Immunologic Autograft Engineering and Survival in Non-Hodgkin Lymphoma

Impact of plerixafor use in the mobilization of blood grafts for autologous hematopoietic cell transplantation

Plerixafor (PLER), a reversible antagonist of the CXC chemokine receptor type 4, has been in clinical use for mobilization of blood grafts for autologous hematopoietic cell transplantation (AHCT) for about 15 years. Initially PLER was investigated in placebo-controlled trials with the granulocyte colony-stimulating factor (G-CSF) filgrastim. It has also been used in combination with chemotherapy plus G-CSF in patients who had failed a previous mobilization attempt or appeared to mobilize poorly with current mobilization (preemptive use). This review summarizes what is known regarding addition of PLER to standard mobilization regimens. PLER increases mobilization of CD34+ cells, decreases the number of apheresis sessions needed to achieve collection targets and increases the proportion of patients who can proceed to AHCT. It appears also to increase the amount of various lymphocyte subsets in the grafts collected. In general, hematologic recovery after AHCT has been comparable to patients mobilized without PLER, although slower platelet recovery has been observed in some studies of patients who mobilize poorly. In phase III studies, long-term outcome has been comparable to patients mobilized without PLER. This also appears to be the case in patients receiving plerixafor for poor or suboptimal mobilization of CD34+ cells. In practice, PLER is safe and has not been shown to increase tumor cell mobilization.

Day 100 Natural Killer Cell/CD14+HLA-DRDIM ratio and survival in lymphoma post-autologous peripheral blood hematopoietic stem cell transplantation

INTRODUCTION

The infusion of autograft Natural Killer Cells (NKC)/CD14+ HLA-DRDIM ratio is a predictor of survival in lymphoma patients undergoing autologous peripheral blood hematopoietic stem cell transplantation (APBHSCT). This study evaluated if the Day 100 NKC/CD14+ HLA-DRDIM ratio still functions as a prognostic immune-biomarker.

METHODS

This was a retrospective, single-institution, cohort analysis including 107 patients in this study that had clinical assessment at Day 100 post-APBHSCT from our prior phase III trial. We evaluated the prognostic ability of the Day 100 NKC/CD14+ HLA-DRDIM ratio to predict overall survival (OS) and progression-free survival (PFS) using Cox regression model for outcome analysis and survival by Kaplan-Meier method.

RESULTS

The median follow-up from day 100 was 94.7 months (range 4.83-158.1 months) for the entire cohort. Patients with a Day 100 NKC/CD14+ HLA-DRDIM ratio ≥1.67 experienced better OS and PFS versus those with a Day 100 NKC/CD14+ HLA-DRDIM ratio <1.67: median OS was not reached versus 49.7 months, the 5-year OS rates were 91% (95% CI, 81%-96%) versus 40% (95% CI, 27%-55%), p < .0001, respectively; and median PFS was not reached versus 23.5 months, the 5-year PFS rates were 66% (95% CI, 55%-81%) versus 21% (95% CI, 15%-40%), p < .0001, respectively. Day 100 NKC/CD14+ HLA-DRDIM ratio was an independent predictor for OS and PFS in the multivariate analysis.

CONCLUSIONS

Day 100 NKC/CD14+ HLA-DRDIM ratio is a prognostic immune-biomarker in lymphoma patients post- APBHSCT.

Stem cell mobilization in multiple myeloma: challenges, strategies, and current developments

Among hematological malignancies, multiple myeloma (MM) represents the leading indication of autologous hematopoietic stem cell transplantation (auto-HCT). Auto-HCT is predominantly performed with peripheral blood stem cells (PBSCs), and the mobilization and collection of PBSCs are essential steps for auto-HCT. Despite the improved success of conventional methods with the incorporation of novel agents for PBSC mobilization in MM, mobilization failure is still a concern. The current review comprehensively summarizes various mobilization strategies for mobilizing PBSCs in MM patients and the evolution of these strategies over time. Moreover, existing evidence substantiates that the mobilization regimen used may be an important determinant of graft content. However, limited data are available on the effects of graft characteristics in patient outcomes other than hematopoietic engraftment. In this review, we discussed the effect of graft characteristics on clinical outcomes, mobilization failure, factors predictive of poor mobilization, and potential mobilization regimens for such patients.

Effect of Autograft CD34+ Dose on Outcome in Pediatric Patients Undergoing Autologous Hematopoietic Stem Cell Transplant for Central Nervous System Tumors

BACKGROUND

Consolidation with autologous hematopoietic stem cell transplantation (HSCT) has improved survival for patients with central nervous system tumors (CNSTs). The impact of the autologous graft CD34+ dose on patient outcomes is unknown.

OBJECTIVES

To analyze the relationship between CD34⁺ dose, total nucleated cell (TNC) dose, and clinical outcomes, including overall survival (OS), progression free survival (PFS), relapse, non-relapse mortality (NRM), endothelial-injury complications (EIC), and time to neutrophil engraftment in children undergoing autologous HSCT for CNSTs.

STUDY DESIGN

A retrospective analysis of the CIBMTR database was performed. Children aged <10 years who underwent autologous HSCT between 2008-2018 for an indication of CNST were included. An optimal cut point was identified for patient age, CD34⁺ cell dose, and TNC, using the maximum likelihood method and PFS as an endpoint. Univariable analysis for PFS, OS, and relapse was described using the Kaplan-Meier estimator. Cox models were fitted for PFS and OS outcomes. Cause-specific hazards models were fitted for relapse and NRM.

RESULTS

One hundred fifteen patients met the inclusion criteria. A statistically significant association was identified between autograft CD34+ content and clinical outcomes. Children receiving >3.6×10⁶/kg CD34⁺ cells experienced superior PFS (p=0.04) and OS (p=0.04) compared to children receiving ≤3.6×10⁶/kg. Relapse rates were lower in patients receiving >3.6×10⁶/kg CD34⁺ cells (p=0.05). Higher CD34⁺ doses were not associated with increased NRM (p=0.59). Stratification of CD34⁺ dose by quartile did not reveal any statistically significant differences between quartiles for 3-year PFS (p=0.66), OS (p=0.29), risk of relapse (p=0.57), or EIC (p=0.87). There were no significant differences in patient outcomes based on TNC, and those receiving a TNC >4.4×10⁸/kg did not experience superior PFS (p=0.26), superior OS (p=0.14), reduced risk of relapse (p=0.37), or reduced NRM (p=0.25). Children with medulloblastoma had superior PFS (p<0.001), OS (p=0.01), and relapse rates (p=0.001) compared to those with other CNS tumor types. Median time to neutrophil engraftment was 10 days vs 12 days in the highest and lowest infused CD34+ quartiles, respectively.

CONCLUSIONS

For children undergoing autologous HSCT for CNSTs, increasing CD34⁺ cell dose was associated with significantly improved OS and PFS, and lower relapse rates, without increased NRM or EICs.

Natural Killer Cells Are Key Host Immune Effector Cells Affecting Survival in Autologous Peripheral Blood Hematopoietic Stem Cell Transplantation

The infusion of autograft immune effector cells directly impacts the clinical outcomes of patients treated with autologous peripheral blood hematopoietic stem cell transplantation, suggesting the possibility of an autologous graft-versus tumor cells. Furthermore, the early recovery of immune effector cells also affects survival post-autologous peripheral blood hematopoietic stem cell transplantation. Natural killer cells are among the immune effector cells reported to be collected, infused, and recovered early post-autologous peripheral blood hematopoietic stem cell transplantation. In this review, I attempt to give an update on the role of natural killer cells regarding improving survival outcomes on patients treated with autologous peripheral blood hematopoietic stem cell transplantation.

The Impact of Infused Autograft Absolute Numbers of Immune Effector Cells on Survival Post-Autologous Stem Cell Transplantation

Autologous stem cell transplantation treatment has been viewed as a therapeutic modality to enable the infusion of higher doses of chemotherapy to eradicate tumor cells. Nevertheless, recent reports have shown that, in addition to stem cells, infusion of autograft immune effector cells produces an autologous graft-versus-tumor effect, similar to the graft-versus-tumor effect observed in allogeneic-stem cell transplantation, but without the clinical complications of graft-versus-host disease. In this review, I assess the impact on clinical outcomes following infusions of autograft-antigen presenting cells, autograft innate and adaptive immune effector cells, and autograft immunosuppressive cells during autologous stem cell transplantation. This article is intended to provide a platform to change the current paradigmatic view of autologous stem cell transplantation, from a high-dose chemotherapy-based treatment to an adoptive immunotherapeutic intervention.

Comparison of hematopoietic progenitor cell collection using different inlet flow rates with the Fenwal Amicus

PURPOSE

We have used a hematopoietic progenitor cell (HPC) algorithm (standard [STD]) that restricted the inlet flow rate to 65 mL/min for peripheral white blood cell count (PWBC) >35 × 109 /L (STD). In this study, we evaluated a technique that allows 85 mL/min, regardless of the PWBC count (high). For patients with PWBC >35 × 109 /L, a prospective, randomized comparison of the high flow rate vs the STD PWBC-based flow rate (65 mL/min) was performed, comparing CD34+ and lymphocyte yields, collection efficiencies (CE1), mononuclear cells (MNC), and granulocytes, red blood cell (RBC), and platelet content.

METHODS

The Fenwal Amicus version 4.5 with a heparinized ACD-A anticoagulant (AC) delivered at a 26:1 AC ratio was used. Paired comparisons between high and STD techniques were assessed with Wilcoxon signed rank tests, with P < .05 considered significant. Data are summarized as medians.

RESULTS

Forty patient pairs (autologous) were compared. Diagnoses included primarily multiple myeloma (60%) and lymphoma (37.5%). High had significantly higher median average inlet rates (69 vs 55 mL/min), whole blood processed (20 vs 16 L), and cycles (15 vs 14) than STD. There were no significant differences in pre-procedure counts. Collection contents were (high/STD): 306/328 × 106 CD34+ cells, 48/59% CD34+ CE1 (significant), 0.2/0.2 × 109 /kg lymphocytes, 45/57% lymphocyte CE1, 63/59 × 109 WBC, 15/16 × 109 granulocytes, and 1.9/1.7 × 1011 platelets.

CONCLUSIONS

The simpler, standardized high flow technique did not significantly increase or decrease CD34+ cells or lymphocyte yields, but did significantly decrease CD34+ CE1. The effects on cross-cellular content were minimal and not clinically significant.

Long-term outcome of immunologic autograft engineering

Our phase III trial reported that autograft-absolute lymphocyte count (A-ALC) improved survival post-autologous peripheral blood hematopoietic stem cell transplantation (APBHSCT) for a short-term follow-up of 2 years. We evaluated retrospectively in our phase III trial patients that the A-ALC still confers survival benefit with a longer follow-up. With a median follow-up of 127.6 months, patients infused with an A-ALC ≥ 0.5 × 10⁹ cells/kg experienced better overall survival (HR = 0.392, 95% confidence of interval [CI]: 0.224-0.687, p < 0.001) and progression-free survival (HR = 0.413, 95% CI: 0.253-0.677), p < 0.0004). This study supports that A-ALC provides long-term survival benefit post APBHSCT.

The association of mobilising regimen on immune reconstitution and survival in myeloma patients treated with bortezomib, cyclophosphamide and dexamethasone induction followed by a melphalan autograft

G-CSF only mobilisation has been shown to enhance immune reconstitution early post-transplant, but its impact on survival remains uncertain. We undertook a retrospective review of 12 transplant centres to examine overall survival (OS) and time to next treatment (TTNT) following melphalan autograft according to mobilisation method (G-CSF only vs. G-CSF and cyclophosphamide [CY]) in myeloma patients uniformly treated with bortezomib, cyclophosphamide and dexamethasone induction. Six centres had a policy to use G-CSF alone and six to use G-CSF + CY. Patients failing G-CSF only mobilisation were excluded. 601 patients were included: 328: G-CSF + CY, 273: G-CSF only. Mobilisation arms were comparable in terms of age, Revised International Staging System (R-ISS) groups and post-transplant maintenance therapy. G-CSF + CY mobilisation generated higher median CD34 + yields (8.6 vs. 5.5 × 10⁶/kg, p < 0.001). G-CSF only mobilisation was associated with a significantly higher lymphocyte count at day 15 post-infusion (p < 0.001). G-CSF only mobilisation was associated with significantly improved OS (aHR = 0.60, 95%CI 0.39-0.92, p = 0.018) and TTNT (aHR = 0.77, 95%CI 0.60-0.97, p = 0.027), when adjusting for R-ISS, disease-response pre-transplant, age and post-transplant maintenance therapy. This survival benefit may reflect selection bias in excluding patients with unsuccessful G-CSF only mobilisation or may be due to enhanced autograft immune cell content and improved early immune reconstitution.

Infused Autograft Absolute Lymphocyte Count Predicts Superior Survival in Diffuse Large B Cell Lymphoma Patients Post-Autologous Peripheral Blood Hematopoietic Stem Cell Transplantation: A Matched Case-Control Study

Our group published a double phase III trial showing that patients infused with an autograft absolute lymphocyte count (A-ALC) ≥0.5 × 10⁹ cells/kg experienced superior survival post-autologous peripheral blood hematopoietic stem cell transplantation (APBHSCT). Based on the results from our phase III study, as well as published retrospective studies, on April 1, 2017, our Bone Marrow Transplant Program changed our standard practice to collect an A-ALC ≥0.5 × 10⁹ cells/kg in addition to stem cells for lymphoma patients undergoing APBHSCT. The primary objective of the present study was to continue to assess the prognostic ability of A-ALC by evaluating overall survival (OS) and progression-free survival (PFS) of diffuse large B cell lymphoma (DLBCL) patients who underwent APBHSCT after April 1, 2017, compared with matched control groups at a 1:1:1 ratio with DLBCL patients infused with an A-ALC <0.5 × 10⁹ cells/kg and A-ALC ≥0.5 × 10⁹ cells/kg before April 1, 2017. Using the GREEDY algorithm, 85 DLBCL patients (cases) infused with an A-ALC ≥0.5 × 10⁹ cells/kg after April 1, 2017, were matched at a 1:1:1 ratio with control groups of DLBCL patients who underwent transplantation before April 1, 2017: patients infused with an A-ALC <0.5 × 10⁹ cells/kg (control 1) and patients infused with an A-ALC ≥0.5 × 10⁹ cells/kg (control 2) before April 1, 2017. Groups were matched in terms of sex, age, stage, lactate dehydrogenase (LDH) level, performance status, extranodal disease, International Prognostic Index (IPI), and disease status before APBHSCT (complete or partial response). Survival follow-up was truncated at 3 years from the date of transplantation. Cases, control 1, and control 2 were balanced as to age (P = .8), sex (P = .9), LDH (P = .6), performance status (P = .5), extranodal disease (P = .2), IPI (P = .6), and disease status before APBHSCT (P = .2). Cases and control 2 showed superior OS and PFS compared with control 1. Multivariate analysis including all patients continued to show A-ALC ≥0.5 × 10⁹ cells/kg as an independent predictor for OS (hazard ratio [HR], 0.382; 95% confidence interval [CI], 0.241 to 0.605; P < .0001) and PFS (HR, 0.437; 95% CI, 0.279 to 0.629; P < .0001). Our matched case-control study supports the results of previously published retrospective studies and our phase III study showing that the infusion of A-ALC is a prognostic factor for survival in DLBCL patients undergoing APBHSCT. Our findings support the practice of collecting not only enough stem cells for hematologic engraftment, but also enough immune effector cells (ie, A-ALC) to improve clinical outcomes in DLBCL patients post-APBHSCT.

Importance of early immune recovery after autologous hematopoietic cell transplantation in lymphoma patients

Lymphomas constitute the second most common indication for autologous hematopoietic cell transplantation (AHCT). Graft infusion is followed by a rapid hematological recovery and slower immune recovery. The number of natural killer cells and CD3⁺ T lymphocytes achieve normal counts usually within a month, whereas the recovery of CD3⁺CD4⁺ T lymphocytes is much slower. Early immune recovery is usually defined as the absolute lymphocyte count (ALC) ≥0.5 × 10⁹/L, which has been associated with improved progression-free and even overall survival. Several factors have been associated with early immune recovery, including higher infused lymphocyte and CD34⁺ cell doses, both of which are affected by the choice of mobilization. This review summarizes the clinical importance of early immune recovery for long-term success of AHCT in lymphomas. Factors known to affect early immune recovery are discussed and suggestions made how to improve mobilization and collection processes to optimize immune recovery and post-transplant outcomes.

Peripheral blood biomarkers of early immune reconstitution in newly diagnosed multiple myeloma

Peripheral blood biomarkers of tumor microenvironment and immune surveillance are independent prognostic factors in multiple myeloma. The timing and prognostic impact of immune reconstitution has been studied after autologous hematopoietic stem cell transplantation, less is known about its significance in newly diagnosed multiple myeloma. We studied absolute lymphocyte (ALC) and absolute monocyte (AMC) counts at the time of treatment initiation and 1 month thereafter in 771 newly diagnosed patients. Two hundred and thirty-four patients (31%) had evidence of immune dysregulation at baseline (abnormal biomarkers). Eighty-seven of these patients (37%) recovered normal biomarkers at 1 month (early immune reconstitution). The absence of immune dysregulation at baseline (compared to the presence thereof) was associated with better overall survival (HR 0.77, 95% CI 0.61-0.97, P = 0.025, n = 771). The absence of immune dysregulation at 1 month (compared to the persistence or development thereof) was associated with better overall survival (HR 0.63, 95% CI 0.50-0.80, P < 0.001, n = 771). Early immune reconstitution (compared to the persistence or development of immune dysregulation) was associated with better overall survival (HR 0.62, 95% CI 0.43-0.92, P = 0.016, n = 771). Cytogenetic high-risk disease was negatively, and treatment with immunomodulators positively, associated with early immune reconstitution. The presence or development of immune dysregulation in newly diagnosed multiple myeloma is an independent risk factor. The favorable impact of early immune reconstitution suggests immune dysregulation to be a potentially modifiable risk factor that may be exploited for therapeutic benefit.

Autograft immune effector cells and survival in autologous peripheral blood hematopoietic stem cell transplantation

In addition to stem cells, T-cells, natural killer cells, dendritic cells, and monocytes are also collected and infused from the autograft in patients undergoing autologous peripheral blood hematopoietic stem cell transplantation. Recent reports have shown that these autograft immune effector cells can affect the clinical outcome postautologous peripheral blood hematopoietic stem cell transplantation. In this article, I will review the clinical impact on the survival of these autograft immune effector cells conferring the concept of autologous graft versus tumor effect.

Infusion of autograft natural killer cell/CD14+HLA-DRDIM cell ratio predicts survival in lymphoma post autologous stem cell transplantation

The infusion of autograft absolute lymphocyte count (A-ALC) and autograft natural killer cells (A-NKC) are prognostic factors for overall survival (OS) and PFS in non-Hodgkin's lymphoma (NHL) patients undergoing autologous peripheral blood hematopoietic stem cell transplantation (APBHSCT). The human monocytic CD14⁺HLA-DR^DIM cells are associated with worse prognosis in NHL. Thus, we investigated whether the autograft A-NKC/A-CD14⁺HLA-DR^DIM ratio predicts survival in NHL. In a total of 111 NHL patients, we analyzed apheresis collection samples for the content of A-NKC and A-CD14⁺HLA-DR^DIM. With a median follow-up of 57.2 months (range: 2.1-84.6 months), patients with an A-NKC/A-CD14⁺HLA-DR^DIM ratio of ⩾0.29 experienced superior OS (5-year OS rates of 84% (95% confidence interval (CI), 72-91%) vs 48% (95% CI, 34-62%), P<0.0002, respectively) and PFS (5-year PFS rates of 59% (95% CI, 47-71%) vs 32% (95% CI, 20-48%), P<0.002, respectively). Multivariate analysis revealed that A-NKC/A-CD14⁺HLA-DR^DIM ratio was an independent predictor for PFS (hazard ratio (HR)=0.56, 95% CI, 0.32-0.96, P<0.03) and OS (HR=0.34, 95% CI, 0.16-0.68, P<0.002). The A-NKC/A-CD14⁺HLA-DR^DIM ratio provides a platform to target specific autograft immune effector cells to improve clinical outcomes in NHL patients undergoing APBHSCT.

A systems biology approach to investigating the influence of exercise and fitness on the composition of leukocytes in peripheral blood

BACKGROUND

Exercise immunology has become a growing field in the past 20 years, with an emphasis on understanding how different forms of exercise affect immune function. Mechanistic studies are beginning to shed light on how exercise may impair the development of cancer or be used to augment cancer treatment. The beneficial effects of exercise on the immune system may be exploited to improve patient responses to cancer immunotherapy.

METHODS

We investigated the effects of acute exercise on the composition of peripheral blood leukocytes over time in a male population of varying fitness. Subjects performed a brief maximal intensity cycling regimen and a longer less intense cycling regimen at separate visits. Leukocytes were measured by multi-parameter flow cytometry of more than 50 immunophenotypes for each collection sample.

RESULTS

We found a differential induction of leukocytosis dependent on exercise intensity and duration. Cytotoxic natural killer cells demonstrated the greatest increase (average of 5.6 fold) immediately post-maximal exercise whereas CD15⁺ granulocytes demonstrated the largest increase at 3 h post-maximal exercise (1.6 fold). The longer, less intense endurance exercise resulted in an attenuated leukocytosis. Induction of leukocytosis did not differ in our limited study of active (n = 10) and sedentary (n = 5) subjects to exercise although we found that in baseline samples, sedentary individuals had elevated percentages of CD45RO⁺ memory CD4⁺ T cells and elevated proportions of CD4⁺ T cells expressing the negative immune regulator programmed death-1 (PD-1). Finally, we identified several leukocytes whose presence correlated with obesity related fitness parameters.

CONCLUSIONS

Our data suggests that leukocytes subsets are differentially mobilized into the peripheral blood and dependent on the intensity and duration of exercise. Pre-existing compositional differences of leukocytes were associated with various fitness parameters.

Autologous Graft-versus-Tumor Effect: Reality or Fiction?

In contrast to allogeneic hematopoietic stem cell transplantation, the current dogma is not an evidence of graft-versus-tumor effect in autologous hematopoietic stem cell transplantation; thus, it is assumed that autologous hematopoietic stem cell transplantation only relies on the high-dose chemotherapy to improve clinical outcomes. However, recent studies argue in favor of the existence of an autologous graft-versus-tumor without the detrimental complications of graft-versus-host disease due to the nonspecific immune response from the infused donor alloreactive immune effector cells in allogeneic hematopoietic stem cell transplantation. Herein, this paper reviews the clinical evidence of an autologous graft-versus-tumor effect based on the autograft collected and infused host immune effector cells and host immunity recovery after autologous hematopoietic stem cell transplantation affecting clinical outcomes in cancer patients.