Strategies to accelerate immune recovery after allogeneic hematopoietic stem cell transplantation

The interplay existing between immune reconstitution and patient outcome has been extensively demonstrated in allogeneic hematopoietic stem cell transplantation. One of the leading causes of infection-related mortality is the slow recovery of T-cell immunity due to the conditioning regimen and/or age-related thymus damage, poor naïve T-cell output, and restricted T-cell receptor (TCR) repertoires. With the aim of improving posttransplantation immune reconstitution, several immunotherapy approaches have been explored. Donor leukocyte infusions are widely used to accelerate immune recovery, but they carry the risk of provoking graft-versus-host disease. This review will focus on sophisticated strategies of thymus function-recovery, adoptive infusion of donor-derived, allodepleted T cells, T-cell lines/clones specific for life-threatening pathogens, regulatory T cells, and of T cells transduced with suicide genes.     

异基因造血干细胞移植后的相关并发症及危险因素

背景：有效预防和治疗异基因造血干细胞移植后并发症是提高患者存活率的重要因素。 目的：分析异基因造血干细胞移植后相关并发症的发生和危险因素。 方法：应用文献检索的方法获取异基因造血干细胞移植后相关并发症研究的文献,对符合研究标准的文献进行深入的数据分析,文章选取异基因造血干细胞移植后极易发生的并发症进行分析,如肺部并发症、真菌性败血症、巨细胞病毒感染以及中枢神经系统并发症等。 结果与结论：异基因造血干细胞移植后易出现肺部并发症,而且死亡率较高,肺部并发症的发病机制可能与移植物抗宿主病和巨细胞病毒抗原血症相关。异基因造血干细胞移植后真菌性败血症病原菌以假丝酵母菌属为主,死亡率较高,应二级预防性和早期经验性抗真菌治疗。更昔洛韦、膦甲酸钠对异基因造血干细胞移植后巨细胞病毒感染的治疗有效。中枢神经系统并发症在异基因造血干细胞移植后发生率较低,但在治疗过程也不容忽视。异基因造血干细胞移植后相关并发症的发生与多种危险因素有关,在临床治疗过程中要对相关因素采取预防措施,减少并发症的发生,提高患者的存活率。     

Lung transplantation for bronchiolitis obliterans after allogeneic hematopoietic stem cell transplantation

Bronchiolitis obliterans (BO) is a late onset complication of allogeneic hematopoietic stem cell transplantation (HSCT), and treatment outcome is dismal if it does not respond to immunosuppressive therapy. A 21-year-old male diagnosed with acute myeloid leukemia received an allogeneic HSCT from human leukocyte antigen- identical sibling donor. Twenty one months after transplantation, he developed progressive dyspnea and was diagnosed BO. Despite standard immunosuppressive therapy, the patient rapidly progressed to respiratory failure and Novalung® interventional lung-assist membrane ventilator was applied in the intensive care unit. Three months after the diagnosis of BO, the patient underwent bilateral lung transplantation (LT) and was eventually able to wean from the ventilator and the Novalung®. Since the LT, the patient has been under a strict rehabilitation program in order to overcome a severe lower extremity weakness and muscle atrophy. Histologic findings of the explanted lungs confirmed the diagnosis of BO. Nine months after the LT, the patient showed no signs of rejection or infectious complications, but still required rehabilitation treatment. This is the first LT performed in a patient with BO after allogeneic HSCT in Korea. LT can be an effective therapy in terms of survival for patients with respiratory failure secondary to development of BO following HSCT.     

Erythrocyte transfusion practices after allogeneic hematopoietic stem cell transplantation]

Allogeneic peripheral blood hematopoietic stem cell transplantation is being evaluated in a randomized French study comparing the use of peripheral blood stem cells vs. bone marrow graft stem cells. In order to standardize immunohematological (IH) assessment and transfusion practices within our protocol, we made suggestions to 25 allo-transplantation French centers on the following elements: pre-inclusion IH assessment, IH exclusion criteria, transfusion rules, post-transplantation IH surveillance and treatment of hemolysis. The analysis of their responses to our suggestions led us to elaborate recommendations which were approved and implemented by the French Bone Marrow Transplantation Society (SFGM). These recommendations concern the transfusion practice in the general framework of allogeneic hematopoietic stem cell transplantation and can therefore be considered as referential.     

Time to explore preventive and novel therapies for bronchiolitis obliterans syndrome after allogeneic hematopoietic stem cell transplantation

Although allogeneic hematopoietic stem cell transplant (allo-HSCT) is performed to treat otherwise incurable and fatal diseases, transplantation itself can lead to life-threatening complications due to organ damage. Pulmonary complications remain a significant barrier to the success of allo-HSCT. Lung injury, a frequent complication after allo-HSCT, and noninfectious pulmonary deaths account for a significant proportion of non-relapse mortality. Bronchiolitis obliterans syndrome (BOS) is a common and potentially devastating complication. BOS is now considered a diagnostic criterion of chronic graft-versus-host-disease (cGVHD), and National Institutes of Health (NIH) consensus has been published to establish guidelines for diagnosis and monitoring of BOS. It usually occurs within the first 2 years but may develop as late as 5 years after transplantation. Recent prevalence estimates suggest that BOS is likely underdiagnosed, and when severe BOS does occur, current treatments have been largely ineffective. Prevention and effective novel approaches remain the primary tools in the clinician's arsenal in managing BOS. This article provides an overview of the currently available and novel strategies for BOS, and we also discuss specific preventive interventions to reduce severe BOS after allo-HSCT. Therapeutic trials continue to be needed for this orphan disease.     

Varicella zoster virus meningoencephalitis after allogeneic hematopoietic stem cell transplantation

Although the reactivation of varicella zoster virus (VZV) is a common complication after allogeneic hematopoietic stem cell transplantation (HSCT), VZV meningoencephalitis is a rare life-threatening infectious disease after HSCT. We describe here a patient who developed VZV meningoencephalitis 2 years after human leukocyte antigen-matched unrelated HSCT for acute myeloblastic leukemia. She developed chronic graft-versus-host disease, and cyclosporine (CSA) was continued until 17 months after HSCT. Low-dose acyclovir (ACV) at 200 mg/day was administered to prevent the reactivation of VZV from day -7 to the termination of CSA. At 22 months, she suddenly developed fever, loss of consciousness, and seizure, with generalized skin rash. A high level of VZV DNA was detected in her cerebrospinal fluid (CSF). She was diagnosed to have VZV meningoencephalitis. Intravenous ACV at 30 mg/kg/day was given for 2 months. Although loss of consciousness was quickly resolved, some neurologic symptoms persisted. She did not have any known risk factors for VZV reactivation. Therefore, we should keep in mind that any HSCT recipient may develop VZV meningoencephalitis, and examination of CSF for VZV infection with an empiric administration of ACV may be recommended for HSCT recipients with central nervous system symptoms, even in the absence of skin manifestations.     

Sirolimus and thrombotic microangiopathy after allogeneic hematopoietic stem cell transplantation.

Thrombotic microangiopathy (TMA) may occur after allogeneic hematopoietic stem cell transplantation (HSCT) and is related in part to calcineurin inhibitor toxicity. We observed a higher-than-expected rate of TMA when calcineurin inhibitors were combined with sirolimus. To determine the incidence of and risk factors for TMA after HSCT, we performed a retrospective cohort analysis of myeloablative allogeneic HSCT recipients between 1997 and 2003. TMA diagnosis required the simultaneous occurrence of (1) creatinine increase >2 mg/dL or >50% above baseline, (2) schistocytosis, (3) increased lactate dehydrogenase, and (4) no evidence of disseminated intravascular coagulopathy. A total of 111 sirolimus-exposed subjects were compared with 216 nonexposed subjects after HSCT. TMA occurred in 10.8% of the sirolimus group and 4.2% in the nonsirolimus group (odds ratio, 2.79; P=.03). Sirolimus exposure was associated with TMA earlier than in nonsirolimus patients (25 versus 58 days; P=.04). Only the use of sirolimus (exact odds ratio, 3.49; P=.02) and grade II to IV acute graft-versus-host disease (exact odds ratio, 6.60; P=.0002) were associated with TMA in regression analyses. Treatment of TMA varied among affected individuals. Renal recovery was complete in 92% of sirolimus-treated patients. Overall survival after TMA diagnosis was better for sirolimus subjects than for nonsirolimus subjects (58.3% versus 11.1%; P=.02). Sirolimus seems to potentiate the effects of calcineurin inhibitors on TMA after HSCT. TMA associated with sirolimus seems reversible and has a favorable prognosis when compared with TMA associated with calcineurin inhibitors alone. A careful monitoring strategy for TMA should be used with a sirolimus-containing graft-versus-host disease prophylaxis regimen.     

Voriconazole and sirolimus coadministration after allogeneic hematopoietic stem cell transplantation.

Sirolimus is increasingly used in transplantation for prevention and treatment of graft-versus-host disease and organ rejection. Voriconazole is contraindicated when used concomitantly with sirolimus because of a substantial increase in sirolimus drug exposure with unadjusted dosing, but voriconazole is also considered the best initial treatment of invasive aspergillosis and other fungal infections. Patients who received voriconazole and sirolimus concomitantly were identified by a review of the medical records of all allogeneic hematopoietic stem cell recipients at our institution from September 1, 2002, to June 1, 2005. Data including baseline characteristics, indications for both drugs, and potential adverse effects were evaluated. Eleven patients received voriconazole and sirolimus concomitantly for a median of 33 days (range, 3-100 days). In 8 patients whose sirolimus dose was initially reduced by 90%, trough sirolimus levels were similar to those obtained before the administration of voriconazole; no obvious significant toxicity from either drug was observed during coadministration. Serious adverse events were observed in 2 patients in whom sirolimus dosing was not adjusted during voriconazole administration. Sirolimus and voriconazole may be safely coadministered if there is an empiric initial 90% sirolimus dose reduction combined with systematic monitoring of trough levels.     

Chronic kidney disease after myeloablative allogeneic hematopoietic stem cell transplantation.

Because survival of recipients of allogeneic hematopoietic stem cell transplantation (HSCT) has improved, long-term complications become more important. We studied the incidence and risk factors of chronic kidney disease in these patients and evaluated associated posttransplant complications and mortality. We performed a retrospective cohort study of 266 adults who received myeloablative allogeneic HSCT and who survived for >6 months in an 11-year period at a Dutch university medical center. Primary outcome was the incidence of chronic kidney disease defined as a glomerular filtration rate (GFR) of <60 mL/min/1.73 m(2). Chronic kidney disease developed in 61 (23%) of 266 patients, with a cumulative incidence rate of 27% at 10 years. Severe kidney disease (GFR of <30 mL/min/1.73 m(2)) developed in 3% of patients. Only 6 patients developed the thrombotic microangiopathic syndrome SCT nephropathy, and 2 of them needed dialysis. Pretransplant risk factors for chronic kidney disease were lower GFR at day 0 (P < .0001, odds ratio [OR] 0.95 95% confidence interval [CI] 0.93-0.97), female gender, and higher age (P = .001 and P < .0001, respectively). The occurrence of hypertension after transplantation was associated with chronic kidney disease (P < .0001, OR 0.34 95% CI 0.18-0.62). Mortality was 39% after a mean follow-up of 5.1 years. There was no significant difference in survival between patients with and without chronic kidney disease. Chronic kidney disease is a common late complication of myeloablative allogeneic HSCT. Because of the natural decline in renal function with time there is a risk of developing end-stage renal disease in the future. SCT nephropathy seems to be a specific cause of chronic kidney disease that is typically associated with severe kidney disease.     

Preemptive cellular immunotherapy after T-cell-depleted allogeneic hematopoietic stem cell transplantation.

GVHD is a life-threatening complication of allogeneic hematopoietic stem cell transplantation (HSCT). GVHD is due to donor lymphocytes that are cotransplanted with donor stem cells. These donor lymphocytes are primed by histocompatibility differences between donors and recipients and activated by a cytokine storm caused by the conditioning regimen. The most efficient method for prevention of GVHD consists of T-cell depletion (TCD) of the graft. However, TCD usually leads to an increased risk of leukemia relapse because of the loss of the graft-versus-leukemia (GVL) effect. Several groups have studied the feasibility of preemptive donor lymphocyte infusion (DLI) to lessen the impact of TCD on leukemia relapse. Preemptive DLI is given several weeks to months after the transplantation, ie, after the cytokine storm and after the patient has recovered from conditioning-regimen-related toxicities. After briefly discussing various techniques of TCD of the graft and the efficacy of DLI, this article reviews the first clinical studies evaluating a strategy of TCD of the graft followed by preemptive DLI.     

Cytomegalovirus management after allogeneic hematopoietic stem cell transplantation: A mini-review

Because of the high incidence of cytomegalovirus (CMV) seropositivity in the population, CMV infection is a common and severe complication of allogeneic hematopoietic stem cell transplantation (allo-HSCT) in Taiwan. Here we propose a CMV management strategy for patients undergoing allo-HSCT from the Taiwanese perspective, which focuses on the epidemiology, diagnosis, monitoring, prophylaxis, and treatment of CMV infection after allo-HSCT. In terms of CMV monitoring, weekly CMV monitoring with the COBAS® AmpliPrep system is the standard approach because the pp65 CMV antigenemia assay has a lower sensitivity than CMV monitoring with the COBAS® AmpliPrep system. However, pp65 CMV antigenemia assay has a better correlation with clinical symptoms in immunocompromised patients. A 14-week prophylactic course of letermovir is recommended for allo-HSCT recipients in Taiwan, especially for recipients of hematopoietic stem cells from mismatched unrelated and haploidentical donors. Preemptive ganciclovir therapy should be initiated when the CMV viral load exceeds 1000 copies/mL, and should not be discontinued until CMV DNA is no longer detected in the blood. For allo-HSCT recipients who have CMV-related diseases, ganciclovir with or without CMV-specific intravenous immunoglobulin is the standard of care. The limited availability of foscarnet, an alternative for patients who are not responsive to or cannot tolerate ganciclovir, is a crucial issue in Taiwan. For pediatric allo-HSCT recipients, more data are needed to propose a CMV management recommendation.     

Clinical tolerance in allogeneic hematopoietic stem cell transplantation

Allogeneic hematopoietic stem cell transplantation (HSCT) has been a curative therapeutic option for a wide range of immune hematologic malignant and non-malignant disorders including genetic diseases and inborn errors. Once in the host, allogeneic transplanted cells have not only to ensure myeloid repopulation and immunological reconstitution but also to acquire tolerance to host human leukocyte antigens via central or peripheral mechanisms. Peripheral tolerance after allogeneic HSCT depends on several regulatory mechanisms aimed at blocking alloimmune reactivity while preserving immune responses to pathogens and tumor antigens. Patients transplanted with HSCT represent an ideal model system in humans to identify and characterize the key cellular and molecular players underlying these mechanisms. The knowledge gained from these studies has allowed the development of novel therapeutic strategies aimed at inducing long-term peripheral tolerance, which can be applicable not only in allogeneic HSCT but also in autoimmune diseases and solid-organ transplantation. In the present review, we describe Type 1 regulatory T cells, initially discovered and characterized in chimeric patients transplanted with human leukocyte antigen-mismatched HSCT, and how their presence correlates to tolerance induction and maintenance. Furthermore, we summarize different cell therapy approaches with regulatory T cells, designed to facilitate tolerance induction, minimizing pharmaceutical interventions.     

白消安在非亲缘异基因造血干细胞移植预处理中的应用

背景：口服白消安剂型胃肠道吸收不稳定,影响异基因造血干细胞疗效且毒性增加。静脉剂型白消安在国内最近几年用于临床,但在非亲缘异基因移植预处理中应用的相关报道甚少。 目的：探讨静脉剂型白消安在非亲缘异基因造血干细胞移植预处理中应用的疗效并观察其毒副作用。 方法：14例非亲缘异基因干细胞移植采用静脉剂型白消安联合环磷酰胺预处理方案,18例亲缘异基因干细胞移植采用口服白消安联合环磷酰胺预处理方案,观察两组造血重建、植入率等疗效指标及胃肠道反应、口腔黏膜炎、出血性膀胱炎、肝功能损害、移植物抗宿主病等相关毒性指标。 结果与结论：两组患者植入率均为100%。静脉剂型组肝脏毒性、口腔黏膜炎发生率明显低于口服剂型组(14% vs. 67%,7% vs. 55%),差异均有显著性意义(P < 0.01),而胃肠道反应、出血性膀胱炎、造血重建、急性移植物抗宿主病、局限性移植物抗宿主病等方面差异均无显著性意义(P > 0.05)。结果可见静脉剂型白消安应用于非亲缘异基因造血干细胞移植预处理可获得满意疗效,且毒副反应少。     

单倍型异基因造血干细胞移植后发生巨细胞病毒感染的临床分析

目的 探讨单倍型异基因造血干细胞移植后发生巨细胞病毒(CMV)感染的临床特点及治疗.方法 对北京军区总医院血液科2011年1月-2013年1月采用单倍型异基因造血干细胞移植治疗的50例患者的临床资料进行回顾性研究,供者接受粒细胞集落刺激因子动员,采用骨髓加外周血干细胞联合移植,预处理方案以改良BUCY方案为主,移植后监测CMV-DNA,分析CMV感染的特点并探讨其治疗方法.结果 全部患者中男32例,女18例,年龄5-45岁,平均年龄23.8岁,其中共12例发生CMV血症,发生率为24％,首次检出CMV-DNA中位时间是移植后50天(36-72),CMV定量范围为2.4×103-6.2×106拷贝/mL,其中6例为CMV相关性出血性膀胱炎,2例为CMV相关性间质性肺炎,抗CMV治疗后全部患者CMV-DNA转阴.结论 单倍型异基因造血干细胞移植后巨细胞病毒感染发生率高,更昔洛韦、膦甲酸钠抗病毒治疗疗效可靠、不良反应少.     

High-dose, post-transplantation cyclophosphamide to promote graft-host tolerance after allogeneic hematopoietic stem cell transplantation

Graft-versus-host disease, or GVHD, is a major complication of allogeneic hematopoietic stem cell transplantation (alloHSCT) for the treatment of hematologic malignancies. Here, we describe a novel method for preventing GVHD after alloHSCT using high-dose, post-transplantation cyclophosphamide (Cy). Post-transplantation Cy promotes tolerance in alloreactive host and donor T cells, leading to suppression of both graft rejection and GVHD after alloHSCT. High-dose, post-transplantation Cy facilitates partially HLA-mismatched HSCT without severe GVHD and is effective as sole prophylaxis of GVHD after HLA-matched alloHSCT. By reducing the morbidity and mortality of alloHSCT, post-transplantation Cy may expand the applications of this therapy to the treatment of autoimmune diseases and non-malignant hematologic disorders such as sickle cell disease.     

Bone density loss after allogeneic hematopoietic stem cell transplantation: a prospective study.

The incidence and course of bone density abnormalities following hematopoietic stem cell transplantation are poorly understood and complicated by the impact of multiple factors. Hip, spine, and wrist bone mineral densities (BMDs) were measured in 104 adults (54 women, 54 men; mean age, 40 years [range, 18-64 years]) at 3 and 12 months after allogeneic transplantation. Clinical and laboratory variables were evaluated using univariate and multivariate analyses to determine risk factors for osteoporosis, fracture, and avascular necrosis. At 3 months posttransplantation, combined (male and female) hip, spine, and wrist z scores were -0.35, -0.42, and +0.04 standard deviations, respectively. At 12 months both men and women experienced significant loss of hip BMD (4.2%, P < .0001); changes in the spine and wrist were minimal. The cumulative dose and number of days of glucocorticoid therapy and the number of days of cyclosporine or tacrolimus therapy showed significant associations with loss of BMD; age, total body irradiation, diagnosis, and donor type did not. Nontraumatic fractures occurred in 10.6% of patients and avascular necrosis in 9.6% within 3 years posttransplantation. The decrease in height between pretransplantation and 12 months posttransplantation was significant (P = .0001). Results indicate that loss of BMD after allogeneic stem cell transplantation is common and accelerated by the length of immunosuppressive therapy and cumulative dose of glucocorticoid. An increased incidence of fracture and avascular necrosis may adversely impact long-term quality of life. Prevention of bone demineralization appears warranted after stem cell transplantation.     

Reimmunization after hematopoietic stem cell transplantation

Hematopoietic stem cell transplant recipients lose immune memory of exposure to infectious agents and vaccines accumulated through a lifetime, and therefore need to be revaccinated. Reimmunization protocols vary greatly among hematopoietic stem cell transplant centers. Diphtheria and tetanus toxoids, pertussis vaccine, Haemophilus influenza type B conjugate, 23-valent pneumococcal polysaccharide, inactivated influenza and polio vaccine and live attenuated measles-mumps-rubella vaccine are the currently recommended vaccines to be included in a vaccination program after hematopoietic stem cell transplant. Other variables, such as stem cell source, new adjuvants, T-cell depleted transplants, nonmyeloablative conditioning and donor immunization have recently been introduced and a constant update of current recommendations are needed. Studies recently published, the use of other vaccines and the perspectives for different vaccination protocols are discussed in this review.     

TLR4 inactivation protects from graft-versus-host disease after allogeneic hematopoietic stem cell transplantation

Graft-versus-host disease (GVHD) is the most common complication after hematopoietic stem cell transplantation. To clarify the role of Toll-like receptor 4 (TLR4), which is a major receptor for bacterial lipopolysaccharides (LPS), in the development of acute GVHD, we used a TLR4-knockout (TLR4^−/−) mouse GVHD model and analyzed the underlying immunological mechanisms. When TLR4^−/− mice were used as bone marrow and splenocyte cell graft donors or recipients, GVHD symptom occurrence and mortality were delayed compared to wild-type (TLR4^+/+) mice. In addition, histopathological analyses revealed that in TLR4^−/−→BALB/c chimeras, liver and small intestine tissue damage was reduced with minimal lymphocytic infiltration. In contrast to TLR4^+/+, TLR4^−/− mice dendritic cells did not express CD80, CD86, CD40, MHC-II or IL-12 during LPS induction and remained in an immature state. Furthermore, the ability of TLR4^−/− mice spleen dendritic cells to promote allogeneic T-cell proliferation and, in particular, T-helper cell 1 (Th1) development was obviously attenuated compared with TLR4^+/+ mice dendritic cells, and the levels of interferon-γ (IFN-γ) and IL-10, Th2-cell specific cytokines, were significantly higher in the serum of TLR4^−/−→BALB/c than in TLR4^+/+→BALB/c chimeric mice. Overall, our data revealed that TLR4 may play a role in the pathogenesis of GVHD and that targeted TLR4 gene therapy might provide a new treatment approach to reduce the risk of GVHD.     

Second malignancies after allogeneic hematopoietic cell transplantation.

Allogeneic hematopoietic cell transplantation (allo-HCT) may prolong life and cure patients suffering from otherwise fatal diseases. However, the growing population of long-term survivors has led to the realization of multiple long-term complications, including the risk of second malignancies. Compared to the autologous setting, allo-HCT carries a much higher risk of posttransplant lymphoproliferative disorder (PTLD), which usually occurs within the first year after allo-HCT and is strongly associated with the Epstein-Barr virus (EBV). Treatment-related myelodysplastic syndromes (tMDS) and second leukemias are extremely rare. Both autologous and allo-HCT carry increased risks for second solid malignancies (SSM). The cumulative incidence of SSM continues to increase in each of the largest studies with as much as 20 years of follow-up, likely related to the long latency of radiation-related SSM. Systematic, prospective monitoring, vigilant screening processes, and well-maintained survivorship clinics and databases are absolute necessities, and should be included in the infrastructure of individual transplant centers and networks, with mandatory periodic reporting of second malignancy incidences. Primary care and transplant physicians alike must be aware of the risk of second malignancies after allo-HCT. Most importantly, guidelines should be developed in regard to screening and prevention of second malignancies, so that physicians can provide state-of-the-art counsel and care for the benefit of our patients.     

异基因造血干细胞移植后肺部并发症的发生和危险因素分析

目的探讨治疗恶性血液病异基因造血干细胞移植（allo—HSCT）后肺部并发症与相关危险因素的关系。方法回顾性分析1991年8月至2004年6月157例allo—HSCT患者的临床资料。结果71例患者发生87例次肺部并发症，其中15例患者发生2次以上肺部并发症，总发生率为45.2％。直接死于肺部并发症者37例（23．6％），发生中位时间103d（1～886d）。其中细菌性肺炎32例，间质性肺炎8例，肺真菌病3例，肺水肿3例，肺结核2例，肺栓塞1例，2种或2种以上病原所致的肺部并发症38例次。单因素分析显示：患者年龄、疾病状态、供受者关系、HLA配型相合程度及广泛型慢性移植物抗宿主病（cGVHD）是影响移植后肺部并发症的危险因素。多因素分析显示：疾病状态和广泛型cGVHD与肺部并发症的发生显著相关（P＜0．01）。结论肺部并发症是allo—HSCT后常见的并发症之一。患者移植时疾病状态和广泛型cGVHD是与allo—HSCT后肺部并发症发生相关的危险因素。