Failure of trilineage blood cell reconstitution after initial neutrophil engraftment in patients undergoing allogeneic hematopoietic cell transplantation – frequency and outcomes

Impact of post-transplant cyclophosphamide and splenomegaly on primary graft failure and multi-lineage cytopenia after allogeneic hematopoietic cell transplantation

Primary graft failure (PGF) and multi-lineage cytopenia (MLC) increase the risk of nonrelapse mortality in allogeneic hematopoietic cell transplants (HCT). We evaluated the impact of post-transplant cyclophosphamide (PTCy) and splenomegaly on PGF and MLC for hematological malignancies. This study included patients with PTCy (N=84) and conventional graft-vs.-host disease prophylaxis (N=199). The occurrence of splenomegaly varied widely, ranging from 17.1 % (acute myeloid leukemia) to 66.7 % (myeloproliferative neoplasms). Ten patients (N=8 in the PTCy and N=2 in the non- PTCy) developed PGF, and 44 patients developed MLC (both N=22). PTCy and severe splenomegaly (≥20 cm) were risk factors for PGF (odds ratio (OR): 10.40, p<0.01 and 6.74, p=0.01 respectively). Moreover, severe splenomegaly was a risk factor for PGF in PTCy patients (OR: 10.20, p=0.01). PTCy (hazard ratio (HR) 2.09, p=0.02), moderate (≥15, <20 cm, HR 4.36, p<0.01), and severe splenomegaly (HR 3.04, p=0.01) were independent risk factors for MLC. However, in subgroup analysis in PTCy patients, only mild splenomegaly (≥12, <15 cm, HR 4.62, p=0.01) was a risk factor for MLC. We recommend all patients be screened for splenomegaly before HCT, and PTCy is cautioned in those with splenomegaly.

Reduced proliferation of bone marrow MSC after allogeneic stem cell transplantation is associated with clinical outcome

Engraftment and differentiation of donor hematopoietic stem cells is decisive for the clinical success of allogeneic stem cell transplantation (alloSCT) and depends on the recipient's bone marrow (BM) niche. A damaged niche contributes to poor graft function after alloSCT; however, the underlying mechanisms and the role of BM multipotent mesenchymal stromal cells (MSC) are ill-defined. Upon multivariate analysis in 732 individuals, we observed a reduced presence of proliferation-capable MSC in BM aspirates from patients (N = 196) who had undergone alloSCT. This was confirmed by paired analysis in 30 patients showing a higher frequency of samples with a lack of MSC presence post-alloSCT compared with pre-alloSCT. This reduced MSC presence was associated with reduced survival of patients after alloSCT and specifically with impaired graft function. Post-alloSCT MSC showed diminished in vitro proliferation along with a transcriptional antiproliferative signature, upregulation of epithelial-mesenchymal transition and extracellular matrix pathways, and altered impact on cytokine release upon contact with hematopoietic cells. To avoid in vitro culture bias, we isolated the CD146+/CD45-/HLA-DR- BM cell fraction, which comprised the entire MSC population. The post-alloSCT isolated native CD146+MSC showed a similar reduction in proliferation capacity and shared the same antiproliferative transcriptomic signature as for post-alloSCT colony-forming unit fibroblast-derived MSC. Taken together, our data show that alloSCT confers damage to the proliferative capacity of native MSC, which is associated with reduced patient survival after alloSCT and impaired engraftment of allogeneic hematopoiesis. These data represent the basis to elucidate mechanisms of BM niche reconstitution after alloSCT and its therapeutic manipulation.

Novel and Promising Strategies for Therapy of Post-Transplant Chronic GVHD

Despite the achievements that have increased viability after the transplantation of allogeneic hematopoietic stem cells (aHSCT), chronic graft-versus-host disease (cGVHD) remains the main cause of late complications and post-transplant deaths. At the moment, therapy alternatives demonstrate limited effectiveness in steroid-refractory illness; in addition, we have no reliable data on the mechanism of this condition. The lack of drugs of choice for the treatment of GVHD underscores the significance of the design of new therapies. Improved understanding of the mechanism of chronic GVHD has secured new therapy goals, and organized diagnostic recommendations and the development of medical tests have ensured a general language and routes for studies in this field. These factors, combined with the rapid development of pharmacology, have helped speed up the search of medicines and medical studies regarding chronic GVHD. At present, we can hope for success in curing this formidable complication. This review summarizes the latest clinical developments in new treatments for chronic GVHD.

Hematopoiesis reconstitution and anti-tumor effectiveness of Pai-Neng-Da capsule in acute leukemia patients with haploidentical hematopoietic stem cell transplantation

BACKGROUND

With the rapid development of haploidentical hematopoietic stem cell transplantation (haplo-HSCT), primary poor graft function (PGF) has become a life-threatening complication. Effective therapies for PGF are inconclusive. New Chinese patent medicine Pai-Neng-Da (PND) Capsule exerts dual effect in promoting hematopoiesis recovery and regulating immunity. Still, the application of PND capsule in hematopoietic stem cell transplantation, especially in the haplo-HSCT setting, has not yet been reported.

AIM

To evaluate the role of PND capsule in acute leukemia patients with haplo-HSCT.

METHODS

We retrospectively collected data of acute leukemia patients who underwent haplo-HSCT at the Affiliated People’s Hospital of Ningbo University between April 1, 2015 and June 30, 2020. Twenty-nine consecutive patients received oral PND capsule from the sixth day to the first month after haplo-HSCT were included in the PND group. In addition, 31 patients who did not receive PND capsule during haplo-HSCT were included in the non-PND group. Subsequently, we compared the therapeutic efficacy according to the western medical evaluation indexes and Chinese medical symptom scores, and the survival between the PND group and the non-PND group, using the chi-square test, Fisher’s exact test, and the Kaplan–Meier method.

RESULTS

The duration of platelet engraftment was shorter in the PND group than in the non-PND group (P = 0.039). The PND group received a lower frequency of red blood cells and platelet transfusions than the non-PND group (P = 0.033 and P = 0.035, respectively). In addition, PND capsule marginally reduced the rate of PGF (P = 0.027) and relapse (P = 0.043). After 33 (range, 4-106) months of follow-up, the 3-year relapse-free survival (P = 0.046) and progression-free survival (P = 0.049) were improved in the PND group than in the non-PND group. Also, the therapeutic efficacy of the PND group according to Chinese medical symptom scores was significantly better than that of the non-PND group (P = 0.022). Moreover, the adverse events caused by PND capsule were mild. Nevertheless, there were no significant differences in the duration of neutrophil engraftment, the risk of infection within 100 days after haplo-HSCT, the acute graft-versus-host disease, or the 3-year overall survival between the two groups.

CONCLUSION

PND capsule could promote hematopoiesis reconstitution, improve the therapeutic efficacy of Chinese medical symptom scores, present anti-tumor effectiveness, and prolong the survival of acute leukemia patients with haplo-HSCT.

The Incidence, Outcomes, and Risk Factors of Secondary Poor Graft Function in Haploidentical Hematopoietic Stem Cell Transplantation for Acquired Aplastic Anemia

Secondary poor graft function (sPGF) increases the risk of life-threatening complications after hematopoietic stem cell transplantation (HSCT). The incidence, clinical outcomes, and risk factors of sPGF have not been elucidated in haploidentical (haplo-) HSCT for acquired aplastic anemia (AA) patients. We retrospectively reviewed 423 consecutive AA patients who underwent haplo-HSCT between January 2006 and December 2020 and report a 3-year cumulative incidence of 4.62% (95% confidence interval [CI]: 3.92%-10.23%) of sPGF. While no primary PGF occurred. The median time to sPGF was 121 days (range 30-626 days) after transplantation. To clarify the risk factors for sPGF, 17 sPGF cases and 382 without PGF were further analyzed. Compared to patients without PGF, the 2-year overall survival was significantly poorer for sPGF patients (67.7% vs 90.8%, p =.002). Twelve sPGF patients were alive until the last follow-up, and 7 achieved transfusion independency. The multivariable analyses revealed that later neutrophil engraftment (OR 2.819, p=.049) and a history of refractory cytomegalovirus viremia (OR=7.038, p=.002) post-transplantation were associated with sPGF. There was weak evidence that a history of grade 3-4 acute graft-versus-host disease increased the risk of sPGF (p=.063). We advocated better post-transplantation strategies to balance the risk of immunosuppression and viral reactivation for haplo-HSCT in AA patients.

Clinical features, pathophysiology, and therapy of poor graft function post-allogeneic stem cell transplantation

Poor graft function (PGF), defined by the presence of multilineage cytopenias in the presence of 100% donor chimerism, is a serious complication of allogeneic stem cell transplant (alloSCT). Inducers or potentiators of alloimmunity such as cytomegalovirus reactivation and graft-versus-host disease are associated with the development of PGF, however, more clinical studies are required to establish further risk factors and describe outcomes of PGF. The pathophysiology of PGF can be conceptualized as dysfunction related to the number or productivity of the stem cell compartment, defects in bone marrow microenvironment components such as mesenchymal stromal cells and endothelial cells, or immunological suppression of post-alloSCT hematopoiesis. Treatment strategies focused on improving stem cell number and function and microenvironment support of hematopoiesis have been attempted with variable success. There has been limited use of immune manipulation as a therapeutic strategy, but emerging therapies hold promise. This review details the current understanding of the causes of PGF and methods of treatment to provide a framework for clinicians managing this complex problem.

Eltrombopag for Post-Transplant Poor Graft Function in East Asian Patients

Poor graft function (PGF) is a serious, potentially life-threatening complication of allogeneic hematopoietic stem cell transplantation. Eltrombopag has shown multilineage responses in patients with refractory severe aplastic anemia, supporting the idea that it may improve cytopenia in patients with PGF. This retrospective, single center analysis included 8 Korean patients receiving eltrombopag for PGF. Median interval between transplant and eltrombopag treatment was 73 days, and the median duration treatment was 3.5 weeks. With median maximum daily dose of 50 mg, the time to best response was 93 days. Median hemoglobin increased from 8.2 g/dL to 10.9 g/dL, platelet from 18.5 × 10⁹/L to 54 × 10⁹/L, and absolute neutrophil count from 1.25 × 10⁹/L to 3.32 × 10⁹/L. In conclusion, eltrombopag is a good option for PGF in Korean patients, even at a lower dose compared to western patients.

Comparable Outcomes in Acquired Severe Aplastic Anemia Patients With Haploidentical Donor or Matched Related Donor Transplantation: A Retrospective Single-Center Experience

Clinical data of patients with severe aplastic anemia (SAA) were retrospectively analyzed to evaluate the outcomes of haploidentical hematopoietic stem cell transplantation (HID-HSCT) with matched related sibling hematopoietic stem cell transplantation (MSD-HSCT) in complications and survivals. Thirty consecutive patients were enrolled in the study with a median follow-up of 50 months (range 4, 141), and the median age of the patients was 21 years (range 3, 49). All the patients achieved myeloid engraftment in the two cohorts. The cumulative incidences of platelet engraftment were 95.5 and 100% in HID cohort and MSD cohort, respectively. The median time for neutrophil and platelet recovery was 11 (range 9, 19) and 15 (range 10, 25) days in HID cohort, and 12 (range 10, 19) and 14 (range 8, 25) days in MSD cohort. The cumulative incidences of grade II–IV and grade III–IV acute graft vs. host disease (aGvHD) in HID cohort and in MSD cohort were 18.9 vs. 14.3% (p = 0.77) and 10.5 vs. 0% (p = 0.42), respectively. The cumulative incidences of chronic graft vs. host disease (cGvHD) was 22.7% in HID cohort and 25.5% in MSD cohort (p = 0.868). The 5-year overall survival (OS) rates and 5-year failure-free survival (FFS) rates in HID cohort and MSD cohort were 85.1 vs. 87.5% (p = 0.858), 80.3 vs. 87.5% (p = 0.635), respectively. The median time to achieve engraftment, cumulative incidence of aGvHD and cGvHD, and the 5-year OS and FFS rates were not significantly different between the two cohorts. We suggest that HID-HSCT might be a safety and effective option for SAA patients without a matched donor.

Haploidentical donor transplant is associated with secondary poor graft function after allogeneic stem cell transplantation: A single-center retrospective study

Background

Secondary poor graft function (sPGF) is a serious complication after allogeneic hematopoietic stem cell transplantation (allo‐HSCT) related to poor outcome. We aimed to retrospectively evaluate the morbidity and hazard elements of sPGF after allo‐HSCT.

Methods

Eight hundred and sixty‐three patients who achieved initial engraftment of both neutrophils and platelets were retrospectively reviewed in this study.

Results

Fifty‐two patients developed sPGF within 180 days post‐transplants, with the median onset time was 62 days (range, 34–121 days) post‐transplants. The overall cumulative incidence of sPGF within 180 days post‐transplantation was 6.0%, with 3.4%, 3.4%, and 10.1%, respectively, in matched sibling donor (MSD), matched unrelated donor (MUD), and haploidentical donor (HID) transplant (p < 0.0001). Multivariable analysis showed that HID (HID vs. MSD: hazard ratio [HR] 2.525, p = 0.004; HID vs. MUD: [HR] 3.531, p = 0.017), acute graft versus host disease (aGVHD) within +30 days ([HR] 2.323, p = 0.003), and cytomegalovirus (CMV) reactivation ([HR] 8.915, p < 0.0001) within +30 days post‐transplants were hazard elements of sPGF. The patients with sPGF had poorer survival than good graft function (51.7±8.1% vs. 62.9±1.9%, p < 0.0001). Our results also showed that only CMV reactivation was the hazard element for the development of PGF in HID transplant ([HR] 12.521 p < 0.0001).

Conclusion

HID transplant is also an independent hazard element of sPGF except for aGVHD and CMV reactivation.

Hematopoietic Dysfunction during Graft-Versus-Host Disease: A Self-Destructive Process?

Graft-versus-host disease (GvHD) is a major complication of allogeneic hematopoietic (stem) cell transplantation (HCT). Clinically, GvHD is associated with severe and long-lasting hematopoietic dysfunction, which may contribute to the high mortality of GvHD after HCT. During GvHD, excessive immune activation damages both hematopoietic stem and progenitor cells and their surrounding bone marrow niche, leading to a reduction in cell number and functionality of both compartments. Hematopoietic dysfunction can be further aggravated by the occurrence—and treatment—of HCT-associated complications. These include immune suppressive therapy, coinciding infections and their treatment, and changes in the microbiome. In this review, we provide a structured overview of GvHD-mediated hematopoietic dysfunction, including the targets in the bone marrow, the mechanisms of action and the effect of GvHD-related complications and their treatment. This information may aid in the identification of treatment options to improve hematopoietic function in patients, during and after GvHD.

Efficacy and cost analysis of eltrombopag in thrombocytopenia and poor graft function post allogeneic hematopoietic cell transplantation

Eltrombopag has shown efficacy in the treatment of thrombocytopenia and poor graft function (PGF) after allogeneic hematopoietic cell transplantation (HCT) in retrospective observational studies, but is not approved for this indication. The cost of this drug is also a major concern in publicly funded health care systems. We collected data about patients who received eltrombopag for thrombocytopenia or PGF after HCT. Post-HCT thrombocytopenia, PGF, and eltrombopag response were defined as per previously published criteria. Primary outcome was treatment efficacy and secondary outcome was cost comparison between estimated treatment cost prior to and after initiation of eltrombopag. Seventeen patients (males 70.6%; median age = 58) received eltrombopag. Isolated thrombocytopenia was present in 11.8% (n = 2) patients while PGF was present in 88.2% (n = 15) of patients. After 8 weeks of treatment at the maximum dose of 150 mg orally daily, overall response rate (ORR) was seen in 76.5% (13/17) of patients: complete response (CR) in 10/13 patients and partial response (PR) in 3/13 patients. The use of eltrombopag was associated with an overall decrease in the total weekly care costs (5021 vs 2,524 CA$; P = 0.04). Thus, Eltrombopag is an efficacious and possibly cost-effective therapy for thrombocytopenia and PGF after allogeneic HCT.

Use of eltrombopag for the treatment of poor graft function after hematopoietic stem cell transplantation in children

The main objective of this study was to determine whether Eltrombopag, a synthetic thrombopoietin receptor agonist, could improve peripheral blood counts in the three hematopoietic lineages and achieve transfusion independence in children with poor graft function (PGF) after allogenic hematopoietic stem cell transplantation (HSCT). Retrospective study of patients under 18 years who developed PGF post-HSCT in a large tertiary institution between January 2013 and March 2019. Out of 198 allogeneic HSCT, five patients met PGF criteria and were treated with eltrombopag. Median time from HSCT to eltrombopag initiation was 120 days. The median starting dose was 50 mg/day and the maximum dose reached was 75 mg/day. Median treatment duration was 9 months. Three patients achieved complete response and one partial response. The median dose among responders was 75 mg/day and the median time to response 8 weeks. Responses were sustained in three patients and two required a booster dose of CD34⁺ -selected cells from the original donor. None of the patients had to stop treatment due to adverse effects. The use of eltrombopag in children with PGF achieved responses in 80% of cases and demonstrated to be an effective and safe therapeutic option in pediatric patients with PGF.

Eltrombopag for the treatment of poor graft function following allogeneic stem cell transplant: a retrospective multicenter study

This retrospective study assessed the effectiveness of eltrombopag (EPAG), a thrombopoietin receptor agonist, in the treatment of poor graft function (PGF) following an allogeneic haemopoietic stem cell transplantation (HSCT). Complete response was defined as normalization of blood counts, whereas partial response was defined as transfusion independence. A total of 48 patients with full donor chimerism after HSCT, received EPAG for a median of 120 days (range 10-591). Patients with uni- bi- or tri-lineage cytopenia started treatment at a median of 95 days (range 17-877) after HSCT. The overall response rate was 75%: 24 patients had a complete response and 12 had a partial response. Positive predictors of response were an HLA-matched donor, a CD34⁺ dose at transplant > 4 × 10⁶/kg, and starting EPAG treatment at least 90 days after HSCT. Patients with more than one positive predictor had a response rate of 92% for the overall patient cohort and 94% for patients with tri-lineage cytopenia. One-year survival was 89% for complete responders, 60% for partial responders and 20% for non-responders (p = 0.0004). EPAG improves peripheral blood counts in patients with poor graft function following HSCT. Response to EPAG can be predicted and has a significant impact on survival.

Impaired Hematopoiesis after Allogeneic Hematopoietic Stem Cell Transplantation: Its Pathogenesis and Potential Treatments

Impaired hematopoiesis is a serious complication after allogeneic hematopoietic stem cell transplantation (allo-HSCT). Bone marrow aplasia and peripheral cytopenias arise from primary and secondary graft failure or primary and secondary poor graft function. Chimerism analysis is useful to discriminate these conditions. By determining the pathogenesis of impaired hematopoiesis, a timely and appropriate treatment can be performed. Hematopoietic system principally consists of hematopoietic stem cells and bone marrow microenvironment termed niches. Abnormality in hematopoietic stem and progenitor cells and/or abnormality in the relevant niches give rise to hematological diseases. Allo-HSCT is intended to cure each hematological disease, replacing abnormal hematopoietic stem cells and bone marrow niches with hematopoietic stem cells and bone marrow niches derived from normal donors. Therefore, treatment for graft failure and poor graft function after allo-HSCT is required to proceed based on determining the pathogenesis of impaired hematopoiesis. Recent progress in this area suggests promising treatment manipulations for graft failure and poor graft function.

Predictors of recovery following allogeneic CD34+-selected cell infusion without conditioning to correct poor graft function

Poor graft function is a serious complication following allogeneic hematopoietic stem cell transplantation. Infusion of CD34+-selected stem cells without pre-conditioning has been used to correct poor graft function, but predictors of recovery are unclear. We report the outcome of 62 consecutive patients who had primary or secondary poor graft function who underwent a CD34+-selected stem cell infusion from the same donor without further conditioning. Forty-seven of 62 patients showed hematological improvement and became permanently transfusion and growth factor-independent. In multivariate analysis, parameters significantly associated with recovery were shared CMV seronegative status for recipient/donor, the absence of active infection and matched recipient/donor sex. Recovery was similar in patients with mixed and full donor chimerism. Five -year overall survival was 74.4% (95% CI 59-89) in patients demonstrating complete recovery, 16.7% (95% CI 3-46) in patients with partial recovery and 22.2% (CI 95% 5-47) in patients with no response. In patients with count recovery, those with poor graft function in 1-2 lineages had superior 5-year overall survival (93.8%, 95% CI 82-99) than those with tri-lineage failure (53%, 95% CI 34-88). New strategies including cytokine or agonist support, or second transplant need to be investigated in patients who do not recover.

Rescue treatment with eltrombopag in refractory cytopenias after allogeneic stem cell transplantation

Background:

Patients with post-transplant cytopenias due to poor graft function or primary engraftment failure show poor prognosis with a high mortality rate mainly because of graft versus host disease (GVHD), infection and/or bleeding. Treatment options are scarce and a CD34+ stem cell boost or a second bone marrow transplantation may be required to restore adequate haematopoiesis.

Methods:

In the present study patients with primary engraftment failure (n = 1) and refractory poor graft function (n = 11) were treated with eltrombopag in a single centre. The reason for eltrombopag treatment was trilineage cytopenia in six patients, bilineage cytopenia in three patients and single lineage cytopenia in three patients. Eltrombopag was initiated at a median of 214 (range: 120–877) days after haematopoietic stem cell transplantation (HCST) and administered for a median time of 114 (range: 12 days to >490) days. In 8/12 patients eltrombopag was introduced at a dose of 75 mg/day and then increased to 150 mg/day after 1 week; 1 patient was given 50 mg eltrombopag per day, and 3 patients received 75 mg daily.

Results:

In 10/12 patients eltrombopag significantly enhanced blood count values and patients became transfusion independent. Once stable haematological response was obtained, treatment was tapered until final discontinuation in 9/10 responding patients. No grade 3 or 4 toxicities were observed. At time of last follow up, 3/12 patients were dead, 2 due to disease relapse, 1 due to GVHD and pneumonia. All patients except one maintained their complete response and remain transfusion independent at a median of 858 (range: 429–1119) days.

Conclusion:

These preliminary data confirm that eltrombopag is able to rescue multilineage haematopoiesis in patients with treatment-refractory cytopenias after allogeneic HSCT.

Acute Graft-versus-Host-Disease Other Than Typical Targets: Between Myths and Facts

Donor alloreactivity after allogeneic hematopoietic stem cell transplantation results in graft-versus-host reaction (GVHR) that may affect different organs. While skin, liver, and gastrointestinal tract are well-recognized targets of such alloreactivity early after transplant, commonly identified as acute graft-versus-host-disease (aGVHD), there is accumulating evidence from the literature that early GVHR may be directed also against other tissues. In particular, organs such as kidney, bone marrow, central nervous system, and lungs may be involved in patients experiencing aGVHD, but whether these sites represent targets or collateral damages of donor alloreactivity is matter of debate. This review summarizes the current knowledge, the potential applications, and the clinical relevance of GFHR in nontypical target organs during aGVHD. The objective of this article is to lay the basis for future efforts aiming at including these organs in grading and management of aGVHD.

Eltrombopag: Role in Cytopenias Following Hematopoietic Stem Cell Transplantation

Eltrombopag is a small molecule oral agonist of the thrombopoietin receptor. Initially used for improving thrombocytopenia in chronic immune thrombocytopenia (ITP), it was later found to be efficacious in various other etiologies of thrombocytopenia as well as inherited marrow failure syndromes. Lately, it has been used for thrombocytopenia and poor graft function after allogeneic hematopoietic stem cell transplantation (HSCT) without any severe adverse events. Although prospective evidence of the efficacy is limited, there are increasing reports on the safety and efficacy with Eltrombopag in post HSCT thrombocytopenia and poor graft function. This provides an exciting opportunity for further research to evaluate both efficacy and cost-effectiveness of the use of Eltrombopag in this scenario. Here we review the current evidence on the indications for the use of Eltrombopag in the post allogeneic hematopoietic stem cell transplant setting.

[Risk-factor analysis of poor graft function after allogeneic hematopoietic stem cell transplantation for severe aplastic anemia]

目的

探讨重型再生障碍性贫血（SAA）患者行异基因造血干细胞移植（allo-HSCT）后发生植入功能不良（PGF）的危险因素。

方法

回顾性分析111例行allo-HSCT的SAA患者临床资料及移植情况，采用Cox比例风险模型对可能影响PGF的因素进行单因素及多因素分析。

结果

在111例行allo-HSCT的SAA患者中，共有16例发生了PGF（14.4%）。多因素分析结果显示，非血缘供者（HR＝2.656，95%CI 1.204～5.858，P＝0.016）及移植前血清铁蛋白浓度（SF）>1 000 µg/L（HR＝3.170，95%CI 1.400～7.180，P＝0.006）是发生PGF的独立危险因素。

结论

非血缘供者及移植前SF>1 000 µg/L的患者移植后容易发生PGF。

Eltrombopag for post-transplant cytopenias due to poor graft function

Persistent cytopenia due to poor graft function (PoGF) is a relatively common complication which may affect up to 20% of patients undergoing allogeneic hematopoietic stem cell transplantation (HSCT). Treatment options for PoGF remain limited, and reinfusion of additional HSC is often the only way to rescue hematopoiesis. Here we describe a retrospective single-center experience with the thrombopoietin-mimetic agent eltrombopag for the treatment of PoGF. Thirteen patients have received eltrombopag for either PoGF (n = 12) or primary graft failure (n = 1). In the 12 PoGF patients eltrombopag was started at the median time of 79 days after HSCT, due to persistent thrombocytopenia, with concomitant anemia and neutropenia in 7 and 3 patients, respectively. The treatment was started at the dose of 50 mg per day, and eventually increased up to 150 mg in case of lack of response. Hematological response was seen in 7 patients, with 6 complete responses. Hematological responses were seen both in patients with evidence of immune-mediated pathophysiology, and with possible infectious/iatrogenic causes. In responding patients, eltrombopag was discontinued in 6/7 patients without further relapse. These results suggest that eltrombopag is safe and possibly effective in the setting of the treatment of PoGF, and pave the way for future prospective studies.

Poor graft function after allogeneic hematopoietic stem cell transplantation-an old complication with new insights☆

Poor graft function (PGF), characterized by pancytopenia, is a life-threatening complication following allogeneic hematopoietic stem cell transplantation (allo-HSCT). PGF has become a growing obstacle that contributes to high morbidity and mortality after allo-HSCT, especially with the increasing use of haploidentical allo-HSCT, and clinical management 81870139, is challenging. Emerging evidence demonstrates that the bone marrow (BM) microenvironment plays a crucial role in maintaining and regulating hematopoiesis. Recent prospective case-control studies demonstrated that impaired BM microenvironments are involved in the pathogenesis of PGF. Moreover, in vitro treatment with N-acetyl-L-cysteine, a reactive oxygen species scavenger, could enhance the defective hematopoietic stem cells by repairing the dysfunctional BM microenvironment of PGF patients. Consequently, a better understanding of the pathogenesis of PGF may guide effective therapy and eventually improve the prognosis of allo-HSCT. Here, based on new insights into the BM microenvironment in PGF patients, we provide an overview of the pathogenesis and promising treatment strategies for PGF patients.

Successful treatment of secondary poor graft function post allogeneic hematopoietic stem cell transplantation with eltrombopag

Poor graft function (PGF) is a life-threatening complication after allogeneic hematopoietic stem cell transplantation (allo-HSCT). Current treatment strategies include the use of growth factors, CD34⁺-selected stem cell boost, mesenchymal stem cell transfusion, and second allo-HSCT, but these treatments are not effective in all patients. Eltrombopag, an oral thrombopoietin receptor agonist, which showed promising results in severe aplasia anemia, may be an alternative choice for PGF patients. Therefore, we treated 12 patients who responded poorly to standard treatments for secondary PGF after allo-HSCT with eltrombopag. The median duration was 116 (35–1000) days from transplantation to PGF diagnosis and 59 (30–180) days from PGF diagnosis to eltrombopag treatment. Eltrombopag was started at a dose of 25 mg/d for 3 days and then increased to 50 or 75 mg/d. Median treatment duration was 8 (2–23) weeks. Ten patients (83.3%) responded to the treatment: 8 achieved complete response (CR), and the remaining 2 achieved partial response. In the 10 responding subjects, median platelet count was 18 (5–27) × 10⁹/L vs 74 (30–117) × 10⁹/L prior to and after treatment. Neutrophil count was 0.51 (0.28–0.69) × 10⁹/L vs 1.84 (0.78–4.90) × 10⁹/L. Hemoglobin was 88 (63–123) vs 101 (78–134) g/L. In the 8 patients who achieved CR, the time from eltrombopag initiation to achieving CR was 29 (10–49) days; the response lasted until the last follow-up in all 8 CR subjects (10–18 months). The 12-month overall survival rate was 83.3%. There was no treatment-related mortality and no evidence of cataract, thrombosis, or any other grade 3/4 toxicities.

Immunological Basis of Bone Marrow Failure after Allogeneic Hematopoietic Stem Cell Transplantation

Bone marrow failure (BMF) syndromes are severe complications of allogeneic hematopoietic stem cell transplantation (allo-HSCT). In this paper, we distinguish two different entities, the graft failure (GF) and the poor graft function (PGF), and we review the current understanding of the interactions between the immune and hematopoietic compartments in these conditions. We first discuss how GF occurs as the result of classical alloreactive immune responses mediated by residual host cellular and humoral immunity persisting after conditioning and prevented by host and donor regulatory T cells. We next summarize the current knowledge about the contribution of inflammatory mediators to the development of PGF. In situations of chronic inflammation complicating allo-HSCT, such as graft-versus-host disease or infections, PGF seems to be essentially the result of a sustained impairment of hematopoietic stem cells (HSC) self-renewal and proliferation caused by inflammatory mediators, such as interferon-γ (IFN-γ) and tumor necrosis factor-α, and of induction of apoptosis through the Fas/Fas ligand pathway. Interestingly, the production of inflammatory molecules leads to a non-MHC restricted, bystander inhibition of hematopoiesis, therefore, representing a promising target for immunological interventions. Finally, we discuss immune-mediated impairment of bone marrow microenvironment as a potential mechanism hampering hematopoietic recovery. Better understanding of immunological mechanisms responsible for BMF syndromes after allo-HSCT may lead to the development of more efficient immunotherapeutic interventions.

Mitochondrial reactive oxygen species regulate adipocyte differentiation of mesenchymal stem cells in hematopoietic stress induced by arabinosylcytosine

Objective

The increase in adipocytes induced by chemotherapeutic drugs may play a negative role in hematopoietic recovery. However, the mechanism underlying adipocyte differentiation of mesenchymal stem cells (MSCs) in hematopoietic stress is still unknown. Hence, the involvement of reactive oxygen species (ROS) in adipocyte differentiation under hematopoietic stress was investigated in vitro and in vivo.

Methods

The roles of cellular ROS in adipogenesis were investigated in vivo through an adipocyte hyperplasia marrow model under hematopoietic stress induced by arabinosylcytosine (Ara-C) and in vitro via adipocyte differentiation of human MSCs. ROS levels were detected using the CM-H₂DCFDA probe and Mito-SOX dye. Adipogenesis was evaluated by histopathology and oil red O staining, whereas detection of mRNA levels of antioxidant enzymes and adipogenesis markers was performed using quantitative real-time polymerase chain reaction analysis.

Results

ROS were found to play an important role in regulating adipocyte differentiation of MSCs by activating peroxisome proliferator-activated receptor gamma (PPARγ,) while the antioxidant N-acetyl-L-cysteine acts through ROS to inhibit adipocyte differentiation. The elevated ROS levels induced by Ara-C were caused by both over-generation of mitochondrial ROS and reduction of antioxidant enzymes (Cu/Zn Superoxide dismutase and catalase). Our findings suggest that a mitochondrial-targeted antioxidant could diminish adipocyte differentiation.

Acute GVHD after allogeneic hematopoietic transplantation affects early marrow reconstitution and speed of engraftment

Our aim was to study the influence of acute graft-versus-host disease (a-GVHD) on primary engraftment times after allogeneic transplantation. Primary engraftment and frequency of marrow granulocyte-macrophage colony-forming units and erythroid burst-forming units, at day +18, were studied in 126 allogeneic transplants. Patients were grouped according to the time when a-GVHD treatment with corticosteroids was started. The no-a-GVHD group are those who, during the first 3 months, had no need for a-GVHD treatment; the early-a-GVHD group are those who needed a-GVHD treatment within 19 days; and the postengraftment-a-GVHD group are those who were not on corticosteroid treatment at the time of engraftment but needed it after day +19. The no-a-GVHD group reached a neutrophil count (N) > 0.5 × 10(9)/L in a median of 17.8 days. The postengraftment-a-GVHD group reached N > 0.5 × 10(9)/L in a median of 21.4 days (p = 0.0003). The early-a-GVHD group had N > 0.5 × 10(9)/L in a median of +17.0 days (p = 0.23). When factors important for engraftment were studied in a multivariate analysis, postengraftment a-GVHD was a significant factor in delayed neutrophil and platelet engraftment. Both the early-a-GVHD and postengraftment-a-GVHD groups showed a significant reduction in frequency of granulocyte-macrophage colony-forming units and erythroid burst-forming units found in marrow at day +18. In conclusion, a-GVHD may influence early marrow reconstitution and is a relevant factor for primary myeloid and platelet engraftment.

Immunohematopoietic stem cell transplantation in Cape Town: a ten-year outcome analysis in adults

BACKGROUND AND OBJECTIVES

Immunohematopoietic stem cell transplantation has curative potential in selected hematologic disorders. Stem cell transplantation was introduced into South Africa in 1970 as a structured experimental and clinical program. In this report, we summarize the demography and outcome by disease category, gender, and type of procedure in patients older than 18 years of age who were seen from April 1995 to December 2002.

PATIENTS AND METHODS

This retrospective analysis included 247 individuals over 18 years of age for whom complete data were available. These patients received grafts mostly from peripheral blood with the appropriate stem cell population recovered by apheresis.

RESULTS

Patient ages ranged from 20 to 65 years with a median age of 42 years. There were 101 females and 146 males. There were no withdrawals and 63% survived to the end of the study. At 96 months of follow-up, a stable plateau was reached for each disease category. Median survival was 3.3 years (n=6, 14.6%) for acute lymphoblastic anemia, 3.1 years (n=44, 18%) for acute myeloid leukemia, 2.8 years (n=47, 19%) for chronic granulocytic leukemia, 2.8 years (n=71, 29%) for lymphoma, 1.5 years (n=23, 9%) for myeloma, 1.43 years (n=10, 4%) for aplasia, and 1.4 years (n=38, 15%) for a miscellaneous group comprising less than 10 examples each. Multivariate analysis showed that only diagnosis and age had a significant impact on survival, but these two variables might be interrelated. There was no significant difference in outcome by source of graft.

CONCLUSION

The results confirm that procedures carried out in a properly constituted and dedicated unit, which meets established criteria and strictly observes treatment protocols, generate results comparable to those in a First World referral center. Low rates of transplant-related mortality, rejection and graft-versus-host disease are confirmed, but the benefits cannot be extrapolated outside of academically oriented and supervised facilities.

Post-hematopoietic stem cell transplantion immune-mediated cytopenias

Immune-mediated cytopenias after allogeneic stem cell transplantation can be categorized as either alloimmune when host or donor immunity reacts against donor or host elements, respectively, or autoimmune when donor immunity reacts against donor hematopoietic tissue, owing to poorly understood mechanisms that result in severe impairment of central and peripheral tolerance. Immune cytopenias are manifested as monolineage or more rarely as bilineage cytopenias, and are usually mediated through humoral immune mechanisms. On the contrary, immune-mediated pancytopenia is a rare event with only few cases reported in the literature. The exact pathogenesis of immune pancytopenia is not well known although it is possible that cellular immunity may play a significant role. The importance of these syndromes lies in the fact that they can cause severe morbidity and mortality. Differential diagnosis from other causes of post-transplant pancytopenia is of extreme value because these disorders can respond to various treatment modalities.