目的 探讨异基因造血干细胞移植（allo-HSCT）治疗儿童高危急性T淋巴细胞白血病（T-ALL）的疗效及预后影响因素，比较不同治疗方案的疗效差异，探讨预处理方案对T-ALL患者allo-HSCT的影响。比较含克拉屈滨（Cla）与不含Cla（氟达拉滨，Flu）两种预处理方案在脐血移植（UCBT）中的效果，以及与基于全身照射（TBI）的外周血造血干细胞移植（PBSCT）方案的差异。 方法 回顾性分析2017年2月至2023年3月接受allo-HSCT的高危T-ALL患儿的临床资料。采用Kaplan-Meier法分析患儿3年的总生存（OS）率、无白血病生存（LFS）率、慢性移植物抗宿主病（cGVHD）累积发生率、累积复发率（CIR）、累积移植相关死亡率（TRM），采用Log-rank检验分析影响高危T-ALL患儿预后的因素。比较含克拉屈滨（Cla）预处理方案的UCBT组、含氟达拉滨（Flu）预处理方案的UCBT组和基于全身照射（TBI）预处理的外周血造血干细胞移植（PBSCT-TBI）组3组之间预处理相关毒性反应、移植后感染以及3年OS率差异。 结果 在23例高危T-ALL患儿中，男19例（82.6%）、女4例（17.4%），中位年龄为9.5（1.9~14）岁，诊断至移植的中位时间为7.5（6~29）个月。23例高危T-ALL患儿中性粒细胞均成功植入，UCBT患儿植入中位时间为18（12~38）d，PBSCT患儿植入中位时间12（11~15）d。UCBT患儿血小板植入中位时间为36（27~61）d，其中1例血小板未植入；PBSCT患儿血小板均植入，植入中位时间为13（9~25）d。5例（21.7%）患儿出现3级以上预处理相关毒性反应（主要表现为胃肠道反应、口腔黏膜炎、感染），14例为1~2级毒性反应，4例未发生毒性反应。23例患儿移植100天内无死亡发生，Ⅲ~Ⅳ度aGVHD发生率为26.1%（6/23），3年的cGVHD累积发生率为（27.15±13.33）%。共18例（78.3%）在移植后发生不同部位及不同程度的感染，以肺炎（10例）、BK多瘤病毒感染相关出血性膀胱炎（7例）以及侵袭性真菌感染（6例）为主。23例患儿移植后中位随访时间34（5~92）个月，LFS 18例、死亡5例。23例患儿3年OS为（77.5±8.9）%，LFS与OS一致。3年CIR及TRM分别为（13.04±7.19）%和（9.21±6.4）%。PBSCT-TBI组中性粒细胞及血小板植入时间均短于UCBT-Cla组和UCBT-Flu组（P<0.05）。UCBT-Cla组、UCBT-Flu组、PBSCT-TBI组之间预处理毒性反应，aGVHD及cGVHD发生率、移植后感染、3年OS率差异均无统计学意义（P>0.05）。Log-rank检验发现，初诊时中枢神经系统（CNS）受累可能为影响高危T-ALL患儿OS的高危因素（P<0.05）；年龄≥10岁、初诊时有CNS受累、移植前疾病状态为二次完全缓解（CR2）和符合难治性白血病可能为高危T-ALL移植后复发的高危因素（P<0.05）。 结论 allo-HSCT可有效改善儿童高危T-ALL的长期生存，且TRM较低。初诊CNS受累是预后不良的重要标志。含Cla的预处理方案在UCBT中展现出降低复发率、提高生存率的潜力。UCBT-Cla方案可能是一种有前景的替代选择，值得进一步研究。

Objective To explore the efficacy and prognostic factors of allogeneic hematopoietic stem cell transplantation (allo-HSCT) in the treatment of high-risk acute T-lymphoblastic leukemia (T-ALL) in children, compare the efficacy differences of different treatment regimens, and explore the influence of pretreatment regimens on allo-HSCT in T-ALL patients. To compare the effects of two conditioning regimens, one containing cladribine (Cla) and the other without (fludarabine, Flu), in umbilical cord blood transplantation (UCBT), as well as the differences between this and the peripheral blood hematopoietic stem cell transplantation (PBSCT) based on total body irradiation (TBI). Methods A retrospective analysis was conducted on the clinical data of children with high-risk T-ALL who underwent allo-HSCT from February 2017 to March 2023. The Kaplan-Meier method was used to analyze the 3-year overall survival (OS) rate, leukemia-free survival (LFS) rate, cumulative incidence of chronic graft-versus-host disease (cGVHD), cumulative incidence of relapse (CIR), and cumulative transplant-related mortality (TRM) of the children. The Log-rank test was used to analyze the factors influencing the prognosis of high-risk T-ALL children. The differences in pre-treatment related toxic reactions, post-transplant infections, and 3-year OS rates among different pre-treatment regimens (UCBT-Cla group, UCBT-Flu group, and PBSCT-TBI group) were compared. Results Among the 23 children with high-risk T-ALL, 19 were boys (82.6%) and 4 were girls (17.4%), with a median age of 9.5 (1.9-14) years, and the median time from diagnosis to transplantation was 7.5 (6-29) months. Among the 23 high-risk T-ALL children, neutrophil engraftment was successfully achieved in all cases. The median time to engraftment was 18 (12 - 38) days for UCBT patients and 12 (11 - 15) days for PBSCT patients. The median time to platelet engraftment was 36 (27-61) days in UCBT recipients, with one case failing to achieve platelet engraftment; all PBSCT recipients achieved platelet engraftment, with a median time of 13 (9-25) days. Five children (21.7%) experienced grade ≥3 conditioning-related toxicities (primarily manifested as gastrointestinal reactions, oral mucositis, and infections), 14 had grade 1-2 toxicities, and 4 had no toxicities. No deaths occurred within 100 days post-transplantation among the 23 children. The incidence of grade Ⅲ-Ⅳ aGVHD was 26.1% (6/23). The 3-year cumulative incidence of cGVHD was (27.15 ± 13.33) %. Eighteen children (78.3%) experienced infections of varying severity and locations after transplantation, primarily pneumonia (10 cases), BK polyomavirus-associated hemorrhagic cystitis (7 cases), and invasive fungal infections (6 cases). The median post-transplant follow-up time was 34 (5-92) months. LFS was observed in 18 children, and 5 children died. The 3-year OS and LFS rate were both (77.5 ± 8.9) %. The 3-year CIR and TRM were (13.04 ± 7.19) % and (9.21 ± 6.4)%, respectively. The neutrophil and platelet engraftment times in the PBSCT-TBI group were significantly shorter than those in the UCBT-Cla and UCBT-Flu groups (P<0.05). No statistically significant differences were observed among the UCBT-Cla, UCBT-Flu, and PBSCT-TBI groups in terms of conditioning-related toxicities, incidence of aGVHD and cGVHD, post-transplant infections, or 3-year OS rate (P>0.05). The log-rank test revealed that central nervous system (CNS) involvement at initial diagnosis may be a high-risk factor affecting the overall survival (OS) of children with high-risk T-ALL (P<0.05). Age≥10 years, CNS involvement at initial diagnosis, pre-transplant disease status in second complete remission (CR2), and meeting the criteria for refractory leukemia may be high-risk factors for post-transplant relapse in high-risk T-ALL (P<0.05). Conclusions Allo-HSCT can effectively improve long-term survival in children with high-risk T-ALL and is associated with low TRM. CNS involvement at initial diagnosis is an important marker of poor prognosis. The cla-containing conditioning regimen in UCBT demonstrates potential for reducing relapse rates and improving survival outcomes. The Cla-containing conditioning regimen demonstrates potential in UCBT to reduce relapse rates and improve survival. The UCBT-Cla regimen may be a promising alternative option worthy of further investigation.