Achievement of complete donor chimerism after an allogeneic hematopoietic stem cell transplant is necessary for elimination of underlying malignant disease. A decline in donor chimerism may herald an impending relapse and therefore, early recognition and intervention plays an important role in such cases. A 32 year old male patient diagnosed as a case of Philadelphia positive mixed phenotypic acute leukaemia underwent peripheral blood hematopoietic stem cell transplant (HSCT) with his sibling as donor. During follow-up, a fall in donor chimerism was observed from 91.86% on day +37 to 88.83% on day +57 and 85.34% on day +77. Donor Lymphocyte Infusion (DLI) was harvested via apheresis. A dose of 1 × 10⁶ per kg was infused and the rest was cryopreserved in aliquots of escalating doses. On day +102, he presented with biopsy proven acute mucocutaneous GVHD grade 2 which was managed conservatively and donor chimerism of 57.99%. On day +126, a repeat donor chimerism was performed which showed 100% chimerism. He continues to do well at day +161. Timely use of DLI can improve donor chimerism in patients with Philadelphia positive acute leukaemia who tend to relapse after HSCT.

异基因造血干细胞移植后要实现完全的供体嵌合，对于消除潜在的恶性疾病是必要的。供体嵌合症的减少可能预示着即将发生的复发，因此，在这种情况下，早期识别和干预起着重要的作用。一名32岁男性患者被诊断为费城阳性混合表型急性白血病，其兄弟姐妹为供体，接受了外周血造血干细胞移植（HSCT）。在随访期间，观察到的供体嵌合率从第37天的91.86％下降到第57天的88.83％和第77天的85.34％。通过单采术收集供体淋巴细胞输注（DLI）。剂量为1×10 ⁶每公斤注射一次，其余冷冻保存，并按等量逐步增加剂量。在第102天，他接受了活检证实为急性粘膜皮肤GVHD 2级，保守治疗且供体嵌合率为57.99％。在第+126天，进行重复的供体嵌合，显示出100％的嵌合。在第161天，他继续表现出色。及时使用DLI可以改善HSCT后趋于复发的费城阳性急性白血病患者的供体嵌合。