Armin Gerbitz

Background/Objectives: Smoking is linked to an increased risk of pulmonary complications and adverse outcomes following allogeneic hematopoietic cell transplantation (Allo-HCT). Unfortunately, data is rarely correlated with the incidence of GVHD and does not show whether smoking has a negative impact independent from underlying pulmonary comorbidities. Methods: We retrospectively analyzed 407 patients who underwent Allo-HCT between January 2019 and May 2021 and evaluated the impact of smoking history and pre-transplant pulmonary comorbidities on the risk of outcomes including graft-versus-host disease (GVHD), overall survival (OS), and non-relapse mortality (NRM). Results: Patients were divided into the following groups: Group A: smokers with pre-transplant pulmonary comorbidity, 40 pts (9.8%); Group B: non-smokers with pre-transplant pulmonary comorbidity, 71 pts (17.4%); Group C: smokers without pre-transplant pulmonary comorbidity, 105 pts (25.8%); and Group D: non-smokers without pre-transplant pulmonary comorbidity, 191 pts (46.9%). Smokers were also grouped by their smoking history (25 pack-years (35 pts)) and by smoking recency: Recent (until Allo-HCT), Former (quit > 1 year ago), and Remote smokers (quit > 10 years ago). Our results showed that Group A demonstrated increased chronic lung GVHD compared to the other groups (p = 0.01). The 3-year OS was lowest in Group A at 45.0%, compared to 70.4%, 62.4%, and 69.4% (p = 0.006), and the NRM was highest at 37.5%, compared to 15.5%, 18.2%, and 14.7% in Groups B, C, and D, respectively (p = 0.001). Smoking recency and higher pack-year dose were associated with worse outcomes. Conclusions: Our study demonstrated the negative synergistic effect of smoking history and pre-transplant pulmonary comorbidities on the incidence of lung GVHD, OS, and NRM.

Background.: Despite decades of post–allogeneic hematopoietic cell transplantation (HCT) growth factor utilization, its role remains undefined, leading to ongoing debates and research. The theoretical impacts of growth factors have been challenged in numerous studies. Methods.: In this retrospective cohort study conducted at the Princess Margaret Cancer Centre, we analyzed the clinical outcomes of 509 patients who underwent allogeneic HCT between May 1, 2019, and May 31, 2022. This study aimed to assess the impact of granulocyte colony-stimulating factor (G-CSF) administration posttransplantation on neutrophil and platelet engraftment, incidence of bloodstream infections (BSIs), graft-versus-host disease, engraftment syndrome (ES), and survival metrics including overall survival, nonrelapse mortality, and graft-versus-host disease–free/relapse-free survival. Results.: Our findings indicate that G-CSF administration expedited neutrophil engraftment (16 versus 18 d, P = 0.009) and was associated with a decreased incidence of BSI (9.4% versus 31.3%, P = 0.014). However, this benefit was counterbalanced by a significant delay in platelet engraftment (21 versus 17 d, P < 0.001). Multivariate logistic regression analysis identified mismatched donors (odds ratio, 1.72; 95% confidence interval, 1.03-2.88; P = 0.038) and the duration of G-CSF therapy (odds ratio, 1.04; 95% confidence interval, 1.00-1.09; P = 0.038) as independent predictors for the development of ES. Despite these hematological impacts, there was no observed advantage in overall survival, nonrelapse mortality, or graft-versus-host disease–free/relapse-free survival among patients who received G-CSF compared with those who did not. Conclusions.: Although G-CSF post-HCT expedited neutrophil engraftment and reduced BSI risk, it did not result in a survival advantage. The association with ES necessitates careful consideration.

Over-expression of the proto-oncogene c-MYC is frequently observed in a variety of tumors and is a hallmark of Burkitt´s lymphoma. The fact that many tumors are oncogene-addicted to c-MYC, renders c-MYC a powerful target for anti-tumor therapy. Using a xenogenic vaccination strategy by immunizing C57BL/6 mice with human c-MYC protein or non-homologous peptides, we show that the human c-MYC protein, despite its high homology between mouse and man, contains several immunogenic epitopes presented in the context of murine H2^b haplotype. We identified an MHC class II-restricted CD4⁺ T-cell epitope and therein an MHC class I-restricted CD8⁺ T-cell epitope (SSPQGSPEPL) that, after prime/boost immunization, protected up to 25% of mice against a lethal lymphoma challenge. Lymphoma-rejecting animals contained MHC multimer-binding CD8⁺ cell within the peripheral blood and displayed in vivo cytolytic activity with specificity for SSPQGSPEPL. Taken together these data suggest that oncogenic c-MYC can be targeted with specific T-cells.

To study mechanisms of T cell-mediated rejection of B cell lymphomas, we developed a murine lymphoma model wherein three potential rejection antigens, human c-MYC, chicken ovalbumin (OVA), and GFP are expressed. After transfer into wild-type mice 60–70% of systemically growing lymphomas expressing all three antigens were rejected; lymphomas expressing only human c-MYC protein were not rejected. OVA expressing lymphomas were infiltrated by T cells, showed MHC class I and II upregulation, and lost antigen expression, indicating immune escape. In contrast to wild-type recipients, 80–100% of STAT1-, IFN-γ-, or IFN-γ receptor-deficient recipients died of lymphoma, indicating that host IFN-γ signaling is critical for rejection. Lymphomas arising in IFN-γ- and IFN-γ-receptor-deficient mice had invariably lost antigen expression, suggesting that poor overall survival of these recipients was due to inefficient elimination of antigen-negative lymphoma variants. Antigen-dependent eradication of lymphoma cells in wild-type animals was dependent on cross-presentation of antigen by cells of the tumor stroma. These findings provide first evidence for an important role of the tumor stroma in T cell-mediated control of hematologic neoplasias and highlight the importance of incorporating stroma-targeting strategies into future immunotherapeutic approaches.