Expression profiles of adhesion molecules on naïve T cells in bone marrow grafts of healthy donors treated with granulocyte colony-stimulating factor

Comparison of Outcomes of Haploidentical Peripheral Blood Stem Cell Transplantation Supported by Third-Party Cord Blood Versus Human Leukocyte Antigen-Matched Sibling Peripheral Blood Stem Cell Transplantation in Hematologic Malignancy Patients

Recent studies have shown that haploidentical hematopoietic stem cell transplantation supported by third-party cord blood (haplo-cord-HSCT) results in rapid hematopoietic recovery, low incidences of graft-versus-host disease (GVHD), and relapse of hematologic malignancies. However, few reports on haploidentical peripheral blood stem cell transplantation supported by third-party cord blood (haplo-cord-PBSCT) have been published. To evaluate the outcomes of patients who underwent haplo-cord-PBSCT or human leukocyte antigen (HLA)-matched sibling donor peripheral blood stem cell transplantation (MSD-PBSCT), we retrospectively reviewed the clinical data of patients with hematologic malignancies who underwent haplo-cord-PBSCT (n = 93) or MSD-PBSCT (n = 72) in our hospital from March 2017 to December 2020. In the haplo-cord-PBSCT and MSD-PBSCT groups, the median time for neutrophil and platelet engraftment was 13 vs. 12 days (p = 0.07) and 16 vs. 13 days (p = 0.06), respectively. The 30-day cumulative incidences of neutrophil engraftment were 100.0% and 98.6% (p = 0.12). The 100-day cumulative incidences of platelet engraftment were 96.8% and 98.6% (p = 0.01). The 100-day cumulative incidences of grade II–IV and grade III–IV acute GVHD were 29.1% vs. 23.6% (p = 0.42) and 9.7% vs. 4.2% (p = 0.18). The cumulative incidences of total and moderate/severe chronic GVHD at 1 year were 26.5% vs. 17.4% and 8.1% vs. 4.5%, respectively, and at 3 years were 34.7% vs. 34.3% (p = 0.60) and 13.6% vs. 10.6% (p = 0.49), respectively. The cumulative incidences of relapse at 1 year were 9.3% and 7.2% and at 3 years were 17.0% and 17.0% (p = 0.98). Non-relapse mortality (NRM) at 1 year was 14.6% and 8.6% and at 3 years was 17.4% and 8.6% (p = 0.13) in two groups. The probabilities of overall survival (OS), disease-free survival (DFS), and GVHD-free/relapse-free survival (GRFS) at 1 year were 81.7% vs. 88.6%, 76.1% vs. 84.2%, and 71.7% vs. 79.7%, respectively, and at 3 years were 78.7% vs. 79.0%, 65.6% vs. 74.4%, and 55.5% vs. 63.6%, respectively, in the corresponding group, p > 0.05. In conclusion, for patients with acute myeloid leukemia/myelodysplastic syndrome (AML/MDS) and acute lymphoid leukemia (ALL), haplo-cord-PBSCT results in similar outcomes compared with MSD-PBSCT, and it may be a valid alternative transplantation method.

Multiomics Analysis Identifies SOCS1 as Restraining T Cell Activation and Preventing Graft-Versus-Host Disease

Graft-versus-host disease (GVHD) is a major life-threatening complication of allogeneic hematopoietic stem cell transplantation (allo-HSCT). Inflammatory signaling pathways promote T-cell activation and are involved in the pathogenesis of GVHD. Suppressor of cytokine signaling 1 (SOCS1) is a critical negative regulator for several inflammatory cytokines. However, its regulatory role in T-cell activation and GVHD has not been elucidated. Multiomics analysis of the transcriptome and chromatin structure of granulocyte-colony-stimulating-factor (G-CSF)-administered hyporesponsive T cells from healthy donors reveal that G-CSF upregulates SOCS1 by reorganizing the chromatin structure around the SOCS1 locus. Parallel in vitro and in vivo analyses demonstrate that SOCS1 is critical for restraining T cell activation. Loss of Socs1 in T cells exacerbates GVHD pathogenesis and diminishes the protective role of G-CSF in GVHD mouse models. Further analysis shows that SOCS1 inhibits T cell activation not only by inhibiting the colony-stimulating-factor 3 receptor (CSF3R)/Janus kinase 2 (JAK2)/signal transducer and activator of transcription 3 (STAT3) pathway, but also by restraining activation of the inflammasome signaling pathway. Moreover, high expression of SOCS1 in T cells from patients correlates with low acute GVHD occurrence after HSCT. Overall, these findings identify that SOCS1 is critical for inhibiting T cell activation and represents a potential target for the attenuation of GVHD.

Th2 polarization in target organs is involved in the alleviation of pathological damage mediated by transplanting granulocyte colony-stimulating factor-primed donor T cells

Acute graft-versus-host disease (aGVHD) is caused by allo-activated donor T cells infiltrating target organs. As a regulator of immune function, granulocyte colony-stimulating factor (G-CSF) has been demonstrated to relieve the aGVHD reaction. However, the role of G-CSF-primed donor T cells in specific target organs is still unknown. In this study, we employed a classical MHC-mismatched transplantation mouse model (C57BL/6 into BALB/c) and found that recipient mice transplanted with G-CSF-primed T cells exhibited prolonged survival compared with that of the PBS-treated group. This protective function against GVHD mediated by G-CSF-primed donor T cells was further confirmed by decreased clinical and pathological scores in this aGVHD mouse model, especially in the lung and gut. Moreover, we found that T cells polarized towards Th2 cells and regulatory T cells were increased in specific target organs. In addition, G-CSF treatment inhibited inducible co-stimulator (ICOS) expression and increased the expression of tolerance-related genes in recipient mice. Our study provides new insight into the immune regulatory effects of G-CSF on T cell-mediated aGVHD, especially for its precise regulation in GVHD target organs.

Are we underutilizing bone marrow and cord blood? Review of their role and potential in the era of cellular therapies

Since the first hematopoietic stem cell transplant, over a million transplants have been performed worldwide. In the last decade, the transplant field has witnessed a progressive decline in bone marrow and cord blood utilization and a parallel increase in peripheral blood as a source of stem cells. Herein, we review the use of bone marrow and cord blood in the hematopoietic stem cell transplant setting, and we describe the recent advances made in different medical fields using cells derived from cord blood and bone marrow.

Rapid reconstitution of NK1 cells after allogeneic transplantation is associated with a reduced incidence of graft-versus-host disease

The balance between immunostimulation and immunoregulation in T cell immunity is achieved by maintaining specific ratios of Th1, Th2, Th3 and Tr1 cells. Here, we investigate levels of type 1 (IFN-gamma; NK1), type 2 (IL-13; NK2), type 3 (TGF-beta; NK3) and regulatory (IL-10; NKr) cytokines in peripheral blood to assess the cytokine profiles of natural killer (NK) cells following human allogeneic hematopoietic stem cell transplantation (allo-HSCT). NK2 and NK3 cell expansion was observed after allo-HSCT; levels of NKr cells reached donor levels at day 15, though levels of NK1 cells were consistently lower than donor levels until day 60 after allo-HSCT. Multivariate analysis showed that a higher level of NK1 cells by day 15 was associated with a lower overall risk of acute graft-versus-host disease (GVHD) (HR 0.157, P=0.010) as well as II-IV acute GVHD (HR 0.260, P=0.059). Furthermore, higher levels of NK1 cells by day 15 were correlated with lower rates of cytomegalovirus (CMV) reactivation (HR 0.040, 0.005-0.348, P=0.003). These results indicate that rapid reconstitution of NK cells, especially NK1 cells, can help prevent the development of GVHD as well as CMV reactivation after allogeneic transplantation.

Mechanisms for T cell tolerance induced with granulocyte colony-stimulating factor

Granulocyte colony-stimulating factor (G-CSF) has been widely accepted as a mediator of T cell tolerance. The immune modulatory effect of G-CSF on T cells is believed to be mediated exclusively through other effector cells, such as monocytes, tolerogenic dendritic cells (DC), and myeloid-derived suppressor cells. Recent advances confirmed the direct effects of G-CSF in inducing immune tolerance of T cells through the G-CSF-G-CSF receptor pathway and related molecular mechanisms. This review aims to summarize the findings associated with the direct and indirect mechanisms for T cell tolerance induced with G-CSF. The role of G-CSF in preventing graft-versus-host disease (GVHD) and in treating autoimmune diseases (ADs) is also discussed. It is conceivable that G-CSF and immune cell compositions, such as tolerogenic DC and CD4(+)CD25(+)Foxp3(+) T cells, modulated by G-CSF could become an integral part of the immunomodulatory therapies against GVHD and ADs in the future.

Higher frequency of regulatory T cells in granulocyte colony-stimulating factor (G-CSF)-primed bone marrow grafts compared with G-CSF-primed peripheral blood grafts

BACKGROUND

Regulatory T cells (Treg) in allografts are important for the prevention of graft-versus-host disease (GVHD) post-transplantation. The aim of this study was to compare the contents of Tregs and effector T cells in granulocyte colony-stimulating factor (G-CSF)-primed bone marrow grafts (G-BM) and peripheral blood grafts (G-PB).

METHOD

G-BM and G-PB were obtained from 20 allogeneic donors. T-cell subgroups, including conventional T cells and different types of Treg cells, as well as the percentage of Ki67 expression on CD4(+)CD25(high)Foxp3(+) Treg cells, were analyzed using flow cytometry. The levels of interferon-γ (IFN-γ) and interleukin-17 (IL-17) secreted by T cells stimulated with PMA and ionomycin were also determined by flow cytometry.

RESULTS

The percentage of CD4(+)CD25(high)CD127(-/dim)CD62L(+) Treg cells was significantly higher in the G-BM group, with higher proportions of CD45RA(+) naïve Treg cells and higher expression of CD69 on Treg cells in G-BM (P < 0.05). The percentage of Ki67 expression in CD4(+)CD25(high)Foxp3(+) Treg cells in G-BM was significantly higher than that on G-PB. The suppressive functions of Treg cells in inhibiting T-cell activation were comparable between G-BM and G-PB. The proportions of CD4(+)CD25(-)CD69(+) Treg subsets as well as Th1 cells in G-BM were also significantly higher than those in G-PB (P < 0.001). The proportions of conventional T cells and Th17 effector cells were comparable in G-BM compared with those in G-PB. Thus, the ratio of conventional T cells and CD4(+)CD25(high)CD127(-/dim) regulatory T cells were lower in G-BM than that in G-PB (P = 0.014).

CONCLUSION

In addition to the much higher T-cell counts in G-PB grafts that may contribute to more severe GVHD, the higher frequency of Treg cells and lower ratio of conventional T cells to Treg cells in G-BM compared with G-PB grafts might reduce GVHD post-transplantation in G-BM compared with G-PB transplantation.

G-CSF-primed bone marrow as a source of stem cells for allografting: revisiting the concept

The source of hematopoietic stem cells (HSCs) for allogeneic transplantation has evolved over the last decades, from the sole use of unstimulated bone marrow (BM) to the use of G-CSF (filgrastim)-mobilized peripheral blood, G-CSF-primed BM (G-BM) and cord blood. G-CSF-mobilized PBSC has replaced BM as the most commonly used source of allogeneic stem cells. G-BM is a source of HSCs, with studies demonstrating the safety and feasibility of this strategy with the potential for reducing GvHD, while retaining the speed of engraftment. Although the G-BM had lost its use as the optimal source of stem cells, after the widespread use of haploidentical transplantation, their use has resurfaced in 2010. This source can still be used in today's world of transplantation in aplastic anemia and other benign diseases, as well as in children donors. This study intends to review the evidence for this approach and whether this approach still has merit in the ever-evolving field of allogenic HSC transplantation. The merit of G-BM is its ability to offer speed of engraftment with reduced GvHD.

Haploidentical hematopoietic stem cell transplantation in adults with Philadelphia-negative acute lymphoblastic leukemia: no difference in the high- and low-risk groups

Allogeneic hematopoietic stem cell transplantation (HSCT) is the most effective post-consolidation therapy and curative option for adult patients with Philadelphia chromosome-negative (Ph-negative) acute lymphoblastic leukemia (ALL) in first complete remission (CR1). A human leukocyte antigen (HLA)-haploidentical related donor (haplo-RD) is one of the most important alternative sources for those without HLA-identical sibling donor (ISD). The present study aimed to evaluate the outcomes of haploidentical hematopoietic stem cell transplantation (haplo-HSCT) in adult Ph-negative ALL CR1 patients (n = 183). We produced an unmanipulated haplo-HSCT protocol including granulocyte colony stimulating factor (G-CSF) for all donors, intensive immune suppression, anti-thymocyte globulin, and combination of G-CSF-primed bone marrow harvest and G-CSF-mobilized peripheral blood stem cells harvest as the source of stem cell grafts. The median age for high-risk versus low-risk groups were 29 versus 23 years. Three-year incidences of relapse mortality and nonrelapse mortality for high-risk versus low-risk groups were 7.1% versus 11.1% (p = 0.498) and 18.0% versus 16.2% (p = 0.717), respectively. Three-year probabilities of disease-free survival and overall survival for high-risk versus low-risk groups were 67.6% versus 68.2% (p = 0.896) and 74.9% versus 72.7% (p = 0.981), respectively. Multivariate analysis showed that limited cGVHD and a lower pre-HSCT comorbidity burden were associated with better outcomes. In summary, comparable outcomes were observed among high- and low-risk Ph-negative ALL CR1 patients after haplo-HSCT. Haplo-RD could be considered for adults with Ph-negative ALL in CR1 as an important alternative source of donors in cases when no ISD is available.

Induced pluripotent stem cells have similar immunogenic and more potent immunomodulatory properties compared with bone marrow-derived stromal cells in vitro

AIM

To evaluate the in vitro immunogenic and immunomodulatory properties of induced pluripotent stem cells (iPSCs) compared with bone marrow-derived mesenchymal stromal cells (MSCs).

MATERIALS & METHODS

Mouse embryonic fibroblasts (MEFs) were isolated from C3HeB/FeJ and C57BL/6J mice, and reprogrammed to generate iPSCs. Mixed leukocyte reactions were performed using MHC-matched and -mismatched responder leukocytes and stimulator leukocytes, iPSCs or MSCs. To assess immunogenic potential, iPSCs and MSCs were used as stimulator cells for responder leukocytes. To assess immunomodulatory properties, iPSCs and MSCs were cultured in the presence of stimulator and responder leukocytes. MEFs were used as a control.

RESULTS

iPSCs had similar immunogenic properties but more potent immunomodulatory effects than MSCs. Co-culture of MHC-mismatched leukocytes with MHC-matched iPSCs resulted in significantly less responder T-cell proliferation than observed for MHC-mismatched leukocytes alone and at more responder leukocyte concentrations than with MSCs. In addition, MHC-mismatched iPSCs significantly reduced responder T-cell proliferation when co-cultured with MHC-mismatched leukocytes, while MHC-mismatched MSCs did not.

CONCLUSION

These results provide important information when considering the use of iPSCs in place of MSCs in both regenerative and transplantation medicine.

Advancement of human leukocyte antigen-partially matched related hematopoietic stem cell transplantation

Allogeneic hematopoietic stem cell transplantation (HSCT) is one of the most effective options for hematological malignancies, and human leukocyte antigen-partially matched related donors (PMRDs) are a valuable option for HSCT. Several protocols (with or without ex vivo T-cell depletion (TCD)) have been established worldwide. TCD including CD34(+) positive selection and CD3/CD19 depletion has successfully overcome the human leukocyte antigen disparity. However, TCD is associated with prolonged immune deficiencies, increased risks of infectious complications, and high transplantation-related mortality. PMRD HSCTwithout ex vivo TCD is well developed, and numerous patients have benefitted from it. Here, we review the literature on PMRD HSCT.

Granulocyte-mobilized bone marrow

PURPOSE OF REVIEW

In the last few years, mobilized peripheral blood has overcome bone marrow as a graft source, but, despite the evidence of a more rapid engraftment, the incidence of chronic graft-versus-host disease is significantly higher with, consequently, more transplant-related mortality on the long follow-up. Overall, the posttransplant outcome of mobilized peripheral blood recipients is similar to that of patients who are bone marrow grafted. More recently, the use of bone marrow after granulocyte colony-stimulating factor (G-CSF) donor priming has been introduced in the transplant practice. Herein, we review biological acquisitions and clinical results on the use of G-CSF-primed bone marrow as a source of hematopoietic stem cells (HSC) for allogeneic stem cell transplantation.

RECENT FINDINGS

G-CSF the increases the HSC compartment and exerts an intense immunoregulatory effect on marrow T-cells resulting in the shift from Th1 to Th2 phenotype with higher production of anti-inflammatory cytokines. The potential advantages of these biological effects have been translated in the clinical practice by using G-CSF primed unmanipulated bone marrow in the setting of transplant from human leukocyte antigen (HLA)-haploidentical donor with highly encouraging results.

SUMMARY

For patients lacking an HLA-identical sibling, the transplant of G-CSF primed unmanipulated bone marrow from a haploidentical donor combined with an intense in-vivo immunosuppression is a valid alternative achieving results that are well comparable with those reported for umbilical cord blood, HLA-matched unrelated peripheral blood/bone marrow or T-cell-depleted haploidentical transplant.

A direct comparison of expression profiles of adhesion molecules on naïve T cells between cord blood and steady-state bone marrow grafts of healthy donors

INTRODUCTION

We compared the profiles of adhesion molecule expression on naïve T cells between umbilical cord blood (UCB) and steady-state bone marrow (SS-BM) grafts.

METHODS

The expressions of 4 adhesion molecules, including very late antigen 4 (VLA-4), intercellular adhesion molecule-1 (ICAM-1), L-selectin, and lymophocyte function-associated antigen-1 (LFA-1) on naïve T cells in UCB (n = 25) and SS-BM (n = 10) were analyzed using flow cytometry.

RESULTS

The expressions of ICAM-1 and L-selectin on CD4(+) T cells and CD8(+) T cells in UCB were significantly lower than those on SS-BM (P < .05 for all). The expressions of VLA-4 and LFA-1 on CD8(+) T cells in UCB were significantly lower than those of SS-BM (P = .002 and .047, respectively). Compared with SS-BM, we observed lower expression of ICAM-1 on naïve CD4(+) and CD8(+) T cells in UCB (P < .001 for all). The percentages of interferon (IFN)-γ positive cells among naïve CD4(+) and CD8(+) T-cell subsets were significantly lower in UCB, leading to ready polarization of naïve UCB T cells from a Th1 to Th2 phenotype versus those on SS-BM.

CONCLUSIONS

Our results among UCB suggested lower intensities of ICAM-1 expression on naïve T cells and their easier polarization from Th1 to Th2 elements.

Haploidentical, unmanipulated, G-CSF-primed bone marrow transplantation for patients with high-risk hematologic malignancies

Eighty patients with high-risk hematologic malignancies underwent unmanipulated, G-CSF–primed BM transplantation from an haploidentical family donor. Patients were transplanted in first or second complete remission (CR, standard-risk: n =45) or in > second CR or active disease (high-risk: n =35). The same regimen for GVHD prophylaxis was used in all cases. The cumulative incidence (CI) of neutrophil engraftment was 93% 0.1%. The 100-day CIs for II-IV and III-IV grade of acute GVHD were 24% 0.2% and 5% 0.6%, respectively. The 2-year CI of extensive chronic GVHD was 6% 0.1%. The 1-year CI of treatment-related mortality was 36% 0.3%. After a median follow-up of 18 months, 36 of 80 (45%) patients are alive in CR. The 3-year probability of overall and disease-free survival for standard-risk and high-risk patients was 54% 8% and 33% 9% and 44% 8% and 30% 9%, respectively. In multivariate analysis, disease-free survival was significantly better for patients who had standard-risk disease and received transplantations after 2007. We conclude that unmanipulated, G-CSF–primed BM transplantation from haploidentical family donor provides very encouraging results in terms of engraftment rate, incidence of GVHD and survival and represents a feasible, valid alternative for patients with high-risk malignant hematologic diseases, lacking an HLA identical sibling and in need to be urgently transplanted.

KEY POINTS

Haploidentical, unmanipulated, G-CSF-primed bone marrow transplantation. Haploidentical hematopoietic stem cell transplantation for hematologic malignancies.

IL-17-producing T cells contribute to acute graft-versus-host disease in patients undergoing unmanipulated blood and marrow transplantation

The aim of this study was to investigate the effects of IL-17-producing T cells, including Th17 and Tc17 cells, on acute graft-versus-host disease (aGVHD) in patients who had undergone granulocyte colony-stimulating factor (G-CSF)-mobilised peripheral blood progenitor cell (PBPC) and G-CSF-primed bone marrow (G-BM) transplantation. Allografts from forty-one patients were analysed for IL-17-producing T cells with respect to aGVHD. Furthermore, ten patients with aGVHD onset were monitored for the presence of Th17 cells in the peripheral blood by flow cytometry. Patients who received a higher dose of Th17 cells in the G-BM (>8.5 × 10(4) /kg, p=0.005) or a higher dose of Tc17 cells in PBPC (>16.8 × 10(4) /kg, p=0.001) exhibited a higher incidence of aGVHD. An increased Th17 population (up to 4.99% CD4(+) T lymphocytes) was observed in patients with aGVHD onset. In contrast, the percentage of Th17 population decreased drastically in aGVHD patients following treatment to achieve partial and complete remission (p=0.013 and p=0.008, respectively). All percentages of Th17 and Tc17 cells were significantly reduced after in vivo G-CSF application. Our results suggested that IL-17-producing T cells contributed to aGVHD. The application of G-CSF in vivo aided in reducing the occurrence of aGVHD through a decrease in IL-17 secretion by T cells.

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.