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

Increased PD-1 Expression on Circulating T Cells Correlates with Inferior Outcome after Autologous Stem Cell Transplantation

High-dose chemotherapy followed by autologous stem cell transplantation (auto-SCT) is a well-established treatment option for multiple myeloma and malignant lymphoma patients. It is able to induce long-term progression-free survival (PFS) in both patient groups and even provide a cure in patients with aggressive lymphoma. However, relapse is common and has been associated with the pace and quality of immunologic reconstitution after transplantation, as well as with immune cell exhaustion and immunometabolic defects. We aimed to analyze the dynamics of the prototypical exhaustion marker PD-1 on immune cells during reconstitution on high-dose chemotherapy followed by auto-SCT and its impact on PFS. We performed a comprehensive analysis of exhaustion and metabolic markers on immune cells from myeloma and lymphoma patients undergoing auto-SCT using flow cytometry and NanoString technologies. The expression levels of PD-1 were increased during early reconstitution after transplantation on T cells and natural killer (NK) cells, as well as on monocytes. However, while PD-1 expression in NK cells and monocytes normalized over time, PD-1 expression on T cells demonstrated a variable course. Of note, lymphoma patients with continuously increasing PD-1 expression on T cells after auto-SCT had an inferior median PFS of only 146 days, whereas the median PFS was not reached in the lymphoma patients without such a PD-1 expression pattern. T cells from patients with increased PD-1 expression after auto-SCT exhibited an immunometabolic (over)activation and exhausted phenotype compared to T cells from patients with a low PD-1 expression after transplantation, including higher levels of the glycolytic pacemaker enzyme hexokinase 2 and the inhibitory receptor CTLA-4. In addition, proliferating Ki-67+ T cells were more abundant in patients with high PD-1 expression on T cells compared to those with low expression after auto-SCT (11.9% versus 4.2%). PD-1 expression on T cells might serve as an adverse biomarker for lymphoma patients undergoing auto-SCT; however, further validation by larger prospective studies is required.

The metabolic profile of reconstituting T-cells, NK-cells, and monocytes following autologous stem cell transplantation and its impact on outcome

Previous studies indicated a role of the reconstituting immune system for disease outcome upon high-dose chemotherapy (HDCT) and autologous stem cell transplantation (auto-SCT) in multiple myeloma (MM) and lymphoma patients. Since immune cell metabolism and function are closely interconnected, we used flow-cytometry techniques to analyze key components and functions of the metabolic machinery in reconstituting immune cells upon HDCT/auto-SCT. We observed increased proliferative activity and an upregulation of the glycolytic and fatty acid oxidation (FAO) machinery in immune cells during engraftment. Metabolic activation was more pronounced in T-cells of advanced differentiation stages, in CD56^bright NK-cells, and CD14⁺⁺CD16⁺ intermediate monocytes. Next, we investigated a potential correlation between the immune cells’ metabolic profile and early progression or relapse in lymphoma patients within the first twelve months following auto-SCT. Here, persistently increased metabolic parameters correlated with a rather poor disease course. Taken together, reconstituting immune cells display an upregulated bioenergetic machinery following auto-SCT. Interestingly, a persistently enhanced metabolic immune cell phenotype correlated with reduced PFS. However, it remains to be elucidated, if the clinical data can be confirmed within a larger set of patients and if residual malignant cells not detected by conventional means possibly caused the metabolic activation.

Blood Graft and Outcome After Autologous Stem Cell Transplantation in Patients With Primary Central Nervous System Lymphoma

Background

Autologous stem cell transplantation (auto-SCT) is a treatment option for patients with primary central nervous system lymphoma (PCNSL).

Methods

In this prospective multicenter study, the effects of blood graft cellular content on hematologic recovery and outcome were analyzed in 17 PCNSL patients receiving auto-SCT upfront.

Results

The infused viable CD34⁺ cell count > 1.7 × 10⁶/kg correlated with more rapid platelet engraftment (10 vs. 31 days, P = 0.027) and with early neutrophil recovery (day + 15) (5.4 vs. 1.6 × 10⁹/L, P = 0.047). A higher number of total collected CD34⁺ cells > 3.3 × 10⁶/kg infused predicted worse 5-year progression-free survival (PFS) (33% vs. 100%, P = 0.028). In addition, CD3⁺CD8⁺ T cells > 78 × 10⁶/kg in the infused graft impacted negatively on the 5-year PFS (0% vs. 88%, P = 0.016).

Conclusion

The cellular composition of infused graft seems to impact on the hematologic recovery and PFS post-transplant. Further studies are needed to verify the optimal autograft cellular content in PCNSL.

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.

Use of Plerixafor for Stem Cell Mobilization in the Setting of Autologous and Allogeneic Stem Cell Transplantations: An Update

Mobilization failure is an important issue in stem cell transplantations. Stem cells are yielded from the peripheral blood via apheresis. Granulocyte colony-stimulating factor (G-CSF) is the most commonly used mobilization agent among patients and donors. G-CSF is administered subcutaneously for multiple days. However, patients with mobilization failure cannot receive autologous stem cell transplantation and, therefore, cannot be treated adequately. The incidence rate of mobilization failure among patients is about 6–23%. Plerixafor is a molecule that inhibits the binding of chemokine receptor-4 with stromal-cell-derived factor-1, thereby resulting in the release of CD34+ cells in the peripheral blood. Currently, plerixafor is used in patients with mobilization failure with G-CSF and is administered subcutaneously. Several studies conducted on different clinical settings have shown that plerixafor is effective and well tolerated by patients. However, more studies should be conducted to explore the optimal approach for plerixafor in patients with mobilization failure. The incidence of mobilization failure among donors is lower. However, plerixafor is not approved among donors with mobilization failure. Moreover, several clinical studies in donors have shown a beneficial effect of plerixafor. In addition, the adverse events of plerixafor are mild and transient, which can overcome the adverse events due to G-CSF. This review assessed the current role and effects of plerixafor in stem cell mobilization for autologous and allogeneic stem cell transplantations.

Mobilization characteristics, blood graft composition, and outcome in diffuse large B-cell lymphoma after autologous stem cell transplantation: Results from the prospective multicenter GOA study

BACKGROUND

Diffuse large B-cell lymphoma (DLBCL) is a common indication for autologous stem cell transplantation (auto-SCT).

STUDY DESIGN AND METHODS

This prospective noninterventional study aimed to evaluate the impact of mobilization characteristics and graft cellular content on hematologic recovery and outcome after auto-SCT among 68 patients with DLBCL.

RESULTS

Better mobilization capacity as manifested by blood CD34⁺ cell count >32 × 10⁶ /L and CD34⁺ cell yield of the first apheresis >2.75 × 10⁶ /kg correlated with faster neutrophil (P = .005 and P = .017) and platelet (P = .002 and P < .001) recovery. A higher number of infused CD34⁺ cells (> 2.65 × 10⁶ /kg) was associated with better 5-year overall survival (OS; 95% vs 67%, P = .012). The graft CD34⁺ CD133⁺ CD38^- cell count >0.07 × 10⁶ /kg was predictive of better 5-year OS (87% vs 63%; P = .008) and higher graft CD3⁺ cell count (>23.1 × 10⁶ /kg) correlated also with better 5-year OS (80% vs 40%, P = .008). In multivariate analysis only disease status of CR I at auto-SCT was associated with better progression-free survival (P = .014) and OS (P = .039).

CONCLUSION

The mobilization capacity of CD34⁺ cells impacted on early hematologic recovery in patients with DLBCL after auto-SCT. Higher graft CD34⁺ cell count and both CD34⁺ CD133⁺ CD38^- and CD3⁺ cells were also associated with better OS. The effect of optimal graft cellular composition on outcome in DLBCL should be evaluated in a randomized study.

A Pilot Study of Circulating Monocyte Subsets in Patients Treated with Stem Cell Transplantation for High-Risk Hematological Malignancies

Background and Objectives: Autologous and allogeneic stem cell transplantation is used in the treatment of high-risk hematological malignancies, and monocytes are probably involved in hematological reconstitution as well as posttransplant immunoregulation. The aim of our study was to investigate the levels of circulating monocyte subsets in allotransplant recipients. Materials and Methods: The levels of the classical, intermediate, and nonclassical monocyte subsets were determined by flow cytometry. Sixteen patients and 18 healthy controls were included, and the levels were analyzed during pretransplant remission (n = 13), early posttransplant during cytopenia (n = 9), and early reconstitution (n = 9). Results: Most patients in remission showed a majority of classical monocytes. The patients showed severe early posttransplant monocytopenia, but the total peripheral blood monocyte counts normalized very early on, and before neutrophil and platelet counts. During the first 7–10 days posttransplant (i.e., during cytopenia) a majority of the circulating monocytes showed a nonclassical phenotype, but later (i.e., 12–28 days posttransplant) the majority showed a classical phenotype. However, the variation range of classical monocytes was wider for patients in remission and during regeneration than for healthy controls. Conclusions: The total peripheral blood monocyte levels normalize at the very early stages and before neutrophil reconstitution after stem cell transplantation, and a dominance of classical monocytes is reached within 2–4 weeks posttransplant.

Brachial Plexitis After Stem Cell Transplant

BACKGROUND

Brachial plexitis is characterized by acute onset pain followed by weakness due to dysfunction of the nerves constituting the brachial plexus. The exact pathophysiology of this condition remains unknown but it is known to follow acute infections, such as a viral illness.

CASE DESCRIPTION

We describe a case of idiopathic brachial plexitis in a patient after a peripheral stem cell transplant. The acute denervation of nerves in the brachial plexus may be due to reconstitution of his immune system. This is a rare entity and can be a diagnostic dilemma.

CONCLUSIONS

Brachial plexitis may follow peripheral stem cell transplantation. Awareness of this phenomenon is helpful to clinicians involved in the care of these patients.