High CD4/CD8 ratio in allografts predicts adverse outcomes in unmanipulated HLA-mismatched/haploidentical hematopoietic stem cell transplantation for chronic myeloid leukemia

Low Immunogenicity of Keratinocytes Derived from Human Embryonic Stem Cells

Epidermal transplantation is a common and widely used surgical technique in clinical medicine. Derivatives of embryonic stem cells have the potential to serve as a source of transplantable cells. However, allograft rejection is one of the main challenges. To investigate the immunogenicity of keratinocytes derived from human embryonic stem cells (ESKCs), we conducted a series of in vivo and in vitro experiments. The results showed that ESKCs have low HLA molecule expression, limited antigen presentation capabilities, and a weak ability to stimulate the proliferation and secretion of inflammatory factors in allogeneic PBMCs in vitro. In humanized immune mouse models, ESKCs elicited weak transplant rejection responses in the host. Overall, we found that ESKCs have low immunogenicity and may have potential applications in the field of regenerative medicine.

T-cell dysfunctions in myelodysplastic syndromes

ABSTRACT

Escape from immune surveillance is a hallmark of cancer. Immune deregulation caused by intrinsic and extrinsic cellular factors, such as altered T-cell functions, leads to immune exhaustion, loss of immune surveillance, and clonal proliferation of tumoral cells. The T-cell immune system contributes to the pathogenesis, maintenance, and progression of myelodysplastic syndrome (MDS). Here, we comprehensively reviewed our current biological knowledge of the T-cell compartment in MDS and recent advances in the development of immunotherapeutic strategies, such as immune checkpoint inhibitors and T-cell- and antibody-based adoptive therapies that hold promise to improve the outcome of patients with MDS.

Graft CD8 T-cell-based risk system predicts survival in antithymocyte globulin-based myeloablative haploidentical peripheral blood stem cell transplantation

Objective

This study investigated the cellular composition of peripheral blood grafts for anti-thymocyte globulin (ATG)-based myeloablative haploidentical haematopoietic stem cell transplantation (haplo-HSCT).

Methods

Clinical characteristics were retrospectively evaluated in a training cohort with ATG-based myeloablative haplo-HSCT between January 2016 and February 2020 and confirmed in a validation cohort between March 2020 and June 2021.

Results

A higher dose of graft CD8+ T cells (≥ 0.85 × 108 kg-1) was significantly improved overall survival (OS; hazard ratio [HR], 1.750; P = 0.002) and disease-free survival (DFS; HR, 1.751; P < 0.001) in the training cohort, according to multivariate Cox regression analysis. Higher doses of mononuclear cells (MNCs) demonstrated better OS (HR, 1.517; P = 0.038) and DFS (HR, 1.532; P = 0.027). Older patient age (> 46 years), older donor age (≥ 50 years) and a higher refined disease risk index (rDRI) were also related to OS. A graft CD8+ T-cell risk system based on graft CD8+ T-cell dose, donor age and rDRI was constructed using a nomogram model after LASSO Cox regression analysis. It showed acceptable discrimination, with a C-index of 0.62 and 0.63, respectively. Graft CD8+ T-cell dose was negatively correlated with donor age (P < 0.001) and positively correlated with a higher lymphocyte percentage in the peripheral blood before mobilisation (P < 0.001).

Conclusion

A higher CD8+ T-cell dose in peripheral blood-derived grafts improves patients' survival with ATG-based myeloablative haplo-HSCT. Younger donors with higher lymphocyte percentages improved patients' survival with an intermediate rDRI risk.

The importance of graft cell composition in outcome after allogeneic stem cell transplantation in patients with malignant disease

BACKGROUND

Graft-versus-host disease (GVHD) and relapse remain majobstacles ftreatment success in allogeneic hematopoietic stem cell transplantation (HSCT). In the present study, we evaluated the immune cell profile of the graft to outcome after HSCT.

STUDY DESIGN AND METHOD

Flow cytometry data of graft cell subsets [CD34⁺ , CD3⁺ , CD19⁺ , CD4⁺ , CD8⁺ , CD3-CD56⁺ CD16⁺ , CD4⁺ CD127^low CD25^high ] from G-CSF primed peripheral blood stem cell (PBSC) donors was collected retrospectively from 299 patients with hematological malignancies undergoing HSCT between 2006 and 2013. The association to overall survival, transplant-related mortality (TRM), GVHD and probability of relapse was analyzed. Patients outcome from HLA-identical sibling (Sib) (n = 97) and unrelated donors (URD) (n = 202) were analyzed separately as all URD patients received anti-thymocyte globulin (ATG).

RESULTS

Five-year overall survival was similar in the two cohorts (68% (Sib) vs 65% (URD)). The relapse incidence was significantly lower in the Sib cohort (24% vs 35%, P = 0.04). Multivariate analysis in the URD group revealed an association between a higher CD8⁺ dose and less relapse (HR, 0.94; 95%CI, 0.90-0.98; P = 0.006) as well as an association between higher CD34⁺ dose and both higher TRM (HR, 1.09; 95%CI, 1.02-1.20; P = 0.02) and relapse (HR, 1.09; 95%CI, 1.01-1.17; P = 0.025). The Sib analysis showed an association between a higher graft CD19⁺ dose and more severe acute GVHD (HR, 1,09; 95%CI, 1.03-1.15; P = 0.003) and TRM (HR, 1.09; 95%CI, 1.01-1.17; P = 0.036). In addition, a higher CD4⁺ graft content was associated to an increased risk for chronic GVHD (HR, 1.02; 95%CI 1.00-1.04; P = 0.06).

CONCLUSION

These data indicate an importance of PBSC dongraft composition in patients with a hematological malignancy.

Relationship of Cell Compositions in Allografts with Outcomes after Haploidentical Transplantation for Acquired Severe Aplastic Anemia: Effects of CD34+ and CD14+ Cell Doses

Background

The dose of certain cell types in allografts affects engraftment kinetics and clinical outcomes after allogeneic stem cell transplantation (SCT). Hence, the present study investigated the association of cell compositions in allografts with outcomes after unmanipulated haploidentical SCT (haplo-SCT) for patients with acquired severe aplastic anemia (SAA).

Methods

A total of 131 patients with SAA who underwent haplo-SCT were retrospectively enrolled. Cell subsets in allografts were determined using flow cytometry. To analyze the association of cellular compositions and outcomes, Mann-Whitney U nonparametric tests were conducted for patient age, sex, weight, human leukocyte antigen mismatched loci, ABO-matched status, patient ABO blood type, donor-recipient sex match, donor-recipient relationship, and each graft component. Multivariate analysis was performed using logistic regression to determine independent influence factors involving dichotomous variables selected from the univariate analysis.

Results

A total of 126 patients (97.7%) achieved neutrophil engraftment, and 121 patients (95.7%) achieved platelet engraftment. At 100 days after transplantation, the cumulative incidence of II-IV acute graft-versus-host disease (GVHD) was 32.6%. After a median follow-up of 842 (range: 124-4110) days for surviving patients, the cumulative incidence of total chronic GVHD at 3 years after transplantation was 33.7%. The probability of overall survival at 3 years was 83.0%. Multivariate analysis showed that higher total doses of CD14⁺ (P = 0.018) and CD34⁺ cells (P < 0.001) were associated with a successful platelet engraftment. A successful platelet was associated with superior survival (P < 0.001). No correlation of other cell components with outcomes was observed.

Conclusions

These results provide evidence and explain that higher doses of CD34⁺ and CD14⁺ cells in haploidentical allografts positively affect platelet engraftment, contributing to superior survival for patients with SAA.

Aerobic exercise in humans mobilizes HSCs in an intensity-dependent manner

Hematopoietic stem and progenitor cells are necessary to maintain, repair, and reconstitute the hematopoietic blood cell system. Mobilization of these cells from bone marrow to blood can be greatly increased under certain conditions, one such being exercise. The purpose of this study was to identify the importance of exercise intensity in hematopoietic mobilization, to better understand the mobilization kinetics postexercise, and to determine if exercise is capable of mobilizing several specific populations of hematopoietic cells that have clinical relevance in a transplant setting. Healthy individuals were exercised on a cycle ergometer at 70% of their peak work rate (WRpeak) until volitional fatigue and at 30% of their WRpeak work matched to the 70% WRpeak bout. Blood was collected before, immediately post, and 10, 30, and 60 min postexercise. Total blood cells, hematocrit, and mononuclear cells isolated by density gradient centrifugation were counted. Specific populations of hematopoietic stem cells were analyzed by flow cytometry. Mononuclear cells, CD34+, CD34+/CD38-, CD34+/CD110+, CD3-/CD16+/CD56+, CD11c+/CD123-, and CD11c-/CD123+ cells per millilter of blood increased postexercise. Overall, the 70% WRpeak exercise group showed greater mobilization immediately postexercise, while there was no observable increase in mobilization in the work matched 30% WRpeak exercise group. Mobilization of specific populations of hematopoietic cells mirrored changes in the general mobilization of mononuclear cells, suggesting that exercise serves as a nonspecific mobilization stimulus. Evidently, higher intensity exercise is capable of mobilizing hematopoietic cells to a large extent and immediately postexercise is an ideal time point for their collection.

NEW & NOTEWORTHY

Here we demonstrate for the first time that mobilization of hematopoietic stem cells (HSCs) through exercise is intensity dependent, with the greatest mobilization occurring immediately after high-intensity exercise. As well, we show that exercise is a general stimulus for mobilization: increases in specific HSC populations are reliant on general mononuclear cell mobilization. Finally, we demonstrate no differences in mobilization between groups with different aerobic fitness.

Selective Migration of Subpopulations of Bone Marrow Cells along an SDF-1α and ATP Gradient

Both stem cell chemokine stromal cell-derived factor-1α (SDF-1α) and extracellular nucleotides such as adenosine triphosphate (ATP) are increased in ischemic myocardium. Since ATP has been reported to influence cell migration, we analysed the migratory response of bone marrow cells towards a combination of SDF-1 and ATP. Total nucleated cells (BM-TNCs) were isolated from bone marrow of cardiac surgery patients. Migration assays were performed in vitro. Subsequently, migrated cells were subjected to multicolor flow cytometric analysis of CD133, CD34, CD117, CD184, CD309, and CD14 expression. BM-TNCs migrated significantly towards a combination of SDF-1 and ATP. The proportions of CD34+ cells as well as subpopulations coexpressing multiple stem cell markers were selectively enhanced after migration towards SDF-1 or SDF-1 + ATP. After spontaneous migration, significantly fewer stem cells and CD184+ cells were detected. Direct incubation with SDF-1 led to a reduction of CD184+ but not stem cell marker-positive cells, while incubation with ATP significantly increased CD14+ percentage. In summary, we found that while a combination of SDF-1 and ATP elicited strong migration of BM-TNCs in vitro, only SDF-1 was responsible for selective attraction of hematopoietic stem cells. Meanwhile, spontaneous migration of stem cells was lower compared to BM-TNCs or monocytes.

The cell composition of infused donor lymphocyte has different impact in different types of allogeneic hematopoietic stem cell transplantation

Donor lymphocyte infusion (DLI) is often used to enhance the graft-versus-leukemia (GVL) effect after allogeneic hematopoietic stem cell transplantation (allo-HSCT). In this study, we first evaluated the impact of the cell composition of a modified DLI (mDLI) on the prognoses of patients. A total of 194 patients undergoing allo-HSCT were enrolled and received mDLI for various clinical reasons. The infused cellular components of the mDLI were examined by flow cytometry. The results showed that infusion with a lower dose of CD14(+) cells (<0.33 × 10(8) /kg) was an independent risk factor for the occurrence of II-IV acute graft-versus-host disease (aGVHD) (HR = 0.104, p = 0.032) in human leukoctye antigen-identical transplant patients. In addition, a dose of CD14(+) cells greater than the 50th percentile was associated with a lower incidence of hematological relapse and longer disease-free survival (DFS) after the mDLI (relapse: HR = 0.193, p = 0.007; DFS: HR = 0.259, p = 0.016). However, we also found that a greater number of CD14(+) cells were an independent risk factor for II-IV aGVHD (HR = 1.758, p = 0.034) in haploidentical allo-HSCT. In conclusion, our data were the first to demonstrate that the cell composition of a 56 mDLI played a distinct role in different types of allo-HSCT. This finding provided a novel approach for the development of cellular therapies by manipulating the components of infused cells.

Haploidentical hematopoietic stem cell transplantation in hematologic malignancies with G-CSF mobilized bone marrow plus peripheral blood stem cells grafts without T cell depletion: a single center report of 29 cases

Haploidentical Hematopoietic stem cell transplantation (Haplo-HSCT) has provided an alternative option since virtually all patients have an immediately available donor. Here, we report the results of Haplo-HSCT with granulocyte-colony-stimulating factor (G-CSF) mobilized bone marrow grafts plus peripheral blood stem cells as the grafts without T-cell depletion. Twenty-nine patients with the mean age of 27.27 years (ranging from 15 to 51 years) were enrolled in this study, and 10 cases were in high risk status. The patients received myeloablative preconditioning with or without total body irradiation and acute graft-versus-host disease (GVHD) prophylaxis consisting of basiliximab, cyclosporine A, methotrexate, mycophenolate mofetil and a rabbit anti-thymocyte globulin. All the patients attained successful neutrophil and platelet recovery. The mean times for neutrophil and platelet recovery were 17.1 and 20.9 days, respectively. During the follow-up at a median time of 30.69 months (ranging from 3 to 76 months), nine patients developed aGVHD grade II-IV, including two developed grade III-IV GVHD after donor lymphocyte infusion. The incidence of cGVHD was 48.3%. 13 patients died within the first two years after transplantation, and the total disease-free survival rate longer than 2 years was 55.2%. These results suggest that G-CSF-primed bone marrow plus peripheral blood stem cell grafts are an appropriate stem cell source for Haplo-HSCT and large scale investigations are needed to confirm this protocol.

The impact of graft composition on clinical outcomes in pediatric patients undergoing unmanipulated HLA-mismatched/haploidentical hematopoietic stem cell transplantation

OBJECTIVE

In pediatric patients, the association of graft composition with clinical outcomes after unmanipulated haploidentical hematopoietic stem cell transplantation has not been well defined. Therefore, the impact of graft composition on transplant outcomes was evaluated.

METHODS

We examined the absolute numbers and relative proportions of CD3+, CD4+, CD8+, CD14+, and CD34+ cells contained in allografts of 103 children who underwent unmanipulated HLA-mismatched/haploidentical hematopoietic stem cell transplantation (HSCT) without in vitro T cell depletion.

RESULTS

Multivariate analysis showed that a high CD34+ cell dose in G-CSF-primed bone marrow and peripheral blood grafts (G-PB) was related to accelerated platelet engraftment (P = 0.004). A higher CD3/CD14 ratio in G-PB (≥ 1.30) was associated with grade II-IV acute graft-versus-host disease (GVHD) (HR = 3.552; 95%CI 1.015-12.428, P = 0.047). In addition, only a heavier donor weight (HR = 5.837; 95%CI 1.841-18.513, P = 0.003) and a higher ratio of CD3/CD14 in the total graft (HR = 9.752; 95%CI 1.834-51.865, P = 0.008) were associated with worse overall survival. No aspect of graft composition affected neutrophil engraftment or disease relapse, though occurrence of chronic GVHD and a higher CD3/CD14 ratio in G-PB and total graft may reflect a lower incidence of relapse without statistical significance.

CONCLUSIONS

The dose of CD34+ cells and the CD3/CD14 ratio in allografts seem to have prognostic value for engraftment and clinical outcomes in pediatric patients undergoing unmanipulated haploidentical hematopoietic stem cell transplantation. A lower CD3/CD14 ratio in allografts demonstrated a survival benefit.

Unmanipulated HLA-mismatched/haploidentical blood and marrow hematopoietic stem cell transplantation

Extensive ex vivo T cell-depleted or unmanipulated haploidentical transplantation provides benefits of rapid and near universal donor availability for patients without HLA-identical sibling donors or those who urgently need transplant. However, CD34 selected haplotype mismatched transplantation was limited by delayed immune reconstitution (IR), although this protocol has now been an acceptable approach. Recently, Peking University researchers developed a novel approach to HLA-mismatched/haploidentical blood and marrow transplantation without in vitro T cell depletion (GIAC protocol). This review summarizes transplant outcomes, and factors correlating with transplant outcomes following the GIAC protocol. Moreover, future challenges in improving posttransplant IR and finding the best approach reducing the incidence and severity of GVHD, whereas preserving graft-versus-leukemia effect to prevent the recurrence of underlying malignancy, are also discussed.

Comparison of unmobilized and mobilized graft characteristics and the implications of cell subsets on autologous and allogeneic transplantation outcomes

Autologous and allogeneic hematopoietic stem cell transplantation (HSCT) are considered the standard of care for many malignancies, including lymphoma, myeloma, and some leukemias. In many cases, mobilized peripheral blood has become the preferred source of hematopoietic stem cells. The efficacy of different mobilization regimens and transplantation outcomes based on cell doses has been well studied; however, the characteristics of the stem cell graft may be of equal importance with respect to patient outcomes following autologous or allogeneic HSCT. This review summarizes available preclinical and clinical data for bone marrow and mobilized peripheral blood HSCT characteristics, defined as the cell types found in the graft as well as their gene expression profiles. It also explores how graft characteristics can affect bone marrow homing, engraftment, immune reconstitution, and other posttransplantation outcomes in both the allogeneic and autologous HSCT settings.