Graft-versus-tumor effects after allogeneic hematopoietic cell transplantation with nonmyeloablative conditioning

Prospects and Potential for Chimerism Analysis after Allogeneic Hematopoietic Stem Cell Transplantation

Chimerism analysis after allogeneic hematopoietic stem cell transplantation serves to confirm engraftment, indicate relapse of hematologic malignancy, and attribute graft failure to either immune rejection or poor graft function. Short tandem repeat PCR (STR-PCR) is the prevailing method, followed by quantitative real-time PCR (qPCR), with detection limits of 1-5% and 0.1%, respectively. Chimerism assays using digital PCR or next-generation sequencing, both of which are more sensitive than STR-PCR, are increasingly used. Stable mixed chimerism is usually not associated with poor outcomes in non-malignant diseases, but recipient chimerism may foretell relapse of hematologic malignancies, so higher detection sensitivity may be beneficial in such cases. Thus, the need for and the type of intervention, e.g., immunosuppression regimen, donor lymphocyte infusion, and/or salvage second transplantation, should be guided by donor chimerism in the context of the feature and/or residual malignant cells of the disease to be treated.

Post-Transplantation Cyclophosphamide and Tacrolimus for Graft-versus-Host Disease Prevention after Allogeneic Hematopoietic Cell Transplantation from HLA-Matched Donors Has More Advantages Than Limitations

This study compared the efficacy of graft-versus-host disease (GVHD) prophylaxis with post-transplantation cyclophosphamide (PTCy) and tacrolimus (Tac) versus other regimens in 272 adults undergoing peripheral blood (PB) allogeneic hematopoietic cell transplantation (allo-HCT) from HLA-matched donors. Of these 272 patients, 95 (34.9%) received PTCy/Tac. The times to neutrophil and platelet engraftment were longer in the PTCy/Tac group (20 days versus 16 days for neutrophils and 19 days versus 12 days for platelets). The day +30 cumulative incidence (CuI) of bacterial bloodstream infection was higher in the PTCy/Tac group (43.2% versus 13.0%; P < .001). The CuIs of grade II-IV and grade III-IV acute GVHD (aGVHD) at day +180 were 14.7% and 4.2%, and the CuI of moderate/severe cGVHD at 2 years was 2.4% in the PTCy/Tac group and 41.8% (hazard ratio [HR], .29; P < .001), 15.8%, (HR, .24; P = .007), and 47.0% (HR, .05; P < .001), respectively, in the no-PTCy group. The duration of immunosuppression was shorter in patients receiving PTCy/Tac (6.2 months versus 9.0 months; P < .001). PTCy/Tac patients had higher OS (2 years: 74.3% versus 60.9%; HR, .54; P = .012), lower NRM (2 years: 8.6% versus 15.8%; HR, .54; P = .11), comparable CuI of relapse (2 years: 26.0% versus 24.4%; HR, 1.03; P = .89), and higher GRFS (2 years: 59.1% versus 16.7%; HR, .32; P < .001). Using PTCy/Tac in HLA-matched PB allo-HCT improved transplantation outcomes at out institution compared with previous prophylactic regimens, including a higher probability of survival despite more delayed engraftment and a higher rate of bacterial infection.

ACR-ARS Practice Parameter for the Performance of Total Body Irradiation

OBJECTIVES

This practice parameter was revised collaboratively by the American College of Radiology (ACR) and the American Radium Society (ARS). This practice parameter provides updated reference literature regarding both clinical-based conventional total body irradiation and evolving volumetric modulated total body irradiation.

METHODS

This practice parameter was developed according to the process described under the heading The Process for Developing ACR Practice Parameters and Technical Standards on the ACR website ( https://www.acr.org/Clinical-Resources/Practice-Parameters-and-Technical-Standards ) by the Committee on Practice Parameters-Radiation Oncology of the ACR Commission on Radiation Oncology in collaboration with the ARS.

RESULTS

This practice parameter provides a comprehensive update to the reference literature regarding conventional total body irradiation and modulated total body irradiation. Dependence on dose rate remains an active area of ongoing investigation in both the conventional setting (where instantaneous dose rate can be varied) and in more modern rotational techniques, in which average dose rate is the relevant variable. The role of imaging during patient setup and the role of inhomogeneity corrections due to computer-based treatment planning systems are included as evolving areas of clinical interest notably surrounding the overall dose inhomogeneity. There is increasing emphasis on the importance of evaluating mean lung dose as it relates to toxicity during high-dose total body irradiation regimens.

CONCLUSIONS

This practice parameter can be used as an effective tool in designing and evaluating a total body irradiation program that successfully incorporates the close interaction and coordination among the radiation oncologists, medical physicists, dosimetrists, nurses, and radiation therapists.

Allogeneic transplantation of bone marrow versus peripheral blood stem cells from HLA-identical relatives in patients with myelodysplastic syndromes and oligoblastic acute myeloid leukemia: a propensity score analysis of a nationwide database

Bone marrow (BM) and granulocyte colony-stimulating factor-mobilized peripheral blood stem cells (PBSC) are used as grafts from HLA-identical-related donors for adults with myelodysplastic syndrome (MDS). To assess the impact of graft sources on post-transplant outcomes in MDS patients, we conducted a retrospective analysis of a nationwide database. A total of 247 and 280 patients underwent transplantation with BM and PBSC, respectively. The inverse probability of treatment weighting (IPTW) methods revealed that overall survival (OS) was comparable between BM and PBSC (P = .129), but PBSC transplantation was associated with worse graft-versus-host disease (GVHD)-free/relapse-free survival (GRFS) (hazard rate [HR], 1.24; 95% confidence intervals [CIs], 1.00-1.53; P = 0.049) and chronic GVHD-free and relapse-free survival (CRFS) (HR, 1.29; 95% CIs, 1.13-1.73; P = 0.002) than BM transplantation. In the propensity score matched cohort (BM, n = 216; PBSC, n = 216), no significant differences were observed in OS and relapse; 3-year OS rates were 64.7% and 60.0% (P = 0.107), while 3-year relapse rates were 27.1% and 23.5% (P = 0.255) in BM and PBSC, respectively. Three-year GRFS rates (36.6% vs. 29.2%; P = 0.006), CRFS rate (37.7% vs. 32.5%; P = 0.003), and non-relapse mortality rates (13.9% vs. 21.1%; P = 0.020) were better in BM than in PBSC. The present study showed that BM transplantation provides a comparable survival benefit with PBSC transplantation and did not identify an enhanced graft-versus-MDS effect to reduce the incidence of relapse in PBSC transplantation.

Post-transplant cyclophosphamide prevents xenogeneic graft-versus-host disease while depleting proliferating regulatory T cells

Graft-versus-host disease (GVHD) remains a serious limitation of allogeneic hematopoietic cell transplantation (allo-HCT). While post-transplant administration of cyclophosphamide (PTCy) is increasingly used as GVHD prophylaxis, its precise mechanisms of action and its impact on graft-versus-leukemia effects have remained debated. Here, we studied the mechanisms of xenogeneic GVHD (xGVHD) prevention by PTCy in different humanized mouse models. We observed that PTCy attenuated xGVHD. Using flow cytometry and single-cell RNA-sequencing, we demonstrated that PTCy depleted proliferative CD8⁺ and conventional CD4⁺ T cells but also proliferative regulatory T cells (Treg). Further, T-cell receptor β variable region sequencing (TCRVB) analyses demonstrated that highly xenoreactive T-cell clones were depleted by PTCy. Although Treg frequencies were significantly higher in PTCy-treated than in control mice on day 21, xGVHD attenuation by PTCy was not abrogated by Treg depletion. Finally, we observed that PTCy did not abrogate graft-versus-leukemia effects.

Early relapse prediction after allogeneic hematopoietic stem cell transplantation for acute lymphoblastic leukemia (ALL) using lineage-specific chimerism analysis

Relapse is a major cause of treatment failure after hematopoietic stem cell transplantation (HSCT) for acute leukemia. Here, we report a monocentric retrospective study of all HSCTs for B cell acute lymphoblastic leukemia (ALL) performed during the years 2005-2021 (n = 138, including 51 children), aiming to identify the optimal use of lineage-specific recipient-donor chimerism analysis for prediction of relapse. In adults, relapse was associated with increased recipient chimerism in CD3+ bone marrow cells sampled at least 30 days before a relapse. Relapse could be predicted with a sensitivity of 73% and a specificity of 83%. Results were similar for children but with a higher recipient chimerism cutoff. Additionally, adults that had at least one chimerism value <0.12% in CD3+ peripheral blood cells within the first 60 days after HSCT had 89% probability of being relapse-free after 2-years compared to 64%. Results were similar for children but again necessitating a higher chimerism cutoff. These results suggest that high-sensitive lineage-specific chimerism analysis can be used for (1) early ALL relapse prediction by longitudinal chimerism monitoring in CD3+ bone marrow cells and (2) relapse risk stratification by analyzing CD3+ blood cells early post-HSCT.

Autologous Hematopoietic Stem Cell Transplantation in Multiple Sclerosis Patients: Monocentric Case Series and Systematic Review of the Literature

Multiple sclerosis (MS) is a chronic, inflammatory and immune-mediated disease of the central nervous system (CNS), commonly affecting young adults and potentially associated with life-long disability. About 14 disease-modifying treatments (DMTs) are currently approved for the treatment of MS. However, despite the use of highly effective therapies, some patients exhibit a highly active disease with an aggressive course from onset and a higher risk of long-term disability accrual. In the last few years, several retrospective studies, clinical trials, meta-analyses and systematic reviews have investigated autologous hematopoietic stem cell transplantation (AHSCT) as a possible therapeutic option in order to address this unmet clinical need. These studies demonstrated that AHSCT is a highly efficacious and relatively safe therapeutic option for the treatment of highly active MS. Particularly, over recent years, the amount of evidence has grown, with significant improvements in the development of patient selection criteria, choice of the most suitable transplant technique and clinical experience. In this paper, we present six patients who received AHSCT in our MS center and we systematically reviewed recent evidence about the long-term efficacy and safety of AHSCT and the placement of AHSCT in the rapidly evolving therapeutic armamentarium for MS.

Intestinal outcome of bone marrow transplantation for monogenic inflammatory bowel disease

BACKGROUND

Some monogenic inflammatory bowel diseases (IBDs) are known to be refractory to conventional treatments. Although allogeneic hematopoietic stem-cell transplantation (allo-HSCT) has become a curative therapeutic option for certain monogenic IBDs, its effectiveness regarding endoscopic improvements has not been clarified.

METHODS

The clinical course and endoscopic findings of patients with monogenic IBDs who were treated with allo-HSCT between December 2017 and November 2018 at the National Center for Child Health and Development, were retrospectively reviewed. The clinical disease activity was assessed using the weighted Pediatric Crohn's Disease Activity Index (wPCDAI) and the endoscopic finding was evaluated using the Simple Endoscopic Score for Crohn's Disease (SES-CD). Clinical remission was defined as a wPCDAI <10 and endoscopic remission was defined as an SES-CD of 2 or less.

RESULTS

Four patients with severe monogenic IBDs, including three with X-linked inhibitors of apoptosis protein (XIAP) deficiency and one with interleukin-10 signaling defect, were treated with allo-HSCT with reduced-intensity conditioning. In four patients, the maximum scores of wPCDAI and SES-CD before allo-HSCT ranged from 67.5 to 120 and 20 to 34, respectively. After allo-HSCT, all four patients showed a significant improvement in intestinal inflammation and achieved both clinical and endoscopic remission. Although patients with XIAP deficiency presented with post-transplant hemophagocytic lymphohistiocytosis and a relatively late engraftment, all patients achieved prolonged clinical remission, and IBD medications were successfully discontinued in all patients.

CONCLUSION

Allo-HSCT for monogenic IBD resulted in complete clinical resolution with endoscopically confirmed mucosal healing.

Outcomes of adults with lymphoma treated with nonmyeloablative TLI-ATG and radiation boost to high risk or residual disease before allogeneic hematopoietic cell transplant

We evaluated the impact on survival of antithymocyte globulin conditioning (TLI-ATG) with radiation (RT) boost to high risk or residual disease before allogeneic hematopoietic cell transplant (allo-HCT) for adults with lymphoma (excluding mycosis fungoides and low-grade NHL other than SLL/CLL). Of 251 evaluable patients, 36 received an RT boost within 3 months of allo-HCT at our institution from 2001 to 2016. At the time of TLI-ATG, patients who received boost vs no boost had a lower rate of CR (11% vs 47%, p = 0.0003), higher rates of bulky disease (22% vs 4%, p < 0.0001), extranodal disease (39% vs 5%, p < 0.0001), and positive PET (75% vs 28%, p < 0.00001). In the boost group, the median (range) largest axial lesion diameter was 5.2 cm (1.8-22.3). Median follow-up was 50.2 months (range: 1-196). There was no significant difference in OS, time to recurrence, or time to graft failure with vs without boost. A trend toward higher percent donor CD3⁺ chimerism was seen with vs without boost (p = 0.0819). The worst boost-related toxicity was grade 2 dermatitis. RT boost may help successfully mitigate the risk of high risk or clinically evident residual disease in adults with lymphoma undergoing allo-HCT.

Use of chimerism analysis after allogeneic stem cell transplantation: Belgian guidelines and review of the current literature

Background: Allogeneic hematopoietic stem cell transplantation (HSCT) is a curative treatment option in both adult and pediatric patients with malignant and non-malignant hematological diseases.  Chimerism analysis, which determines the donor or recipient origin of hematopoietic cells in HSCT recipients, is an essential aspect of post-HSCT follow-up.Objectives: To review the current literature and develop Belgian consensus guidelines for the use of chimerism analysis in the standard of care after allogeneic HSCT.Methods: Non-systematic review of the literature in consultancy with the members of the BHS transplantation committee.Results: Clinical application with regards to prediction of graft failure or relapse as well as cell source are reviewed. A consensus guideline on the use of chimerism analysis after HSCT is presented.Conclusion: Monitoring of the dynamics or kinetics of a patient's chimerism status by serial analysis at fixed time points, as well as on suspicion of relapse or graft failure, is needed to monitor engraftment levels, as well as disease control and possible relapse.

Retrospective comparison of hematopoietic stem cell transplantation following reduced-intensity conditioning with fludarabine/low-dose melphalan plus 4 Gy TBI versus fludarabine/ busulfan plus 4 Gy TBI

Fludarabine with intravenous busulfan (6.4 mg/kg; FB2) and fludarabine with intermediate-dose melphalan (140 mg/m²; FM140) are the most widely used reduced-intensity conditioning (RIC) regimens for allogeneic hematopoietic stem cell transplantation. FM140 generally has a lower relapse rate and higher non-relapse mortality (NRM), resulting in overall survival (OS) comparable to that seen with FB2. To evaluate the effect of reducing the melphalan dose, we retrospectively compared transplant outcomes in 156 patients who received FB2 (n = 103) or FM80 (n = 53) at our center (median age: 63 years; range 27-72 years). All patients received 4-Gy total body irradiation. Three-year OS, the cumulative incidence of relapse, and NRM were comparable between groups (FB2 vs. FM80, 58% vs. 47%, p = 0.24; 30% vs. 36%, p = 0.57; 17% vs. 21%, p = 0.44, respectively). There was no significant difference in the cumulative incidence of graft-versus-host disease (GVHD) at day 100, chronic GVHD at 3 years, or the 3-year GVHD-free/relapse-free survival rate. In the high-risk disease group, patients receiving FM80 tended to have lower 3-year OS (FB2 vs. FM80, 48% vs. 17%, p = 0.06). In summary, transplant outcomes following FB2 or FM80 were comparable except in patients with high-risk disease.

Mixed T cell lineage chimerism in acute leukemia/MDS using pre-emptive donor lymphocyte infusion strategy-Is it prognostic?-a single-center retrospective study

Pre-emptive DLI (pDLI) is an effective strategy in lowering the risk of relapse without significantly increasing the risk of graft-versus-host disease (GVHD) in the case of T cell lineage mixed chimerism (MC) post allogeneic transplant in hematological malignancies. Many patients, however, fail to receive timely pDLI and have dismal outcomes, which are not taken into consideration. We compared long-term outcomes of 106 patients having T cell MC after day 60 and undergoing allogeneic stem cell allograft for acute leukemia from an unrelated donor (UD), with 111 patients having complete chimerism (CC). Fifty-three (56%) patients received prophylactic pDLI. Thirty-six patients (67%) had a response (RR), 17 (33%) had no response (NR), and fifty-two (54%) did not receive any pDLI (ND). OS was better in MC group as compared to CC (54% vs 43%, p = 0.04), mainly due to reduction in NRM (14% vs 25%, p = 0.05), and all grade acute and chronic GVHD. Within the MC group, response to pDLI was the only significant factor predicting OS, DFS, and relapses with NR and ND having unfavorable outcomes as compared to RR (p = 0.001). T cell MC in patients undergoing UD allografts with alemtuzumab is no longer an adverse prognostic factor, as compared to patients having CC, after timely implementation of pDLI.

Itacitinib prevents xenogeneic GVHD in humanized mice

We assessed the impact of the Janus Kinase (JAK) 1 inhibitor itacitinib on xenogeneic graft-versus-host disease (xGVHD). XGVHD was induced by i.v. injection 20 × 10⁶ human peripheral blood mononuclear cells (hPBMC) in NSG mice on day 0. Itacitinib (3 mg, ≈120 mg/kg) or methylcellulose was administered by force-feeding twice a day from day 3 to day 28. Mice were followed for xGVHD score and survival. In addition, human T-cell engraftment and as well as human T-cell subtypes were monitored in blood on days 14, 21, and 28 after transplantation. We observed that itacitinib-treated mice had significantly longer survival than control mice (median 45 versus 33 days; P < 0.001). Further, they also had lower absolute numbers of human CD4⁺ T cells on days 21 and 28 after transplantation as well as of human CD8⁺ T cells on days 14, 21, and 28 after transplantation. In addition, itacitinib-treated mice had higher frequencies of human regulatory T cells (Treg) on days 21 and 28 after transplantation. In summary, our data indicate that itacitinib decreases human T-cell engraftment, increases Treg frequencies and attenuates xGVHD in NSG mice transplanted with hPBMC.

Uncovering the multifaceted roles played by neutrophils in allogeneic hematopoietic stem cell transplantation

Allogeneic hematopoietic stem cell transplantation (alloHSCT) is a life-saving procedure used for the treatment of selected hematological malignancies, inborn errors of metabolism, and bone marrow failures. The role of neutrophils in alloHSCT has been traditionally evaluated only in the context of their ability to act as a first line of defense against infection. However, recent evidence has highlighted neutrophils as key effectors of innate and adaptive immune responses through a wide array of newly discovered functions. Accordingly, neutrophils are emerging as highly versatile cells that are able to acquire different, often opposite, functional capacities depending on the microenvironment and their differentiation status. Herein, we review the current knowledge on the multiple functions that neutrophils exhibit through the different stages of alloHSCT, from the hematopoietic stem cell (HSC) mobilization in the donor to the immunological reconstitution that occurs in the recipient following HSC infusion. We also discuss the influence exerted on neutrophils by the immunosuppressive drugs delivered in the course of alloHSCT as part of graft-versus-host disease (GVHD) prophylaxis. Finally, the potential involvement of neutrophils in alloHSCT-related complications, such as transplant-associated thrombotic microangiopathy (TA-TMA), acute and chronic GVHD, and cytomegalovirus (CMV) reactivation, is also discussed. Based on the data reviewed herein, the role played by neutrophils in alloHSCT is far greater than a simple antimicrobial role. However, much remains to be investigated in terms of the potential functions that neutrophils might exert during a highly complex procedure such as alloHSCT.

High proportion of terminally differentiated regulatory T cells after allogeneic hematopoietic stem cell transplantation

It is now well-established that regulatory T cells (Treg) represent a heterogeneous group of CD4⁺ T cells. Previous studies have demonstrated that Treg homeostasis was impacted by allogeneic hematopoietic cell transplantation (allo-HCT) and particularly so in patients with chronic graft-versus-host disease (GVHD). Here, we first assessed the ability of various Treg subsets to phosphorylate STAT5 in response to IL-2 or IL-7 stimulation in vitro. We then compared the frequencies of different Treg subtypes in healthy controls as well as in allo-HCT patients with or without chronic GVHD. The highest phosphorylated STAT5 (pSTAT5) signal in response to IL-2 was observed in the CD45RO⁺CD26^-CD39⁺HLA-DR⁺ Treg fraction. In contrast, naive Treg were mostly less susceptible to IL-2 stimulation in vitro. Following IL-7 stimulation, most Treg subpopulations upregulated pSTAT5 expression but to a lesser extent than conventional T cells. Compared to healthy controls, allo-HCT patients had lower frequencies of the naive CD45RA^brightCD26⁺ Treg subpopulation but higher frequencies of the most differentiated memory CD45RO⁺CD26^-CD39⁺ Treg subpopulations. Further, unbiased analysis revealed that six Treg clusters characterized by high expression of CD25, HLA-DR, and ICOS were significantly more frequent in patients with no or with limited chronic GVHD than in those with moderate/severe chronic GVHD.

Comparison of Tacrolimus and Cyclosporine Combined With Methotrexate for Graft Versus Host Disease Prophylaxis After Allogeneic Hematopoietic Cell Transplantation

BACKGROUND

After patients receive hematopoietic stem cell transplantation (HSCT), both cyclosporine (CsA) and tacrolimus (TAC) in combination with methotrexate (MTX) are recommended as the standard prophylaxis strategy for graft versus host disease (GVHD) by the European Group of Blood and Marrow Transplantation. However, the advantage of TAC combined with MTX lacks conclusive evidence.

METHODS

We searched online databases for studies comparing CsA + MTX and TAC + MTX in patients who received HSCT. The odds ratio (OR) and 95% confidence interval (CI) were applied to compare the pooled data.

RESULTS

We found a significant reduction in the grade II to IV acute GVHD (aGVHD) rate (OR, 0.42; CI, 0.28-0.61; P < 0.00001), grade III to IV aGVHD rate (OR, 0.59; CI, 0.38-0.92; P = 0.02), chronic GVHD rate (OR, 0.79; CI, 0.62-1.00; P = 0.05), and nonrelapse mortality rate (OR, 0.62; CI, 0.40-0.95; P = 0.03) and an increase in the overall survival (OS) rate (only in those received from unrelated donor) (OR, 1.30; CI, 1.15-1.48; P < 0.0001) in the TAC + MTX group. Similar outcomes occurred for the relapse rate and disease-free survival rate in both groups.

CONCLUSIONS

TAC + MTX has a superior effect in the prevention of aGVHD in patients who received HSCT and further prolongs the OS in patients who received from unrelated donor transplants. CsA + MTX prolongs the OS in patients who received HSCT from HLA-identical sibling donors. The leukemic relapse and disease-free survival rate were not different between the 2 regimens. Thus, we conclude that TAC + MTX was superior to CsA + MTX, especially for HSCT patients with nonmalignant disorders. Further studies are still required to evaluate the effect of TAC or CsA combined with other suppressors in the treatment regimen following HSCT.

Better leukemia-free survival with allogeneic than with autologous HCT in AML patients with isolated trisomy 8: a study from the ALWP of the EBMT

The indication for performing an allogeneic hematopoietic stem cell transplantation (allo-HCT) in patients with isolated trisomy 8 AML in first complete remission (CR) is still debated. Here, we compared outcomes of such patients given either allo-HCT or autologous (auto)-HCT. Inclusion criteria consisted of adult patients with de novo AML, isolated trisomy 8, first HCT between 2000 and 2018, CR1 at transplantation, and either auto-HCT or allo-HCT with a HLA-identical sibling donor (MSD) or a 10/10 HLA-matched unrelated donor (UD 10/10). A total of 401 patients met the inclusion criteria. They underwent an auto-HCT (n = 81), allo-HCT with a MSD (n = 186) or allo-HCT with a 10/10 UD (n = 134). At 3 years, relapse incidence, nonrelapse mortality and leukemia-free survival (LFS) were 59%, 5%, and 37%, respectively, in auto-HCT recipients; 31% (P < 0.001), 14% (P = 0.04), and 55% (P = 0.033), respectively, in MSD recipients and 29% (P < 0.001), 13% (P = 0.15), and 59% (P = 0.03), respectively, in UD 10/10 recipients. In multivariate analysis, in comparison to auto-HCT, MSD and UD 10/10 were associated with a lower risk of relapse (HR = 0.47, P < 0.001 and HR = 0.40, P < 0.001, respectively) translating to better LFS (HR = 0.69, P = 0.04 and HR = 0.60, P = 0.03, respectively). There was also a similar trend for overall survival (HR = 0.73, P = 0.12 and HR = 0.65, P = 0.08).

Nonmyeloablative TLI-ATG conditioning for allogeneic transplantation: mature follow-up from a large single-center cohort

Nonmyeloablative total lymphoid irradiation and antithymocyte globulin (TLI-ATG) conditioning is protective against graft-versus-host disease (GVHD), while retaining graft-versus-tumor activity across various hematologic malignancies. We report our comprehensive experience using TLI-ATG conditioning in 612 patients with hematologic malignancies who underwent allogeneic transplantation at Stanford University from 2001 to 2016. All patients received granulocyte colony-stimulating factor-mobilized peripheral blood grafts and cyclosporine and mycophenolate mofetil for GVHD prophylaxis. The median age was 60 years (range, 21-78), with a median follow-up of 6.0 years (range, 1.0-16.4). Common diagnoses included acute myeloid leukemia (AML; n = 193), myelodysplastic syndrome (MDS; n = 94), chronic lymphocytic leukemia (CLL; n = 80), non-Hodgkin lymphoma (NHL; n = 175), and Hodgkin lymphoma (HL; n = 35). Thirty-four percent of patients had a comorbidity index ≥3, 30% had a high to very high disease risk index, and 56% received unrelated donor grafts, including 15% with HLA-mismatched donors. Ninety-eight percent underwent transplant in the outpatient setting, and 57% were never hospitalized from days 0 through 100. The 1-year rates of nonrelapse mortality (NRM), grade II-IV acute GVHD, and extensive chronic GVHD were 9%, 14%, and 22%, respectively. The 4-year estimates for overall and progression-free survival were 42% and 32% for AML, 30% and 21% for MDS, 67% and 43% for CLL, 68% and 45% for NHL, and 78% and 49% for HL. Mixed chimerism correlated with the risk of relapse. TLI-ATG conditioning was well tolerated, with low rates of GVHD and NRM. Durable remissions were observed across hematologic malignancies, with particularly favorable outcomes for heavily pretreated lymphomas. Several efforts are underway to augment donor chimerism and reduce relapse rates while maintaining the favorable safety and tolerability profile of this regimen.

Incidence, Risk Factors, and Outcomes of Chronic Graft-versus-Host Disease in Pediatric Patients with Hematologic Malignancies after T Cell-Replete Myeloablative Haploidentical Hematopoietic Stem Cell Transplantation with Antithymocyte Globulin/Granulocyte Colony-Stimulating Factor

The specific description, risk factors, and outcomes of chronic graft-versus-host disease (cGVHD) in pediatric patients with hematologic malignancies after T cell-replete (TCR) myeloablative haploidentical hematopoietic stem cell transplantation (haplo-HSCT) with antithymocyte globulin (ATG)/granulocyte colony-stimulating factor (G-CSF) have not been previously well described. We retrospectively analyzed the incidence, risk factors, and outcomes of cGVHD documented according to the 2014 National Institutes of Health consensus criteria (NIH-CC) in 292 consecutive pediatric patients with hematologic malignancies after TCR myeloablative haplo-HSCT with ATG/G-CSF between January 2015 and December 2017. A total of 170 patients experienced cGVHD. The 3-year cumulative incidence of total cGVHD and mild, moderate, and severe cGVHD was 57.9%, 27.5%, 18.8%, and 11.9%, respectively. Multivariate analysis showed that acute GVHD (aGVHD) grade II-IV (hazard ratio, 1.578; P = .002) was an independent risk factor for cGVHD. Compared to patients without cGVHD, patients with cGVHD demonstrated a lower 3-year relapse (17.6% versus 27.2%; P = .009), a similar 3-year nonrelapse mortality (NRM) (5.9% versus 5.4%; P = .79), and better 3-year disease-free survival (DFS) (77.8% versus 66.9%; P = .007) and overall survival (OS) (81.3% versus 68.6%; P = .001), particularly those with mild or moderate cGVHD; however, no significant impact of severe cGVHD on relapse, NRM, DFS, or OS was seen. In conclusion, the incidence of severe cGVHD in pediatric patients with hematologic malignancies after TCR myeloablative haplo-HSCT with ATG/G-CSF was acceptable. Previous aGVHD grade II-IV was a risk factor for the occurrence of cGVHD. Only mild or moderate cGVHD was associated with a lower risk of relapse, translating into improved DFS and OS in pediatric patients with hematologic malignancies after TCR myeloablative haplo-HSCT with ATG/G-CSF.

Allogeneic peripheral blood stem cell transplantation with anti-thymocyte globulin versus allogeneic bone marrow transplantation without anti-thymocyte globulin

We compared severe graft-versus-host-disease (GvHD) free and relapse-free survival and other transplantation outcomes of acute myeloid leukemia (AML) patients given bone marrow (BM) without anti-thymocyte globulin (ATG) versus peripheral blood stem cells (PBSC) with ATG after myeloablative conditioning. In the cohort of patients receiving grafts from a human leukocyte antigen (HLA)-matched sibling donor, patients given PBSC with ATG (n=1,021) and those given BM without ATG (n=1,633) presented comparable severe GvHD-free relapse-free survival (GRSF)(hazard ratio [HR]=0.9, 95% confidence interval [CI]: 0.8-1.1, P=0.5) and overall survival (HR=1.0, 95% CI: 0.8-1.2, P=0.8). They had however, a lower incidence of chronic GvHD (cGvHD) (HR=0.7, 95% CI: 0.6-0.9, P=0.01). In the cohort of patients receiving grafts from HLA-matched unrelated donor , patients given PBSC with ATG (n=2,318) had better severe GvHD-free and relapse-free survival (GRFS) than those given BM without ATG (n=303) (HR=0.8, 95% CI: 0.6-0.9, P=0.001). They also had a lower incidence of cGvHD (HR=0.6, 95% CI: 0.5-0.8, P=0.0006) and better overall survival (HR=0.8, 95% CI: 0.6-1.0, P=0.04). In summary, these data suggest that PBSC with ATG results in comparable (in the case of sibling donor) or significantly better (in the case of unrelated donor) severe GRFS than BM without ATG in patients with AML in complete remission receiving grafts after myeloablative conditioning.

Effect of graft-versus-host disease on outcomes after pediatric single cord blood transplantation

The effect of GVHD on transplant outcomes after unrelated cord blood transplantation (UCBT) is not yet fully understood. Pediatric patients aged 0-15 years with acute leukemia or myelodysplastic syndrome who underwent their first UCBT (n = 740) were selected from the Japanese registry. Fifty percent of the patients received a UCB unit containing more than 5.0 × 10⁷/kg total nucleated cells. The occurrence of grade III-IV acute GVHD was associated with a higher risk of non-relapse mortality (NRM, hazard ratio [HR] 4.07, P < 0.001) compared with no acute GVHD. Grade I-II acute GVHD was not associated with NRM. The occurrence of grade I-II or grade III-IV acute GVHD was not associated with a relapse risk. These findings showed that grade I-II acute GVHD carried no survival benefit and grade III-IV acute GVHD had an adverse effect (HR 1.68, P = 0.007). The occurrence of limited chronic GVHD was associated with a low risk of overall mortality (HR 0.60, P = 0.045). Severe acute GVHD should be prevented because of its association with high overall mortality and NRM in pediatric single UCBT. Mild acute GVHD provides no overall benefit. Mild chronic GVHD may be beneficial for survival.

Role of pretransplant anti-thymocyte globulin in matched sibling donor stem cell transplantation after reduced intensity conditioning for myelodysplastic syndrome

OBJECTIVE

We investigated the role of anti-thymocyte globulin (ATG; Thymoglobulin) in matched sibling donor hematopoietic stem cell transplantation (MSD-HSCT) after reduced intensity conditioning (RIC) in myelodysplastic syndrome (MDS).

METHODS

Forty-seven patients with 10 mg/kg ATG (ATG group; median age 53 years) and 33 without ATG (no-ATG group; median age 43, P < .0001) were compared.

RESULTS

Median time to engraftment was similar. Two-year cumulative incidence of moderate-to-severe chronic graft-versus-host disease (GVHD) was significantly lower in the ATG group (15% vs 55%, P < .0001), while that of acute GVHD was similar compared with the no-ATG group. After a median follow-up of 60 months (range, 14-184), the 3-year cumulative incidences of non-relapse mortality and relapse were 9% and 21% for ATG group and 15% and 19% for no-ATG group (P = .408 and P = .717), respectively, leading to a significantly better 3-year GVHD-free and relapse-free survival (GRFS) in the ATG group (55% vs 19%, P = .006): The 3-year overall and disease-free survival were similar. Infectious complication occurred with similar frequencies in both groups.

CONCLUSION

These findings suggest that ATG can be safely used to decrease moderate-to-severe chronic GVHD with improved GRFS for patients with MDS receiving MSD-HSCT in RIC setting.

Current Advances in Immunotherapy for Acute Leukemia: An Overview of Antibody, Chimeric Antigen Receptor, Immune Checkpoint, and Natural Killer

Recently, due to the application of hematopoietic stem cell transplantation and small molecule inhibitor, the survival of acute leukemia is prolonged. However, the 5 year survival rate remains low due to a high incidence of relapse. Immunotherapy is expected to improve the prognosis of patients with relapsed or refractory hematological malignancies because it does not rely on the cytotoxic mechanisms of conventional therapy. In this paper, the advances of immunotherapy in acute leukemia are reviewed from the aspects of Antibody including Unconjugated antibodies, Antibody-drug conjugate and Bispecific antibody, Chimeric Antigen Receptor (CARs), Immune checkpoint, Natural killer cells. The immunological features, mechanisms and limitation in clinic will be described.

Time-to-event analysis when the event is defined on a finite time interval

Acute graft-versus-host disease (GVHD) is a frequent complication following hematopoietic cell transplantation (HCT). Research on risk factors for acute GVHD has tended to ignore two important clinical issues. First, post-transplant mortality is high. In our motivating data, 100-day post-HCT mortality was 15.4%. Second, acute GVHD in its classic form is only diagnosed within 100 days of the transplant; beyond 100 days, a patient may be diagnosed with late onset acute or chronic GVHD. Standard modeling of time-to-event outcomes, however, generally conceive of patients being able to experience the event at any point on the time scale. In this paper, we propose a novel multi-state model that simultaneously: (i) accounts for mortality through joint modeling of acute GVHD and death, and (ii) explicitly acknowledges the finite time interval during which the event of interest can take place. The observed data likelihood is derived, with estimation and inference via maximum likelihood. Additionally, we provide methods for estimating the absolute risk of acute GVHD and death simultaneously. The proposed framework is compared via comprehensive simulations to a number of alternative approaches that each acknowledge some but not all aspects of acute GVHD, and illustrated with an analysis of HCT data that motivated this work.

Comparison of Two Doses of Antithymocyte Globulin in Reduced-Intensity Conditioning Allogeneic Hematopoietic Stem Cell Transplantation

The appropriate dose of antithymocyte globulin (ATG) to be used in reduced-intensity conditioning (RIC) allogeneic hematopoietic stem cell transplantation (allo-HSCT) is yet to be determined. We retrospectively analyzed the outcomes of patients who underwent unrelated or mismatch related RIC allo-HSCT for hematologic malignancies and received r-ATG (4.5 mg/kg, 141 patients) versus R-ATG (6 mg/kg, 216 patients). There was a higher incidence of cytomegalovirus (P < .001) and Epstein-Barr virus viremia (P =.03) in the R-ATG group than in the r-ATG group. The cumulative incidences of acute graft-versus-host disease (aGVHD) grades II to IV at day 180 in the r-ATG and R-ATG groups were 59% and 44% (P = .006) and grades III to IV 20% and 12% (P = .029), respectively. In multivariable models adjusting for disease diagnosis, the risk of aGVHD grades III to IV did not reach statistical significance (P = .087). The respective cumulative incidences of chronic GVHD in the r-ATG and R-ATG groups were 26% and 15% (P = .10), respectively. There were no significant differences in relapse rate (P = .24), nonrelapse mortality (P = .96), progression-free survival (P = .24), overall survival (P = .70), and GVHD-free relapse-free survival (P = .24). In this retrospective analysis, aGVHD incidence was higher in those treated with r-ATG compared with R-ATG, but this did not translate into significant differences of clinical outcome. Given the increasing use of RIC allo-HSCT for treating malignant hematologic conditions, the correct dose and schedule of ATG administration should be defined by prospective randomized controlled trials.

Cytomegalovirus infection is associated with AML relapse after allo-HSCT: a meta-analysis of observational studies

Cytomegalovirus (CMV) infection and primary disease relapse remain challenging problems after allogeneic hematopoietic stem cell transplantation (allo-HSCT). We sought to assess the association between CMV infection and disease relapse after transplantation. PubMed, EMBASE, the Cochrane Library, SCI, and Chinese Biomedicine Databases were searched up to July 1, 2018, for all studies that investigate pre-transplant CMV serostatus, CMV replication, and primary disease relapse in allo-HSCT patients with hematologic malignancies. Meta-analysis of 24 eligible cohort studies showed a significantly lower relapse risk after allo-HSCT in patients with CMV replication in acute myeloid leukemia (AML) (HR = 0.64, 95% CI, 0.50-0.83; P < 0.001) subgroup. However, CMV replication was associated with increased non-relapse mortality (NRM) in AML patients (HR = 1.64, 95% CI, 1.46-1.85; P < 0.001), but not associated with overall survival (OS) or graft-versus-host disease for AML patients (P > 0.05). There was no association between pre-transplant CMV serostatus and disease relapse, although D-/R- was associated with better OS in acute leukemia patients (HR = 0.89, 95% CI, 0.83-0.96; P = 0.003). In AML patients, CMV replication may be a protective predictor against disease relapse, although the potential benefit of CMV replication is offset by increased NRM.

Total body irradiation dose escalation decreases risk of progression and graft rejection after hematopoietic cell transplantation for myelodysplastic syndromes or myeloproliferative neoplasms

A non-myeloablative regimen of fludarabine and 200 cGy total body irradiation combined with post-grafting immunosuppression with mycophenolate mofetil and a calcineurin inhibitor facilitates allogeneic hematopoietic cell transplantation from HLA-matched related or unrelated donors in older patients and/or those with comorbidities. However, outcomes of prior studies have been disappointing in patients with myelodysplastic syndromes or myeloproliferative neoplasms due to high incidences of progression or graft failure (together termed hematopoietic cell transplantation-failure). We hypothesized that escalating the total body irradiation dose may improve the outcomes and subsequently performed a phase II total body irradiation dose-escalation trial. Patients with median age 66 years were enrolled in two arms to receive non-myeloablative conditioning followed by hematopoietic cell transplantation with total body irradiation dose escalation for excessive hematopoietic cell transplantation-failure: Arm A: myeloproliferative neoplasm/myelodysplastic syndrome low risk (n=36); and Arm B: myelodysplastic syndrome high-risk/chronic myelomonocytic leukemia (n=41). Total body irradiation dose levels were: Level-1 (300 cGy), Level-2 (400 cGy), or Level-3 (450 cGy). Patients received intravenous fludarabine 30 mg/m² for three days. Total body irradiation was administered on day 0 followed by infusion of peripheral blood stem cells from HLA-matched related (n=30) or unrelated (n=47) donors. Post-grafting immunosuppression with mycophenolate mofetil and cyclosporine was administered. The primary end point was day 200 hematopoietic cell transplant failure, with the objective of reducing the incidence to <20%. The primary end point was reached on Arm A at dose Level-1 (300 cGy total body irradiation) with a cumulative incidence of day 200 hematopoietic cell transplant failure of 11%, and on Arm B at dose Level-3 (450 cGy) with a cumulative incidence of day 200 hematopoietic cell transplant failure of 9%. Increasing the total body irradiation dose leads to a higher success rate with non-myeloablative conditioning by reducing relapse and rejection. Further studies are necessary to decrease non-relapse mortality, especially among patients with high-risk disease. Trial registered under clinicaltrials.gov identifier: NCT00397813.

Implantable pre-metastatic niches for the study of the microenvironmental regulation of disseminated human tumour cells

Cancer survivors often carry disseminated tumour cells (DTCs), yet owing to DTC dormancy they do not relapse from treatment. Understanding how the local microenvironment regulates the transition of DTCs from a quiescent state to active proliferation could suggest new therapeutic strategies to prevent or delay the formation of metastases. Here, we show that implantable biomaterial microenvironments incorporating human stromal cells, immune cells and cancer cells can be used to examine the post-dissemination phase of the evolution of the tumour microenvironment. After subdermal implantation in mice, porous hydrogel scaffolds seeded with human bone marrow stromal cells form a vascularized niche and recruit human circulating tumour cells released from an orthotopic prostate tumour xenograft. Systemic injection of human peripheral blood mononuclear cells slowed the evolution of the active metastatic niches but did not change the rate of overt metastases, as the ensuing inflammation promoted the formation of DTC colonies. Implantable pre-metastatic niches might enable the study of DTC colonization and proliferation, and facilitate the development of effective anti-metastatic therapies.

Single- Versus Double-Unit Umbilical Cord Blood Transplantation for Hematologic Diseases: A Systematic Review

Controversial results exist regarding the clinical benefits of single- vs double-unit umbilical cord blood transplantation (UCBT) in patients with hematologic diseases. A systematic review was conducted to evaluate this issue. The PubMed, Embase, and Cochrane Library databases were searched up to May 2018. A total of 25 studies including 6571 recipients were identified. Although double-unit UCB contained higher doses of total nucleated cells and CD34⁺ cells, it offered no advantages over single-unit UCB in terms of hematologic recovery, including the rate and speed of neutrophil and platelet engraftment. Double-unit UCBT was associated with higher incidences of grades II-IV acute and extensive chronic graft-vs-host disease, accompanied by a lower relapse incidence, which may be attributed to a graft-vs-graft effect induced by double-unit UCB. However, transplant-related mortality, disease-free survival, and overall survival were comparable between single- and double-unit UCBT. Although double-unit UCBT confers no clinical advantages over single-unit UCBT, certain patients, such as those at high risk of relapse, might benefit from double-unit UCBT, a possibility that needs to be clarified in future randomized trials.

Long-Term Follow-Up of 90Y-Ibritumomab Tiuxetan, Fludarabine, and Total Body Irradiation-Based Nonmyeloablative Allogeneic Transplant Conditioning for Persistent High-Risk B Cell Lymphoma

Nonmyeloablative allogeneic hematopoietic cell transplantation (HCT) can provide prolonged remissions in patients with advanced B cell lymphoma (B-NHL) via the graft-versus-lymphoma effect, although inferior results are seen in patients with chemoresistant, bulky, or aggressive disease. Radioimmunotherapy can safely induce responses in B-NHL with minimal nonhematologic toxicity. Initial results of 90Y-ibritumomab tiuxetan-based allografting demonstrated early safety and disease control in nonremission patients but with short follow-up. Here we report the long-term outcomes of patients treated on this study with specific emphasis on patients achieving early remissions. Eleven of 40 patients were alive at a median follow-up of 9 years (range, 5.3 to 10.2). Fourteen (35%) deaths were due to disease progression and 14 (35%) deaths to complications from HCT. One patient died of a Merkel cell carcinoma. The 5-year overall and progression-free survival for patients with indolent B-NHL was 40% and 27.5%, respectively. None of the patients with diffuse large B cell lymphoma was a long-term disease-free survivor regardless of early remission status. 90Y-ibritumomab tiuxetan-based allografting represents a viable option in patients with indolent histologies. Improved strategies are needed for aggressive B-NHL. The original trial was registered at www.clinicaltrials.gov as NCT00119392.

Xenogeneic Graft-Versus-Host Disease in Humanized NSG and NSG-HLA-A2/HHD Mice

Despite the increasing use of humanized mouse models to study new approaches of graft-versus-host disease (GVHD) prevention, the pathogenesis of xenogeneic GVHD (xGVHD) in these models remains misunderstood. The aim of this study is to describe this pathogenesis in NOD/LtSz-Prkdc^scidIL2rγ^tm1Wjl (NSG) mice infused with human PBMCs and to assess the impact of the expression of HLA-A0201 by NSG mice cells (NSG-HLA-A2/HHD mice) on xGVHD and graft-versus-leukemia (GvL) effects, by taking advantage of next-generation technologies. We found that T cells recovered from NSG mice after transplantation had upregulated expression of genes involved in cell proliferation, as well as in TCR, co-stimulatory, IL-2/STAT5, mTOR and Aurora kinase A pathways. T cells had mainly an effector memory or an effector phenotype and exhibited a Th1/Tc1-skewed differentiation. TCRβ repertoire diversity was markedly lower both in the spleen and lungs (a xGVHD target organ) than at infusion. There was no correlation between the frequencies of specific clonotypes at baseline and in transplanted mice. Finally, expression of HLA-A0201 by NSG mice led to more severe xGVHD and enhanced GvL effects toward HLA-A2⁺ leukemic cells. Altogether our data demonstrate that the pathogenesis of xGVHD shares important features with human GVHD and that NSG-HLA-A2/HHD mice could serve as better model to study GVHD and GvL effects.

[Treatment of 30 elderly patients with advanced myeloid neoplasm by allogeneic hematopoietic stem cell transplantation]

Objective: To evaluate the efficacy of allogeneic hematopoietic stem cell transplantation (allo-HSCT) for elderly patients with advanced myeloid neoplasm. Methods: From September 2014 to September 2017, 30 consecutive hospitalized 50-plus-year-old myeloid neoplasm patients were retrospectively analyzed. At the time of transplantation, 6 patients reached complete remission and the others remained no remission after treatment. The donors were identical sibling (12), matched unrelated (6) and haploidentical family member (12), respectively. 18 patients received RIC while 12 patients received MAC conditioning regiments consisted of Busulfan, cytarabine, fludarabine or clarithromycin±TBI, respectively. Results: Five patients died early in the conditioning stage, 24 patients successfully engrafted. The median time of neutrophil engraftment was 14(10-18) d, whereas platelet engraftment was 15(10-19) d. Six cases (25%) experienced aGVHD grades Ⅱ, 8 cases (32%) cGVHD, including moderate to severe cGVHD in 2 cases (8%). Seven, 7 and 5 cases developed CMV viremia, pneumonia and herpeszoster, respectively after transplantation, but no patients died of infections. The median follow-up time of the patients was 7(0.5-38) months. Twenty-one patients were still alive. The estimated 2 years OS and LFS were 62.5% (95% CI 39.2%-85.8%) and 59.2% (95% CI 26.9%-91.5%), respectively. Univariate analysis showed that HCT-CI was the only factor influencing OS. Conclusion: Allogeneic hematopoietic stem cell transplantation could improve the survival of elderly patients with myeloid neoplasm.

Variability of contribution of vitamin D receptor gene polymorphisms to outcome of HLA-matched sibling allogeneic bone marrow transplantation

Graft-versus-host disease (GVHD) remains one of the major complications of hematopoietic stem cell transplantation (HSCT). Several etiological factors were investigated. Among these, vitamin D and hence its receptor (VDR) gene polymorphisms have gained much interest; however, the results are still controversial. Using PCR-RFLP, we genotyped VDR polymorphisms FokI (rs10735810), ApaI (rs7975232), and Taq1 (rs731236) in 80 patient/donor pairs according to DNA availability. No association was encountered between VDR polymorphisms and GVHD. Neither was there any impact on survival. Only grade II-IV acute GVHD was associated with inferior overall (p = .01), but not disease-free survival. The controversy between our results and the literature may be attributed to marked variability in the relative distribution of VDR genotypes in different populations. Also different environmental factors, including exposure to sun, may ensure vitamin D sufficiency nullifying the impact of VDR polymorphisms.

Umbilical Cord Blood Transplantation Corrects Very Early-Onset Inflammatory Bowel Disease in Chinese Patients With IL10RA-Associated Immune Deficiency

BACKGROUND

Hematopoietic stem cell transplantation is considered the only curative therapy for very early-onset inflammatory bowel disease with specific immune defects, such as interleukin-10 receptor deficiency. We performed reduced-intensity conditioning before umbilical cord blood transplantation in patients with interleukin-10 receptor-A deficiency.

METHODS

We enrolled 9 very early-onset inflammatory bowel disease patients with typical manifestations. We diagnosed the patients with interleukin-10 receptor-A deficiency by whole-exome sequencing. Umbilical cord blood transplantation was performed in all 9 patients. Eight patients received the reduced-intensity conditioning regimen, and 1 patient received the myeloablative conditioning regimen.

RESULTS

All 9 patients received transplantation between the ages of 6 months to 43 months (average, 16.8 months) with body weights ranging from 3 to 10.4 kg (average, 6.6 kg). The patients displayed complete chimerism at 2-8 weeks after transplantation; 6 patients achieved complete remission without evidence of graft-vs-host disease or infections; 1 patient died of chronic lung graft-vs-host disease at 6 months post-transplantation; and the other 2 patients died of sepsis post-transplantation because of unsuccessful engraftments. Severe malnutrition and growth retardation associated with interleukin-10 receptor-A deficiency were significantly improved post-transplantation.

CONCLUSIONS

We recommend umbilical cord blood transplantation as a potential treatment for very early-onset inflammatory bowel disease with a defined monogenic immunodeficiency, and we suggest that reduced-intensity conditioning chemotherapy is more suitable than myeloablative conditioning for patients with severe malnutrition and bowel disease. We have demonstrated success with reduced-intensity conditioning for interleukin-10 receptor-A deficiency in pediatric patients with severe clinical conditions. 10.1093/ibd/izy028_video1izy028.video15786489183001.

Genetically enhanced T lymphocytes and the intensive care unit

Chimeric antigen receptor-modified T cells (CAR-T cells) and donor lymphocyte infusion (DLI) are important protocols in lymphocyte engineering. CAR-T cells have emerged as a new modality for cancer immunotherapy due to their potential efficacy against hematological malignancies. These genetically modified receptors contain an antigen-binding moiety, a hinge region, a transmembrane domain, and an intracellular costimulatory domain resulting in lymphocyte T cell activation subsequent to antigen binding. In present-day medicine, four generations of CAR-T cells are described depending on the intracellular signaling domain number of T cell receptors. DLI represents a form of adoptive therapy used after hematopoietic stem cell transplant for its anti-tumor and anti-infectious properties. This article covers the current status of CAR-T cells and DLI research in the intensive care unit (ICU) patient, including the efficacy, toxicity, side effects and treatment.

Impact of Donor Type in Patients with AML Given Allogeneic Hematopoietic Cell Transplantation After Low-Dose TBI-Based Regimen

Purpose: We assessed the impact of donor type in acute myeloid leukemia (AML) patients transplanted with 2 Gy total body irradiation (TBI)-based nonmyeloablative conditioning regimen.Patients and Methods: Data from 1,715 adult patients, with AML in CR1 or CR2 were included in this retrospective survey.Results: Donors consisted either of HLA-matched sibling donors (MSD, n = 701), 10/10 HLA-matched unrelated donors (MUD, n = 611), HLA-haploidentical donors (haplo, n = 112) or single or double umbilical cord bloods (CBT, n = 291). Chronic graft-versus-host disease (GVHD) was less frequent in CBT (28%) and in haplo (30%) patients than in MSD (50%) and MUD (51%) recipients (P < 0.001). Two-year incidence of relapse was 32%, 30%, 34%, and 34% in MSD, MUD, CBT and haplo patients, respectively (P = 0.7). Two-year overall (OS) and GVHD-free relapse-free survival (GRFS) were 59% and 29% in MSD patients, 56% and 39% in CBT recipients, 53% and 23% in MUD recipients, and 43% and 37% in haplo patients, respectively. In multivariate analyses, MUD patients had lower GRFS than MSD patients beyond day 100 (HR 1.3, P = 0.001) while CBT was associated with a better GRFS than MSD beyond day 100 (HR 0.6, P = 0.002).Conclusions: In this large cohort of AML patients transplanted following low-dose TBI-based conditioning, the relapse incidence was not affected by donor type suggesting that the intensity of GVL effects might be comparable with these four transplant approaches. Furthermore, CBT was associated with better GRFS beyond day 100 than MSD while the opposite was observed for MUD. Clin Cancer Res; 24(12); 2794-803. ©2018 AACR.

Occurrence of graft-versus-host disease increases mortality after umbilical cord blood transplantation for acute myeloid leukaemia: a report from Eurocord and the ALWP of the EBMT

BACKGROUND

The efficacy of umbilical cord blood transplantation (UCBT) as treatment for acute myeloid leukaemia (AML) relies on immune-mediated graft-versus-leukaemia effects. Previous studies have suggested a strong association between graft-versus-host disease (GVHD) occurrence and graft-versus-leukaemia effects after allogeneic hematopoietic cell transplantation.

METHODS

Here, we evaluated the kinetics of relapse rate in correlation with GVHD occurrence after UCBT. The kinetics of relapse rate over time in correlation to GVHD occurrence were assessed by calculating the relapse rate per patient-year within sequential 90-day intervals. The impact of GVHD on relapse and mortality was further studied in multivariate Cox models handling GVHD as a time-dependent covariate.

RESULTS

The study included data from 1068 patients given single (n = 567) or double (n = 501) UCBT. The proportion of patients with grade II, III and IV acute GVHD was 20%, 7% and 4%, respectively. At 2 years, the cumulative incidence of chronic GVHD was 42%, the cumulative incidence of relapse was 32%, and overall survival was 32% as well. Relapse rates declined gradually over time during the first 30 months after transplantation. There was a possible suggestion that grade II-IV acute (HR = 0.8, P = 0.1) and chronic (HR = 0.65, P = 0.1) GVHD decreased relapse risk. However, grade II-IV acute GVHD significantly increased early (the first 18 months after UCBT) mortality (HR = 1.3, P = 0.02), whilst chronic GVHD increased each early (HR = 2.7, P < 0.001) and late (HR = 4.9, P < 0.001) mortality after UCBT.

CONCLUSIONS

The occurrence of grade II-IV acute or chronic GVHD each increases overall mortality after UCBT for AML mitigating the possible graft-versus-leukemia effect of GVHD.

HLA-DPB1 mismatch induces a graft-versus-leukemia effect without severe acute GVHD after single-unit umbilical cord blood transplantation

Although it is known that human leukocyte antigen (HLA)-DPB1 disparity has a strong impact on outcomes in unrelated hematopoietic transplantation with induction of acute graft-versus-host disease (GVHD) and a graft-versus-leukemia (GVL) effect, its role in unrelated umbilical cord blood transplantation (UR-CBT) has yet to be fully clarified. Our current study is being conducted to elucidate the impact of HLA-DPB1 mismatch, along with the effect of other HLA loci mismatches at the allele level. HLA six loci alleles were retrospectively typed in 1157 Japanese donors and patients with leukemia or myelodysplastic syndrome who underwent transplantation with a single unit of cord blood. HLA-DPB1 mismatch was associated with a significant reduction in leukemia relapse (hazard ratio 0.61, P<0.001), whereas the other HLA loci allele-level mismatches did not. No significant effect of HLA-DPB1 mismatch was observed in the risk of acute GVHD, engraftment or mortality. This HLA-DPB1 GVL effect without induction of severe acute GVHD or deterioration of survival rate has not been reported in unrelated bone marrow or peripheral blood stem cell transplantations, suggesting apparent advantages of UR-CBT. Accordingly, selection of an HLA-DPB1 mismatch cord blood might be the preferable choice for single-unit UR-CBT.

Azacytidine prevents experimental xenogeneic graft-versus-host disease without abrogating graft-versus-leukemia effects

The demethylating agent 5-azacytidine (AZA) has proven its efficacy in the treatment of myelodysplastic syndrome and acute myeloid leukemia. In addition, AZA can demethylate FOXP3 intron 1 (FOXP3i1) leading to the generation of regulatory T cells (Treg). Here, we investigated the impact of AZA on xenogeneic graft-vs.-host disease (xGVHD) and graft-vs.-leukemia effects in a humanized murine model of transplantation (human PBMCs-infused NSG mice), and described the impact of the drug on human T cells in vivo. We observed that AZA improved both survival and xGVHD scores. Further, AZA significantly decreased human T-cell proliferation as well as IFNγ and TNF-α serum levels, and reduced the expression of GRANZYME B and PERFORIN 1 by cytotoxic T cells. In addition, AZA significantly increased Treg frequency through hypomethylation of FOXP3i1 as well as increased Treg proliferation. The latter was subsequent to higher STAT5 signaling in Treg from AZA-treated mice, which resulted from higher IL-2 secretion by conventional T cells from AZA-treated mice itself secondary to demethylation of the IL-2 gene promoter by AZA. Importantly, Tregs harvested from AZA-treated mice were suppressive and stable over time since they persisted at high frequency in secondary transplant experiments. Finally, graft-vs.-leukemia effects (assessed by growth inhibition of THP-1 cells, transfected to express the luciferase gene) were not abrogated by AZA. In summary, our data demonstrate that AZA prevents xGVHD without abrogating graft-vs.-leukemia effects. These findings could serve as basis for further studies of GVHD prevention by AZA in acute myeloid leukemia patients offered an allogeneic transplantation.

Low incidence of acute graft-versus-host disease with short-term tacrolimus in haploidentical hematopoietic stem cell transplantation

Although tacrolimus (Tac) has immunosuppressive properties and exhibits promising efficacy against graft-versus-host disease (GVHD), little is known about Tac in the prophylaxis of GVHD after HLA-haploidentical hematopoietic stem cell transplantation (haplo-HSCT). In a multicenter randomized controlled trial, 174 patients received haplo-HSCT with GVHD prophylaxis involving short-term Tac (from -8days to +30days) or cyclosporine (CsA). The 100day cumulative incidences of acute GVHD (aGVHD) and grade III-IV aGVHD with the short-term Tac regimen and CsA regimen were 29.1 (19.5-38.7)% vs. 50.0(39.6-60.4)% (p=0.005) and 3.6(0.0-7.5)% vs. 13.5(6.1-20.9)% (p=0.027), respectively. There were no significant differences in the incidences of chronic GVHD (cGVHD), relapse and cytomegalovirus infection. Lymphocyte subset analysis showed that T cells decreased to lower levels on the short-term Tac regimen within 3 months of transplantation. The disease-free survival and overall survival on the short-term Tac and CsA regimens were 59.3 (48.9-69.7)% vs. 55.7 (45.3-66.1)% (p=0.696) and 65.1 (55.1-75.1)% vs. 61.4 (51.2-71.6)% (p=0.075), respectively. Our findings indicate that the short-term Tac regimen for GVHD prophylaxis in patients undergoing haplo-HSCT is associated with a low incidence and slight severity of aGVHD and did not increase the incidence of relapse and cytomegalovirus infection.

Myeloablative Versus Reduced-Intensity Hematopoietic Cell Transplantation for Acute Myeloid Leukemia and Myelodysplastic Syndromes

Purpose The optimal regimen intensity before allogeneic hematopoietic cell transplantation (HCT) is unknown. We hypothesized that lower treatment-related mortality (TRM) with reduced-intensity conditioning (RIC) would result in improved overall survival (OS) compared with myeloablative conditioning (MAC). To test this hypothesis, we performed a phase III randomized trial comparing MAC with RIC in patients with acute myeloid leukemia or myelodysplastic syndromes. Patients and Methods Patients age 18 to 65 years with HCT comorbidity index ≤ 4 and < 5% marrow myeloblasts pre-HCT were randomly assigned to receive MAC (n = 135) or RIC (n = 137) followed by HCT from HLA-matched related or unrelated donors. The primary end point was OS 18 months post-random assignment based on an intent-to-treat analysis. Secondary end points included relapse-free survival (RFS) and TRM. Results Planned enrollment was 356 patients; accrual ceased at 272 because of high relapse incidence with RIC versus MAC (48.3%; 95% CI, 39.6% to 56.4% and 13.5%; 95% CI, 8.3% to 19.8%, respectively; P < .001). At 18 months, OS for patients in the RIC arm was 67.7% (95% CI, 59.1% to 74.9%) versus 77.5% (95% CI, 69.4% to 83.7%) for those in the MAC arm (difference, 9.8%; 95% CI, -0.8% to 20.3%; P = .07). TRM with RIC was 4.4% (95% CI, 1.8% to 8.9%) versus 15.8% (95% CI, 10.2% to 22.5%) with MAC ( P = .002). RFS with RIC was 47.3% (95% CI, 38.7% to 55.4%) versus 67.8% (95% CI, 59.1% to 75%) with MAC ( P < .01). Conclusion OS was higher with MAC, but this was not statistically significant. RIC resulted in lower TRM but higher relapse rates compared with MAC, with a statistically significant advantage in RFS with MAC. These data support the use of MAC as the standard of care for fit patients with acute myeloid leukemia or myelodysplastic syndromes.

A Review of Myeloablative vs Reduced Intensity/Non-Myeloablative Regimens in Allogeneic Hematopoietic Stem Cell Transplantations

Allogeneic hematopoietic stem cell transplantation (Allo-HSCT) is a curative treatment option for both malignant and some benign hematological diseases. During the last decade, many of the newer high-dose regimens in different intensity have been developed specifically for patients with hematologic malignancies and solid tumors. Today there are three main approaches used prior to allogeneic transplantation: Myeloablative (MA), Reduced Intensity Conditioning (RIC) and Non-MA (NMA) regimens. MA regimens cause irreversible cytopenia and there is a requirement for stem cell support. Patients who receive NMA regimen have minimal cytopenia and this type of regimen can be given without stem cell support. RIC regimens do not fit the criteria of MA and NMA: the cytopenia is reversible and the stem cell support is necessary. NMA/RIC for Allo-HSCT has opened a new era for treating elderly patients and those with comorbidities. The RIC conditioning was used for 40% of all Allo-HSCT and this trend continue to increase. In this paper, we will review these regimens in the setting of especially allogeneic HSCT and our aim is to describe the history, features and impact of these conditioning regimens on specific diseases.