Allogeneic Hematopoietic Progenitor Cell from Peripheral Whole Blood in Acute Myeloid Leukemia

Acute Myeloid Leukemia (AML) standard treatment involves initial induction therapy administrating two cycles of the 3+7 protocol (3 days anthracycline + 7 days cytarabine), and post-remission therapy of 3 cycles of high-dose cytarabine. The 5-year overall survival is 20 % (PMID: 33734442). During prolonged aplasia, infections and hemorrhages can cause treatment failure and death (PMID: 32236160). That is why transfusions of allogeneic hematopoietic progenitor cells (Allo-HPC) from whole peripheral blood to reduce the time of aplasia and complications were of interest.

We studied 6 patients (3 males, 3 females) with AML (M1, M2), average age 35 years (18-60 years), who received Allo-HPC from whole peripheral blood during aplasia after each 3+7 regimen. The transfusion was performed at day 14 (day 12-16) post-regimen, when patients had neutrophils <100/ul (0-100/ul). Regarding donors, one corresponded to HLA identical sibling, and 5 to haploidentical (2 fathers, 2 mothers and 1 brother), they received G-CSF 300 μg subcutaneously every 12 hours over 3 days, then 450 ml phlebotomy was performed. Phlebotomy displayed median WBC 27,310/ul, neutrophils 21,830/ul, CD34+ cells 9/ul, hemoglobin 14.8 g/dl, and platelets 218,000/ul. Thus, whole peripheral blood obtained was transfused through patients' CVC after premedication with dexamethasone 8 mg and metamizole 1 g. FISH (Y chromosome, Vysis CEP-Y DYZ1) and RT-PCR (HUMARA gene) studies were performed for chimerism analysis.

Recovery of neutrophils >500/ul was observed at day 9 and platelets >20,000/ul at day 6. One case of cutaneous rush was observed as an adverse event. MRD after each cycle reflected 0.01% average. Three patients remain alive with follow-up of 4 years, 5 years and 1 year respectively. Two patients relapsed and died during 1year follow-up. One patient developed optic neuritis and did not receive high-dose cytarabine therapy, relapsed and died after 6 months. None of the patients presented acute or chronic GVHD. Regarding the results of chimerism, one male patient (1year follow-up) showed mixed chimera by FISH (Y=95%) and by RT-PCR (HUMARA gene), such studies were still in progress in the other two women patients.

Contrasting patients who received Allo-HPC from the ones who do not, statistically differences were found in neutrophils recovery and hospital staying, the former displayed 9 + 3 days vs 14 + 4 days (p=0.008) and 19 +5 days vs 25 + 4 days (p=0.009) respectively, infections also decreased from 83% to 25%.

Transfusion of Allogeneic Hematopoietic Progenitor Cell from Peripheral whole blood reduces the duration of aplasia, infections, inpatient stays, and increases survival.

No relevant conflicts of interest to declare.