骨髓纤维化（MF）是一种罕见的造血干细胞疾病，可以进展为骨髓（BM）功能衰竭或爆发期。异基因造血干细胞移植（HCT）是对晚期MF患者的一种潜在治疗方法，对于符合条件的患者而言，其具备潜在的治愈效果，但MF与AML的骨髓植入存在延迟导致并发症的问题。由于MF植入的决定因素尚不完全清楚，因此我们在本中心开展了对植入动态的研究。我们对长期随访的71例在2000年至2019年间进行的异基因HCT进行评估，其中超过50%的患者在2015年之后接受了该治疗。中位数中性粒细胞植入时间≥0.5x109/l在移植后+20天，并与骨髓纤维化、脾肿大和输入的CD34+细胞数量相关。原发性MF和继发性MF的植入动态相似，并不受JAK2、CALR和MPL的MF驱动基因突变影响。在接受巴乌弗林达比休养酮-环磷胺氨糖苷-骨髓刺激因子（TBF-PTCy/G-CSF）条件下的半相合异基因HCT中，中性粒细胞植入时间较晚，2000-2019年和2015年之后分别有9.9%和15.6%的患者接受了该治疗方案。血小板植入同样延迟，但网织红细胞的再生受影响较小。由于MF是一种罕见的血液恶性肿瘤，本研究对于MF的大量HCT数据对于证实MF中植入的中性粒细胞和血小板较晚与宿主和治疗相关因素有关十分重要。对于罕见的MF疾病，从这个长期随访队列的观察结果显示，针对该疾病的新型准备方案需要在更大的多中心队列中进行详细评估，以评估也在接受异基因移植的这种罕见造血肿瘤患者的长期移植物功能和整体预后指标。版权所有©2023年Jungius、Adam、Grosheintz、Medinger、Buser、Passweg、Halter和Meyer。

Myelofibrosis (MF) is a rare hematopoietic stem cell disorder progressing to bone marrow (BM) failure or blast phase. Allogeneic hematopoietic cell transplantation (HCT) represents a potentially curative therapy for a limited subset of patients with advanced MF, who are eligible, but engraftment in MF vs. AML is delayed which promotes complications. As determinants of engraftment in MF are incompletely characterized, we studied engraftment dynamics at our center.A longitudinal cohort of 71 allogeneic HCT performed 2000-2019 with >50% after 2015 was evaluated.Median time to neutrophil engraftment ≥0.5x109/l was +20 days post-transplant and associated with BM fibrosis, splenomegaly and infused CD34+ cell number. Engraftment dynamics were similar in primary vs. secondary MF and were independent of MF driver mutations in JAK2, CALR and MPL. Neutrophil engraftment occurred later upon haploidentical HCT with thiotepa-busulfan-fludarabine conditioning, post-transplant cyclophosphamide and G-CSF (TBF-PTCy/G-CSF) administered to 9.9% and 15.6% of patients in 2000-2019 and after 2015, respectively. Engraftment of platelets was similarly delayed, while reconstitution of reticulocytes was not affected.Since MF is a rare hematologic malignancy, this data from a large number of HCT for MF is essential to substantiate that later neutrophil and platelet engraftment in MF relates both to host and treatment-related factors. Observations from this longitudinal cohort support that novel conditioning schemes administered also to rare entities such as MF, require detailed evaluation in larger, multi-center cohorts to assess also indicators of long-term graft function and overall outcome in patients with this infrequent hematopoietic neoplasm undergoing allogeneic transplantation.Copyright © 2023 Jungius, Adam, Grosheintz, Medinger, Buser, Passweg, Halter and Meyer.