy-related MDS (t-MDS) with complex karyotype and del7q. He relapsed at day (d) +270 with chimerism studies revealing 99% donor T cells and 90% donor myeloid cells. Chimerism studies on day +322 indicated further decrease of donor myeloid chimerism to 80%. Immunosuppression with sirolimus was tapered and ended by day +311. Administration of azacitidine in combination with dose-adjusted venetoclax due to anti-fungal prophylaxis led to MRD^neg complete remission (CR) by day +353 with concomitant increase in donor myeloid chimerism to 92%. Three courses of DLI were administered from d+381 through d+561 at escalating dose levels of 1 × 10⁶ to 5 × 10⁶/kg. Donor myeloid chimerism was fully restored 30 days after the second course of DLI. The patient continues to be in MRD^neg CR with complete donor chimerism at 2 years after relapse. ¹Dose adjusted to 100 mg daily because of concomitant antifungal prophylaxis.